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[ THE REVIEW

OF

APPLIED MYCOLOGY

Vol. I

ISSUED BY THE IMPERIAL
BUREAU OF MYCOLOGY

(1) 84
L102

THE IMPERIAL BUREAU OF MYCOLOGY
KEW, SURREY

1925

All Rights Reserved

IMPERIAL BUREAU OF MYCOLOGY.

599 Honorary Committee of Management.

The Right Hon. EARL BUXTON, Chairman.

Dr. W. Bateson, F.R.S., Director, John Innes Horticultural Institution,
Merton, Surrey.

Professor V. H. Buackman, F.R.S., Professor of Plant Physiology and
Pathology, Imperial College of Science and Technology, London.

Professor F. O. Bower, F.R.S., Regius Professor of Botany, Glasgow.

Mr. A. D. Corron, Keeper of Herbarium and Library, Royal Botanic
Gardens, Kew.

Professor H. H. Dixon, F.R.S., Professor of Botany, University of Dublin.

Professor J. B. FARMER, F.R.S., Professor of Botany, Imperial College of
Science and Technology, London.

Dr. A. W. Hitt, F.R.S., Director, Royal Botanic Gardens, Kew.

Professor W. H. Lana, F.R.S., Professor of Cryptogamic Botany, Manchester.

Sir DanteL Morris, K.C.M.G.. late Imperial Commissioner of Agriculture,
West Indies.

Mr. J. Murray, Foreign Office.

Dr. G. H. Peruysrip@e£, Mycologist to the Ministry of Agriculture and
Fisheries, Harpenden, Herts.

Lt.-Col. Sir Davip Pratn, C.M.G., C.LE., F.R.S., late Director, Royal
Botanic Gardens, Kew.

Sir H. J. Reap, K.C.M.G., C.B., Colonial Office.

Dr. A. B. RenDLE, F.R.S., Keeper of Botany, British Museum (Natural
History).

Mr. H.N. Ripiey, C.M.G., F.R.S., late Director, Botanic Gardens, Singapore.

Mr. R. A. RoBertson, University Lecturer on Botany, St. Andrews.

Sir A. E. Surrey, G.B.E., F.R.S., Master of Christ’s College, Cambridge.

Professor W. SOMERVILLE, Sibthorpian Professor of Rural Economy, Oxford.

Dr. H. W. T. Wacer, F.R.S., Leeda.

General Secretary: Mr. P. A. CLUTTERBUCK, M.C. (Colonial Office),
Director and Editor: Dr. E. J. Butter, C.1.E.

ERRATA

Page 12 line 9 for ‘ europea’

54 31 ,, ‘gramineum’
54 45 ,, ‘ Cyclogonium’
61 49 ,, ‘muranium’
75 16 ,, ‘ Ersiphe’
95 lines 1

and 4 ,, ‘sempervivens’
96 line 42 ,, * Cytosporina’
109 30 ,, ‘kopkii’
122 48 ,, ‘ chromatosporum *
156 15 ,, ‘ Hemeleia’
159 13 ., ‘gramineum’
208 39 .. ‘cutharticus’
212 29 ,, ‘gramineuwm’
220 22 ,, ‘fructigena’
243 34 ,, ‘Leontodontis*
322 41 ,, ‘ Tillettia’
334 24 ,, ‘Tisdale (W. T.)’

356

357

361 2

416 14

471 20

497 45

532 +

571 12

578 40
586 29

39

27 delete ‘or
44 for ‘ atropurpurem’

“rot”

, ‘Cercosporella’

‘ Reichanst’
‘gramineum’

‘ fimbriata’

‘ Obliteration ’
‘288’

‘ Hyalospora’

read ‘europaea’

”

‘graminum ’

~ § Cycloconium ’

‘“murinum
* Erysiphe’

‘ sempervirens *

‘ Cytospora’
‘kopkei’

‘ chomatosporum ’
‘ Hemileia’
‘graminum
‘cathartica’
‘graminum ”
‘cinerea’

* Leontodon’

‘ Tilletia’
‘Tisdale (W. H.)’

‘ atropurpureum ”
‘rust’

‘ Cercospora’

‘ Reichsanst’
‘graminum’

‘ fimbriatum ’

‘ Lignification ’

‘ 88 b

*‘ Hyalopsora’

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

APPLIED MYCOLOGY

Vou. IT JANUARY 1923

SPIERENBURG (DINA). Een onbekende ziekte in de Iepen. II, [An
unknown disease of Elms. II.]—Vers/. en Meded. Plantenziek-
tenkundigen Dienst te Wageninen, 24, 31 pp., 1 fig., 4 pl., 1922.

The unknown disease of elms, which caused so much damage in
Holland in 1920 [see this Revew,i, 8, p. 277], continued its ravages
in 1921. The districts mainly affected were Brabant, the Betuwe
and various localities in the south, Rotterdam and its environs
(where the disease was extremely prevalent and severe), Alkmaar,
and Amsterdam. Sporadic cases were reported from the north-
eastern provinces, where the infection appears to be in an incipient
stage. Attacks are also reported from, France [see this Review, 1,
10, p. 334] and Belgium. According to official German statements,
elms in Germany are not affected, but Dutch visitors to the Rhine
districts believe that the disease is also present in that area. It has
not, however, actually been seen in any foreign country by the
officials attached to the Dutch Phytopathological Service.

The following are the principal varieties attacked : Ulmus cam-
pestris latifolia, U. monumentalis, U. hollandica, U. rwpelli, U.
campestris suberosa, U. americana, and U. campestris awrea. U.
vegeta appears to be immune, but this variety is not adapted to
street planting.

Affected trees may be divided into three groups according to the
symptoms manifested: (a) Comparatively young trees in which the
withering of the top leaves quickly spreads downwards, forming
a sharp contrast to the green leaves of the lowest branches. This
form of the disease appears to be fatal. (b) Large, old trees in
which one of the branches suddenly withers, to be followed within
a few weeks by others and then by the top. (c) Chiefly old trees
which appear to be more or less permanently affected. The leaves
emerge slowly in the spring and remain small. They turn colour
prematurely, dry up about the middle of July, and fall early.
Throughout the summer the foliage is scanty.

Trees, especially old ones, may show wilting of the shoots early
in the year, and later burst into new foliage which, however,

A

2

rapidly withers. Such trees rarely recover. So-called water-shoots
may often be seen on the trunk.

Severely affected trees as a rule develop buds for the following
year on their shoots, but the buds are small, and appear dried up.
In milder cases, flower buds are formed as though to continue the
species by seed.

Very old trees appear to be more resistant than the younger ones,
but this seeming immunity may be due to their larger food reserves
and available water-conducting tissue. In 1921 the disease was
much more prevalent in nurseries than in the previous year.
Usually the youngest trees attacked are not less than four years
old, but cases have again been observed in trees one year old.

In addition to the discoloration of the wood already noted [see
earlier abstract], a discoloration of the bast in the shoots of young
trees has been observed, but not frequently enough to associate
this symptom with the disease. Sometimes a brown ring appears
between the bast and the wood of the branches which, in such
cases, die rapidly. A very thin layer of healthy wood is usually
present beyond the last discoloured tissue. The latter does not
always extend the whole length of the branch, but it is always
present in the top branches of young diseased trees and in the thin
branches and roots of old ones.

Microscopical examination showed that the discoloured tissues
are plainly recognizable and always occur in the previous year’s
wood. The medullary rays usually contain large starch grains
which, in the affected parts, become brown. Spots are seen in the
walls of all the ligneous elements. Tyloses are common in the
vessels. The discoloration of the wood is irregular, very dark
stripes occurring next to lighter areas.

In the winter of 1921-22 many further cases of attack by
Eccoptogaster scolytus were noticed. The larvae of flies of undeter-
mined species were also found under the bast. Typhlocyba and
Oribata were of frequent occurrence, whilst Anthocoptes sp. were
found on 1921 shoots.

The following fungi have been isolated from diseased tissues :—
a form with Cephalosporiwm and Graphium stages, Fusarium sp.,
Monilia sp., Botrytis sp. (in 1920 but not 1921), Dematium sp.,
Ramularia sp., Phoma sp., and also bacteria.

From non-discoloured wood were isolated: Fusariwm sp., Cyto-
sporina sp., and Dematiwm pullulans (2). In spite of the rapid
development of the Cephalosporium form in culture, the mycelium
of this fungus is never visible in the tissues of the discoloured
wood.

Inoculations with Cephalosporium (with or without the Graphiwm
stage) on two and three year old elms produced the discoloration in
the wood, and cultures of such wood always yielded the same fungus
again. Other fungi also produced discoloration of the wood, but
could not be re-isolated. It has not been found possible to decide
which organism is responsible for the disease or whether the disease
is an infectious one. The writer states that some extreme influence
of a more or less general character appears to be predisposing the
elms to the attacks of fungi and bacteria which are the immediate
cause of the disease.

3

No control measures can be definitely recommended. Drastic
pruning appears to render the trees susceptible to the disease.

Hepecock (G. G.), Hann (G. G.), & Hunt (N. R.). Two important
Pine cone rusts and their new Cronartial stages.— Phytopath.,
xii, 3, pp. 199-122, 2 pl., 1922.

The paper is divided into two parts. The first by Hedgecock and
Hahn, is entitled ‘Cronartium strobilinwm (Arthur) Hedge. and
Hahn, comb. nov.’ This rust has been known in Florida and Missis-
sippi as Caeoma strobilina Arth. on Pinus palustris and P. hetero-

phylla, and frequently exerts a very damaging effect on the

reproduction of these pines. Immature, first year cones are infected
and swell up, produce pyenidia and aecidia, then usually fall. Artifi-
cial inoculations were successful in producing uredosori, sometimes
also with teleutosori, on three species of Castanea and twenty-five
species of Quercus. The fungus is fully described.

The second part by Hedgecock and Hunt is entitled ‘ Cronartium
conigenum (Pat.) Hedge. and Hunt, comb. nov.’ — Patouillard
described Caeoma conigenwm from Mexico on cones of an undeter-
mined pine. An examination of portions of the type shows that
the fungus is morphologically a Peridermiwm, and the host was
probably Pinus chihwahuana, The fungus has been found in
Arizona on this host, and causes damage to the cones. Inoculation
tests were successful on three species of Castanea and seventeen
species of Quercus.

SPAULDING (P.). Investigations of the White-Pine blister rust.—
US. Dept. of Agric. Bull. 957, 90 pp., 6 pl. (1 col.), 13 figs.,
1922.

In this comprehensive monograph the author endeavours to
present all the information at present available on the white pine
blister rust. The work is divided into the following sections: The
origin and distribution of Cronartvwm rihicola, in which the theory
of the Asiatic origin of the disease is discussed and supported; an
account of its hosts, giving a complete list of all the species of
Pinus and Ribes naturally attacked or capable of artificial infection,
with details of their relative susceptibility as far as known; the
life-history of the parasite, comprising the Peridermium stage on
pines and the Cronartium stage on Ribes, with a very full account
of the different types of infection, methods of dissemination, germina-
tion and viability of the spores, &c.; the overwintering of the fungus
on pines and on Ribes; important dates in its life-history ; and the
control of the disease. :

The author points out that there are certain significant features
in the life-history of C. ribicola and in its relation to the environ-
ment which have an influence on its control. The pyenospores
(spermatia) are apparently functionless; the aecidiospores and
uredospores are not known to infect pines but do infect Rives;
while the sporidia produced by the teleutospores are not known to
infect Ribes but do infect pine. The wind is the chief agent of
distribution, the aecidiospores being capable of infecting Rives
leaves several miles away from their source. The viability of the
uredospores appears to be soon lost, so that infection by them is

4

more limited in distance. The sporidia are still more frail and, as
a rule, can only carry infection to a distance of 100 to 600 yards.
The aecidiospores produced by the overwintered mycelium in the
pine bark are the principal source of infection of Ribes leaves in the
spring, the resulting uredospores still further disseminating the
disease. High atmospheric humidity is an essential for the germina-
tion of any of the spore forms.

The present status of the control of the white pine blister rust in
North America may be summed up as follows:—Eradication of
C. ribicola is impossible except in small, isolated, advance infections.
As a national problem control is the only feasible measure. Pro-
tection of uninfected or sparsely infected areas by the enforcement
of the present Federal quarantines is necessary, since this disease
is distributed to great distances only by means of infected nursery
stock. The western forests of white pines can be protected from
the blister rust for an indefinite period by the rigid enforcement of
the Mississippi Valley quarantine. A single diseased shipment may
undo all attempts to restrict it to the eastern forests.

A very full bibliography of 180 titles is appended.

White-Pine blister rust in the Western United States.
Agric. Cire. 226, 7 pp., 9 figs., (5 col.), 1922.
White pine blister rust (Cronartiwm ribicola), which has for some
years past been ineradicably established in New England, New
York, and the Lake States, was discovered in the autumn of 1921 to
have invaded western British Columbia [see this Review, i, p. 455]
and the Puget Sound region of Washington State. The valuable
forests of western white pine (P. monticola) and sugar pine
(P. lambertiana) are now directly threatened by this destructive
disease, and can only be saved by the rigid enforcement of the
Federal quarantines which restrict the movements of five-needle
pines, currants, and gooseberries. The co-operation of all is invoked
to assist in finding and destroying any outbreaks of the disease in
Ribes or pines. The planting of black currants is deprecated.
Approximately three-quarters of the commercial five-needle pine
stand of the United States is stated to be in the western forests.

U.S. Dept.

SPAULDING (P.). Viability of telia of Cronartium ribicola in early
winter.— Phytopath., xii, 5, pp. 221-224, 1922.

Experiments have been carried out at Bethel, Vermont, to deter-
mine how late in the season the teleutospores of Cronartiwm ribi-
cola may remain viable under natural conditions.

Vigorous leaves of five species of Ribes—nigrum, odoratum, ameri-
canum, rotundifolium, and cynosbati, bearing abundant teleutosori,
were enclosed in mosquito bags and hung out of doors on 26th Sep-
tember, 1921. Germination tests were made at intervals until 8th
December, when the experiment ended. The results obtained showed
that while teleutospores on R. cynosbati, rotundifolvwm, and odora-
twm had almost reached their limit of viability by 8th December,
those of R. americanwm retained considerable vigour and those of R.
nigrum were almost as vigorous as when first collected. It has long
been recognized that R. nigrum is far the most dangerous species
of Ribes known in relation to the blister rust of white pine.

f= Srl

~

o

Further tests showed that leaves killed suddenly by frosts bore
teleutospores of maximum germinating power, and attention is
called to the fact that the danger of infection is increased by the
ability of teleutospores to germinate in winter, when the temperature
rises a few degrees above freezing, although it is not known
whether the pines are susceptible at this season.

RaTHBUN (ANNIE E.). Root rot of Pine seedlings.—Phitopath.,
xii, 5, pp. 213-220, 1 fig., 1922.

For several years coniferous seedlings, too old to succumb to
ordinary damping-off, have been known to suffer from late damping
off and root rot. Inoculation experiments were carried out on
Pinus resinosa and P. banksiana to confirm the conclusion arrived
at by field observations, namely that damping-off fungi may be
responsible for these root injuries. The fungi tested were: Pythiwm
de Baryanum, Corticuum vagum, Fusarvwm spp., Botrytis spp.,
Phomopsis juniperovora, and Rheosporangium aphanidermatus.
The inoculum on rice mush was applied directly to the roots, which
in most cases were again covered with sterilized sand. Root rot
developed to a slight extent in the controls. The inoculations were
too few to permit more than a comparison of the virulence of
different genera. .

P. de Baryanum and the cinerea type of Botrytis caused decay
to most of the roots. A small sclerotial form of Botrytis, however,
produced no injury. C. vagwm caused a decided increase in the
amount of root rot compared with the controls. The results with
Fusarium spp. were variable but on the whole root rot was some-
what increased. RR. aphanidermatus caused no appreciable decay,
but P. juniperovora produced considerable decay in one trial with
twenty seedlings. The latter result suggests the possibility that
under favourable conditions other fungi as well as damping-off
parasites may cause root rot.

The results of these very artificial tests, though in no sense
representative, may be taken as an indication that the root decay
of pine seedlings is at least partly due to damping-off fungi.

Meier (F. C.), DRECHSLER (C.), & Eppy (E. D.). Black rot of
Carrots caused by Alternaria radicina n, sp.— Phytopath., xii,
4, pp. 157-166, 2 figs., 1 pl., 1922.

During 1918-19 complaints were made from Long Island of the
heavy losses by decay of carrots in transit and storage. Later
investigations have shown that other localities in the States of
New York, Massachusetts, and possibly Pennsylvania are also
affected.

The trouble is characterized by a progressive softening and
blackening of the tissues of the root, infection frequently starting
at the crown and extending down the core, but sometimes also
originating at other points.

A fungus was easily isolated from diseased carrots and proved to
be pathogenic both on the root and on the foliage. Search for
affected foliage in the field was not successful. The fungus, a new
species of Alternaria, is named A. radicina and is fully described.

6

A close comparison is made with a disease of the foliage of carrots
caused by Macrosporiwm carotae Ell. and Lang. The latter, how-
ever, is an obligate parasite which attacks vigorous plants, while
A. radicina is a facultative parasite affecting mature tissues, espe-
cially those of more or less bruised or wounded roots during
harvesting or storage.

VoaLino (R.). Servizio di segnalazione degli attacchi di Plasmo-
para viticola nel 1921 nelle Province di Torino, Cuneo,
Novara. [The system of forecasting attacks of Plasmopara
yiticola in 1921 in the Provinces of Turin, Cuneo, and Novara. |
—Nuovi Ann. Min. Agric., i, 1, pp. 72-80, 1922.

Meteorological conditions likely to influence epidemics of fungous
diseases of the vine were recorded at various localities and at alti-
tudes ranging from 230 to 550m. in the provinces of Turin, Cuneo,

and Novara, and the observations forwarded to the central Phyto-

pathological Station at Turin. From the data furnished by the
local observatories, fortnightly bulletins were compiled containing
particulars of the maximum and minimum temperatures, atmos-
pheric pressure, atmospheric and soil humidity, rainfall, winds,
fogs and dews, cloud, &c. All the members of the observatory
staffs were instructed to pay special attention to the rainfall, dense
fogs, and continuous dews, and to inform the central authorities
immediately of the appearance of a white efflorescence on the
vines.

The central Phytopathological Station issued preliminary instruc-
tions for preventive treatment as soon as the information received
indicated that the conditions were favourable for the germination
of the winter spores and the first infection of the vines. There-
after instructions were issued to vine-growers from time to time, in
accordance with the reports of rainfall and other meteorological
conditions supplied by the local observatories, regarding the appro-
priate treatment for every phase of the attack. These announce-
ments were published in the provincial newspapers, at the
Agricultural Colleges of the different centres, and by various
agrarian committees, co-operative associations, and syndicates.

The relatively dry and mild winter of 1920-21 was followed by
snowstorms in April which appreciably lowered the temperature

and caused considerable physiological disturbances in growing .«

plants, predisposing them to the attacks of parasites. The formation
of zoospores from the winter spores began on 12th to 15th April,
but not until 28th or 29th April did conditions admit of infection
of the tissues of the vine. ‘The first symptoms of attack became
apparent on 16th to 17th May in the entire region under discussion,
conidia being formed from 28rd to 25th May. During the last
fortnight of May and almost the whole of June, conditions were
favourable for the development of the disease, heavy dew and rain
being followed by abnormally hot days. The virulence of the
attack was most pronounced during the second half of June and
the first ten days of July, especially on neglected vines. The
persistent morning dews and the high humidity caused by evapora-
tion at soil-level facilitated the continuous propagation of the
parasite. The high temperature prevailing during the second part

4

of July and the whole of August prevented any further spread of
the attack.

PetcuH (T.). Report on the work of the Division of Botany and
Mycology.— Ann. Rept. Ceylon Dept. Agric., 1921, pp. 21-23,
1922.

Some of the diseases recorded in this Report have already been
mentioned in the Quarterly Reports of the Botanist and Mycologist
[see this Review, i, 5, p. 160; 10, p. 331]. The following are
additional details :

Russer. The irregular rainfall during the south-west monsoon
was unfavourable to leaf-fall and pod disease | Phytophthora]. and
there was no general outbreak. Root diseases were common, 43 per
cent. of the specimens examined being due to Fomes lignosus, 41
per cent. to F. lamaoensis, 11 per cent. to Ustulina zonata, and 3 per
cent. to Poriu hypobrunnea.

Tea. Branch canker on young stems caused by Macrophoma
theicola has been fairly prevalent. Like red rust [see this Review,
i, 3, p. 92] it may be attributed to the cessation of manuring which
was a consequence of the war.

Coco-nuts. The Assistant Mycologist, Mr. C. H. Gadd, carried
out experiments to determine the efficacy of Bordeaux mixture as
a preventive of the parasitic form of nut-fall, but owing to the
non-appearance of the causal organism (Phytophthora sp.) no
apparent benefit was derived from the spraying. Of the total
number of nuts removed from the palms during the year, 53-3 per
cent. fell before reaching the age of two months, probably from
natural causes; 44 per cent. were picked; and the remaining 2-7
per cent. fell before attaining maturity. A few cases of bud rot,
one of great virulence, occurred during the year.

CorFEE. JDie-back attributed to Colletotrichum incarnatum
occurred on CU. robusta. The teleutospores of Hemileia vastatrix
were found throughout the year.

The diseases caused by species of Phytophthora in Ceylon are
being investigated by Mr. Gadd, who found that a species isolated
from papaw fruits [Carica papaya] was apparently identical with
that attacking cacao and rubber ‘pods’, namely P. faberi. Cross
inoculations showed that the strains from cacao and rubber would
infect papaw fruits, though not so virulently as the papaw strain
itself. The species of Phytophthora isolated from Nam Nam fruits
(Cynometra cauliflora), which was at first believed to be identical
with P. meadii, is now regarded as a distinct species. The fungus
differs from P. meadii in its ready production of oospores in
culture, and inoculation experiments on rubber pods gave negative
results with it. ;

The species of Pestalozzia on tea, coco-nut, &c., are being investi-
gated by Mr. Bertus, the results so far obtained indicating that the
Species on tea is not the same as that on coco-nut. Mycosphaerella
citrullina was recorded on Luffa acutangula, Cephalewros minimus
on cacao twigs suffering from die-back; a species of Cladosporium
caused a disease of Setaria italica, and a bacterial disease of cannas
was observed.

8

Van Hatt (C. J. J.). Ziekten en plagen der cultuurgewassen in
Nederlandsch-Indie in 1921. [Diseases and pests of culti-
vated plants in the Dutch East Indies during 1921.]—WMeded.
Inst. voor Plantenziekten, 53, 46 pp., 1921.

The meteorological conditions during 1921 were approximately
normal, except for the excessive rainfall during the west monsoon
in February and March, and during the east monsoon in October
and December. The damage caused by fungi to the more important
crops may be summarized under the following headings:

Rice. An extremely severe outbreak of root rot of rice was
probably the aftermath of the abnormally rainy east monsoon of
1920. In Java and Madoera the loss of ‘sawah’ paddy in 1921
amounted to 12 per cent. of the entire area under rice. This
estimate does not include partially damaged crops, so that the total
figure would be at least half as much again. Helmanthosporiwm
oryzae occurred sporadically on the west coast of Sumatra.

RuBsBeR. No new diseases were reported during the year. On
the east coast of Sumatra brown bast, stripe canker (Phytophthora),
and root diseases (Porta and Fomes) were the commonest diseases
and were everywhere under treatment by recognized methods.
Hypochnus was also very widespread. The general experience
seems to point to a considerable decrease of brown bast throughout
the E. Indies as the result of the alternate day tapping system.
Pink disease (Corticiwm salmonicolor) and canker occurred sporadi-
cally in certain localities, and were principally due to the neglect
of proper precautions. In Central Java there was one severe out-
break of mouldy rot [Sphaeronema sp.|, while another estate
suffered considerable losses from a die-back of the tops of young
trees. Mildew [Oidiwim sp.]| was fairly prevalent in many districts,
and on the east coast of Sumatra some of the defoliated trees failed
to form new leaves in the rainy season. The Director of the
Besoeki Experiment Station reported a severe case of infection by
Fomes pseudoferreus (Poria hypolateritia). A few instances of
‘kringrot ’, a peeling off of the outermost bast layer, occurred on
the east coast of Sumatra.

PoTaTOES were severely attacked by leaf roll in the Tengger
district of Pasoeroean, where the disease seems to be on the increase.
Sprain also occurred in the Tengger district, and in the Residency
of Tapanoeli. Scab was recorded from the Poedjonsche district of
Pasoeroean. Slime disease (Bact. solanacearwm) was of frequent
occurrence on the ‘kentang betawi’ variety on the west coast of
Sumatra, while the more or less sweet ‘sawah’ potato was immune.
Dry rot was reported from the province of Preanger.

SUGAR-CANE in Java was severely attacked during the early part
of the year by pineapple disease (Thielaviopsis ethuceticus). Red
rot [Colletotrichwm falcatum] occurred on one estate, and root rot
was reported from all parts, especially in the variety EK 28. The
yellow stripe [mosaic] and sereh diseases were not of much impor-
tance. Gummosis occurred sporadically all over Java, but in most
cases the attacks were very mild.

Topacco. At the Deli Experiment Station extremely virulent
outbreaks occurred of Phytophthora nicotianae and slime disease
(Bact. solanacearum), especially the latter which was prevalent

3

both in the seed-beds and in the field. Both these diseases were
recorded from other localities, but not to the same extent. Consider-
able damage was done by Phytophthora to the stalks of tobacco
plants in the field at the Besoeki Experiment Station. Black rust
(Bacillus pseudozoogloeae) occurred at Deli. Mildew [Ozdiwm sp.]
was again very prevalent at the Vorstenland Experiment Station,
its extremely rapid spread being particularly noticeable. Mosaic
disease was reported from the Besoeki Experiment Station, the
shoots of topped plants being particularly lable. Two abnormal
conditions, ‘krepoh’ [leaf curl] and ‘kroepoek’, which are not
described, also caused considerable losses.

Tea. Mild attacks of Pestalozzia, Laestadia, Hypochnus theae,
Corticium javanicum, Capnodiwm, Thyridaria tarda, &e., were
recorded from the tea plantations of Java and Sumatra. The
damage caused by red rust (Cephalewros virescens), the most formid-
able vegetable parasite of tea in Java, was in some districts con-
siderable. Root diseases caused by various fungi (Rosellinia,
Armillaria, Ustulina zonata) are found in gardens at high eleva-
tions, and the root disease problem is a serious one on the east coast
of Sumatra.

Coco-nut. Pestalozzia was prevalent in one or two districts,
and a leaf disease, the cause of which is not specified, was recorded
from the province of Menado.

Corree. The incidence of the cobweb disease (Hypochnus) was
higher than in previous years. Mottling of the leaves of young
Robusta coffee trees occurred on a large scale in one estate. Pink
disease (Corticiwm salmonicolor) and brown root disease [Fomes
lamaoensis| were also reported, the latter being common on freshly
cleared land.

Maize. Downy mildew (Sclerospora javanica) was prevalent in
most districts, but only in a few instances were the losses heavy.
In the province of Pasoeroean the late planted ‘sawah’ maize was
severely attacked by this disease.

Orn Patm. The crown or ‘ juvenile’ disease [see this Review, i, 1,
p. 20] was again very prevalent. The disease never ends fatally,
but the development of the trees is arrested, and they remain in
a backward condition. It has now been ascertained that trees
above five years old are also liable to attack, so that the term
‘juvenile’ is scarcely applicable. The cause of the disease is not
known, but a physiological origin is indicated. A case of bud rot
was reported from Besoeki.

GROUND-NUT (Arachis hypogaea) was severely attacked by slime
disease (Bact. solanacearwm) in all districts. In one case the loss
amounted to 15 per cent. Leaf curl occurred in the Kediri province,
and is attributed by the natives to a sudden rainy period following
a prolonged drought.

CINNAMON (Cinnamomum burmanni) was attacked by bark or
stripe canker (Phytophthora cinnamomi Rands) at an experiment
station on the west coast of Sumatra.

Cincuona. Pink disease (Corticiwm salmonicolor) occurred on
young ‘ Ledger’ seedlings after an attack of Helopeltis, as well as
on older plants. Cinchona roots are liable to attack both by
Armillaria and by a species of Rosellinia, and the mycelia of these

A 2

10

fungi are frequently visible on the diseased parts. There are many
cases of root disease, however, in which the most striking symptom
is the decay of the cortex. Pressure on the damaged tissue causes
moisture to exude, and the diseased parts emit a foul smell. The
cause appears to be unknown. Stem rust and canker continue to
occur, while ‘mopog’ (Moniliopsis aderholdi) is reported from
various estates.

Amongst the diseases recorded on various minor crops were leaf
curl on Phaseolus mungo and Vigna sinensis, and Bact. solanacearum
on soy-beans.

Departmental Activities: Botany.— Journ. Dept. Agric. S. Africa,
iv, 4, p. 306, 1922.

Downy mildew, due to Sclerospora graminicola, has occurred for
the last two seasons on Sudan grass (Sorghum sudanense). The
crop in a field which became affected with the disease after the
second cutting had a scorched appearance,and the leaves were marked
with long, narrow, at first yellow or reddish, and finally dark
brown, streaks or patches, covered with a fine, white down con-
sisting of the conidia of the fungus. The affected areas appear to
spread from the lower to the upper leaves and from the apex to the
base of individual leaves. In other countries, especially in India,
S. graminicola occurs on several important cereals, and while at
present the disease is not a serious one in South Africa, it may,
under suitable conditions, become very troublesome, and it should
therefore be kept under close observation.

Regulations to prevent the introduction of potato wart disease
(Synchytriwm endobioticum) with imported seed have been in force
in South Africa for the last ten years, but it now appears that the
disease had been introduced in certain areas before they were
applied. Its occurrence in the Impendhle Division, Natal, has
recently been reported, while a similar report from the Queenstown-
Cathcart area awaits confirmation.

SmitH (EK. F.). Fasciation and prolepsis due to crown gall.—
Phytopath., xii, 6, pp. 265-269, 5 pl., 1922.

The author has succeeded in demonstrating that fasciation can
be produced experimentally by inoculating the crown gall organism
(Bacterium tumefaciens) into the leaf axils of Nicottana, Pelar-
gonium, Ricinus, Brassica, and Tropaeolum, and suggests that
many other fasciations may be due to the penetration of foreign
organisms into the growing point.

In the striking case which is fully illustrated by photographs,
a young nasturtium plant was inoculated through needle pricks in
a leaf axil. The fasciated shoot (shown as it appeared a month
later) was the only axillary shoot that developed. It arose from
a dormant bud along with the growth of the tumour resulting from
the inoculation. This was the only successful case out of fifteen
nasturtiums inoculated ; apparently the needle must enter the actual
dormant bud, which is not always easy to attain. In the rest, the
shoot which usually developed from the inoculated axil (mone of
the other axils gave shoots) was not fasciated. It was, however,
abnormally vigorous in growth in several cases, and rapidly gave

ee

11

rise to secondary, tertiary, and even quaternary shoots within a
period of two months, from buds that under normal circumstances
would have remained dormant. This forced growth is compared
with that which occurs in peach yellows, and is explained on the
supposition that the growth of the tumour at the base of the shoot
stimulates the movement of water and nutrients in this direction.
Continual growth of the tumour, however, effects an invasion and
compression of the vascular tissues at the base of the shoot, with
the result’that the latter wilts. At an early stage of this compres-
sion, the downward movement of elaborated foodstuffs from the
axillary shoot would very likely be interfered with sufficiently to
act as a further stimulus to its growth. Tests for starch showed
a marked accumulation in the cortex, pith, and medullary rays of
these shoots, as would be expected if the downward flow of elaborated
nutrients were checked. It is suggested that the proximate cause
of the forced growth in peach yellows must be the same, namely
the stimulus of excessive amounts of water and foodstuffs acting
locally as the result of phloem injury.

Benorst (J.) & Battty (P.). Moyens de combattre le piétin des
céréales. [Control measures against foot rot of cereals. |—La
Vie agricole, xi, 40, pp. 266—268, 1 fig., 1922.

The authors report that their previous investigations indicated
that one crop of wheat immediately succeeding another is seldom
attacked by foot rot (Ophiobolus graminis [O. cariceti| and Lepto-
sphaeria herpotrichoides), whereas infection almost always occurs
on soil which carried wheat two years previously. The longer
period between crops appears in some way to favour the disease.

Experiments in the control of the disease were carried out on
autumn wheat of the Geffroy variety, the trial crop, sown on
8th November, 1921, having been preceded by wheat. An application
of stable manure, which is stated to promote the development of
foot rot, was given, together with 400 kg. per hectare of super-
phosphate. The field was divided into six plots, which were treated
as follows: (1) control; (2) sprinkling of the stubble, before
ploughing, with a 4 per cent. solution of iron sulphate; (3) 400 kg.
per hectare of iron sulphate mixed with the soil by ploughing ;
(4) sprinkling on 9th March, 1922, with a 4 per cent. solution of
iron sulphate ; (5) sprinkling on the same date with a solution of
sulphuric acid; (6) 600 kg. per hectare of chloride of potassium
spread in January.

The control plot was slightly attacked by foot rot, but owing to
the drought, and to the fact that wheat immediately succeeded
wheat, the damage was not severe. The percentage of infection
was considerably reduced both by sprinkling the stubble with iron
sulphate, and by mixing this in at ploughing time. Very slightly
less favourable results followed sprinkling with iron sulphate in
the spring. Excellent effects were produced by spreading chloride
of potassium and by sprinkling with sulphuric acid. It is uncertain
whether the marked reduction of infection in the two latter cases
was due to the caustic action of the minerals or to their fertilizing
powers.

12

SmitH (C. O.). Pathogenicity of the Olive knot organism on
hosts related to the Olive. Phytopath., xii, 6, pp. 271-278,
2 pl., 1922.

The pathogenicity of Pseudomonas savastano: E. F. Smith on the
olive has been fully determined, but hitherto negative results were
obtained in the various attempts to inoculate plants more or less
closely allied to the olive.

The present paper deals with inoculation experiments extending
from 1919 to 1921, and carried out on the olive (Olea ewropea),
Fraxinus velutina, F. floribunda, Adelia acuminata, Ligustrum
ovalifolium, Chionanthus virginica, Osmanthus fragrans, Osman-
thus aquifolium, Vinea, Thevetia nereifolia, Nervum oleander,
Coprosma baueri, Carissa grandiflora, Chrysanthemum frutescens,
Elaeagnus angustifolia, lilac, jasmine, and several species of
Prunus. Typical artificial knots were produced only on Adelia, both
species of Frazinus, and jasmine. Definite lesions were produced
on Osmanthus aquifolium and Chionanthus, and small knob-like
growths developed on Ligustrum in one series of tests. The galls
produced on Adelia, Fraxinus, and jasmine were smaller than those
on the olive, with the possible exception of some on F. floribunda.
They appear to reach their maximum size in three or four months,
after which the tissue gradually dies. In the olive this process is
of longer duration.

Infection seems to be restricted to plants allied botanically to the
olive, especially those of the family Oleaceae. The olive knot
organism is characterized by the production of masses of bacteria
in definite cavities within the hypertrophied tissue of the olive.
It differs herein from the galls of Bacterium tumefaciens on various
hosts, where very few organisms are present in the hypertrophied
cells. Ps. savastanot is further differentiated from Bact. twme-
faciens by its limited pathogenicity.

MacInnes (JEAN). The growth of the Wheat scab organism in
relation to hydrogen-ion concentration.—P/ytopath., xii, 6,
pp- 290-294, 1 fig., 1922.

A strain of Fusariwm isolated from scabby wheat in Minnesota
was found to be capable of growing in nutrient media ranging from
P,; 3-0 to Py 11:7. This exceptionally wide range of tolerance is
compared with the published figures for a number of other patho-
genic organisms, the authority in each case being given. The
Fusarium strain in question has been found to be capable of
attacking a very large number of hosts, and further work with it
will be published elsewhere.

KuLkarnr (G. 8.) Conditions influencing the distribution of
grain smut (Sphacelotheca sorghi) of Jowar (Sorghum) in
India.— Agric. Journ. India, xxvii, 2, pp. 159-162, 1922.

In a previous publication (Pusa Bull. 78, p. 13) the author sug-
gested, on the evidence obtained from germination studies of the
spores of Sphacelotheca sorghi, that temperature had an important
bearing on the distribution of the disease. Sorghum is usually
sown in India in June-July, with an average temperature of 21° to
30° C., which is favourable for the germination of the smut spores,

ett

13

but below the optimum for the germination of the grain. In
certain areas, however, e.g. the Indo-Gangetic plain, the temperature
at sowing time is 30° to 40° C., which is too high for the spores to
germinate, but favourable for the germination and rapid growth of
sorghum ; the disease in these regions is scarce. In pot experiments
carried out at the Mycological Laboratory at Poona, pots sown with
infected sorghum and incubated at 40°C. for three days showed no
infection of the seedlings, while in other pots incubated at 25°C.
the amount of infection varied from 50 to 60 per cent. This clearly
shows that temperature is a limiting factor to infection by this
smut. A confirmation of this conclusion was also supplied by field
experiments carried out by sowing seed mixed with spores in 1918
and 1920 at Pusa, and at the Government farms at Larkhana and
Jacobabad in Sind, similar sowings at Poona serving as a control.
The results, full details of which are given, were particularly
definite at Jacobabad in 1920, where, with a temperature of 36° to
40° C. at sowing time, there was no smut, against 65 per cent. at
Poona where the temperature was only 25° C.

Hursu (C. R.). The relation of temperature and hydrogen-ion
concentration to urediniospore germination of biologic forms
of stem rust of Wheat.— Phytopath., xii, 8, pp. 353-361, 7 figs.,
1922.

Two biologie forms of Puccinia graminis of wheat, collected in
California and France respectively, and differing in their parasitic
behaviour, showed considerable differences in germination response
to temperature and hydrogen-ion concentration when uredospores
of the same age, grown under similar greenhouse conditions on
Little Club Wheat (which is susceptible to both forms), were used.
Temperatures of 10°, 20°, and 30° C. were used, and a Py, range of
from 2-5 to 8-0. The form more limited in its host range (that sent
from France) was also more restricted in tolerance of extremes of
hydrogen-ion concentration and temperature. The differentiation
of biologic forms is not entirely dependent on their parasitic be-
haviour on certain plants. At least some biologic forms apparently
possess individual physiological characteristics demonstrable by
physical and chemical means. The possession of such characteristics
alone may be sufficient to establish them as definite taxonomic
entities.

HuncerrorpD (C. W.). The relation of soil moisture and soil
temperature to bunt infection in Wheat.—P/ytoputh., xii, 7,
pp. 3387-352, 5 figs., 1922..

The infection of the soil with wind-blown spores of Z'iletia
tritici has been known for a number of years to result in smutted
crops in the Pacific North-West region of the United States. This
infestation does serious damage, and renders control very difficult.

Soil temperature and soil moisture have been proved in recent
years to be important factors in infection by fungi. Observations
made at Idaho have shown that, on contaminated soils, the amount
of soil moisture at planting time may have a very marked effect on
the amount of bunt in the resulting wheat crop. Experiments
were carried out to determine this relationship more exactly.

14

Wheat was grown at Moscow, Idaho, in six containers filled with
bunt-contaminated soil, varying in moisture content from 8 to 32
per cent. at the time of planting, and with a ‘ moisture equivalent ’
of 27-2 [cf. Briggs and McLane, Proc. Amer. Soc. Agron., ui, p. 138,
1911]. The percentage of bunt increased progressively to 100 per
cent. infection as the percentage of soil moisture increased. A
repeat experiment at Nez Perce, Idaho, gave similar results.

Greenhouse experiments in which both moisture and temperature
were controlled showed that low soil temperature (9° to 12°C.) and
a fairly high percentage of moisture in the soil (about 22 per cent.
with a moisture equivalent of 20-7) are both favourable to infection.
An exceedingly high percentage of moisture, however, seemed to
inhibit infection. A small amount of infection took place even °
when the temperature was as high as 25° to 28° C.

Preliminary experiments appear to indicate that bunt spores lose
their power to infect rather rapidly, since not more than 43 per cent.
infection resulted from artificially infected soil sown after the lapse
of a month.

Pevtier (G. L.). A study of the environmental conditions in-
fluencing the development of stem rust in the absence of an
alternate host. I. The viability of the urediniospores of
Puccinia graminis tritici Form III.—<Aygric. Exper. Stat.
Nebraska, Res. Bull. 22, 15 pp., 3 figs., 1922.

In order to determine with accuracy the viability of the uredo-
spores of stem rust of wheat under controlled conditions, the author
subjected uredosori of approximately the same age on detached
wheat seedling leaves to various combinations of constant tempera-
tures and relative humidities. Ordinary bacteriological incubators
were eniployed for temperatures of 25° and 30° C., while for lower
temperatures a special apparatus [which is described in detail] was
devised. Constant relative humidity was maintained in each
chamber by means of sulphuric acid solutions. The experiments
extended over a period of sixteen weeks.

The method of procedure was as follows: Some 2,000 Little Club
Wheat seedlings were inoculated with two weeks old* material of
Puccinia graminis tritici Form II from a stock culture supplied
by Stakman, in a greenhouse free from other rusts, a composite
inoculum being obtained by shaking the spores from the sori on to
a glass plate. The inoculated plants were incubated at a constant
temperature of 25° C. for forty-eight hours, after which they were
placed in a controlled-temperature greenhouse for twelve days at
a mean temperature of 24°C. The infected leaves were then cut
off and some thirty leaves were placed in each moist chamber. The
moist chambers were in sets of 11, each set forming a series of
from 0 to 100 per cent. relative humidity at approximately 10 per
cent. intervals. One such set was placed in each temperature
chamber, the temperatures used being 5°, 10°, 15°, 20°, 25°, and
30° C. No germination of the uredospores occurred at 30° C.,
while at 25°C. germination took place only at the medium relative
humidities. The maximum duration of viability (five weeks) at
this temperature occurred at the relative humidity of 49-0 per cent.
At 20°C. the spores were viable for one week at 100 per cent.

15

relative humidity, and for eleven weeks at 49-0 per cent.; with
each succeeding drop in the relative humidity below 49-0 there was
a decrease in the percentage of germination and the duration of
viability. At 15° C. the uredospores were viable for longer periods
at all humidities than at 20°C., but the duration of viability was
again longest at relative humidities of 49-0 to 60-7 per cent. (ten
weeks). At 10°C. the spores gave a higher percentage of germina-
tion, and were viable for longer periods at nearly all humidities
than at 15°C.; fairly high percentages of germination occurred at
the end of the sixteenth week at the relative humidities of 38-0,
49-0, and 70-4 per cent. At 5° C. the viability of the spores at the
medium humidities was still fairly high at the conclusion of the
experiment, but at relative humidities below 38-0 per cent. the spores
were not viable for such long periods as at 10°C. Somewhat
peculiar results were obtained at the relative humidity of 10-5 per
cent. at all temperatures below 25°C., a lower percentage of ger-
mination occurring at this point than at the relative humidities of
0 and 21-5 per cent.

The results of infection tests corresponded as a rule with those
of the germination trials. Few or no infections were obtained

with any inoculum showing less than 10 per cent. of germination.

As the percentage of germination decreased from week to week, the
germ-tubes became shorter and narrower, and their protoplasm less
dense. The use of such a comparatively weak inoculum resulted
in the production of hypersensitive flecks on the leaves, indicating
that, while the spores were capable of germination and of pene-
trating the tissues, the resistance offered by the host cells was
greater than the fungus could overcome.

The writer’s field experiments at Lincoln support the general
consensus of opinion on the viability of the uredospores of stem
rust, namely that the latter do not overwinter in the North. Rust
epidemics were started in the autumn and the uredospores germi-
nated readily until January, but not later. The results of the
experiments reported above show that down to certain temperatures
the uredospores are viable for long periods at the prevailing relative
humidities encountered in the tield during the autumn in the
winter wheat belt. It is further clearly demonstrated that at
constant temperatures somewhat below the average prevailing
during the summer in the South, the uredospores are not viable for
any length of time at any relative humidity. The mortality of the
free uredospores, extremely high at all times, is greatly increased
by the absence of suitable conditions for infection.. It therefore
seems safe to assume, in view of the brief duration of such con-
ditions, that only a small proportion of the countless number of
spores produced actually infect the host.

Stone (R. E.). Leaf scorch or mollisiose of the Strawberry.—-
Phytopath., xii, 8, p. 375-380; 3 figs., 1922.

Leaf scorch or mollisiose is very prevalent in parts of Ontario
and the United States. The first symptoms in new attacks appear
on the leaves in May in the form of irregular purple blotches, 4 to
2 in. in diameter. Purple stripes may be present on the petioles
and flower peduncles. The blotches gradually turn grey and

16

coalesce, and in time the whole leaf may be involved. By July or
August the beds frequently present a scorched appearance. The
following spring the disease appears early. The diseased plants do
not winter well, and the crop may be very short the second year.

Varietal susceptibility is very marked. The most susceptible
varieties appear to be Clyde, Glen Mary, Doctor Burrill, and
Pokomoke, the remaining common yarieties being moderately or
slightly susceptible.

An examination of the older portions of leaf blotches and diseased
petioles reveals the presence of dark acervuli filled with hyaline
bicellular spores belonging to the fungus Marssonia potentillae
(Desm.) Fischer. The fungus overwinters in the leaves and pro-
duces conidia in the spring. An ascigerous stage, agreeing with
descriptions and specimens of Mollisia earliana (E. & E.) Sace.,
may be found on the more exposed leaves from late April to June.
The conidia of M. potentillae are often present on the leaves, simul-
taneously with the ascocarps of M. earliana, and cultures from
single ascospores have given the Marssonia stage.

Full descriptions of both the stages are given and also their
synonymy. Inoculations with pure cultures bearing conidia were
successful.

The disease can probably be controlled by the measures applicable
to leaf spot (Mycosphaerella fragariae).

Hemmi (T.). On the occurrence of Mycosphaerella wilt of Musk-
melons in Japan.— Phytopath., xii, 8, pp. 394-397, 1922.

The presence of Mycosphaerella citrullina in both the perithecial
and pyenidial stages is recorded on diseased musk-melons in Japan.
The symptoms of the disease and characters of the fungus agree
with those previously described in America. The pyenospores are
hyaline and mostly bicellular, but may be continuous or with two
or three septa. The writer was recently informed that the fungus
had also been found on the leaves and vines of a species of gourd
(Lagenaria vulgaris var. gowrda) in the Shizuoka Prefecture.

Sxvusez (V.). Plétzliches Absterben der Obstbaiume. [Sudden
death of fruit trees.|—Allg. Weinzeit., xxxix, 34, pp. 153-134,
1922.

During the spring of 1922 great numbers of young fruit trees,
chiefly apples, in all the fruit-growing districts of Carinthia [Tyrol]
were suddenly killed off just when beginning to bloom. To the
naked eye there were no signs of disease or mechanical injury on
the trees. The phenomenon was assumed to be connected with the
abrupt alternations of temperature between the abnormally hot
summer of 1921 and the severe winter of 1921-22. Specimens of
the affected material have been examined, and although the final
results of the investigation will not be announced until later, a
preliminary report is already available.

The typical symptoms of frost injury could not be detected either
in the wood or cortex. Occasional brownish discolorations were
observed in the phellogen and in that part of the conducting cells
of the phloem bordering on the cambium, where the cell-walls were
also swollen at intervals, These symptoms, however, were not

17

present in all the branches. The cambium was usually dead, the
formation of wood having ceased from the previous autumn with
the exception of a few, isolated, spring wood cells. The pith was
discoloured only in places. :

These investigations, together with the meteorological conditions
referred to above, suggest the following conclusions. The trees were
suffering in the first instance from the abnormal drought of the
summer of 1921, which principally affected the tissues of the cam-
bium. This water-shortage was intensified by the excessively low
temperatures of the following winter, which extended into the soil
to a depth of one metre. As the result of the protracted plasmo-
lysis of the living cells thus brought about, the latter were unable to
meet the demands of the newly-circulating sap in the spring and
the development of shoots and blossoms stopped abruptly. Hence
the sudden death of the trees was only indirectly due to the coid,
the proximate cause being the exhaustion of the water-supply.

Rankin (W. H.) & Hockey (J. F.). Mosaic and leaf curl (yellows)
of the cultivated red Raspberry.—Phytoputh., xii, 6, pp. 253-
264, 1922.

This is a more detailed account: of the author’s investigations
referred to in a previous abstract [see this Review, i, 7, p. 218].
One or other of the two diseases is stated to be probably present in
all the larger small-fruit districts of the northern United States
and Canada. The ‘running-out’ of varieties, especially the Marl-
boro and Cuthbert, and the marked decline in acreage in many
districts have been attributed to them.

The leaf curl has many points of similarity to potato leaf roll,
and raspberry plants affected with this disease show a necrosis of
certain elements of the phloem and pericycle resembling potato
phloem-necrosis.

A list of thirty red and purple varieties of raspberry which have
been observed affected with mosaic is given. An outwardly similar
disease is also common on some cultivated varieties of black rasp-
berries. Leaf curl has been seen on the wild Rubus strigosus, the
ornamental R. phoenicolusius, and an unknown variety of black

raspberry.

Girona (C. D.). Ganoderma sessile Murrill.— Bol. Minis. Agric.
Nacién (Buenos Aires), pp. 236-239, 2 pl., 1922.

Considerable damage is caused to various fruit and forest trees
in the Argentine by Ganoderma sessile Murrill, which has been
found in one plantation on Prunus armeniaca, P. domestica, Pyrus
conmunis, Ficus carica, Punica granatum, Robinia pseud-acucia,
Gourliea decorticans, Casuarina stricta, Eucalyptus globulus,
Tipwana tipa, &e. Infection is caused either by the mycelium,
which spreads from diseased to healthy roots, or by spores falling
on to wounds or lesions on the exposed roots or base of the trunk.

Severely attacked trees, and all sporophores, should be removed
and burnt. In limited attacks the affected parts should be excised
and the wound disinfected. In new plantations the application of
manure should be avoided, and care must be taken not to wound
the young plants. In suspicious cases the roots may be treated

A 3

18

before planting with formalin or with 1 in 1,000 corrosive sublimate.
Stakes for young trees should be disinfected with copper sulphate,
formalin, or hot tar. A period of three years should be allowed
to elapse before replanting in infected soil. Humidity promotes the
development of the fungus, and care should therefore be taken to
drain the water from the collars of the trees.

Csrre(A.). Die Wirkungen von Uspulun, Formalin, Kupfervitriol, -
Schwefelkalkbriihe und Klorol auf die Keimfahigkeit des
Zuckerribensamens. |The action of uspulun, formalin, copper
sulphate, lime-sulphur, and klorol on the germination of the
seed of Sugar Beet.|—Kisérletiigui Kézlemények, xxiv, 1921.
[Abs. in Zentralbl. fur Agrikulturchemie, li, 8, p. 207, 1922.]

The vitality and germinative power of the seed of sugar beet are
increased by the use of uspulun, copper sulphate, klorol, formalin,
and lime-sulphur, in the order given. These preparations are
recorded as being of practical and scientific value, not only on
account of their fungicidal properties, but also because of the
stimulus which they afford to germination.

Buter (O.) & Smirn (T. O.). On the use of acetates of copper as
fungicides.— Phytopath., xii, 6, pp. 280-289, 1 fig., 1922.

Two acetates of copper are used as fungicides, the normal or
neutral acetate of copper Cu(C,H,O,),.H,O, and the basic acetate
of copper Cu(C,H,O,)Cu0.6H,O, the former containing 31-8 per
cent. of metallic copper and the latter 34-4 per cent. There is
ample evidence that the acetates of copper compare favourably with
Bordeaux mixture in fungicidal properties. Both the acetates
(‘verdets’) have been used by vine-growers for the last thirty years
in the south of France and Italy, with excellent results, but in
America they are very little known. The acetates of copper are
non-toxic to the plants on which they are used, and form less
conspicuous spots than the cuprammoniums (ammoniacal copper
compounds).

The adhesiveness of the acetates of copper depends on the degree
of decomposition which takes place during drying, and on the
length of time elapsing between application and the first washing
rain. Basic acetate is more adhesive than neutral acetate, and
decomposes more rapidly on exposure to air. Neutral acetate,
however, is more easily obtainable than basic acetate, and its
adhesiveness can be greatly increased at a small cost by the addition
of 0-05 per cent. of gelatine. At the end of forty-eight hours the
adhesiveness of neutral acetate plus gelatine is virtually equal to
that of basic acetate alone, and at subsequent periods it is only
slightly lower. The same proportion of gelatine added to basic
acetate also produces an increase of adhesiveness chiefly during the
first day of drying, i.e. the time when the maximum of adhesiveness
is required.

The writers propose the following formulae, using a stock solution
of the acetate made by dissolving the substance in cold water at
the rate of 1 lb. per gall. Formula 1: water 49 galls., basic acetate
of copper (stock solution) 1 gall. (or for a stronger solution 46: 4).
Formula 2: water 48 galls., basic acetate or neutral acetate (stock

19

solution) 1 gall., gelatine (stock solution) 1 gall. (or for a stronger
solution 45:4:1). The stock solution of gelatine is made by dis-
solving 4 oz. of gelatine in 5 quarts of hot water, and should not
be above 40° C. when added to the acetate. The weaker strengths
given above are intended for use in place of a cuprammonium spray,
the stronger where a colourless fungicide is required in place of
Bordeaux mixture and of the same fungicidal value.

HENNING (E.). Om betning mot Stinkbrand (Tilletia tritici), Stra-
brand (Urocystis occulta), och Hardbrand (Ustilago hordei).
II. Bidrag till formalinbetningens teknik. [Disinfection
against bunt (Tilletia tritici), flag smut (Urocystis occulta), and
covered smut (Ustilago hordew). II. Contribution to the tech-
nique of disinfection with formalin. ]|—Meddel. Centralanst. for
forséksvisendet pa jordbruksomrddet, 231, 36 pp., 3 figs., 1922.

The preparations in general use in Sweden for the control of
bunt and other smuts are copper sulphate, uspulun, and formalin.
The two first named have various drawbacks. Both are poisonous,
and the residue of the treated seed therefore cannot be used for
feeding. The application of copper sulphate is tedious and com-
plicated, and its danger to seed damaged by threshing is not entirely
removed by the addition of milk of lime. The poisonous consti-
tuents of the mercury chlorophenol contained in uspulun still
adhere to the seed even if the latter is washed after treatment.
A further disadvantage of uspulun is that the effective principle is
absorbed by the seed at a quicker rate than the water, so that a
certain quantity of the fungicide has to be added to maintain the
proper concentration during repeated use.

The author has conducted numerous experiments with a view to
modifying the technique of formalin disinfection, the one objection
to which is the reduction of germinative power during storage.
The results showed that washing the seed in water after treatment
with formaldehyde at various concentrations lessened this injury.
Ordinary rinsing is usually sufficient, but if a very high concentra-
tion of formaldehyde is used, or if the varieties are particularly
susceptible to injury, then the seed should be immersed in water.
Further tests showed that seed rinsed after treatment and dried in
a cellar germinated to the extent of 87-7 per cent. even when kept
for eleven months before sowing. The results of comparative tests
with germisan, formaldehyde, and hot water showed no appreciable
difference between the two former methods. Germisan has the
disadvantage of being extremely poisonous. The percentage otf
seed which germinated after treatment with hot water was slightly
below the other two methods and the control.

Formalin is comparatively inexpensive, the quantity of diluted
solution required (80 litres) for the disinfection of 100 kg. of grain
costing only Kr. 1.20 |about 1s. 5d.]. When the treatment is
carried out with !00 kg. lots, each further 100 kg. of grain requires
only 10 litres of the solution to replace what has been used. For-
malin does not lose its strength after repeated use. Immersion is
a far more reliable method of disinfection than sprinkling.

The concentrations recommended are 0-15 per cent. formaldehyde
for rye and wheat, and 0-2 per cent. for barley and oats. The

20

temperature of the solution should not be less than 12° to 15°C.
The grain should be poured slowly into the solution (which should
stand 10 em. above the grain) and stirred with a blunt wooden
shovel. The subsequent washing in water is carried out as follows:
Three barrels are used, one raised above the others. The steeping
takes place in the raised barrel (#) which is furnished with a tap.
After twenty minutes the solution is drawn off into the left-hand
lower barrel (5), (a) being filled with water for rinsing. After five
to ten minutes the rinsing water is drawn off into the right-hand
lower barrel (c). The solution in (6) can then be poured back into
(a) and used again. If the process is carried out in the open the
third barrel is superfluous, the water simply being run off on to the
ground. Treated in this way the grain may be kept for a week or
more before sowing.

A comprehensive bibliography, containing seventy references, is

appended.

KREUZPOINTER (J.). Einiges tiber das Beizen der Samen. [Notes
on seed steeping. |— Wequweiser im Obst- und Gartenbau, v, 1922.
[Abs. in Zentralbl. fir Agrikulturchemie, li, 8, p. 208, 1922.

Uspulun used as a seed steep on old seed of celery and mangoids
stimulated germination while a steep of corrosive sublimate retarded
it. Anthracnose of kidney beans [Colletotrichuim lindemuthianum |
was controlled, and the yield increased fivefold. Celery rust was also
suppressed. In both cases, however, the treated crop later became
infected from neighbouring diseased plants. The beds should
therefore be isolated as far as possible.

WIELER (A.). Die Beteiligung des Bodens an den durch Rauch-
siuren hervorgerufenen Vegetationsschaden. [The rdéle of
the soil in the injuries to vegetation produced by smoke
acids. |—Zeitschr. fiir Forst- und Jagdwesen, liv, 9, pp. 584-543,
1922.

The prevailing opinion that the injuries caused to vegetation by
the fumes of acid gases develop almost entirely in the leaves cannot
be unreservedly accepted. The author’s observations and investiga-
tions in the forests of Stolberg on the Rhine and Clausthal in the
Harz Mountains, both of which have suffered severely from smoke
injury, have convinced him that the removal of lime from the soil
by acid gases is primarily responsible for the protracted enfeeble-
ment and final death of the trees. Experiments showed that the
withdrawal of lime from the soil caused the formation of bare
patches, on which even the common weeds of the district would not
grow. After the application of lime to the affected patches, how-
ever, it was possible to grow broad-leaved trees and conifers. It
has also been shown by comparative investigations that the with-
drawal of lime takes place on a more extensive scale immediately
under trees suffermg from smoke injury. The absence of grass
under trees in the parks and suburbs of manufacturing towns is
due, not to the shade cast by the branches, but to a deficieney of
lime in the soil under them. In the coal-mining districts of West-
phalia the author noticed large bare patches in fields, the site of

—— ee eS ee

21

which was formerly occupied by woods. The application of lime
removed all trace of these bare patches.

The root system is the first part of the plant to suffer from the
deficiency of lime, but the effects are rapidly communicated to the
aerial organs. Removal of lime also produces important modifica-
tions in the physical and biological composition of the soil, which
react on the development of the trees.

These and other investigations show that, in forests especially,
the influence of the acid gases on the soil, quite apart from any
direct action on the leaves, must be taken into consideration. In
cases of general debility, with no definite external symptoms, soil
disturbances may reasonably be suspected, while they are frequently,
as stated above, correlated with damage to the leaves.

Smoke injury may be combated to some extent by liming, but in
severe cases it may be necessary to convert the forests into pasture
and arable land, which are very much less susceptible than trees to
the action of the fumes.

LANGERON (M.). Un nouveau Sporotrichum malgache: Sporo-
trichum carougeaui Langeron, 1913, et remarques sur les
Sporotrichés. [A new Madagascar Sporotrichum: Sporo-
trichum carougeaui Langeron, 1913, and observations on the
Sporotricha. |—Bull. Soc. Path. exot., xv, 6, pp. 453-459, 2 figs.,
1922.

After a brief discussion of the characters and systematic position
of the genus Sporotrichum, the author describes in detail a new
pathogenic Sporotrichum discovered in 1910 in Madagascar by
Fontoynont and Carougeau. The fungus, which was isolated from
ulcers on the neck and armpit of a native child, differs macroscopi-
cally from other species of Sporotrichum by its dazzling white
colour which persists in the oldest cultures. The hyphae are sep-
tate, creeping, and 2-5 to 4 in diameter. The conidia are at first
elliptical, and measure 2 by 4 yu, afterwards becoming circular, and
attaining a diameter of 4 to 5y. They are produced at irregular
intervals, along the whole length of the hyphae, either singly or in
clusters, and may elongate and give rise, by a budding process, to
secondary conidia.

The cultures of S. carowgeaui exhibited a remarkable morpho-
logical uniformity, with no tendency to the production of Botrytis,
Graphiwm, or other forms such as Boulanger and Vuillemin observed
in cultures of Sporotrichuim and Rhinocladiwm. Yeast forms were
produced in abundance in cultures under certain conditions not yet
determined. Probably this is the form in which the fungus exists
in the tissues.

ELMER (O. H.). Mosaic cross-inoculation and insect transmission
studies.—Science, N.S., lvi, pp. 870-372, 1922.

It is generally believed that the mosaic diseases of the Cucurbi-
taceae, Solanaceae, and Leguminosae are transmissible, with few
exceptions, only to species within the same family. Cross-inocula-
tion experiments by the writer have shown, however, that these
three diseases are inter-transmissible.

_ Four petunia plants inoculated by inserting pieces of tissue with

22

mosaic from crookneck squash into wounds in the stem became
infected, while an equal number of controls remained healthy.
Hypodermic inoculation of four crookneck squash plants with juice
from tomato mosaic and four with juice from tobacco mosaic
resulted in infection in all cases. One tobacco and two tomato
plants inoculated with juice from mosaic crookneck squash leaves
also became infected. In another experiment the insertion of
mosaic crookneck squash leaf tissue into the midribs of five tobacco
plants resulted in complete infection. Only one of five tobacco
plants similarly inoculated with mosaic cucumber tissue became
infected. Three out of five tomato plants inoculated with mosaic
from catnip (Nepeta cataria). became intected.

Experiments with the cow-pea (Vigna catjang), which is suscep-
tible to mosaic under greenhouse conditions, showed that the disease
is transmissible by aphids, full infection occurring on seedlings in
insect proof cages into which aphids from mosaic plants were intro-
duced, while all the controls remained healthy. Numerous experi-
ments have also demonstrated that the mealy bug (Dactylopus sp.)
transmits the disease, especially in the case of cow-peas and soy-
beans. When mealy bugs from a mosaic crookneck squash plant
were transferred to 33 cow-pea seedlings they gave 100 per cent.
of infection. Identical results were obtained in the case of 38
cow-pea seedlings inoculated by means of mealy bugs from mosaic
infected eggplant. The transference of aphids from mosaic potato
to 36 cow-pea seedlings resulted in the infection of 28. Mealy
bugs were transferred from mosaic infected cow-pea to soy-bean
seedlings, a large percentage of which developed the disease. In
all the above experiments the controls remained healthy. The
tobacco plants and one tomato were also infected with mosaic from
crookneck squash through the agency of Dactylopus sp.

The writer is of opinion that mosaic infection is largely deter-
mined by the growth condition of the plant, unchecked, vigorous
development promoting infection. Successful cross-infections be-
tween members of different families are more readily obtained with
plants growing under favourable conditions than with those less well
situated.

NARASIMHAN (M. J.). The Areca koleroga work during 1921.—
Mysore Agric. Calendar, pp. 4-8, 1922.

The year under consideration was marked in Mysore by a re-
crudescence of the koleroga disease of areca palms [Phytophthora
arecae| due to the heavy rainfall during the later part of the season.
In five districts the number of trees sprayed against the disease
amounted to about 372,000, covering a total area of over 900 acres
as against 300 acres treated during the previous year. A fairly
successful attempt was made to induce all the owners of block
gardens to take up spraying, as it was believed that the disease
appeared virulently every year if only isolated lots in a block were
sprayed; in certain places where the disease had been virulent for
some years, the Pest Act was enforced.

Experiments carried out over several consecutive years with
a view to ascertaining the possibility of stamping out the disease
in particular areas gave satisfactory results. The Kerodi garden

23

showed no traces of the infection for three years after the cessation
of the treatment, in spite of being in close proximity to badly
‘infected areas ; in the fourth year, however, the disease reappeared
on a few trees, and has been increasing since then, but not with its
former virulence. After a few years of spraying the disease has
been completely stamped out in the Agumbe garden; during the
last eight years, following the cessation of the control work, not
a single tree has been attacked, notwithstanding the fact that the
garden is situated in an area of high rainfall, and in a locality
where koleroga is at its worst.

No change has been found necessary in the formula of the
spraying mixture as originally recommended by the Department
[Coleman. Diseases of the areca palm. 1. Koleroga, Mysore Dept.
Agric. Mycol. Ser. Bull., ii, 1910), except in the amount of soda
with which the resin is boiled; this quantity may vary from 4 to
1 lb. according to the nature of the soda. ‘Blighty’ Burgundy
mixture did not give satisfactory results. The present cost of
spraying 100 trees is from Rs. 2-12-0 to Rs. 3 [R. 1 = about 1s. 4d].

Futton (H. R.). Occurrence of Thielaviopsis paradoxa on the
cocoa-nut palm in Florida.—Phytopath., xii, 8, pp. 398-399,
1922.

Sections of a diseased trunk of a coco-nut palm from Florida,
examined in January 1922, showed extensive rotting of the ground
tissue of mature parts, resulting in large internal cavities. The
disintegrated part was dry and brittle, surrounded by a zone of
recently invaded tissue which was brown and water-soaked. Cul-
tures from the advancing margins of the decaying areas yielded
almost pure growths of an organism agreeing closely with the
description of Thielaviopsis paradoxa. he identity of the fungus
was confirmed by inoculating healthy pineapples with pure cultures,
which caused typical Thielaviopsis rot. T. paradoxa was readily
recovered in pure culture from the artificially infected pineapple
fruits and leaves.

The results of a series of tests indicated that 25°C. is the opti-
mum temperature for mycelial growth in this fungus. At 15° C.
there is distinct retardation, and at 10° C. visible development does
not occur in twelve days.

FunkKE (G. L.). The influence of hydrogen-ion concentration upon
the action of the amylase of Aspergillus niger. Reprinted
from Proc. Kon. Akad. Wetenschap. Amsterdam, xxv, 1-2,
3 pp., 2 figs., 1922.

The action of the amylase produced in large quantities by
Aspergillus niger does not appear to be unfavourably influenced
by a high hydrogen-ion concentration of the nutrient medium. It
was therefore assumed that the optimum concentration for the
action of this amylase would not be found to be the same as the
optimum for ptyalin, namely, an almost neutral or faintly acid
reaction.

Preliminary investigations were made, equal amounts of enzyme
solution from the nutritive liquid being mixed with buffer solution
and 0-16 per cent. amylum solution. The hydrogen-ion concentra-

24:

tion of this mixture was determined by the aid of colorimetric
indicators, and the rate of hydrolysis of the amylum by the iodine
reaction. It was found that there was no point of optimum action,
but a broad optimal zone extending from Py 3-5 to 5:5. No
apparent influence was exercised either by the concentration of the
amylase or the composition of the nutritive liquid. Amylase ex-
tracted from the mycelium gave the same results. The theory of
Michaélis, that the enzymes are ampholytes, is largely confirmed by
these results.

The dissociation constant of the acid of the amylase of malt
appears to be the same as for the amylase of Aspergillus, that of
the base being larger, namely, 5-76x107'!. Thus as acids the
two amylases are equally strong, as bases that of the malt is the

weaker.

Hopkins (E. J.). The effect of lactic acid on spore production of
Colletotrichum lindemuthianum.—P/ytopath., xii, 8, pp. 390—
398, 2 figs., 1922.

The author found that the addition of three drops of lactic acid
to 20 cc. of potato agar greatly increased spore-production in cul-
tures of the 6 strain of Colletotrichum lindemuthianum. In cultures
containing two drops of acid a few pustules were observed, while
the addition of only one drop caused no appreciable degree of
sporulation. Spore-production in this species appears to increase
with increase in hydrogen-ion concentration, while there is an
accompanying decrease in the amount of vegetative growth.

Brown (W.). On the germination and growth of fungi at various
temperatures and in various concentrations of oxygen and of
carbon dioxide.—Ann. of Botany, xxxvi, 142, pp. 257-283,
1922.

The object of the author’s investgations was to examine the
behaviour of fungi under similar conditions to those of fruit
storage. Of the two methods of fruit storage known—cold storage
and gas storage—the former is widely employed, while the latter
is still in the experimental stage. The temperature employed in
practice for cold storing fruits usually does not go below 2° to 3°C. ;
and for his experiments the author has taken 5° C. as his lowest
temperature except in a few eases. The gas storage method is
based on the retarding action of carbon dioxide on metabolic pro-
cesses. In practice, the maximum feasible concentration of this
gas is somewhat below 20 per cent., for the concentration of oxygen
in the atmosphere of the store has to be kept at a certain level so
as to avoid anaérobic respiration. In the experiments special atten-
tion has therefore been given to the concentrations admissible in
practice.

The work of other investigators in similar fields is touched upon
in the historical section of the present paper, and an account given
of the methods followed in the course of the experiments. The
results obtained indicate that the conclusion can be drawn that,
within very wide limits, variation of oxygen pressure has little
effect on the germination and growth of the ordinary fruit-rotting

4
#
4
¢

25

organisms such as Botrytis, Fusariwin, Alternaria, &c., no appreci-
able decrease in germination being shown until very low concentra-
tions of oxygen—about 1 per cent.—have been reached. Even
with a CO, concentration of 30 per cent., the oxygen content of air
would still be 14 per cent. Hence, in practice, variations in the
latter must be regarded as of negligible importance.

Carbon dioxide, on the other hand, retards the germination and
growth of fruit-rotting fungi. This action is most marked at the
lowest temperatures and in the weakest nutrient solutions, and is,
to a lesser degree, dependent on the density at which spores are
sown, greater density favouring retardation. Parallel series of
germination tests—one in water and the other in a turnip extract
made by extracting the juice of turnips boiled without any added
water, and then diluted with water to one-fifth strength—showed
that Penicillium glaucwm is the most insensible of the fungi tested to
CO,, the concentration required to stop germination in the nutrient
_ medium being 80 to 95 per cent., and in water over 30 per cent.
This compares with 50 per cent. and 20 to 30 per cent. respectively
for Botrytis cinerea, while Aspergillus repens required 40 per cent.
CO, in the nutrient medium to prevent it from germinating. The
time allowed for germination was seven days (the author considering
this period sufficient for assuming complete inhibition if no ger-
mination had taken place by then), and the temperature was 15°
to 18°C. In the case of Rhizopus nigricans, the spores of which,
in 50 per cent. CO,, showed universal germination, the germ-
tubes, instead of being long, straight, cylindrical, and of uniform
diameter, appeared as short, stunted structures, irregularly swollen.
This is attributed to the formation of ‘ giant cells’ (‘ Riesenzellen’)
due to acidity brought about by the high pressure of carbon
dioxide. On being brought back to normal atmospheric conditions,
these distorted germ-tubes resumed normal growth. This absence
of permanent injury was observed in all the fungi treated with
CO,, as they germinated with their usual vigour and produced
ordinary germ- “tubes as soon as they were placed in normal
atmospheric conditions.

The combined action of carbon dioxide and low temperature was
tested upon (a) germination of the spores, (b) rate of growth of
colonies on artificial media, (c) rate of growth of specific fungi on
certain fruits. It was found that the inhibitory action of carbon
dioxide is greatly increased by lowering the temperature. Even
with the very resistant Penicilliwm glaucum a 10°C. drop from
ordinary temperature, combined with 10 to 20 per cent. carbon
dioxide, slows down the rate of growth of the germ-tube 6 to 9
times. Most of the measurements, however, were done not on
germ-tube length, but on the diameter of plate colonies. It was
found that the amount of retardation of growth is greatest in the
earliest phases of growth and decreases. with time usually up to
a certain limit, but in some cases, at the higher temperatures, the
carbon dioxide cultures overtake and may even pass those in air.
This is due to partial neutralization by the carbon dioxide of the

‘staling ’ which in these cases is associated with a development of
alkalinity by the fungus.

As in the case of CO, action on germination, the retarding effect

26

of CO, combined with low temperature varies with different fungi,
in roughly the same order in both cases.

When inoculated into fruit the same general results were obtained,
but the additional factor due to the different degrees of parasitism
of the fungi tried had an effect on the results. For instance,
Botrytis is a weaker parasite on apple than Monilia, and one may
suppose that living apple tissue is a poorer nutrient for the former
than for the latter. All the results obtained are believed to be
covered by the statement that the carbon dioxide retarding factor
has greatest effect when the energy of growth is small. Hence one
would expect that Botrytis is more readily retarded than Monilia
on living fruit, and this is the case.

The general conclusion is reached that the gas storage method is
most effectively used in combination with the ordinary cold storage
method, and that it will give the best results when no attack of
the fruit has begun previous to storage, and when conditions are
such that a minimum of nutrient is available for spores on the
surface of the fruit.

Graphs and tables are given of the rates of growth of a number
of fungi at various temperatures and in various concentrations of
carbon dioxide.

Dickson (B. T.). Diseases of the Potato.— Fourteenth Ann. Rept.
Quebec Soc. Prot. Plants, pp. 67-105, 12 figs., 1922.

This is a somewhat popular account of the diseases of the potato
in Canada, reprinted from Scientific Agriculture. +The diseases
described are hopperburn, mosaic and mosaic dwarf, leaf roll, pow-
dery scab (Spongospora subterranea), blackleg (Bacillus atrosep-
ticus), wart (Synchytrium endobioticum), leak (Pythium de
Baryanum), late blight (Phytophthora infestans), wilt and stem
rot (Sclerotinia libertiana), seurf (Corticuwm vagum), early blight
(Alternuria solani), wilt and net necrosis (Fusariwm oxysporum),
scab (Actinomyces scabies), skin spot (Oospora pustulans), silver
seurf (Spondylocladium atrovirens), dry rot (Fusariwm spp.), and
black dot (Vermicularia varians).

The last-named is new to America. It was first discovered in
France by Ducomet in 1908, and named ‘ dartrose’, and was after-
wards found in Australia and South Africa. The symptoms of the
disease are a slight yellowing of the foliage, sometimes accompanied
by dwarfing, followed by the withering of the leaves, and the
development of minute, black sclerotia on the surface, especially of
the lower part of the stem. Sclerotia are also found lining the
inside walls of the vascular cylinder and covering the tubers. The
roots and rhizomes are also attacked. The mycelium is found
throughout the tissues, including the leaves when the latter bear
sclerotia. In the tubers it is confined to the outer layers and does
not cause serious damage. In the author’s cultures the spores were
slightly smaller than those described by Ducomet and the setae
longer, while the sclerotia were not closed pyenidia as he states.
Ducomet’s spore-measurements were 18 to 22 by 2-5 to 3 yw and the
setae 100 to 130 yz.

The fungus is stated to be also parasitic on tomato and Physalis
peruviana in France. The author has artificially infected the

-

27

former. The disease is only serious in so far as it weakens the
plants and thereby reduces the crop.

CREPIN (C.). Une maladie grave de la Pomme de terre dans le
nord dela Loire. [A serious Potato disease in the north of
the Loire Department.|—Comptes rendus Acad. Agric. France,
vii, 30, pp. 803-806, 1922.

A serious disease of potatoes has recently been observed in various
localities in the north of the Loire Department. The symptoms
appear towards flowering time, when the topmost leaves begin to
curl, followed by those of the middle and base of the stem. In
hot, dry weather the plants are killed in a few days, desiccation
beginning with the lower leaves, which droop down along the stem.
In dull or damp weather the plants may live for some time, their
curled leaves frequently leading to confusion with leaf roll or
leptonecrosis, from which, however, the present disease may be
distinguished by two main characteristics. The topmost leaves are
the first to be affected, and they become soft, flaccid, and drooping ;
whereas in leaf roll the leaves at the base show the first symptoms,
and they usually remain firm and upright. In cases where the
plants live for some time after attack, the stems and leaves gradually
lose their chlorophyll and assume a greenish-yellow tinge, while
the axillary buds develop into more or less swollen axes.

On pulling up a diseased plant it will be found that the stolons,
roots, and underground portions of the stem are attacked by a dry
rot. The cortex is easily detachable, leaving the central cylinder
exposed. Under the periderm may be seen a number of minute,
black sclerotia, situated around the medulla of the base of the stems
and even in the wood. They are also present on the stem up to
several centimetres above soil level.

On the tubers are grey or discoloured patches which also bear
sclerotia, smaller than those on the stem. ‘This disease of the tuber
was investigated by Ducomet in 1908, found to be due to the
previously undescribed fungus Vermicularia varians, and named
‘dartrose’ [see preceding abstract]. Since that time the disease
has not been reported in France, which suggests that the fungus
may be only a facultative parasite. In any case the damage caused
by it is extremely serious in the vicinity of Saint-Germain-Laval,
where all the fields are attacked, and not a single plant is immune.
The yield is considerably reduced and many of the tubers are soft.

It will be necessary to institute a series of experiments during
1923 to test the resistance of the better-known commercial varieties,
great care being taken to distinguish between what may be termed
‘flaccid ’ leaf roll and the true disease of that name.

LAcHAINE (O. W.). Sclerotial disease of the Potato.— Fourteenth
Ann. Rept. Quebec Soc. Prot. Plants, pp. 105-109, 6 figs., 1922.
During 1921 the writer found 10 per cent. of sclerotial disease
in a four-acre field of potatoes in New Brunswick, and 1 to 2 per
cent. in four other fields. A blackish zone was found extending
upwards from the soil for about five inches, giving the plants the
appearance of blackleg. The cortical tissues were easily removed
by rubbing. Three weeks later the outer necrotic tissues were

28

dried out and the leaves yellowed. Abundant sclerotia were found
in the place of the pith. After a month’s freezing, followed by
sterilization in mercuric chloride 1:1,000 and washing in sterile
water, cultures were obtained from the sclerotia. No apothecia
were observed.

Greenhouse experiments showed that the earliest signs of the
disease are patches of whitish mycelium on the outside of the
potato or tomato stem, at the point of infection level with the sur-
face of the soil. In damp weather profuse mycelial growth occurs,
with a subsequent development of external sclerotia, which are
whitish at first, afterwards turning black and falling to the ground.
The mycelium gradually penetrates to the pith, where rapid growth
takes place with the formation of the internal sclerotia.

Inoculations on potato and tomato plants caused the destruction
of the cortical tissue of the latter two inches above soil level, and
wilting of the plant. The tissues of one potato plant were destroyed
to a height of three-quarters of an inch, and half the circumference
of the stem; on another the mycelium spread no farther than the
tissues at the place of inoculation. .

The fungus cannot be certainly identified in the absence of
apothecia, but appears to be identical with Sclerotinia libertiana,
Fel. The only effectual control measures are the destruction of
diseased material and crop rotation.

LutMAN (B. F.). The relation of the water pores and stomata of
the Potato leaf to the early stages and advance of tip burn.—
Phytopath., xii, 7, pp. 805-333, 9 figs., 1922.

The type of tip burn here studied is that associated with hot,
dry weather and clear, brilliant sunshine, and is entirely distinct
from that due to leaf-hopper injury. The work was carried out in
Vermont, where leaf-hoppers are very rare.

Hydathodes have long been known to occur in the potato leaf,
but no accurate study of them has been made. They occur on all
margins, but are most frequently found toward the tip of the leaf.
In structure they are not unlike stomata; the guard cells are

larger, but otherwise identical, and they open and close in the same -

manner. The water cavity is larger, and opens directly on the
vessels of the marginal vein, which is very highly developed and
very characteristic.

Tip burn begins beneath the hydathodes, especially at the tips of
the leaflets, the palisade parenchyma under the openings turning
brown. The death of the tissues is probably brought about by
excessive transpiration leading to extreme plasmolysis, and it
proceeds backwards along the edges of the leaflet. .

Poisonous substances (e.g. borax) are capable of being absorbed
by the roots and producing a somewhat similar type of imjury to
that just described. In most cases of tip burn, however, the effect
of poisons is likely to be secondary, but at times it is undoubtedly
a primary factor.

The advance of tip burn into the leaf is explained as follows:
The marginal vein, which probably plays an important rédle in
equalizing the water-supply to all parts of the leaf, is liable to be
killed under the influence of heat and intense sunlight. The result

—

29

would be that the vein would not be able to supply water to pre-
vent the wilting and plasmolysis of the tissues towards the midrib.
Cells plasmolysed beyond a certain limit die, whilst those less
severely affected become yellowed owing to the destruction of
chlorophyll. Experiments showed that severing the marginal vein
in a number of places in hot, sunny weather led to tip burn.

The stomata are important in relation to the transpiration of
water, and were therefore studied. The number of stomata on the
upper side is much greater than usually supposed, the proportion
to the total number on the leaf varying from one-third on the
young leaves to less than one-fourth on the older ones. Tip burn
seems to have little effect on the stomata or tissues under them.

The author is inclined to distinguish another type of tip burn
with rather clearly defined edges, which is more of the nature of
a scorch, and appears to be the result of excessive sunlight, as it
may be reproduced in the laboratory with mirrors.

SHAPOVALOV (M.). Bhizoctonia solani as a Potato-tuber rot
fungus.— Phitopath., xii, 7, pp. 334-336, 1 pl., 1922.

Rhizoctonia solani has been found producing a tuber rot on
abnormal tubers of the varieties Netted Gem and Burbank in the
western United States. Only the abnormally elongated stem ends
of these tubers, and occasionally knobs and eye ends, appear to be
susceptible, a very peculiar jelly type of decay being produced.

The fiesh of the elongated stem ends is deficient in starch and
differs from the remaining tissues of the tuber by its watery and
somewhat translucent appearance. If uninfected these stem ends
shrivel up.

Tubers showing the jelly-like decay, carefully selected from
healthy plants, yielded only A. solani in culture. Affected tissues
in the first stage of the infection were nearly white, but as the
decay developed they turned yellow and brown. This Rhizoctonia
jelly rot does not usually advance beyond the elongated part of the
stem end, the decayed portion being ultimately sloughed off or
drying up and hardening.

Inoculations with R. solani on five abnormally elongated tubers
all gave successful infections. Although this fungus appears to be
responsible for jelly end rot in the present case, the possibility that
other organisms, especially species of Fusariwm, cause a similar
form of decay (as maintained by previous workers) is not excluded.

RICHTER. Der Einfluss von Rhizoctonia solani auf den Keimungs-
verlauf der Kartoffeln. [The influence of Rhizoctonia solani
on the germination of Potatoes.|—Nachrichtenbl. deutsch.
Phlanzenschutzdienst, ii, 3, pp. 19-20, 1922.

Investigations on the germination of potato tubers of the varieties
Wohltmann and Kaiserkrone, carried out at Landsberg in 1922,
showed a high degree of infection by Rhizoctonia solani—35 per
cent. in the case of Wohltmann and 40 per cent. in that of Kaiser-
krone. The small, dark brown or black nodules on the skin, after
swelling and becoming soft, sent out vegetative hyphae which
generally extended over the surface of the tubers, where they
formed a brownish network. In many cases this surface growth,

30

on reaching the newly-formed shoots, penetrated the latter, usually
near the erowing-point. Shoots thus infected turned brown and
died. In a few cases the hyphae penetrated the older portions of
the shoots first, generally from a lateral bud. The decay then
appeared as a brown. scutiform spot, which gradually encircled the
shoot and separated the upper, healthy part from the lower. The
decay spread from infected to healthy shoots.

This disease was generally fatal, but occasionally particularly
vigorous individuals managed to throw out new lateral shoots from
buds situated below the decayed portion. The attacked tissues
were completely rotted, and secondary infections by various bacteria
frequently occurred. The fungus was isolated from the diseased
tissues and formed sclerotia on various media. Out of the 68
Kaiserkrone tubers bearing Rhizoctonia scabs, the hyphae reached
the shoots in the manner described above in 39, and of the 196 shoots
borne by these 39 tubers, nearly 50 per cent. suffered from more or
less severe rot. The resulting plants were poorly developed and
their yield was reduced. The degree of infection was not lessened
by germinating the tubers in dry, damp, or sterilized sand.

Kartoffelkrebs. [Wart disease of Potatoes.|—Nachrichtenbl. fiir
deutsch. Pflanzenschutzdienst, 11, 10, p. 84, 1922.

The introduction of wart disease [Synchytrium endobioticum]
into the small holdings of Berlin and its suburbs has led to the
disease rapidly assuming the character of an epidemic, especially in
the case of the Wohltmann variety. The infection dates back at
least three years. At Dahlem a garden of about one acre in extent
is completely infested, while neighbouring properties, separated by
streets, appear to be still clean. The locality from which the infection
was introduced has not yet been ascertained.

Poote (R. F.). Recent investigations on the control of three
important field diseases of Sweet Potatoes.—New Jersey
Agric. Exper. Stat. Bull. 365, 39 pp., 10 figs., 1922.

The loss from stem-end rot or yellows, a disease which; can be
caused either by Fusarium batatatis or PF. hyperoxysporwm, may
amount to 65 per cent. or more in some parts of New Jersey, and 1s
increasing in virgin soils. The Yellow Jersey is the most susceptible
variety grown in the State, the Big Stem strains, the Red Jersey,
and the Gold Skin varieties being more resistant. The so-called
Southern Yams, such as the Porto Rico and Dooley varieties, are
highly resistant under New Jersey conditions.

The vegetative mycelia of the fungi penetrate the fibro-
vascular bundles of roots and stems, causing the wilting and death
of the foliage. Dissemination is effected largely by the use of
diseased seed-tubers and planting out infected cuttings, but soil,
wind, water, animals, and manures are also involved. The selection
of disease-free seed reduces the losses to some extent, even on
severely infected soils. Some infected plants are very productive,
yielding a large number of uniformly small tubers. Crop rotation
over several years has failed to control the disease. Comparative
trials with different fertilizers gave variable and inconclusive results
in regard to the incidence of infection. Careful management of

31

the seed-beds is very important. After a large leaf surface has
developed, sufficient water should be given to prevent the hardening
of the stems. Sprouts should be set in the field before the hardening
of the stems and general stunting takes place.

Ground rot, ‘pit’, or ‘pox’ (Cystospora butata) is severe in one
isolated area in New Jersey, infection ranging up to 85 per cent.
In other States this disease is also generally restricted to particular
areas. In the locality referred to the disease has spread only a few
miles in over thirty years. Soils that pack and harden after rains
are favourable to the development of the organism. Large and
small roots are attacked with equal severity. The growth of the
stems may be shortened as a result of the attack on the feeding
roots, the leaves lose their normal colour, and the yield is reduced.
The disease does not spread in storage or on sprouts. Sulphur
added to the soil at the rate of 200 to 400 lb. per acre is recom-
mended for the control of the disease, and also has the effect of
increasing the yield. The experiments in its use showed that
sulphur applied directly round the plants caused injury to the roots,
but that 300 to 400 lb. per acre of ‘inoculated’ sulphur [see this
Review, i, 3, p. 82] can be broadcasted with advantage on infected
soil about a month before planting. A higher proportion of nitrogen
is recommended for infected soils than is usually applied to sweet
potatoes.

Scurf or soil stain (Monilochaetes infuscans) causes an average
infection of 50 per cent. in New Jersey, and occurs even in virgin
soils. Severely infected potatoes may lose more than half their
weight in storage. The growth of the fungus is stimulated by
organic manures, especially when applied in the row. Spores are
formed best on a soil-extract medium. In storage the fungus
spreads from healthy to diseased potatoes. The disease was slightly
reduced by a combined application of lime and sulphur, while
sulphur, ‘inoculated’ sulphur, and ‘ Bac-sul’ were extremely effec-
tive. Inoculated sulphur applied at the same rate and time as in
the last disease is recommended. The destruction of the fungus on
the tubers may be effected by soaking the seed for eight to ten minutes
in 1 in 1,000 corrosive sublimate. The use of infected tubers for
seed should be avoided. Allowing a period of five years between
successive sweet potato crops gave a slight decrease in infection in
some cases, but in others no benefit was apparent.

SHAw (F. J. F.). A diseased condition of Rice.— Agric. Journ. of
India, xvii, 2, pp. 152-154, 1922.

The author states that a diseased condition of rice, similar to that
described in the United States under the name of ‘straighthead’ by
Tisdale and Jenkins [see this Review, i, 3, p. 83], is not uncommon
in India. He believes, however, that if the disease is due to lack
of soil aeration, as held by these authors, it is not improbable that
the deficit of oxygen is due to more complex causes than are
suggested by them. The presence of decaying organic matter in
the soil would at least suggest that bacterial activity may result
in the production of toxins, and that the benefits of aeration are
due rather to the oxidation of these toxins than to the direct supply
of oxygen to the plant. Besides, the fact that in some parts of

32

India large quantities of green leaf are puddled into the soil is in
contradiction to the view that decaying organic matter produces
a soil condition injurious to rice. Straighthead resembles ‘ brusone ’
in its two chief symptoms, namely the feeble development of the
fine root system and the lack of grain. Attention is called to the
work of Brizi, who showed that a diseased condition of rice with
root symptoms similar to those of ‘brusone’ is dependent on a
deficiency in the supply of oxygen to the roots. While this is not
considered to be sufficient to explain the occurrence of ‘brusone’,
the author considers that a more extensive knowledge of the bio-
chemical processes involved in the activity of the micro-organisms
of the soil would be of value in postulating a general cause for this
group of diseases.

Scientific Research Notes.— Bul/. Rubber Growers’ Assoc., iv, 3,
pp- 107-110, 1922.

The mycologists of the Malaya Research Branch of the Rubber
Growers’ Association report that A retzschmaria micropus, which
is commonly found associated with Ustulina zonata, may prove to
be a dangerous parasite.

Young rubber trees in South India are reported by Ashplant to
be affected by a die-back, caused not by Diplodia, but apparently
by Phytophthora meadii. The symptoms are confined to the
greener portions of the shoot, and the disease is arrested at the
nodes. It was noticeable that the attacks were chiefly on the side
of the plantation nearest to old rubber. It is suspected that the
fungus may live over the dry season in the tissues, as McRae has
shown to be the case with P. meadii, and the removal of all affected
shoots at a point three-quarters of an inch below the diseased zone
is recommended. Spraying may help to avert fresh outbreaks
during the next monsoon. The effects of the disease being most
serious on unbranched trees, leaf-pruning is advised as a means of
inducing the trees to branch.

Contrary to the general belief in the efficacy of the scraping and
tarring method in curing brown bast, a recent examination by
Ashplant of an estate so treated showed 98 per cent. of disease, in
spite of the unusual care with which the operation was conducted.
In 75 per cent. of the cases, however, the affection was so superficial
that a repetition of the treatment might eliminate it. The new
tissues were highly laticiferous, the quantity of latex derived sub-
sequent to scraping apparently equalling, if not exceeding, that
obtained prior to the outbreak of disease, although trial tappings
were not made.

Patch canker (Phytophthora) is far more prevalent in South
India than in Malaya or the Dutch East Indies, probably on account
of climatic conditions. Invasion of the cells by the patch canker
fungus leads to the formation of a protective corky tissue. Under
conditions favourable to the fungus (the excessive damp of the
early monsoon) all the tissues outside the corky layer are destroyed,
and in many cases the organism penetrates to the cambium,
causing an open wound. Later in the season the course of the
attack is modified by climatic changes, the dry, hot weather in-
hibiting the development of the fungus in the tissues. The chief

33

danger of patch canker is said to lie in the possibility of subsequent
physiological disturbances which may end in brown bast.

Dasu (J. S.). Insectes et maladies. [Insects and diseases. |—
Troisiéme Rapport Stat. Agron. Guadeloupe, 1920-1921,
pp. 14-16, 1922.

The previous season’s drought was responsible for a large exten-
sion in Guadeloupe of the root disease of sugar-cane due to Maras-
mius sacchari, especially in the coastal regions; in some cases the
erop of whole fields was almost destroyed. Sugar-cane mosaic does
not seem to occur in this island. Diseased cacao pods examined
at the station were found to be attacked by Phytophthora fabert;
practical measures for the control of the disease are recommended.
The only diseases of coco-nut palm observed during the year were
a few cases of bud rot and one of stem bleeding disease (’hielavi-
opsis paradox).

Overbrenging van Gelestrepenziekte door insecten. | Transmis-
sion of yellow stripe disease by insects.|—Abs. of a paper by
L. O. Kunkel in Hawaiian Planters’ Record, xxvi, p. 58, 1922.
Arch. Suikerind. Nederl.-Indie, xxx, 21, pp. 857-358, 1922.

The results of very careful experimental work in Hawaii showed
that Aphis sacchari, transferred from mosaic to healthy sugar-
canes, flourished and multiplied, but no infection was observed.
Experiments were also carried out with Aphis maydis (A. adusta),
specimens of which were transferred from diseased (mosaic) maize
‘plants to healthy Lahaina sugar-canes. In twelve days the first
symptoms began to appear, and by degrees most of the plants thus
treated became infected with mosaic, the controls remaining healthy.
This confirmed Brandes’s observations that A. maydis was an agent
in the transmission of yellow stripe or mosaic disease from maize
to sugar-cane.

Negative results have hitherto been obtained from similar ex-
periments with Peregrinus maydis (which is able, however, to
transmit the disease from one maize plant to another), and Perkins-
iella saccharicida. These investigations are still in progress.

The danger of direct transmission of the disease from cane to
cane by A. maydis appears to be slight. The insect only lives for
a few days on the sugar-cane, which cannot therefore take the
place of a permanent host like maize. Indirect infection by means
of other regular hosts of the insect, such as Hleusine indicu, Pani-
cum crus-galli, P. sanguinale, Polytrius diverisfloru, &e., is more

probable.

LEDEBOER (F.). Gelestrepenziekte. [Yellow stripe «lisease.|—
Arch. Suikerind. Nederl.-Indie, xxx, 21, pp. 359-362, 1922.

The author states that a full report of the experiments on the
transmission of yellow stripe (mosaic) disease of sugar-cane, carried
out at the Cheribon Sugar Experiment Station, is in preparation.
Meanwhile it is considered advisable to announce that Aphis
adusta has been proved to be an active agent in this transmission.
There is no actual evidence that A. sacchari is implicated, though
at one stage of the investigations this seemed probable. In the

34

course of the experiments it was ascertained that A. adusta occurs
much more generally in sugar-cane plantations than is usually
supposed, especially on Panicum colonum and Paspalum (Pani-
cum) sanguinale. These grasses, in which the virus of the disease
persists for long periods, are capable not only of infecting the canes
in their vicinity, but also serve as new sources of infection when
the diseased canes have been removed. All such grasses should
therefore be burnt or buried. The cultivation of susceptible varie-
ties of cane, e.g. the Cheribon-Chunnee crosses, should be restricted
to outlying districts, where they will not contaminate healthy
plantations.

VAN HARREVELD (P.). Gelestrepenziekte en bladluizen. | Yellow
stripe disease and green-flies. |—Arch. Suikerind. Nederl.-Indie,
xxx, 16, pp. 261-262, and 17, pp. 262-264, 1922.

It was recently announced in the Java Press by the Cheribon
Sugar Experiment Station that the yellow stripe (mosaic) disease
of sugar-cane was an infectious disease transmitted by the agency
of a green-fly, Aphis adusta (A. maydis). The exact cause of
yellow stripe disease, which in Java assumes the form of partial
chlorosis or mosaic, is still obscure, but this information will be of
great service to investigators. It has been proved by American
workers that the corresponding disease in Cuba, Porto Rico, and
Louisiana can be transmitted by green-flies, but it is not certain
whether the yellow stripe in Java is identical with the American
form of the disease.

Two species of Aphis occur on sugar-cane in Java, viz. Aphis
sacchari Zehntner and A. adusta Zehntner. The latter is much
less common than A. sacchari, and is frequently concealed between
the expanding leaves of the young shoots. It has not yet been
observed on sugar-cane in the gardens of the Java Sugar Industry
Experiment Station at Pasoeroean, although yellow stripe disease is
prevalent there. The suppression of A. adusta, which is common
on maize, sorghum, and other grasses, would be no easy task,
especially as it is so readily concealed. Other insects may also be
involved. In any case the method of selecting healthy canes from
the young setts is nct likely to be superseded by this new discovery.
Canes of the Chunnee variety have been known to suffer from
yellow stripe to the extent of 100 per cent. in the absence of any
contact with grass or green-flies. This susceptible variety does
not improve on being transferred to the mountains, but seems, on
the contrary, to deteriorate. Other varieties liable to the disease are
D152, 36, 213, 826, 979, 1499, 1507, 1547, and 2379 PO J.

Siccers (P. V.). Torula ligniperda (Willk.) Sacc.,a Hyphomycete
occurring in wood tissue.—Phytopath., xii, 6, pp. 369-373,
1 pl., 1922.

The examination of logs of white ash (Fraxinus americana)
from Tennessee and yellow poplar (Liriodendron tulipifera) from
Kentucky revealed the dark, catenulate spores of Torula ligniperda
scattered deeply in the wood. The fungus has been previously
recorded in spruce, fir, oak, Rhamnus cathartica, and Erica arborea
in Europe, and in maple, basswood, Tsuga canadensis, and red gum

39

in the United States. In the laboratory the author grew it in
cypress, white ash, yellow poplar, and cucumber tree.

The results of mechanical tests made on the yellow poplar and
white ash logs, and a careful comparison of the values obtained
with sound and infected test pieces, showed that in the former case
the differences in these results could scarcely be correlated with the
presence or absence of the fungus. In the white ash, on the other
hand, all the infected logs except one had a lower specific gravity
than the average tor sound logs, while the logs, in which infection
was readily apparent showed a marked decrease in strength values.

VRIEND (J.). Stachytarpheta vatbaar door slijmziekte. _{ Stachy-
turpheta susceptible to slime disease. ]|— Vlugsch. Deli-Proefstat.
te Medan [Sumatra], 16, 4 pp., 1 fig., 1922.

The occurrence of slime disease (caused by Bacillus solanacearum)
on Stachytarpheta indica in four different localities in Sumatra is
reported. The plant is found at times in tobacco fields, and seeds
freely in cultivated soils. The microscopic characters of the disease
corresponded to those of slime disease in tobacco; a bacillus agreeing
with B. solanacearum was found in the vessels, and an extract of
the diseased tissues caused the death of moculated tomato seedlings.
An extract from these produced typical slime disease in young
tobacco plants.

Stachytarpheta appears to be less susceptibie than tobacco,

‘possibly because of its more woody nature. There may be many
other similar hosts of B. solanacearum amongst the weeds of
tobacco fields, and if so they may have an important bearing on
the perpetuation of the disease.

Pato (B. T.). Verslag van het Deli Proefstation over 1 Juli
1920-30 Juni 1921. [Report of the Deli Experiment Station
from Ist July 1920 to 30th June 1921.]|—Meded. Deli Proefstat.
te Medan-Sumatra, Series I, 21, 72 pp., 4 figs., 1921 [1922].

The Botanical Department has been engaged in researches con-
nected with the selection of tobacco in which disease resistance is
taken into account. The question whether seed from plants affected
by mosaic or slime disease (Bacillus solanacearwm) inherits sus-
ceptibility to these diseases or not is also being studied. The
available evidence does not yet admit of a conclusive statement on
this subject, but it appears certain that the seed from mosaic plants
does not produce a greater number of diseased seedlings than that
derived from healthy plants. It has further been ascertained that
a number of common Solanaceous weeds on tobacco plantations are
also attacked by mosaic disease. Physalis and Solanum spp. are
frequently affected and undoubtedly constitute a source of infection
of tobacco. Mosaic also occurs on other plants, such as Passiflora
foetida, Jussiewa spp., Cucurbita spp., and various plants grown for
green manuring, but it is not yet certain whether it can be trans-
mitted to tobacco from plants belonging to other families.

Owing to the great difficulty of culturing the bacillus of slime
disease it was necessary to find some other method of establishing
its presence in the soil. Tomato seedlings, which are even more
susceptible to the disease than tobacco, and grow more rapidly, were

36

sown on tiles in about 1 em. of sterilized soil. When the seedlings
attained a height of about 5 cm. and developed four leaves they
were used for soil tests. An aqueous extract of the soil to be
examined was made (1 kg. of soil to 1 litre of water), and the
extract distributed as evenly as possible over the tomato seedlings.
The roots were then cut with a sterilized knife, the controls
being treated in exactly the same way, except that sterilized water
was substituted for soil-extract. If the soil was sufficiently rich in
B. solanacearum the symptoms of slime disease began to appear
in the infected plants after three or four days. After six days in
one test there was a total of twenty-seven infections from diseased
soil, as against an entire absence of contamination in the case of
‘healthy’ soil and the controls. It was found that weaker con-
centrations of the soil-extract (the extract as prepared above diluted
with one and with nine volumes of water respectively) resulted in
a reduction of infection. Thus, out of 108 plants, twenty-five were
infected after six days by the undiluted extract, while the lower
concentrations gave seventeen and eleven infections respectively.
This method has been very accurately worked out and should prove
extremely useful in determining the intensity of the soil con-
tamination.

Recent investigations, which are still incomplete, indicate that
infection commonly takes place at the moment of lifting the seed-
ling for transplanting. This explains the necessity of using only
seedlings from healthy beds. Other tests have shown that from.
ten to fifty per cent. of the cases of slime disease in the field are
attributable to the use of infected seedlings. Researches are also
in progress concerning the period of incubation of B. solanacearum,
and the breeding of a partially or totally immune strain of tobacco.

D’ANGREMOND (A.). Die Bekampfung von Phytophthora nicotianae
in den Vorstenlanden. [The control of Phytophthora wico-
tianae in the Vorstenland.|—Meded. Proefstat. voor Vorsten-
landsche Tabak, xiii. | Abs. in Zentralbl. fiir Agrikulturchemie,
li, 8, pp. 203-205, 1922.]

A number of samples of soil and manure have been analysed for
the presence of Phytophthora nicotianae by the following method.
The samples were stirred with water into a paste and spread on
living tobacco leaves, which were covered with a layer of banana
leaves. Twenty-four hours later the paste was washed off and the
leaves preserved in tins for some days, when the spots were
counted. The results showed that a large proportion of the stable
manure used in the Vorstenland province was infected by Phyto-
phthora. Comparative tests showed that the use of manure giving
a positive Phytophthora reaction, however slight, endangered the
tobacco crop. Even with a negative test the danger was by no
means absent. Control plots, on which stable manure was not used,
showed a much lower proportion of infection. Disinfection of the
manure with carbon disulphide was effectual, but too expensive.
The results of treatment with copper sulphate were not. satis-
factory. The use of stable manure for seed-beds is therefore very
undesirable. :

There are other secondary channels of infection, such as the water

37

flowing from old tobacco fields to new ones, the floors of store-
houses, &c. The practice of planting out seedlings between the
existing rows of tobacco plants should also be avoided.

VauLeAu (W. D.) & Kinney (E. J.). Strains of Standup White
Burley Tobacco resistant to root rot.— Kentucky Agric. Exper.
Stat. Circ. 28, 16 pp., 6 figs., 1922.

Root rot (Thielavia basicola) causes very serious losses to Ken-
tucky tobacco growers, and pure line selection work has therefore
been undertaken with a view to developing resistant strains.
Twenty-five resistant strains of Judy’s Pride and Vimont Kelley
White Burley Tobacco have now been tested, and about fifty other
selections have been made from a Standup variety called Station
Kelley. The results so far secured indicate that it is possible to
obtain strains of White Burley which combine high quality with
immunity from root rot.

Ciinton (G. P.) & McCormick (FLORENCE A.). Wildfire of Tobacco
in Connecticut.—Connecticut Agric. Exper. Stat. Bull, 239,
pp. 865-423, 4 pl., 1922.

Tobacco wildfire (Bucteriwm tabacum) difters from all other leaf
spot diseases in certain definite characters. Both in the seed-bed
and the field, infected plants develop yellow discolorations in the
green tissues, the spots usually being rounded and about the size of
a finger tip. In the centre of the spots is a small point of white to
brownish, dead tissue, which gradually encroaches on the yellow dis-
coloration. The latter then becomes limited to a narrow, encircling
band, or halo. In severe cases a large part of the leaf surface may
be killed, and damage up to 60 or 70 per cent. has been estimated
to occur in a number of fields. The symptoms of the disease in
advanced stages resemble sun scorch or the so-called rust following
calico. The yellow halo rings, however, generally persist to the
end.

An examination of specimens of tobacco from Rustenburg, South
Africa, convinced the writers, in spite of the recently published
statement to the contrary [see this Review, i, 11, p. 376], that the
disease in that country was identical with wildfire in the United
States. Inoculation experiments with a water extract of crushed
infected tissues sent from South Africa in January 1922 proved
unusually successful. It is suggested that a more careful com-
parison of angular spot and wildfire is required. In the United
States wildfire has been reported from North Carolina, Virginia,
Maryland, Massachusetts, Kentucky, Tennessee, Wisconsin, Georgia,
Pennsylvania, Vermont, Florida, and possibly South Carolina. It
was first recognized in Connecticut in 1919, and was probably
introduced with seed, though possibly in matting, fertilizers, or
other imports from some infected area.

Previous workers have held that the disease is seed-borne, but
the writers’ own experience does not suggest that the seed is the
chief source of annual infection in Connecticut. There seems to be
no doubt that the seed-pods are liable to infection under favourable
conditions, while healthy seed may also be contaminated by dust
laden with germs. One of the most frequent methods of spreading

38

the disease is the planting of seedlings from infected fields. Other
probable agents of dissemination are implements, the old tent-cloth
used for seed-bed coverings, insects (especially flea-beetles), wind
and rain, and the workers passing from one tield to another.

It is not known how long the germs of the disease can remain
attached to the dry seed and retain their viability, but it is assumed
that the organism may overwinter on one-year-old seed so as to
reinfect the next year’s seedlings. It is very unlikely that the
germs retain their viability as long as the tobacco seed, which
germinates fairly well when eight to ten years old. Possibly the
germs may overwinter in old canvas, in the soil, or in tobacco
refuse.

In May 1921 the senior writer examined some seedlings which
showed symptoms of rotting and shrivelling at the tips or upper
edges of the leaves. Under favourable moisture conditions the
plants ultimately shrivelled up altogether, leaving vacant patches
in the beds. In less severe cases the rotten tissues fell away,
leaving the rest of the leaf apparently healthy. Masses of bacteria
were found in certain intercellular spaces in the rotten tissues. The
general appearance of the seedlings resembled that of plants attacked
by the damping-off fungi. About a week later these and other
plants at a somewhat more advanced phase of growth showed the
typical halo spots described above. The wet rot was evidently the
first stage of the wildfire disease, not hitherto described. Probably
the first leaves of very young plants come into contact with the soil,
whence the wildfire germs may penetrate into the intercellular
spaces through the large stomata at the tip or margin of the leaf.
The second stage of the disease is the halo or yellow spot referred
to above, and the third stage, which does not usually occur until
the seedlings have been transplanted into the field, is the death of
the healthy tissues between the spots. Plants left in the infected
seed-beds are apparently not subject to a progressive form of the
disease, partly on account of the reduction in moisture accompanying
the removal of the covers, and partly because of the slow growth of
the thickly set plants, which checks the spread of infection.

Cold, wet weather favours the development of the disease, which
is always particularly serious when rain-water stands on the leaves.
For this reason glass is a better protection to the seed-beds than
cloth, and it also facilitates airmg the beds. The latter should be
lightly watered, preferably in the early morning or late afternoon.
The Broadleaf, Havana, Cuban, and Round Tip varieties are all
susceptible, especially the two former. As all Connecticut tobaeco
is‘grown for wrappers, the leaf injury results in much greater loss
than in localities where the leaves are used for other purposes.

Southern investigators lay great stress on seed treatment for the
control of the disease, but the writers question the importance of
this measure in the north. Experiments in Connecticut with
formalin (1 oz. to 1 pint of water for 15 minutes), and corrosive
sublimate (1 part to 1,000 of water for 15 minutes), recommended
by Fromme [see this Review, i, 3, p. 94], have resulted in the death
of some of the seed, especially with formalin. Where the seed is
suspected to have come from a diseased crop, disinfection with
corrosive sublimate should be carried out. Steam sterilization of

=

Ss

~ 4 | >-

39

infected soil at a pressure of 100 lb. for 30 minutes before the next
year’s planting is recommended. Spraying the seedlings with
Bordeaux mixture, 4-4-50, and lead arsenate, has given excellent
results and was not found to injure the plants appreciably. The’
first application should be given when the seedlings have just taken
root, the largest leaves then being about the size of a thumb-nail,
and the spraying should be continued every week thereafter until
the end of the transplanting season. The writers believe this to be
the only remedy which prevents the spread of wildfire in a bed, no
matter what the source of its introduction. For the field crop the
removal of infected leaves once or twice shortly after the plants
have started to grow may somewhat reduce infection, and in some
cases, if the infected plants are still small, ploughing up and
resetting with new seedlings may be recommended. Such cases
must be left to the discretion of individual growers. The greatest
care should be taken to transplant out only plants absolutely free
from the disease; if this is done, the grower has usually little to
fear in regard to the field crop. After pulling the plants for trans-
planting, infection may spread from diseased to sound plants,
especially if left wet in baskets overnight before planting out.
Aerial spread from a distance into isolated fields planted with
healthy seedlings does not appear to be common. Spraying the
field crop is not believed to be practicable on account of the cost
and the unknown effect of the spray on the quality of the mature
leaf. Nitrogenous fertilizers promote rapid, watery growth and
thus indirectly favour the development of the disease. Potash has
been recommended as tending to increase resistance by promoting
a hardier growth.

Cultures of Bacteriwm tabacum are fairly easily obtained from
the wildfire spots on tobacco leaves, the organism being isolated
with equal facility either from the dead centre or the yellow halo.
There are certain discrepancies between the characters attributed
to the organism by Wolf and Foster (Jowrn. Agric. Res., xii,
pp. 449-458, 1918) and those observed by the present writers. The
former give the dimensions as 2-4 to 5 by 0-9 to 1-5 y, the latter
as 1-3 to 2-5 by 0-6 to 0-8 ». The writers also found one to four
or even five flagella, Wolf and Foster only one. The dimensions of
Bacterium angulatum, the cause of angular leaf spot, are stated to
be 2 to 2-5 by 0-5 y, the number of flagella ranging from three to
six. These particulars do not differ widely from those of B. tabacum
as observed by the present writers, and may account for the preva-
lent confusion between the two diseases.

By puncturing the tissues infections were easily secured in the
leaf parenchyma, ribs, or stems of growing greenhouse plants,
especially young plants. In general, young, recently isolated
cultures were more virulent than those several months old that
had been frequently subcultured. In nature, however, infection
undoubtedly takes place as a rule through the open stomata. The
writers have not observed the occurrence of wildfire on any weeds
or plants in or near tobacco fields, and their inoculations on tomato
and other related plants were also unsuccessful. It is stated,
however, that Chapman and Anderson (Mass. Agric. Exper. Stat.
Bull. 203, p. 74, 1921) inoculated petunia, eggplant, and pokeweed

40

(Phytolacca decandra) by spraying with suspensions of the bacteria
in water, and also isolated the wildfire organism from spots on
tomatoes growing in an infected tobacco seed-bed. The organism
can remain alive in dried leaves for about a year, but not much
longer. It can live in the soil for short periods, and there are
indications that it overwinters in soil at times.

A full bibliography of thirty-four titles is appended.

GARDNER (M. W.) & Kenprick (J. B.). Overwintering of Tomato
mosaic.— Botan. Gaz., |xxiii, 6, pp. 469-485, 1 pl., 1922.

Tomato mosaic might conceivably be carried over winter in
Indiana by means of hot-house tomato crops, in tomato seed, in
related perennial weed hosts, or by insects. Hot-house tomatoes
do bear mosaic during the winter, but are not widely grown, and
will not account for the widespread appearance of mosaic in the
tomato crop in the fields. In a total of 22,944 tomato plants
grown from seed from mosaic plants, no evidence of seed transmis-
sion of the disease was obtained. Previous workers have not found
that aphids carry it through the winter.

Perennial weeds were found to be important agents in the over-
wintering of the disease. It has been found in the weeds Physalis
subglabrata, P. virginiana, P. heterophylla, and Solanum caroli-
nense, and has been transmitted from each of these to the tomato.
P. subglabrata carries mosaic over winter in its rootstocks, and the
symptoms appear on the young shoots in the spring. This weed is
very prevalent in Indiana. Mosaic does not commonly occur spon-
taneously in Piiysalis weeds, but infection was common when these
weeds grew in fields which had grown tomatoes, and was found to
have spread to them over a distance of 200 to 400 ft. from the
tomatoes. Aphids, and apparently also flea-beetles (Hpitria cucu-
meris), may serve to distribute the mosaic.

Mosaic has been transmitted from tomato to the annual plants
Solanum vigrum, S. integrifolium, and Lycopersicum pimpinnelli-
folium, but.not to Datura stramoniwm. It has also been trans-
ferred from tobacco to tomato, and has been noted on cultivated:
Physalis pubescens. Susceptible annual weeds may aid in the
spread of the disease during the growing season.

Solanaceous weeds, especially the perennial ones and those in
and near tomato-plant beds early in the season, should be eradicated
as a control measure against mosaic.

PritcHARD (F. J.). Development of wilt-resistant Tomatoes.—
U.S. Dept. of Agric. Bull. 1015, 18 pp., 10 pl., 1922.

Tomato wilt (Fusariwm lycopersici) causes an estimated annual
loss of over 115,000 tons of tomatoes in the Middle Atlantic, Gulf,
and lower Mississippi Valley States, and is also prevalent in the
Ohio River Valley, California, and parts of Colorado and Utah.
The only reliable means of controlling wilt (the symptoms and
effects of which are briefly described) is the development of
resistant varieties.

From 1915 to 1919 the writer was engaged in an attempt to
breed resistant strains. The original selections were made from
the worst wilt-infested fields that could be found, and pure line

41

selections from these were tested by repeated plantings on infected
soil. The resistance of the strains was graded by a combination
of characters correlated with the degree of infection, namely, the
percentage of infected plants, the percentage of dead plants, and
the yield of fruit.

The only commercial varieties combining natural resistance with
size and quality of fruit were found to be Duke of York and
Buckeye State, which the author regards as virtually identical.
Livingston’s Globe was somewhat resistant, but besides being very
susceptible to nail-head rust (Macrosporiwm sp.), it is unsuitable for
canning. Absolute immunity was not exhibited by any of the
forty varieties tested during the period under review. In the 1915
test the Louisiana Wilt-Resistant showed the smallest percentage
of plants killed by wilt and Willis the highest, but in subsequent
years Duke of York and Buckeye State gave almost as good results
as Louisiana. In 1918 The Marvel, Columbia, Norton, Arlington
(these four being strains developed by the writer from the Greater
Baltimore, Stone, and Merveille des Marchés varieties), Louisiana
Red, Louisiana Pink, and Tennessee A 16-2 were almost free from
wilt, while John Baer, Greater Baltimore, Stone, Royal Red, Dela-
ware Beauty, Red Head, Early Jewel, and Bonny Best were almost
destroyed by the disease. The Mansfield tree tomato was fairly
resistant, but produced little fruit; the results of tests with the
Success and Mississippi Girl varieties were conflicting.

Most varieties differ little in the wilt resistance of the individual
plants within the variety. A few, however, showed great variability
in this respect, and selections can be made from them that transmit
a high degree of resistance. Most selected plants transmit to their
offspring approximately the same degree of resistance possessed by
the parent plant, though occasionally the character may be strength-
ened in the second selection. The process of selection is somewhat
complicated by environmental factors, which cause a certain amount
of fluctuation in the character of resistance. On an average, how-
ever, wilt resistance is less variable than tomato fruit characters,
its stability being maintained under both continued and discon-
tinued selection, and in a number of different localities.

Several very resistant strains have now been developed by the
writer, and are of high yield and superior quality of fruit. Field
tests have been carried out with them in various parts of the
United States, and have given excellent results. These strains are
deseribed in detail.

CHAMPION (H. G.). Notes on the death of Chir (Pinus longifolia)
poles in the Almora plantations of Kumaon.—Jiulian
Forester, xlviii, 4, pp. 168-174, and 5, pp. 232-246, 1922.

Since 1916 the author has carried on investigations and collected
all the available information regarding the extensive mortality in
young Pinus longifolia grown from seed sown since 1875 in the
Almora plantations, in the Himalaya. The disease was observed
by Stebbing in 1908, and ascribed to the attacks of a weevil. This
view is critically examined by the writer, who is satisfied that the
insect is secondary to the real cause of the trouble. The same
applies to the other insect pests found by the writer, full notes on

42

which are given. The deaths occur principally among trees of 13
to 4 ft. in height, especially on dry and shallow soils, but in certain
districts well-established poles of thirteen years old and 1 to 2 ft.
in girth, growing in good soil, have succumbed on a large scale.
Schistose rock is the foundation of most of these soils, and there is
an abundance of grass, much of which is Andropogon repens. In
one district the loss of plants under 1 ft. in girth amounted in
1918-19 to 2,055 and in 1920-21 to 930. In the course of three
years a sample plot of trees, 14 to 2 ft. in girth, has lost 25 per cent.
of its dominant trees.

Three years is the normal period elapsing between the first
symptoms and death. During this time the appearance of the
crown remains quite normal, though removal of the bark may
show that the cambium has been completely girdled for at least
twelve months. The growth in height, the length and density of
the needles, and the date of expansion of the buds are not affected
by the disease. At length an abrupt change takes place. The
twigs lose their normal brittleness and the foliage its bright
colouring, and in a week or two the entire crown turns yellow and
dry. There is usually a more or less copious exudation of resin
from the basal parts of the stem, generally extending over a zone
from 4 to 34 ft. in height. In all cases death seems to be the final
result of the resin flow, though one tree has survived since 1918.
The cases are frequently, but by no means always, concentrated
in patches. The advanced stage of the disease may be observed
at almost any time of year, but the periods of maximum incidence
are March to April, coinciding with the renewal of growth after
the winter rest, and August, corresponding to the height of insect
activity.

The primary cause of the disease is believed to be the fungus
described by Barclay as Peridermium complanatum var. corticola.
The writer, however, thinks that the fructifications on the needles
are not due to the same fungus as those on the bark, their identity
never having been demonstrated. They are here referred to, for con-
venience, as ft. acicola and f. corticola. The former is extremely com-
mon, but appears to do little damage to its host. The bark form is
less common in natural regenerations, but in the plantations may
become severe. It sends its orange aecidia through crevices of the
bark towards the end of the hot weather in May. External bleeding
is not always caused, but a trickle of resin may be the first indiea-
tion of an infection. An examination of the cortical tissues below
the origin of such a flow revealed on one occasion a mycelium
probably belonging to the Peridermium. Reduced resistance and
the resin flux attract various injurious insects, which complete the
destruction of the tree.

The general indications show that the fungus is prevalent enough
to account for the damage. In a plot 100 ft. square, in one planta-
tion, 77 out of 127 plants, 2 to 6 ft. in height, showed the fructifi-
cations of the corticola form, while f. acicola was present on all the
trees. The fructifications of the former generally occur on the
main trunk, 6 in. to 3 ft. from the ground, and are often confined
to one side. T'wo cases were noted in which one or two branches
became badly infested, swollen, and cankered ; they finally dried

43

off without infecting the rest of the tree. In no case so far seen
could the swellings and cankers sometimes found be attributed
exclusively to the action of the fungus. Possible alternative hosts
mentioned are Crataegus and Rosa moschata.

Drastic measures are necessary for the control of the disease.
All trees showing signs of going off colour should be immediately
removed and burnt, taking care to cut a few inches below ground-
level. It is of the utmost importance to eradicate infected plants
before the spores are shed. Any new sowings on a large scale
should be made in uninfected areas. The plantations near Almora
are isolated from other pine forests, so that the danger of external
infection is small. Frequent inspections are essential, especially in
April and May, the only months when the fungus is sure to be
visible.

Fars (H.)& Tonpvz(P.). Rapport annuel 1921. Station fedérale
d’essais viticoles 4 Lausanne et Domaine de Pully. {Annual
Report for 1921 of the Federal Station of Viticultural Experi-
ments at Lausanne and the Domain of Pully.]|—Reprinted from
the Annuaire agricole de la Suisse 19.22, 20 pp., 7 figs., 1922.

The Cantonal Viticultural Station at Lausanne (Vaud) was in
1920 transformed into a Federal Station serving the cantons of
Fribourg, Geneva, Neuchatel, Ticino, Valais, and Vaud. The
Station has as its objects the perfecting of the various methods
of control used against the insect and fungous parasites of the vine:
the prevention or cure of ‘ diseases’ of wines, and the development
of viticulture in the canton of Ticino, where a series of researches
has been undertaken in collaboration with the Agricultural College
of Mezzana. In addition to this work the Station is also carrying
out a series of investigations in fruit growing. It is proposed to
undertake the selection of the most suitable varieties of apple for
dessert and cider-making respectively, in order to increase the
desirable types and eliminate the inferior ones already in cultiva-
tion. Special attention will be given to different blends of varieties
suitable for cider-making, and also to problems of cultivation,
manuring, and the control of parasites.

The section of physiology and pathology deals, among other
subjects, with diseases of the vine, fruit trees, and other plants, and
the comparative efficiency of the various fungicides, &c., utilized in
phytopathology, while that of viticultural chemistry and fermenta-
tion is concerned with the study of ‘diseases’ of wine and cider,
the control of proprietary insecticides and fungicides, the selection
of pure races of yeasts, and the general microbiology of viticulture
and agriculture, in addition to more purely chemical problems.

A short account is given of the activities of the Station during
the year. The results of the two chief inquiries of interest here
have been separately published, and are noticed below.

Fares (H.), Tonpuz (P.), & STaAEHELIN (M.). Iba lutte contre le
mildiou en 1921. [The campaign against mildew in 1921.]—
Stat. féd. Vessais vitic. de Lausdnne, Pamphlet, 14 pp. [1922].

It would appear, generally speaking, that meteorological con-
ditions during the last few years have been more favourable for

44

the control of [downy] mildew [Plasmopara viticola] than was the
case during the period 1901-1917. In 1921 the writers carried out
a series of observations in the vineyard of Pully, which is connected
with the Federal Station of Viticultural Experiments at Lausanne.
The incubation period of the fungus during the summer varied
from seven to eleven days. The principal phases in the develop-
ment of the disease are described, and a chart is given showing
the variations in temperature and other meteorological conditions
from May to the beginning of October. The season was very
favourable to the development of the vine, and the damage caused
by the fungus was therefore inconsiderable, except in the case of
a few plots treated with inferior fungicides.

Attention is drawn to the difficulties encountered by the meteoro-
logical experts ‘attached to the viticultural stations in warning
growers of the necessity for treating vines. The system of fore-
casting attacks is based on the incubation period of the fungus,
and, as the season advances, the successive invasions overlap and it
becomes necessary to provide not only for the treatment of each
fresh wave, but also for that of previous infections. Attempts to
do this every time that the meteorological conditions are favourable
for sporulation and infection usually lead to too many applications
of fungicides being recommended.

Experiments were carried out with eleven preparations for the
control of mildew, two of which, the Bouillie Villedieu and ‘ Burdigal’,
contained no copper. These two proved complete failures and need
not be further considered. The results with the others are sum-
marized below :—

Bouillie mixte (a commercial preparation containing sulphates
of copper, nickel, zinc, and iron), 3 kg. of the mixed sulphates,
neutralized with the corresponding quantity of milk of lime, per
hectol. of water. The preparation was very effective, scarcely a trace
of the disease being observed. The leaves fell in October. Kurtakol
(a commercial preparation of colloidal copper), 500 gm. to 1001.
of water. Slight attacks of the fungus occurred, but the foliage
remained in good condition till November. This preparation is
worthy of extended trials. Neutral verdet [copper acetate],
1,000 gm., gelatine 500 gm., water 1001. The attacks were very
shght and the foliage well preserved. The adhesiveness of the
mixture was very marked. Caffaro paste (a commercial preparation
of oxychloride of copper), 1 kg. to 1001. of water. The treatment
was not begun till June, and the results were not altogether success-
ful, several slight attacks occurring and the foliage turning yellow
in the middle of September. Bordeaux mixture (3 per cent. copper
sulphate) and casein (50 gm. per hectol.). This treatment was most
effective, infection being reduced to a minimum. The copper
adhered to the leaves unusually well, forming a coating which
completely resisted the action of rain; it is not necessary to add
more casein than the quantity given above. Bouillie Sanavigne
(a commercial cupric mixture with casein), 1,000 gm. to 100 1. of
water. Excellent results were obtained, mildew being almost
absent. Sulfadhérent (a commercial preparation of lime and casein
to be added to copper sulphate solution made by dissolving 3 kg.
CuSO, in 1001. water). The vines were well protected against

45

mildew, but in spite of the great quantity of caseined lime employed
the adhesiveness of the preparation was no greater than in the
ordinary caseined Bordeaux mixture. The consistency of the mix-
ture is too thick and the spraying machines become clogged.
Kukaka (a commercial caseined cupric mixture prepared in Ziirich).
Moderate protection against mildew. Insufficient resistance to the
action of rain. Ordinary Bordeaux mixture (3 per cent. copper
sulphate). Results satisfactory on the whole.

lt is pointed out that the critical period in the development of
the disease in the area referred to is from the end of May to the
end of July. If during this period the oily patches of infection
appear seven to ten days after a warm rain, vigorous measures
should be taken to protect the sound foliage from infection.

Fars (H.) & STAEHELIN (M.). Le coitre de la vigne (Coniothyrium
diplodiella) ou maladie de la gréle. |The coitre (Coniothyrium
diplodiella) or hail disease of the Vine.]—Stat. féd. d’essais
vitic. de Lausanne, Pamphlet, 14 pp., 7 figs. [1922].

Coitre, livid rot, or hail disease of the vine is caused by Conio-
thyrium diplodiella Sacc., a fungus that has certain analogies with
the black rot organism (Guignardia bidwelliz) with which it is often
confused. A brief account is given of the history and distribution of
the parasite, which has been recorded from Italy, France, Austria,
Hungary, America, Algeria, and Switzerland. The most compre-
hensive work on the disease is that of de Istvanffi (Etudes sur le rot
livide de la vigne (Coniothyrium diplodiella), Ann. de U Inst. central
ampélologique royul hongrois, ii, 1902). The present article is
intended only as a preliminary outline of the problems. still
demanding investigation, the most important of which are stated
to be the following :—

In the vineyards*of Latin Switzerland epidemics of livid rot
generally occur only after a hailstorm, whereas in other countries
they often take place independently of the latter. The reason
for this is not yet clearly known, and requires investigation based
on exact knowledge of the local conditions of climate and cultiva-
tion in the different areas affected. Even in Latin Switzerland
every hailstorm is not necessarily followed by an outbreak of livid
rot. It sometimes happens that hailstorms in July and August,
months ordinarily favourable to the disease, do not bring on an
attack, and the reason for this is, again, unknown. Furthermore,
little is known as regards the treatment of livid rot. The practice
of cutting the grape-stalk above the point of attack in order to
prevent the spread of the fungus is lengthy and tedious, and can
only be carried out over a limited area. Treatment with copper
sulphate mixtures immediately after hailstorms does not appear to
have much effect on the disease, but is usually recommended in the
absence of anything better. The application of sulphur immediately
before or after a hailstorm has also been advised, but without any
scientific justification. All that is known is that the spores of
Coniothyrium diplodiella are highly resistant to the action of
copper salts.

The authors’ own observations indicate that infection of the

46

grapes occurs through wounds inflicted by hail. The spores actually
penetrate through these wounds and germinate in the interior of
the grape. The mycelium ramifies quickly through the tissues
of the fruit, extends down to the rachis, and from the latter reaches
other grapes of the bunch. The damage is most severe on mature
grapes, especially at the end of July and during August, owing to
the high sugar-content of the fruit at that time. The fungus may
begin its attack at any point on the bunch, never attacking all the
grapes simultaneously. The first symptom of infection is the
appearance of zones of different colours on the grape. The outer-
most zone is of a greenish-golden colour, and this is followed by
a reddish-yellow and a brownish zone, the centre of the spot being
livid in colour. Gradually the entire grape assumes the livid hue
and becomes dotted with pyenidia varying in colour from greyish-
white to rose-brown. At this stage the rot is a ‘wet’ one, and the
grapes adhere loosely to the pedicels and are easily detached by
the wind or any slight shock. Those that remain gradually become
mummified, adhering very firmly to the stalk in this state and
giving rise in the following year to new spores which perpetuate
the disease. De Istvanffi estimates the average number of pycnidia
on an ordinary-sized grape at 200, each containing about 80,000
spores, which retain their viability for nine or ten months under
dry conditions. When the pycnidia are placed in a drop of water,
the whole mass of spores exudes through the ostiole. Those given
out by young pyenidia are mostly hyaline, those from the older
pyenidia coloured; both kinds germinate readily in nutrient solu-
tions, giving rise to a hyaline, septate mycelium with granular
contents and numerous vacuoles.

Inoculations were carried out at Pully on the 5th August 1921
with spores from mummies of the previous year, kept dry in the
laboratory until forty-eight hours before use, when they were placed
in a warm, damp situation. Drops of water containing these spores
were placed on Chasselas grapes which had been wounded with
a scalpel. On 8th August the infected grapes showed the typical
livid discoloration and the pedicels were turning brown and shrivel-
ling. The next day the infection spread from the pedicels to the
unwounded grapes. The pycnidia appeared on the surface two days
later, and by the end of the month the infected bunches were almost
entirely mummified. On the control bunches, which were wounded
but not inoculated, there were slight evidences of Botrytis cinerea,
but no livid rot. These results prove that livid rot is not caused
by wounding alone, as, for instance, by hailstones, but the spores of
the fungus must also be present, which was evidently not the case
on the non-inoculated grapes'in this vineyard. Further inoculation
experiments were undertaken to ascertain whether infection could
be produced through wounds on the leaves, peduncles, and shoots.
The results were all negative so long as water was used to germinate
the spores, thus agreeing with the practical experience of the local
vine-growers, who have never observed livid rot elsewhere than on
the grapes. It was noticed that the spores germinated much more
readily in grape juice than in water, this fact being, no doubt, one
of the reasons why wounds favour infection. Further attempts to
inoculate leaves with spores sown in drops of grape juice were

47

successful, entry into the leaves probably occurring through the
stomata. The minimum amount of sugar required for spore-
germination was found to be about 0-01 per cent. With a nutrient
solution containing 2 per cent. of sugar, germination was rapid and
complete, but there was none when the sugar-content was only
0-001 per cent. ee.

Experiments on the treatment of the disease are still in the
preliminary stage. Applications, two hours after infection, of Bor-
deaux mixture (3 and 4 per cent. copper sulphate) and of potassium
bisulphite (2-5 per cent.) gave promising results. A lapse of four
days between artificial infection and treatment rendered the latter
completely useless.

Der Referentenentwurf des neuen Pflanzenschutzgesetzes. [ Ex-
tract from the new Plant Protection Order.|—Deutsche Obst-
bauzeit., xviii, 32, pp. 299-300, 1922.

The following is a summary of the new order regulating measures
for the suppression of diseases and pests injurious to cultivated
plants in Germany.

The Plant Protection Service is carried on by (a) the Biological
Institute for Agriculture and Forestry at Dahlem, Berlin; and
(b) local head-quarters of the Plant Protection Service in the various
districts of the country. The establishment and maintenance of
these local head-quarters and the organization and development
of the Plant Protection Service in the different provinces is in the
hands of the provincial authorities, but is carried out in accordance
with regulations issued by the Minister of Agriculture and Food
Supply. The authorities of the different provinces may unite for
the execution of the order.

The diseases and pests to be dealt with, together with the means
of control, will be announced by the Minister of Agriculture. The
directions for treatment will be issued by the authorities in con-
sultation with the experts of the Plant Protection Service.

On the occurrence or suspected occurrence of any such disease or
pest, the occupier [‘ Besitzer’] of the infected land is to notify the
proper authority within three days. The local head-quarters of the
Plant Protection Service, on discovering the existence of a notifiable
disease or pest, must provide for the immediate execution of the
prescribed directions. In urgent cases they may issue special direc-
tions for control, immediately informing the Biological Institute
that they have done so. In cases where the occupier does not agree
with the findings of the local Plant Protection authorities, the
verdict of the Biological Institute must be obtained and is final.

The occupier of the ground on which the disease or pest occurs is
obliged to carry out, at his own expense, the directions issued by
the local head-quarters, and to give every facility for supervision of
the work by the proper authorities. He has the right to appeal
against the directions, but the work is not to be suspended pending
the hearing of the appeal.

In the event of the occupier refusing to carry out, or carrying
out inadequately, the prescribed measures, the local head-quarters

43

may carry them out at his expense. He is not entitled to compensa-
tion for loss or damage resulting from the prescribed measures.

Duly authorized members of the inspection staff are entitled to
enter private land, buildings, &c., and to remove samples.

The import of plants and parts of plants into Germany is already
partly regulated by Orders issued on 16th January 1917 and
22nd March 1920. These Orders are not affected by the new Order,
which further extends them.

The import into German territory of plants and parts of plants
regarded as carrying dangerous plant diseases or pests, and the
import of injurious pests and germs of disease is prohibited. The
Minister of Agriculture shall determine what plant diseases, pests,
and germs are to be regarded as dangerous, and also what plants
and parts thereof are to be regarded as bearers of them. Importation
of living plants and parts of plants is restricted to certain points of
entry and requires an import-permit. The latter will be issued,
subject to inspection of the consignment on arrival, in the fol-
lowing cases:—(a@) consignments from countries with adequate
plant protection legislation when the consignment is accompanied
by a certificate of examination, signed by an official expert, and
stating (1) that the contents of the consignment are free from
diseases and pests which would exclude it from admission; and
(2) that the consignment originated in a locality free from infection.
(b) Consignments from countries with inadequate plant protection
legislation in accordance with directions to be issued by the Minister
of Agriculture and Food Supply. [The remainder of the Order
deals mainly with the penalties attaching to infringements of the
various sections. |

Décret du 21 décembre 1921, No. 15198, approuvant le régle-
ment de la défense sanitaire végétale au Brésil. [Decree of
21st December, 1921, No. 15198, authorizing the regulation of
sanitary measures for plant protection in Brazil.|—Diario
official, No. 14, 18th Jan., 1922. [Abs. in Bull. mens. des Ren-
seignements agricoles et des Maladies des Plantes, xiii, 5-6,
p. 809, 1922.]

The decree prohibits the importation, commerce, and transit in
Brazil of live plants or parts of plants attacked by diseases or
parasites recognized as dangerous; of harmful live insects at all
stages of their development; of cultures of bacteria and fungi
injurious to plants; of soils and organic débris liable to contain, at
whatever stage of development, cryptogamic, or insect, or other
pests of plants, even if such material forms an integral part of
living plants; and of boxes, sacks, or other packing-material having
served for the transport of the above-mentioned products.

The Minister of Agriculture, Industry, and Commerce is further
authorized to prohibit the importation of any vegetable product
originating in countries where diseases and pests, the introduction
of which would constitute .a menace to home-grown crops, are
prevalent.

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

APPLIED MYCOLOGY

Vou., If FEBRUARY 1923

Brown (J.G.). An undescribed fungus on the Pepper tree.— Abs.
in Sczence, N.S. lv, p. 547, 1922.

The pepper. tree (Schinus molle), which is grown as an ornamental
tree in warmer areas in the south-western United States, was found
attacked by a fungus causing rotting of the wood. The branches
may die gradually, or the entire tree may wilt and die suddenly on
account of mycelial growth in the tracheae. Infection takes place
through wounds.

Sporophores were found on the trunk and branches during the
rainy season, and are bracket-like, brown to blackish, azonate,
annual, usually from 12 to 15 cm. in diameter. The fungus is
named Jnonotus schini n. sp.

DurrEnoy (J.). The occurrence of Cronartium ribicola in Europe.
—Phytopath., xii, 6, pp. 802-304, 1922.

In Europe the aecidial stage of Cronartiwm ribicola chiefly oceurs
on the Weymouth pine (Pinus strobus), though P. lambertiana and
P. flewilis may also be infected. The disease has not been observed
in southern or central France. The teleuto stage is uncommon,
and has never been seen by the author on wild Ribes. References
are given to the published records of the distribution of this fungus
in some other European countries.

MaAcCatLum (Betta D.). Some wood-staining fungi.—TZ rans.
Brit. Mycol. Soc., vii, 4, pp. 231-236, 2 pl., 1922.

After a short reference to the literature on wood-staining fungi,
the author states that ‘blue-rot’ has been known for many years
in Great Britain, and it has been assumed to be caused by one or
more species of Ceratostomella, without, so far as she knows, any
description of the species concerned. Her present investigation
showed that C. pini Miinch and C. piceae Minch occur very com-
monly in and around Edinburgh, and in all the woods visited
between that town and Inverness. In all the cases affecting standing

B

50

trees which have come under observation the bark of the tree was
riddled with holes made by the pine beetle Hylesinus piniperda.

The author gives a detailed account, based on the study of arti-
ficial cultures, of the life-history of C. piceae. This species occurs
as a nearly pure growth on Picea excelsa. It is not certain how
far it stains the wood. In Scotland spruce timber is quite unstained
by it even when perithecia occur thickly all over the surface. It
occurs very frequently on badly stained Pinus sylvestris, but has
never been found unaccompanied by other fungi, with which it is
inextricably mingled. Pure cultures on sterilized blocks caused
only a very slight discoloration.

Cultures started from ascopores rapidly give rise to conidia of
the Cladosporium type. Later on a Graphiwm form appears, pro-
bably G. penicillioides Corda. Perithecia were formed in culture
in about two weeks. Attempts to isolate single ascopores failed
owing to their slimy covering. Cultures from single Graphiwm
conidia only gave conidial forms. Cultures from single Clado-
sporium conidia have, however, given the perithecial stage as well
as the Graphiwm form, and though the author does not consider
the evidence complete owing to the few successful cases, she thinks
that Minch was correct in including a Graphiwim stage in the life-
history of C. piceae.

Witson (M.). The blueing of coniferous timber.—TJ7rais. Roy.
Scot. Arbor. Soc., xxxvi, 1, pp. 82-92, 1922.

This paper is a concise account of the present state of knowledge
of the blueing of coniferous timber, which the author states is
widely distributed in Great Britain with the result that a consider-
able quantity of affected timber is being put on the market. Blued
wood is graded and priced considerably lower than sound timber,
and is frequently rejected for such purposes as pit props, sleepers,
shipbuilding, &e. Its value for furniture construction is also
usually reduced by 25 to 50 per cent.

The fungi most frequently found in blued wood are mentioned,
and details are given of the investigations in other countries as
well as in Great Britain regarding their life-history, the conditions
favouring their attacks, and their effect on the wood.

It is concluded that blued wood is slightly weaker than healthy
timber and should not be used for structural purposes where failure
would result in serious consequences.

Bonar (L.). The life-history of Rosellinia caryae sp. nov. causing
a Hickory canker and disease.—Phytopath., xii, 8, pp. 381-385,
3 figs., 1922.

A disease of hickory (Carya ovata) was found in Michigan in
the spring of 1921. Affected branches showed dead, sunken areas
on otherwise vigorously growing, young shoots. There was a high
percentage of canker among the younger growth. The cankers
varied in size from mere spots to patches 6 in. by 3 in. in diameter,
and nearly always occurred round the leaf scars or on the tips.
Examination of the diseased areas on the younger twigs showed
abundant fruiting bodies of a fungus in the bark, which broke
through the periderm in isolated, small pustules. These proved to

:
be

51

be pyenidial structures, somewhat variable in form, growing imme-
diately beneath the periderm, which ruptures and exposes a black
dome. In section a black, differentiated wall over the top only is
seen. Subsequently, however, the black wall develops downward
all the way round except a narrow portion at the base.

There is no definite ostiole, but the hymenial layer extends over
the entire inner surface of the pycnidium. Hyaline spores, broadly
fusoid, usually containing oil globules, 5 to 7 by 2-5 to 3 w are borne
in great profusion on Indian club-shaped conidiophores. At maturity
the pycnidium ruptures irregularly, the upper carbonaceous part
frequently breaking away and leaving a cup-like cavity.

The fungus grew readily from single spore isolations on sterilized
green bean pods or green bean agar. Pyenidia formed in artificial
culture had a pyenidial wall all the way round, a slight papilla-like
growth similar to an ostiole being observed in some cases. Clean
hickory twigs inoculated with a pure culture of the fungus became
covered with mycelium in which pycnidia formed.

The ascigerous stage of the fungus was developed on naturally
infected twigs, sterilized on the outside with corrosive sublimate
and kept in sterile tubes for six months. Single ascospore cultures
gave rise to the pyenidial stage. The fungus falls into the genus
Rosellinia, and the species being hitherto undescribed the name of
R. caryae is given, together with a technical description. The
imperfect stage agrees with the characteristics of the genus Dothi-
chiza as understood by Diedicke, but, like the other members of
this genus, comes very near Phomopsis.

Scumitz (H.). Studies in wood decay. III. The toxicity of
Western Yellow Pine crude oil to Lenzites saepiaria Fries.—
Journ. Indus. and Engin. Chem., xiv, 7, pp. 617-618, 1922.

Crude western yellow pine oil is a heavy, syrupy liquid, acid in
reaction, and with a sharp, pungent odour. In order to test its
value as a wood preservative, it was added, in concentrations
ranging from 0-5 to 15 per cent., to cultures of Lenzites suepiaria
grown on sawdust from lowland white fir (Abies grandis), Douglas
fir (Pseudotsuga taxifolia), and sugar maple (Acer saccharum).
The culture flasks were kept under observation for three weeks
and examined at frequent intervals. It was found that the toxic
concentration, calculated on the dry weight of the sawdust, was 9
to 10 per cent. in white fir, 10 to 11 per cent. in Douglas fir, and
11 to 12 per cent. in sugar maple. Nine per cent. of the oil was
lost by evaporation when the impregnated sawdust was exposed to
the air for twenty-four hours.

The ideal way of examining the toxicity of wood preservatives
to wood-destroying fungi would be to set up a culture series as
described above, and ascertain the extent of the actual decomposi-
tion of the wood as indicated by the loss in weight in each flask.
There are, however, several drawbacks to such a method, the most
serious of which are the lengthy incubation period (at least three
months) before reliable results would be obtained, and, with volatile
substances (coal-tar creosote, wood tar, &c.), the loss in weight due
to evaporation. The latter objection does not apply to non-volatile

‘substances, such as zine chloride, sodium fluoride, &c., and the method

42

is now in use in connexion with an investigation of the effects of
soil alkali on the rate of decay of wood.

A further experiment on the toxicity of yellow pine oil was
carried out on a medium of hard potato agar, to which the oil was
added in concentrations varying from 0-05 to 1-4 per cent. The
plates were then inoculated from plate cultures of L. saepiaria and
incubated for four weeks at 24°C. The toxic concentration was
found to be between 0-5 and 0-6 per cent. It is apparent from
these results that the toxic properties of western yellow pine oil
are very limited.

Matsumoto (T.). Some experiments with Azuki-Bean mosaic.—
Phytopath., xii, 6, pp. 295-297, 2 figs., 1922.

In July 1921 a considerable amount of mosaic disease was found
among Azuki beans (Phaseolus radiatus var. aurea) at the Morioka
College of Agriculture and Dendrology, Japan. The anatomical
characters of the light and dark green areas in the mottled leaves
are illustrated and briefly described. They are similar to those of
mosaic cucumber leaves as described by Doolittle. It was shown
by tests that the accumulation of starch, and probably also of
sugar, was greater,in the dark than in the light areas. Some
varieties were found to escape the disease, but it was not determined
whether they were entirely immune.

The disease is a typical mosaic, resembling that of the soy-bean.

VAN PoETEREN (N.). Verslag over de Werkzaamheden van den
Plantenziektenkundigen Dienst in de Jaren 1920 en 1921
[Report of the work of the Phytopathological Service during
the years 1920 and 1921.]—Versl. en Meded. Plantenziekten-
kundigen Dienst te Wageningen, 27, 90 pp., 2 pl., 1922.

In this publication is presented a general survey of the incidence
and severity of plant diseases in Holland during the years 1920 and
1921. With the reorganization of the Dutch Phytopathological
Service in 1919 provision has been made for closer contact with the
actual cultivators throughout the country, and a more complete
report of the situation as regards plant diseases in Holland is now
possible than was formerly the case. The staff consists of a director,
four pathologists, an ornithologist, two agricultural and horticultural
consultants, and twenty-four technical officers and inspectors
stationed in different parts of the country, besides administrative
and laboratory assistants. The Institute for Phytopathology at
Wageningen is concentrating on the study of certain diseases of
major importance, the causes of which are insufficiently known, while
the Phytopathological Service, distinct from, but working in close
contact with the Institute, handles all other phytopathological
matters, including the administration of the various legislative
measures dealing with plant diseases and pests. Research work is
not undertaken by the Service unless other duties permit; experi-
mental work, especially in the causation and treatment of disease,
is, however, carried on.

The present report contains a mass of information, and it is
impossible to give more than a brief mention of certain points of
special interest.

Aide

53

CeREALS. The scab and foot rot caused by Gibberella saubinetii
was common on oats. It is noted that, though the Fusarium stage
of this fungus was found attacking wheat, barley, rye, clover, &c.,
perithecia were only observed on oats in Holland previous to 1920,
when they were found on wheat. Seed disinfection with 1 per cent.
uspulun or 0-5 per cent. corrosive sublimate is recommended for this
disease. The perithecia of Pleospora trichostoma were found on the
glumes of germinated grain of barley, the seedlings from which
were affected by stripe disease (Helminthosporium graminewm) and
even on those from which the seedlings, though weakly, were not
marked by definite stripes. It was further found that perithecia
could be induced to form on glumes of unthreshed barley when
incubated for three days in a warm, moist atmosphere, and this
suggests a method of determining whether a sample of grain is
infected by the disease. :

PoTATOES were extensively attacked with streak (‘ stippelstreep-
ziekte’) in the northern part of the country in 1921. Rotting of
the tops of the shoots before they were up was caused by Rhiz-
octonia solant. Tuber disinfection with corrosive sublimate against
the latter disease has now become a practice in some places.

Bret. Severe damage was caused by Peronospora schachtii in
1920 and by Rhizoctonia violacea in 1921.

Fuiax. In 1921 the crops in various parts of Zuid-Beveland were
so severely diseased that they had to be ploughed up. The damage
was apparently caused by an unusually virulent strain of Botrytis
cinerea, which attacked the stalks and even the underground parts,
and was perhaps favoured by the drought.

Fruir. In 1921 Fusarium gemmiperda was found associated
with a disease which destroyed many pear buds, but whether the
disease was due to this fungus or to some physiological cause was
not determined. A purple-coloured decay of the interior of cooking
pears was associated with a fungus which formed pycnidia some-
what resembling Fusicoccum in pure culture. The fungus is
believed to be a new genus. Other rotting pears were found to
bear pycnidia of a Phomopsis (probably Ph. ambigua). Roesleria
hypogaea was found on pear roots (which were extensively rotted
by it) in 1921. This is the first Dutch record of damage caused by
this fungus. Raspberries were attacked by Coniothyriwm fuckelii
and a red Fusarzvwim; good results were got by spraying with
Bordeaux mixture and lime-sulphur. A bacterial disease of cherries,
which appeared to correspond to that described in Flugblatt 39
(1910) of the Biologische Anstalt at Dahlem, was observed in 1920.
Red currants were attacked by Collybia velutipes,a fungus that
may grow for years within the tissues of the branches before
fruetifying on the surface. A species of Coniothyrium is thought
to cause the so-called ‘ marginal blight’ of German sour red currants,
previously reported. A disease of gooseberries, resulting in the
discoloration and death of the twigs, was observed in 1920; a
species of Phytophthora was isolated from the diseased wood and
successful inoculations were obtained. Experiments in the control
of American gooseberry mildew [Sphaerotheca mors-uvae] gave
excellent results with alkaline Burgundy mixture (1-5 kg. copper
sulphate and 1-5 kg. soda [‘sodex’| to 100 litres of water). It

54

should be applied before the first appearance of the mildew. Good
results were also obtained with 3 per cent. carbolineum solution,
but the growth of the plants was arrested for a time.

Amongst the numerous records of diseases in garden vegetables
and ornamental plants may be mentioned a minor disease of bean
pods caused by Isariopsis griseolu; an attack of Phoma oleracea on
Brussels sprouts, the fungus being disseminated with the seed; a

‘spot’ disease of cabbage, very prevalent in 1921 and believed to ‘be
caused by a bacterium; the spinach disease described by Schoevers
in 1918 [ Meded. Landbowwhoos geschool, Wugeningen, xv, p. 75] in
which the same so-called ‘X organisms’ were again found and
thought by Stahel to have an interest in connexion with the
Euphorbia latex flagellates; an attack of a Uvocystis, apparently
U. colchici, on the bulbs of Bulbocodium ver num, of Pythium de
Baryanum op Pelargonium cuttings, Entyloma (2) calendula on
Dahlia leaves, and Diplodia lycopersici on Capsicum annum.

A section of the report is devoted to the effects of the drought of
1921. The dry, hot, summer was favourable to the development of
potato leaf roll and Rhizoctonia solani but unfavourable to the wart
disease parasite, Synchytriwm endobioticum. Tests of a number of
fungicides, chiefly proprietary preparations, ‘are reported. A few
of the more interesting diseases are illustrated.

Mrzce (E.). Observations sur quelques maladies des plantes
cultivées au Maroc en 1921.—|[Notes on some diseases of
cultivated plants in Morocco in eee Bull. Soc. Path. Vég. de
France, ix, 2, pp. 102-108, 1922

Notes are given on the aT Pisrsee of crops observed by
the author in Morocco in 1921. Mildew (Lrystphe graminis) and
the various cereal rusts were severe. No resistance to rust was
noticed in Triticum durum, T. turgidum, or T. monococewm.
Septoria graminewm injured some varieties of wheat and oats, and
Fusarium hordearum Due. was found on barley. The same com-
mon cereal smuts as previously recorded [see this Review 1, p. 34],
were again present.

Potato blight (Phytophthora infestans) caused a good deal of
damage. It appeared first in April on the crop sown in January
and in early December on that sown in October. Alternaria solani
frequently accompanied the Phytophthora. Fusarium solani and
Verticillium albo-atrwm did little damage. Mosaic and leaf roll
were also observed, as well as another disease, believed to be
new, which is more fully described elsewhere [see below p. 86].
Tomatoes were attacked by a Fusarium which caused:a collar rot,
and by a Macrosporium. Leaf roll was also seen on this crop.

Other parasitic fungi observed on cultivated plants included
Cyclogonium oleaginum on olives, Septoria apii on celery,
Uromyces fubae on’ beans (occasionally causing much damage),
Plasmopara viticola and Oidium [Uneinula necator] on vines
(vine mildew severe in certain districts in spite of repeated treat-
ments, and increasing with the extension of European vine-growing ;
Oidiwm common in coastal regions), Melampsora lini on flax (slight),
Cercospora beticola and Uromyces betae wherever beet was grown,
Cercospora violae on violet, and Peronospora trifoliorwm on clover.

By)

Situ (E. F.). Appositional growth in crown-gall tumors and in
cancers.—Reprinted from Journ. of Cancer Research, vii, 1,
49 pp., 4 figs., 28 pl., 1922.

The author has found in various crown gall tumours produced by
Bacterium tumefaciens in tobacco, Chrysanthemum frutescens, and
other plants, that normal tissue cells around the tumour become
converted by division into tumour cells. The phenomenon is figured
in one of his earlier papers but not mentioned in the text. It is
stated to be distinct from the ordinary irritational hyperplasia which
also occurs in the vicinity of many crown galls, in that whereas the
cells in the latter case have a normal arrangement, normal staining
properties, and normal functions, those here described are smaller,
more or less disoriented, and stain and behave like tumour cells.

The particular cases described and very fully illustrated by
photomicrographs in the present paper are the result of fifteen
single, shallow, needle-prick inoculations in the cortex of the stem
of ‘two young, growing tobacco plants, the galls being removed for
examination after three weeks. In all cases there is the plainest
evidence of growth of the tumour ‘by apposition’, that is by the
conversion of adjacent normal cortex cells into tumour cells, of
which a hundred or more may arise from the division of a single
cortex cell. Beyond the tissue in process of active conversion is
an area in which the cortex cells are enlarging (often to twice their
normal diameter) and have large nuclei.

The bearing of these observations on the controversy regarding
the growth of animal cancer tumours by apposition is very fully
discussed, the author ranging himself on the side of those who
believe that such growth takes place. In crown gall he is inclined
to think that growth by apposition is the common form of growth
and that, at least very often, the apparent invasion of surrounding
tissues by the tumour cells and the formation of the ‘tumour
strands’ previously described by him, is the result of appositional
growth in one direction only, a narrow strand of normal tissue
becoming converted by the division of its cells into an extension
of the tumour. Possibly all the tumour strands originate in
this way.

The first stage in the conversion of a normal cortex cell into
tumour cells is the enlargement of the former; then it divides
(apparently always by mitosis) very rapidly, and one can see 4, 8,
or 16 smaller cells enclosed by the stretched and thickened wall of
the original cortex cell. Division goes on until a mass of small
tumour cells, with no intercellular spaces, is formed. Later on
these cells may enlarge so as to equal or even exceed in size those
from which they originated. The stimulus causing these changes
may be a chemico-physical one derived from the bacteria and acting
at a distance from them, or it may be due to a direct transfer of
the bacteria from cell to cell through the pits in the cell walls. The
author believes that the appositional hyperplasia is due to the
latter cause, whereas the hypertrophy prior to division may be due
to the former.

In nearly all the tumours examined in this series, the vascular
cylinder had been split open by the appositional growth of the
tumour along the medullary rays, and the pith was in process of

56

invasion. In certain cases downward extension (in the direction of
the axis of the stem) occurred in a narrow strand along the medul-
lary ray, thus originating a longitudinal tumour strand. In the
outer pith, in some cases, various scattered, small tumours were
found which were not connected in any evident way, such as by the
presence of tumour strands, with the main tumour. The author
supposes that these secondary tumours originated by the liberation
of mobile bacteria from tumour cells, crushed during the splitting
of the vascular cylinder, into the intercellular spaces or fissures in
the neighbourhood, along which they passed to reach torn pith cells
further in, converting the latter into new centres of tumour forma-
tion. The author distinguishes these cases from the formation of
secondary tumours by metastasis, l.e. by the tumour strands
previously described, under the term ‘ pseudometastases ’.

Trost (J. F.). Relation of the character of the endosperm to the
susceptibility of dent Corn to root rotting.—U.S. Dept. of
Agric. Bull., 1062, 7 pp., 2 pl., 1922.

In the course of investigations in Indiana on the various rots of
maize, the ears were classified on the basis of the endosperm with
a view to determining the possibility of the recognition and elimina-
tion of infected ears. Six degrees of starchiness were recognized
and designated as types A to F. Most of the ears studied were
included in the range of types C, D, and E, in which one half, one
quarter, or less of the endosperm was starchy. There was a ten-
dency to greater starchiness in the larger, late-maturing strains
grown in the south of the State than in the northern varieties.

Experiments with a number of varieties showed that the starchy
ears, especially types C and D, were in every case characterized by
a higher percentage of infection from Fusarium spp., Diplodia zeae,
or Penicillium spp. than the horny ears (types E and F). The
average degree of infection in the starchy group was 50-9 per cent.
and in the horny group 33-5 per cent.

It was apparent from an experiment with nine separate strains of
the Reid Yellow Dent variety that the variations in the character
of the endosperm in different ears may be as great within a strain
as among distinct varieties.

In starchy ears a number of factors contribute to the increase of
infection. Starchiness is indicative of immature ears, and in the
late-ripening varieties the less advanced ears are exposed to attack
while maturing under weather conditions more favourable to infec-
tion by the root-rotting organisms. The high moisture content of
immature ears is also more suitable for the development of external
fungi. An unbalanced food supply or a root-rotted condition of
the parent stalk also leads to the ears being starchy, and the latter
is perhaps the most important factor contributing to infection.

Further experiments showed that, in almost every case, the
horny ears produced a higher initial stand in the field, and were
healthier and more vigorous than those with starchy grains, and
this superiority was maintained throughout the growing season.
The yield from the horny grains was also superior to that from
starchy ears, the average decrease in yield incurred through the use
of starchy seed-ears being estimated at 4-2 per cent.

57

The data from the experiments are believed to furnish direct
evidence of the correlation of resistance to root rots, in dent varieties
of maize, with a horny endosperm, and of susceptibility with a
starchy endosperm.

ARMSTRONG (S. F.). The Mendelian inheritance of susceptibility
and resistance to yellow rust (Puccinia glumarum Erikss. et
Henn.) in Wheat.—Journ. Agric. Science, xii, 1, pp. 57-96,
1922.

During 1917-20 a series of experiments on the susceptibility and
resistance to rust of different varieties of wheat was carried out at
Cambridge. Biffen’s investigations (Journ. Agric. Sci.,i, p. 1; ii,
p- 109; and iv, p. 421) showed that resistance to yellow rust was
inherited as a simple Mendelian recessive character, but owing to
the high rate of mortality among his F, plants the validity of his
conclusions was to some extent impaired. The present researches
were intended to clear up the uncertain points.

The varieties chosen for crossing in the main experiment were
Wilhelmina and American Club, which differ in several important
respects—colour of chaff, length of straw, &c.—as well as in their
degree of resistance to yellow rust, American Club being normally
immune while Wilhelmina is moderately susceptible. The F, plants
(1917) derived from this cross were moderately attacked by rust.
With regard to the F, generation (1918), of 829 plants in the
autumn-sown portion, 202 remained rust-free throughout the
season, while the remaining 627 proved more or less susceptible.
These results closely approximate to the 3:1 Mendelian ratio. In
the spring-sown portion the proportion of immune individuals was
less than one quarter of the total number, but, on the other hand,
the number of plants bearing only traces of rust was much higher
than in the autumn-sown crop. The F, plants (1919) were, almost
without exception, more severely attacked than their parents in
the previous year. The year 1919 was particularly favourable to
the spread of rust, which during the cool and moist weather of
July attained the dimensions of an epidemic. It was incidentally
observed in the course of that summer that the more susceptible
varieties are liable to an earlier successful attack than the more
resistant kinds, and also that, at any rate, on susceptible varieties,
yellow rust can make rapid progress in the tissues of the host
during the hottest weather likely to be experienced in England.
The general results obtained from the F, cultures may be briefly
summarized as follows. Up to 10th July the cultures were sharply
divided into three groups. (1) Every plant attacked. (2) No trace
of attack. (3) Extent of attack very variable. The homozygous
susceptible cultures (1) were all characterized by comparatively
early infection, rapid spread of the disease, and exceptional severity
of attack. The homozygous ‘immune’ cultures (2) were character-
ized by remarkable resistance to attack under most adverse condi-
tions and by the extreme lateness and mild nature of the infection
when it did occur. ‘The cultures in which segregation was occurring
(3) occupied an intermediate position as regards the period of infec-
tion and rust spread, though finally a proportion of the plants was
as severely rusted as the homozygous susceptible cultures, while

B2

58

660 out of 3,045 plants had only a slight attack or none. There is
sufficient evidence to show that under very adverse conditions
genetically immune plants may be subject to a mild attack. It
therefore appears safe to conclude that in the segregating cultures
one quarter of the plants were genetically immune, and that these
cultures were the product of F,, heterozygotes for rust resistance.
The results of the F, cultures (1920) bore out the conclusions drawn
from the previous work, the cultures from obviously segregating
F, plants [group (3)| showing definitely that pure resistant, pure
susceptible, and impure susceptible types were present in the F,
cultures, while the groups (1) and (2) above gave respectively badly
rusted and quite or almost quite rust-free plants.

The final conclusion is reached that susceptibility and immunity
behave as unit-characters, and depend primarily on definite charac-
ters which are inherited according to the simple Mendelian Jaw.
This inherited predisposition or resistance to attack is liable to
modification by external environmental factors, such as abnormal
climatic conditions and the application of certain fertilizers. The
greater severity of the attack in 1919 was undoubtedly due in part
to the character of the season. But experiments showed that a
heavy application of nitrate of soda increased the number of infected
plants and the degree of the infection even in the ‘immune’ lines,
Wide spacing also acts in the same direction. In these cases, how-
ever, the success of the parasite was of a very limited nature, and
did not justify the conclusion that resistance could be destroyed
or seriously broken down by the action of such conditions.

The author believes that a re-combination of other inherited
characters in a line homozygous for resistance to rust may modify
the degree of this resistance. Some of these other characters may
obviously modify the metabolism of the plant, and in different
combinations it would appear that they may increase or reduce
susceptibility or stabilize the inherited resistance. Cases are
detailed where factors of this sort appear to have come into play.
and are regarded as affording definite promise of the feasibility of
breeding stable, highly immune strains.

In an attempt to estimate the reduction in yield due to yellow
rust the conclusion is reached that a moderately susceptible variety
may give a yield at least 25 per cent. below that obtainable from
almost precisely the same form when rendered immune.

ZIMMERMANN (H.). 'Typhulapilzbefall der Wintergerste 1921.
[The attack of the Typhula fungus on Winter Barley in 1921. ]
—WNachrichtenbl. deutsch. Planzenschutzdienst, 11, 6, pp. 41-42,
1922.

In Brandenburg, Mecklenburg-Schwerin, and Mecklenburg-
Strelitz the winter barley was found in the early spring of 1921
bearing large numbers of sclerotia of Typhula graminis. The leaf
sheaths and decaying leaf tissues of the young plants were particu-
larly lable to infection. The plants turned yellow and withered.
Eelworms were sometimes also present in the affected plants. Top-
dressings with nitrate of soda and sulphate of ammonia, together
with thorough hoeing and harrowing, greatly improved the condition
of the crop,

59

STEVENS (F. L.). The Helminthosporium foot-rot of Wheat, with
observations on the morphology of Helminthosporium and on
the occurrence of saltation in the genus.—J//inois Dept.
Registr. and Educ., Div. of Nat. Hist. Survey, Bull. xiv, Art v,
pp. 76-185, 23 figs., 25 diagrams, 34 pl., 1922.

In all cases of the Illinois foot-rot of wheat, which has become
known as the ‘ so-called take-all’ disease, examined by the author,
the rotten basal portion of the shoot was found largely occupied by
a hyaline, septate, vacuolar mycelium of irregular thickness, which
grew luxuriantly within the wheat tissue though sparsely on its
surface. The mycelium belongs to a species of Helminthosporium
which is for the present termed Helminthosporiwm No. 1. No
other organism has been found constantly associated with the
disease.

The cultural characters of this fungus were studied in great
detail under various environmental conditions and on numerous
media, the best of which were found to be autoclaved cereal shoots
(especially maize) and corn-meal agar. A marked effect on growth
characters was produced by slight differences in the formulae used
or by variations in the temperature at which the medium was
prepared. The morphological characters of the fungus were also
greatly influenced by environment. The humidity of the medium
and of the atmosphere exerted an important influence on the
production of conidia and their length, on the amount of aerial
mycelium, and on sclerotium formation, the last-named being
favoured by relative dryness. This is important in view of the
fact that sclerotium formation has been suggested as a character
for the separation of certain species. The number and average
length of the conidia were much reduced by comparatively dry
conditions, while their relative variability was considerably in-
creased. Free conidium formation was only obtained at relative
humidities above 90 per cent., and was therefore rare on diseased
plants in the field. Gradual drying out may increase the number
of conidia per conidiophore from the usual 1 to 3 up to as many as
13, Excessive humidity promoted a profuse development of aerial
mycelium. The optimum temperature for the development of the
fungus was about 25°C. Diurnal zonation was marked in many
cultures, but was much influenced by temperature (being absent at
10° C.), nature of the medium, &c. The presence of carbohydrates
in the medium induced a dark coloration of the colonies owing to
profuse sporulation, while striking modifications were observed in
the conidial length, septation, and shape, as a result of variations
in the nutritive or osmotic conditions, Comparisons of colony
characters on artificial media should therefore be made only under
standard conditions and on substrata as nearly as possible identical
in composition. A method for securing this is appended to the
Bulletin.

The mycelium in wheat tissue was often much thicker than that
grown in agar, and occasionally branched in a close, fan-like fashion
on the surface. Some races produced mycelial clumps in culture,
due to a distortion and crowded growth of the aerial mycelial tips.
Anastomoses were frequent. The old aerial mycelium dissolved,
probably by auto-digestion. The conidiophores are single, erect, and

60

darker than the mycelium, and the conidia are borne terminally,
growth being renewed from below each of the successively produced
conidia, which usually fall and leave lateral scars. The length
from base to first scar was 78 to 88 LL.

The colour of the conidia ranges from pale ae to light brown,
sometimes with a faint bluish-green tinge. An extremely short,
black stipe (2 by 4) remains “attached to the basal end after
falling. They germinate readily, usually from the basal ends, the
endospore and septa being apparently consumed during germination.
The exact duration of viability is not known, but the conidia
germinated normally on wheat straw that had remained air-dry for
fourteen months. The conidia are thickest at a point between the
base and the middle. They are described at considerable length,
the concepts ‘ coefficient of longitudinal eccentricity ’ and ‘ coefficient
of cylindricity ’ being introduced for purposes of greater accuracy.
Conidial length, breadth, and septation are studied biometrically
and compared with the corresponding characters of H. ravenelit.
The average dimensions and septation observed by the author in
the case of Helminthosporiwm No. 1 on wheat were as follows:
length, 76-8 «7; breadth, 20-4 ~; septa, 7-9.

Inoculation experiments were carried out on maize, wheat, oats,
barley, and rye, sixteen other species and strains of Helmintho-
sporium being used for comparison with H. No.1. The results of
these preliminary tests indicate a wide difference in the suscepti-
bility of cereals to rot by the various forms of Helminthosporium,
oats being the least liable to infection, and maize and wheat the
most. H. No. 1 completely rotted a wheat shoot 11 mm. long in
five days, maize was rotted less rapidly, and oats, barley, and rye
still less; while H. ravenelii produced no decay on any cereal.
Several other strains showed high rotting power on wheat shoots,
especially H. teres and H. sativum both isolated from barley, and
H. No. 9 isolated from wheat. H. cuterseminatum from the
Centraal Bureau voor Schimmelcultures also caused a rot of wheat.
Numerous inoculations of seedlings in Petri dishes, in ‘rag doll’
germinators, and in soil all gave positive results with H. No. 1, the
cells of leaf- sheath, stem, and root being rapidly invaded.

Appressoria are formed by the germ-tube prior to penetration,
and the cell wall of the epidermis is pierced by a fine infection
hypha from the appressorium, a callus-like swelling being formed
on the inside of the cell wall. The mycelium grows S rapidly within
the host cells, often forming a dense mass resembling a pseudo-
parenchyma. Other hosts susceptible to the rot caused by H. No. 1,
besides those mentioned above, were sorghum, Sudan grass, and
millet (Setaria italica).

Saltation, a term used by the author because of the existing
differences in the definition and usage of the term mutation, is much
in evidence in certain races of Helminthospori ium, and is exhibited
by the appearance of a sector differing from the rest of the colony
in various characters ; rate of growth, degree of conidial production,
length, breadth, septation, and shape ‘of the conidia, density, colour,
and zonation of the mycelium, and sclerotium formation. Certain
saltants far exceeded the accepted specific limits in divergence from
their parent. The correlation of certain characters in. saltation

61

was observed; thus, colonies of slow linear growth were usually
high in conidial production and vice versa. In other cases rapid
growth or slow conidial production, verging on sterility, was coupled
with paleness of colour; and the development of much aerial

mycelium was accompanied by low conidial production. In the
main the saltants were permanent in character in subculture.
Occasional reversions to the originals occurred, but in no case
where the true saltant character was established by constancy
through several transfers did the whole stock revert. All attempts
to secure artificial saltation by various means failed. Single-
conidium cultures gave rise to numerous saltations. As compared
with bud-variation on potatoes and tobacco, saltation in Helmintho-
sporium is of very frequent occurrence. One hundred and twenty-
six variant sectors were studied, and this number might easily have
been doubled or trebled. Even supposing some of the forms to
have been mere modifications, there was a large proportion of
permanent saltants. The author believes that several of the strains
received from correspondents were saltants from the original form
isolated. A general discussion on saltation and mutation in fungi
is given, with references to the work of various investigators.

The author places in the general type H. sativwm the following
elementary species: H. No. 1. la, 1b, 1¢, and 1d (isolations from
foot-rot in Illinois); also his numbers 3 to 9, 11 to 19, 22 to 27, 34,
37, 38, 42, and 43. These include forms sent by correspondents as
H, sativum, H. teres, H. gramineum, and H. avenue. H. No. 20 is an
instance of saltation sufficiently pronounced to remove the organism
entirely from the group under discussion, though it was descended
from Bakke’s isolations of H. sativum. H. ravenelii is a pe ee
type. Other apparently distinct types are briefly described,
cluding one causing a disease of wheat in the Sudan which is allied
to a form isolated by the author from Setaria ttalica. In the
author's opinion tenable distinctive diagnoses could be drawn up,
through the methods of biometry-and a study of biological relations
and cultural characters, for many races of Helminthosporiwm on
the principal cereals, but whether they should be given distinctive
specific names is a question of utility.

A bibliography of 129 entries is appended, and the work is
illustrated chiefly by photographs and photomicrographs.

Paxton (G. E.). Studies on Helminthosporium species found on
cultivated Barley in California.—Abs. in Phytopath., xii, 9,
pp. 446-447, 1922.

The perithecial stage of Helminthosporiwm gramineum was
found in California on barley straw two years old. Cultures ob-
tained from the ascospores yielded typical H. graminewm conidia
and inoculations with the same gave typical lesions of this species.
A culture bearing conidia was also obtained from herbarium
specimens of H. graminewm sixteen years old.

Helminthosporium sativum from barley was grown in pure
culture and successfully inoculated on Hordewm muranium and
vice versa. The optimum temperature for this fungus is about
30° C.

62

Fawcert (G. L.). La ‘gomosis’ de los Naranjos. [‘Gummosis’ of
Orange trees.|-—Rev. Indust. y Agric. de Tucwmdn, xii,
11-12, pp. 149-155, 5 figs., 1922

This is a semi-popular account of gummosis of citrus trees, as it
occurs in the province of Tucuman, in Argentina. The author
distinguishes two forms of the disease: one, which affects the stem
at soil level and the root system just below the collar, producing
the well-known foot-rot. and another, less common, which is con-
fined to the trunk and branches. The a is due to the attack of

for vm eae w chile ¢ a sien (a form of iY ectria iG oma)
is sometimes found but is less often parasitic. The disease chietly
attacks trees that have not been budded and has destroyed large
numbers of these. Several factors which predispose to it are
known, the chief being excessive soil moisture, too deep planting,
and faulty methods of irrigation. Gumming of bitter orange trees
is believed to be unknown, hence the frequency with which they
are used as stocks. Where foot-rot has not made excessive progress,
exposing the roots around the collar and excising diseased parts is
recommended. The author states that the healing of the wounds
thus produced is often more satisfactory when they are exposed to
the action of air and light without employing disinfectants, If the
latter are used, he recommends Bordeaux paste. The roots may be
left exposed for a week or two.

The second form of gummosis is found sometimes on orange trees.
Where these are ovafted on bitter oranges the affection ‘extends
downwards until it is arrested at the union of the two varieties,
and this would seem to indicate that grafting at high levels is of
advantage. The cause of this form of the disease may be different
from that of foot rot, but it has not been fully studied as yet.

McLean (F. T.) & Ler (H. A.). Pressures required to cause

stomatal selectins with the Citrus-canker organism. — Philipp.
Journ. of Science, xx, 3, pp. 309-3820, 2 figs., 1922.

The authors have shown in previous papers that the resistance
to canker (Pseudomonas citri) of the mandarin orange is due to
some character in the epidermis of that species [see this Review, i,
p. 12], and that the stomata of the resistant mandarin orange differ
considerably in structure from those of such a very susceptible species
as the grapefruit. These and other investigations suggested that
resistance is largely determined by differences in the structure of
the stomata and in the degree of their permeability to water. It
was decided to test this theory by introducing the canker bacteria
into the leaf tissue of the resistant mandarin orange without
mechanical injury, and a method was devised of drawing water,
containing a suspension of the bacteria, into intact leaves on the
tree in the orchard by known and easily measurable pressure. The
contrivance employed was an adaptation of the porometer, the con-
struction and mechanism of which are described.

During the dry season (April and May) of 1921, tests were made
of the pressure required to inject water alone into citrus leaves by
means of the above apparatus. It was ascertained that the degree

63

of permeability, as judged by visible injection resulting in the
appearance of translucent spots, varied greatly in leaves of the same
age and on the same tree. Of the citrus varieties tested, the
Szinkom mandarin orange, believed to be a native of China, is one
of the most canker-resistant horticultural varieties of any species.
The grapefruit trees on which the tests were carried out belonged
both to the Pernambuco and seedling varieties, and were supple-
mented by a susceptible type of East Indian pomelo. The susceptible
Pernambuco grapefruit and the pomelo were the easiest to inject
(average pressures required 19-5 em. and 19-6 cm. respectively), the
highly resistant Szinkom mandarin orange the most difficult (average
pressure 33-6 cm.), and the moderately ‘resistant Washington navel
intermediate (average pressure 20-8 cm.). These comparative figures
indicate that visible injection pressure is an approximate index of
resistance to citrus canker.

A suspension of Pseudomonas citr’ was then substituted for the
water-bath immersion, young, and therefore susceptible, leaves
being used. The temperature of the suspension varied between 28°
and 31° C. In the Szinkom mandarin orange infection of the leaves
did not usually result until the pressure recorded by 10 em. of
mercury was reached during injection and was not general below
19 or 20 cm., whereas in the grapefruit and pomelo it took place
either without pressure or at a very low pressure. The water con-
taining canker organisms was drawn into the leaf tissues at lower
pressures than those causing visible injection. The pressure causing
visible injection thus appears to be roughly proportionate to, but
not identical with, that necessary for infection.

It is evident from the results of the experiments that canker will
develop in the leaves of the mandarin orange once the bacteria have
gained adinission to the leaf, even in the absence of injury to the
tissues. It has already been shown in the earlier paper, referred
to above, that the stomata of the mandarin orange were so con-
structed as to preclude the ready ingress of water. ‘The experiments
described in the present paper indicate that pressure is necessary
for the absorption of water by the stomata of the mandarin orange.
On the other hand, the stomata of the grapefruit are constructed in
such a way that simple i immersion in water containing the bacteria
is sufficient to cause infection.

Lee (H. A.). Relation of the age of Citrus tissues to the
susceptibility to Citrus canker.—DPhilipp. Jowrn. of Science,
xx, 3, pp. 331-339, 4 pl., 1922. .

In an earlier paper (Phytopath., xi, p. 70, 1921) the author
demonstrated the correlation between advancing maturity and an
increasing degree of resistance to citrus canker (Pseudomonas citr).
The present article describes inoculation experiments undertaken in
1918-19 to gauge the amounts of canker occurring at different stages
of maturity. Preliminary tests were conducted in the Philippines
on fruits of the pineapple orange (Citrus sinensis) and the Valencia
orange. ‘lhe fruits were inoculated from the same suspension of
cultures of the bacillus, and maintained under identical environ-
mental conditions favourable for canker formation. The resulting
data showed very considerable susceptibility for fruits of a small

64.

diameter, while large fruits approaching maturity were but slightly,
if at all, affected.

The experiments were continued in the Nagasaki Prefecture,
Japan, on fruits of the Washington navel orange. The fruits were
inoculated when the petals dropped in late May and early June, and
again at different periods as they approached maturity. The tissues
became virtually immune as the fruit ripened. Tests were also
carried out on several strains of the Unshiu (Satsuma) orange (Citrus
nobilis var. wnshiu). It was ascertained that the total period of
possible infection for the Unshiu oranges did not exceed 98 days, as
compared with 115 to 120 days for the Washington navel. Further
data point to a longer period of susceptibility for the fruit tissues
of the grapefruit [Citr us maxima (decumana)| than for either the
Washington navel or the Unshiu oranges.

Exact information on the increase in resistance with advancing
maturity of the foliage tissues is very difficult to obtain and of
less practical importance. The results of experiments conducted on
young, intermediate, and fully matured leaves show that the latter
are entirely resistant, the amounts of infection decreasing as the
tinal stages of development are reached. In all the experiments
inoculations were made both by means of needle punctures and
without puncturing (stomatal infections)., The fruits were suscep-
tible to the former for a longer period than to the latter.

The results from this work materially affect field practice for the
prevention of canker. In western Japan the fruits of the Washington
navel orange are virtually immune from stomatal infection after
85 days and wound infection after 110 to 120 days. Preventive
methods may therefore be largely confined to the period from June
to August. “Canker on Unshiu oranges is uncommon in Japan,
being almost negligible from the growers’ point of view, and the
results with this var iety are of less practical interest.

Sprnosa (J. P.). Apuntes sobre el cultivo del Naranjo referidos
especialmente al Territorio Nacional de Misiones. [N otes on
the cultivation of Orange trees, with special reference to the
National Territory of Misiones.|— Bol. Minis. Agric. Nacion.
(Argentina), xxvii, 1, pp. 3-185, 31 illus., 1922.

This article has been written with the object of attracting citrus
growers to the province of Misiones, in Argentina, where climatic
and other conditions are highly favourable “to the dev elopment of
this industry. A chapter is devoted to pests and diseases, with full
descriptions of symptoms and advice as to the most effective
remedial measures.

Amongst fungous diseases, sooty mould is commonly found in
the wake of scale and similar insects, though the author states
that there are cases where its presence is. traceable to purely
physiological causes. Spraying with Bordeaux mixture, to which
1 per cent. tobacco extract has been added, has given uniformly
good results when the trouble has been due to insect attack. When,
however, it originates in excess of humidity and lack of aeration
and light, cultural measures to remedy these defects will check it.

Gummosis is a very common disease and a formidable problem in
many plantations. ‘The worst outbreaks occur in localities where

65

conditions generally tend to encourage vigorous growth. The
province of Corrientes is at present the greatest sufferer, whole
regions having been devastated by this terrible scourge, but its
occurrence in other provinces in a more or less virulent form has
been observed, and it is feared that the present rapid rate of pro-
gress of the disease may eventually kill the industry altogether,
unless energetic measures for combating it are taken. Unfortunately
the cause of the disease has not been traced with absolute certainty
so far, some ascribing it to parasitic action and others to purely
physiological causes. The characters of the disease are described
and methods for-its control discussed. These should include plant-
ing in high, well-drained, loamy soil, with a deep and permeable
subsoil, to permit vigorous root development; choice of stocks such
as the bitter or Seville orange [C. bigaradia], the rough brown
lemon [C. sp.], C. trifoliata, and C. myrtifolia, which are known
to be resistant; and good cultivation. The treatment of affected
plants by opening up the collar and main roots and cutting away
the diseased tissues, followed by antiseptic treatment of the exposed
parts, is recommended.

The author states that in northern Argentina shade is required
in the citrus plantations, free exposure to the sun favouring the
development of gummosis. Cases are quoted of severe attacks of
gummosis following the removal of shade in forest clearings in which
wild and semi-wild citrus plants had been retained. Under normal
forest conditions these trees are not attacked. He considers that
the primary cause of gummosis is unbalanced water relations in the
plant, though invasion by parasitic organisms may accentuate the
effects.

Other diseases appear to be of minor importance.

Horne (T.). A Phomopsis in Grape Fruit from the Isle of Pines,
W.I., with notes on Diplodia natalensis.—Phytopath., xii, 9,
pp. 414418, 2 pl., 1 fig., 1922.

In a cargo of grapefruits shipped from the Isle of Pines, W.L.,
two fruits with a tan-coloured rot were obtained on arrival at San
Francisco. From the first Diplodia natalensis was isolated, and
produced stem-end rot in grapefruits and oranges on inoculation.
The other yielded the more delicate, white mycelium of a Phomopsis.
In the later stages of rotting caused by this fungus the colour was
uniformly smoky-brown below the surface, in contrast with the
black colour shown by the Diplodia at the same level.

The Phomopsis, which is considered to be a new species and
named P. caribaea, gives a white mycelium, sometimes becoming
slightly tinted brown, in culture. Dark brown sclerotial bodies,
less than 0-5 mm. in diameter, are formed in some media, small,
conical pyenidia in others. The lower (newer and moister) pyenidia
in the tube cultures mostly bear the scolecospores or B-spores, 20 to
32 by 1», while the upper pycnidia bear chiefly the pyenospores or
A-spores, 5-6 to 8 by 2-2 to 3 yu.

Tnoculations on grapefruit caused the development of a typical
stem-end rot in several cases, though the rot was not fully developed
until after about three months. On oranges the parasitism of the
fungus was doubtful.

B38

66

Facwett (H. 8.). A new Phomopsis of Citrus in California.—
Phytopath., xii, 9, pp. 419-424, 2 figs., 1922.

From citrus fruits affected with stem-end rot in packing houses
in Santa Barbara County a Phomopsis was isolated. The trouble
appeared to be of minor importance, only fruits picked when quite
mature or stored for a long time being very occasionally attacked.
No fruit with stem-end rot was found in the orchards, but Pho-
mopsis pyenidia were discovered on a few dead twigs, and some
leaves gave indication of melanose, a condition which, in Florida,
is characteristic of attack by Phomopsis citri. Some mature fruits
picked from branches containing dead twigs, and kept in the
laboratory, developed stem-end rot in about five weeks. The
fungus was commonly found in the bark of lemon trees affected
with ‘shell bark’, and from inoculation tests it would appear not
improbable that it is a factor in the development of the shell bark
disease.

Inoculation experiments are described which indicate that the
fungus differs from P. citri, the species responsible for stem-end rot
in Florida. The weaker virulence of the Californian fungus, its
lower optimum temperature for growth (20-5° C. as against 24° C.),
differences in mycelial growth (fan-like, irregular, surface growth,
turning brown on potato and cornmeal agar), and spore production
(B-spores predominating on a variety of culture media), have led
the author to form a new species P. californica. This cannot be
distinguished from P. citri by spore measurements alone.

Rast (L. E.). Control of Cotton wilt by the use of potash fertili-
zers.— Journ. Amer. Soc. Agron., xiv, 6, pp. 222-224, 3 figs.,
1922.

During the spring of 1920 several five-acre fertilizer experiments
were conducted on different cotton plantations on alluvial river
land. Different combinations of fertilizers were used at each place,
at the rate of 500 lb. per acre. One grower used a mixture con-
taining 10 per cent. phosphoric acid, 3 per cent. nitrogen, and no
potash. In his fields the cotton plants on both the fertilized and
unfertilized areas died to such an extent that no record was kept
of the yield. In the spring of 1921 equal parts of the same ferti-
lizer and of kainit containing 12-5 per cent. potash were mixed and
applied to a portion of this area, at the rate of 1,000 lb. per acre,
before planting. The plants on the unfertilized area began to die
long before reaching maturity, and by harvest time 95 per cent.
were dead, evidently as the result of an attack of wilt [Fusariwn
vasinfectum). There was not a single death on the corresponding
area to which the complete fertilizer was applied. The fertilized
area produced 1,127 lb. of seed cotton per acre as against 225 lb. on
the infected, unfertilized part of the field, Plants on an adjoining
area, to which the same combination as in 1920 was applied before
planting, but which was given an additional 500 Ib. per acre of
kainit after the plants were up, were equally resistant and prolific.

The writer believes that this control of cotton wilt was due to
the potash in the fertilizer. The identification of the disease was
confirmed by Dr. J. A. Elliott, Plant Pathologist at the Arkansas
Experiment Station. The experiments will be continued with

67

various kinds and quantities of potash, both alone and in combina-
tion with other plant foods.

JONES (L. R.) & TrspaLe (W. B.), The influence of soil tempera-
ture upon the development of Flax wilt.—Phytopath., xii, 9,
pp. 409-4138, 1 fig., 1922.

This paper records further studies in continuation of the earlier
work of W. H. Tisdale (Journ. Agric. Res., x1, pp. 573-607, 1917),
carried out with the improved Wisconsin soil temperature tanks,
on the effeet of soil temperature on the rate of infection by the flax
wilt organism, Fusarvwi lini. Soil was inoculated with a pure
culture of this organism, and placed in tanks held at temperatures
of 12°, 14°, 16°, 20°, 24°, 28°, 31°, 34°, and 38° C., one hundred flax
seeds being planted in each case. The controls were sterilized.
The optimum temperature for infection was 24°C., no infection
oceurring at 12° or at 38°. The critical temperature—determined
by W. H. Tisdale as 14° to 16°—was tested in a third series of
experiments with soil readings of 14° to 15° and of 16°. In the
former tank only one plant showed slight symptoms, whilst in the
latter 22 per cent. of the plants were affected. The delicacy of
the temperature balance was further shown when the tanks held at
14° to 15° were raised to 16°; within a week 15 per cent. of the
plants showed wilt symptoms. The upper temperature limit is
almost as strongly defined as the lower, 67 per cent. of the plants
wilting at 34° and none at 38°C. The temperature curve for the
disease corresponds closely with that for the growth of the parasite.

Comparing the temperature.relations of the very similar Fusarium
diseases of flax, cabbage, and tomato, it is noted that the lower, or
critical, temperatures for infection stand in some relation to the
optimum temperatures for the hosts, the tomato being a warmer
climate plant than cabbage, and still more so than flax, while the
critical temperatures for their Fusariwm wilts are 19°, 16° to 17°,
and 14°C. respectively. The geographical distribution of these
diseases in the Mississippi valley agrees broadly with these results,
tomato wilt being confined to the southern States with its northern
range in the latitude of central Illinois, while the maximum viru-
lence of cabbage yellow lies between Ohio to lowa and Southern
Wisconsin, and flax wilt extends to the northern boundary of the
United States, and probably into Canada.

Hau (T. R.). Disease factor in commercial pomology.— Detter
Fruit, xvii, 2, pp. 5, 6, & 18, 1922.

Instructions are given as to the best methods to employ in the
harvesting, storage, and transportation of fruits. It is estimated
that careless handling in picking, grading, &c., may reduce the
market value of fruit by 50 to 75 per cent. In the case of the more
perishable fruits (apple, pear, quince, cherry, lemon, citron, lime,
plum, persimmon, grape, strawberry, and fig) the stem should not
be pulled out, as the skins are apt to break and admit fungi and
bacteria. The stems may safely be removed from the orange,
pomelo, peach, apricot, prune, olive, raspberry, dewberry, almond,
and walnut. It is extremely important to ascertain the exact stage
of maturity for successful picking, and brief directions are given by

68

which the state of the different fruits may be tested. The construc-
tion of packing-cases and the wrapping of the fruits are also
described. Oiled apple wraps have been found to retard the lite
processes considerably, thereby increasing the length of time during
which the fruit may safely be kept, besides preventing the dis-
semination of spores. Low and even temperatures (31° to 32° F.)
are also essential during storage and transit. Such blemishes as
scald, soft scald, and Jonathan spot may be prevented by these
means. Ice scald appears to be due to insufficient oxygen and an
accumulation of carbon dioxide within the paper wrappers of
peaches, and may be prevented by good ventilation with refrigera-
tion. The water content of most fruits ranges from 80 to 84 per
cent., and the atmospheric humidity should not exceed this figure,
otherwise moisture will collect on the surface of the fruit and
facilitate the action of decay organisms.

Unsuitable conditions of transit frequently impair the resistance
of the fruit considerably. The car should be loaded to secure the
maximum ventilation, refrigeration, and stability. The packages
should be spaced widely enough apart to allow a free circulation
of air, but not to permit shifting. False flooring should be installed
to promote the maximum circulation around and through the load.
The top tier of packages should be below the line of safe refrigera-
tion and well within the cooler portion of the car.

CunNINGHAM (G. H.). Silver-blight, Stereum purpureum Pers.,
its appearance, cause, and preventive treatment.— New Zea-
land Journ. of Agric., xxiv, 5, pp. 276-283, 8 figs., 1922.

The symptoms of silver leaf, which is common in New Zealand
orchards, are described, and also the life-history of the causal
organism (Stereum purpureum). In apple orchards it is said to
cause a loss of about 1 per cent., on pears even less, but on apricots,
peaches and plums, the loss may be well over 10 per cent. It is
pointed out that fructifications may be produced in New Zealand
at any time of the year, but are found especially during wet weather
or in damp localities. The life of the fructification, which produces
spores at intervals, may last for several seasons. The spores are
the sole means of dissemination of the fungus, and they can
only enter the tissues of a tree through some kind of wound or
bark injury. The disease can therefore be combated by the removal
and destruction of all dead stumps bearing Sterewm fructifications,
and by the dressing of wounds with coal-tar. Spraying is quite
useless, as the internal mycelium cannot be reached by such means,
and the injection into the tree of substances toxic to the fungus
has also failed.

McKay (M. B.). Thielavia basicola on watermelon in Oregon.—
Abs. in Phytopath., xii, 9, p. 445, 1922.

During 1916 diseased watermelon plants were received from
Oregon which showed the older leaves turning brown and drying
up from the centre of the hill outward, the leaves on the young
portions of the runners (then about 18 in. long) being apparently
unaffected. The outer tissues of the main stalk, from 1 to 4 in.
below the ground, were sometimes severely disintegrated, and had

69

a scurfy appearance. This diseased tissue contained chlamydospores,
and on culturing yielded Thielavia basicola. Inoculations of water-
melon seedlings gave a vigorous rot in two weeks. This disease
was reported on watermelons from Utah by O’Gara in 1915.

LAIDLAW (W,) & BRITTLEBANK (C. C.). Brown rot of stone fruits.—
Journ. Dept. Agric. Victoria, xx, 7, pp. 442-443, 1922.

A series of experiments in the control of brown rot (Sclerotinia
cinerea), a Short description of which is given, was carried out at
Bairnsdale, Victoria, in 1921. The disease was extremely severe
in the season 1920-21, over 75 per cent. of the peaches in the
locality mentioned being destroyed. The following sprays were
used on July 28, when the trees were dormant: commercial lime-
sulphur, 1 in 9; copper-soda [Burgundy mixture] 6:9:40, Bor-
deaux mixture, 6:9:40; neutral copper acetate, 3 lb. to 40 galls. ;
copper sulphate, 1 in 10. A second spraying was given when the
buds were showing pink, the following being used in place of the
above in the same order: commercial lime-sulphur, 1 in 20; copper-
soda, 3:44:40; Bordeaux mixture, 3: 2:40; neutral copper acetate,
3 lb. to 60 galls.; atomic sulphur, 1 in 10 (used in place of copper
sulphate). Three or four weeks before the fruit was ready for
picking it was sprayed again, lime-sulphur 1 in 30 and 1 in 40 and
atomic sulphur 6 lb. to 60 galls. being used. In the case of the
copper-soda, Bordeaux, and copper acetate plots, an extra application
of self-boiled lime-sulphur 8:8:50 was given five weeks after the
second spray.

The peach varieties treated were Pullar’s Cling, Tuscans, and
Goodman’s Choice. The best results were obtained with commercial
lime-sulphur, the trees being free from brown rot, peach aphis, and
leaf injury. Bordeaux and copper-soda also gave very satisfactory
results. Copper sulphate and copper acetate were the least effective.

GARBOWSKI (L.). La lutte contre le blanc du groseillier (Sphaero-
theca mors-uvae Berk. et Curt.). {The struggle against Goose-
berry mildew (Sphaerotheca mors-wvae Berk. & Curt.).]—Bull.
Soc, Myc. de France, xxxviii, 2, pp. 98-99, 1922.

This is an account of spraying tests carried out at the Experi-
ment Station for Pomology at Sympheropol (Crimea) m 1917 and
1918. The experiments are stated to have demonstrated the
superiority of weak solutions of arsenite of soda (0-01 to 0-02 per
cent.) Over various concentrations of polysulphides (lime-sulphur
solutions)—long held to be the best remedy—and over powdered
sulphur in the treatment of American gooseberry mildew. In prac-
tice powdered sulphur acts exclusively on the foliage, and almost
entirely fails to protect the fruit from infection.

The percentage of bushes bearing contaminated fruits was 51
in those sprayed with arsenite of soda, 83 in those receiving lime-
sulphur, and 100 in the controls, which were very heavily attacked.
The advantages of the first over the second treatment stand out
even more clearly when the comparison is applied to the berries
picked from the treated plants. Four degrees of infection were
recorded : (1) perfectly healthy berries with no trace of mildew ;
(2) slightly affected, with small spots; (3) more severely attacked ;

70

(4) very severely attacked, more than half the surface being covered
with mildew spots. Marking these degrees as 0, 1, 2, and 3, and
taking the infection on the controls to be equal to 100, plants
treated with lime-sulphur had an infection figure of 65, while those
treated with arsenite of soda had only 28. In comparing the
weight of the berries, the difference is still further accentuated, the
average weight of healthy berries on each bush being 80-4 per cent.
of the total weight with arsenite, 36-6 per cent. with lime-sulphur,
and only 3-1 per cent. in the controls.

It is unfortunately the case that arsenite of soda (like lime-
sulphur), even in very dilute concentrations, causes burning of the
foliage, but the amount of this varies in different varieties. Amongst
25 [unnamed] varieties examined, some retained their foliage un-
injured, while others suffered severe burns, or even lost a portion
of their leaves.

PcuTTeRILt (V. A.).. Plant diseases in the Western Provinces.
IV. Two diseases of the Loquat.—Jowrn. Dept. Agric. S. Africa,
iv, 4, pp. 832-3837, 7 figs., 1922.

The loquat (Hriobotrya japonica) is very common in gardens
round Cape Town, and a leaf scab, due to a species of Fusicladium,
was first reported on it from Kenilworth, Capetown, in 1920. In
the following year affected fruit was examined, and it was found
that loquat scab is very similar to those of the apple and pear
[Venturia inaequalis and V. pirina|. The author thinks that the
disease cannot have existed in South Africa for more than nine or
ten years. It causes dark olive-green, velvety spots on the under
side of the leaves, frequently distorting them, and also produces
markings on the fruit which are very similar to those found on
scabbed apples. It is not known whether the fungus overwinters
on old leaves, as is the case with the allied scabs of other pomaceous
fruits, but the loquat being an evergreen this means of bridging
the seasons appears hardly necessary. In controlling loquat scab
on the lines already known to be effective against pear scab in the
Western Province, the method of leaf renewal demands a more
frequent application of either Bordeaux (4-4—50) or lime-sulphur
(1 in 45), than is the case with the pear, where the complete shedding
of the foliage in the autumn facilitates treatment. From April
onwards the frequency of the sprayings will depend on the intensity
of the disease and on weather conditions, but up to maturity both
the fruit and foliage should always have a protective coating of
fungicide. From November to April, which is the dry season,
sprayings can be reduced to once every two months. Clean culti-
vation is recommended, and badly diseased twigs should be cut out
and burned.

A blight of loquats caused by Entomosporiuwi sp., which has so
far only been reported from one locality in Cape Province, was
found associated with scab. Jt is also known in other parts of the
Union outside the Cape Province. The first symptoms are the
appearance of small, circular, shiny, black spots, somewhat convex
in shape, which appear on the fruit, while small, cireular, reddish-
brown spots, surrounded by a yellow zone, stud the leaves, being
much less noticeable than the scab markings due to Fusicladium.

71

It is only when the spots on the fruits are numerous and aggregated
into patches that the two diseases can be confused. A similar, if
not the same species of Entomosporium (E£. maculatum with its
perfect stage Fabraea maculata) causes leaf blight of the quince
and pear, considerable damage from’it having been recorded in
South Africa, particularly in Natal and in the Orange Free State.

The control measures advocated for scab should apply equally
well to this blight, owing to the similarity of the two fungi. It is
thought that blight will be more readily controlled than scab,
judging by the relative prevalence and severity of the two allied
pear diseases, under the prevailing climatic conditions of the
Province.

Derton (W. C.) & Jounston (S.). Dusting and spraying experi-
ments of 1920 and 1921.—WMichigan Agric. Exper. Stat.
Special Bull. 115, 54 pp., 23 figs., 1922.

In this bulletin a long series of dusting and spraying experiments
carried out in 1920 and 1921 is described. The first experiment
arose from the general practice of growers in Michigan of waiting
until the blossom buds have separated (pinking or cluster stage)
before spraying for apple scab. Observations indicated that scab
infection occurred previous to this, and more information was
desired as to the value of spraying at the pre-pinking stage (when
the buds first show colour, but before they separate). Three plots
were selected for experiment; the first was sprayed according to
the normal practice, the second was similarly treated, but an extra
spray given at the pre-pinking stage, and a third plot was left as
control. Lime-sulphur was used (14 in 50), and the results gave
46 per cent. seabbed for plot 1, 16 per cent. for plot 2, and 100 per
cent. for the control.

The second series of trials was carried out to obtain information
as to the comparative value of dusting and spraying in controlling
apple scab and codlin moth. The 1920 experiment was made on
100 twelve year old Grimes Golden trees which were divided into
four plots, the first being used as a control, the second sprayed with
dilute lime-sulphur with lead arsenate, the third with sulphur-
arsenate dust (90 per cent. sulphur, 10 per cent. dry lead arsenate),
and the fourth with lime-copper-arsenate dust (80 per cent. hydrated
lime, 10 per cent. anhydrous copper sulphate, and 10 per cent. lead
arsenate). Four sprayings were applied, and the plots gave 89, 20,
22, and 68 per cent. scab and 10-0, 1-9, 0-5 and 5-0 per cent. codling
moth respectively. Lime-sulphur-arsenate solution and sulphur-
arsenate dust gavé therefore much better results than lime-copper-
arsenate dust, but the control of scab was not entirely satisfactory
in any case. The fruit was tested on a very high standard ; many
of the apples would not have been classed as scabby commercially.

The 1921 experiment was similar, but the lme-copper-arsenate
dust was omitted. The control gave 75 per cent. scab and 34 per
cent. codling moth, the sprayed plot [four times with lime-sulphur
(12-50) with lead arsenate, and once with Bordeaux with lead
arsenate] 8 and 5 per cent. respectively, and the dusted plot [six
times with sulphur-arsenate dust (90-10)] gave 8 and 12 per
cent. The figures showed that dusting and spraying gave equally

72

satisfactory control of scab, but that the control of codlin moth by
dusting was not so good as by spraying. A further dusting test
was made in 1921: sulphur-lime-arsenate of lead dust (80-10-10)
being used and seven dustings given. The controls gave 24 to 84
per cent. scabby, and 4 to 41 per cent. wormy fruits, while the
dusted area gave 4 to 14 per cent. scabby (except on the late
blooming variety Delicious which gave 51) and 7 to 14 per cent.
wormy.

To oe up the results of the above dusting trials, sulphur dust,
used according to the regular summer schedule, has given satis-
factory control of apple scab. Lime-copper-arsenate dust, in the
proportions used, has not so far proved successful.

Experiments on pear scab [Venturia pirina| were undertaken
in 1920 to ascertain whether more than three sprayings are neces-
sary to control this disease, and to compare the respective efficiency
of lime-sulphur, sulphur dust, and copper sulphate dust (containing
10 per cent. dehydrated copper sulphate), lead arsenate being added
to these materials when necessary. Four applications were given—
at pre-pinking, pinking, calyx stage (just after the petals had
dropped), and about a fortnight later.

In the first experiment, lime-sulphur (1-50) gave 10 per cent.
scabbed; sulphur dust (omitting the last dusting) 15 per cent.,
and (omitting the pre-pinking dusting) 22 per cent.; copper
sulphate dust 23 per cent.; and the control 58 per cent.

In the second experiment, lime-sulphur (1-40) gave 16 per cent. ;
sulphur dust (4 dustings) 10 per cent. ; copper sulphate dust 20 per
cent.; and the control 60 per cent.

In the third experiment three dustings [sulphur alone ; sulphur-
lead arsenate-nicotine sulphate; sulphur-lead arsenate (90-10)]
gave 1-9 per cent. scabby and 0:5 per cent. wormy, while three
sprayings (Bordeaux; lime-sulphur (1-40)-lead arsenate—Black-
leaf 40; Bordeaux-lead arsenate) gave 3-1 per cent. scabby and 1-3
per cent. wormy.

Considering the results of the pear scab control as a whole,
dusting and spraying were almost equally effective, but further
tests are necessary. Foliage sprayed with lime-sulphur was con-
siderably damaged, especially after the ‘calyx’ application, while
that dusted was uninjured. The value of the pre-pinking spraying
was definitely proved.

Brown rot [Sclerotinia cinerea] has been the cause of excessive
loss of peaches and plums in recent years, apparently healthy fruit
decaying before shipment or in transit. This has led to fruit being
put on the market in an immature state, resulting in reduced sales
and injury to commercial interests. Experiments were therefore
undertaken in 1920 and 1921 to develop a satisfactory method of
improving the keeping qualities of the fruit by control of brown
rot.

In the first experiment, the sprayed trees were treated three
times with lime-sulphur (13-50) combined with lead-arsenate (14 Ib.
in 50 galls.) and once with lime-sulphur alone, while the dusted
trees were treated four times with sulphur-arsenate dust (90-10)
and twice with sulphur alone. The results both from spraying
and dusting up to the time the fruit was picked were very satis-

73

factory, while a late application of sulphur dust reduced the
development of rot after picking.

In the second experiment, sulphur-hydrated lime-arsenate dust
(first dusting 75-15-10, second dusting 85-15-0) gave at the time
of picking 0-7 per cent. of peach scab and 3 per cent. of brown rot,
while the control gave 18 and 13 per cent. respectively.

A series of experiments was carried out on plums and peaches
with the single purpose of finding whether sulphur-hydrated lime
dust (85-15 or 90-10) would retard the development of brown rot
after picking. The dusted trees invariably gave a lower percentage
of brown rot (5 to 35) than the controls (30 to 100). The dusting
was done three days to one month before the picking, and the
results were taken four to twelve days after picking.

The late application of sulphur dust therefore greatly improves
the keeping qualities of the fruit, but such treatment should only
be considered as supplementary to the regular summer schedule
and not as a substitute for it.

Experiments were also carried out in 1920 and 1921 to test the
efficiency of lime-sulphur, Bordeaux, sulphur dust, and dehydrated
copper sulphate dust in controlling leaf spot of cherry [Coccomyces
hiemalis| on the varieties English Morello and Montmorency. On the
latter the results were inconclusive owing to the slightness of attack.
On the former, however, in 1920, Bordeaux mixture (4-6 hydrated
lime—50) gave good control, but caused serious injury to the foliage ;
lime-sulphur (14-50) ranked second, and the two dusts, sulphur-
arsenate (90-10) and lime-copper-arsenate (75-15-10) a little lower
still. In 1921 the control by all materials [lime-sulphur (13-50),
Bordeaux (4-7 hydrated lime-50), sulphur-arsenate-lime dust (80-
10-10), and lime-copper-arsenate dust (70-20-10) with 10 per cent.
talc] was almost perfect, but Bordeaux resulted in the fruit being
undersized, a similar trouble having recently been reported from
the North-West.

Comparative tests of dry and liquid lime-sulphur for the control
of apple scab showed, as in previous years, that the latter gave the
better results.

Following an experiment made in 1919, another trial was made
to control peach leaf curl [Hxoascus deformans] by dry spraying,
but satisfactory control was not obtained with soluble sulphur or
Bordeaux dusts.

Coons (G. H.). Copper dust treatment for stinking smut.—
Quarterly Bull. Michigan Agric. Exper. Stat., v, 1, pp. 8-11,
1 fig., 1922.

Stinking smut or bunt of wheat [7 %lletia tritici] reduces the
Michigan crop by at least 5 per cent. annually. In the autumn of
1921 experiments were carried out on very heavily smutted wheat
to determine the comparative efficiency of various methods of con-
trol. The following results were obtained: ‘dry ’ formaldehyde
[see this Review, i, p. 436], 3 per cent. of infection; sprinkling with
1 pint commercial solution of formaldehyde in 40 galls. of water,
O per cent.; immersing in the same solution and skimming off the
unbroken bunt balls, 0-5 per cent. ; copper carbonate dust, 2 oz. per

74

bushel, 1-4 per cent.; dehydrated copper sulphate and lime dust,
2 oz. per bushel, 4 per cent.; untreated, 51 per cent.

The formaldehyde treatments gave satisfactory control, but some-
what reduced the stand. The copper carbonate and copper sulphate-
lime dusts would probably effect complete control on ordinary-grain
fit for seed purposes. The copper dusts had no adverse effects on
germination, and their use on a large scale (for wheat only) is
recommended.

BovurILLaRD (R.). Emploi du lysol contre la carie. [Use of lysol
against bunt.|—Journ. Agric. Prat., \xxxvi, p. 2038, 1922.

The writer states that he has obtained excellent control of bunt
by the disinfection of seed wheat with 5 per cent. lysol (200 gm.
lysol and 4 litres of water per hectolitre of seed). Not a trace of
the disease has been observed during the four years over which the
tests have extended. Compared with copper sulphate, lysol appears
very slightly to retard germination (one to three days), but no
difference is noticeable at maturity. The retail price of lysol is
slightly higher than that of copper sulphate, but the former is in
several respects more convenient. Seed steeped in lysol in the
morning can be sown the same evening, and the preparation of the
mixture is very simple. Seed which has been thoroughly treated
by lysol assumes a light walnut tint. The treatment is applied by
sprinkling the grain, which should be well shovelled over during
the process.

KiLaApHaak (P. J.) & Barrett (H. H.). A preliminary notice of
genetical studies of resistance to mildew in Oenothera,—
Amer. Journ. of Bot., ix, 8, pp. 446-458, 1922.

Oenotheras grown for experimental purposes showed that nothing
is more characteristic of the various elementary species and hybrids.
than the great difference they exhibit in susceptibility to mildew
(Erysiphe polygoni). Such material therefore offered an excellent
opportunity for an investigation of the inheritance of disease
resistance, part of the results of which are given in this paper.

General observation indicated that susceptible species when
crossed reciprocally with immune ones gave only one immune cross.
It was not possible to get immune. hybrids by crossing susceptible
parents, while in the case of crosses between immune strains, both
reciprocals might be immune, or one of them immune and the other
susceptible.

In earlier papers the hypothesis of heterogametism has been
formulated (Bartlett, Amer. Nat., 50, pp. 5138-529, 1916, and Cobb.
and Bartlett, Journ. Wash. Acad. Sc., 9, pp. 462-483, 1919)
according to which each species of Oenotheru is supposed to produce
two types of gametes called a and B gametes. The former are
generally the female ones and the latter the male, but in a few
exceptions the pistil may transmit the 8 gametes and the pollen
the a, in which case instead of a normal hybrid of a 8 combination,
usually similar in character to one of its parents, a metaclinic
hybrid 6 a is produced, which plant resembles the reciprocal cross.

The hypothesis which is suggested to account for immunity is as
follows. The immune strains. carry a factor I for immunity, the

— he

75

susceptible strains a factor i which denotes absence of immunity or
presence of a factor for susceptibility. If in an immune strain only
one type of gamete bears the I factor, and if only a8 combinations
are viable, then such a strain will breed true for immunity but will
give a susceptible hybrid, one way or the other, when reciprocally
crossed with a susceptible strain. I is considered to be the dominant
factor and may be an attribute of the a gamete or the ® gamete.

On the basis of the above hypothesis the authors have worked
out the zygotic composition of the five strains of Oenothera selected
for the experiments as follows :—

Oenothera pratincola (‘ Lexington C’) aii, susceptible.

‘Oe. biennis Chicago’ aiPi, susceptible.
Oe. iivississippiensis aii, susceptible.
Oe. pratincola hyb. immunis aiPI, immune.
Oe. cinerescens aI fi, immune.

Ersiphe polygont appeared to show indications of the existence
of ‘biologic strains’, as conidia from the pea did not produce
infection on Oenothera whilst conidia from Oenothera did so. No
morphological differences could be correlated with this behaviour.

In planning the experiments the immune strains were freely
tested as regards immunity, by growing them among highly sus-
ceptible ones. The objection that-strains of 4. polygoni might
exist elsewhere which would infect the so-called immune strains of
Oenothera is hardly revelant, sce the authors are concerned not
with the production of disease-free plants, but rather with the fact
that immunity to certain strains of LZ. polygon: exists, and that
such immunity acts as a dominant unit factor in heredity.

Details are given of numerous crosses made with the five strains
of Oenothera mentioned above, each strain being selfed and also
crossed with the four remaining ones. Three examples may be
cited as illustrative of the crosses made, the pistillate parent being
named first in each case.

(1) Oe. mississippiensis (susceptible) x Oe. cinerescens (immune)
gave all susceptible progeny of the constitution aifi with the
exception of one metaclinic plant which was immune. In the
reciprocal cross, the progeny, «Ii, were all immune except in
the case of one metaclinic plant of the type Oe. mississippiensis,
which was susceptible.

(2) Oe. mississippiensis (susceptible) x Oe. pratincola hyb. im-
muivis (immune) gave all immune progeny (aif I) of the nvississip-
piensis type. From the reciprocal cross, all the progeny (aif i)
except one, a mutation, were matroclinic and resembled Oe. pratin-
colu except in susceptibility to mildew.

(3) Oe. cinerescens (immune) x Ve. pratincoia hyb. vmmunis
(immune) gave all immune progeny (aIfTI), and the reciprocal
cross gave all susceptible plants (ai i).

In every one of the cases analyzed in this way the reaction of
the hybrid to mildew conformed exactly to expectations, according
to the formulation above.

On account of the peculiar type of heterogametism in Oenothera,
immunity due to a single factor must breed as true as that due to
a factor pair.

The F, generation obtained by self pollination of the hybrids

76

showed the same characteristics as regards susceptibility or im-
munity as the F, generation, a result which should have been
expected on the basis of the authors’ hypotheses of heterogametism
and immunity.

In the case of metaclinic hybrids from immune and susceptible
parents, the immunity factor combination which would insure
susceptibility or immunity in one particular type seems not to
insure the same effect in another type. Further investigations
have been started on this matter, but so far as the normal hybrids
are concerned the results are all consistent.

Bonar (L.). An albino mutation of the Dematiaceous fungus
Brachysporium trifolii.—Science, N.S. lvi, pp. 226-227, 1922.

Cultures of B. trifolii were started from a single spore in October
1919, and have been continued as a pure strain ever since. The
fungus is normally of the Dematiaceous type, with dark brown
hyphae forming a dense, black mat in and on the culture medium.
In one of a series of cultures made in November 1921, a sector of
growth appeared which completely lacked the usual dark brown
colour, although the mycelium and conidia were identical in all
other respects with the normal growth.

Pure cultures of the albino- material were carried on through
sixteen consecutive non-sexual generations without any variation
in the appearance or nature of the strain. The mycelium in mass
is a true albino or may at times assume a pale flesh colour. Every
modification in-conditions thought of was used in these cultures for
the two and a half years they have been maintained, and there has
been an entire absence of any sexual process either in the normal
or albino strains. The phenomenon of albino mutation must there-
fore be referred to some sudden change, hitherto inexplicable, in the
mycelium or conidia of the normal strain.

LAGERBERG (‘T.). Cordiceps militaris (L.) Link i Sverige. [Cordi-
ceps militaris (L.) Link in Sweden.|—Svensk Botan. Tidskr.,
Xvi, 2, pp. 285-290, 2 figs., 1922.

The author found Cordiceps militaris in 1920 and 1921 on larvae
of Smerinthus populi, Cymatophora flavicormis, and C. duplaris.
The locality was a ravine in South Dalarne, the trees in which were
mainly Populus tremula and Saliz. The soil humus was markedly
alkaline and the ground was covered with a layer of damp, rotting
foliage. Further ecological particulars of the locality are given,
together with a list of the mosses, ferns, grasses, &c., represented
there.

According to Bilow (Svampar, 3rd Ed., p. 253, 1919), C. militaris
is extremely rare in Sweden, but may be found year after year in
the same place. The fungus is represented by only a very few
specimens in Swedish collections. A brief description of its macro-
scopic characters and life-history is given.

JOHNSON (J.). The relation of air temperature to the mosaic
disease of Potatoes and other plants.—Phytopath., xii, 9,
pp. 438-440, 1 fig., 1922.

Following his previous work on the temperature relations of the

77

mosaic disease of tobacco [see this Review, i, p. 243], the author
gives the results of similar experiments which he has conducted
with mosaic diseases of potatoes, tomatoes, soy-beans, pea-beans,
and clover.

Young potato plants showing symptoms of mosaic were placed in
air-control chambers held at temperatures ranging between 6° and
36° C. for one to three weeks, parts of the individual tubers in each
series being represented in each chamber. The effect of temperature
was gauged by the intensity of the symptoms of the mosaic or the
rate of ‘recovery’ from the disease.

The results have shown that temperatures as low as 6° C. seem-
ingly do not inhibit the disease, which persists at temperatures
where the potato makes little or no growth. Taking the growth
of the host into consideration, the optimum temperature for the
disease lies between 14° and 18°C. Above 20°C. symptoms dis-
. appear, but a temperature of 24° to 25°C. is necessary to cause
them to disappear in one to two weeks (old leaves taking longer
to ‘recover’ than young ones), so that this temperature may be
regarded as the maximum temperature for mosaic manifestation in
the potato.

The expectation that exposure to high temperatures would
destroy the mosaic virus has not been realized so far, although the
effect of exposure for 10 days at 36° C., while not entirely destroying
the virus, indicated that longer treatment may be effective without
destroying the germination of the tuber.

Certain other mosaic diseases, worked with in less detail, have
responded to temperature, some, like tomato mosaic (inoculated
with tobacco virus), falling in the high temperature class with
tobacco, others, like clover mosaic, in the low temperature class,
and others being intermediate. Soy-bean mosaic is inhibited at
temperatures of from 26° to 28°C., but the pea-bean mosaic can
apparently persist at a considerably higher temperature.

NELSON (R.). Transference of the Bean mosaic virus by Macro-
siphum solanifolii.— Science, N.S. lvi, pp. 342-344, 1922.

The author describes a series of observations and experiments
which are regarded as definitely proving that Macrosiphum solani-
foliz is concerned in the transmission of mosaic disease of beans
(Phaseolus vulgaris). This is stated to be the first experimental
proof of the transmission of this mosaic by insects. The varieties
affected were Long White, Golden Wax, Brittle Wax, and Green
Pod Stringless.

MELIN (E.). Untersuchungen itiber die Larix-Mykorrhiza. I. Syn-
these der Mykorrhiza in Reinkultur. [Investigations of the
Larix mycorrhiza. I. Synthesis of the mycorrhiza in pure
culture, |—Svensk Bot. Tidskr., xvi, 2, pp. 161-195, 13 figs.,
1922.

This is a full account of the author's successful syntheses of
certain coniferous mycorrhiza, especially that of Lariz europaea,
of which a preliminary statement has already been noticed [see this
Review, i, p. 442}.

A description is given of the characters of larch mycorrhiza and

78

the constant association of Boletus elegans with the larch is noted.
The methods of growing both symbionts in pure culture are
described at length and a full account is given of the effects of
bringing together the fungus and larch roots in pure: cultures.
The mycorrhiza thus formed by synthesis resembled the natural
mycorrhiza, and enabled the author to study the different stages
of mycorrhiza formation in some detail.

In similar attempts to synthesize larch mycorrhiza, using as the
fungus symbiont Mycelium radicis syl vestris a, B, and y [see this
Review, i, p. 122], only those with the 8 form gave typical mycor-
rhiza, which, however, diftered from those formed with B. elegans
in certain morphological characters. The a and y forms appeared
to act in a more parasitic manner than B. elegans, the y form
producing no true mycorrhiza. M.r. abietis formed no mycorrhiza
on the larch, which it attacked parasitically.

Boletus elegans was next tried on Pinus sylvestris and Picea abies
without effect, and the author concludes that the association of this
fungus with the larch is of an obligate nature. The relationship is
believed to be one of mutual symbiosis, each giving support of some
sort to the other.

Direct attempts to isolate the fungus from naturally formed larch
mycorrhiza failed, and even those produced synthetically gave no
fungous growth when the usual methods of isolation were tried.

McLuckie£ (J.). Studies in symbiosis. I. The mycorrhiza of
Dipodium punctatum R. Br.—Proc. Linn. Soc. New South
Wales, xlvii, 3, pp. 2938-310, 26 figs., 1922.

The cortex of the root of Dipodium punctatwm, a holosapro-
phytic orchid growing in the humus under Eucalypts in New South
Wales, contains an endophytic fungus which forms close coils in
the cells, especially in the vicinity of the nucleus. The fungus
occurs in the soil surrounding the root in the form of numerous,
branching, fine hyphae, many of which form a close tangle on the
surface of the root. From this tangle, hyphae penetrate the cortex
through the passage cells of the exodermis, branching freely and
infecting numerous cells within the exodermis, but not entering the
raphide cells or the meristematic zone of the root. In newly-in-
fected cells the hyphae are very slender, but they increase in thick-
ness after they have been within the cell for some time, and become
filled with dense, deeply staining, granular protoplasm with few
vacuoles. No vesicles are formed. The starch grains gradually
disappear from the cells after infection. In certain cells occupied
by the fungus for some time, the highly nourished hyphae begin to
disorganize, losing their individuality and forming a deeply staining
mass in the centre of the hyphal tangle. The nucleus of the in-
fected cell at the same time increases to twice or three times its
normal size, the nucleolus also enlarging. The chromatin stains
more deeply and appears more abundant, the whole condition being
suggestive of a high state of nutrition. The final appearance of the
fungus is an irregular mass of indefinite structure, but apparently
composed largely of proteids. Small droplets of a yellowish, highly
refractive substance were in some cases present in the host cells
at this stage. The gradual destruction of the fungus appears to

79

be the result of its digestion by the cytoplasm of the host cells.
The latter process is particularly marked immediately before and
during the development of the flowering shoot, when an extra
supply of proteid is evidently necessary. After digestion the cyto-
plasm of the host cells appears quite normal, and starch reappears
during the process, though in smaller quantities than before.

The penetration of the hyphae from cell to cell, and from the
soil into the root, is probably the result of a chemotropie stimulus
due to the presence in the host cells of a nutritive substance, pro-
bably sugar. The greater concentration of this substance round
the nucleus would explain the growth of the hyphae in that direc-
tion. The protoplasm or proteid of the fungal hyphae increases at
the expense of the starch which disappears from the infected host-
cells; hence the carbohydrates of the latter appear to be used in
the synthesis of nitrogenous food in the mycelium, which at this
stage must be regarded as parasitic. The nitrogen for this process
is probably derived from the soil through the hyphae connecting
the endophytic mycelium with that on the surface of the root. In
the next stage the substance of the fungus is taken up by the host
plant by a process of digestion.

In Dipodiwm the higher plant appears to derive most benefit
from the association. The fungal hyphae forming the mycorrhiza
are indispensable to the host, which is devoid of chlorophyll, and
therefore incapable of photosynthesis. Such starch as it contains
is probably the result of the presence of the endophyte, which
appears to be never exterminated, but to be always active in some
part or other of the root. The higher plant is further without
root-hairs and, therefore, dependent on the fungus for its supplies
of water, ash constituents, carbonaceous substances, and nitrogen;
in fact, it appears that all its requirements are supplied directly or
indirectly by the fungus. Thus the higher plant may be regarded
as being, on balance, parasitic upon the endophyte.

SUNDARARAMAN (S.). The Coconut-bleeding disease.— Agric. Res.
Inst. Pusa, Bull. 127, 8 pp., 6 pl. (1 col.), 1922.

The first symptom of the coco-nut bleeding disease, which is
widely distributed in the Madras Presidency, is the exudation of
a reddish-brown fluid from cracks on the surface of the stem. This
fluid turns black as it dries. The tissue below the bleeding portion
is decayed and yellow, at first in localized patches, then extending
and involving much of the interior of the stem. At an- advanced
stage of the disease, the crown dwindles and the palm ceases to bear
nuts and finally dies. Young palms are the most severely affected,
especially when the base is attacked. The inner, soft tissue rots,
and a cavity is formed in the centre of the stem. Here a thin,
yellowish fluid accumulates and gushes out when the cavity is
incised. If the decay extends downwards the tree becomes hollowed
out, no external symptoms of disease being visible. When this
oceurs the whole palm should be cut out and burnt as treatment is
impossible. The disease is caused by a fungus, Thielaviopsis paru-
doxa, a brief historical and descriptive account of which is given.
Inoculations with mycelium from glucose agar cultures were carried
out on seedling plants grown in pots. The results indicated that

80

the fungus infects the stem through a wound or erack, and also
that it cannot attack uninjured leaves or petioles.

The most effective remedy in cases of localized infection is to
excise the diseased parts, together with about an inch of the sur-
rounding healthy tissue. ‘This operation should be followed by
the drying of the cut surface with fire, and the application of
hot tar to the wound. This treatment has proved very successful
in a case under the writer’s observation, in which one hundred trees
were completely cured. It is important to remember that the
external symptoms do not always indicate the extent of the internal
decay, the latter often being found at a considerable distance from
the parts visibly affected on the exterior of the stem,

GARNER (W. W.), McMurtrey (J. E.), & Moss (E. G.). Sand drown,
a chlorosis of Tobacco and other plants resulting from mag-
nesium deficiency.— Science, N.S., lvi, pp. 341-842, 1922.

Investigations have been carried out by the Bureau of Plant
Industry, in co-operation with the North Carolina Department of
Agriculture, on a chlorosis of tobacco popularly known as ‘ sand
drown’. The disease, which occurs in an aggravated form on
sandy fields after heavy rainfall, has been found to be due to an
insufficient supply of magnesium in the soil or fertilizer. The
ratio between the quantities of sulphur (sulphate) and magnesium
contained in the fertilizer is also important, the symptoms of
magnesium deficiency being intensified by an increase in the
quantity of sulphur applied to the soil.

The chlorosis usually begins at the tip and along the outer
margins of the older leaves, advancing towards the leaf base and
extending progressively to the upper leaves of the plant. Some-
times, however, large areas of the leaf surface may already be
involved when the symptoms first become noticeable. The veins
and midrib of the leaf tend to retain their normal colour, but there
is more or less complete blanching of the lamina, both yellow and
green chlorophyll pigments being affected. In this respect, and in
the more gradual death of the affected tissues, ‘ sand drown’ differs
from the chlorosis due to potassium deficiency. Sandy and sandy
loam soils appear to be chietly affected, especially where the rainfall
is abundant.

The addition of sulphate or chloride of magnesium to the ferti-
lizer has always resulted in the control of the disease. Comparative
tests indicated that low grade sulphates and chlorides of potassium
containing large quantities of magnesium, such as kainit and
‘double manure salt’, prevent this chlorosis, while high grade
sulphates and chlorides of potassium intensify it. Dolomitie lime-
stone also prevents it, while comparatively pure calcite is ineffective.
Cotton seed meal, tobacco stalks and stems, and organic manures
also tend to reduce ‘sand drown’, as they all contain appreciable
quantities of magnesium, while other common sources of nitrogen
which are deficient in magnesium, e.g. nitrate of soda, dried blood,
and ammonium sulphate, favour its development. In pot cultures
this type of chlorosis is readily induced by omitting magnesium
from the nutrient solution, and may be cured by adding magnesium,
at any rate in the early stages. The constant addition of sulphur

81

to the goil from rain water during rainy seasons, and the -corre-
spondin® loss of magnesium by leaching, explain the greater
prevalence of the disease under such conditions.

Experiments have shown that maize is also liable to ‘sand
drown’, which probably affects a wide range of crops in light, sandy
soils. Probably less than 50 Ib. of magnesium per acre would
suffice to remedy the deficiency. These investigations indicate the
necessity for taking magnesium into account both in the general
problem of liming and in the composition of so-called complete
fertilizers.

Nopécourt (P.). Sur le mécanisme de l’action parasitaire du
Penicillium glaucum Link et du Mucor stolonifer Ehrb. [On
the mechanism of the parasitic action of Penicillium glauwcum
Link and Mucor stolonifer Ehrb.|—Comptes Rendus Acad. des
Sciences, elxxiv, 26, pp. 1720-1722, 192z.

The author’s experiments, a short description of which is given,
indicate that the destructive action of Penicilliwm glaucum and
Mucor stolonifer on fruits is due to enzymes secreted by these
fungi. The juice expressed from fruits rotted by them was found
to have a pronounced cytolytic and plasmolytic action on thick
slabs of different fruits, pieces of carrot, Jerusalem artichoke, onion
bulbs, broad bean stalks, &c., immersed in it. By heating at about
60° C. for 15 minutes the juice loses this destructive power, which
is furthermore temporarily inhibited at temperatures near the
freezing point. The active substances can be extracted from the
juice by strong alcohol, and water solutions of the precipitate thus
obtained act in the same way as the juice itself. These enzymes,
which the author calls ‘ fungal toxins ’, only act in an acid medium ;
after adding bicarbonate of soda to the active juice, the latter can
no longer destroy plant tissues immersed in it. An attempt to
obtain the toxins from carrot broth in which both fungi were culti-
vated was unsuccessful, even though there was an abundant growth
of mycelium in the medium, but the liquid obtained by macerating
the mycelium of JV. stolonifer for a few days in distilled water
possessed the power of disorganizing plant tissue. The toxins
secreted both by P. glaucwm and M. stolonifer disorganize tissues
of plants which the fungi themselves cannot attack; the author
concludes therefore that the immunity of such plants is not due to
the resistance of their tissues to the substances secreted by the
fungi, but to some other causes which he is trying to determine.

WILLAMAN (J. J.) & Davison (F. R.). Biochemistry of plant
diseases. IV. Proximate analysis of Plums rotted by Sclero-
tinia cinerea.— Botan. Gaz., |xxiv, 1, pp. 104-109, 2 figs., 1922.

Proximate analyses of several resistant and non-resistant varieties
of plums rotted by Sclerotinia cinerea showed that the rotted tissue
consistently contained a higher percentage of ash, calcium oxide,
nitrogen, and ether extract than the tissue of sound plums; the
authors believe this to be probably due to a loss of dry matter
through respiration, which previous work has shown to be higher
in infected than in sound plums. Crude fibre contents were found
to be markedly higher in the resistant than in the susceptible

82

varieties. while the percentage of all other constituents was lower
in the former, but not sufficiently so to limit the nutrition of the
invading organism. It appears quite probable that the quality and
quantity of cellulose material are important factors in resistance.
lt was noted that as the ripening of the plums proceeded, there was
a decrease in the ash, nitrogen, and calcium content, due probably
to storage of carbohydrates and acids.

Youne (H.C.) & Bennett (C. W.). Growth of some parasitic fungi
in synthetic culture media.—Amer. Journ. of Bot., ix, 8,
pp. 459-469, 4 text figs., 1922.

The authors have carried out an investigation of the importance
of the various elements in synthetic culture media for fungi, aid
the best concentrations in which to use them.

A review of previous work on the food requirements of fungi is
given, together with formulae by Raulin, Mayer, Pfeffer, Richards,
Currie, Uschinsky, Czapek, and Coons. In general all the solutions
yet devised depend upon whether the investigator considered the
presence or absence of the inorganic constituents important for the
growth of the fungus, and do not appear to have been founded on
accurate study. The roles of calcium, iron, and zine seem to have
especially caused discussion. Molisch considered calcium unneces-
sary for normal growth, and although this fact is based on little
experimental data it has been generally accepted. Currie concluded
that iron has no effect on Aspergil/us niger. Others, however, have
found both iron and calcium beneficial although not essential.
Steimburg has more recently shown that zinc has a very decided
stimulative effect.

In determining the réle of the so-called essential inorganic
elements along with that of calcium and zinc, Richards’ solution
(potassium nitrate 1 gm., potassium acid phosphate (monobasic)
0-5 gm., magnesium sulphate 0-25 gm., ferric chloride a trace,
saccharose 3-43 gm., and water 100 cc. Reaction P, 4-2) was used
as a standard and as a basis for the deviations, the inorganic con-
stituents being replaced by non-essentials and the sucrose by
different sugars. The possible importance of impurities was recog-
nized and only selected glass and specially prepared chemicals were
used. Cultures of Fusarium oxysporum, Aspergillus niger, and
Rhizopus nigricans were made in flasks containing the various
solutions and the dry weight of mycelium taken after sixteen days.
The results indicate that calcium exerts a stimulative action on
growth, and although the exact manner in which this is effected is
problematical the rdle of calcium in counteracting acidity probably
plays an important part in the process. To make sure that the
increased weight was due to fungous growth and not to calcium
oxalate, the mycelium was treated with alcohol and 30 per cent.
hydrochloric acid. Zine sulphate stimulated the growth of A. niger
but not of F. orysporwm or R. nigricans. The quantity of acid
produced by A. niger and R. nigricans is proportional to the
amount of fungous material produced: with available carbon,
growth continues until stopped by hydrogen-ion concentration.
The acidity of the culture solution in which F. oxysporum was
grown increased to a maximum of P, 3-6 and then diminished,

83

alkalinity developing until all the organic compounds were broken
up and a Py value of 8-4 was reached.

A further experiment on the effect of calcium and zinc on the
growth of eighteen parasitic organisms showed that calcium is
generally beneficial, though in the case of four organisms it retarded
erowth. Rhizoctonia solani grew only when calcium was present.
Fusarium radicicola was pink in solutions containing calcium and
colourless in potassium solutions. Zine sulphate gave slightly
beneficial effects with only two organisms.

It would seem that the salt requirements for an optimum
synthetic solution should contain nitrogen, phosphorus, sulphur,
potassium, calcium, and magnesium. There is no evidence of the
correct proportions in which these inorganic elements should be
used, but since the salt requirements for fungi are probably the
same as for higher plants, two triplicate series of twenty-one cultures
were made on the method used by the National Research Council
| United States] for work in the study of the nutrition of higher
plants. Potassium acid phosphate (monobasic), calcium nitrate, and
magnesium sulphate were used in one series. The salts varied in
the different solutions by increments of one-eighth and had an
osmotic concentration of 3-5 atmospheres. Sucrose was added in
equal amounts of 3-43 gm. per 100 cc. of the solution, thereby
giving the culture solutions a total osmotic pressure of 4-5 atmo-
spheres. Potassium nitrate, calcium acid phosphate, and magnesium
sulphate were similarly used in the other series. Fusariwin oxy-
sporum, Macrosporium sarcinaeforme, and Phoma apiicola were the
fungi used, and dry weights were determined after sixteen days
incubation. The results of this experiment show clearly that a
proper balance of the inorganic constituents in the solution is
essential for maximum growth, and that this balance can be readily
obtained by the use of the triangular system of the National
Research Council. By this system the mineral requirements of any
particular fungus can be quickly and accurately ascertained, and by
selecting the sugar most readily used, a favourable culture solution
can be made.

Poue Evans (I. B. & Mary). Rise in temperature of living plant
tissue when infected by a parasitic fungus.— Vatu, cx,
2762, pp. 480-481, 1922.

In investigating the etfects of inoculating oranges and grapefruit
with Penicillium digitatum the authors found that a very definite
rise of temperature took place in the infected living tissues, while
the temperature was not observed to rise when the host tissue was
killed prior to inoculation. To what extent direct reaction of the
host is responsible for this rise of temperature is still to be deter-
mined, and also whether the phenomenon is a general one, occurring
in all cases of attack by parasitic fungi on living plant tissue.

Testing of new varieties of the Potato for immunity from wart
disease.— Scottish Journ. of Agric., v, 3, pp. 306-311, 1922.
New potato varieties sent in for trial are tested for immunity
from wart disease during at least two years at the Philipstoun
station of the Scottish Board of Agriculture, as a susceptible variety

84

might conceivabiy escape detection in a dry season unfavourable
for the development of the disease. A certificate of immunity is
given to the varieties which satisfactorily stand the test. In the
second year of trial the varieties are grouped together in the field
according to certain standard characteristics of the tubers and
haulms, of which the colour of the sprouts grown in diffuse light
and the date of maturity of the tubers form the two main bases of
classification: both features are fairly constant and the Jatter is
of the greatest importance to the growers.

The tests completed in 1921 comprised 130 varieties, including
some eighty from the United States and twenty-two from Germany ;
in addition, a large number of single tubers and seedlings were
submitted for a preliminary test. Among the American varieties,
only four of the Up-to-Date type were of outstanding merit and
these were non-immune from wart disease; eighteen named sorts
and three seedlings proved to be immune. These eighteen named
varieties comprise only ten types as follows:—lIrish Cobbler (4),
Early Harvest, Ehnola, Perfect Peachblow, Early Manistee, Green
Mountain (6), Netted Gem, Keeper, Northern King, and McCormick.
It is noted that Irish Cobbler and Keeper are indistinguishable from
the British varieties America and Sutton’s Flourball respectively ;
these sorts were first put on the market in the United States and
the stocks have been subsequently sent over to England. The non-
immune varieties included representatives of the Rural New York,
Early Rose, and Beauty of Hebron types, and also of the British
Up-to-Date type. Of the German varieties tested only four proved
to be immune, while none appeared to be as good as the British
standard types. ;

A very large and representative collection of British varieties,
immune and non-immune, was sent to the United States in 1920.
According to the report of 192! the following sorts proved to be
free from leaf-roll, mosaic, streak, and diseases of unknown origin:
Ally, May Queen, Great Scot, Rector, Climax, Provost, and Duchess,
while the varieties Epicure, Dargill Early, Majestic, and Rhoderick
Dhu had only 5 per cent. of their numbers affected. The amount
of disease in Tinwald Perfection, Golden Wonder, Resistant Snow-
drop, Eclipse, Langworthy, Arran Victory, Irish Queen, Templar,
King Edward, Lochar, Witchhill, Mauve Queen, Bishop, and Immune
Ashleaf was over 50 per cent. Of a similar consignment sent to
Germany, many were destroyed by frost and only Great Scot was
regarded with favour.

Wart disease of Potatoes: immunity trials.—(Gurd. Chion., |xxii,
p. 229, 1922.

The results of the tests for immunity from wart disease demon-
strated on 28th September 1922, by the Scottish Board of Agriculture
at Philipstoun, West Lothian, showed that selfed immune varieties of
potatoes produced a large number of immune seedlings. In many
respects the latter reproduced their parents’ characteristics; some,
such as those from Ally, Abundance, and Templar, were indistin-
guishable from the parents and showed a high percentage of immune
individuals. The result of crossing an immune and a susceptible
variety (Flourball x President), showed about 40 per cent. of immune

a ee ee ee

es

85

individuals after two years, whereas the crossing of two immunes
(Majestic x Flourball) gave 70 to 80 per cent. of immunity. Seed-
lings of Up-to-Date x Majestic also showed a fair proportion of
immune types.

WAKSMAN (S. A.). The influence of soil reaction upon the growth
of Actinomycetes causing Potato scab.—Soi/ Science, xiv, |,
pp. 61-79, 1922.

The results of a series of experiments showed that the limiting
acid reaction for the growth of Actinomyces scabies in culture solu-
tions, properly buffered, and in sterile soil, varies with the strain.
The determinations of the growth in liquid cultures were made by
filtering off and weighing the fungus, and in soil cultures by
measuring the production of ammonia. In some of the soil series
the amount of Actinomyces was determined by plating and counting
the colonies.

In the majority of cases, the limiting acid reaction is about
P,, 5-0 to 5-2; some strains even grow at P,, 4-8, while others begin
to develop only at P, 5-3 to 5-6. These results, in the main, bear
out those of Gillespie (Phytopath., viii, 6, p. 257; Soil Science, iv, 4.
p- 313; and v, 3, p. 219). The optimum hydrogen-ion concentration
in the soil cultures was found to be from Py 5:8 to 7-7, while the
limit on the alkaline side was Py 8-8. The alkaline limit is there-
fore too high for arable cultivation, but the acid limit will allow
good crops of potatoes to be grown. The saprophytic soil Actino-
myces appear to be more acid resistant than the strains of
A. scabies. By the use of the proper amount of sulphur inoculated
with Thiobacillus thiooxidans, an acid reaction can be obtained
which will control common potato scab. This is equivalent to
making the soil acid by means of sulphuric acid, since the sulphur
is oxidized to H,SO, by the action of the bacillus. In soils that are
already of an acid nature, the use of green manures may suffice to
control scab owing to the formation of organic acids during their
decomposition.

It is admitted that the term Actinomyces scabies includes a group
of pathogenic forms, but the various strains examined by the writer
appear to be covered by the limitations given above.

JeNNISON (H. M.), Potato blackleg, with special reference to the
etiological agent.—Abs. in Phytopuath., xii, 9, p. 444, 1922.

Continuing his investigations of Bacillus atrosepticus van Hall
[see this Review, 1, p. 82], the author presents the index-
number 5312-32120-2110 in lieu of a fuller (revised) description
of this organism. The bacillus develops acid and gas in the
presence of a number of saccharides. Gas production is weak
initially, but is capable of intensification by cultivation in sugars
which the organism can utilize. It secretes invertase, lactase, and
maltase, and quantitative determinations showed that it cannot
hydrolyse potato starch or dextrin.

Ricuarps (b. L.). Corticium vagum as a factor in Potato produc-
tion,— Abs. in Phytoputh., xii, 9, p. 444, 1922.
In a series of pure culture experiments, several strains of C.

86

vagum were found to produce severe and characteristic cankers on
all underground parts of the potato, young plants being attacked
most vigorously, and growing points being especially susceptible.

In extensive field experiments the fungus, under favourable con-
ditions, seriously reduced the number and size of the tubers,
decreased the number of stems per hill, and greatly weakened the
surviving ones which were usually undersized and died early.
Yields from 500 diseased hills and 500 disease-free hills, grown
under comparable conditions, showed that inoculation of the soil
with the Rhizoctonia stage of C. vagum reduced the crop to 50 per
cent. of that obtained from treated seed. Under natural conditions,
soil temperature proved to be the most important factor in deter-
mining the loss.

RaEpDER (J. M.) & HuNGErrorD (C. W.). The effect of presprinkling
with water upon the efficiency of certain Potato seed treat-
ments for the control of Rhizoctonia.—Abs. in Phytopath.,
xii, 9, p. 447, 1922. |

Preliminary laboratory tests have shown that disinfective treat-
ments for seed potatoes are rendered more efficient by presprinkling
with water. Potatoes sprinkled and covered for 24 hours, then
treated with formaldehyde (1 in 120) at 50°C. for 3 minutes or
55° C. for 1 minute, or covered for 48 hours and treated with for-
maldehyde (1 in 120) at 50°C. for 2 minutes, gave clean seed, but
cultures from seed similarly treated, except that they were not pre-
sprinkled, showed that the control was not absolute.

Sprinkling with water and covering 24 to 48 hours before treat-
ment with mercuric chloride was advantageous, but in no case was
the control absolute.

Mince (E.). Sur une maladie de la Pomme de terre observée au
Maroc. [On a Potato disease observed in Morocco.]—Bull.
Soc. Path. Vég. de France, ix, 2, pp. 109-112, 1922.

The author believes that a disease of potatoes observed by him
at Rabat (Morocco) in 1921 has not previously been described.
Although a bacterial origin is suspected, his inoculation experiments
so far have given inconclusive results.

The symptoms visible on the aerial portion of the plant are very
characteristic. The progress of the disease is plainly basipetal. It
begins at the extremity of the branches. usually those at the top or
middle of the plant. The terminal leaflet after being covered with
brown patches resembling burns, blackens and dries up rapidly and
completely ; the petiole is immediately afterwards attacked at its
upper extremity and soon dries up, the diseased portion being at
first sharply detined from the lower part, which remains green and
healthy. The disease spreads progressively and pretty rapidly over
the whole of the branch, working toward the main stem and
destroying all the leaflets on the way. In a few days the whole of
the branch first attacked is completely withered and blackened and
other branches become involved. The main stems are invaded and
covered with elongated, blackish spots which originate from contact
with a diseased branch. The tubers are sometimes infected before
maturity, but they may show no symptoms whatever at harvest

87

time, and only become outwardly diseased some days or even weeks
after lifting. The disease is easily recognized on the surface of the
tuber by the presence of blackish-purple dots, at first rare, later
more and more numerous. Subsequently the zone underlying these
dots takes on a blackish-brown hue, which spreads progressively.
Finally, the affected parts undergo a soft rot from which, under
pressure, a fairly clear liquid exudes: the whole tuber rots rapidly,
and is rendered useless. Even where the symptoms are not visible
on tubers just dug up, the number and size of the latter are
frequently reduced, even more so than is the case with Phytophthora.

The trouble occurred again in the autumn crop, planted on the
4th October. At the beginning of December the varieties Italie
Blanche, Early Rose, and especially Saucisse and Mayette Hative,
were suffering from a rather mild attack, while Italie Rouge. Ricce,
La Quarantaine, and Express remained more or less immune.

The damage done by this disease is considerable, most of the
varieties cultivated in Morocco being affected in varying degree
throughout the growing season. é

BENNETT (J. P.) & BARTHOLOMEW (E. T.). Respiration of Potatoes
in relation to the occurrence of blackheart in storage.—Abs.
in Phytopath., xii, 9, p. 443, 1922.

The work of earlier investigators indicated that blackheart was
due to a disturbance of respirational processes dependent on a tem-
perature-time-oxygen relationship. This relationship appears to
be fairly definite. From 40° down to 5°C. the period of exposure
required to induce blackheart increased from 8 to 77 days. Below
35°C. blackheart did not occur until the oxygen was practically
exhausted : with increase of temperature above 30° C. an increasing
amount of oxygen remained when blackheart appeared. Injury
leading to the development of blackheart appears to be due to
anaerobic processes. At temperatures where oxygen exhaustion
precedes blackheart, the injury may appear in any part of the tuber;
at higher temperatures it usually occurs centrally.

GAUMANN (E.). Enkele opmerkingen omtrent de Lampongsche
Peperziekte. [Some observations on the Lampong Pepper
disease. ]|— Teysmannia, xxxiii, 7-8, pp. 289-293, 1 pl., 1922.

Although the premature death of pepper vines [Piper nigrum],
which has long been known as a serious disease in Sumatra and

West Java, is, according to Rutgers’ observations (M/eded. Inst. voor

Plantenziekten 18, 19, and 27), closely connected with defective or

unsuitable cultivation, cases have also occurred of the sudden

decline of apparently healthy vines in well cared for plantations.

The present paper deals with the writer's preliminary investigations

of the latter form of the disease. The material studied was from

an experimental plantation of the Phytopathological Institute at

Buitenzorg, started in 1915. It had received the most careful

attention, but by 1920 a number of vines had begun to die off, and

the disease has now attained serious dimensions.

The death of the vines was preceded by certain well-defined
symptoms. Transverse sections of branches which were already
losing their leaves revealed a brownish discoloration of a part or

88

the whole of the vascular bundles. Microscopic examination showed
that most of the discoloured vascular bundles were dead and filled
with a brown, gummy exudation. Hyphae or bacteria were not
present, but the dead vessels or adjacent cells sometimes contained
a granular deposit along the cell walls. This discoloration was
found almost from the top to the bottom of the branches, and
extended to the veins of the leaves. The nearer the top of the
branch or the tip of the leaf, the weaker was the discoloration until
a point was reached when it disappeared. Sections through the zone
just beyond the point of visible discoloration revealed masses of
bacteria in many of the vascular bundles and adjacent cells, more .
than one-third of the xylem being invaded. The author’s observa-
tions indicated that the premature death of the vines was always
accompanied by discoloration, vines from which the discoloration
was absent not tending to succumb before their time.

Experiments were conducted to ascertain whether the bacteria
were concerned in the causation of the disease. Young plants
raised from seed, and also young healthy vines, were inoculated
with cultures of the bacteria obtained from the vascular bundles,
while others were inoculated for control purposes with a common
saprophytic bacterium. After a week the vascular bundles of the
former group of plants exhibited the typical discoloration to a
height of 10 cm., those of the latter showing only a general dis-
coloration of the inoculation canal. At the end of about ten weeks,
two of the young plants and three of the vines, inoculated with the
material from the diseased vascular bundles, shed their leaves and
died. The results of these tests prove that the premature death of
pepper vines, preceded by discoloration of the vascular bundles, is
due to bacteria, the systematic position, life-history, distribution,
and control of which require further elucidation.

The following tentative explanation is advanced for the diseased
condition of pepper vines found in the affected areas of the Dutch
East Indies. In addition to the continuous decay of the plants in
neglected plantations, which is directly due to malnutrition, there
is a bacterial disease which probably attacks only the vascular
bundles. This disease, like the corresponding one of bananas [see
this Review, i, p. 223], may long remain latent, the decisive factor
in its activity being neglect of cultivation. The specific agent of
the disease, however, is a bacterium, or group of bacteria, parasitic
in the vascular bundles, the conditions of cultivation, &¢., being
only contributory factors. Care must be taken not to use the dis-
coloured vines as cuttings for planting out as they will presumably
transmit the disease, and the possibility of growing the plants from
seed should be considered.

Lee (H. A.) & Mepatia (M. G.). The season’s experiments on
Fiji disease, mosaic disease, and smut of Sugar-cane.—
Philipp. Agric. Rev., xiv, 4, pp. 402-412, 8 pl., 1922.

Field experiments carried out at Canlubang in 1921 on Fiji
disease, mosaic disease, and smut gave the following results. The
germination of setts from canes affected with Fiji disease was much
lower than that of setts from healthy stools, and those that
did germinate gave diseased plants in any type of soil. None of

89

these diseased plants yielded any cane whatever, while many died
at a very early age. The spread of infection from diseased to
healthy plants was very low (3:46 per cent.). Thus the losses from
Fiji disease may be largely attributed to the use of tops and setts
from infected stools.

The germination of setts from stools affected with mosaic disease —
was slightly lower than that of setts from healthy canes, and, as
already found in Java, Hawaii, and Porto Rico, they usually trans-
mitted the disease, often to 100 per cent. of the resulting plants,
irrespective of the type of soil. Under Canlubang conditions the
spread of the disease from affected to healthy plants appears to be
very restricted, but further experiments will be necessary to deter-
mine the exact importance of insect and other methods of aerial
transmission. A small proportion of the plants may outgrow the
disease to such an extent that the leaf symptoms are no longer
visible.

' The germination of setts from stools of the susceptible Uba cane
affected with smut [Usti/ago sacchari] was distinctly poorer than
that of cuttings from healthy canes, and the disease was transmitted
in a large proportion of cases. There was no yield of cane from
affected cuttings. The spread of the disease to healthy stools was
very slight (0-75 per cent.) in the six months during which the
experiment lasted. Setts from healthy cane soaked in the same
receptacle as smutted cuttings showed 8-38 per cent. of infection in
the same time.

The results of all these trials indicate that the use of healthy
cuttings for planting is essential if the plantations are to be main-
tained free from disease.

Lee (H. A.), WeLLes (C. G.), & MEDALLA (M.G.). Fiji disease of
Sugar-cane in the Philippines.—Philipp. Agric. Rev., xiv, 4,
pp- 413-417, 3 pl., 1922.

Fiji disease, which is now fairly widely distributed in the Philip-
pines and rapidly spreading from north to south, appears to have
been introduced on cane cuttings from Australia or some of the
other countries affected. Its presence in the Philippines was first
detected in 1919.

The symptome of the disease [see this Review, i, pp. 187 and 269]
are described. and illustrated by excellent photographs. It is stated
that entire loss of the crop has been observed, but that it is usually
restricted to 10 to 25 per cent. of the plants. Badilla cane appears
to be the least susceptible variety, and it is in other respects a
better cane than the Negros Purple variety now generally planted
in Negros.

RicHARDs (B.L.). Relation of rainfall to the late blight or Phoma
rot of the Sugar Beet.—Abs. in Phytopath., xii, 9, p. 443, 1922.
During 1921 a late blight of sugar beet became epidemic in
northern Utah and southern Idaho and caused severe damage, the
intensity of the attack varying from a fraction of 1 per cent. to
the total destruction of the crop.
The available evidence indicates that the trouble is possibly
identical with the Phoma root rot of Edson and European workers.

90

The experience of 1917 to 1919 showed that such epidemics are
favoured by drought which, especially during June, appears to
create a dangerous period in the life of the beet. During certain
years, as in 1921, an early drought reduces the vitality of the beets
so much that they fail to recover and later succumb to late blight
and root rot.

Essic (F. M.). The morphology, development, and economic
aspects of Schizophyllum commune Fries.—U niv. of California
Publ. in Bot. vii, 14, pp. 447-498, 11 pl. 1922.

The author is of opinion that most of the damage to living trees
attributed to Schizophyllum commune is really the work of other,
more slowly growing fungi, such as Polystictus versicolor; no evi-
dence was found that the first-named species is able to infect
healthy trees or that it can grow on living wood except under very
favourable conditions. His inoculations were made on wounded
branches of young apple, pear, and plum trees. A detailed account —
of the morphology and development of the sporophore is given.

ZELLER (S. M.). Morphological differences between WNectria
galligena Bres. and N. coccinea (ditissima).—Abs. in Phyto-
path., xii, 9, p. 442, 1922.

Nectria galligena, described by Bresadola as the organism causing
European apple and pear canker, is distinct from J. coccinea Fries
(N. ditissima Tul.), to which the disease had been attributed
previously. These two species differ morphologically and physio-
logically. Perithecia of V. coccinea from Oregon have walls com-
posed entirely of pseudoparenchyma which stretches up to the
ostiole, whilst in those of NV. galligena from the same district the
pseudoparenchyma extends only three-fourths the distance from
the base, the remainder being composed of long, narrow cells which
radiate from the ostiole, forming a cone. In size and colour of
perithecia the two species are similar. Ascospores of V. galligena
are 14 to 22» in length, those of V. coccinea 8 to 14 uw. Conidia of
the former (Fusarium willkommit) are borne on creamy-white
stromata and average 65-9 by 4 to 5 yw, those of the latter
(Fusariwm sp.) on orange-coloured stromata and measure 54 by 6 p.
Also the conidia of VV. coccinea have more rounded ends and a
curvature of shorter radius than those of WV. galligena.

Husert (E.E.). A staining method for hyphae of wood-inhabiting
fungi.— Phytopath., xii, 9, pp. 440-441, 1922.

This is a rapid method for staining fungous hyphae in wood.
The directions are essentially as follows. Cut sections from 3 inch
cubes of infected wood after boiling them in water for half an hour
or more and soaking in glycerine alcohol (50 parts glycerine,
50 parts 70 per cent. alcohol) for one to two minutes. Wash with
distilled water. Stain from two to five minutes with dilute methyl
violet (4 parts of a saturated aqueous solution of methyl violet
with 12 parts of distilled water), or in some cases full strength
methyl violet for one to two minutes. Wash with distilled water,
examine, and if the violet colour is faint repeat the methyl] violet
staining, or if the counterstain is faint stain again from the begin-

91

ning. Dry slowly on a warming plate, using a cover glass to keep
the sections flat, as dehydration with alcohol apparently removes
the violet stain. If sections curl, use egg albumen or gum arabic
fixative. Add xylol and mount in balsam.

The method has been employed in the routine examination of
woods for the determination of decay, and so far has given satis-
factory results.

Poo.e (R. F.). A new fruit rot of Tomatoes.— Botan. Gaz., |xxiv,
2, pp. 210-214, 1 pl., 1922.

During the summer of 1921 a fungous rot due to Vospora lactis
was observed on fruit of several tomato varieties in New Jersey.
Both green and ripe fruits showed cracks in the surface, apparently
due to some physiological cause, and the fungous growth appeared
in the open cracks of the ripe fruit. The fungus caused a soft rot
which affected the whole fruit in from two to five days. 0. lactis,
which occurs commonly in milk products, cheeses, decaying vege-
tables, &c., forms a dense, greyish-white, prominent, fluffy mycelium
on the cracked tomato fruits, without any great production of
spores. When the rotted internal tissues are incubated, the
formation of abundant spore chains with little mycelium results.
Inoculations from pure cultures rotted wounded ripe tomatoes
readily, but had little effect on the unripe fruit. The optimum
temperature for the development of the fungus is 18° to 20°C.
A slight degree of control was secured by spraying with Bordeaux
mixture, and also by dusting with a dust composed of 16 lb.
anhydrous copper sulphate, 6 Ib. lead arsenate, and 78 Ib. hydrated
lime.

CIFERRI (R.). a ‘carie’ del Pomodoro. {‘ Caries’ of Tomato.]—
Le Staz. Sperim. Agrarie Italiane, lv, 4-6, pp. 145-162, 1922.

Further experiments, carried out since the author's preliminary
paper [see this Review, i, p. 363], confirm the pathogenicity of
Phoma ferrarisit Cif., except that, normally, the fungus produces
a dry rot, while the wet rot described in the first paper is due to
the intervention of Bucillus mesentericus, acting, in the author’s
opinion, in symbiosis with the fungus. The bacterial action is
apparently limited to the secretion of cytase, which disintegrates
the binding substance between the cells without influencing the
cells themselves. The fungus is believed to absorb the cellular
contents’ by osmosis, thus “killing the protoplasm, though it is
possibly aided by the secretion of toxic enzymes.

A symbiotic relationship of this type is not known to the author
to have been described in any other fruit rot. Parasitic action is
reserved for the Phoma, while the saprophytic B. mesentericus
works exclusively in favour of the fungus by removing the
mechanical obstacles to its growth presented ‘by the cell walls. This
condition is termed by the author ‘ unilateral parasitic symbiosis ’,
and it is thought that a similar phenomenon may explain certain
wet and dry rots of potatoes associated with Bacillus amylobacter,
Fusarium solani, and Phytophthora infestans.

Although conclusive proof cannot now be given owing to the
accidental loss of evidential material, the results obtained with

92

parallel cultures of P. ferrarisii and the Ramularia referred to in
the preliminary paper make it more than probable that the latter
is a conidial stage of the former. It is named Ramularia ferrurisix
n.sp. Extended Latin diagnoses for the two new species are now
given.

Infection takes place solely through abrasions in the epidermis.
Hailstorms and insect punctures undoubtedly help in the develop-
ment of the disease, and non-parasitic troubles such as tomato
‘split’ (‘serepolatura’) are thought also to have some influence.
Caries, though very destructive, has so far no great economic
importance owing to its rare occurrence. The only remedial
measure advocated is the immediate destruction of affected fruits.

Exnxiort (J. A.) & CRAWForD (R. F.). The spread of Tomato wilt
by infected seed.— Phytopath., xii, 9, pp. 428-434, 1 pl. 2 figs.,
1922.

Although several authors have expressed the view that Fusarium
lycopersici is transmitted through tomato seed, no one has fully
established this fact. Seed was accordingly collected from wilted
plants in September and October 1921, cleaned by fermentation and
washing, then dried and placed in plugged flasks until 20th January
1922, when plating was commenced. Before plating the seeds were
treated either with sterile water, or with mercuric chloride (1 in
1,000) for two minutes and then washed in sterile water, or with
concentrated sulphuric acid, washed in water, and soaked for two
minutes in mercuric chloride solution. Sterilized blotting-paper
soaked in rice water was found useful in identifying F’. lycopersicz,
as the fungus produced an alizarine pink to old rose coloration on
this medium. Every fungus resembling the wilt organism was
saved and tested by inoculation on tomatoes later. The number of
isolations of F. lycopersici from 400 seeds treated with water only
was 13, from 400 sublimated seeds 2, from 390 seeds treated with
sulphuric acid and sublimate 4.

These results indicate that the organism is carried on the outside
of the seed coat as a rule, but the isolation from seed treated with
sulphuric acid and sublimate suggests that there is Sometimes an
internal infection. The strains isolated were tested on tomato
seedlings and showed considerable difference in virulence, a result
in accord with those previously reported.

ScHWARZ (MARIE B.). Das Zweigsterben der Ulmen, Trauerweiden
und Pfirsichbiume. [The dying of twigs of Elms, Weeping
Willows, and Peach trees.]|—Thesis presented to the University
of Utrecht, 73 pp., 7 pl., 15 figs., 1922.

Dir-BACK OF Etms. This disease, which was first recorded in
Holland in 1919 and became epidemic in 1920 [see this Review, 1,
p- 277, & ii, p. 1], is characterized by the sudden withering of the
twig tips and the simultaneous death of the leaves. No lesions or
fungous growth could be observed on the bark or leaves of dead
twigs. Occasionally the latter were attacked by red mites, but the
injury could not be ascribed to them as they were absent from
a large proportion of diseased trees.

93

Transverse sections of diseased stems show the wood discoloured
over a ring-like area of variable thickness. Such discoloration
varies in intensity and extends into the limbs, trunk, and in the
worst cases even to the extreme ramifications of the root system.
From the fact that this discoloration was present in many trees
showing no outward signs of disease, the author deduces that the
disease existed in a latent stage for a few years before the outbreak
of the epidemic. The discoloration is produced by an alteration of
the walls of the vascular bundles. First the vessels are seen to be
invaded by thin hyphae, against which tyloses are formed which
later disappear. The walls of the vessels then become swollen and
softened to a gum-like consistency, and fuse together. The other
constituents of the wood assume a macerated appearance.

Cultures from dead twigs yielded different fungi, predominantly
species of Fusarium. Cultures from fragments of the discoloured
wood from inside the bigger limbs, however, always produced
a fungus, which gave positive results from artificial inoculations,
the wood being discoloured up to a distance as much as 30 em. from
the point of inoculation, although the other characteristic symp-
toms were not produced. The fungus produced a white fibrous
Cephalosporium-like mycelium (‘A’ stage) on cherry agar, and
under certain conditions yielded yeast-like spores (‘B’ stage).
Later coremia appeared, consisting, when mature, of dark brown to
black stalks, with light-coloured heads composed of an agglomera-
tion of spores held together by mucilage. This stage agrees with
the genus Graphivm, and the author considers the fungus a new
species which she has named G. u/mz, a full description being given
of the various stages.

A few cases of primary infection were found on one year old
shoots. The discoloration was seen to originate in the petioles and
midribs, indicating that the leaves form the principal point of
entry. The fungus is not, however, essentially a leaf parasite.
Infections carried out on twigs showed that the fungus, after pene-
trating the leaf tissue, passes into the midrib, the petiole, and
finally the stem. Leaf scars and wounds also allow its entrance.
Introduced artificially into the wood, the mycelium spreads equally
in all directions, whereas naturally it always progresses from above
downwards and from the youngest wood to the older.

No difference in susceptibility was observed between Ulinus
campestris L. and U. campestris f. monwmentalis Rehd.

The disease is undoubtedly affected by weather conditions, but
data are too meagre to warrant any exact deductions being made.
As to control, the author does not recommend uprooting all infected
trees, as a large proportion may recover by the growth of new
wood over the discoloured ring. Curative treatment is not practi-
cable, but the spread of infection into the main branches might be
prevented by cutting out diseased twigs. Spraying immediately
on the bursting of the leaf buds may be effective, but no trials have
yet been made.

Dir-Back OF WEEPING WiLLow. The Dutch weeping willow,

wie alba var. vitellina pendula S., was heavily attacked in 1920
by the ‘bark scorch’ disease, a detailed description of the symptoms
of which are given. The fungus Fusicladium saliciperdum was

04.

preponderant and is, according’ to Rostrup and Tubeut, responsible
for the disease. The author, however, was unsuccessful in isolating
it and did not carry out infection experiments.

A very considerable number of other fungi were usually present
on portions of willow twigs killed by the Fusicladiwm; infection
trials with pure cultures showed that some of them could be
induced to parasitize living twigs. Especially common were Apo-
sphaeria pulviscula Sace. and numerous species of Phoma. One of
the latter gave positive results from inoculation, and as it did not
correspond with previously described species on Salzx, the author
named it Phoma intricans. A full description of this species is
given. Onanumber of old Fusicladiwm bark lesions, Physalospora
salicis occurred.

Dying of the shoots in autumn after defoliation was caused by
Discella carbonacea. When the terminal bud is discoloured the tip
of the twig soon dies back, always up toa node. The fructifications
are at first covered by periderm through which, later, appear
greyish-white to pink masses of spores... This fungus is known as
one of the most frequent saprophytes of Salix, but the author’s
infection trials and observations showed that, after entering the host
through wounds or dead parts, it can continue to develop vigorously
as a parasite.

Die-BACK OF PEACH. Several fungi are concerned in the die-
back of peach shoots which is very common in Holland. Only
Monilia cinerea, however, is a true parasite. In 1921 this fungus
did little damage to the peaches, probably on account of the hot,
dry weather.

At the beginning of the winter, peaches which had suffered from
mildew were found dying back at their shoots. Such shoots were
covered with Cladosportum herbarum and, to a small extent,
J. cinerea was also present. Ina neglected glass house, C. herbarun
alone was found, causing bark lesions on one or two year old shoots.
At first the lesions were wet and brown; later they dried. They
did not extend and the portion above did not die.

The author believes Botrytis cinerea to be responsible for a
dying-back of peach shoots, especially in glass houses, as she found
a number of dead shoots from which she could isolate no other
organism. The twigs died back progressively, no distinct margin
separating the dead portion from the healthy one. Such shoots
were especially numerous after lice attacks.

On dead shoots, the author frequently found numerous large
black pyenidia of Cytospora prunorum Sace. & Syd. which forms
brown, soft lesions on the twigs. These lesions at first are not dis-
tinguishable from those of Monilia, except that they are located at
any point of the branches and not round the buds. Later, however,
they dry and become grey in colour. A callus is formed round the
sear, which may encircle the stem and kill the shoot above it.
Three strains of C. prunorum were isolated, two of which gave
positive results from inoculations while one did not. The latter
sometimes infected weeping willows when inoculated into them,
and the author considers it a different physiological strain from
the other two.

95

Durrinoy (J.). Tumeurs de Sequoia sempervivens. {Tumours
on Sequoia sempervivens.|—Bull. Soc. Path. Vég. de France,
ix, 2, pp. 148-150, 3 figs., 1922.

On trees of Sequoia sempervivens at St. Mandé and Vincennes,
which had been pruned or otherwise wounded, the formation of
tumours some distance from the wounds was observed, these
growths being always absent on trees left intact. The tumours
developed in the axils of the wounded branches and bore adventi-
tious shoots covered with young leaves. Sections showed that the
growths consisted of a parenchyma formed of giant cells in which
were several cauline axes possessing each a. well-developed pith and
an irregular cambium. The wood was formed of reticulate ele-
ments, irregularly oriented and mixed with pitted cells. The poly-
stelic structure was evidently the result of the coalescence of
several proliferating adventitious buds, stimulated no doubt by
bacterial infection through the wounds. Bacteria were observed in
the parenchymatous cells of the tumours.

VINCENS (F.). Maladies des jeunes plantes et champignons micro-
scopiques nouveaux observés sur Cinchona en Indochine.
| Diseases of young plants and new microscopic fungi observed
on Cinchona in Indo-China. ]— Bull. Soc. Path. Vég. de France,
ix, 2, pp. 125-133, 4 figs., 1922.

The author describes a disease, which he observed in 1920 in
a plantation situated on the mountain of Honba, in Annam, on
young plants of Cinchona ledgervana, and, in a much lesser degree,
of C. succirubra, as well as a hybrid between these two species.
The affected plants, which varied in height between 15 to 20 em.
and 35 to 40 em., were almost defoliated and seemed to be dying.
The outbreak appeared to have become severe recently, judging by
the slight signs on the older as compared with the younger leaves.
The former had a few, small, circular, light brown spots, with a
purple border, or were pierced with circular holes resulting from
the falling out of the tissues within the border of such spots. On
the younger leaves these spots were more numerous, and coalesced |
freely, forming chequered designs which covered the greater part
of the leaf surface. The leaves nearer the top had shrivelled edges,

‘eaten away in places, and were borne on deformed, crooked shoots
on which were abnormal corky outgrowths often of a cankerous
nature. On the hybrids the disease had the same characters,
though the shoots seemed in a more healthy condition. On C. siuc-
cirubra, which was decidedly more vigorous than C. ledgeriana,
badly affected leaves were rare, and the shoots were all healthy.

It is noteworthy that not a single plant seemed to be entirely free

from the disease.

No parasitic organism was observed on leaves still attached to
the stems, but small, black dots were visible on the spots on leaves
that had fallen off some days previously. Similar dots were found
on the wrinkled twigs of dying plants near the ground.

The following fungi found on the three species of Cinchona are
described and figured. On the dead spots on the leaves Phyllosticta
honbaensis n. sp. (rarely on C. ledgeriana, chiefly on C. succirubra)

and P. cinchonaecola n. sp. were found, while P. yersini n.sp.

96

occurred on the lower surface of young leaves still enclosing the
bud (and on the browned shoot bearing them) of a dying plant.
In the suberized bark at the base of the latter plant numerous
fruit bodies of a Phlyctaena—P. cinchonae n.sp.—were found, and
the same fungus was obtained from nearly all the plants examined.
A Phoma—P. cinchonae n. sp.—was present, but less frequently, in
the same situation, while a Dendrophoma—D. cinchonae n. sp.—
was observed on the leaf scars of a diseased plant left in a damp
place after its collection. Partly buried in the wrinkled bark of
the stem base of this same plant were found perithecia of a Physalo-
spora—P. cinchonae n. sp. Finally, a Guignardia—G. yersini
n.sp.—appeared occasionally on the bark harbouring the Phlyct-
aend.

No inoculation experiments were possible, hence the author is
unable to say what share, if any, each fungus has in the production
of the disease. He states, however, that the parasitism of the
species of Phyllosticta does not appear to be in doubt, while the
frequency of the Phlyctaena in the abnormal corky bark of diseased
young plants stamps it also as a parasite. Spraying with copper
solutions had a disastrous effect on the plants, and the practice had
to be abandoned. Subsequent sowings of C. ledgeriana on a different
plateau gave healthy plants.

Moss (E. H.). Observations on two Poplar cankers in Ontario.—
Phytopath., xii, 9, pp. 425-427, 1922.

The first part of this paper deals with the poplar canker caused
by Dothichiza populea Sacc. and Briard. This disease, which was
first reported in America in 1916, was very prevalent at Toronto
in 1921 on 500 young Lombardy poplars planted the previous year,
90 per cent. of the trees being girdled by the fungus. The girdled
area was usually located about two feet from the tip of the stem
and extended for a considerable distance; numerous pycnidia
occurred on the diseased parts and spore horns appeared as early as
4th May.

Later the disease was seen very frequently in southern Ontario,
young shoots from the roots of old trees being killed back and
pustules appearing on the stems. Usually several branches were
affected, the older ones being disfigured by elongated, open wounds,
In Ontario the disease has undoubtedly been present many years,
but the writer’s observations support the view that it was brought
to America from Europe.

The second part of the paper refers to the canker disease of
poplar caused by Cytosporina chrysosperma (Pers.) Fr., which occurs
at various places in the United States, and is now reported for
Ontario, attacking usually Populus deltoides, but also P. italica,
P. balsamifera, P. alba, and Acer saccharinum. Affected trees of
P. alba and P. italica died branch by branch from the top down-
wards. Near Toronto, P. deltoides was found bearing pyenidia
close to wounds in the younger branches and lower parts of the
trunks; in the latter case the trees were rapidly killed. The pop-
lars had apparently been injured by fire and then attacked by the
fungus, a course of events noted by two workers previously.

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

PePLeE Dp MYCOLOGY

Vout. I MARCH 1923

MEINECKE (E. P.). Pathology of quaking Aspen in Utah in rela-
tion to regulation.—Abs. in Phytopath., xii, 9, p. 446, 1922.
The possibility of utilizing quaking aspen | Populus tremula] for
pulp in Utah, where it is common, depends largely on the control
of wood decay, chiefly caused by Fomes igniarius. About 50 per
cent. of all wounds become infected, fire being an important pre-
disposing cause.

Manatn (L.) & PatrourtiarpD (N.). Sur la destruction de char-
pentes au chateau de Versailles par le Phellinus cryptarum
Karst. [On the rotting of the timberwork in the palace of
Versailles by Phellinus cryptarwm Karst.|—Comptes Rendus
Acad. des Sciences, clxxv, 9, pp. 389-394, 4 figs., 1922.

The chief part in the decay of the oak beams in the roof of the
old Louis XIII wing of the palace of Versailles, of which so much
has been heard recently, is played by the fungus Phellinus crypta-
rum Karst. (syn. Polyporus {Fomes| eryptarum Fr.; P. wndatus
Pers.; Boletus eryptarum Bull.). Exceptionally favourable con-
ditions for its development are supplied by the fact that the oak
beams have been covered with plaster having an outer air-tight
coating which prevents air and light from reaching the wood. The
attacked timbers, especially the ends embedded in the masonry, are
reduced almost to the consistency of lint, leaving long, fibrous
strands extending lengthwise in the beams. The decayed wood is
easily crushed together. by slight pressure, but does not crumble to
powder as in the case of wood destroyed by Merulius lacrymans.
All the elements of the wood, with the exception of the long, fibrous
strands (which consist of still lignified membranes occupying the
angles of the cells) and a few transverse bands of tissue (also with
intact membranes), which loosely join them together, are reduced to
shreds from which the lignin bodies and pecto-celluloses have dis-
appeared. In the portions of the beams bordering on the still
sound parts, the initial stages of the rotting could be observed.

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98

One of the most remarkable features of the decay, noted also, but
not so constantly, in timber attacked by Ungulina annosa | Fomes
annosus|, consisted in the complete dissolution of the membrane
limiting the bordered pits of the invaded cells; the wails of the
cells thus appeared riddled with holes long before the rest of the
cell wall was dissolved. In many cases the bordered pits thus set
free were so abundant in the mounting medium of the sections that
they were at first mistaken for accumulations of spores. Medul-
lary rays resist the dissolving action of the fungus longer, and
appear as broad laminae in the midst of the decayed tissues.

The attacked cells were invaded by numerous widely and irregu-
larly branching hyphae without clamp-connexions, 0-5 to 2 or 3p
thick, which formed an abundant and loose mycelial felt in the
partly destroyed vessels and in cracks in the wood. Perfect fructi-
fications of the fungus, a full description of which is given, appear
in the form of more or less orbicular plates, up to 20 cm. in diameter,
attached to the substratum by one central point, or by several
points in cases where several fructifications have coalesced. Besides
this normal form, specimens are often found reduced to a simple,
smooth or undulated membrane, easily detachable from the sub-
stratum and bearing none of the characteristics of a fruit-body.
The fungus has no cystidia, and the authors did not succeed in
finding spores. In very wet conditions the fungus exudes numerous
droplets of liquid which, on drying, leave irregularly-dispersed,
black spots on its surface.

Phellinus cryptarum is generally found in cellars and mines, and
is common in damp, dark, and non-aerated places; the authors are
not aware of its having been previously recorded as destroying
woodwork in buildings. It has been identified with Fomes annosus
by some authors, but differs from the latter both in its fructifica-
tions and in the nature of the wood decay it causes. Montagne
wrongly identified as Phellinus cryptarum another fungus Lepto-
porus | Fomes] rufo-flavus B. & C. which is not uncommon in green-
houses, mines, &c., and which has also been described by Rabenhorst
as Polyporus braunit. Quite recently another case of the rotting
of oak beams supporting the ceiling of a room, kept closed for
fifteen years, in a school near Etampes, has been examined by the
authors and found to be due to Phellinus cryptarum. They con-
sider this fungus therefore as a dangerous wood destroyer, but
believe that good ventilation and dryness are sufficient to check its
development.

A certain number of the beams examined at Versailles were
worm-eaten, the insects concerned being chiefly Xestobium rufovil-
losum Deg. and (less often) Anobium domesticum Geoftr.

Levy (E. B.). Investigation of dry rot of Swedes.— New Zealand
Journ. of Agric., xxiv, 6, pp. 336-348, 6 figs., 1922.

The investigation of the dry rot disease of swedes (Phoma
napobrassicae) during 1920-21 was mainly directed towards soil
sterilization, it having been conclusively demonstrated that the
organism overwinters in the soil. The trials were conducted as
follows, the quantities being calculated to the acre and the material
broadcasted on the ploughed surface in all the treated plots except

99

15, 16, and 18. Plot 1, control; plot 2, burnt lime, 2 tons ; plot 3,
burnt lime, 8 tons: plot 4, burnt lime, 4 tons; plot 5, control ;
plot 6, sulphur, 3 cwt.; plot 7, sulphur, 9 ewt.; plot 8, control;
plot 9, copper sulphate, 3 ewt.; plot 10, copper sulphate, 9 cwt.;
plot 11, control; plot 12, iron sulphate, 3 ewt.; plot 13, iron sul-
phate, 9 ewt.; plot 14, control; plot 15, formalin, 1 pint to 30 sq.
yds.; plot 16, carbon bisulphide, 1 pint to 30 sq. yds.; plot 17, con-
trol; plot 18, Bordeaux mixture 4-6-40, 1 gall. to 2 sq. yds. The
best results were got on plots 6 and 18, all the others giving
over 50 per cent. dry rot after 5 months except plots 13 and 14,
which had over 40 per cent., plot 17 over 30 per cent., and plot
10 where there was a serious reduction of germination and about
25 per cent. rot. Even in plots 6 and 18 control was inadequate,
and the method cannot be recommended for farm practice. The tests
were carried out on land which had carried two consecutive swede
crops, the second being rather severely attacked by’ the disease.
A“similar series of tests was repeated on adjoining land not
previously in swedes, and here the percentage of infection, taking
the series as a whole, was only 12, as against 56 per cent. in the
field previously in swedes, the division at the junction of diseased
and healthy land being quite sharply marked. This 12 per cent.
of infection may have been due to a slight attack of dry rot on
a crop of soft turnips grown on the same area two years earlier.
The infection on the land not previously in swedes was definitely
patchy, the remainder of the crop being fairly sound, while on the
corresponding area previously in swedes there was infection
throughout. Infection likely to have arisen from seed-borne spores
was rare.

It is apparent from these results that the organism overwinters
in the soil, and forms more or less numerous centres of infection
which may involve the whole crop. The subsequent spread is
certainly wind-borne, but the radius of infection is quite short, the
patches rarely exceeding 20 ft. in diameter. Attempts were made
to reduce the secondary wind-borne infection by growing the roots
close together to form a denser leaf-cover, and also by interplanting
thousand-headed kale with the swedes. The latter method proved
very successful, the kale lasting well and affording considerable
protection to the swedes. Such preventive measures, however, are
only effective in reducing secondary wind-borne infection, and are
of no use against the primary or seedling stage of the disease.

A suitable type of crop rotation appears to be the only reliable
means of control, and suggestions for a six years’ course are given.

ParnE (S. G.) & Lacey (MarGaret 8.). Chocolate spot disease or
streak disease of Broad Beans.—Journ. Min. Agric., xxix, 2,
pp. 175-177, 1 fig., 1922.

The causal organism of the chocolate spot or streak disease of
broad beans is Bucillus lathyri Manns and Taub., which causes
streak in sweet peas and stripe in tomatoes, and is known to attack
many leguminous plants. It is considered probable that field beans
are seldom, if ever, entirely free from this disease, but serious out-
breaks occur only under exceptional weather conditions, as in the
summer of 1920 for instance, when a heavy epidemic throughout

100

a large part of England and Wales was preceded in many places by
hot, wet, and thundery weather. In 1921, on the other hand, the
exceptionally dry weather soon checked the disease which made its
appearance in the early spring ; the plants quickly recovered from
the attack, and a month later showed no sign of injury.

In a typical case described, the first symptoms of the disease—
small, purplish-brown spots on the leaves and long or short streaks
of a rich bronze colour on the stems—appeared in the last week of
May 1920 on beans planted in October 1919: at the end of the first
week in June the plants were largely defoliated, the remaining
leaves showing a good deal of blackening. About the middle of
July the stems in the central portion of the field were beaten down
by rain, all the leaves had been shed except a bunch at the top of
the stalks, and the whole plants were being rapidly rotted by a
Botrytis which, in all cases observed, followed closely after the
streak disease. In many instances the plants on the borders of the
field were iess severely attacked, the conditions in the outer, m@re
exposed, portions being drier than in the centre and less favourable
to the spread of the disease. During 1920 the epidemic spread
apparently from west to east, and this observation seems to suggest
wind dispersal of the causative organism, which may find entry
into the host through the stomata of the leaves. There is also
evidence that the organism is carried on the seed of winter beans,
and especially on those which have been bored by the bean beetle
Bruchus rufimanus; the plants may be inoculated by this beetle’
when laying its eggs, and the young larvae which develop in the
pod may infect the seed when boring their way in.

The authors suggest as a possible means of control, the applica-
tion to land on which the disease has occurred to a serious extent
of a good dressing of potash, since it is known that this treat-
ment has been successful in checking stripe in tomatoes. The seed
should be carefully examined and rejected if showing an excessive
amount of boring by beetles; before sowing it should be soaked
for ten minutes in weak lysol or formalin, or dressed with one of
the tarry preparations supplied for seed sterilization.

HunGerrorp (C. W.). A Fusarium blight of Spinach.—Abs. in
Phytopath., xii, 9, p. 447, 1922.

A rather serious disease has recently appeared on spinach in
Idaho, attacking the plants when young, stunting their growth,
causing curling of the leaves, and finally killing them. A species
of Fusarium, which appears to be new, was constantly isolated
from the interior of the crowns and roots of diseased plants, and
plants grown in sterilized soil inoculated with this fungus developed
the characteristic symptoms of the disease.

Barss (H. P.). Destructive rust (Puccinia subnitens Dietel) on
Spinach in the northwest.—Abs. in Phytopath., xii, 9, p. 446,
1922.

In 1922 the vegetable growers of Oregon sustained heavy losses
on their early and late crops of spinach owing to the serious damage
caused by Puccinia subnitens.

Distichlis spicata, the teleutospore host of P. subnitens, was

101

found to be one of the three commonest grasses growing in the
vicinity of the spinach beds, and experiments at Corvallis have
demonstrated that rust sporidia from D. spicata can infect the
cultivated spinach.

LEonTAN (L. H.). Stem and fruit blight of Peppers caused by

' Phytophthora capsici sp. nov.— Phytopath., xii, 9, pp. 401-408,

2 figs., 1922.

A disease which attacks the pods and branches of chilli peppers
(Capsicum annwwm) in New Mexico was found to be caused by
a species of Phytophthora. It usually appears at the beginning of
the warm, rainy season in June or later. Small, water-soaked, dull
green spots form on the fruits, and develop into elongated lesions
that dry up and become straw-coloured. Lateral spread is limited,
but the fruit is penetrated and the seeds attacked. The latter are
sometimes killed, but remain viable when only the seed coats are
infected.

From the fruits extension to the branches takes place, the young
shoots being rapidly blighted and destroyed. Usually progress is
arrested at the older branches or the main stem. Secondary infec-
tions caused by liberated zoospores may occur, especially at the
forks, causing girdling lesions which kill the parts above. Lateral
spread is much more marked on the branches than on the fruit.
The roots are not attacked, except for local lesions on the fine,
lateral roots.

The fungus was isolated and grown in pure culture, from which
successful inoculations were invariably obtained. It is regarded as
a new species, to which the name P. capsici is given. It falls in
Rosenbaum’s Phaseoli section, characterized by basal (‘amphi-
gynous’) antheridia. From the other members of this group it is
distinguished by its gnarled, tuberculate mycelium; the large,
though very variable, sporangia (35 to 85 by 21 to 56 yu or occasion-
ally up to 105, long); the abundant, slightly wrinkled, brown
oospores, 25 to 35 in diameter; and the absence of chlamydo-
spores.

Infected seeds are an important agent in dissemination. Diseased
pods are often not discarded owing to the slight external symptoms.
When their seeds are planted the fungus grows out and fructifies
in the soil. Infection takes place by zoospores produced in the
soil and spattered by rain on to the lower fruits that hang down
near the ground.

It is believed that careful seed selection and spraying should be
effective in controlling the disease, though no experiments in control
have been tried as yet.

Crepin (C.). Un Oidium de la Betterave. [An Vidiuwm of the
Beet.|—Bull. Soc. Path. Vég. de France, ix, 2, pp. 118-119,
_ 1 fig., 1922.

An Oidiwm was observed at Grignon in the autumn of 1921 on
beetroot [Beta vulgaris] (both fodder and sugar beet) and on Beta
marituma. The mycelium is very delicate, and covers the whole
of the leaf surface on both sides. The conidia are unusually long,
mostly 30 to 40 1; those below 27 are rare, while many are over

102

40, and a few reach 50y. Their width varies within narrower
limits, between 9 and 12 or 18 p, the average being 10 or lly. The
conidiophores are usually very long, and terminate in a single
conidium. Mycelium, conidiophores, and conidia, as is common in
the Erysiphaceae, are covered with small, hollow protuberances.
The appressoria are lobed. The conidia of this fungus agree in
length with those described in Microsphaera betue Vanha (44 by 15
to 20 yz), but they are very much narrower.

Poo.e (R. F.). The Sclerotinia rot of Celery.—New Jersey Agric.
Exper. Stat. Bull. 359, 27 pp., 15 figs., 1922.

A disease caused by Sclerotinia ‘libertiana, affecting all the
varieties of celery grown in the greenhouses in the muck bog areas
of Bergen County, N.J., has been very destructive for a number of
years. It particularly affects seedling plants, which are grown
under glass from seed sown in February to be set out in the fields
in April; in such cases losses up to 95 per cent. of the crop may be
caused. Severe damage in the field has not been observed. The
affected seedlings are attacked at the collar and fall over, a white
cottony growth of mycelium developing on the leaves and stem after
they fall. Sclerotia may appear very quickly and undoubtedly
carry the fungus over in the soil. They may bear apothecia in the
houses from March to June. Sometimes a watery soft rot, similar
to that in the field outbreaks, is caused by the attack of this fungus
on celery in storage.

Lettuce drop is caused by the same fungus, and cases have been
observed where infected soil from lettuce fields has served to cause
infection in celery houses. It appears: to be a common practice
to grow lettuce in rotation with celery, and this intensifies the
clisease.

The control measures recommended are the use of clean soil, or
treating the infected soil with a formaldehyde solution (8 pints of
formalin to 50 gallons of water, applied at the rate of 1 gallon to
the square foot, 7 to 14 days before sowing), or steam steriliza-
tion of the beds, which, however, is not always practicable for
small growers. The question of ventilation should also receive
attention. Greenhouses constructed so as to be exposed to the sun's
rays in all their parts, and fitted with proper ventilating devices,
have consistently shown the smallest percentage of infection.
Removal of diseased plants is effective if done early.

The author states that S. minor has so far not been observed in
the bog soils of New Jersey, but it has attacked upland lettuce.

Rivier (A.). Observations sur le Sclerotinia libertiana Fckl.
[Notes on Sclerotinia libertiana Fckl.]|—Bull. Soc. Path. Vég.
de France, 1x, 2, pp. 184-1387, 1922.

‘Lettuce drop’, caused by Sclerotinia libertiana Fckl., is respon-
sible for heavy losses in the south-eastern portion of France, halt
the crop being frequently destroyed by it in the Hyeres (Var)
district. The virulence of the disease seems to reach its height in
November, just before the crop is gathered. At the Agricultural
College of Montpellier, during the spring, the fungus frequently
attacks melon plants grown under glass on manure beds. Infection

103

occurs chiefly on the stems, especially at the point of bifurcation,
which becomes characteristically livid and leaden in hue, the dis-
coloration spreading somewhat rapidly. In a short while, under
favourable conditions of humidity, the affected portion is covered by
a dense, white mycelium, and the stem frequently breaks at this
point. Proper ventilation and drying of the frame or house, as
soon as the attack is noticed, usually prevents further spread.
The same fungus was found on Pyrethrwm cinerariaefolium, growing
in an experimental field attached to the Pathological Station at
Montpellier. Cross-inoculations on lettuce, melon, and Pyrethrui,
and a comparison of the apothecia resulting from sclerotia collected
from all three plants, established the identity of the three diseases.
Pyrethrum is believed to be a new host for S. libertiana. The
mode of attack on this plant follows the usual lines, that is to say
the spread occurs by means of the mycelium, which is capable of
running over the surface of the ground from plant to plant provided
the soil is damp enough. The fungus enters the host at the soil
level, the stem is covered with the white mycelium, and the plant
dries up. On the surface of the stem in the vicinity of the collar
sclerotia are formed, which vary in size from a grain of buck-wheat
to one of oats. The disease in Pyrethrum does not appear to be of
great importance, and is believed to be associated with the heavy.
wet soil in which the plants were growing, and the vicinity of
lettuce, melon, and other plants susceptible to attack.

Cocoe rot.— Journ. Jamaica Agric. Soc., Xxvi, 2-3, pp. 62-64, 1922.

Referring to the prevalence of cocoe [ Xunthosoma sagittifolium |
rot, the writer quotes a report by Ashby in 1912 to the effect that
the disease was caused by a hitherto undescribed fungus, to which
he gave the name Hormisciwm colocasiae [given by Ashby as H.
zanthosomae u.sp., and then changed to Vasculomyces xanthosomae
n.g., n.sp. in Bull. Dept. Agric. Jamaica, N.S. ii, p. 151, 1913].
The fungus gains admission to the water-conducting system either
from previous infection of the ‘seed’ used for planting, by means of
infection of the freshly cut surface of the planted tuber, or through
any subsequent wound of the root or tuber. The fungus obstructs
the water-conducting channels, the bundles turn brown, and the
internal tissues shrink and split. When the split extends to the
surface, insects, worms, and other fungi enter and increase the rot.
The first method of infection named above is very common; the
fungus in the vessels extends far beyond the discoloured portions,
and may still be present, though causing no obvious signs, in the
material used for planting.

The ‘Commander’ variety appears to be specially liable to the
disease, which presents certain analogies with the Panama disease
of bananas. Continuous planting on infected soil naturally increases
the trouble, and rotation of crops should be carefully practised.
Maize and peas make good alternative crops to cocoes. The old
cocoe roots should be grubbed out and burnt, the land limed, and
trenches put through it. The disease is very severe on water-
logged soil. The burning of diseased stumps and other refuse has
additional advantage of providing a supply of wood-ash for the
soil.

104

ViverT (E.). Le mildiou de la Vigne. Dates desinvasions. Les
périodes critiques des invasions de mildiou. [Mildew of the
Vine. Dates of invasion. The critical periods of mildew
invasion. |—Revue Agric. Afrique du Nord, xx, 139, pp. 200-
202, 1922.

From 1908 to 1913 the date of the first appearance of mildew
[Plasmopara viticola] spots on vine leaves at the Maison-Carrée
Agricultural Institute in Algeria oscillated between the 2nd and
19th of May. As the period of incubation is seven days, it might
be concluded that it would suffice to apply the tirst preventive
treatment during the last week in April. But events in 1921, when
mildew spots appeared on the 16th April, upset this calculation, and
on searching back through the records the author found that the
earliest date of its appearance in the Mitidja district noted since
1888 was the 13th April. It follows that by thorough spraying in
the last days of March or at the beginning of April the young shoots
can be efficiently protected against attacks derived from the germina-
tion of the resting spores.

A comparison of the dates shows that the successive attacks of
Plasmopara during the two very bad years of mildew, 1908 and
1921, synchronize almost completely, if one ignores the unusually
early first invasion in 1921. ‘This confirms the observations made
in vineyards round Algiers, that the disease is particularly to be
feared during May, notably round about the 15th of that month,
coincident with the flowering period. This period the author
designates as the first critical period for mildew. Though occurring
more rarely, the invasions of ‘brown rot’ (mildew on the fruit)
generally take place during the last half of June, towards the 20th
of that month, which may be called the second critical period.
This coincides with the rapid development of the fruit. Hence it
is necessary to concentrate preventive treatment on the two critical
periods, in May and in June. During rainy weather, or when mists
occur in these periods, adhesive mixtures must be employed at least
once a week, and in addition the bunches should be dusted with
a fungicidal powder.

WALKER (J. C.). Seed treatment and rainfall in relation to the
control of Cabbage black-leg.— United States Dept. of Agrve.
Bull. 1029, 26 pp., 1 fig., 2 pl., 1922.

None of the four methods of cabbage-seed disinfection tested,
viz. with hot water, dry heat, formaldehyde, and corrosive subli-
mate, can be relied upon for the complete eradication of the
blackleg fungus, Phoma lingam, without severe injury to the seed.
Seed treatment, however, reduces the number of primary centres of
infection by destroying a considerable proportion of the organisms
present on the seed. It is doubtful whether dry heat can be used
on a commercial basis, because of the wide range of susceptibility
to injury in different lots of seeds and because of the difficulty of
application. Hot water treatment was proved not to be superior
to the chemical fungicides, and in view of the awkwardness of its
application it is not at present considered suitable for general use.
With the chemical fungicides treatment stronger than a 1 in 240
solution of formaldehyde or a 1 in 1,000 solution of corrosive

105

sublimate for thirty minutes, followed by rinsing, is often unsafe,
though some lots of seed will stand much more, especially with
corrosive sublimate. Of these two treatments, the latter seems to
be slightly superior in controlling the fungus.

Experiments were also made in 1919 and 1920 to study the effect
of rainfall on the development of the disease in the seed-bed. In
1919 untreated seed known to contain about 2 per cent. infection,
was sown on 14th May in a bed divided into four plots, of which
the first was left exposed to natural weather conditions, the second,
exposed as the first, was sprinkled with water several times a week
during dry weather, the third was covered with a cold frame during
rains, and the fourth was covered every evening and during rainy
weather. The protected plots were watered artificially, care being
taken to avoid splashing and the consequent distribution of pycno-
spores. A few infection centres appeared in all plots about the
9th June after a period of heavy rain from the lst to the 5th June.
The subsequent spread of the infection was greatest in the first
two plots, while in the two protected ones very little spread took
place. The results showed clearly that when the splashing action
of rain was eliminated spread was slight, while it was enhanced
when the plants were artificially sprinkled. Although plot 3 was
exposed to numerous heavy dews, these were apparently insufficient
for the dissemination of spores to any appreciable distance. The
experiments of 1920 confirmed these results. The author considers
therefore that in regions where cabbage piants are grown in open
seed-beds, variation in the rainfall during the period between the
appearance of primary pycnidia and transplanting has a very great
influence upon the development of blackleg. Where the plants are
grown in covered cold frames or in greenhouses the disease can be
checked by avoiding the splashing of water.

TayLor(W. A.). Report of the Bureau of Plant Industry. 34 pp.,
1922. ;

This report covers the year ending 30th June, 1922. The Bureau
of Plant Industry of the United States Department of Agriculture,
at Washington, deals with all problems of plant production and, in
addition to the head-quarters organization, maintains field stations
and conducts experiments in all parts of the United States. Much
of its work is carried on in co-operation with the officials of the
different States. The scientific work is organized in thirty-two
sections, eight of which are wholly occupied with plant pathology
(exclusive of insect troubles which are the concern of the Bureau of
Entomology), while in several of the others, as for instance the
sections for cereal, tobacco, and sugar-plant investigations, the study
of diseases of special crops is an important part of the work. On
lst September, 1922, the numerical strength of the Bureau staff
was 1,990, of whom 672 were employed at Washington and 1,318
outside.

Amongst the most important results of the year’s work, of
interest to us, mention may be made of the following. With wheat
the introduction into cultivation of rust-resisting varieties is steadily
proceeding. Kota, a bearded, hard, red, spring wheat, discovered
in 1918, has been tested at thirty experiment stations and found to

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106

be nearly equal to the most resistant durum varieties in withstand-

ing stem rust [Puccinia graminis]. The campaign for the eradica- —

tion of barberry in the stem rust areas is now in its fifth year.
Thirteen of the north-central wheat-growing States have enacted
legislation requiring the removal of common barberry bushes.
Altogether 5,625,289 bushes have been located and 4,457,638
removed during the entire campaign. True take-all (Ophzobolus
graminis [cariceti]) has been found on wheat in six States and it
has been shown that the ‘ rosette’ disease, the cause of which is still
unknown, is distinct both from take-all and the Helminthosporium
disease. The latter affects chiefly durum wheat and no effective
control measures are known.

The complex group of diseases causing root, stalk, and ear rots of
maize are of great importance in many States, losses of over 30 per
cent. having been experienced in certain trials during the year.
The wheat scab fungus, Gibberella sawbinetiz, is one of the impor-
tant parasites concerned, as is also the dry rot fungus Diplodia zeae,
while Fusarium moniliforme is commonly associated. One or more
species of Cephalosporium cause another type of disease, character-
ized by a purple discoloration of the stalks and leaves, browning of
the fibrovascular bundles, and barrenness. Bacteria are also asso-
ciated with these fungi.

Sugar-cane mosaic disease has been found to occur in all the
cane-growing States, and a complete survey of its incidence has
_ been made. The destruction of diseased plants and the use of healthy
seed are the only known methods of eliminating it, and parts of
Porto Rico and Florida have now been practically cleared of the
disease in this way. The immune variety Kavangire [ Uba] promises
to displace the susceptible varieties in badly diseased areas.

The citrus canker [Pseudomonas citri] was thought to have been
completely eradicated from areas of commercial citrus fruit pro-
duction, but a centre of infection on grapefruit was discovered in
Florida in May 1922, and about 750 trees were found to be involved.
This outbreak is being dealt with. A few other infected spots were
found in Alabama and Mississippi, there are scattered diseased trees
in Louisiana but not in the commercial producing area, and parts
of Texas still require attention. Further experiments with the
Bordeaux mixture and oil emulsion spray confirm the previous con-
clusion that it will effectively and economically control melanose
and stem-end rot of citrus fruits [| Phomopsis citri] if applied to the
young fruit.

The group of so-called degeneration diseases of potatoes—mosaic,
leaf roll, and related troubles—has become the greatest handicap to
potato improvement in the United States and causes heavy loss
throughout the country. Investigations during the year under
review indicate that both streak and curly dwarf are closely related
to this group and can be transmitted by juice inoculations. Roguing
the crop, in localities where the percentage of mosaic and aphid
infestation is low, has reduced mosaic from 10 per cent. to 1 or 2
per cent. in one season. Varieties differ considerably in their
reaction to the disease, but resistance is less common than previously
believed.

Cucumber mosaic can be caused by infection from the common

"

107 ¥

milkweed [Asclepias], which is probably an important source of \
the disease as it is frequently found near the cucumber fields.

Amongst forest trees it is stated that ‘blueing’ or blue stain,
caused mainly by species of Ceratostomella, is the most important
degrading factor in air-seasoned southern yellow pine [Pinus
palustris] and causes deterioration of many other timbers. In the
south the control of this and of mould fungi is perhaps the biggest
problem in the industry. The ring-scale fungus, Trametes pini,
has been found to cause all but a small part of the loss through
decay in the Douglas fir forests of Oregon and Washington, which
contain nearly one-fourth of the remaining stand of saw timber in
the United States. Losses of 20 per cent. are said to be common.
Affected living trees can now be recognized by external indications,
a circumstance that will be very helpful in the management of the
forests,

Chestnut blight [Zndothia parasitica] continues to spread south-
ward. Certain surviving American trees in the infected area are
being propagated from as being evidently resistant. Search is
being made for resistant or immune varieties of chestnuts both in
the United States and in other countries, in addition to attempts to
secure these qualities by breeding.

Since attempts to exterminate the white pine blister rust | Cronar-
tiwm vibicola| in the eastern States were abandoned in 1917, on
the discovery that the disease had obtained too firm a footing,
efforts have been concentrated on the development of practical
methods of control, which would ensure the continued growth of
white pines in spite of the presence of the fungus. These consist
mainly in the eradication of cultivated and wild forms of currant
and gooseberry bushes | the chief alternate hosts of the fungus] within
900 feet of the pines. It is stated that control measures can be
applied by pine owners at economically practicable rates and that
any stand of white pine, large or small, can be adequately pro-
tected. But it is considered that these measures will fail in their
object unless they are applied generally within the next few years.
The chief event of the year in regard to this disease was its dis-
covery in British Columbia and the Puget Sound region of
Washington State [see this Review, ii, p. 4]. Prompt action has
been taken to determine the extent of the invasion and, if possible,
to eradicate or control it. The Canadian blister rust quarantine to
prevent western migration of this disease was enforced in 1916, but
the age of the infections found in British Columbia in 1921 showed
that it had succeeded in reaching that area prior to the quarantine.

Verslag over het jaar 1921. Departement van den Landbouw
in Suriname. |Report of the Dept. of Agric., Surinam, for the
year 1921.] 92 pp., 1922.

The report contains a few references to subjects of phytopatho-
logical interest.

Bud rot of coco-nuts caused so much damage in a plantation of
2-3 hect. in extent that further cultivation had to be abandoned.
Oil palms (Elaeis guineénses) also continued to die of bud rot, only
one palm being left alive out of the 130 African specimens that
were planted in 1916. Hibiscus cannabinus, grown in small

108

quantities for experimental purposes, was severely attacked by
a root disease. H. sabdariffa will probably, it is thought, prove
much more satisfactory than the former species as a substitute for
Bengal jute.

Ler (H. A.). Observations on previously unreported or note-
worthy plant diseases in the Philippines.— Philipp. Agric.
Rev., xiv, 4, pp. 422-434, 8 pl., 1922.

Notes are given on the following diseases of plants in the Philip-
pine Islands:

Citrus. Psorosis or California scaly bark, a disease of unknown
origin, causes heavy losses on the sweet orange (C. sinensis) and has
apparently been present for many years. Florida scaly bark or
nail head rust also occurs in Batangas on this host but does little
damage. Foot rot, reported to be due to Phytophthora terrestria
[P. parasitica], severely attacks seedling trees of sweet orange and
trees budded on sweet orange stock, being probably, next to psorosis,
the most serious disease of citrus in Oriental countries. Bark rot,
due to an unknown cause, is responsible for heavy losses to mandarin
oranges (C. nobilis) in the Philippines. Experiments indicate that
the disease may be controlled by spraying. Pink disease (Cortecowm
salmonicolor) is serious in highly cultivated groves but is readily
controllable. Citrus canker (Psewdomonas citri) is widely distri-
buted, but most of the varieties grown are resistant. Withertip of
limes (Gloeosporium limetticolum), withertip of grapefruit and sweet
oranges (Colletotrichum gloeosporioides), mottled leaf, greasy spot,
and sooty mould (Meliola sp.) all occur but are of no great
importance.

BanaNA (Musa sapientum). Wilt (Fusarium cubense) was
detected for the first time in the Philippines in June 1920 and is
probably widely distributed throughout the islands. The occurrence
of the disease is sporadic; one plantation may be severely affected
while adjacent groves remain immune. Heart rot, causing a decay
of the terminal bud accompanied by a black discoloration and un-
pleasant saline odour, is common but does not cause extensive
injury. The author believes that it has not yet been reported from
other countries. Freckle (Phoma musae), a disease occurring on
many varieties of banana including the wild banana and abaca, and
in isolated parts of the country, is probably endemic. It is of no
great importance at present.

Apaca (Musa textilis). Heart rot, similar to that of banana, is
due to a fungus not yet described, and causes a continuous slight
reduction in the total annual production of Manila hemp. A root
rot that usually follows the attacks of the root borer (Cosmopolites
sp.) is mentioned, while another root rot, associated with a species
of Marasmius and apparently not previously reported, occurs occa-
sionally. Leaf spot diseases of shght importance also have been
observed.

StsaL, ZapupeE & Maaury (Agave spp.). Anthracnose (Colleto-
trichwm agaves) was first observed in 1921 on sisal (A. cantula) and
zapupe (A. zapupe), having probably been introduced on zapupe
plants from Mexico. The disease is extremely serious on the latter,

109

the plants being rendered useless for fibre production. Sisal and
maguey are less severely affected.

PINEAPPLE. Pineapple wilt [cause not specified] is now recorded
for the first time in the Philippines, where it occurs on Hawaiian
varieties only. On one estate the losses were fairly severe, but the
disease has not made much headway as yet, and should be easily
eradicable. The rot due to Thieluviopsis paradoxa is very general
and severe on the leaves, suckers, and fruits.

Topacco. Root rot (believed to be that due to Thielavia basi-
cola) is the most serious disease of field tobacco in the Philippines,
though it has not been previously reported. Bacterial wilt
(Bacterium solanacearum), Sclerotium rolfsii, and the Cercospora
| nicotianae] leaf spot are all present but do not cause serious losses,
Mosaic disease affects a large proportion of mature plants but the
damage it causes has apparently not yet been recognized by the
growers. .

Coco-Nut. Bud rot is reported from all the most important coco-
nut producing districts of the Philippines. The Bureau of Agri-
culture is carrying on a campaign for its eradication. Leaf spot
(Pestalozzia palmarum) is widespread but not serious, the palms
usually outgrowing the disease after a few years. Stem bleeding
disease, as described from Ceylon [Thielaviopsis paradoxa], occurs
in Mindanao and Sulu. In the former district especially it curtails
the life of the palms. ,

SuGAR-CANE. Besides smut (Ustilago sacchari), mosaic, and Fiji
disease, the following also occur: pineapple disease (T'hielaviopsis
paradoxa), Sclerotiwm rolfsii, top rot, rust (Puccinia kuehnit), wilt
(Cephalosporivm sacchari), root disease (Marasmius sacchari), leaf
spots caused by Lakerophomu sacchari, Leptosphaeria sacchari,
Phyllachora sacchari, Cercospora kopkii, and Pestalozzia fuscescens
var. sacchari, sooty mould (Meliola arundinis) banded sclerotial
disease (Sclerotiwm sp.), and downy mildew (Sclerospora sacchar?).
A disease somewhat resembling sereh, but believed to be distinct, is
termed red vascular disease. It is considered to be identical with
a sereh-like disease of D 1135 cane in Hawaii. Red rot (Colletotri-
chum faleatum) has not yet been found on cane stems in the
Philippines but C. falcatum attacks and kills the leaves in damp,
warm weather. Melanconiwm sacchari has not been observed to
cause any injury. The flowering parasite Aeginetia indica often
causes disastrous losses in certain localities.

Cook (M. T.). Report of the Department of Plant Pathology
of the New Jersey Agricultural College Experiment Station

for the year ending June 30, 1921. pp. 423-475, 3 pl., 1922.

A list is given of the problems under investigation, and the most
important diseases of the year are classified under the plants
attacked. Dr. W. H. Martin contributes a report of potato-spray-
ing tests, which indicated that five applications of Bordeaux mixture
for the control of early blight [Alternaria solani] and tip burn
Sih good results, the 5-5—50 being better than the 44-50 formula.
etails of his experiments in the control of potato seab [ Actinonvyces
scabies| with sulphur are also given. Mr. R. F. Poole investigated
root rots of celery and horse-radish and carried out experiments in

110

the control of field diseases of sweet potatoes. Most of this work
has been already noticed. Eggplant wilt (Verticillium albo-atrwm)
was studied by Mr. C. M. Haenseler; the disease is serious in New
Jersey and the results of inoculations showed that it may cause
severe stunting and reduction in yield even when typical wilting is
absent. He also continued his experiments in spraying for the con-
trol of pear fruit and leaf spot (Fabraea maculata). Satisfactory
control was eftected by four applications of lime-sulphur (1-40),
Bordeaux mixture (3—4—50), ‘pyrox’, and self-boiled lime-sulphur
(8-8-50), but only the last caused no spray injury.

Under the title ‘Foliage injuries’ Dr. Cook deals with the
excessive leaf-fall of various deciduous trees, attributable mainly to
the sudden alternations of warm weather and frost in the spring of
1921. In the case of the cherry, the leaf spot fungus Cylindro-
sporium padi was also involved. Leaf scald of urban shade trees
was caused by the lack of water and food due to the system of
drainage in towns, which is directed to preventing the percolation
of water into the soil, combined with excessive transpiration. It
can be controlled to some extent by pruning out 25 per cent. of the
branches in the autumn, by the application of fertilizers in the
spring, and by loosening the soil round the roots of the trees.

Departmental Activities: Botany.—Jouri. Dept. Agric. S. Africa,
iv, 5, p. 405, 1922.

A serious outbreak of anthracnose (Colletotrichuin trifolii) of
lucerne has recently occurred in the Uitenhage district. It gener-
ally affects the stems and petioles, on which elliptical, sunken spots
develop, the leaves being rarely attacked. The plants are said to
suffer the greatest injury when the seedlings are exposed to pro-
longed dry weather, and again during the ripening of the seeds
when the effects are most severe on the stem just above the ground
level. No definite control measures are known, the only reliable
remedy being apparently the raising of resistant varieties.

One of the most serious troubles in the nursery, and the most
destructive disease affecting apple stocks, is the Sclerotiwm disease
of Northern Spy stocks, the control of which requires constant
vigilance. The stocks frequently die out in patches, the collar
being covered with white mycelial strands, and minute, hard,
brownish sclerotia, not unlike lucerne seed, being found in the
soil. The fungus can spread rapidly through the soil. Rotation
would appear to be the most effective preventive measure, the
site of the nursery being changed frequently. The roots of all
stocks, on transplanting, should be sterilized by dipping in a
formalin solution. Dead plants, and those adjacent to them, must
be incinerated and the soil in which they were growing disinfected.

NowEL. (W.). Diseases of Cacao in Trinidad.—Proc. Agric. Soc.
Trinidad and Tobago, xxii, 5, pp, 483-493, 1922.

This is a semi-popular account of fungous diseases affecting cacao
plants in the British West Indies, especially Trinidad. Diplodia
| theobromae|, which was long believed to be the cause of die-back,
is regarded by the author as a weak parasite, the primary cause of
this disease being faulty soil and other cultural conditions. The

111

cacao tree is, by its nature, suited to humid conditions; it requires
a considerable depth of soil and a fairly abundant supply of humus,
and these requirements are usually met by treating the plantations
so as to approximate to forest conditions, as, for instance, by inter-
planting with shade trees, growing wind screens, close planting, and
the addition of pen manure or a heavy vegetable mulch to the soil.
When such requirements are neglected, die-back is likely to appear
even in the absence of Diplodia, and die-back can usuaily be treated
by purely cultural methods, directed to remedying soil, drainage,
and other defects of the kind. A condition resembling die-back
may also be present in trees suffering from Rosellinia root disease.

Another trouble in which Diplodia often plays a secondary réle
is black pod rot and canker due to Phytophthora faberi, a fungus
found in all cacao-growing countries, and of great importance to
the industry of Trinidad, where the loss from this cause has been
estimated as varying from 30 to 60 per cent. of the ripe pods, while
young pods are also heavily affected. As spraying is out of the
question at present in Trinidad, owing to local conditions, the author
recommends efficient soil drainage and reduction of shade trees
to the minimum required, where they cannot be dispensed with
altogether or replaced by marginal wind-breaks. The pruning of
the cacao trees themselves to ensure adequate aeration is recom-
mended, and also the removal and disposal of all diseased pods.
In treating canker the author does not favour deep excision and
recommends instead the removal of the outer layer of the bark to
enable the patch to dry out. Dressings which prevent the drying
should be avoided.

The algal disease [Cephalewros virescens| produces effects some-
what resembling die-back, especially on young trees before they are
fully established or when planted in poor soils or exposed positions.
The affection disappears with the provision of adequate shelter and
the improvement of the soil. A minor disease is thread blight which
develops only under conditions of excessive humidity.

The root disease caused by Rosellinia [R. bunodes and R. pepo
have been recorded] occurs in several districts in Trinidad. In new
clearings it spreads to living trees from certain kinds of forest
stumps. In older plantations it usually occurs where forest material
is deposited by flooded streams. It is a slow working disease
caused by a fungus that grows in damp, sheltered situations on
wood or other vegetable matter in or on the soil. The remedial
measures recommended are chessboard trenching carried below the
level of the lateral roots, in order to check extension of the mycelium
which can spread through shaded soil rich in organic matter and
also along the roots of the trees; the prompt removal and incinera-
tion of affected trees with as many of their roots as possible; and
the proper cleansing of the surface of the soil and aeration of the
deeper layers before replanting.

MAUBLANC (A.). La pourriture brune du Cacaoyer. [Cacao brown
rot. |—L’ Agronomie Coloniale, vi, 54, pp- 177-183, 2 pl., 1922.
The author gives a summary of the present state of knowledge
of cacao brown rot (Phytophthora faberi) which, he states, is one of
the most serious diseases amongst tropical cultures, Navel has

112

reported a case in San Thomé in which 90 per cent. of a particularly
fine crop was rendered worthless by brown rot. The author does
not believe that the oospores of the fungus have been seen, the
bodies taken for these being really chlamydospores. These ger-
minate in a manner similar to that of the conidia. He states that
the chances of infection could be reduced by the removal of mosses
and lichens growing on the trees, and by pruning the latter so as
to ensure a better access of air and sunlight. Diseased fruits should
be picked and destroyed immediately they are noticed, and infected
material should not be left lying on the ground. Good results have
also been obtained by spraying the trees with copper fungicides
(Bordeaux mixture with an addition of sugar and resin as adhesives).
According to Navel this treatment now forms part of the routine in
many plantations in San Thomé,

Metcuers (L. E.) & PARKER (J. H.), Rust resistance in winter
Wheat varieties.—U.S. Dept. of Agric. Bull. 1046, 29 pp.,
11 pl. (3 col.), 2 figs., 1922.

From 1914 to 1917 field experiments to test the resistance to
black stem rust (Puccinia graminis tritici) of about 100 varieties
and strains of winter wheat were carried out in a nursery at
Manhattan, Kansas. The varieties included the hard red winter.
wheats of the Crimean group, such as Turkey and Kharkov, and
the soft red winter wheats grown in eastern Kansas and elsewhere.
In 1916-17 greenhouse experiments were conducted with the same
varieties. Special methods were devised for the inoculation of the
test plants with uredospores from rust cultures, and these are
described in some detail. By these means severe epidemics of rust
were produced each season, and the percentage of infection probably
represents the maximum intensity of attack under Kansas field
conditions.

With the exception of Kanred, P 1066, and P 1068, all pedigree
strains, the winter wheats proved to be very susceptible to rust.
In 1915 these three resistant strains were heavily rusted (40 to
70 per cent.), presumably owing to the presence in the nursery of
some biologic strain of the fungus which was capable of infecting
them, but in 1916-17 the infection percentages were low (5 to 25 per
cent. as against 95 to 98 per cent. on some of the other varieties).
Some degree of resistance was also exhibited by Kansas No. 2390.
Severe rust attack usually reduces the plumpness of the kernels,
but the grain produced by the three resistant varieties was of good
quality, in contrast to the shrunken kernels of the susceptible
strains grown under the same conditions.

Several varieties of spring wheat gave evidence of resistance,
including Beloturka (C.I. No. 15138), Iumillo (C.I. No. 1736),
Kubanka (C.I. No. 2094), Monad (D-1), and Pentad (D-5), all of
the durum or macaroni group (Triticum durum). A hybrid of
Tumillo x Preston, resembling the durum parent, was also resistant.
The only resistant variety of the common or bread-wheat group
(T. vulgare) was Black Persian. Ghirka Spring was very suscep-
tible. Some degree of resistance was shown by all the strains of
emmer and einkorn.

In the greenhouse tests the plants were investigated at two stages

113

of growth, in the seedling stage and at heading time. The results
agreed on the whole with those of the field trials, except that
Kansas No. 2390 gave no sign of resistance at either stage. The
einkorn strains were also more susceptible in the greenhouse than
in the field. Greenhouse tests alone do not, in the authors’ opinion,
furnish a reliable basis for conclusions as to rust resistance, and
the results of such trials should be combined with those of nursery
experiments in estimating the practical value of any variety.

The reaction of the three resistant varieties, Kanred, P 1066, and
P 1068, to inoculation by the rust parasite differs markedly from that
of other varieties described as resistant. In the latter prominent
flecks are nearly always apparent in eight to twelve days after
inoculation, small uredosori being frequently produced. In the
three varieties above named, however, only the most minute and
inconspicuous flecks are occasionally observed, while uredosori are
entirely absent. Reports from Alabama, California, Illinois, Iowa,
Missouri, Nebraska, New York, Wisconsin, and New South Wales
confirm the results of the Kansas field trials with regard to the
resistance of these three strains, but in Minnesota and South Dakota
they were somewhat severely attacked by rust. The existence of
distinct biologic forms of stem rust greatly complicates the study
of resistance and susceptibility, and renders it probable that the
behaviour of the wheats in question will vary according to the
season and locality. In Alabama, Arkansas, California, Missouri,
North Carolina, North Dakota, Oregon, South Dakota, Tennessee,
Texas, Virginia, Wisconsin, and New South Wales the three resistant
varieties are also resistant to leaf rust (Puccinia triticina). In
the light of present knowledge it appears very probable that this
resistance to leaf rust will be maintained under a wide range of
conditions.

Kanred wheat presents a most unusual number of desirable
agronomic characters, foremost among which are its high yield,
earliness, and resistance to cold. In Kansas it yields from three to
five bushels more per acre than either of the two commonly grown
varieties, Turkey and Kharkov. Kanred is also reputed to equal
the latter in milling and baking qualities. Its introduction into
Oklahoma, Texas, Nebraska, eastern Colorado, and other States
where hard winter wheats are cultivated, is now taking place on
a large scale. Kanred wheat is likeiy to prove of great value as
a parental variety in crosses on account of its resistant qualities,
which are evidently transmitted to wheat hybrids in the same way
as other characters. Several of the crosses already made appear
very promising.

Briton-JoNES (H. R.). The smuts of Millet.— Min. Agric. Egypt
Bull. 18 (Botanical section), 6 pp., 3 pl., 1922.

In this paper is given a short description of the three types of
smut which attack sorghum (Andropogon sorghum) in Egypt, viz. :
long smut (Tolyposporium filiferum Busse), head smut (Ustilago
-veiliana Kuehn), and grain smut [Sphacelotheca sorghi (Lk) Clin-
ton]. Of these the first is the most common, and can be found in
almost every crop of millet throughout the country, but the damage
done by it is inconsiderable owing to the low percentage of heads

Cc 3

114

(rarely up to 2 per cent.) and individual grains (about 15 per head)
attacked. The fungus, when young, is eaten by the fellaheen
in some provinces, and is said to have a peculiar sweet taste;
whether it has any effect on the health of the consumer, if taken
in large quantities, is not known. Head smut is of rare occurrence
in Egypt, and the loss caused by it is negligible, as is also that due
to grain smut, although the latter is somewhat more frequent.

The life-history of Tolyposporium filiferwm is not known, and
the only recommendations that can be given for its prevention are
to obtain seed from a healthy crop, to remove and burn the spore-
sacs when young, and for a few years not to grow sorghum on land
that has had a smutted crop. Disinfection of the seed had no
effect on this smut in the author’s tests, but prevented grain smut.
Special treatment against head smut is said to be unnecessary at
“present.

Hecke (L.). Ueber Mutterkornkultur. [The cultivation of Ergot. |—
Nachrichten deutsch. Landwirtschaftsgesellsch. Oesterreich, ii,
(N.F. 6), pp. 119-122, 1922. [Abs. in Zentralbl. fiir Agri-
kulturchemie, li, 9, pp. 240-242, 1922.]

The toxic properties of ergot—due to ergotin, histamin, cornutin,
sphacelic acid, &c.—are stated to fluctuate according to origin, year,
and method of preservation of the sclerotia. The latter are best
preserved in lime. The writer describes experiments in the cultiva-
tion of ergot for medicinal purposes on its natural hosts.

Marchfeld rye was grown in pots and over some of the flowering
ears test-tubes containing ripe ascigerous fructifications, resting on
damp soil, were placed. The escaping ascospores infected the opening
flowers, and a week after the removal of the tubes honeydew was
formed in large quantities. The honeydew containing conidia was
removed by means of small, dry strips of paper and collected in flat
dishes. The drops should be allowed to dry on blotting-paper, as
they will otherwise ferment. Conidia can also be obtained by
growing the Sphacelia stage in pure culture in the laboratory on
suitable media. By means of a sprayer of the type used in vine-
yards, water containing a suspension of the Sphacelza spores is then
sprayed on the ears of a suitable variety of rye during the flowering
stage. The process should be repeated for six consecutive days on
account of the varying time of maturity of the flowers.

Practical experiments only can determine the commercial value
of artificial infection on the lines indicated. In one instance
Schlanstedt rye produced 284 kg. of ergot per hect., an average of
three sclerotia per ear. The price of medicinal ergot has risen
enormously, and this may render its cultivation profitable.

De Montcavtt (P.). L’Ergot du Blé. [Ergot of Wheat.]|—Journ.
Agric. Prat., xxxvi, 34, p. 169, 1922.

The occurrence of ergot [Clauviceps purpwrea] on wheat, usually
regarded as quite exceptional, has been frequent among the French
crops during 1922, especially in the province of Ain. The abrupt
alternations of early heat, rain, and cold are thought to have induced
an unusually open condition of the glumes, so that the enclosed
florets were more accessible to the attacks of the fungus. The

115

disease was particularly severe on imported Swiss varieties. In
view of the high degree of toxicity of the fungus it is very neces-
sary to cleanse contaminated grain by immersing it in water and
skimming off all the infected grains, which rise to the surface.

STAGER (R.). Beitrag zur Verbreitungsbiologie der Claviceps-
Sklerotien. [Contribution to the biology of dissemination of
Claviceps sclerotia.|—Centralbl. fiir Bakt., Ab. 2, lvi, 14-16,
pp. 329-339, 2 figs., 1922.

It is generally assumed that the sclerotia of Claviceps on reaching
maturity fall to the ground close to their host and lie there till the
spring, when they germinate and give rise to stromata bearing
perithecia and ascospores. The ascospores are then disseminated
by means of the wind or of insects. In certain cases, such as that of
ergot of rye, this is undoubtedly what occurs. A study of Claviceps
sclerotia from wild grasses, however, shows that the fungus is not
solely dependent on the wind or insect dissemination of its spores,
but is also transported in the resting mycelium or sclerotium stage.
There are two methods of securing this end. Either the sclerotium
makes use of its host’s contrivances for dissemination, or it is itself
provided with such adaptations.

The author's observations and experiments deal with both alterna-
tives. Two cases are described in which the sclerotium utilizes the
host’s contrivances for dissemination. Brachypodium sylvaticum
has an oval caryopsis enclosed within the paleae. The inferior
palea has at its apex a hook-shaped or sinuous awn, 1-5 em. in
length. This awn, with the caryopsis, easily attaches itself to
passing persons or animals. The crescent-shaped sclerotium, which
is surrounded by the paleae at the base, is taken up and transported
in the same manner. In Calamagrostis epigeios (a new host) the
sclerotia are 2 to 4mm. long, 4 to 4 mm. thick, rod-shaped, and
twisted. They are partially enclosed in and adhere to the lancet-
shaped paleae. At the base of these paleae is a circle of fine hairs
which often exceed the sclerotia in length. In dry weather this
ring of hairs expands like an umbrella, and the paleae and sclerotium
are carried away with great ease by the wind. It is probable that
the autumn gales. could carry them for a distance of several miles.
A similar process probably occurs in Melica ciliata and Phragmites
communis.

Only one adaptation of the sclerotium itself which aids dis-
semination is described. ‘Experiments with Claviceps wilsoni Cke
on the aquatic grass Glyceria fluitans showed that the sclerotia of
this species float in water. Further tests, particulars of which are
given, showed that the sclerotia occurring on the various grasses
may be divided into floaters and non-floaters, and that this is
correlated with their requirements. Thus the sclerotia of Glyceria
fluitans, Molinia coerulea, Phragmites communis, and Phalaris
arundinacea, all of which grow in or near water or bogs, can float
and are not injured by long immersion, while those occurring on
rye, Loliwm, Brachypodium sylvaticum, Sesleria coerulea, Arrhena-
therwm elatius, Agropyrum repens, Alopecurus myosuroides, and
other land grasses sink in water. The floating capacity of the

116

former group appears to be due solely to the air enclosed in the
tissue of the sclerotium, as when this is removed they sink.

In 1899 the author showed that the ergot of Phalaris arundi-
nacea was identical with that of rye, Claviceps purpurea Tul. The
only modification undergone by the fungus on Phalaris is biological,
the floating habit having been acquired to suit the new surround-
ings. This important alteration justifies in the author's opinion the
creation of the new form Claviceps purpurea f. biologica natans
Phalaris arundinaceae.

The sclerotia of certain land grasses (Dactylis glomerata, Holcus
mollis, H. lanatus, Poa annua, and P. nemoralis) form an inter-
mediate group between the floaters and non-floaters. Thus, in tests
carried out near Berne, 69 per cent. of the sclerotia of Dactylis
glomerata, 40-4 per cent. of the sclerotia of Poa nemoralis, 60 per
cent. of the Holeus sclerotia, and most of those on Pod annua,
floated. Possibly the sclerotia on these grasses, like those of
Calamagrostis epigeios, are primarily disseminated by the wind,
but when they are freed from the paleae they can float to a greater
or lesser degree. In Phragmites communis there is little doubt
that both methods are made use of.

PETHYBRIDGE (G. H.), Larrerty (H. A.), & Ruynenart (J. G.).
Investigations on Flax diseases. (Third Report.)—Reprinted
from Journ. Dept. of Agric. and Techn. Inst. Ireland, xxii, 2,
20 pp., 11 figs., 1922.

This report continues the investigations on flax diseases from
previous years [see this Review, i, p. 173}.

The dry weather of 1921 tended to suppress the growth and
spread of parasitic fungi, especially during the drought of the early
part of the summer. Investigations of seedling diseases were there-
fore necessarily limited in their scope. Thus only three reports
were received of seedling blight (Colletotrichum linicolum Pethybr.
& Laff.). In the absence of rain the conidia were not washed from
the cotyledons to the stems, so that lesions on the latter were
uncommon. The lateral spread of the disease from one plant to the
next was also inhibited by the drought.

‘ Browning’ and ‘stem-break’, both due to Polyspora lini Laff.
{see this Review, i, p. 176], caused little damage, as they only
appeared late in the season when most of the crops had been
harvested. As infection starts at the base and proceeds upwards,
an experiment was conducted to ascertain whether the flax flea-
beetle (Longitarsus parvulus) could carry the conidia from a lower
toa higher leaf. The result showed that the insects can carry the
disease, presumably by mechanical transfer of the conidia, to the
leaves near the apex from diseased cotyledons near the soil. Once
established on the upper leaves the spread of the disease to adjoining
plants is assured by direct contact or other means.

The disinfection of flax seed has hitherto been complicated by the
fact that the wetted seeds adhere together owing to the outer wall
of the epidermis of the seed coat becoming mucilaginous when
moist. It was shown, however, by recent trials that this does not
take place to any extent, nor is germination reduced, when the seed
is steeped from one to five hours in one to ten per cent. aqueous

Rhy

solutions of copper sulphate. On removal from the steep the seeds
should be mixed with dry, freshly slaked lime, which, reacting with
the copper sulphate, forms a ‘ Bordeaux’ precipitate on each seed.
The addition of a small quantity of 40 per cent. formaldehyde to
the copper sulphate was also found to be harmless. As a result of
these preliminary tests, a series of experiments on flax seed,
naturally infected with P. lini, was carried out with varying pro-
portions of copper sulphate and formaldehyde, separately and
together. The germination of the seed was somewhat impaired by
the use of formaldehyde alone, applied either by steeping for ten
minutes in 0-1 or 0-2 per cent. formaldehyde or by spraying with
0-5 per cent. formaldehyde so as just to wet the seeds without
causing them to become mucilaginous. No injury resulted when
0-2 per cent. formaldehyde was used in conjunction with copper
sulphate (steeped for one hour), the latter apparently rendering the
seed coat more or less impermeable. Neither seed treatment nor
spraying the plants with a 2 per cent. Bordeaux mixture proved
effectual in eliminating the disease and subsequent spread led to
the treated plots becoming as severely infected at the end of the
season as the controls.

Previous tests had shown that the resting or teleutospores of
Melampsora lini, which cause the black ‘fired’ areas on flax stems,
could, under certain conditions, remain viable from the autumn of
one year to the spring of the next. During the summer of 1921
evidence was obtained that the teleutospores can retain their vitality
for an even longer period, ‘fired’ material harvested in 1919 and
subsequently stored indoors having successfully infected pots of
healthy flax seedlings on which it was spread in the spring of 1921.
It is improbable, however, that even under excessively dry con-
ditions, the teleutospores could survive for seven years, the period
allowed in Ireland to elapse between successive crops of flax in any
given field. The various attempts of the authors and other workers
to transmit the strain of this rust commonly found on Linwm
catharticum to cultivated flax have given negative results, and it is
now regarded as certain that the two are distinct biologic species.
Uredospores of M. lini from cultivated flax inoculated on L.
angustifolium caused only slight infection.

Root rot (Lhielavia basicola) occurred sporadically in one crop.
The plants were pale green and stunted in appearance, owing to
malnutrition resulting from a diseased condition of the roots, the
whole root system being involved in some cases, while in others
only the youngest portions were affected. Microscopic examination
revealed the presence of the chlamydospores and conidia of the
fungus and inoculation experiments proved its pathogenicity to
flax. It was found that two common weeds, groundsel (Senecio
vulgaris) and goosefoot (Chenopodium albwm), also acted as hosts
of 7. basicola, the latter being specially susceptible. The eradi-
cation of these and other susceptible weeds and the cultivation of
two successive root crops previous to flax would probably leave the
soil comparatively healthy.

‘Flax Droop’ is the name proposed for an apparently non-
parasitic disease of the taller pure line varieties observed for the
first time in 1921. The first symptoms were noticed on 10th July,

118

when the plants presented a prematurely ripe appearance. The
upper portions were light green in colour and drooped considerably,
though actual wilting was not observed. The upper parts of the
stalks were soft and herbaceous, but the base and the excessively
numerous lateral branches arising below the affected part were
normal. About flowering time, and before the development of the
seed-bolls, the tops of the affected plants turned yellow, bent over
still more, and eventually died. An examination of the roots and
stems for the presence of parasites gave negative results. In plants
but recently affected the fibre elements of the vascular bundles on
the upper or convex side of the drooping stem appeared partially
dissolved, while those on the lower or concave side were still
normal. At a later stage this condition became general around the
vascular ring, and when the upper part of the stem was dead only
a trace of cellulose thickening was visible in the fibres. The
middle lamellae remained, though in a discoloured and disorganized
condition. The immediate cause of ‘droop’, therefore, is a weaken-
ing of the fibres in the affected regions. but the origin of this
degeneration is at present obscure. The excessive dryness of the
soil in which the diseased plants were growing was not suffi-
cient to account for it. Copious watering did not effect a cure, and
dry conditions tend to promote the thickening, rather than the
reverse, of the mechanical elements of plants. The value of the
varieties in question, which depends largely on their length of
stem, would be seriously diminished if this trouble were to become
at all general. Seed has been saved in order to ascertain whether
the disturbance is due to an inherited character of the varieties.

The fungus causing the Sclerotiwm disease of flax was definitely
identified as Sclerotinia libertiana, a parasite which is perhaps best
known in Ireland, under the name Sclerotinia sclerotiorum Massee,
as the cause of the ‘stalk disease’ of potatoes. A healthy potato
plant inoculated with a pure culture of the fungus from flax rapidly
developed the typical symptoms of stalk disease. The latter has
been observed at times in the North of Ireland, and its ability to
spread to flax is of considerable interest.

SCHILLING (E.). Beobachtungen iiber eine durch Gloeosporium
lini verursachte Flachskrankheit in Deutschland. {Observa-
tions on a disease of Flax in Germany catlsed by Gloeosporiwm
lint. |—Faserforschung, ii, 2, pp. 87-118, 13 figs., 1922.

During 1920 and 1921 the flax disease which has been variously
termed seedling blight, anthracnose, and canker by different investi-
gators was observed near Sorau, this being its first recorded
appearance in Germany. It is caused by the fungus Gloeosporium
[Colletotrichum] lini, with which, in the author's opinion, Pethy-
bridge’s and Lafferty’s subsequently described Colletotrichwm lini-
colum is identical [see this Review, i, p. 173].

The symptoms of the disease are described at some length and
stated to agree in the main with the accounts of Bolley, Pethy-
bridge, and Miss Westerdijk. The last-named, however, reports
a spotting of the leaves, stalks, and capsules of older plants which
has so far not been observed in Germany, while the exposure of the
woody portion of the base of the stem, due to the dissolution of the

119

tissues in advanced stages of the disease, as described by Pethy-
bridge, was not specially noticeable in the German cases.

The fungus was isolated and grown iu pure culture. Setae were
not invariably present in the acervuli, their development apparently
coinciding with dryness of the surrounding atmosphere. Judged by
this criterion, the author thinks that the separation of the genera
Colletotrichum and Gloeosporiwm cannot be maintained. Conclusive
evidence was obtained that the disease is transmitted by the seed,
_by means of mycelium on the testa. Infection by spores direct
from plant to plant or from the soil also occurs. In the author's
experiments, all the varieties of flax and linseed tested were sus-
ceptible, but the conditions of the experiments were exceptionally
favourable to infection, and under natural conditions in the field
the disease was limited to Bombay and Sicilian linseed, Finnish
fibre flax, Russian crown flax, and a Silesian fibre flax.

The disease causes a serious reduction of germination and some-
times a heavy loss of crop. It may best be prevented by the use of
clean seed. The effects of climatic. conditions, methods of ecultiva-
tion, and the like have not yet been sufficiently studied to allow of
any recommendations of practical value being made in regard to
them. It has been observed that the plants succumb to the disease
more readily in dry than in damp weather, but that the parasite is
more readily disseminated during the latter. The control measures
advocated by previous workers on this disease are discussed, and
although the author does not appear to have tested them, he is of
opinion that such measures could only be applied on a large scale
with great difficulty and expense, and that the use of clean seed is
the most essential requirement.

Lacey (MARGARET S.). Studies in bacteriosis. WI, Bacillus caro-
tovorus as the cause of soft rot in cultivated Violets.—Avnvn.
of Appl. Biol., ix, 2, pp. 169-170, 1922.

This is an account of the occurrence in England, early in 1921,
of a destructive disease of cultivated violets caused by Bacillus
carotovorus. The plants examined had the whole interior of the
stem reduced to a soft white mush, the rot spreading to the petioles
and causing the leaves to fall. The organism was isolated and
identified by comparison with authentic cultures of B. carotovorus.
Inoculations reproduced the disease in violets and also caused the
characteristic white rot of carrots, turnips, potatoes, and onions.

Caborer (A.), L’Abricotier dans la Vallée du Rhone. [The
Apricot in the Rhone Valley.|—Journ. Agric. Prat., lxxxvi, 39,
p- 271, 1922.

For the last thirty years a gummosis of apricot trees, accom-
panied by the attacks of a hitherto unidentified parasite, has been
known in the alluvial soil of the Rhone Valley [see this Review, i,
pp. 180 and 385]. The writer had opportunities for studying it,
while stationed at Tournon (Ardéche) from 1901 to 1913. The
damage is particularly severe between Lyons and Peyraud, and
between Lyons and Saint-Rambert. The disease is practically non-
existent on the dry soils of the hill-sides on the left bank of the
river, and from the vicinity of Avignon as far as Tarascon.

120

The average duration of the disease is two to three years, though
it may be fatal within a year in localities exposed to frequent
floods. Older trees are uniformly more susceptible to the disease
than young ones. During the first year of the attack the trees
often present a curious appearance, some portions being healthy
and others withered. The following year the withering is complete.
It has been observed that the disease is most prevalent in orchards
formerly used for the cultivation of mulberries. Cherry trees in
excessively wet or dry soils exhibit somewhat similar symptoms.
Isolated cases of the withering of apricots in schistose soils have
been reported from St. Jean-de-Maurienne (Savoy), where the
symptoms appear to be identical with those in the Rhone Valley.

The writer believes that thé withering is due to a fungus or
bacterium which invades the roots and wood of the stems, or the
latter only, and is accompanied by gummosis. As practical measures
to reduce loss he recommends that plum trees should not be used as
stocks, unless they are planted level with the soil, the roots being
covered with a mound, at least 1m. in width by 0-50 m. in height.
The same planting in mounds is advisable with all apricots grown
in localities subject to imundation or where the disease is already
present. Apricot orchards should be opened, when possible, only in
new soil,

Harrison (T. H.). Note on the occurrence in New South Wales,
Australia, of the perfect stage of a Sclerotinia causing brown
rot of fruits.—Journ. & Proc. R. Soc. of New South Wales,
lv, pp. 215-219, 1 pl., 1922.

In September, 1921, following a season of heavy brown rot
intestation of orchard trees in New South Wales, the author found
two apothecia of a Sclerotinia arising from mummified apricots in
an orchard near Sydney. Tissue cultures from one of these on
potato dextrose agar gave rise to a typical Monilia growth, and
inoculation of loquat [#riobotrya japonica] and apple fruits with
conidia from a pure culture caused typical brown rot lesions.
Further studies are in progress, but there are already definite
indications that the organism is Sclerotinia fructigena and a distinct
biologic form from both the European and American forms. The
ascigerous stage of this fungus has not been previously recorded in
Australia.

NORDMANN. Der Apfelmehltau und seine Bekampfung. [Apple
mildew and its control.|—Deutsche Obstbawzeit., |xviii, 21-22,
pp. 202-203, 1922.

Apple mildew [ Podosphaera leucotricha] is stated to be assuming
such serious dimensions all over Germany, and more especially in
the south, where the summer months are often very dry, that it can
only be checked by an organized campaign. One of the chief pre-
ventive measures is the selection of resistant varieties for planting,
e.g. Charlamowsky, Queen, Winter Golden Pearmain, Lane’s Prince
Albert, &. The cultivation of the two extremely susceptible
varieties, Landsberger Renette and Cox’s Orange, should be discon-
tinued. The American variety Baldwin is the only one known to
be wholly immune against mildew in Germany. Drastic and regular

i
;
,

121

pruning is another very effective means of control, the destruction
of affected shoots in the summer being particularly important. Of
the various fungicides those containing sulphur are chiefly recom-
mended, excellent results having been obtained with solbar and in
some cases with colloidal sulphur [see this Review, i, pp, 228 and
390]. Dusts are, however, considered to be preferable to sprays,
and the new preparation ‘elosal’ is stated to, be extremely
effective.

CUNNINGHAM (G. H.). Apple and Pear black-spot: their appear-
ance, cause and control.—New Zealand Journ. of Agric.,
xxv, l, pp. 20-81, 11 figs., 1922.

The symptoms of black spot [scab] of apple (Venturia inaequalis)
and pear (V. purina) are described and figured. The former is
prevalent and is the most serious apple disease throughout New
Zealand except in localities where the humidity is low during the
growing season, such as Central Otago and certain districts im
Marlborough and North Auckland. In New Zealand the ascigerous
stage of the fungus develops in the ‘spring’ (August and September)
from mycelium which has ‘overwintered’ in dead leaves: This
stage is found only in the tissues of dead leaves, not on fruits or
shoots. ;

Pear black spot differs from the foregoing in forming conidia
freely on young shoots and laterals, sometimes continuously for as
long a period as nine months, and it is almost certain that shoot
infection is one of the means of carrying the organism over the
winter. Perithecia are also produced abundantly on the fallen
leaves, and the ascospores so formed are capable of infecting the
new leaves and fruits in the spring.

In an appended note on the control of black spot, written by
J. A. Campbell, it is pointed out that control by the destruction of
infected leaves alone is impracticable, not only on account of the
difficulty of ploughing in all the leaves, but also because of the
danger from infected shoots. It is, however, advisable to plough
deeply in the autumn, in order to bury as many leaves as _ possible
and thereby minimize infection by reducing the number of asco-
spores. A series of spray applications is necessary to cover the
danger period of ascospore infection and to destroy the conidia on
shoots and prevent their subsequent development on leaves and
fruits. The following schedule has been found to control the
disease effectively in Auckland, Hastings, and Nelson, and is
accordingly recommended to fruit growers. (1) Green-tip stage | pre-
pinking or spur-bursting stage], 54-50 Bordeaux or 1-10 lime-sul-
phur, (2) between open-cluster and pink stage, 3-4-50 Bordeaux or
1-30 lime-sulphur ; (3) calyx-spray (petal-fall), 1-100 to 1-120 lime-
sulphur ; (4) ten days later, 1-100 to 1-120 lime-sulphur; (5) every
month until maturity, 1-100 to 1-120 lime-sulphur; (6) immedi-
ately before picking, 1-100 lime sulphur. The object of the last
spray is to prevent storage infection, and it may’ be applied with
advantage when the fruit is destined for export. Arsenate of lead
may be added to the third and subsequent sprays for the simul-
taneous control of the codling moth and leaf-roll caterpillar. The
period covered by the applications, and the thoroughness with which

122

they are given are stated to be more important factors in the con-
trol of the disease than the exact strength of the sprays.

Curtis (K. M.). Ascospore ejection of the Apple and Pear black-
spot fangi.— New Zealand Journ. of Sci. and Tech., v, 2,
pp. 83-90, 1922.

A series of experiments has been carried out to determine the
duration of the period of discharge of ascospores from the peri-
thecia of Ventwria inaequalis and V. pirina, the fungi responsible
for the black spot [scab] of apple and pear respectively. Five
apple and three pear leaves were examined daily from 14th September
to 20th December, 1921. It was found that ascospore ejection began
on 14th September, reached its maximum on and immediately after
2nd October, ceased to be of practical significance by 31st October,
and stopped entirely by 12th December. The season’s discharge from
both pear and apple leaves fell into several distinct periods. There
was one period of maximum discharge, which occurred early in the
season, five subsidiary periods of lesser importance, but still of
practical significance, and several of negligible dimensions. The
maximum output of spores for any one wet period occurred between
2nd and 11th October, in the case of all the leaves, both pear and
apple. In the majority of the leaves the maximum average daily
output for any wet period and the maximum single day’s output
for the season also occurred during this period. The output of
spores from pear leaves, as compared with those of apple, is marked
by a greater total number of spores ejected during the season, and
a more uniform daily ejection which lasted over more protracted
periods. 5

In another experiment four apple leaves were kept without
water from 14th September to 6th December, during which time
the majority of the perithecia passed through a very sensitive
phase, that of the delimitation of the ascospores within the asci.
This did not, however, prevent an appreciable ejection of ascospores
when the drought was broken, although in normal leaves ejections
of any magnitude had ceased for a month or six weeks before that
time.

The usual system of cultivation followed in the orchards tends
to bring to the surface a certain proportion of the leaves which
have been ploughed in. If this oceurs within six to eight weeks
after the maturation of the perithecia, the latter will become a
direct source of danger as soon as the rain begins. The leaves
shee therefore be destroyed by fire after they have fallen from
the trees.

JARVIS (H.). Fruit fly investigations.—(Queensland Agric. Journ.,
Xvill, 4, pp. 269-271, 1922.

In this report is included a section on plant pathology, containing
notes by H. Tryon on certain diseases of deciduous fruit trees in
the Granite Belt-district of Queensland. The apple bark canker or
bark blister caused by Coniothecitum chromatosporwm is stated to be
prevalent all through the district and to attack also the pear. It
causes the formation of dark areas in the outer bark, the cells being
replaced by masses of closely packed, short-celled mycelium. The

123

segments of the mycelium ultimately become transformed into
spores. A second stage with pycnidia of the Phoma type is also
stated to occur. The attack results in a die-back disease of the
twigs and may even kill fairly large branches. Seriously diseased
branches should be cut out and the rest of the tree treated with
Bordeaux mixture or lime-sulphur.

A second bark canker of the apple in this district is caused by
the fungus Gloeosporiwm malicorticis which is also responsible for
the bitter rot on the fruit. A short account of the disease is given
and, the same treatment is recommended as in the other case,
with the addition that all rotting fruit should be removed and
destroyed.

WatTERs (R.). Cool storage of Apples. An investigation of flesh-
collapse.— New Zealand Jour. of Agric., xxv, 1, pp. 34-89,
1922.

Fruit kept in cool storage is liable to deterioration from a num-
ber of causes, which must be carefully distinguished in order to
improve the methods of preservation.

Black spot [scab] of apples (Venturia inaequalis) undoubtedly
continues to develop to some extent in cool storage, and judging by
the very early stages of infection that are found, it is clear that
it can also spread to sound fruit in spite of the very low tempera-
ture. In this case the remedy must obviously be applied before
picking.

The disease known as ‘sting’ refers, strictly speaking, only to
the injury succeeding insect punctures. Popularly, however, sting
is a form of rot, caused directly by blue mould (Penicillium), bitter
rot (Glomerella), or Botrytis, following some form of mechanical
injury to the skin. Thus, the origin of this trouble is also to be
sought before the arrival of the fruit at the store.

A third type of disease, known as scald, appears in the form of
irregular, dark, sunken patches in the surface of the apple, and is
caused by vapours or esters given off by the fruit. Scald is most
severe among apples packed in barrels, and may be prevented by
satisfactory ventilation or wrapping the fruit in oiled paper.

The cause of flesh-collapse, which is probably identical with the
‘brown-heart’ recently reported as occurring in shipments of
Tasmanian and Australian apples to England [see next abstract]
has not yet been definitely ascertained. The skin remains intact
until the last stage of the disease, while part, or the whole of the
interior may be in a state of collapse. Affected apples are springy
to the touch. Fungous rots may set in and cause a discoloration
of the skin. This disease has already been responsible for extensive
losses, and the success of the apple export trade is largely dependent
on its prevention.

Various causes have been suggested to account for flesh-collapse,
such as drought followed by excessive rain, lack of cultivation,
varying degrees of maturity of the fruit, age of the trees, and lapse
of time between packing and delivery. Investigation has shown,
however, that none of these reasons can be considered adequate, the
disease occurring under the most varied conditions. The writer
believes that individual apples, even of the same variety, differ

124

considerably on reaching the store in their degree of resistance to
flesh-collapse.

In order to test the effects of varying temperatures, a number of
Sturmer apples of different lines were subjected to alternating
temperatures ranging between 20° and 60° F. No sign of flesh-
collapse developed in any of the fruit. Various other attempts at
the artificial production of the disease by fluctuating temperatures
and other means were unsuccessful. Both in 1920 and 1921 flesh-
collapse appeared in September, after the fruit had been in storage
for three or four months. The general standard of temperature
adopted in the stores was 32°, but there were considerable differences
in the time during which the machinery was kept running.

The writer’s hypothesis, upon which he is basing his present
investigations, is that the flesh of the apple both cools and warms
up more slowly than the atmosphere of the store, thus averaging
out the varying temperature of the chamber. Some stores keep
the refrigerating machinery running continuously so that the store
remains for the whole twenty-four hours at 32°, while in others it
is only kept running for eight hours, the insulation being relied on
for the remainder of the day, and in these the average temperature
of the apples will be above 32°. Prolonged exposure to a tempera-
ture of 32°, which is known to produce a peculiar physical action
on water, might exert some strain on the flesh and consequently
cause injury. On board ship and in stores where the machinery
runs for long periods, abundant flesh-collapse occurs.

Two important lines of inquiry present themselves as a result of
these observations; first, the investigation of the optimum tempera-
tures for the storage of New Zealand apples, and second, the means
of increasing the resistance of the fruit to cool storage conditions.

Brown Heart.—Fruit, Flower, wnd Vegetable Trades’ Journ.,
xii, 17, p. 455, 1922.

Correspondence between the Agent-General for Tasmania, the
Managing Director of the Fruit and Produce Exchange of Great
Britain, and Dr. Charles Brooks of the Bureau of Plant Industry,
Washington, on the subject of brown heart of apples, is reproduced
in full.

A conference of shippers, growers, and others interested in the
Australian business was recently called to consider the best means
of dealing with brown heart, a disease of apples somewhat similar
to apple scald, which has been prevalent in shipments during the
last few years. Dr. Brooks states that brown heart is largely due
to the accumulation of carbon dioxide given off by the apples, being
also favoured by high storage temperatures and over-ripeness at
picking-time. Though similar to mternal breakdown |see last
abstract] brown heart is a distinct disease, while it is totally
different from scald, which is primarily a skin disease and can be
controlled by the use of oiled wrappers. The removal of foul air
from the boat chambers would largely prevent brown heart, while
pre-cooling is also very advisable. The latter process, however, can
be dispensed with if adequate refrigeration and ventilation are
ensured. The ships should carry self-registering thermometers, and
a temperature of 30° to 34° F. should be maintained. Under present

125

shipping conditions it is dangerous to open up the storage chamber
once it has been closed, the addition of fresh cargo causing a rise in
the temperature of the fruit already cooled. During the period
elapsing between the removal of the fruit from the ship and its
arrival at the place of destination, it should also be kept at a low
temperature.

SwincLe (D. B.). Pear and Apple blight in Montana.— Better
Fruit, xvi, 12, pp. 12-13, 18-19, 1922.

Fireblight [Bacillus amylovorus|, which attacks apples, pears,
and quinces severely, and stone fruit and pomaceous shrubs mildly,
is extremely widespread in Montana. The disease, the characters
of which are described in detail, is most virulent on rapidly grow-
ing, vigorous trees, the damage done to slow-growing trees being
comparatively slight.

Amongst apple varieties, Duchess of Oldenburg, Gano, Ben Davis,
Rome Beauty, Wagener, Stayman, Winesap, and Thomkins King
are relatively resistant; McIntosh Red, Jonathan, Delaware Red,
Grimes Golden, Wealthy, Baldwin, and Northwest Greening are
moderately resistant; Yellow Transparent, Fameuse (Snow) Spitz-
enberg, Delicious, Whitney crab, Martha crab, and Hyslop crab are
moderately susceptible; Alexander, Wolf River, Transcendent crab,
McMahon, and Winter Banana, are very susceptible.

Of pear varieties, Kieffer, Flemish Beauty, and Beurré d’Anjou
are moderately resistant; Bartlett moderately susceptible; and
Clapp’s Favourite extremely susceptible. It is recommended in
grafting to use the Chinese sand pear (often called ‘ Japanese’) as
a stock, and Kieffer or some other resistant variety as a scion.

MILBRATH (D.G.). Résumé of Pear blight history and methods of
control.— Monthly Bull. Dept. Agric. California, xi, 10, pp. 760-
765, 1922.

Fireblight of pears (Bacillus amylovorus) was widespread and
serious in California during 1922, especially in the Sacramento
Valley and the adjoining foot-hills. Its occurrence in the coastal
regions, and in the San Joaquin and Antelope Valleys, was sporadic.
In other States also pear blight was very severe in 1922, the
damage in New Jersey being probably heavier than ever before.
The disease was reported to be prevalent in Michigan, Montana,
Arizona, New York, Ohio, Missouri, South Dakota, and Washing-
ton. The direct losses from the disease in California may be
estimated at 5 to 10 per cent. of the crop, in addition to the
indirect loss due to heavy expenditure on control measures, and
to a set-back in the growth of the trees as a result of drastic
pruning.

An account is given of the symptoms of the disease, plants liable
to infection, and methods of dissemination. It is stated that the
practice of bee-keeping, recently taken up by orchardists in certain
districts of Washington, has greatly increased the severity of the
disease.

Pear blight can be largely controlled by the use of resistant root
stocks, e.g. Pyrus ussuriensis. The possibilities of infection may
be reduced to a minimum by high budding, successfully practised

126

in Grass Valley with the susceptible Bartlett variety on ussuriensis
root stocks. Seckel, Sand, Abraham, and Le Conte are also ex-
tremely susceptible, Kieffer, Duchess, and Winter Nelis slightly less
so, and Douglas, a Kansas variety, comparatively resistant.
Thorough pruning and excision of infected parts is very important.
The most virulent and active bacteria are found on the margins and
advancing points of the cankers, and the bark should be removed
for at least four inches beyond the slightest tinge of discoloration.
Suckers at the foot of the tree readily become infected and should
be cut off as they appear. A solution of mercuric cyanide and
corrosive sublimate (1 oz. of each to 4 galls. of water) is useful for
washing wounds and disinfecting implements.

PuTTERILL (V. A.). Pear scab in the Western Province: experi-
ments and facts relating to its control. Dept. of Agric.
S. Africa, Bull. 2, 31 pp., 12 pls., 1922.

Spraying experiments on experimental orchards at Ida’s Valley, -
Stellenbosch (1920-1921), and at Lourensford Estate, Somerset
West (1921-1922), are described. The results indicate that pear
scab or Fusicladium pirinum (Venturia pirina) can be satis-
factorily controlled by five sprayings with 4-4-50 Bordeaux
mixture, the last three of which are given in combination with
arsenate of lead in order to control the codling moth. This does
not include a dormant spraying with lime-sulphur which is applied
for general hygienic purposes before growth is renewed after the
winter.

The schedule recommended is (1) when the buds are breaking and
leaves just showing; (2) when the blossom buds have opened, but
the individual blossoms are still closed, i.e. about ten days later
than (1); (3) when the last petals are falling, i.e. about ten days
later than (2); (4) ten days to two weeks after (3); (5) five weeks
later. The tests demonstrated the importance of applying the
mixture at least twice between the time that the buds begin to
open and when they are ready for the first spraying against codling
moth. The amount of diseased fruit varied from 2 per cent. in
sprayed trees to 59 per cent. in unsprayed trees, and was always
considerably greater when certain of the sprayings were eliminated
than when the full schedule was given. Of proprietary mixtures
tried, ‘Arboretas’ did not control scab, but ‘Capex’ Bordeaux
mixture made by the Cape Explosives Co., was very successful,
being apparently better than the home made mixture in some cases.
The disease, lithiasis, supposed to be of physiological origin and
occurring abundantly in the localities of the tests, [see this Review, i,
_p. 11], appeared to be almost completely controlled by the
sprayings.

In a note on the occurrence in South Africa of the perithecial
stage of the pear scab fungus, appended to the Bulletin, the author
records the discovery in great abundance of perithecia of Venturia
pirina on the previous season’s leaves of Beurré Bose pears in
September 1921. Newly infected leaves were first found on the
trees in the orchard from which the perithecia were obtained on the
6th October.

127

SranForD (H. R.).—Control of Peach scab.— Monthly Bull. Dept.
Agric. California, xi, 10, pp. 765-774, 5 figs., 1922.

During the last few years peach scab, caused by Cladosporiwm
carpophilum, has been on the increase in southern California.
While it is improbable that the disease will develop in California
to such a severe extent as in the eastern United States, owing to
the more favourable climate of the former, the author considers that
control measures must be adopted to prevent considerable losses.
The present paper deals with the results of investigations during
the summer of 1922 on the prevalence of scab, varietal resistance,
effect on grade and price, and control measures.

Of the varieties of canning peaches examined, Lovell was the
most severely infected and Sims the least; Elberta and Phillips
Cling were fairly free, while Muir and Tuscan varied considerably
in different orchards. Orange and Lemon Clings and Salway are
grown only on a restricted area in California, but those examined
were free from scab.

In the orchard the disease is easily recognized in the late summer
by the oval, brown lesions on the twigs. Towards autumn olive
coloured patches and spots, consisting of mycelium and spores, are
found on the under side of the leaves. The damage to the leaf is
slight, and is important chiefly as affording greater numbers of
spores for twig infection. By midsummer the infected fruit shows
light spots which gradually deepen to dark olive, and may either
remain separate or coalesce. Usually they occur only on the side of
the fruit exposed to moisture, causing a retardation of development
on that side. On late varieties the spots form cork cells, the scaling
off of which has given rise to the name of scab.

_The writer inspected the process of grading Lovell peaches at
a cannery, and ascertained that the amount of scab in the ‘C’ and
‘D’ grades was 8-5 and 6-4 per cent. respectively. On the basis of
these percentages the average result from a ten-acre orchard would
be 10-4 tons of fruit placed in a low grade on account of the fungus.
The corresponding pecuniary loss may be roughly estimated at
$312 on the ten acres.

The life-history of the fungus is described. It overwinters
beneath the surface of the twig, and therefore cannot be reached
by a dormant spray. The fungus and the twig resume growth
simultaneously in the spring, the epidermis of the twig being
ruptured and spores formed in more or less conspicuous tufts on
the surface. The spores are carried by the wind or other agents to
the fruit, which is protected, however, for the first three or four
weeks after setting, by its dense pubescence. After infection takes
place there is an incubation period of forty to sixty days before the
olive coloured spots referred to above begin to show. While the
fruits are being infected new twigs are also attacked, and thus
the life cycle is completed.

Experiments showed that excellent control of the disease could
be secured by spraying with self-boiled lime-sulphur 32-32-200,
One spray was sufficient for early ripening varieties and two for
the later sorts. The fruit must be kept protected against infection
from about a month after blooming until six weeks or.two months
before ripening. In the experiments recorded, the early ripening

128

variety was sprayed on 16th May and the late on 23rd May and
23rd June, excellent control being obtained. The use of commercial
lime-sulphur or Bordeaux mixture is not advisable on account of
the injury to peach foliage caused by these fungicides.

RABBAS. Die Rutenkrankheit der Himbeerstrauche. [The cane
disease of Raspberry bushes. |—Nachrichtenbl. deutsch. Planzen-
schutzdienst, 1, 6, p. 42, 1922.

In 1921 over 70 per cent. of the raspberry crop of an extensive
plantation in Anhalt was destroyed by the cane blight due to
Didymella applanata, and the inspection of a number of other
plantations showed that the disease is more widely distributed than
was previously suspected. It is characterized by the appearance
from the end of June onwards of bluish-brown spots on the fruit-
bearing canes, followed by a longitudinal rupturing of the bark,
which peels off in rings. Owing to the similarity between the
natural colour of the ripening canes and the spots caused by the
fungus, the latter are not easily detected at a later period of
the season. Minute black dots, the perithecia of the fungus, are
scattered all over the loosened bark, and the spores liberated from
these the following spring disseminate the disease. Infected canes
wither before the fruit ripens, sometimes even in the early spring
when the disease is frequently mistaken for frost injury. Many
growers also confuse it with the effects of protracted drought or
with senescence.

Little is known of direct measures of control. Infected canes
must be cut away and burnt, and spraying with 1 per cent. solbar,
1 per cent. formalin, 2 per cent. Bordeaux mixture, 2 per cent. milk
of lime, or 0-05 per cent. colloidal sulphur is provisionally recom-
mended. The first application should be given in the autumn,
when the soil should also be treated with caustic lime (4 to 1 kg.
per sq. m.), and the bushes lightly hilled to prevent the spread of
spores adhering to the stumps. The second application of the
fungicide should be given in the following spring, two or three
weeks before the appearance of the leaves, repeating the process at
intervals of two to three weeks if necessary. The use of fertilizers
containing potash and phosphoric acid is recommended and also
lime, especially where the soil is acid.

Conflicting opinions as to varietal susceptibility appear to be held.
Marlborough is universally recognized as susceptible, while Super-
lative appears to be heavily infected in some plantations and immune
in others. Comparatively resistant varieties are the Harz Jewel,
Kneveth Giant, and Schatfer’s Colossal.

Witcox (R. B.). Eastern blue-stem of the black Raspberry.—
U:S. Dept. of Agric. Cire. 227, 12 pp., 1 pl., 1922.

Eastern blue-stem or curly leaf, a disease which does not corre-
spond with any previously described, is responsible for severe losses
in a number of regions where black raspberries are intensely culti-
vated in Ohio, New York, Michigan, and Wisconsin.

The general effect produced by the disease is a gradual stunting
and reduction of vigour. During the first season of infection the
symptoms may be somewhat inconspicuous, the plants giving a good

129

crop of fruit. The berries, however, are smaller and more brittle
than usual, and the shoots shorter and weaker. The hindrance to
food storage causes a marked reduction, during the second season,
in the size and strength of the plant and in the quality and quantity
of the fruit. By the third spring the canes make only a feeble
growth, if any, and the plants frequently die during the following
summer or winter. The average period elapsing between the first
symptoms of the disease and the death of the canes seems to be two
to three years. Recovery has in no case been observed.

Affected plants show a peculiar curling of the upper leaves,
especially on the young, rapidly growing shoots. The margins and
veins do not arch downwards as in ‘yellows’, but the midribs of
the leaflets are hooked or recurved. A uniform mottling of the
affected leaves, extremely faint and scarcely noticeable in the early
stages and due to the presence of small, scattered, yellowish-green
areas, usually accompanies the disease. In the Dover-Avon district
of Ohio, where these investigations were chiefly carried out, a deep
violet-blue discoloration of the stems of shoots is a constant symptom
of the disease. This discoloration, which is confined to the green
chlorophyll layer of the stem, appears in the form of dots or longi-
tudinal stripes resembling pencil marks, irregularly placed and often
confluent. It occurs commonly at or near soil-level, extends upwards
on the stem to a height of 2 ft. or more, and is also found near the
bases of lateral branches. On fruiting canes of diseased plants the
petioles and stems of lateral branches often show short, narrow,
longitudinal streaks of brown or purplish-brown. In some localities
the blue discoloration, which is of great assistance in the detection
of the disease, is unfortunately altogether absent. No abnormality
of the root system has been observed.

Eastern blue-stem appears to be a strictly systemic disease affecting
all the shoots. It is readily transmitted by planting suckers or
tips from affected plants, even though they may show no symptoms.
Diseased plants cut off at the ground after harvesting throw up
young shoots which soon show typical symptoms. ‘The term ‘eastern
blue-stem ’ is used in order to distinguish the disease here described
from a parasitic disease of black raspberries in Washington, known
locally as ‘blue-stem’. It must also be distinguished from ‘ yellows’,
a term applied to the forms of mosaic and leaf curl diseases described
by Rankin and others [see this Review, i, p. 218; ii, p. 17]. Apart
from symptomatic distinctions, the host-range of eastern blue-stem
differs from that of ‘yellows’, the former attacking only black
raspberries [Rubus occidentalis] and, probably, blackberries, while
the ‘ yellows’ type of leaf cur] affects red raspberries Te idaeus},
‘purple canes’, the Japanese wineberry (R. phoenicolasius), and
two varieties of black raspberry, the Cumberland and Hoosier. Of
the four varieties of black raspberry grown commercially in the
Dover-Avon district, the Hoosier appears to be the most susceptible,
Cumberland and Plum Farmer are also seriously affected, while
Kansas is the most resistant, though no variety has been found to
possess a really high degree of resistance.

The characteristic deformity and mottling of the leaves, the
stunting and gradual death of the plants, and the transmission of
the disease to vegetative progeny, all indicate that the disturbance

130

is of the mosaic type. Microscopic examination has failed to reveal
the presence of fungi or bacteria, while there is evidence to show
that neither environmental factors nor exhaustion as a result of
protracted vegetative propagation are primarily responsible. Infee-
tion spreads rather slowly to other plants in the field, the means of
dissemination being unknown. All attempts at artificial trans-
mission have given negative results. The disease has been known
to spread over distances of 200 to 300 yards. It has been observed
to spread most rapidly in fields making vigorous growth, coming to
a standstill with the cessation of active development. New infections
are most frequent on tender, succulent plants.

The disease may be controlled to some extent by thorough and
repeated roguing, by the immediate elimination of infected plants
in young fields, and by the planting of disease-free nursery stock at
as great a distance as possible from affected plantations. Selection
experiments have been started with a view to securing resistant
strains of commercial varieties. The application of fungicides
appears to be useless. i

Situ (E. H.) & Puruurps (E. H.). Studies of the so-called ‘smut’
of white Fig varieties. — Monthly Bull. Dept. Agric. California,
x1, 10, pp. 755-758, 3 figs., 1922.

‘Smut’ in dried figs is characterized by the appearance of a black,
powdery mass in the pulp of the fruit, the mass being composed of
spores of the fungus Aspergillus (Steriqgmatocystis) niger. On
squeezing affected fruits, a black cloud of spores is ejected from the
eye end. Badly smutted figs can be picked out by the dark
translucent appearance of the skin, but those slightly affected only
show dark or yellowish spots in the pulp, with no external evi-
dence of disease, and thus may reach the market. The loss is
considerable both from culls and from the inferior quality of the
packed fruit. All the white varieties of figs are affected, Adriaties
perhaps most abundantly.

On green figs the rot is characteristic, starting round the eye
and affecting both the skin and pulp. The tissues become dirty
white to slightly pinkish in colour, remaining at first fairly firm in
texture but later developing a cheesy consistency. The surface of
the skin is usually clean, but a dense growth of white mycelium
develops in the pulp and this finally produces masses of spores
lining pockets in the interior of the fruit. In late infections the
spores are formed earlier and the pulp only is affected.

Inoculations were carried out at Fresno, California, in August
and September, 1921, on figs classified into ten types according to
the various stages of ripening, with the object of finding out when
and in what manner infection took place. Thirty inoculations
were made on the trees for each of the younger stages (2 to 8),
while for the older stages (7 to 10) ten of each stage were inocu-
lated by cutting the fruit in half, placing spores inside, pressing
the halves together and incubating in uncovered dishes in the
laboratory. Adriatics were used throughout, together with Kadotas
and Calimyrnas for the younger stages, the last-named giving
inconsistent results probably on account of ‘souring’ which
affected the trees and was found in every case to check the

131

development of smut. Controls in the experiments on the trees
remained sound.

The results may be summarized as follows. On very hard, green
figs, the fungus made a start but only developed slowly. The
earliest stage of natural infection appeared to be when the fruit
was ripe but unshrivelled, ready for marketing fresh (stage 5).
Development was most rapid in stages 4 and 5; it was uncertain in
later stages when the fig was beginning to dry out; and in the
latest stages, when the pulp had become dry and translucent, the
spores could not be made to germinate.

Examination of the figs in the plantations showed that the rot
had started in many cases as a small spot under the eye when the
fruit was ripe for marketing fresh. Cultures were obtained from
many sound figs at this stage, an occasional fig being found infected
at a slightly younger stage, whilst figs still younger gave negative
results.

The disease appears to be disseminated by insects rather than
wind; ants, fruit flies, and beetles are able to make their way into
green figs with closed eyes. A premature rain in 1921, however,
was observed to favour the disease on trees when smut was well
under way.

‘Bunchy Top’ disease in bananas—interesting experiments.—
Queensland Agric. Journ., xviii, 4, p. 807, 1922.

The owner of a plantation at Murwillumbah claims to have dis-
covered a remedy for‘ bunchy top’ of bananas. In 1920-21 sulphur
was applied at the rate of 8 cwt. per acre, together with ‘island
fertilizer’. This was followed in 1922 by the application of 8 to
10 ewt. per acre of a mixture known as ‘basic super’, containing
45 per cent. lime and 17 per cent. phosphoric acid. In some cases
this mixture was applied round the stools to a radius of 3 or 4 ft.,
in others the whole surface was treated, the suckers being also well
dusted with the mixture before planting. All the suckers were
taken from ‘ bunchy top’ stock, but of the 800 planted since April
not one has so far contracted the disease. The stems are strong,
the colouring of the foliage excellent, and the growth of the plants
exceptional. Old diseased stalks similarly treated are now throw-
ing out vigorous centre leaves.

It is believed that the previous application of sulphur rendered
the phosphates readily available to the plants, in addition to its
action as a fungicide in the soil.

LupWIGS. Versuche mit ‘ Solbar’. | Experiments with ‘solbar ’. |—
Deutsche Obstbawzeit., \xvili, 21-22, p. 218, 1922.

The results of trials of the proprietary fungicide ‘solbar ’ carried
out by fruit-growers and horticulturists in Brandenburg during
1921, at the request of the local Chamber of Agriculture, are sum-
marized, The fungicide was applied at the recommended summer
strength of 1 per cent. Although the tests covered too short a
period to furnish definite data, the preliminary results are regarded
as satisfactory on the whole. Apple mildew [Podosphaera lewco-
tricha| was successfully combated in five instances, which included
the susceptible varieties Landsberger Renette and Cox’s Orange.

182

Good results were also obtained against American gooseberry
mildew [Sphaerotheca mors-uvae], rose mildew [S. pannosa], vine
mildew (Oidiwm tuckeri), and the mildews of Huonymus japonica
and Delphinium. Used against Fusicladium and Monilia of fruit
trees solbar gave conflicting results, no improvement being remarked
in some cases while in others the diseases were entirely checked.
In one case the leaf mould or ‘rust’ disease of tomatoes (Clado-
sporitum fulvum) was eradicated by two sprayings with solbar.
Fungous diseases | unspecified] of cucumbers were also successfully
treated in a suburb of Berlin. In an experiment conducted by the
Potato Research Institute at Steglitz, the percentage of scab [ Acti-
nomyces scabies| in tubers from ‘seed’ treated with 5 per cent. for
30 minutes was only 8, as against 28 in tubers from untreated
‘seed’.

Saumon (E.S.) & WorMALD (H.). Hop ‘canker’ or ‘ growing-off ’.—
Journ. Min. Agric., xxix, 4, pp. 354-359, 2 figs., 1922.

The cause of hop canker or ‘growing-off’ (the latter being the
descriptive name under which the disease is known in many
districts of the Weald of Kent and of Sussex) was attributed by
Percival (Journ. S.A. Agric. Coll. Wye, xi, pp. 87-89, 1902) to
Fusoma parasiticum. The disease causes a wilt of one or more
bines at. each affected ‘hill’. The wilted bines are usually found to
be almost severed at the base and easily come away from the root-
stock with a slight pull. The underground root stock is affected
by a canker, the infected portions being brown and dead. The
diseased bines examined by the authors, the basal parts of which
had been dead for some time, were often found to bear white
pustules of a fungus, with conidia of the Fusarium type. Bines
just beginning to wilt sometimes did not show these pustules, but
usually the mycelium of a fungus was to be found in the discoloured
tissues of the bark and of the wood, and in cultures made with
particles of such tissues on sterilized media, the fungus grew out
and eventually gave rise to Fusariwm fructifications. This evidence
that the latter was the organism responsible for the disease was
strongly supported by successful inoculation experiments carried
out by the authors on hop sets, although the results were not quite
conclusive, owing to the fact that some of the control sets also con-
tracted the disease. ‘ ;

Hop canker seems to be favoured by moist soil conditions, and
the general experience of hop-growers is that the disease 1s worse
in a wet season or following a wet winter, and that the hills are
likely to be more severely attacked on wet, clayey patches or in
shaded parts than on lighter soil or in portions of the garden more
exposed to sunshine.

Some varieties of hops appear to be more susceptible to the
disease than others; among the more resistant the authors mention
the varieties Fuggles, Cobbs, and Old Golding.

Direct preventive measures consist in hard ‘ cutting’ or ‘ dressing ’
of all the hills in the affected parts of the gardens, all the brown
parts of the root stock being pared away, and in the grubbing up
and destruction of all dead plants. Drainage or cultivation to

133

remove the moisture of wet land, or letting in the sun, appear to
have a favourable effect in keeping the disease in check.

Duca@aAr (B. M.). The sizes of the infective particles in the mosaic
disease of Tobacco.— Ann. Mo. Bot. Gurd., viil, pp. 343-356,
1921 [1922].

By arranging a series of porous filters of different degrees of
permeability the author sought to determine the two adjacent
members of the series, one of which would freely allow the virus of
tobacco mosaic to pass while the next would stop all but a small
quantity of it.

These two were found to be a Livingston spherical atmometer
cup and a cylindrical atmometer tube. The former was of a type
found by experiment invariably to prevent the passage of the
vegetative cells and spores of Bacillus subtilis and to be finer than
the Mandler diatomaceous filter. The cylindrical atmometer tube
was still finer.

The juice to be filtered was prepared by a standard method and
the wetted filters were lowered into a vessel containing it, every
precaution being taken to avoid accidental contamination. The
filtrate was sucked into the filter at a reduced pressure of one-
fifteenth to one-thirtieth of an atmosphere, about fifteen minutes
being required to obtain sufficient for testing in the case of the
spherical cup and 30 to 45 minutes in the case of the cylindrical
tube.

The filtrate was then tested for the presence of the virus by
inoculating rapidly-growing tobacco plants through wounds. In
the two series reported, eighteen out of twenty plants inoculated
with the filtrate from the spherical cup got mosaic within eighteen
days and only one of those inoculated from the tube, in one case,
and nineteen and five respectively in the other.

It was concluded that the size of the infective particles must lie
between the pore sizes of the two filters mentioned, probably close
to that of the cylinder. Subsequent tests indicated that the pore
sizes of these two filters were sufficiently close together to obviate
the necessity of seeking for an intermediate size. Tests with milk
and dextrin showed that the size of the infective particles was
greater than that of the colloidal particles of dextrin, but less than
that of casein. Haemoglobin was selected as having particles of
intermediate size. The haemoglobin colloidal solution was freshly
prepared by a standard method and was found to behave just like
the tobacco mosaic virus, passing freely through the spherical cup
and only in very small quantity through the cylinder. It was also
found that the spherical cup allowed approximately 50 per cent. of
the gelatin particles from a 1 per cent. solution of gelatin to pass.

From these experiments the author states that it seems clear
that with approximately equal pressures and equal time intervals
the infective particles of mosaic tobacco juice have about the
same capacity to pass porcelain filters as the colloidal particles of
freshly prepared haemoglobin. They have apparently a greater
capacity for filter passage than 1 per cent. gelatin particles. As
the particles of gelatin are not apparently very much larger than
those of haemoglobin the conclusion that the virus particles are
about the size of the latter is strengthened.

134

Bechhold has indicated that haemoglobin particles are 33 to 36 pu
[0-033 to 0-036 pt] or less than one-thirtieth of the breadth of the
majority of bacterial parasites of plants. If the infective particles
of tobacco mosaic are of the same order of size as colloidal haemo-
globin particles they are evidently very different from the known
bacterial plant pathogens.

SmirH (K. M.). Mosaic disease in plants.—JVature, cx, 2768,
p- 668, 1922.

The writer records the discovery, in potato plants affected with
mosaic, of the invariable presence, in some of the cells of the mosaic
tissue, of an abnormal body in close association with the nucleus;
this body is definitely connected with the disease and is apparently
similar to the peculiar body of amoeboid appearance which was
described in the cells of mosaic diseased maize by L. O. Kunkel in
- 1921 in Hawaii [see this Review, i, p. 194]. No attempt is made at
present to define the nature of this body.

Ramsgortom (J.). Orchid mycorrhiza.—Trans. Brit. Mycol. Soc.,
viii, 1 & 2, pp. 28-61, 6 pl., 1922.

The author reviews the work so far done on mycorrhiza, espe-
cially in orchids, and discusses the fungus-root association in
Gastrodia, Ericaceae, Pyrolaceae, Burmanniaceae, and Gentianaceae.
The endotrophic mycorrhiza of orchids is described and figured
from photo-micrographs taken from preparations made by the late
Mr. J. Charlesworth, whose success in the germination of orchid
seeds by inoculating them with pure cultures of the appropriate
fungus on a large scale is stated to have been remarkable. The
method employed in using the cultures is described. In discussing
the germination of orchid seeds in the absence of fungi, Noél
Bernard’s experiments with solutions of increasing concentrations
of salep and sugar are referred to, and cases in which concentrated
nutrient solutions can replace the fungus are mentioned. It is
recalled that Bernard found that the Rhizoctonia of these mycor-
rhiza has the power of increasing the concentration of the nutrient
medium, and this stimulation of autonomous germination by con-
centrated solutions is compared with the activation of certain eggs
by various substances in the absence of fertilization.

With reference to the enormous number of seeds produced by
orchids, the writer believes that it is in some way related to the
distribution of the endophytic fungus in nature. A general survey
of families of plants in which endophytic mycorrhiza are typically
developed shows that it is the rule for them to have small seeds,
ill-adapted for germination; this suggests that in families adapted
to a mycorrhizal habit there is a tendency for the seeds to become
dependent upon the fungus for successful germination, whilst there
is a correspondingly greater production of seed. The writer
advances the hypothesis that saprophytism has arisen by the
mycorrhizal fungus taking over some of the functions necessary in
germination and relieving the flowering plant of the need of
excessive food production for the developing seed and thus of the
necessity for carbon assimilation.

In reviewing the various theories which have been put forward

135

to account for the fungus-root association, the author thinks that,
referring only to orchids, it seems most reasonable to regard the
condition as having arisen from parasitic attacks by the fungus.
The ability of the fungus to transport nutrient solutions has been
made use of by the flowering plant, which has turned the tables on
the aggressor and ended by making use of the latter for its own
needs. The facts at present known, however, are insufficient to
decide between the various theories in regard to the origin and
significance of mycorrhiza.

Friror (J. W.). Pecan rosette.— Bull. Georgia State Coll. Agric.,
x, 19, 12 pp., 4 figs., 1922.

The present paper antedates by several years the most recent
work on pecan rosette, its publication having been delayed by war
conditions. Hence Rand’s view that the disease is an infectious
chlorosis [see this Review, i, p. 440] is not taken into account.
The writer regards rosette, which is extremely prevalent in Georgia,
as a physiological disturbance caused by the inability of the root
system of certain pecans to adapt itself to unfavourable soil con-
ditions. Among the latter are mentioned lack of water-holding
capacity ; rapid leaching or evaporation of soil water during the
growing season; shallow soils, especially with-a hard pan in the
sub-soil; and lack of suitable plant food.

In 1916-17 a block of forty-three Stuart pecan trees at Louisville,
Georgia, was mulched with pine straw, the mulch remaining on the
ground till the spring of 1919. In 1915 this block had eight trees
free from rosette, fifteen rosetted without dead twigs, and twenty
rosetted with dead twigs: in 1919 forty of the trees were completely
healthy, while the remaining three showed symptoms of rosette
without dead twigs. Thus there was an improvement of 400 per
cent. in the incidence of the disease amongst the trees in the mulched
block. In an untreated control block the conditions of the trees
remained stationary during the period under review.

Before applying the mulch, the trees should be well fertilized
with stable manure or 5 to 25]b. per tree of a mixture containing
10 per cent. phosphoric acid and 4 per cent. nitrogen. In orchards
comparatively free from the disease, the cultivation of heavy crops
of field peas and other legumes will probably eliminate rosette
without further treatment.

Durrénoy (J.). Sur la tuméfaction et la tubérisation. [On
tumefication and tuberization.|—Comptes rendus Acad. des
Sciences, elxxiv, pp. 1725-1727, 3 figs., 1922.

The formation of tumours, which is accidental and pathological
in most plants, may be habitual in certain species. Thus in various
species of Lucalyptus the collar of the seedling is always distended
by proliferation of the axillary buds of the cotyledons and of the
first leaves, which, in fusing, unite with the first internodes of the
stem, the hypocotylary axis, and the base of the root. A tubercle
is thereby formed which is provided with roots and numerous
buds, and which buries the lower stem internodes in a mass of
woody parenchyma, with wide medullary rays separating bundles

136

of twisted fibres. Similar tubers occur at the base of arborescent
Ericaceae.

Nodules appear below the collar of most of the young Arbutus
unedo trees of the Pifiada d’Arcachon, and increase in size with the
development of the tree. On its distended base the mature tree
forms vigorous branches. The cause of the distensions is obscure ;
in the eambium and phelloderm of the tumours of Arbutus bacteria
were occasionally found, but they did not develop satisfactorily in
the media tried by the author.

The swellings do not appear to be essential to the life of the
plant. They are not invariably found on Arbutus, and seedlings
grown under aseptic conditions form cotyledons though no hyper-
trophy occurs.

In the autumn and winter these tumours accumulate in their
hypertrophied and hyperplasied medullary rays large quantities
of starch. Thus they possess the anatomical and physiological
characters of tubers, and present an example of transition between
tumefication and tuberization.

JoNES (L. R.). Experimental work on the relation of soil tempera-
ture to disease in plants.—T rains. Wisconsin Acad. Sci., Arts
& Lett., xx, pp. 433-459, 4 figs., 5 pl., 1922.

The primary purpose of the present paper is to explain what is
essentially a new method of attack upon a group of phytopatho-
logical problems, aimed, broadly stated, at gaining a clearer under-
standing of the relation of environment to the occurrence of disease
in plants. In an attempt at putting the work upon an experimental
basis, the relation of soil temperature to certain cases of soil
parasitism has been selected because of simplicity of definition and
practicability of attack, and for the sake of illustration the author
briefly summarizes the results so far obtained in the work at Madison
by means of the now well-known Wisconsin constant temperature
soil tanks, on the Fusarium wilt of the tomato, the potato stem
canker caused by Rhizoctonia solani, and the root rot of tobacco
due to Thielavia busicola.

It is evident that this work has already defined problems which
are distinctly physiological rather than pathological. Each disease
results from the vital inter-relation of two organisms, the parasite
and the host, both of which are affected by variations in soil
temperature. The latter also induces concomitant variations in
soil moisture, aeration, and other factors, though these can be
eliminated, in great part, by the apparatus used. It is recognized
that the methods of investigation employed cannot give all the data
necessary for an interpretation of the biological principles involved
sufficiently full to account for the influence of the environment on
these diseases under natural conditions. Out of the mass of complex
and inter-related problems only a few of the simplest have as yet
been attacked. The assistance of the physiologist is required for
the study of such matters as the relation of soil temperature to the
rate and character of root development, the correlation between soil
and air temperatures as affecting the extent and type of development
of root and shoot organs, the relation of soil and air temperatures
to the nutritive and reproductive processes, and consequently the

;
7
%

137

proper correlation of these with the natural sequences in the plant's
development, &c.

There are, however, some distinctly pathological problems for the
development of which plant pathologists cannot wait for the help
of others. Such are the questions of the evident and immediate
influence of soil temperature and other environmental factors on
the occurrence, severity, and geographical distribution of certain
introduced parasites, and also the question of the relation of
environment to disease resistance. The author is convinced that
plant pathologists must continue to inquire with increasing pre-
cision into the relation of environment to disease development.
Not only must they give to these problems some of their own best
efforts, but they must seek the assistance of special workers in the
related fields, physiologists, ecologists, geneticists, and plant cul-
turists. Working thus in a spirit of correlation and co-operation,
the author believes that prompt and important progress is assured,
and the results already obtained [ef. this Review, i, pp. 2438, 281, and
ii, pp. 67, 76] amply justify this belief.

Jones (L. R.), McKinney (H. H.), & FeLLows (H.). The influence
of soil temperature on Potato scab.— Wisconsin Res. Bull, 53,
35 pp., 9 figs., 1922.

In comparing the very general prevalence and serious nature of
common potato scab [| Actinomyces scabies] in America with the
situation in northern Europe, where the disease is usually of minor
importance in spite of the highly intensive cultivation of potato
and the abundant use of stable manure from animals fed on cull
potatoes, the conclusion was reached that the development of scab
must evidently be influenced by different environmental factors.
Various reasons suggested that the temperature of the soil might be
particularly important. The results of five series of experiments
in greenhouses, using the ‘ Wisconsin temperature tank’ method
with seven gradations of soil temperature ranging from about 11°C.
to 30-5°C., all other soil and air conditions (including moisture)
being kept alike and approximately constant throughout each series,
show that such is the case. The same strain of the parasite was
used throughout, and the disease developed at all the soil tempera-
tures used but was comparatively slight at both extremes. The
optimum temperature under the conditions of the experiments is
considered by the authors to lie at about 22°C., this being near the
mean between the optimum (23°C.) as measured by the number of
seabby tubers and the optimum (20-5° C.) as indicated by the total
tuber surface scabbed. A preliminary field trial in 1919, in which
three gradations of soil temperature, roughly 19°, 21°, and 25° C.,
were maintained in small plots by special apparatus, showed that
the amount of disease increased with the temperature, the percentage
of scabbed tubers being 6-25, 13-23, and 30-55 respectively.

Field observations made both in Europe and America seem to
agree generally with these experimental results; they indicate that
the disease is more prevalent in regions having warm growing
seasons than in regions with cool summers, and that a greater
amount of scab seems to develop in a given locality during a warm
season than during a cool one. An examination of the weather

138

records of the leading Wisconsin potato-growing districts showed
that the mean air temperatures for July and August during the
hottest seasons (when scab is most prevalent) approximate to the
optimum soil temperature range for scab obtained in the experi-
ments. :

The influence of soil temperature on the disease must obviously _

be considered in relation to its effects both upon the parasite and
upon the host. There are indications that the stimulating influence
of comparatively high temperatures on the prevalence of the scab
organism in the soil is cumulative from season to season, whereas
the influence upon the host is immediate and temporary. The data
obtained by the authors indicate that the temperature optimum for
scab lies between that for the growth of the parasite in pure culture
(from 25° to 80° C.) and the definitely lower optimum for the rate
of tuber development, being somewhat closer to the latter. It must,
however, be noted that the influence of soil temperature on the
different organs of the potato plant is not uniform, and that it
varies also with the stage in their development; exact data are not
yet available on these points. The evidence at hand suggests that
rapidly growing tubers scab more severely than slow growing ones,
and that there may be certain differences in the chemical com-
position of the tubers developing under different conditions that
may influence their relative susceptibility to infection. On the
whole the immediate relation of temperature to the development of
scab seems to be more closely correlated with its influence upon
potato tuber development than with that upon the growth of the
parasite.

Mintarp (W. A.). Common scab of Potatoes.—Ann. Appl. Biol.,
ix, 2, pp. 156-164, 2 pl., 1922.

Common scab of potatoes [ Actinonvyces scabies], though ubiquitous
in England, occurs in a virulent form only in certain circumscribed
localities, such as some districts of Yorkshire, where the crop is
often so severely scabbed as to be practically unsaleable. Farmers
have been obliged in some cases to stop growing potatoes on land
which is otherwise eminently suitable for their cultivation.

The symptoms of the disease are fully described. Mature scabs
vary considerably in general appearance, some having a pitted
aspect owing to the depression which is formed in the early stages
of the disease never becoming filled in by the subsequent develop-
ment of cork, while in other cases the scab stands out above the
surface of the tuber in knob-like, corky projections. These two
forms represent the chief types of the disease when it occurs in its
most virulent form. In Britain, however, the commonest form is
intermediate between the two extremes; it is slightly raised and
is also characterized by an irregularly concentric series of wrinkled
layers of cork arranged around a central core or depression.

The author isolated ten strains of Actinomyces from scabbed
potatoes. These showed considerable variations one from another
trom the beginning, and further variation was found to result from
differences in the culture media, age of the cultures, and the like.
Still, in view of the absence of a clearly defined limitation of the

139

species A. scabies, all the strains isolated were regarded as belonging
to this species provided that they were capable of inducing scab.

Inoculations showed that five out of seven of the strains tested
caused scab, the negative results with the other two being perhaps
due to early ripening of the potato varieties inoculated in these two
cases.

It is considered that common scab can be caused by various
strains of Actinomyces, but further work is required to decide
whether they should all be regarded as forms of a single species. -

STEVENS (H. P.). Sodium silicofluoride as a mould preventive.
Bull. Rubber Growers’ Assoc., iv, 5, pp. 227-228, 1922.

Further tests in mould prevention [see this Review, i, p. 263]
indicated that sodium silicofluoride in the proportion of 1-8 gm.
to 3,000 ce. of latex prevents all but the slightest traces of mould
developing in sheet rubber during transport. Samples treated with
only 0-6 gm. to the same quantity of latex (i.e. 0-02 per cent.)
arrived in a mouldy condition, so that this quantity is evidently
insufficient. The figures for the breaking strain and rate of cure of
the samples treated with sodium silicofluoride are satisfactory,
though slightly below the average.

SUNDARARAMAN (S.). Helminthosporium disease of Rice. Ayric.
Res. Inst. Pusa Bull. 128, 7 pp., 4 pl. (2 col.), 1922.

During 1918-19 the rice crops in the deltaic tracts of Godaveri
and Kistna, Madras, were severely attacked by several pests and
diseases, including leaf spot caused by Helininthosporium. The
latter occurred principally in badly drained fields that were flooded
by unusually heavy rain while the ears were forming. Spots
appeared on both sides of the leaves, leaf-sheaths, and glumes.
These spots measured 1 to 14 by 0-5 to 3 mm., and had brown
centres with smoky black patches formed by a growth of dark
brown, septate hyphae and spores. As they increased in size they
frequently merged, discolouring the entire area of the leaf.

The development of the parasite is promoted by continuous
heavy rain and by cloudy, close weather. Under such conditions
the disease spreads rapidly from one plant to another. The nodes
are sometimes attacked towards maturity and blackened with a
dense growth of conidia and conidiophores. The surface of the
glumes may also be covered with a black, fluffy mass of conidia and
conidiophores, the grains within being shrivelled and discoloured,
Generally, however, the grains and other parts of the ear are not’
affected.

The mycelium in the leaves consists of numerous, septate, hyaline
hyphae passing from cell to cell. Dark brown conidiophores, 70 to
175 by 5-6 to 7 pw, emerge from the stomata and epidermal cells and
bear the spores on knee-shaped projections. Spores are found only
on old, mature spots and are few, deep olive brown in colour, with
5 to 10 septa, 45 to 106 by 14 to 17 y, and faleately sigmoid in
shape. These measurements do not agree with those of Helmintho-
sportum sigmoideum or H, macrocarpwm previously known on
rice. H. oryzae Miyabe & Hori has been recorded on rice in Japan,

140

but the author has not seen a description of it [see this Review, i,
. 414].

i The fungus was isolated and grown in pure culture on rice
agar and other media. In culture the conidiophore bears several
conidia, formed successively, near the top [up to 8 are figured].
Germination is generally from the end cells. Inoculation experi-
ments on the leaves, leaf-sheaths, and ears confirmed the field
observations that the fungus is a weak parasite under normal con-
ditions, the spots formed being limited in size. A serious reduction
of yield on account of this disease is scarcely to be feared in
ordinary seasons.

SurcLirre (H.). Disinfectants. Abridged report by the [Rubber
Growers’ Association| scientific staff in Malaya.— Bull.
Rubber Growers’ Assoc., iv, 5, pp. 224-227, 1922.

Three new disinfectants, ‘Superol’, ‘Parakol’, and ‘ Rustikol’,
and a modified insecticide, ‘Solupar’, have been tested for their
fungicidal efficiency. The method of testing was the same as
that described in previous reports (a culture medium was prepared
containing 2 per cent. bovril, 2 per cent. glucose, and 6 per cent.
agar, and to this was added enough of a 25 per cent. solution of the
substance to be tested to give concentrations of 10, 5, and 2 per cent.
For lower concentrations weaker solutions of the fungicide were
used). In the present case the fungus used was a pure culture of
a Gloeosporvum isolated from dead Hevea branches.

‘Parakol’ was found to be a very good disinfectant, only giving
a growth equal to the control at a concentration of 0-063 per cent.
after ten days; owing to its deep green colour it would be useful
in daily painting against black line canker [Phytophthora sp.].
‘Rustikol’ is also a good disinfectant (growth equalled control in
eighteen days at 0-004 per cent. concentration), suitable for treating
wounds or painting the cut ends cf roots or branches. ‘Superol’ is
very similar to ‘Chinosol’, a clear yellow solution with a strongly
acid reaction. It gave a growth equal to the control in thirty-three
days at 0-008 per cent. ‘Solupar’ containing 1 per cent. carbolic
acid was efficient at a strength between 10 and 15 per cent. Owing
to the absence of material it has not been possible to test ‘Solupar ’
as an insecticide, for which it is primarily intended.

JARVIS (E.). Cane pest combat and control— Queensland Agric.
Journ., xviii, 4, pp. 277-279, 1922.

On the Herbert River in Queensland the most serious disease of
sugar-cane appears to. be the gumming disease caused by Bacillus
vascularum. It is found chiefly in the most commonly grown
variety, Clark’s Seedling (H. Q. 426) but the Badila cane appears
to be becoming increasingly susceptible. The variety H.Q. 409 is
practically immune, but is unpopular because of its slow growth
and tendency to arrow early and profusely. The chief factors
which predispose to gumming are poor drainage, an impervious
subsoil two or three feet from the surface, defective cultivation, and
a heavy rainfall. Of these, bad drainage appears to be the most
important. Little or no attention is paid to the selection of healthy

141

_ canes for ‘seed’ purposes. The planting of sound setts and burning
the trash are recommended.

Lee (H. A.) & Kopke (E. W.). Mosaic disease of Sugar-cane in the
Philippines.— Philipp. Agric. Rev., xiv, 4, pp. 418-421, 5 pl.
(1 col.), 1922.

Yellow stripe or mosaic disease was first observed in the Philip-
pine Islands by Lyon about 1910 or 1911 and has since been
reported from a number of districts.

A brief and admirably illustrated description of the symptoms of
the disease is followed by a discussion of the losses, which in the
Cebu Purple variety may amount to 20 per cent. Severe stunting
also occurs in the H-109 and Yellow Caledonia varieties, though the
latter is not often attacked, while the stunting of D-1135 is slight.
The Japanese forage canes, Uba, Zwinga, &c., are immune from
mosaic, but their sugar production is very poor, and their use in
the Philippines is hardly to be recommended at present. The first
and most essential step in the control of the disease is the selection
of healthy setts for planting.

WELLEs (C. G.). A provisional list of the parasitic fungi of the
Philippine Islands.—Philipp. Agric. Rev., xv, 2, pp. 149-202,
1922.

This list of the parasitic fungi known in the Philippine Islands
up to 1922 contains about 260 genera and 958 species. A com-
plete host index is appended.

Dorpce [E. M.]. South African Ascomycetes in the National
Herbarium. Parts I & II. JBothalia, i, 1, pp. 5-82, & 2,
pp. 65-82, 8 figs., 1922.

These papers deal with collections of South African fungi pre-
served in the National Herbarium at Pretoria. The groups here
considered contain a large proportion of parasitic forms, chiefly on
leaves ; some eighty-five species are mentioned, of which thirty-five
-are new. The species are either fully described, or their former
descriptions are enlarged and amended following the examination
of further material. The nomenclature and classification follows
the recent work of v. Héhnel, Theissen, and Sydow. Four new
genera are proposed, and one old genus is shown to be superfluous.
Dielsiella was originally erected for those species of Cycloschizon
whose spores become brown, but this is now shown to be character-
istic of Cycloschizon itself, and so the former genus disappears. Of
the new genera three belong to the group Polystomellaceae.
Macowaniella [M. congesta (Wint.) Doidge on Carissa arduina]
differs from Hysterostomina in the presence of free mycelium, and
from Lembosiodothis in the absence of subcuticular bands. Isipinga
(1. areolata n.sp. on Kuclea natalensis and I. contorta Doidge on
Trichocladus ellipticus) differs from Hysterostoma in the presence
of well-developed aerial mycelium, and from Asterodothis in the
absence of a central column or foot. Palawaniella (P. eucleae n. sp.
on Euclea macrophylla) differs from Palawania chiefly in the centri-
petal development of the stromata, and in the epidermal, rather
than sub-epidermal, hypostroma; and from Pleiostomella in the

142

brown, two-celled spores, and loculi less definitely arranged in rings.
Among the Stigmataceae, Parastigmatea (P. nervisita n.sp. on
Stephania hernandifolia) only differs from Stigmatea in its spores
being hyaline and continuous.

Van DER Bu (P. A.). A Host list of the Polyporeae occurring
in the Union of South Africa.—Kew Bull. Misc. Inform. 6,
pp- 177-182, 1922.

The author cites as parasitic the following species, only those
hosts being noted here which are stated to be living.

Polystictus spp. are included under Polyporus.

Fomes applanatus (Pers.) Gill. [including F. annularis Lloyd,
F. leucophaeus (Mont.) Cke, F. vegetus (Fr.) Cke, F. australis (Fr.)
Cke] on Olea laurifolia; F. conchatus (Pers.) Gill. on Melia
azedarach; F. connatus (Weinm.) Gill. on Curtisea faginea; F. geo-
tropus Cke on Ocotea bullata, Podocarpus sp., and Virgilia capensis ;
F. rimosus (Berk.) Cke on Acacia sp., Curtisea faginea, Elaeoden-
-dron croceum, Kiggelaria africana, Olea laurifolia, Plewrostyla sp.,
Ptaeroaylon utile (a heart rot), Rhus laevigata, Schotia latifolia,
Scolopia mundtii, and Xymalos monospora; F. senex (Nees &
Mont.) Cke on Sizygiwm sp.; F. yucatensis (Murr.) Sace. & D. Sace.
on Olea sp. and Trema bracteola.

Lenzites betulina (L.) Fr. (including L. guineensis Fr.) on Celtis
kraussiana, Olea lawrifolia, Pinus sp., and Quercus sp.

Polyporus fruticum Berk. & Curt. on Rubiaceous plants; P.
lucidus (Leys.) Fr. (including Ganoderma sessile Murr., P. capensis
Lloyd, and Ganoderma fulvellum Bres.) on Acacia sp., A. mollis-
sima, Albizzia amara, A. fastigiata, Olea lawrifolia, O. verrucosa,
and Sulia sp.; P. patowillardii Rick on Scolopia mundtw; P. san-
guineus (L.) Fr. on Aloe arborescens and A. marlothiv; P. sul-
phureus (Bull.) Fr. on Quercus sp. (a wound parasite) ; P. versicolor
(L.) Fr. on Prunus persicu (a wound parasite).

Trametes incondita Fr. on Ptaeroxylon utile; T. obstinatus Cke
on Acacia mollissima, Acacia sp., Citrus, and a number of undeter-
mined hosts; 7. swhflava Lloyd on Celtis kraussiana.

BuB&dk (F.). Une nouvelle espéce du genre Urocystis. [A new
species of the genus Urocystis.|—Bol. R. Soc. Esp. Hist. Nat.,
xxii, 4, pp. 205-207, 2 figs., 1922.

A fungus found on Loliwm perenne near Algodor, in the Province
of Toledo, Spain, in 1921, and sent to the author by Gonzalez
Fragoso with the suggestion that it might be a new species of
Urocystis, was compared with U. occulta and U. agropyri. It
resembles the former in attacking the stems, leaf-sheaths, leaves,
and spikes with the result that poor spikes are formed, or none at
all, but the spore balls often contained 4 or 5 central spores instead
of 1 or 2, seldom 8 or 4, as in U. occulta. The spores of the Lolium
fungus were also slightly more flattened and considerably smaller
(9 to 16 by 9 to 13-54). The peripheral cells usually covered the
whole surface of the spore ball, which is not the case with U. occulta,
where the surface is dotted with isolated peripheral cells, having
larger dimensions (7 to 16 as against 6 to 11 y), a thicker membrane
(2 as against 1 «), and a smaller lumen.

143

The chief differences from U. agropyri are the larger and more
complex spore balls, smaller and darker central spores, and smaller
and more flattened peripheral cells. The spore mass is also darker
than that of U. agropyri on the same host plant, while the latter is
restricted to the leaf sheaths and leaves, and grasses attacked by it
never produce stems.

The new fungus is named Urocystis bolivari Bubak & Fragoso,
and a Latin diagnosis is given.

United States Department of Agriculture, Federal Horticultural
Board, Service and Regulatory Announcements, January to
June, 1922, pp. 17-25, 27th October, 1922.

The Plant Quarantine Conference called by the United States
Department of Agriculture in May 1922, was attended by Dutch,
English, Welsh, and Belgian representatives, as well as by over two
hundred prominent American nursery-gardeners and a number of
State officials. The primary object of the Conference was to con-
sider whether any modification of regulation 3 of Quarantine 37,
which provides for the entry under permit of certain classes of
bulbs, stocks, cuttings, scions, and seeds of flowers, fruits, trees, and
shrubs into the United States, was desirable. It was also hoped to
promote a better understanding of the necessity of safe-guarding
the major national crops against the introduction of destructive
pests and diseases. At a conservative estimate, the annual loss to
American agriculture from imported pests amounts to $2,000,000,000
exclusive of imported bacterial and fungous diseases of plants.
Amongst the most serious of the latter are citrus canker | Pseudo-
mona citri|, which has cost about 52,130,000 for control work since
its introduction with Japanese trifoliate orange stock thirteen
years ago; pine blister rust [Cronartiwm ribicola| which was intro-
duced from Germany with a consignment of American white pine
seedlings, and now threatens to exterminate a forest stand valued
at $516,750,000 ; and potato wart [Synchytrium endobioticum]| now
restricted to parts of Pennsylvania, Maryland, and West Virginia.
Chestnut blight [ Hndothia parasitica], introduced with a small ship-
ment of Oriental chestnut trees, has already destroyed half the
American chestnut stand. New York and Pennsylvania have
suffered the most serious damage, and the disease is now spreading
down the Appalachian Mountains to North Carolina and Alabama,
and westward into West Virginia. The present stand is valued at
$58,000,000. It is stated that no important pest is known to have
been imported and become established since the passage of the
Quarantine Act in 1912.

A proposal made by the foreign delegates for an international
agreement permitting the free movement of plants between countries
under inspection and certification was rejected by the Secretary of
Agriculture and the Federal Horticultural Board. It was pointed
out, inter alia, that the United States, with their wide climatic
range, would run a far greater risk of permanently accommodating
imported pests and diseases than would the northern European
countries where atmospheric conditions were adverse to the estab-
lishment of such organisms. Moreover, the shipments from Europe
into the United States would be out of all proportion to the

144

exporting capacity of the latter. America would therefore have
everything to lose, and little, if anything, to gain by the proposed
amendment.

In the report of the advisory committee of the Conference, com-
prising representatives of Universities and the trade, to the
Secretary of Agriculture, the opinion was expressed that no
material changes are necessary either in Quarantine 37 or in the
regulations of the Federal Horticultural Board for its enforcement.
The idea of committees representing the various interests affected
by the regulations is commended in the report, as tending to promote
a better understanding between the different parties concerned. In
view of the serious losses to American agriculture from pests and
diseases imported before the establishment of Quarantine 37, the
committee declared that much greater care than formerly must be
exercised to exclude them.

In reply to certain criticisms directed against Quarantine 37,
Dr. C. L. Marlatt (Chairman of the Federal Horticultural Board)
pointed out that every facility is given for the importation, by permit
or otherwise, of all necessary plant material for food, manufacturing,
or medicinal purposes. During the last two years no less than
6,000 open continuing permits have been issued for the introduction
of bulbs, fruit and rose stocks, and fruit, forest and ornamental
trees, which are not restricted as to quantity. Of the so-called
prohibited plants, the number of which permitted entry in any
single consignment is controlled, permits authorizing the importa-
tion of over twenty-nine million have been issued since 1919. At
the same time he states that many European countries have closed
their frontiers to corresponding material from America. The fear
that European countries will ‘retaliate’ for the American Quaran-
tine restrictions by closing their doors to American meat and grain
exports is, he believes, absolutely without foundation. The free
entry into the United States of foreign plants has been the proved
cause of incalculable damage, and while its resumption is out of
the question, he considers that ample provision is made under the
present system for all necessary imports.

An Act to make special provision for the control of the disease of
fruit and other trees known as fireblight.—New Zealand,
1922, No. 20, 16th October, 1922.

The ‘Fireblight Act’ 1922 replaces the previous order of 1921
declaring hawthorn a noxious weed [see this Review, 1, p. 283] and
empowers the Governor-General to declare any specified portion of
New Zealand to be a commercial fruit-growing district, and to make
regulations prescribing the trimming or cutting down in the manner
and at the times specified of all hawthorn growing within the
declared district or any part of it. If fireblight exists in the
district, the complete destruction of all hawthorn growing therein
within a specified time may be prescribed. The carrying out of
these orders falls on the occupiers of the land. If an occupier fails
to take the prescribed measures, an Inspector under the Orchard
and Garden Diseases Act, 1908, or other authorized officer, may
carry them out at his expense without releasing him from the
penalties which are prescribed for offences against this Act.

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

A eee DD MY COLOG ¥

Vor. IT APRIL 1923

GAUMANN (E.). Ueber das Septobasidium bogoriense Pat. | Septo-
basidiwm bogoriense Pat.|—Ann. Mycol., xx, 3-4, pp. 160-178,
1 pl., 22 figs., 1922.

Septobasidiwm bogoriense occurs throughout Java and has been
observed on Coffea, Erythrina, Paritiwm, Stachytarpheta, Morus
Calosanthes, Frazinus, Cinchona, Thea, Solanum, Citrus, Marsdenia,
Polyosma, and Manihot. It has also been found in Celebes on
Erythrina and Citrus. The fungus surrounds the entire circum-
ference of twigs and branches, extending in the direction of the
longitudinal axis. On the trunks of trees it forms more or less
circular or disc-shaped crusts, measuring up to 10 em. in diameter.
Occasionally it extends to the under side of the leaves.

S. bogoriense causes little direct damage to its hosts, its hyphae
being incapable of penetrating into sound tissues. Even wounded
tissues are invaded only to the depth of a few cell-layers. Indirectly,
however, it can cause considerable injury by predisposing to the
attacks of other parasites. Thus Cephalewros virescens, which pro-
duces cankers on tea plants, finds optimum conditions for develop-
ment in the humid atmosphere beneath its fungous mantle, while
Corticiwm salmonicolor and other parasites can invade the tissues
at places in the bark where S. bogoriense formerly occurred.

Three zones may be distinguished in the crusts formed by the
fungus, especially on Lrythrina and Morus: an outermost, 2 or
3 mm. in depth, thin, transparent, and pure white in colour, where
horizontal growth takes place; an intermediate, only about 1 mm.
deep, grey-brown or dingy purple, in which vertical development
occurs ; and an innermost, grey or yellowish-white on the surface,
brown internally, which represents the original growth on the
surface of the bark. In the early stages, the hyaline hyphae form
a closely woven, more or less flat tissue, covering the bark. Large,
shapeless haustoria penetrate the epidermal cells, causing no apparent
morphological alterations and acting as the sole connecting link
between the fungus and its host. The formation of narrow hyphal
columns from the surface mycelium then begins, the columns rapidly

D

>

146

increasing in thickness and, after they have reached a certain
height, expanding at the top to form a head resembling that of
a flat-topped coniferous tree, each expanded top uniting with others
in the vicinity. Thus a roof is formed resting on hundreds of
slender columns up to 600» in height and with arches between.
The roof is thin at first, but later the hyphae become densely inter-
woven and anastomose freely to form a thick, continuous crust, the
upper layers of which are composed of hyaline, the lower of brown
hyphae.

‘The formation of these thick hyphal coverings greatly hinders
the control of the fungus, repeated sprayings with Bordeaux, or
painting with 50 per cent. carbolineum having only a slight effect.
It is impracticable in large plantations to scrape off the covering,
but this appears to be the only means of removing it.

The normal structure of the fungus as described above may
occasionally be disturbed by the fillimg up of the intercolumnar
spaces with hyphae, or by a growth on the surface of the outermost
crust, in response to external stimuli such as particles of soil or
detritus resting thereon, of fresh layers of hyphae which grow
round and enclose the foreign particles. The latter process appears
to be frequent on Solanwm. :

The organs of fructification are formed in the upper, hyaline
portion of the outer crust. Small lateral protuberances on the
hyphae develop into ‘ teleutospores’ [probasidia] 6 to 9 » in diameter,
which are generally irregularly distributed throughout the mycelium
except in the form on Citrus, where they lie in clusters.

The wall of the ‘ teleutospores’ is hyaline and somewhat thicker
than that of the hyphae. Nuclear union, as in Jola, probably
takes place in the basidia, but could not actually be detected on
account of the minute size of the nuclei. Clamp-connexions are
present in the mycelium,

Germination takes place after a very brief interval, by the protru-
sion of a rather thick, four-celled basidium, which may be short and
remaining immersed in the mycelium (Citrus), or long and emerging
on the surface of the crust (Erythrina). This bears, on compara-
tively long sterigmata, long, narrow basidiospores, 9 to 16 by 2 to 3p,
closely resembling those of Jola javensis.

The fungus was successfully cross-inoculated on a number of
hosts, several of which (Solanum, Stachytarpheta, and Marsdenia)
are not indigenous to Java. ;

The author does not accept Raciborski’s identification of this
fungus with Helicobasidium mompa Tanaka.

SNELL (W. H.). Studies of certain fungi of economic importance
in the decay of building timbers, with special reference to the
factors which favour their development and dissemination.—
United States Dept. Agric. Bull. 1053, 41 pp., 8 pl, 3 figs.,
1922.

All the five species of wood-decaying fungi studied by the author,
viz. Lenzites saepiaria, L. trabea, Trametes serialis, Fomes roseus,
and Lentinus lepideus have been found fruiting more or less com-
monly on timber used in mill roofs or in basements. The damage
done by the first two to coniferous roof timbers is more considerable ©

147

than has been reported hitherto. The annual form of Fomes carneus,
considered by some mycologists as a distinct species, Trametes carnea,
is of common occurrence on beams in moist basements, but it is not
certain whether the perennial form also occurs. It is pointed out
that the high temperature and humidity of textile and paper mills,
canning factories, and the like are very favourable to the develop-
ment of wood-rotting fungi. The increased use in recent years of
inferior wood has accentuated the trouble. Numerous instances are
given of heavy losses from this cause.

The basidiospores of all the fungi mentioned germinated readily
on various agars, on red spruce wood, and in tap water, and
irregularly in distilled water. Investigating the effect of tem-
perature on the viability of the spores, the author accepted the
percentage of spore germination as the best criterion of the
influence of environmental conditions in the spread of infection.
At 40°C. the basidiospores of Lenzites saepiaria gave a high per-
centage of germination, while those of L. trabea and Fomes roseus
gave small percentages, and the germination of the spores of the
other two species was totally inhibited. The optimum temperatures
for rapidity of germination were: Lenzites suepiaria 32° to 35° C.,
L. trabea 28° to 32°C., Trametes serialis 30° to 32° C., Fomes roseus
28° to 82°C., Lentinus lepideus 28°C. Given sufficient time, large
percentages of the spores germinated at the lower temperatures
within the range of growth for each species. Diffused light was
found to have no effect on the germination of the spores. An
exposure of one day to direct sunlight in May and June did not
affect the viability of the spores materially. An exposure of two
days usually reduced the percentage of germination considerably,
sometimes entirely, while three days’ exposure usually killed most
of the spores. The germ-tubes showed no phototropic response.
In drying tests, basidiospores of Trametes serialis and Lentinus
lepidews (aged 10 days and 7 months respectively) were killed by
about ten weeks’ exposure at 28° and 32°C., and by about a month
at 836°C. At 40°C. fresh spores of Lenzites saepiaria survived for
two months, and of Trametes serialis six weeks in an unfinished
test. Five months old spores of Fomes rosews were killed in one
week at the same temperature. A number of tests made upon
different lots of varying ages seemed to show that alternate wetting,
either with free water or by atmospheric moisture, and subsequent
drying, reduced the viability of the spores. Basidiospores of
Lenzites suepiaria gave a germination of 25 per cent. after 2 years
and 10 months’ storage in an ice box, those of L. trabea 50 per cent.
after 1 year, of Trametes serialis 2 per cent. after 4 years and
3 months, of Fomes roseus less than | per cent. after 18 months,
and of Lentinus lepideus less than 1 per cent. after 2 years and
7 months.

With the exception of Fomes roseus, all the species under con-
sideration have been shown to be able to liberate large numbers of
basidiospores within buildings. In a series of experiments to test
the ability of sporophores to survive successiye wetting, spore-
liberation, and drying, Lenzites saeyiaria shed spores six different
times, but on the seventh attempt no visible spore-print could be
obtained. A fruit body of Trametes serialis kept in a dark fungus

148

pit shed spores for tifteen days successively. Observations upon
sporophores of this fungus in the bottom of a closed pit showed
that slight convection currents of air carried spores upward and
throughout the pit. In factories, air currents caused by machinery,
humidifiers, and heating pipes play an important part in the dis-
semination of spores cast into the air. Other observations suggested
the possibility of insects and other animals also being implicated in
the spread of infection.

A description of the macroscopic and microscopic characters of
malt agar cultures of the fungi with a key for identification by
mycelial characters is given. The cardinal temperatures for mycelial
growth were found to be as follows:

Minimum. Optimum. Maximum.

Lenzites saepiaria . About 8°C. 380°-34°C. Above 40° C.

Lenzites trabea . . 28°-80°C. Little above 36° C.

Trametes serialis . About 3°C. 28°C, Between 32° and
37°C.

Fomes roseus. . . Below 4°C. 30°C. Above 36° C.

Lentinus lepideus . About 8° C. 2010. Between 36° and
40° C.

Considerable attention was paid to the characters of the secondary
spores formed by these fungi in view of their possible occurrence in
nature under mill conditions. Oidia and chlamydospores were found
in agar cultures of Lenzites saepiaria and oidia in wood cultures ;
both kinds occurred in agar cultures of L. trabea; while only
chlamydospores were formed in agar cultures of Trametes serialis
and Lentinuslepideus. Certain of the physiological relations of the
oidia of Lenzites suepiaria and L. trabea and the chlamydospores
of Trametes serialis were studied. The germination temperatures
corresponded closely with those of the basidiospores of the respective
species, except that the oidia germinated better at the higher tem-
perature tried. Diffused light had no effect on the germination, but
the latter was prevented by ten hours’ exposure to sunlight in May.
Both oidia and chlamydospores were usually rapidly killed by
drying and by alternate wetting and drying. Only a few survived
drying at room temperature for some months. The oidia of Lenzites
saepraria and L. trabea were found not to be adapted for dissemina-
tion by air currents, but they could be disseminated by insects
(e.g. cockroaches) and water. This character may possibly be of
some importance in case oidia are found to be produced naturally
in mills. Thus far, however, the only secondary spores of these
fungi found in factories are the chlamydospores of Lentinus lepideus
that are borne on the fruit bodies.

Brewery (W. F.). ‘Sleepy disease’ of the Tomato.— Ann. Appl.
Biol. ix, 2, pp. 116-134, 4 pl., 1922.

‘Sleepy disease’ of tomatoes, which occurs in all parts of the
British Isles and has been attributed to Fusarium lycopersici Sace.
since Massee’s description of it in 1896, is shown by the author to
be caused usually by Verticilliwm albo-atrum, though it can also
be produced by the former fungus. Massee evidently observed

149

both forms but considered that they were merely different stages
(the Diplocladiwm stage and Fusarium stage respectively) of
F, lycopersici.

Plants attacked by Verticilliwm are usually stunted, the younger
internodes being badly developed. The leaves wither from the
base of the plant upwards, adventitious roots develop on the stem,
and ultimately the plant dies. The symptoms appear first about
the middle of April and increase in intensity for a month or more,
gradually subsiding to recur with renewed force at the end of
September. The attacks of F. lycopersict occur during the hottest
part of the season, in July and August in the Lea Valley, where
these observations were chiefly made on plants grown under glass.
It does comparatively little damage in the British Isles. Of 427
affected plants from different localities examined in 1919-20, 307
yielded Verticillium alone, 77 Verticilliwm and either Fusarvwm
Jerruginosum or F. sclerotioides, 26 Verticillium and F. oxysporum,
and 17 F. lycopersici alone.

Inoculations showed that infection by Verticillium can occur
through the stem or root but that, under the conditions of the
experiments, the period from June to September was unfavourable
for the development of the fungus. Inoculations through the soil
were also successful and sterile seedlings grown on agar were
readily attacked, the experiments indicating that penetration can
occur through the unbroken epidermis. Plants with hard, thin
stems, or obviously starved, succumbed most readily to attack.

Inoculations were also carried out with the four species of
Fusarium mentioned above as having been isolated from wilted
plants. F. ferruginosum and F. sclerotioides failed to produce
wilt under any conditions and must be regarded as saprophytes.
F. oxysporum caused a rot of the pith and cortex around the point
of inoculation and in some cases killed root tissues. It produced
a slight desiccation of the lower leaves at temperatures of 27-8° to
28-9° C., but wilt did not as a rule result from inoculation with this
species. Typical symptoms of wilt were produced by F. lycopersics
at temperatures of 28° to 29° C. but below 28° infection was
uncertain.

The walls of the vessels of plants affected with sleepy disease are
turned brown; and a brown, gummy substance frequently occupies
the lumen. As the culture liquids in which Verticilliwm was
grown were found to contain a substance capable of causing wilt
when filtered free from the fungus, an attempt was made to isolate
the enzymes produced during growth. No evidence was obtained
that endo-enzymes capable of causing wilt were present in the
mycelium, but Verticilliwm is stated to form a definite exo-enzyme
which is capable of discolouring the vessels and producing wilt in
seedlings when the latter are severed from their roots and placed in
turnip juice filtered from germinated spores. A brown, gummy
deposit was found in the wood in these cases, and the cambium was
destroyed near the end of the stem, The enzyme was precipitated
by absolute aleohol and found to be greatly reduced in activity by
heating to 100° C. for five minutes. The fungus was found to
produce amylase, inulase, emulsin, lipase, protease, erepsin, and
amidase.

150

Considerable differences were found in the virulence of different
strains of Verticilliwm studied in single spore isolations, as judged
by the period required to produce complete wilt. Indications were
obtained that high virulence is correlated with ability to form
carbonized hyphae and microsclerotia. Amongst the hosts other
than tomato that were successfully inoculated were potato, egg-
plant, cucumber, and Antirrhinwm (snapdragon). In cotton and
sycamore (Acer) the plants were stunted and the leaves withered
without wilting, while Capsicwm sp. was stunted but the leaves
remained green and only a few wilted, and in U/mus nothing but
slight stunting occurred.

Wilt due to Verticilliwm develops most rapidly in glasshouses
kept at temperatures between 15-6° and 24° C., the optimum being
21-1° to 22-8°. It is greatly delayed at 12-5° and practically
inhibited at 25° C. The minimum, optimum, and maximum tem-
peratures for the fungus, grown in pure culture, are 4-4°, 23.3°,
and 30° C. Verticillium wilt is a typical moderate temperature
disease, which explains its greater severity in the spring and autumn.
Suitable shading of the houses diminishes the intensity of the attack,
the plant probably being assisted by reduced transpiration. There
is no necessary relation between the disease and any special type
of soil, but plants grown in cool, clay soils are more liable to attack
than those in sand, and a high humus-content also appears to pre-
dispose to the disease.

Cultural methods of control have given promising results in the
Lea Valley. In badly infested localities resistant varieties such as
Manx Marvel or Bide’s Recruit should be grown. Attempts to
raise other wilt-resistant strains are being carried on by the author.
Slightly soft rather than hard growth should be encouraged. On
the first appearance of wilt the average day and night temperature
should be raised to over 25° C. A light coating of whitewash on
the glass is advisable. Watering the roots aggravates the wilting,
but a light overhead sprinkling is beneficial. The base of the
plants should be mulched to promote the development of new roots.
In one nursery the percentage of wilted plants was reduced in a
fortnight from 78 to 10 by these means. When the soil of the
beds is sterilized, great care is required to avoid the reintroduction
of the fungus as it develops very rapidly in sterile soil, especially
if rich in humus.

The spores that develop on external mycelium at the base of the
dead plants germinate and give rise to carbonized hyphae and
microsclerotia capable of overwintering. All dead plants and
débris should, therefore, be carefully removed as soon as the crop
is picked. The baskets in which the seedlings are carried, con-
taminate water, and the importation of young plants from infected
nurseries are all common sources of new infections. The vicinity of
the nurseries should be kept free from weeds (suspected to include
hosts of Verticilliwm), potatoes, Antirrhinum, &e. In a note at
the end the author records the occurrence of a sweet-pea wilt
which was found to be due to V. albo-atrwin, and successful cross-
inoculations between tomatoes, cucumbers, and sweet-peas were
obtained.

151

WHITEHEAD (T.). Varieties of Swedes resistant to finger-and-
toe.— Journ. Min. Agric., xxix, 4, pp. 362-368, 1922.

Trials carried out in 1921 with four British varieties of swedes,
together with two Danish resistant strains (varieties 4 and 25), on
three farms in Carnarvonshire, indicate that the Danish varieties
resist club-root or finger-and-toe [Plasmodiophora brassicae] to a
more marked degree, and in addition keep better and have a higher
feeding value than the British ones. The Danish variety 25 was
more resistant under North Wales conditions than the Danish
variety 4, which is the reverse of the results obtained in trials in
Denmark reported by Christensen | Tidskrift for Planteavl, xxvi, 1,
p--68, 1917].

ScHAFFNIT (E.). Versuch iiber die Empfanglichkeit verschiedener
Kohlsorten fiir den Erreger der Kohlhernie. [Experiments
on the susceptibility of various Cabbage varieties to the
organism causing club-root.|— Deutsche Obstbawzeit., Ixviii, 21-
22, pp. 211-212, 1922.

Experiments were carried out at Bonn in 1921 to test the suscepti-
bility to Plasmodiophora brassicae of ten varieties of white cabbage,
three of red cabbage, one of Savoy, one of kale, two of Brussels
sprouts, and two of kohlrabi. With the exception of the last-named,
all the plants showed a very high degree of susceptibility to the
disease, 100 per cent. of infection being observed in many cases,
The kohirabi was harvested in July, while the remaining varieties
were left until August, and this may possibly explain its relative
immunity.

LEHMAN (8. G.). Pod and stem blight of the Soy-bean.—Jowri.
Elisha Mitchell Sci. Soc., xxxviii, 1-2, p. 13, 1922.

The fungus Phomopsis sojae causes serious damage to the soy-
bean in North Carolina, especially in wet seasons. Pods, stems,
and occasionally leaves, are attacked, the heaviest losses resulting
from attacks on the pods. Very young pods drop off when attacked,
while older ones remain firmly attached. The fungus penetrates
the pod wall and invades the developing seed. The ovule may
abort at an early stage or the seed may become more or less
shrivelled according to the time and severity of infection. Seeds in
diseased pods are often completely invested with a conspicuous,
white, fungous covering. The minute, black pycnidia scattered over
the diseased areas begin to exude small, hyaline, single-celled spores
within a few days after their appearance.

The fungus has been isolated from stems, pods, and seed, and has
been observed to cause the death of seedling soy-bean plants by
growing from the seed coat on to the hypocotyl and causing its
decay. It overwinters in diseased stems and seed. The ploughing
under of diseased plants after harvest, use of healthy seed, and crop
rotation are recommended.

MivpratH (D. G.). Control of diseases of Cucumbers in green-
houses.— Monthly Bull. Dept. Agric. California, xi, 5-6,

pp. 430-437, 4 figs., 1922.
During the last two years the cucumber-growing industry has

152

made rapid progress in California, and a brief description of the
more important diseases and the means of controlling them is given
in this paper for the assistance of growers.

Mosaic disease is said to be controlled to some extent by destroy-
ing affected seedlings. The method recommended is to sever the
main stem at the ground level and allow the vine to remain for
36 to 48 hours before further touching it. By this time the
virus in the severed vine will have lost much of its strength, and
the seedling may be removed with less danger of contaminating the
healthy plants. Protection against the insect carriers of this disease
may be effected by fumigation with hydrocyanic acid gas, but care
must be taken not to use the latter when any form of copper
sulphate treatment has been given. The wild cucumber (Micram-
pelis lobata) and the one-seeded bur cucumber (Sicyos angulatus)
are both hosts of mosaic and must not be allowed to grow in the
vicinity of the cultivated kinds.

Sclerotinia rot, which is stated to be most frequently introduced
with organic manure and disseminated by insects, may be controlled
by severing the infected laterals from the main stem and washing
the resultant wound in a 1 in 1,000 solution of corrosive sublimate.
Fusarium fruit rot may be suppressed by similar measures. Angular
leaf-spot, caused by Bacteriwm lacrymans, is said to be frequently
transmitted by pickers from diseased to healthy plants, and also by
insects, but the most important source of dissemination is the water
used for spraying the foliage. The disease is believed to be carried
on the seed, and treatment with a 1 in 1,000 solution of corrosive
sublimate is recommended. Powdery mildew (Evrysiphe cichorace-
aruim) is stated to be adequately controlled by spraying the plants
with a 1 in 40 solution of lime-sulphur.

The regulation of temperature and humidity is regarded as being
extremely important. The optimum temperature for the plants
ranges from 60° to 75° F. High humidity favours the develop-
ment of mildew, Sclerotinia, and Fusariwm rot, and thorough
ventilation is essential, even if the open windows necessitate a
greater expenditure of fuel. Thin-leaved varieties are liable to
sun-seald, followed, in severe cases, by attacks of Alternarza and
Cladosporium. Washing the plants with a fine mist of water on
sunny days is recommended as a preventive of this trouble.

OsBporN (T. G. B.) & SAMUEL (G.). Notes on two Vine diseases
which occurred on the River Murray in October, 1921.—
Journ. Dept. Agric. South Australia, xxvi, 3, pp. 225-230,
5 figs., 1922.

During the latter part of October, 1921, vine shoots showing
a die-back of the tips were submitted for examination to the
Laboratory of Plant Pathology at the University of Adelaide.
Two diseases were found to be involved, one of fungous and the
other of physiological origin.

The former, due to Aureobasidivm vitis, caused the blackening
and death of the tips of the shoots and a decay of patches of irregu-
lar shape on the leaves. Kept overnight in a moist chamber, the
leaves turned black all over and the surface became rather sticky,
minute, whitish dots simultaneously appearing on the affected parts,

153

Specimens sent in a few weeks later showed the fungus attacking
the young fruit bunches. Sections through the whitish pustules
revealed small heaps of spores, budded off from the fertile ends of
hyphae arising from the mycelium growing through the tissues of
the leaf. :

A. vitis was discovered in France in 1882, its occasional attacks
usually occurring in muggy weather and causing only slight losses.
The species has been sub-divided into several varieties, the South
Australian specimens agreeing most closely with Montemartini’s
var. album, both in the parts affected and in the nature of the
spore pustules.

The majority of the affected vines were young, one and two year
old plants, and there was a cover-crop of wheat growing between
the rows. Possibly the presence of wheat. helped to maintain the
humidity necessary for infection. The hot weather at the end of
October arrested the spread of the disease and the dead patches on
the leaves dried out. Where the shoot tip had been killed, numbers
of laterals sprang from below, making it difficult to secure good
canes to form the vines. Death occurred only in the case of one or
two vines which had very small shoots at the time of infection.
Cases of the disease occurred in several districts, the weather con-
ditions evidently being such as to induce a mild epidemic of what
is ordinarily a parasite of little importance.

The second disease, believed to be of physiological origin, occurred
in various localities along the Murray valley. Blackening and
death of the tips of the young shoots was occasionally noted, but
amore characteristic feature was a mottling due to the develop-
ment of small angular areas of a pale green or brown colour in the
leaves, producing a mosaic effect. Only three to five leaves on
a shoot were thus affected, those above and below being quite
healthy. The spots were usually more numerous near the veins.
The fresh healthy growth shown by many vines inspected some
three weeks after the first report of the disease indicated that the
causal agency had operated everywhere at about the same time and
then been completely removed. The development of the main shoot
was often considerably impeded, and it was sometimes outgrown by
strong laterals springing from the base.

All attempts to detect or isolate a fungous or bacterial parasite
failed. The pathological changes in the cells of the discoloured
areas—gummosis of the cell walls, rupture of some cells and the
secretion of oily substances in others—agree in the main with those
that follow injury by late frosts. The affected vineyards were all
situated on low-lying areas where the temperature probably fell to
freezing point about the time the injury occurred, while active
root absorption was maintained owing to the comparative warmth
of the soil. Possibly these conditions led to the pathological changes
noted above.

Brown (J. G.). Plant pathology. Thirty-second Ann. Rept. Ari-
zona Agric. Exper. Stat. for the year ended 30th June, 1921,
pp. 606-615, 4 figs., 1922.
The fungous diseases of the principal crops recorded in Arizona
D2

154

during the year are enumerated and those of special interest briefly
deseribed. .

A serious rot of dates [Phoenix dactylifera], which is likely to
cause trouble to Arizona date growers, is reported. It sometimes
causes the loss of 95 per cent. of the crop. The disease is charac-
terized by the appearance on the fruit either of minute, chocolate-
brown spots which eventually coalesce and cover one side, becoming
creamy-white in the centre, or of small, water-soaked areas which
finally unite to form a blister. In both cases the protective layers
of the fruit are ruptured, resulting in drying and mummification.
The mummified fruit may remain hanging to the clusters or may
drop. Both kinds of spots occur on the leaflets, and the brown
spots are also found on the petioles and on the stalks and branches
of flower and fruit clusters. Blistering does not take place on the
more woody organs.

Tsolations from diseased leaves and fruits gave several organisms.
Of these, species of Mucrosporium, Alternaria, and Helmintho-
sportum were shown by inoculations to be actively parasitic on the
unripe fruit. These fungi probably rupture the protective outer
layers of the fruit and leaves, thereby facilitating the admission of
secondary organisms. The hyphae pass through and between the
cells, which are killed rapidly. The tannin layer of the fruit
temporarily checks penetration towards the centre, but the hyphae
spread parallel with the surface, killing the outer parenchymatous
tissue and leaving a cavity under the cuticle and epidermis which
becomes filled with air and produces the blistered appearance
described above. After the formation of a blister, the surface soon
cracks enough to cause the mesocarp to dry out, and the hyphae
finally succeed in penetrating the tannin layer and thus reach the
endocarp.

The very valuable Deglet Noor variety is probably the most
susceptible to this date rot, but none is entirely immune. Fruit
clusters sprayed in 1921 with Bordeaux mixture 4—4-40 were free
from the disease at the time of writing.

Black arm and angular leaf spot (Bacterium malvacearwm) were
present in nearly every field of Pima-Egyptian cotton, the injuries
to the crop including stem lesions, destruction of leaf tissue, bol]
spotting, premature ripening, and fibre staining. Some fields were
practically ruined. The appearance of the attack supported the
view that the causal organism is carried by the seed. Arizona
cotton growers are unfortunately slow to adopt the method of seed
treatment [see this Review, i, p. 383] which has effectively controlled
this disease in the south. Experiments are in progress to ascertain
whether the large quantities of alkali in the cotton districts of
Arizona increase the susceptibility of the crop to Bact. malva-
cearum. Other cotton diseases recorded were sore shin caused by
Rhizoctonia [solani], wilt (Fusarium vasinfectum), and root rot
(Ozonium omnivorum).

A severe outbreak of bacterial rot of lettuce occurred in two
localities in the spring of 1921. The outer leaves of the head were
generally affected first, a brown discoloration of the veins and then
of the entire leaves ensuing, until the head was finally transformed
into a dark, slimy mass. One whole field of sixty acres was ruined.

155

Laboratory studies revealed the presence of two bacteria capable of
completely rotting healthy heads of lettuce within two or three
weeks. ‘lhe identity of the bacteria has not yet been established.
In the eastern states bacterial rot of lettuce has been attributed to
the use of poorly rotted manure, but in Arizona no fertilizers have
been used in the silt fields concerned. Ozoniuim omnivorum also
attacked this crop.

Grapes were affected by a new type of rot, the cause of which is
obscure. In this disease unripe fruits of white varieties are spotted
with soft, brownish, semi-translucent areas, which become bronzed
as shrivelling and rotting proceed, and later turn purple. Drying
progresses more rapidly on one side than the other, and the tissues
collapse so that the outline of the seeds can be distinguished. Often
the berry remains normally green except for one sunken spot.
Cultures from surface-sterilized fruit generally gave no growth,
except an occasional G/oeosporiwm with much larger spores than
those of any species hitherto reported on the grape.

There are numerous other records, mostly of common or well-
known diseases of crops and ornamental plants.

Annual Report, Department of Agriculture, Uganda, for the year
ended 31st December, 1921. 87 pp., 1922.

In addition to the Report of the Government Mycologist, which
is separately noticed [see next abstract], there are various references
to plant diseases of interest.

In the Report on the Government Plantation, Kampala, J. D.
Snowden states that coffee leaf disease (Hemileia vastatvix) was
extremely prevalent and exceptionally virulent on Coffea arabica
from June to August, a large number of the trees being’ entirely
defoliated for a time. Some varieties of C. robusta were also con-
siderably damaged by the disease. The most resistant of the
robusta types are Toro, Quilou, and three trees of C. congensis var.
chalottii, All the three varieties of C. excelsa that were grown
remained very resistant to leaf disease. C. liberica is also highly
_ resistant, but is less vigorous, and gives a lower yield than (.
excelsa.

Hevea rubber trees were attacked throughout the year by a
species of Oidiwm which caused a serious loss of young foliage.
‘Black thread’ [Phytophthora sp.| was less serious than in the
previous year, the percentage of affected trees being 18-33 as against
48-25. Most of the infections again occurred in series which were
being tapped near the base. Painting the infected parts with un-
diluted ordinary Brunolinum and the disinfection of the tapping
cuts with 2 per cent. Izal gave good results.

There were twenty-eight existing cases of brown bast disease of
Hevea in May and ten new infections were found to have occurred by
the following November. The important fact was noted that only
2-89 per cent. of the trees tapped on alternate days were infected,
as against 18 per cent. of those tapped daily. ‘Stripping’ for the
cure of the disease must be carried out at an early stage, as other-
wise the surface of the cambium becomes badly damaged by the
formation of nodules. The operation should be performed when
the foliage is just mature. Trees which are ‘ wintering’ or are full

156

of young foliage cannot be stripped without difficulty and risk of
injury.

re T Philpott reports that trees of Coffew arabica at the Govern-
ment Plantation, Kakumiro, Mubendi, were remarkably free from
Hemileia vastatriz until a severe outbreak occurred in the middle
of November. Costa Rica and Bourbon cottee trees, planted in 1918,
were severely attacked by root scale (Pseudococcus citri), accom-
panied by white root disease [Polyporus coffeae], and efforts to
control the combined attack have not been very successful so far.
White root disease is constantly recurring, and the use of hme or
some other soil sterilizer will probably be necessary to ensure
profitable coffee-growing on the Kakumiro Plantation.

SMALL (W.). Annual Report of the Government Mycologist for
1921.— Ann. Rept. Dept. Agric. Uganda, 1921, pp. 49-57, 1922.
The two best-known fungi on coffee in Uganda are Hemeleia
vastatria and Colletotrichum coffeanum [Glomerellu cingulata], but
the author points out that they are not the greatest enemies of the
crop. The former is not, under Uganda conditions, so harmful or
progressively weakening as had been expected, and spraying against
leaf disease is never attempted nowadays. Good cultural methods
can to a great extent neutralize the injurious effects of attack by
this rust. Colletotrichwm is not an aggressive parasite, but merely
a common saprophyte that can attack weakened bushes. The true
cause of die-back, when it occurs on a large scale, is lack of vigour
due to unfavourable conditions such as over-bearing, absence of
shade, weeds, and bad cultivation generally. Occasional direct
attacks of Colletotrichwm do occur, but are usually on a small scale,
and affect only a few branches or young twigs. The author recom-
mends that the term anthracnose, and not die-back, should be used
for the latter form of the disease.
The brown-eye spot (Cercospora coffeicola) of coffee leaves and
berries was more prevalent than in previous years, over 60 per cent.
of the berries being affected in some cases. The only root disease

of coffee reported was the white root disease caused by Polyporus »

coffeae, which has never been found as an independent parasite, but
at times accompanies the coffee root mealy bug, Pseudococcus citri.
Of considerable interest is the record of the appearance of the
powdery mildew (Oidiwm sp.) of Hevea brasiliensis in two localities
in Uganda. This disease, previously known only in the Dutch
East Indies, does not appear to be serious, causing only the death
of a few twigs and the deformation and loss of a few leaves. The
attack was typical of the published descriptions from Java. No
case of root disease of Hevea was reported, though both Ustulina
zonata and Fomes lignosus are known on other hosts in the colony.
Associated with orange rust of wheat (Puccinia triticina) is the
leaf spot fungus Leptosphaerva tritici, while a Helminthosporium,
provisionally named H. sorokinianum, is common. One case of
supposed downy mildew of maize [Sclerospora sp.] was encountered.
The leaf symptoms appeared unmistakable, though the causal fungus
itself was not found. Nosmuts have been found on this crop in
Uganda. Sorghum is attacked by head smut (Ustzlago reiliana) and
grain smut (Sphacelotheca sorghi), the latter being the more common.

——

157

Another disease of sorghum, downy mildew or green ear, was dis-
covered in July, 1921, at Bukalasa. The symptoms consist of a
whitening in streaks of the young leaves, followed by browning,
twisting, and erinkling. The oospores of the parasite | Sclerosporu
sp.] were found in the tissues of affected leaves, but they were only
half the size of the oospores of the fungus [Sclerospora gramini-
cola| which induces the similar disease in India.

Several diseases of shade, fruit, and ornamental trees and plants
are mentioned. Roses, Grevillea robusta, Melaleuca leucodendron,and
Spondias lutea are added to the list of hosts of the wet root rot fungus.
Further attempts to induce the latter to fruit in culture gave nega-
tive results. Albizzia moluccana, grown as coffee shade, succumbed
to attacks of Lotryodiplodia theobromae on the roots. The attack
probably begins on very small roots while the trees are quite
young; the fungus makes very gradual progress, and death occurs
just when the trees are beginning to be of use for shade purposes.
B. theobromae also causes a die-back of pruned branches of the
same host, and it is reeommended that the use of the latter as a
coffee shade tree should be abandoned. The leaves of fig trees were
severely attacked by Uredo fici [Kuehneola ici], and the fruit by a
species of Colletotrichum.

A report on an investigation into certain fungi occurring on
diseased rice in Uganda is appended. Specimens of diseased rice
collected in 1920 were reported by the Imperial Bureau of Mycology
to bear the following fungi: Piricularia oryzae, Helminthosporium
oryzae, Leptosphaeria michotit, Gibberella saubinetii, Graphiwm
stilboideum, and Fusarium rosewm. The following further fungi
have been noted on rice material: Phoma glumarum, Epicoceum
hyalopes, and Melanospora zamiae. Of these fungi G. saubinetii
had not previously been recorded on rice, and Piricularia oryzde
was reported for the first time from Africa.

The writer carried out an investigation on the part played by
these fungi in the disease in question, and found that the whole of
the damage could be attributed to P. oryzae. He states that only
one major disease of rice is at present known in Uganda, namely,
the well-known ‘blast’ of this crop. Further specimens of G. saubi-
netii were not obtained in any case, and the Fusarium commonly
present on diseased plants is regarded as not belonging to this
fungus. Inoculations with it on young rice, wheat, and maize
failed to produce any effect.

An account of the author’s studies on another species of Fusarium,
which causes a wilt of various plants, has been separately published,
and is noted elsewhere [see below, p. 163].

Wo tr (F. A.). Studies on fermentation of rare sugars by plant
pathogenic bacteria.— Journ. Elisha Mitchell Sci. Soc., xxxviii,
1-2, pp. 12-13, 1922.

Different species of pathogenic bacteria from the same host may
be indistinguishable on the basis of their ability to ferment the
carbohydrates of the Descriptive Chart. The fermentation of rare
sugars has, therefore, been used as a means of identification of
certain closely related organisms. Bacterium tabacum and B.angu-
latum, the causal agents of wildfire and angular leaf spot of tobacco

158

respectively, are both able to form acid from dextrose and saccharose,
but not from glycerine and lactose. The former, in addition, attacks
manitol and galactose, while the latter does not affect them. A
similar specialization obtains in the case of two leaf spot organisms
of soy-bean, Bacteriwm glycinewm and B. sojae.

RosEn (H.R.). The bacterial pathogen of Corn stalk rot.— Phyto-
path., xii, 10, pp. 497-498, 1922.

Bacterial stalk rot of maize [see this Review, i, p. 170], first
described from Arkansas, and now reported from about eight
different States, is caused oy Pseudomonas dissolvens n. sp., which
is briefly characterized as follows. Short, plump, rapidly growing
rods, motile by means of a single polar flagellum, bluntly rounded
at both ends, occurring singly, in pairs, or occasionally in short
chains, 0-7 to 1:2 by 0-5 to 0-9, capsules present, colonies on
nutrient agar poured plates (testing Py 7-0) round, margins entire,
white, opaque, glistening, consistency of melted butter, smelling
strongly of decaying vegetable matter. Gelatine and Loefiler’s
blood serum not liquefied; acid and gas produced on most nutrient
media; diastatic action perceptible ; indol and ammonia produced ;
nitrates reduced; coagulation of milk marked on sixth day;
growth in Uschinsky’s solution good. Index number, according to
the most recent chart of the Society of American Bacteriologists
(1920), 5822-32220-1111.

SrakMaN (E. C.) & Levine (M.N.). The determination of biologic
forms of Puccinia graminis on Triticum spp.— Univ. Minne-
sota Agric. Exper. Stat. Tech. Bull. 8, 8 pp., 1 fig., 1922.

It has been shown by the present writers and others that Puc-
cinia graminis triticc (Pers.) Eriks. & Henn. really consists of
several biologic forms recognizable by their action on different
varieties of wheat (’riticum vulgare, T. durum, T. compactum),
emmer (7. dicoccwm), and einkorn (TL. monococewm). A method
has been developed for the identification of the thirty-seven biologic
forms now known, by their parasitic action on a selected group of
varieties of Triticum. Little Club is susceptible, and Khapli highly
resistant, to all the known forms of the rust.

Twelve ‘differential hosts’ of the groups referred to above are
inoculated and incubated for 48 hours, the best results being
obtained by keeping the plants under optimum conditions for rust
development. Plenty of sunlight is essential. The types of infee-
tion are indicated by numerals from 0 to 4, the former being
equivalent to practical immunity, and the latter to complete sus-
ceptibility. Fluctuations within a class are designated by plus and
minus signs. Plants on which the degree of attack, as judged both
by the number of sori and their size and other characters, ranges
from 0 to 2 are marked immune, very resistant, and moderately
resistant respectively, while those infected in the degrees of 3 and 4
are designated moderately susceptible and very susceptible. In
addition to these five types, a sixth occurs when certain biologic
forms are inoculated on some varieties of wheat. In this type
various degrees of infection may occur apparently ranging from 1
to 4,and with all types of sori on the same leaf. Such hetero-

159

geneous types of infection are placed in a separate group X, and
have to be very carefully distinguished from cases of mixed infection
by two or more strains of the rust.

An analytical key is given by which each of the thirty-seven
biological forms of the fungus can be recognized by its behaviour
when inoculated on the differential hosts in a certain definite order.

WEBER (G. F.). Septoria diseases of Cereals. 1. Speckled blotch
of Oats caused by Leptosphaeria.—Phytopath., xii, 10, pp.
449-470, 2 pl., 5 figs., 1922.

Speckled blotch of oats, caused by Septoria avenae Frank, occurred
to a limited extent on volunteer oats near Madison, Wisconsin, in
September, 1921. Hitherto the disease (which is distinct from that
caused by Septoria gramineum var. C. avenae Desm.) was only
known in England and Germany. The Septoria lesions were rather
small, circular to elongate, elliptic, killed and faded areas, 2 to 4 by
2 to 8 mm. in size, and distinguished by the black, more or less
scattered pycnidia.

The fungus was isolated and single spore cultures on oatmeal
agar and potato agar yielded perithecia with mature asci in 1922,
as well as pycnidia. Single ascospores were transferred to culture
tubes, and gave rise to pycnidia and later perithecia. Inoculations
of oat seedlings with ascospores also gave typical Septoria spots.
From this it is clear that the ascigerous stage of Septoria avenae
has been found. It is a new species belonging to the genus Lepto-
sphaeria, and the author names it L. avenaria, adding a full
description.

The pathogenicity of the organism was completely proved by
re-isolating it from artificially infected spots. The results of inocu-
lation experiments showed that whilst no infection occurred on
hosts other than Avena, the following species besides A. sativa were
susceptible: A. barbata, A. brevis, A. fatua, A. nuda, and A.
strigosa.

Detailed cultural and germination studies are described ; cultures
of germinating ascospores in dilute Indian ink revealed the presence
of a gelatinous sheath round the spore and the older portions of the
germ-tubes, which sheath may play an important role in infection.
The cardinal temperatures for mycelial growth on agar poured plates
are as follows: minimum 2°C., optimum 20° to 25°C., and maxi-
mum 32°C. The fungus grows best on a slightly acid medium ;
development was retarded at H-ion concentrations lower than Py 3-8
and higher than P, 7-0.

The method of infection was studied, and it was found that both
pycnospores and ascospores lodge in the furrows between the epi-
dermal cells and there develop germ-tubes, the tips of which apply
themselves to the cuticle directly above adjoining walls of the epider-
mal cells. The infecting hyphae penetrate the cuticle, and grow down
between the epidermal cells, after which they develop intercellularly,
no haustoria being found. Pyenidia form below the stomata where
the hyphae collect and become matted together.

The incubation period is from twelve to sixteen days, the first
symptoms of infection (light-coloured spots on the leaves) being
noticeable on the eighth or ninth day. The pyenospores remain

160

viable over winter when retained in the pyenidia. On Ist April,
1922, 90 per cent. of the spores from diseased oat leaves collected
in the previous September germinated.

Duc (L.). L’ergot du Blé dans Ain. [Ergot of Wheat in the Ain
Department.|—Journ. Agric. Prat., |xxxvi, 43, pp. 360-361,
1922.

In July 1922 the writer observed a 4-hectare field of wheat in
the Ain Department in which there was a severe attack of ergot
[Claviceps purpurea], confined to one variety (Carré Vaudois) of
the five varieties cultivated in the field.

Clean seed was stated to have been used, but it was not treated
with any fungicide before sowing. The presence of ergot could
not be detected on grasses in the neighbourhood, nor did it occur
on another field of Carré Vaudois a few miles distant. Reports of
ergot on barley have been received from two localities in the same
district.

The length of the sclerotia at harvest varied between | and 2 cm.,
the maximum weight was 155 mg., and the average weight of 10
was 22 gm. About one ear in every ten was infected.

ScHAFFNIT (E.). Zur Bekampfung der Pilzkrankheiten des Ge-
treidekorns. [On the control of fungous diseases of cereals. |—
Mitt. aus dem Inst. fiir Pflanzenkrankheiten der Landwirt-
schaftl. Hochschule Boun-Poppelsdorf, in Landw. Jahrb., \vii,
2, pp. 259-283, 1922.

In this paper the author discusses a large series of trials of fungi-
cides for the disinfection of seed grain, including several recently
introduced proprietary preparations, and also considers the influence
of certain external factors on the incidence of cereal diseases.

Copper sulphate and formaldehyde, until recent years the two
principal disinfectants of seed grain, are open to the serious objec-
tion of reducing or retarding germination. This defect becomes
marked not only when the prescribed strength of the solution or
duration of immersion is exceeded, but also when atmospheric con-
ditions or the factors influencing physiological activity are un-
favourable, and, generally, in the case of exotic or delicate varieties.
Formaldehyde injury was considerable in experiments during the
autumn and winter of 1920-21, when the low temperature combined
with scanty rainfall set up unfavourable conditions. In a plot of
winter wheat treated by immersion in 0-2 per cent. formaldehyde
for 74 minutes, only 156 seedlings came up as against 1,048 in the
control. Tests showed that there was no appreciable reduction in
the germination power of the treated grain for a fortnight after
immersion, so that it was evidently a case of delayed injury. Form-
aldehyde penetrates through the peripheral layers of the embryo
either in aqueous solution or as a gas, and can destroy the cells of
the coleorrhiza and even the entire embryo. In the former case
the development of the radicle is prevented and the seedling is
obliged to form adventitious roots. This explains the frequency
of delayed germination after formaldehyde treatment. Phenol and
codein were both found to be present in April, 1921, in the un-
germinated seed sown the previous September. Formaldehyde

161

injury is stated to have been very general in the Rhine provinces
during the period referred to.

At the Bonn Agricultural College tests were made of formalde-
hyde, fusafine, corbin, kurtakol, uspulun, phenolsulphonic acid
mercury sulphate, 777, and 778 in 1919-20; and of chinosol, form-
aldehyde, fusafine, germisan, kurtakol, uspulun, and weizenfusariol
in 1920-21.

Against bunt of wheat [Tilletia tritict] the best results were
given in the spring wheat crop of 1920 by fusafine (0-25 per cent.
for 30 minutes), the treated crop having only 0-04 per cent. bunted.
Uspulun gave 0-12 per cent.; formaldehyde, 0-14; 778, 0-34; 777,
0-63; corbin, 0-69, and the rest over 1 per cent. « Corbin and 777
caused the most severe seed injury. With winter wheat in 1920-21
germisan (0-25 per cent. for 1 hour) gave the best results, completely
eliminating the disease. Formaldehyde, as already stated, caused
very great seed injury. Weizenfusariol gave 0-34 per cent. bunt,
uspulun 0-79, and both these preparations stimulated germination.
On the spring wheat in 1921 uspulun and germisan, used in solu-
tions of 0-25 per cent. for 1 hour, gave respectively 0-43 per cent.
infection and complete control, the former being slightly the better
in regard: to the number of plants and ears in the plot. Germisan
has been found to impede germination for the first ten to fifteen
days, after which the plants quickly make up for lost time.

Against the fusariose of rye [presumably Fusarium nivale (Calo-
nectria graminicola)| germisan, uspulun, and kurtakol were used
in 1920-21. The first two completely eliminated the disease, and
the seed showed good germination and subsequent growth, especially
after uspulun. Kurtakol was ineffective.

Winter barley was treated in 1919-20 against stripe disease
| Helminthosporium graminewm], when corbin and chinosol com-
pletely prevented the disease but seriously impaired germination,
while uspulun reduced infection to a trace and at the same time
had a stimulating action. In 1920-21 germisan gave complete
control and uspulun 1 per cent. disease. }

Against covered smut of barley [Ustilago hordez| and loose
smut of oats [ Ustilago avenae| the preparations that have given
the most complete control so far are formaldehyde, copper sulphate,
and weizenfusariol. The first two are, however, open to the objec-
tions mentioned above. Uspulun has not been very satisfactory,
probably because it does not penetrate between the glumes
sufficiently to reach all the spores.

Summarizing the results of the tests in 1920-21 the author states
that formaldehyde is very effective against bunt and considerably
reduces the stripe disease of barley ; it is not so effective against
Fusarium. Its general value is much lessened by its injurious
secondary action on the grain. The same criticism is applicable to
copper sulphate and chinosol. The colloidal copper preparation,
kurtakol, is effective against bunt but is worthless for checking stripe
disease or fusariose. Fusafine and weizenfusariol are also useful
against bunt but worthless against stripe disease. Phenolsulphuric
acid mercury sulphate has no value in the control of these three dis-
eases. Corbin controls bunt and stripe disease but causes an excessive
reduction in germination capacity. Uspulun effectively controls all

D3

162

three diseases. Germisan, however, is, on the whole, the best of the
preparations tested against these cereal diseases, its only defect
being the retarding action on germination. A new modification of
it, germisan T.B.S. 12, appears to have surmounted this difficulty.

The fungicidal action of germisan, uspulun, and KK10 was
tested on spores of Tilletia tritici and Ustilago hordei. The
strengths used ranged from 0-03 to 0-25 per cent. and the period
of immersion from 5 to 50 minutes. It was found that uspulun
requires a minimum concentration of 0-25 per cent. to kill the
spores of 7’. tritzci and of 0-12 per cent. for those of U. hordet.
With germisan the 0-12 per cent. concentration suffices for both, so
that in their germicidal effect on U. hordei there is little difference
between the two. KK10, in which the CH, group of the benzene
nucleus is replaced by an atom of chlorine, was found to be more
powerful than the commercial germisan.

With regard to the influence of factors affecting the growth of
the host on infection by Villetia tritici, the author points out that
the temperature during germination, the supply of plant nutrients in
the soil, the physical condition of the latter, and the physiological
activity of the seed after planting, all have to be considered. His
observations support the work of earlier investigators who found
late autumn and early spring sowings tend to increase bunt, since
the temperature approaches the minimum for the germination of
wheat and the susceptible period is prolonged. But the correlation
between the rate of germination and susceptibility to smut requires
further investigation. Good soil moisture, the use of nitrogenous
fertilizers, and a loose texture of the soil favour rapid germination
and are stated to reduce liability to these diseases.

In some experiments on the influence of nutrition on susceptibility
to disease the author found that heavy nitrogenous manuring pre-
disposed to the attack of Hrysiphe gruminis, but that Colletotrichum
lindemuthianum did not seem to be in any way influenced by the
nutrition of the host. His field observations do not support the
statement frequently made that excessive nitrogen predisposes to
the attack of Puccinia glumarum, except in so far that it
prolongs the period of vegetative growth during which the plant is
susceptible to injury by rust.

BREDEMANN (G.). VWersuche tiber Erhéhung der Keimkraft unserer
Hanfsaat durch Beizung. [Experiments in the increase of
the germinating power of Hemp seed by steeping. |—Faser-
forschung, ii, 1, pp. 58-63, 1922.

In 1920 the investigations of the German Hemp Cultivation
Society showed that scarcely half of the home-grown and imported
Italian seed of hemp [Cannabis sativa] examined possessed the pre-
scribed germinating power of 90 and 70 per cent. respectively.
Experiments were accordingly undertaken in 1920 and 1921 to test
the value of uspulun as a stimulus to germination. In the first series
of tests (1920) the effect of steeping in uspulun (0-25 per cent. for
one hour) was remarkable, the average result of five outdoor experi-
ments with Italian seed being that for each 1,000 plants from
untreated seed there were 2,254 from the seed treated with uspulun.
In ten experiments with German (Russian) seed the lots treated

163

with uspulun gave 1,086 plants for each 1,000 from the untreated
controls.

In 1921 the experiments were continued at the Agricultural
Research Station of Landsberg-an-der-Warthe on a more extensive
scale with Italian, Chile, and German (Russian) seed. It was shown
that treatment with uspulun (same strength as before) increased
the germinating power of the seed by 25 per cent., while immersion in
water alone reduced it by 7 per cent. Thus with a seed rate allow-
ing for an average stand of 80 plants per square metre on normal
germination, steeping in uspulun produces 200,000 stems more per
hect. It has not yet been ascertained whether the action is
due solely to the known stimulating effect of uspulun, or if its
fungicidal properties are also involved. In any case it can be
highly recommended to hemp growers as a practical and reliable
means of increasing the yield from poorly germinating seed.

SMALL (W.). On the occurrence of a species of Fusarium in
Uganda.—Kew Bull. Misc. Inform., 9, pp. 269-291, 13 figs.,
1922.

The species of Fusarivwm previously described by the author from
Uganda [Kew Bull., p. 321, 1920] as causing a wilt of carnations,
Delphinium, Nigella, and Cosmos, has since been found attacking
other plants, among which are included Antirrhinum, seedlings of
the cashew-nut (Anacardium occidentale), Grevillea robusta, Eu-
genia jambos, and the loquat (Eriobotrya japonica). On carnations
and Antirrhinuim it is sometimes associated with Heterodera radici-
cola and the author believes the latter is the primary parasite in
the case of the Antirrhinum, the Fusarium having on this host
a degree of parasitism so feeble that it was only just removed from
saprophytism.

The attack on the cashew-nut seedlings takes the form of a
severe wilt which is fully described and which, in some cases, was
observed to kill up to 100 per cent. of the seedlings. Of the other
hosts named Grevillea is next in order of susceptibility, while
Eugenia and the loquat are but little damaged.

A full description is given of the cultural characters of the fungus
on various media, as well as of a large series of cross-inoculations
on the different hosts. From its morphological characters and the
fact that he succeeded by inoculation with his organism in induc-
ing a wilt of the pigeon pea (Cujanus indicus) similar to that
described by Butler in India, the author provisionally identifies the
Uganda fungus with Fusariwm udum Butl.

Snow (LartitIA M.). A new host for the fire blight organism,
Bacillus amylovorus.— Phytopath., xii, 11, pp. 517-524, 1922.

In this paper the author first gives an exhaustive account of all
records from 1793 onwards of the host plants affected by fireblight.
Up to the present the organism has been shown to be able to infect
the following hosts: pear, apple, quince, service berry (A melanchier
canadensis), English hawthorn (Crataegus oxyacantha), evergreen
thorn (Crataegus pyracantha), wild crab (Pyrus coronaria),
cultivated crab, Cheney plum (Prunus americana nigra), apricot,
prune, and strawberry. Burrill’s statement that the Lombardy

164

poplar is attacked is questioned, and the reports for other hosts
appear to rest upon observational evidence only. :

In establishing the ornamental shrub Prunus triloba var. plena
as a new host for Bacillus amylovorus, a number of isolations were
made from plants growing at Wisconsin, and two of these were
selected for comparison with an isolation from the crab apple and
a laboratory stock culture. The morphology and culture reactions
of all these strains agreed and are described in detail. They also
agreed, in the main, with the reactions quoted by other investi-
gators, but the following exceptions may be noted. In the nitrate
reduction test no nitrogen was evolved and no nitrates formed, but
a moderate amount of ammonia was produced. After prolonged
cultivation the power to digest casein was lost and the organism
gave corresponding slight or no liquefaction of gelatine. No indol
was formed.

All the strains developed a peculiar odour, which has been
variously described and is difficult to characterize. Both strains
isolated from the new host were pathogenic on the pear at first but
lost their virulence after cultivation. The laboratory strain was
non-pathogenic, whilst that from the crab remained strongly viru-
lent after two years.

A bibliography of 34 titles is appended.

Herpert (D. A.). Bitter pit of Apples. The crushed cell
theory.—Phytopath., xii, 10, pp. 489-491, 1922.

McAlpine’s bursting cell theory of bitter pit in apples is not
altogether supported by the writer's investigations.

It is generally admitted that the fluctuation in water supply is
the primary cause of bitter pit, the point in question being in what
manner the diseased patches are produced. The rush of sap to the
apple after a fall of rain following a dry spell causes a distension
of the parenchymatous pulp cells. If the cells in any particular
pit area were to swell to bursting-point, wart-like bodies would be
expected at affected points instead of depressions. In Dunn’s
Seedling the flow of sap after a rain is sometimes sufficient to burst
the skin, but no bursting of the cells takes place within the apple.
It is difficult to see how such bursting could occur in bitter pit, as
the expansion of adjacent cells would bring the tissue into a state
of static equilibrium and the only relief for the increased pressure
would be a bursting of the skin or a crushing of some of the cells.
Further an osmotic pressure of 100 atmospheres entirely borne by
the cell may induce bursting, but this is immensely beyond any-
thing occurring in the cells of the apple.

The vascular tissue may frequently be traced through a pit and
found to be supplying healthy tissues beyond, which would not be
the case if the vascular network were ruptured.

Pitting generally occurs at the time when the starch is under-
going conversion into sugar, and the theory is advanced that the
affected cells have been killed by being crushed by neighbouring
cells having higher osmotic pressure due to their higher proportion
of sugar. With the sudden rush of sap to the apple, the cells
which have already had their starch-contents converted into sugar
will swell more extensively and rapidly than those still furnished

——

165

with starch. On the outside the rapid distension of the cells is
resisted by the skin. Their force of expansion results in the crush-
ing of those cells of which the starch transformation is backward.
This explains the presence of quantities of starch in the dead pit
cells.

The immunity from bitter pit of such varieties as Yates may be
due to the uniform transformation of the starch to sugar through-
out the tissue. In such cases there would be no small clusters of
cells far enough behind in their starch transformation to be crushed
by neighbouring cells of a higher osmotic pressure.

CUNNINGHAM (G. H.). Brown rot, Sclerotinia cinerea Schroet.
Its appearance, cause, and control.— New Zealand Journ. of
Agric., Xxiv, 8, pp. 83-98, 8 figs., 1922.

Brown rot is common throughout New Zealand except in Central
Otago, where it is apparently unknown. Since 1915 the disease
has been most destructive, and is now the most serious of all
fungous diseases on stone fruits, occasionally attacking also apples
and pears.

In New Zealand the causal organism of brown rot is Sclerotinia
cinerea Schroet., the related fungus SN. fructigena not having been
found as yet. Apothecia from mummied fruits are produced only—
during the blossoming period and when they are not covered by
more than an inch of soil. The disease usually appears first on
the blossoms, infection occurring before the petals unfold or shortly
after they have opened, and the period of infection extends from
the beginning of September to the end of October. A wet season
following a cold winter is usually accompanied by blossom infection.
Asa rule only a small percentage of blossoms is attacked, though
in exceptional cases all have been killed. Blossom infection may
be directly followed by infection of the developing fruits, but
usually the latter only takes place at the time of maturity of the
fruits. The formation of cankers and the dying back of the shoots
are described.

On the leaves the fungus produces small, brown, more or less
circular, dead areas, which may later fall away, leaving perforations
similar to those caused by shot-hole fungi. In extreme cases the
leaves are killed and fall prematurely, and the following season’s
crop may be reduced by this cause.

The successful control of brown rot is only possible when rigid
orchard hygiene is practised. In addition the following sprayings
are recommended: (1) when the buds begin to swell, Bordeaux
5—4—50 or lime-sulphur 1-15 [also useful in the control of leaf-curl
(Exoascus deformans)|; (2) in early pinking, lime-sulphur 1-50;
(3) petal-fall, lime-sulphur 1-120; (4) one month later, lime-sulphur
1-120; (5) when fruits are half-grown, lime-sulphur 1-120;
(6) immediately before maturity, lime-sulphur 1-120, The sterili-
zation of fruit cases may be effected by immersing them for one
minute either in boiling water, copper sulphate solution 1-100,
lime-sulphur solution 1-50, or formalin solution 1-40, Tins may
also be immersed in any of the above solutions, except copper
sulphate.

166

Wriygcier (H.). Behandlung stark befallener 4lterer Pfirsich.
spaliere. [Treatment of severely infected old espalier Peaches. |
—Deutsche Obstbauzeit., xviii, 41, p. 375, 1922.

A row of espalier peaches 100 m. in length at Bechau (Upper
Silesia) was so severely attacked by leaf-curl [ Hxouscus deformans]
and cochineal insects that the entire harvest was destroyed and
many branches had to be removed. An examination of the soil,
which was exceedingly hard and deficient in lime, indicated that
malnutrition was a predisposing factor in the severity of the
attack.

After removing all diseased material and thoroughly scraping
the trees with wire and other brushes, the trunks and main
branches were sprayed with a mixture consisting of loam, cattle-
manure, and lime in water, to which was added 2 per cent. of fruit
tree carbolineum. Early in March another application of carbo-
lineum was given (200 gm. to 10 1. of water) to destroy any re-
maining spores. During the winter the soil was cultivated to a
depth of 1 m., care being taken not to injure the roots, and fertilized
with horn splinters, basie slag, 45 per cent. potassium salt, and
a quantity of lime.

The trees were then sprayed with colloidal liquid sulphur (5 gm.
to 10 1. water), the first application coinciding with the swelling of
the buds and the second being given immediately before flowering.
From the setting of the fruit till about three weeks before ripening
applications were given every fortnight, always in the evening and
in dull weather. The total consumption of sulphur amounted to
100 to 125 gm.

The trees were completely cured, the shoots being vigorous and
the yield on the whole excellent. Peaches under glass were treated
in the same way and gave even better results.

CirERRI (R.). Una rara malattia delle fogliedel Susino. [A rare
disease of the leaves of the Plum.]—Riv. Pat. Veg., xii, 5-6,
pp. 59-64, 1922. ,
At Macerata in Italy the under side of some leaves of a plum
tree (variety ‘Luther Burbank’) were found to bear small, puncti-
form, dirty white, waxy pustules, at first discrete, but later coalescing
to a single, large, slightly raised mass surrounded by small, scattered
pustules. Corresponding with these, on the upper surface, irregular,
whitish areas occurred, the pale colour being due to the separation.
of the epidermis from the palisade parenchyma by a layer of
mycelium.
The fungus was identified as Microstroma tonellianum Ferraris,
a species that difters from M. platani Eddelbeuttel & Engelke more
biologically than morphologically. The conidiophores resemble
basidia so closely as to justify the doubt whether the fungus should
not be referred to the Basidiomycetes (Exobasidiales) rather than
to the Mucedineae. Like other species of the genus, such as @.
album (Desm.) Sace. and M. juglandis (Bér.) Sacc., the present
species diverges from the Mucedineae in the crust-like nature of
the hymenium, which is covered with abundant spores adhering to
one another, and also in the mycelial aggrevations found especially
beneath the epidermis as in many of the Exobasidiales. The

167

manner of invasion of the leaf, with the formation of fructifica-
tions on the opposite side to that attacked, is not common in the
Mucedineae. Finally the author states that he has observed clamp-
connexions such as are present in the Basidiomycetes. The fungus
is considered to have affinities with Avwreobusidiun vitis var.
album Montem., ditfering chiefly in the characters of the spores and
in the fact that they are not borne laterally on the basidia. The
absence of any hypertrophy of the leaf, so characteristic of attack
by many species of Lxobusidiwm, is noted.

In discussing the systematic position of the genus Microstroma,
the author states that Patouillard first united in the genus Hxoba-
sidiwm both Aureobasidium and Microstroma, the latter as a sub-
genus. Later on, however, he considered Microstroma to be a lower
form of the genus Helostroma of the Stilbaceae. Saccardo questions
whether the latter is not the perfect Hymenomycetic form of
Microstroma. Schroeter regards the genus as belonging to the
Basidiomycetes, and this opinion is shared by Brefeld and Hennings.
Briosi and Cavara refer M. albwm to the Mucedineae, with some
doubt whether it may not be regarded as belonging to the Tuber-
culariaceae or Stilbaceae on the strength of the pseudostipitate
type of conidiophore and the verticillate disposition of the conidia.
M. juglandis is, however, referred by those authors to the Melan-
coniales because of its sporogenous stroma developed in the sub-
stomatal chamber. This species is placed in the Mucedineae by
Lindau and Niessl, while the same view is taken in regard to M.
platani by Saccardo, Eddelbeuttel, Engelke, Ferraris, and Tonelli.

As to the damage caused by M. tonellianuwm the author thinks it
unimportant and capable of control, if necessary, by spraying with
Bordeaux mixture and by the destruction of affected leaves.

Cirerri (R.). Il marciume delle Mele Cotogne. [Rot of Quinces. |

—Riv. Pat. Veq., xii, 1-2, pp. 12-17, 1922.

This rot, which is due to Penicilliwm crustacewm (L.) Fries
(= P. glaucum Link), occurs on stored quinces in several regions
of Italy, when conditions of moisture are favourable. It is a
facultative parasite and is known to cause the rotting of a number
of fruits, though the author thinks that it has not been previously
reported on quinces. On these it behaves strictly as a wound
parasite, being able to infect sound fruit through*any cut or
abrasion of the skin, however slight, provided the moisture con-
ditions are suitable.

In relatively high summer temperatures the green mould on the
surface of infected fruits bore here and there small, black, roundish,
raised, isolated bodies, having a diameter of 200 to 300 yw, which
were at first taken for the sclerotial form of this fungus described
by Brefeld. These were found, however, to be merely dense aggre-
gations, dark green in colour, and composed chiefly of conidia 3 to
3-5 gw in diameter. Similar conidial aggregations are sometimes
found in cultures of various species of Penicilliwm. The author
also observed, but more rarely, the form which, described by Cesati
under the name of Sporisoriwm maydis, was referred by Saccardo
to the genus Chromosporiwm as C. naydis. This is nothing more
than the same Penici/liwi with the conidia more or less variously

168

arranged on the mycelinm, without specialized conidiophores. The
pseudosclerotia just mentioned are only an extreme development
of this form. Another form, rather frequent on old rotted fruits,
produces a pseudosynnema of the Stilbaceous type, $ mm. broad by
about 1 mm. high, bearing at the top a green head consisting of
a mass of conidia. This structure is formed by numerous, slightly
or not branched, rather densely fasciculated conidiophores, which
vary in length but usually are very long, and average about 3 yw in
diameter, and which are almost always sterile except at the free
end, where there is a copious production of conidia.

As preventive measures the author recommends the rejection of
all fruit showing the slightest lesion, the provision of dry storage
rooms, and care in not placing the fruits in contact with one
another.

Lyncu (W. D.), McDonNELL (C. C.), HAywoop (J. K.), QUAINTANCE
(A. L.), & Watre (M. B.). Poisonous metals on sprayed fruits
and vegetables.— U.S. Dept. Agric. Bull. 1027, 66 pp., 1922.

In 1915 a comparative study was undertaken by the United States
Department of Agriculture to ascertain the amounts of arsenic, lead,
and copper remaining on fruits and vegetables treated with poisonous
_ sprays. ‘The spraying was done under the direction of the Bureaus
of Entomology and Plant Industry, and the chemical work by the
Bureau of Chemistry. Various fruit trees and vegetables, including
peaches, plums, cherries, cranberries, grapes, apples, pears, tomatoes,
celery, and cucumbers, were sprayed according to accepted schedules,
and also with excessive amounts of material, to determine how
much of the metals may be present under adverse conditions,

It was found that overspraying or late spraying sometimes
resulted in comparatively large quantities of spray residues; nearly
all such residues, however, were removable by peeling. When the
spraying was carried out in accordance with the recommended
schedules, the quantity of metal adhering to the fruit or vegetables
at harvest time was negligible.

The work of previous investigators is discussed at considerable
length in the earlier part of the bulletin, which contains many
references to the history of fungicidal and insecticidal sprays. A
bibliography of 134 titles is appended.

Horron (E.) & Sautmon (E. S8.). The fungicidal properties of
certain spray-fluids. III.—Journ. Agric. Science, xii, 3,

pp. 269-279, 1922.
As a preliminary to a study of the exact fungicidal value of
a mixture of lime-sulphur and arsenate of lead, the writers carried
out in 1921 two series of spraying experiments: («) with solutions
containing arsenic acid, (/) with lime-sulphur and its constituents.
The fungus experimented on was Sphaerotheca huwmuli, and the
stage selected for spraying was the powdery, conidial stage found
on young leaves from the 3rd to the 9th node of rooted cuttings of
hops (Humulus lwpulus) grown in an unheated greenhouse. The
results of the arsenate tests showed that, under the conditions of
the experiments, disodium arsenate containing 0-096 per cent.
As,O, was fungicidal, and also killed the leaf-cells underlying the

169

mildew patches, but did not otherwise injure the leaf: a solution
containing 0-02 per cent. As,O, was fungicidal without killing any
leaf-cells. Trisodium, dicalecium, and tricalcium arsenates, at the
concentrations of 0-077, 0-048, and 0.076 per cent. As,O, respectively,
proved fungicidal: the latter two at concentrations of 0-024 and
0-02 per cent. respectively were apparently just fungicidal, and at
concentrations of 0-01 per cent. they were practically without
action.

In the lime-sulphur experiments 1 per cent. calcium caseinate,
which from tests appeared to be non-fungicidal, was added to the
spray solutions to increase their wetting powers and permit more
accurate results to be obtained. ,

The following constituents of lime-sulphur were found to be non-
fungicidal ; calcium sulphate, sulphite, thiosulphate, and hydroxy-
hydrosulphide; calcium polysulphide was the only constituent of
lime-sulphur, at the strengths at which the solution is used in prac-
tice, found to be fungicidal. A lime-sulphur solution 1 in 149,
containing 0-11 per cent. of polysulphide sulphur, was completely
fungicidal.

Full details of the materials used and a bibliography of 20 titles
are given.

Rreum (E.). Die Versuche des deutschen Pflanzenschutzdienstes
zur Priifung von Pflanzenschutzmitteln. [The experiments
of the German Plant Protection Service in testing preparations
for plant disease control.]—Nachrichtenbl. deutsch. Pflanzen-
schutzdienst, ii, 7, pp. 50-51, 1922.

Until 1919 tests of new methods of combating plant diseases were
undertaken by the individual experiment stations, and the results
were published in occasional reports. Different stations frequently
differed in their recommendations, both as regards the merit and
the methods of application of the same remedy. The resulting
confusion led to a centralization of the experiments, organized by
the Executive Committee of the Plant Protection Service in the
autumn of 1919. Since that time numerous tests have been made
of disinfectants for bunt of wheat [Tilletia triticz], stripe disease
of barley | Helminthosporium graminewm], and loose smut of oats
|Ustilago avenae|. Experiments have also been conducted in the
control of gooseberry mildew [Sphaerotheca mors-uvue], apple and
pear scab [Venturia inuequalis and pirina], and late blight of
potatoes [Phytophthora infestans],

The tests are carried out in the same manner in each of a number
of different centres, and preparations are not tested unless they
have been already tried and approved by at least one of the chief
stations for plant protection. Some 69 preparations are under trial
in the current year.

SNELL (K.). Beizungsversuche mit Trypaflavin. [Disinfection
experiments with trypaflavin. |— Nachrichtenbl. deutsch. Pllan-
zenschutzdienst, ii, 7, p. 55, 1922.

Tests were carried out in 1921 to ascertain whether the yield of
potatoes could be increased by steeping the tubers in ‘ trypaflavin’,
a preparation manufactured by the firm of Leopold Cassella & Co.

170

of Frankfort. The varieties selected for the test were Prof. Maercker
and Daber. The results obtained were not satisfactory, the yield
from the rows treated with trypaflavin not being equal to that
from the untreated controls. The yield from tubers steeped in
diaminoacridine sulphate and diaminoacridine nitrate, other pre-
parations received from the same firm, exceeded that obtained from
the rows treated with trypaflavin, but was still not equal to the
controls. Trypaflavin was not found to possess any decided fungi-
cidal properties as judged by the amount of scab, &c., on the tubers
from the treated seed.

Versuche mit Tillantin B, einem neuen Saatgutbeizmittel. [Ex-
periments with Tillantin B,a new seed disinfectant.|—Deutsche
landw. Presse, xlix, 97-98, pp. 600-601, 1922.

At the Laboratory of Plant Physiology attached to the dye-works
at Hochst-am-Main, a new fungicide, known as ‘tillantin B’, has
been produced for the control of bunt of wheat [T%lletia tritic:],
covered smut of barley [Ustilago hordei], and loose smut of oats
[U. avenae]. The mixture is stated to contain a new copper com-
pound and a very powerful arsenical substance, which, it is claimed,
produces an increased activity of the copper and absolutely counter-
acts any possible injury to germination.

Laboratory experiments showed that bunt spores could be
destroyed with 0-01 per cent. of tillantin in 10 minutes. In field
tests carried out at Hochst the yield in one series was increased by
the use of tillantin to the extent of 14 per cent. as compared with
the controls and with seed-disinfected with copper sulphate. In
another series there was an increase in the yield of 60 per cent.
over untreated seed and of 29 per cent. over seed treated with
copper sulphate. In all these experiments the sprinkling method
was adopted.

Another test carried out at the Giessen Agricultural Institute
confirmed the results obtained by the manufacturers. The yield
from seed immersed in tillantin exceeded that from the untreated
controls by 23 and 32 per cent. respectively in two separate series
of tests.

Mvuier (H. C.) & Mouz (E.). Neue Versuche zur Bekampfung
des Roggenstengelbrandes. |New experiments in the control |
of flag smut of Rye.]—Deutsche landw. Presse, xlix, 76, p. 491,
1922.

In the autumn of 192] disinfection experiments were carried out
with rye seed grain infested with flag smut (Uvocystis occulta).
The following preparations were used : rye fusariol, 23 gm, to 15 1.
water, uspulun 0-33 per cent., germisan 0-25 per cent., and kalimat
0-25 per cent. The seed was sprinkled in every case. On 15th April,
1922, the results of the different treatments were compared. The
growth in all the plots was very satisfactory. As regards disinfec-
tion, the best results were obtained with kalimat supplied by the
firm of Ludwig, Meyer at Mainz, the average percentage of smutted
plants being only 0-5. Uspulun and germisan reduced the infection
to an average of 2 and 2-5 per cent. respectively. Slightly less
satisfactory results were given by fusariol, the average percentage

et

of smutted plants being 5-5. In the untreated control plots the
average of infection was 66-5 per cent.

JANSON (A.). Bekampfung des echten und falschen Meltaus.
[Control of powdery and downy mildew.]— Deutsche Obstbau-
zett., Ixxviil, 23, pp. 224-225, 1922.

Owing to the scarcity of Sicilian dusting sulphur during the war
the writer made use of the precipitated ground sulphur known in
the trade as ‘Pri’. The results were sufficiently favourable to
justify further experiments on a larger scale, and these have been
undertaken since 1919. Roses (wild and cultivated), currants,
gooseberries, fruit trees, vines (outdoor and conservatory), cucumbers,
beans, maize, kohlrabi, cabbages, and chrysanthemums have all
been successfully treated. Even in large quantities, e.g. 100 kg.
per hect., precipitated sulphur is absolutely harmless to the plants.
The preparation is stated to be considerably cheaper and more
economical in use than other sulphur mixtures, and has the
additional advantage of being an excellent insecticide.

ERIKSSON (J.). Betningsférsék med uspulun och supersolfo sasom
kampmedel emot stinksot a vete. [Steeping experiments with
uspulun and supersulphur for the control of bunt of Wheat. ]—
Kungl. Landbruks-Akad. Handl. och Tidskr., 1xi, 7, pp. 607—
610, | fig., 1922.

The author describes experiments made in the autumn of 1921
in the control of bunt of wheat (Z%illetia ‘curies’) by uspulun and
supersulphur, the latter being a dark, thick, heavy liquid, consisting
mainly of calcium polysulphides, manufactured from the by-products
of illuminating gas by the San Paulo gasworks in Rome [see this
Review, i, p. 67}.

Pansar winter wheat heavily infected with bunt was used, the
grain being immersed in uspulun solution at a strength of 2-5 gm.,
or supersulphur at 10 c.c., per litre of water. Each of the treated
plots received 50 gm. seed and an equal amount untreated was sown
in a third plot as a control.

In the early summer of 1922 the two treated plots were higher
and more advanced than the control. the supersulphur plot being in
flower by 22nd June; that treated with uspulun was somewhat
less advanced and the control comparatively backward. The crop
was harvested on 19th August when it was found that there was
83-8 per cent. of bunt in the control, 22-6 in the supersulphur, and
only 0-5 in the uspulun plot. On the other hand, a much heavier
yield was obtained from the plot treated with supersulphur than
from that treated with uspulun.

It is suggested that higher concentrations of supersulphur might
give a better bunt control and also that a combination of the two
fungicides might unite the practically complete bunt control
of uspulun with the apparently stimulating effect of supersulphur.

TrUESDELL (W. H.). Plant pathology in Crimea.—Piytopath., xii,
11, pp. 533-535, 1922.

Plant disease control is quite backward in the Crimea; power

sprayers are unknown and the sprays used are, when obtainable,

172

Bordeaux mixture and Paris green. Lime-sulphur is only known
as a dormant insecticide, and self-boiled lime-sulphur as a spray
against gooseberry mildew. The orchards are much neglected, no
doubt because of the conditions resulting from a prolonged period
of war and revolution.

Apple canker [Nectria galligena], apple scab (Venturia in-
aequalis), and pear scab [V. pirzna] are serious. Sclerotinia cinerea
and S. fructigena are prevalent, but only the latter is supposed to
be responsible for injury to the woody parts of the trees, especially
sweet cherries, advancing from the fruit to twigs and then to the
main limbs and trunk. In the limestone country north of the
Crimean mountains chlorosis is common in the orchards, but inter-
esting results have been obtained by injecting into the trees a
mixture of FeSO,, K,SO,, and MgSO, through holes bored in the
trunk, the foliage above the point of injection becoming green while
that below remains yellow. Gyimnosporangium sabinae is frequent
on pears and Sphaerotheca pannosu was observed on peaches.

PEYRONEL (b.). Sulla normale presenza di micorize nel grano
e in altre piante coltivate e spontanee. |On the normal
presence of mycorrhiza in Wheat and other cultivated and
wild plants.]— Boll. mensile R. Staz. Pat. veg., iii, 4-6, pp. 43-
50, 1922.

‘The author signalizes the invariable presence in a large number
of wheat crops examined by him in various parts of Italy, of an
endotrophic mycorrhiza agreeing in its main features with the
mycorrhiza described by previous workers on many other plants.
So far as he knows, the occurrence of an endophytic fungus-root
association of this character has not previously been remarked on
wheat, which, in common with the other cereals, oats, rye, and
barley, is usually regarded as a purely autotrophic plant. In view
of the variable nature of the fungus-root association as a general
phenomenon he is, however, prepared to find that mycorrhiza may
be absent under other conditions than those observed by him in
Italy.

The fungus is characterized by its sparse development on the
surface of the root, in contrast with the free growth that takes
place in and between the cells of the cortex. In addition to the
branched, haustorium-like ‘arbuscules’ present in many of the
cells, large, acrogenous vesicles of varying shape are frequently
formed and remind one of the zoosporangia of the Phycomycetes.
In the epidermal cells and in the layer immediately under the
epidermis, the hyphae are often characteristically bent in spiral or
knee bends and may become divided by septa into short, barrel-
shaped articulations which may even unite into small, pseudo-
parenchymatous stromata. The mycelium is, however, usually
hyaline or pale yellow and sparingly septate. On the extra-
matrical mycelium the author observed the formation of large,
barrel-shaped, moniliform conidia, in simple or branched chains,
not separating into their component spores readily. Under suitable
conditions, also, he obtained the formation of sporangium-like
bodies in all respects analogous with the vesicles produced within

173

the roots, and the similarity of these organs to the zoosporangia of
the Oomycetes is emphasized though zoospores were not observed.

While in some wheat plants considerable portions of the root
system are invaded by the fungus, in others it is restricted to
a few rootlets. Some differences in the morphology of the endo-
phyte were observed in different localities, and it is suggested that
these may depend both on the race of wheat cultivated and
on the environmental conditions (soil, meteorological factors, and
the like).

The same fungus was also found associated with the roots of
oats, barley, rye, and maize, as well as in several weeds of cultivated
fields, eight of which are named.

During the course of his examination of the roots of various
plants for the presence of this endophyte, the author has frequently
encountered a Chytridiaceous fungus allied to Asterocystis radicis,
the well-known cause of ‘ brilure’ of flax in France and Belgium.
On wheat and. other plants (especially Cruciferae) this fungus is
frequently present together with the endophyte already described,
but always confined to the root hairs and epidermal cells. No
injury seems to result from its presence, and the author is inclined
to regard it as forming a special type of mycorrhiza though with
parasitic potentialities.

In a foot-note added while the paper was in the press it is stated
that the endophyte has been isolated and mycorrhiza successfully
synthesized in pure culture.

Fox (E.). La dartrose de la Pomme de terre. [Dartrose of the
Potato.|—Comptes Rendus Acad. Agric. France, viii, 32,
pp. 844-848, 1922.

During the period from July to September, 1922, the disease
known in France as ‘dartrose’, due to the fungus Vermicularia
varians, caused severe damage to the potato crops in the Depart-
ments of Charentes, Vendée, Vienne, Loire, Ain, Bas Rhin, Seine,
Seine-et-Oise, Loiret, Sadne-et-Loire, Rhone, and Lot-et-Garonne.
The symptoms, as reported by Crépin [see this Review, ii, p. 27]
and previous workers, are described. Ducomet and others have
attributed its outbreaks to excessive drought and heat, but these
factors were not sufficiently marked during the past summer to
account for the epidemic.

The varieties attacked were an imported Dutch variety, Richter’s
Imperator, Wohltmann, Fin-de-Siécle, Merveille d’ Amérique, Lesquin,
Saucisse, Czarine, and Institut de Beauvais. The disease is stated
to be more prevalent on early than on late maturing plants of the
same variety. The same seed sown in two different localities has
given in the one case a healthy and in the other a diseased crop.
This does not preclude the possibility that infection is introduced
with the tubers, as the influence of environment on the develop-
ment of the disease is manifestly very great.

Dartrose not only reduces the yield of the crop but also impairs
the quality. Control measures cannot be evolved until the source
of the disease and its conditions of development have been studied
in greater detail. Ducomet has shown that V. vurians can pass
from the seed tuber to the new shoots, and seed should therefore

174

not be procured from infected localities. All débris from infected
crops should be burnt, while the efficacy of the methods of seed
tuber disinfection employed against scab and Rhizoctonia deserve
testing.

Marre! (L.). La vaiolatura delle foglie dell’ ‘ Arachis hypogaea’
Linn. dovuta a Cercospora. [The spotting of leaves of
‘Aruchis hypogaea’ Linn, due to Cercospora].—Riv. Pat. Veg.,
xii, 1-2, pp. 7-11, 1922.

In this paper a leaf-spot disease of groundnut (Arachis hypogaea),
observed in the Bereguardo district in 1921, is described. The
leaves showed from 5 to 40, roundish or oval, dark chestnut brown
spots of uniform colour, without a lighter centre or concentric
markings. The spots bore, on both surfaces of the leaf, small dots
consisting of the fructifications of a fungus. These were composed
of numerous conidiophores in bundles, the individual conidiophores
being geniculate, continuous (rarely uniseptate), brown, with a
lighter apex, and 40 to 47 by 4 to 5y. The spores were borne on
slight projections and were clavate, yellowish green, tapering
above, at first continuous then with 8 to 12 septa, and 50 to 110
by 4 to 7 p. ;

The fungus is a Cercospora which is considered to differ from
C. personata (B. & C.) Ellis and C. arachidis Henn. in the larger
spots of characteristic appearance, in the amphigenous fructifications,
and in the spore characters. It comes near the latter species,
however, and the author names it C. arachidis var. macrospora,
a Latin diagnosis of the new variety being given.

For the control of the disease the author recommends burning
the aerial parts of affected plants.

DucometT (V.). Variétes de Pommes de terre et galle verru-
queuse. [Potato varieties and wart disease.]—Jowrn. Agric.
Prat., \xxxvi, 45, pp. 898-895, 1922.

After a brief discussion of the work of the potato testing stations
at Ormskirk (Lancashire), Freeland (Pennsylvania), and Rostock
(Mecklenburg), the writer states that, in view of the increasing
danger of the introduction of wart disease [Synchytriwm endobioti-
cum| into France, some twenty English varieties, reported to be
immune, have been under observation at the Grignon [S.-et-O.]
Experiment Station for periods ranging from one to two years.
Several of these varieties have been simultaneously cultivated in
other parts of France. While it is too early to make definite
statements as to the intrinsic value and adaptability of the English
varieties, a few preliminary observations may be of interest.

In the first rank, both as regards reported resistance and general
vigour, must be placed the medium-late variety Great Scot, while
Kerr’s Pink, Abundance, Rhoderick Dhu, Arran Victory, and Bishop
also possess excellent qualities. The last-named appears to be
somewhat susceptible to leaf roll, but is likely to prove a commercial
success. As regards resistance to late blight (Phytophthora [infes-
tans]), the varieties have been classified at Grignon in the following
descending order: Kerr’s Pink, Rhoderick Dhu, Arran Victory,
Great Scot, Abundance, and Bishop.

nna cc SS a Sr eel ee ee eee eee

175

None of the imported varieties fulfils all the French requirements,
either because they are not sufficiently early or productive, or are
somewhat inferior in quality. Absolute immunity from wart
disease, however, outweighs a number of defects, and moreover the
latter can, in all probability, be remedied by judicious crossing.

SCHLUMBERGER (O.). Pflanzenschutz und Kartoffelziichtung.
[Plant protection and Potato breeding. |—F%hlings landw.
Zeit., xxi, 9-10, pp. 183-191, 1922.

The author, believing that as the science of crop protection
advances increasing attention will be given to preventive measures
as opposed to the direct treatment of disease, discusses the means
of preserving the health and vigour of selected varieties of potatoes
as well as the methods made use of in potato breeding. New
varieties should be tested not only as regards their behaviour on
ditterent types of soil but also in order to gauge their resistance to
disease. The work of Quanjer, Murphy, and Cotton is regarded as
establishing that leaf roll is an infectious disease capable of direct
transmission as well as of being conveyed by insects, mosaic being
similar in these respects. Tests for resistance to these diseases
must be carried out by interplanting with already infected crops of
varieties such as Industry and Eigenheimer, which are Enown to be
particularly susceptible to mosaic. Trials for resistance to blight
(Phytophthora infestans) should be carried out preferably in mild
and damp localities by interplanting with susceptible early
varieties.

Resistance to wart disease [Synchytriwm endobioticwm] is specially
important, and as the disease persists in the soil and increases in
virulence from year to year, all new varieties should be subjected
to tests of several years’ duration before being put on the market.
The western provinces of Germany are principally affected by this
disease, and the resistant, yellow-fleshed varieties are in great
demand there.

Questions of soil constitution and manuring also require careful
consideration. In Stutzer’s examination of soils carrying crops
affected with leaf roll, 0-75 per cent. of free alkali was found. Soil
analyses made by the author in East Havelland showed that the
pronounced exhaustion of the potatoes in that district was connected
with an excess of humic acid. Hiltner and Lang have recentl
again pointed out that the capacity to utilize and benefit fully from
artificial fertilizers is contined to good varieties, poor varieties being
marked by their lack of response to fertilization.

The different means of maintaining the varieties in a healthy
condition require further study. According to the most recent
investigations their development depends not only on the constitu-
tion of the soil, but to an even greater extent on meteorological
factors. The proper temperature for the winter storage of potatoes
and the correct time for harvesting are two other important ques-
tions demanding fuller investigation. The harvesting of immature
tubers has been recommended both in Germany and England under
certain conditions, but this has also been opposed by many.

The breeding of resistant varieties of the potato is complicated
by its heterozygotic constitution. Every grower is familiar with

176

the number of types that may arise from a single seed-berry, and
the consequent difficulty of knowing what hereditary qualities are
present in the parents used for crossing. Thus most of the so-called
resistant varieties, at any rate in Germany, are accidental products,
and in many cases their immunity has proved to be only temporary.
It is, moreover, still quite uncertain whether the hereditary quality
conferring resistance in the potato is absolute or merely relative.
Certain varieties which are stated to be immune from particular
diseases in England have proved more or less susceptible in Germany.
Many attempts have been made to secure early varieties resistant
to Phytophthora infestans, chiefly by the selection of resistant
plants in infected crops, but these have generally been found to be
late-maturing individuals and thus the object has been defeated.

The correlation between resistance to disease and other valuable
characters in the potato is also very imperfectly understood, and it
is uncertain how far breeding for resistance may be combined with
breeding for productiveness. It is, in fact, generally believed that
the factors of high yield and immunity are mutually exclusive.
Another point of great scientific and practical importance is the
unusual longevity of certain varieties, e.g. Cimbal’s Wohltmann and
its relatives. Possibly such varieties may represent, not pure lines,
but a collection of different types, varying in their soil and climatic
requirements and mutually supplementing one another under
unfavourable conditions.

The various problems indicated in this paper have been deeply
investigated in the case of cereals, and the same time and care must
be spent on their solution in that of the potato.

FRANCHINI (G.). Nouvelles recherches sur les trypanosomes des
Euphorbes et leur culture. [New researches on the trypano-
somes of Euphorbiaceae and their culture.]|—Bul/. Soc. Path.
exot., XV, 5, pp. 299-303, 1 fig., 1922.

The protozoa found in the latex of Huphorlia nereifolia, E. caeru-
lescens, E. anticurum, EF. lavo, and an undetermined species, have
been further investigated. In the last-mentioned, bodies resembling
the small rings of the malarial parasite were found, and also Leish-
maniform bodies and small amoeba-like organisms. In EF. nereifolia
the trypanosomes varied in form and dimensions and amoeboid
types sometimes occurred.

Cultures obtained in Néller’s medium revealed transitional stages
between the amoebae and the trypanosomes. There is first a small,
homogeneous body with amoeboid movements. Later this increases
in volume, the protoplasm becomes more differentiated, nuclei can
be seen, and the amoeboid movements are more ample. A membrane,
which expands and contracts somewhat rapidly, appears round the
whole or part of the body. Still later the U shapes appear, the two
free extremities being sometimes united by a thin membrane. Both
in the cultures and in the latex of the plants the trypanosomes were
very variable in size, the larger ones being less frequent and less
mobile. Other amoeboid types were also seen and encysted forms
were sometimes present.

Similar observations were made on the latex of Haxcoecuria
emarginata, the development of the trypanosome in the host plant

177

appearing to follow the same course as that described above from
cultures. Circular and Leishmaniform shapes also occur in this
host.

FRANCHINI (G.). Sur une amibe des Figuiers de plein air de la
région parisienne et sa culture. [Notes on an amoeba of out-
door Fig trees in the environs of Paris, and its culture. |—Bul/.
Soc. Path. exot., xiv, 5, pp. 287-292, 3 figs., 1922.

The amoebae previously mentioned [see this Review, i, p. 450] as
occurring in the latex of outdoor fig trees (Ficus carica) near Paris
varied considerably in size and shape. Some were rounded and
12 to 20 » or even more in diameter, others oval, 22 by 12 or 18 by
13 »; smaller forms also occurred. In addition to these, very elon-
gated flagellates, 28 by 4-5 or 22 by 2 y, with flagella 6 to 8 y long,
were present.

Cultures of the amoebae were successfully made on Noller’s
medium, the red blood corpuscles of which were ingested by the
amoebae in the same way as is done by the pathogenic species of
the human intestine. The forms observed in the fig tree resemble in
some respects those found in exotic Urticaceae and in Asclepiadaceae
and Apocynaceae, in which transitional forms between the amoebae
and the trypanosomes have been seen, and the author thinks that
the flagellate forms mentioned above are a stage in the life-history
of the amoeba. Flagellate stages are known to occur in Vai-
kampfia and the Myxoamoebae.

FRANCHINI (G.). Sur une amibe de la laitue (Lactuca sativa).
[An amoeba of Lettuce (Lactuca sativa)|.—Bull. Soc. Path.
exot., XV, 9, pp. 784-787, 1 fig., 1922.

In July, 1922, the author examined near Bologna a large number
of lettuces, one of which contained numerous amoebae in the thick
and acid latex. The plant had a sickly appearance, which may,
however, have been partly due to the excessive heat. The amoebae
varied in shape and dimensions; the protoplasm was very fine,
vacuoles were rare, and the ecto- and endoplasm were not
differentiated.

Cultures were obtained on Noller’s medium, amoebae being
discernible on the fourth day. The organisms moved freely and
were very similar to those of the latex, though slightly smaller.

The new amoeba, to which the name A. lactucae is given, appears
to belong to the group already described as occurring in various
latex-bearing plants of the Apocynaceae and Urticaceae.

FRANCHINI (G.). Essais d’inoculation de différents protozoaires
dans le latex des Euphorbes. [Attempts to inoculate various
protozoa into the latex of Euphorbiaceae.|—Bull. Soc. Path.
exot., XV, 9, pp. 792-795, 2 figs., 1922.

In this paper the author describes attempts to infect various
species of Huphorbia with protozoa of known origin from insects
and man, carried out in Italy in the summer of 1922.

Vigorous plants of L. swuliana, EL. segetalis, EB. pilulifera, and L.
ipecacuanha were inoculated with cultures of the kala-azar organism
[Leishmania donovani| from India, and these and other species

178

with organisms from oriental sore [Z. tropica] from Sicily. £. geni-
culata, E. segetalis,and E. pilulifera were inoculated with Herpeto-
monas muscae domesticae; and EH. geniculata with spirochaetes
and with flagellates of the Cercomonas and Trichomonas types of
human origin. Finally, several species were inoculated with the
flagellate from cabbage bugs (Pentatoma) recently described by the
author [see this Rewevw, 1, p. 311].

All the inoculated plants with their controls were placed in a
greenhouse well protected against insects, and the latex examined
at intervals. One of the two plants of HL. geniculuta inoculated
with Herpetomonas muscae domesticae showed clear signs of infec-
tion after a time, while two plants of 4. ¢pecacwanha inoculated
with the organism of kala-azar also became diseased, one more
severely than the other. The infected plants turned yellow, the
leaves fell, growth was arrested, and the shoots withered. The
latex was pale, very fluid, and deficient in starch; fifteen to twenty
days after inoculation it contained Leishmaniform organisms, round
or oval, generally isolated, and sometimes in process of division.
The other inoculations failed, except in the case of H. segetalis
inoculated from oriental sore when very slight infection occurred.

SANDERSON (A. R.). Brown bast.—Bull. Rubber Growers’ Assoc.,
iv, 8, pp. 880-381, 1922.

The author points out that the time during which tapping has
been in progress is an important factor in the increase of the
number of cases of brown bast in Hevea rubber trees. This increase

is much more marked from the first to the sixth year of tapping, —

i.e. on the virgin bark and first renewal, than later, irrespective of
the particular system of tapping employed. Finely developed,
well-grown trees appear to be more susceptible, especially up to the
age of eight years, than poorer ones, and the evidence so far
available indicates that the incidence of brown bast is in direct
proportion to the severity and frequency of the tapping system,
but that as time goes on cases occur in trees that have been lightly
tapped from the start.

The following figures are of interest as showing the increase
in the percentage of brown bast with advancing age. In one ease,
eleven year old trees showed 20 per cent. of disease and thirteen
year old trees 36-45 per cent. Another field of trees over twelve
years old was twice examined for brown bast with a six months’
interval between. At the second inspection there was an increase
of 0.6 per cent. of new cases, the total percentage of disease being
38:75. On another estate, where treatment for brown bast has
been given for some years, the first census showed 12 to 24 per
cent. of disease. A second census taken eight months later showed
an average increase of 5 per cent. in the number of cases, while
at a third inspection after a four months’ interval there was
a further increase of 1 per cent. The growth and bark renewal on
the estate in question were very good. In another field of 200
acres the cases of brown bast in the third year of tapping numbered
1,592 as against 1,066 in the first year.

Generally speaking, the annual increase in the number of cases

179

of brown bast is at present relatively low, on account of the
prevailing tendency to adopt a less drastic system of tapping.

The reduction in the yield of dry rubber in trees affected by
brown bast is frequently disregarded, yet the loss may amount to
30 per cent. or more. In extreme cases no latex can be obtained
within the usual limits as regards height of cut. The total annual
loss in revenue may be very considerable and must increase yearly
unless precautions are taken to check the spread of the disease.

MANEVAL (W.E.). Germination of teliospores of rusts at Columbia,
Missouri.— Phytopath., xii. 10, pp. 471-488, 1922.

During the last five years observations have been made at various
dates between autumn and spring on the resting period required by
teleutospores of different rusts occurring at Columbia, Missouri.
The author reviews the literature concerning the effect of moisture,
temperature, chemicals, and maturity upon germination, and then
describes experiments in which he tested the germination of teleuto-
spores, previously collected and usually kept at room temperature,
by floating them in 10 to 15 cc. of distilled water in a covered
dish incubated at room temperature. The tests showed that
Phragmidium potentillae-canadensis, Puccinia asparagi, PB. heli-
anthi, P. menthae var. americana, P. ruelliae, P. andropogoni,
P. peridermiospora, P. sorghi {[P. maydis], P. sydowiana, and
P. windsoriae, all eu-type rusts, were capable of germination in or
before December. As the season advances there is a marked
increase in the percentage of spores that will germinate in a given
time. For instance, teleutospores of P. helianthi required 103 days
for a high percentage of germination in October, 11 days in
December, 7 days in January, 5 days in February, and less than
one day in April. Similar results were obtained with P. menthae,
P. peridermiospora, and P. windsoriae.

The time required for germination to begin decreases with the
approach of spring. Spores of P. helianthi tested on 10th October
1917 germinated slightly in 70 days, on 27th December 1921 in
6 days, on 27th February 1918 in 1 day, and in April 1917 and
1922 in 1 to 2 hours. P. periderimiospora, P. windsoriae, P.
meithae, and P. ruelliae behaved similarly.

Germination is favoured by prolonged floating on water and by
alternate wetting and drying, and after it has begun in a culture
it will generally continue for a considerable time. Teleutospores
of P. helianthi germinated feebly at 28° to 29° C. but the promycelia
were abnormal and practically no sporidia were formed. Spores of
P. windsoriae, P. peridermiospora, and P. helianthi would not
germinate at 32°C. but gave positive results when removed to
room temperature (about 20° C.). Spores of P. helianthi failed to
germinate after floating on water at 38° C. for 48 hours, but
withstood drying for five days at 38° C. and still germinated.
Temperatures above the maximum delayed, but did not inhibit,
germination.

As compared with germination in distilled water, the process was
retarded in solutions with higher H-ion concentrations (P,, 4-6 and
5-4) in the cases of P. asparagi, P. sorghi, P. ruelliae, and P.
menthae. On the other hand, P. helianthi germinated in solutions

180

with a wide range of H-ion concentration (Py 3-85 to 8-4), the
limits for good sporidia production, however, being narrower
(Py, 4-6 to 6-5).

BLUMER (S.). Beitrage zur Spezialisation der Erysiphe horridula
Lév. auf Boraginaceen. [Contribution to the specialization of
Erysiphe horridula Lév. on the Boraginaceae.|—Centralbl. fiir
Bakt. Ab. 2, lv, 21-24, pp. 480-506, 5 figs,, 1922.

The mildew on the Boraginaceae, included by Salmon in the
collective species Hrysiphe cuchorucearum DC., is regarded by the
author, on morphological and biological grounds, as a distinct species,
E. horridula Lév. Although its specialization is not sharply
defined, several biological races can be distinguished, each of which
has its primary and secondary hosts. The former show infection
regularly at the expiration of the incubation period (six to eight
days). Secondary hosts are not regularly infected, and several
weeks may elapse before the first symptoms appear. Infection in
the latter case appears to result from conditions either very suitable
for the fungus or unfavourable to the host.

The following ‘formae speciales’ are distinguished: symphyti,
pulmonariae, cerinthes minoris, asperuginis, cynoglossi, echii-
myosotidis, and anchusae. Cerinthe major is a host for all of
these that have been tested and is stated to serve probably as
a ‘bridging species’ to enable the Oidiwm on Symphytwm to pass
to Kchium vulgare, and from LHchium and Myosotis to pass to
Cerinthe alpina. Most of these forms have several secondary
hosts belonging to different genera.

E. horridula therefore differs from the forms of /. cichoracearwin
on the Compositae in its less sharply marked specialization, the
latter being usually confined to a single genus, often to a few species
within the genus. It differs morphologically in the frequency of
3-spored asci and in the germination of the spores. Morphologi-
cally three varieties or races of the oidial stage of Z. horridula can
be distinguished. In race @ the conidia average 30 to 35 in
length; this race includes the f. sp. symphyti, pulmonariae, and
cerinthes minoris. Race b has conidia 21 to 30 long and includes
the f. sp. asperuginis and cynoglossi. Race c has conidia 25 to
28 4 in length and includes the f. sp. echii-myosotidis and a form
of unknown affinities on Lithospermum. It appears evident that
the same host may be attacked by more than one morphologically
distinct race as well as by different biological formae speciales.

BLUMER (S.). Die Formen der Erysiphe cichoracearum DC.
[The forms of Erysiphe cichoracearum DC.|—Centralbl. fiir
Bakt. Ab. 2, vii, 1-8, pp. 45-60, 3 figs., 1922.

In the present paper the author continues his observations on the
specialization of various races within the collective species Hrysiphe
cichoracearum [see preceding abstract]. The results of his
experiments, a description of which is given, showed that the
mildews on the Compositae were somewhat highly specialized, all
attempts to communicate the infection to other genera than that
from which the material was taken being unsuccessful. The
author, however, does not regard these results as conclusive, the

181

experiments not having been conducted on a sufficient number of
plants of varying ages. Probably in many of the experiments
only the primary hosts were attacked. There is some evidence
that the resistance of plants to mildew decreases with age, the
disease generally being most virulent in the late summer and
autumn.

E. cichoracearum embraces a large number of biological races
of very unequal virulence. The forms occurring on Centawrea
montana and C. scabiosa are very probably confined to these hosts.
Within the genus Hieraciwm are two biological forms, one of which
is restricted to the sub-genus Pilosella and the other to the Huszer-
acia. The oidia on Senecio vulgaris, Centawrea jacea, C. phry-
gia, C. carniolica, and Cirsium eriophorum attack principally
species of one section within a genus. The strains on Arctium,
Sonchus, Prenanthes, Eupatorium, and Cirsium oleracewm attack
all species within the respective genera with approximately equal
virulence. Kobel has suggested [see this Revew, i, p. 79] that in
parasitic selection the chemical affinity of the proteins in the host
plants may be of paramount importance. The larger the genus the
greater is the probability of its chemical heterogeneity, which
would be reflected in parasitic selection within the genus. In the
present case the individual species of the large genera Centawrea,
Cirsium, and Senecio react to the Oidium exactly in the same way
as genera of the Boraginaceae [see preceding abstract]. The species
of Arctium, however, react to the Ocdiwm in the same way as the
Cucurbitaceae, specialization within the genus or family being
absent in both cases.

The average dimensions of the conidia of the various races of
E. cichoracearum referred to above, taken together, were 24-40 to
35°39 by 12-55 to 20-53. On Serratula rhaponticum and
océasionally on other hosts irregular as well as normal conidia
were found, the former being very reminiscent of Ovulariopsis
Pat. & Har. (Phyllactinia) or Oidiopsis Scalia [Leveillula tawrica
(Lév.) Arn.]. According to Arnaud (Les Astérinées, ii, 1921), these
irregularities would indicate reversions to primitive types.

Several of the biological races are distinguished from the others
by the size of the conidia (e.g. the form on Arctiwm has conidia
34 by 20) and these differences, though slight, indicate potential
morphological separation. The genera Hieracium and Centaurea
are each susceptible to attack by two morphologically and_biologi-
cally distinct types of Oidiuin. Neger’s experiments (flora, xc, 1902)
suggest that two distinct biological races also occur on Artemisia,
one on A. absinthium and the other on A. vulguris, and the
author’s preliminary examination has revealed possible morpho-
logical differences between these two forms.

Larrerty (H. A.) & PerHypripGe (G. H.). On a Phytophthora
parasitic on Apples which has both amphigynous and para-
gynous antheridia; and on allied species which show the
same phenomenon.—Scient. Proc. Royal Dublin Soc., xvii, N.S.,
4, pp. 29-43, 2 pls., 1922.

In the present paper the authors describe a rot occurring in apples
in Ireland. Cultural and inoculation experiments proved the causal

182

organism to be Phytophthora syringue and not P. cactorwm, the
species that has usually been found to cause rot in apples and pears
in other countries. Economically the disease does not appear to be
important, and it would probably be easily controlled by the
destruction of all infected fruits.

The decayed apples had dark brown skins, but they were more
or less firm and elastic to the touch. No superficial wounds were
found, nor could any external indications of fungous growth be
seen, though some of the lenticels showed smail white tufts of
hyphae after the affected fruit had been kept under a bell-jar in
the laboratory for a few days. This mycelium bore a. few
sporangia and in addition sexual organs, which were found in the
basal portions of the tufts and were of two types, the majority of
the antheridia being paragynous (i.e. lateral or near the base of the
oogonium, but not surrounding, or penetrated by, the latter), while
a few instances of amphigynous antheridia of the type first dis-
covered in P. erythroseptica (i.e. surrounding the oogonial stalk)
occurred. The flesh of the diseased apples was brown and permeated
by a rather coarse, non-septate mycelium, the hyphae being both in
and between the cells. The white aerial mycelium, which was
present in the cavities of the core, bore neither sporangia nor sexual
organs, but the latter were found embedded in the soft tissues
above and below these cavities. Here again antheridia of the
paragynous type predominated.

The occurrence of both types of antheridia on P. syringae was
confirmed by means of pure cultures obtained from portions of
single hyphae, from single sporangia, and from a single oospore.
In all cases the fungus produced sexual organs having both amphi-
and paragynous antheridia. Sporangia are not produced abundantly
as a rule, but when formed are borne on long, sympodially branched
hyphae. They are obpyriform when mature, with no apical papilla,
and average 40 by 27 uw. Germination is by zoospores, or sometimes
by a germ-tube which frequently bears secondary, tertiary, &c.,
sporangia after a short growth. The oogonia are borne on rather
short, lateral hyphae, and are pear-shaped and about 28, in
diameter on an average. The antheridia, when lateral, are small,
irregular, terminal swellings on short stalks which may arise either
from the oogonial stalk or a neighbouring hypha. Antheridia of
the amphigynous type resemble those already described in P.
erythroseptica. The oospores are usually hyaline, spherical, and
average about 25 yw in diameter, with walls from 1-5 to 2m thick.
The fungus was proved to be pathogenic to apples and pears, but
had no effect on potato tubers.

Cultural studies of P. cactorwm and P. fugi received from several
sources were also carried out. The authors give reasons for
regarding these two species as distinct both morphologically and in
their parasitic capabilities. In both cases sexual organs with amphi-
gynous antheridia were occasionally produced, though the pre-
dominant style was the paragynous. The occurrence of bodies
termed ‘sphaero-conidia ’, round, usually mtercalary spores, 33 to
40 » in diameter, and germinating by germ-tubes, is reported in
both species.

With the removal of these three species from the genus Vozenia,

183

founded by Pethybridge for the species of Phytophthora with para-
gynous antheridia, the species nicotvanue remains the only one in
which up to the present amphigynous antheridia have not been
observed. As further study may reveal their presence in this
species also, the authors propose to abandon the name Nozema and
reunite all species in the one genus Phytophthora.
Based on the mode of development of their sexual organs, the 22
species contained in the genus may now be grouped as follows:
A. Species in which, so far as is known at present, the anthe-
ridia when present are always amphigynous :

1. P. infestens (Mont.) de Bary. 7. P. terrestris Sherb.

2. P. phaseoli Thaxt. 8. P. allii Saw.

3. P. colocasiae Racib. 9. P. melongenae Saw.

4. P. arecae (Colem.) Pethybr. 10. P. meadii McRae.

5. P. erythroseptica Pethybr. ll. P.eryptogea Pethybr. & Latt.
6. P. parasitica Dastur.

B. Species in which the antheridia are preponderatingly para-
ous, but are sometimes amphigynous :
12. P. cactorum (L. & C.) Schroet.
13. P. fug: Hartig.
14. P. syringae Klebahbn.

C. Species in which, so far as is known at present, the anthe-

ridia are always paragynous:
15. P. nicotianae de Haan.

D. Species in which the mode of development of the sexual
organs is not fully known, or in which these organs
have not yet been found :—

16. P. thalictrt Wilson & Davis. 21. P. Jics Rau.

17. P. agaves Vill. (?). 22: P. citrt Rau.

18. P. fuberi Maubl. [ But see

following abstract. |

19. P. theobromae Colem. [A 23rd species, P. palmivoru

20. P. jatrophae Jens. Butl., overlooked by the
authors, should be added to
this group. |

Of these, P. thalictri is probably closely allied to P. phaseoli,

and may ultimately be found to belong to group A. P. agaves and

P. jatrophae have apparently so far not been described, and the

latter (which has been issued in culture form) may be identical

with P. nicotianae. On-P. fict and P. citri, which were provisionally

named in 1915, nothing further has been published. P. faberi and

P. theobromae are probably synonymous. The latter is said to be

closely allied to P. arecae, which would place it in group A, but

antheridia are either absent or rare, and it is not known whether they

are amphi- or paragynous. [The discovery of oospores with amphi-

gynous antheridia in P. fuberi is now reported. See next abstract. |

Asupy (S. F.). Oospores in cultures of Phytophthora faberi.—
Kew Bull. Mise. luform., 9, pp. 257-262, 1922.
Phytophthora fabert Maubl., the cause of pod rot, patch canker,
and chupon wilt of cacao in the West Indies and most other areas
where J'heobroma is cultivated, has so far never been observed to

184

form oospores either in nature or in pure cultures; the bodies seen
by Coleman and Rorer, and believed by them to be oospores, were
devoid of antheridia and are considered by the author to be pro-
bably nothing but chlamydospores. The behaviour of the fungus,
however, was found to be different when grown in mixed cultures
with more or less. related forms. Two of these were used. One
was a species of Phytophthora that attacks the coco-nut palm in
Jamaica (causing a serious bud rot) and has been identified as P.
palmivora, while the other was a Phytophthora isolated in 1922
from rotting cotton bolls in St. Vincent. Neither of these two forms
produces oospores in pure culture, and they appear to be identical
in their vigour of growth, mycelial characters, and asexual repro-
duction. The cacao fungus differs from them in growing less
vigorously and in developing sporangia less luxuriantly but, chlamy-
dospores more freely, as well as in not forming characteristic
mycelial aggregates that are usual in cultures of the coco-nut form.
In all other respects, including the conidiophores and shape and size
of the sporangia, P. fuberi cannot be distinguished in pure culture
from P. palmivora and the cotton boll fungus, but these last two
have not been found capable of infecting cacao pods.

The first observations on pure cultures were made by the author
at Kew during the summer of 1920. Pure and mixed cultures of
the cacao and coco-nut bud rot fungi, isolated in Jamaica. were
grown in tubes on slants of French bean agar in an incubator at
25°C. At the end of two months the pure cultures contained no
oospores, while in the mixed cultures, obtained by inoculating the
slants with the two organisms at a distance of about an inch from
one another so that the independent colonies of each form met and
mingled in a few days, oospores developed freely throughout the
colony of the cacao fungus, and as far as the centre of the other
growth. The mature sexual bodies were of the P. infestans type,
with persistent amphigynous antheridia and a_ golden-yellow,
thickened, oogonial wall. The mean size of the oospores was 23-3 pu
with a variation from 19 to 26-5 p.

With a view to controlling these results, pure and mixed cultures,
technical details of which are briefly described, were grown in 1922
in Barbados with the cacao, the coco-nut bud rot, and the cotton
boll forms. No oospores could be found in any of the pure cultures,
nor were they present in the mixed cultures of two isolations of the
coco-nut form or in mixtures of the latter with the cotton boll form,
but in all the mixed cultures containing the cacao Phytophthora
oospores were produced with the same characteristics as described
above. A persistent antheridium, usually hyaline but occasionally
yellow, was also present. The oogonia and antheridia always
appeared to be developed on separate hyphae, but it was not
possible to trace these hyphae definitely to the same mycelium.
There was mutual penetration of the two colonies, but the more
vigorous coco-nut and cotton boll strains appeared to push into the
colony of the cacao fungus deeper than the latter did into their
zones. The latter tendency was clearly shown in a number of
mixed cultures in which a colony of the coco-nut form was allowed
to develop for two days before the cacao fungus was inoculated on
the upper part of the slant. Im these examples oospores were

185

present up to the apex of the slant, and the mycelial aggregates of
the coco-nut strain were present at the apex also, indicating that it
had grown through the cacao colony.

The absence of oospores from pure cultures of the three Phyto-
phthoras, their close relationship as indicated by the mycelial growth
and the size and shape of the asexual spores, and the more vigorous
growth of the coco-nut and cotton boll strains which appear to be
identical, suggested that all may be strains of one heterothallic
species, the two more vigorous strains being plus strains and the
more weakly growing cacao form a minus strain. This view, how-
ever, is not supported by the fact that oospores of the same type
and the same mean size and variation were also formed in mixed
cultures of the cacao fungus with an unrelated species, namely,
P. parasitica, isolated from Ricinus communis in India, The
latter fungus is quite distinct from the other forms here mentioned
both in producing oospores freely in culture and in its morphological
and other characters.

The above observations show that the oospores formed in the
mixed cultures are actually those of P. faberi: they are substantially
larger than those of P. parasitica, but approach closely in size to
those of P. meadiz and P. colocasiae. The cotton boll Phytophthora
is apparently identical with P. palmivora. The absence of oospores
both in pure and mixed cultures of this species and some growth
differences, as well as its inability to infect cacao pods, distinguish
it from P. faberi, and the author regards it as no more justifiable to
include it in one species with the latter than to unite it with P.
meadir.

Howarp (N. O.). The control of sap-stain, mold, and incipient
decay in green wood with special reference to vehicle stock.
—U.S. Dept. of Agric. Bull. 1037, 55 pp., 2 pl., 25 figs., 1922.

Green timber containing a high percentage of sapwood often
suffers considerable damage during periods of transit and storage,
especially during the late spring and summer months, Sap-stain
may be divided into two classes, namely (1) the staining produced
by chemical reactions due to the agency of certain oxidizing enzymes
present in the wood itself; (2) fungous stains (blueing) caused by
species of Ceratostomel/la and other fungi [see this Review, ii, pp. 49,
50]. The degree of susceptibility to sap-stain varies considerably
in different species of timber. Among the conifers, southern and
western yellow pine [Pinus palustris and P. ponderosa|, sugar
pine [P. lambertiana], and the spruces appear to be readily stained,
while red gum [Liquidambar styraciflua], red oak | Quercus rubra],
white oak [Q. sii and hackberry [Cée/tis|, among the broad-leaved
trees, exhibit great susceptibility.

Superficial discoloration is caused by a number of moulds. Those
recorded, either by previous investigators, or isolated during the
work here reported, include 7 species of Graphiwm, 10 of Penicil-
lium, 4 of Aspergillus, Fusarium arthrosporioides, Alternaria
tenuis, Stachybotrys alter nans, Cephalothecium rosewm, Chaetomiuwm

sp., Stemonitis sp., Gliocladiwm sp., Hormodendron sp., Hormisciwm |

sp., Cladosporium sp., Citromyces sp., Clonostachys sp., Haplo-
graphium sp., Mucor sp., Oidiwm sp., Syncephalastrum sp., and

—

186

Trichoderma sp. Neither the blue-stain nor the mould fungi, how-
ever, cause any appreciable dissolution of the wood fibres, so that
the strength and durability of the timber are not materially affected.

The methods used in felling and handling the timber in the woods
and the subsequent handling during transit and storage are briefly
considered in relation to their influence on the development of
moulds. Kiln drying is stated to eliminate or reduce decay, sap-
stain, and moulds. Steaming the green timber is sometimes
practised, and experiments carried out at the Forest Products
Laboratory at Madison, Wisconsin, showed that it was effective at
atmospheric pressure, when applied for not less than three hours,
in killing surface fungi, but that the steamed timber moulded freely
subsequently, unless piled so as to secure an ample circulation of
the air.

Experiments in the chemical treatment of green wood showed
that creosote dipping of red oak spokes prevented sap-staining but
not the occurrence of moulds. The creosote bath was nearly as
effective at 80° to 90° F. as at 150° to 155° F. Mercuric chloride
(1 per cent.) was probably the best antiseptic for the control of sap-
stain and moulds. Somewhat less satisfactory results were obtained
from the use of 5 per cent. borax solution, and from dry quicklime,
while common salt was quite ineffectual.

A further series of experiments was undertaken to determine the
comparative values of various antiseptics and preservatives used
for dipping red oak blocks. Where possible the solutions were
made up to contain 1 per cent. by weight of the anhydrous salt.
The blocks were immersed for approximately 10 seconds in the
solution, drained, and then thoroughly sprayed with suspensions of
the spores in water. Fifteen of the moulds above mentioned were
employed. It was found that the blocks dipped in sodium car-
bonate, sodium bicarbonate, sodium fluoride, sodium bifluoride,
ammonium fluoride, magnesium silicofluoride, zinc silicofluoride, and
bleaching powder became severely moulded on exposure to a tem-
perature of 80°F. and a relative humidity of 85 to 100 per cent.
for three to four weeks. Potassium alum, potassium chlorate, and
copper sulphate seemed to incite the growth of most of the fungi
used in the inoculation experiments, especially Aspergillus niger.
Borax effectively controlled sap-stain and prevented all but a slight
development of mould. The efficacy of the preservatives was not
increased by the addition of hygroscopic substances such as sodium
chloride, calcium chloride, and glycerine. Of the organic compounds
and mixtures tested, creosote and kerosene gave the best results,
followed by mykantin, which, however, stained the wood yellow.

It is evident from these and the other investigations described
that the prevention of sap-stain, mould, and incipient decay in green
material can be best effected by a combination of remedial measures,
of which the following are especially important. Care in the selec-
tion of raw stock, which should be free from fungous infections ;
expedition in the movement of raw stock from the felling of the
logs to the stage in manufacture when the wood becomes sufficiently
_ dry to withstand the attacks of fungi; provision for ample ventila-
tion of the stock, thus ensuring at least surface drying; the kiln
drying of the stock whenever possible; and in special cases steam

187

treatment or the use of antiseptic dips, followed by proper piling
[full directions for which are given] to ensure adequate ventilation.

Scumitz (H.). Note concerning the decay of western Yellow Pine
slash caused by Polyporus volvatus Peck.—Phytopath., xii,
pp. 494-496, 1 fig., 1922.

This note reports briefly the frequent occurrence of Polyporus
volvatus, especially on western yellow pine [Pinus ponderosa | slash,
in the north-west of the United States. The fungus has not been
proved to be a parasite, though the possibility has been previously
suggested, and the observations recorded by the author indicate that
it has at least weakly parasitic tendencies.

STEVENS (Ff. L.). A fungus destructive to asphalt shingles.—
Phytopath., xii, 10, p. 497, 1 fig., 1922.

A roof of asphalt shingles, the shingles consisting of felt paper
(similar to that used under carpets), saturated with asphalt and
backed on one side with slate, was destroyed by a Basidiomycetous
fungus, the mycelium of which resembled Merulius lacrymans.
Stock shingles in storage are reported to be sometimes similarly
damaged. The hyphae were found to have penetrated the shingle,
subsisting presumably on the felt paper.

GARD (M.). Sur le dépérissement des jeunes noyers en 1922.
[On the dying-off of young walnut trees in 1922.|—Comptes
rendus Acad. des Sciences, clxxv, 17, pp. 716-718, 1922.

During the spring and summer of 1922 a large number of young
walnut trees in south-western and central France suffered from
a disease the chief symptom of which was a severe die-back of
twigs and branches, often reaching far down the trunk and in some
cases even killing the whole tree. This condition was sometimes
accompanied by various external lesions; the bark sometimes
peeled off and rolled up, and wounds formed at the forks of the
branches from which a blackish and foul-smelling liquid was
exuded. The bark turned black either completely or, in the large
branches and the trunk, partially, sometimes only on one side.
Many of the cells of the cortex, phloem, and cambium were
blackened, and the discoloration extended into the medullary rays
of the wood, though in the larger limbs it was limited to the newly-
formed layers. The vessels contained gum. No organism could
be found regularly present in the affected tissues and a physiological
explanation has been sought.

The author believes this disease to be the consequence of the
early autumn frosts of 1921, when the trees were still in full
vegetation. The fact that the less vigorously growing trees with less
sap were spared though standing in the immediate vicinity of the
severely affected, more robust, sappy individuals is considered to sup-
port this view. In many cases the injurious effects were not visible
in the following spring, the trees giving out new, vigorous shoots
which, however, died back during the summer. This sequence of
events was due, in the author’s opinion, to cell injuries which
resulted in the slow production of toxic substances and their
diffusion with the renewal of growth to the more distant parts of

188

the tree. The disease was apparently not confined to walnut trees,
various other plants such as figs, grape vines, and Laurus nobilis
showing more or less similar symptoms.

Buin (H.). Iba maladie dite ‘de l’encre’ des Chataigniers. [The
so-called ‘ink’ disease of chestnuts.|—La Natwre, 2534,
pp. 282-284, 1922.

The so-called ‘ink’ disease of chestnuts constitutes a serious
danger to French sylviculture, especially in the Departments of
Ardéche, Corréze, Corsica, Gers, Lot, and Lozére. It is estimated
that the disease has already destroyed more than 30,000 hect. of
chestnut plantations.

Trees suffering from this disease present certain well-marked
symptoms. The upper branches wither first, then those lower
down. The leaves lose their brilliant green and become glaucous ;
their development is arrested, and they fall in August. The fruit
does not ripen and adheres to the husk even after its fall. The
roots become soft, spongy, and brittle, and exhibit deep purple or
almost black areas, from which flows an astringent liquid with
a pronounced empyreumatic odour. The tannin contained in this
liquid combines with the iron in the soil to form a substance
resembling ink. The small roots are withered, and their cortex
becomes loosened: they are invaded by dark-coloured hyphae
which penetrate the cortex and reach the medullary rays. In cases
where the disease is of long standing, black patches appear on the
trunk and branches shortly before the death of the tree. These
patches form cankers from which exudes a liquid similar to that
observed on the roots. It turns black on exposure to the air and
stains the base of the tree.

Chestnut trees attacked by ink disease may languish for several
years or die in a few months. No soil is exempt from the disease,
which is, however, much more virulent in moist, closely packed,
and impermeable soils. Trees growing on the banks of streams
and in plains or valleys are usually attacked before those on slopes
or in the mountains. Grafted trees are more susceptible than non-
grafted, and certain varieties, amongst which are Green, Early
Black, Early Red, and Corrive are extremely liable to infection.
Generally speaking, coppiced trees are resistant.

Mention is made of Mangin’s investigations which have led him
to the conclusion that the disease is caused by a fungus, Mycelo-
phagus castaneae, which destroys the mycorrhiza as they appear
and induces a progressive necrosis of the roots. The latter are
thickened and entirely enveloped in a fungous growth which
arrests the development of the mycorrhiza and deprives the tree of
the benefits normally resulting from symbiosis.

Experiments in the treatment of the disease have shown that
watering the holes, before planting, with a 20 per cent. solution
of iron sulphate produces excellent results. The introduction of
resistant varieties is, however, the most promising method of
dealing with the situation; Castanea dentata and C. mollissima,
originating in Japan and China respectively, have been imported
for French plantations with satisfactory results. This practice,
however, has now been discontinued. or very greatly restricted

+ — PF

189

[see this Review,i, p. 280], owing to the danger of introducing
material infected by Endothia parasitica, the cause of a very
serious chestnut disease, which is prevalent in China and Japan
but is as yet unknown in Europe.

KaurrMan (C. H.) & Kerper (H. M.). A study of the white
heart-rot of Locust, caused by Trametes robiniophila.— A vier.
Journ. of Bot., ix, 9, pp. 493-508, 3 figs., 1922.

The white heart rot of the black locust tree, Robinia pseudo-
acacia, caused by the fungus Trametes robiniophila, is very common
in Southern Michigan, though it does far less damage than the
attacks of the locust borer or of Fomes rimosus. The prevalence
of the disease cannot be gauged by the number of sporophores
observed, since the fungus fruits sparsely and the sporophore
is soon disintegrated by the effects of the weather and by insect
parasites.

A detailed examination of a diseased tree, thirty-five years old,
was carried out. It had borne a large sporophore the previous
year and another was growing from a frost crack at the time of
cutting, while there were several old scars on the trunk marking
the positions of earlier fructifications. Borer attacks were numerous,
and the internal condition of the wood indicated that the tree
must soon have succumbed to storms, though it still bore green and
vigorous leaves.

The fungus had entered through borer holes in the large upper
branches and had started a rot which worked down to the
trunk. The numerous borer channels contained mycelium. The
apparently sound wood was sharply cut off from the rotten areas
by a very fine brownish-black zone, one-fourth to one-half a milli-
metre in width. Inside this line was an area of slightly rotted
wood, light fawn to brownish-white in colour, solid in texture, but
softer and lighter in weight than the sound wood. This area of
incipient decay could be cut easily without breaking. Nearer the
point of origin of the rot was an area of completely decayed wood
of the same colour as the last, but very dry and friable, so that
it could not be cut without breaking. This area was marked in
the last stages of decay by white streaks composed of delignified
wood fibres.

The effects of the fungus on the elements of the wood are des-
eribed in detail. In the black border zone the elements were infil-
trated by a brownish substance, the cells of the medullary rays and
wood parenchyma being most heavily impregnated. The wood
fibres were the least attected elements in this zone. No hyphae
were found, though the holes made previously by the hyphae
passing from cell to cell were plentiful. The dark colour is believed
to result from chemical changes in the dead cells, but the exact
origin of the brown substance was not determined. In the area of
incipient decay hyphae were again absent, though the perforations
that had been caused by them were larger and more numerous than
in the border zone, especially in the medullary rays and wood
parenchyma, The cell contents of these last two tissues had entirely
disappeared. All the other elements showed evidences of fungous
attack, the wood fibres being still the least affected. The badly-

190

decayed area in the centre of the rotten core was so brittle as to
be difficult of examination. The bore holes of the hyphae were of
still larger size, and the cell walls were in places riddled by them.
The tracheids aa vessels were merely a broken mass of fragments,
but the fibres and medullary ray cell walls retained some degr ee of
cohesion. In the final stages nothing was left in a recognizable
form but the wood fibres, which were eroded and colourless from
delignification.

In the apparently sound wood, immediately outside the dark
boundary line, living mycelium was found in abundance, composed
of hyaline, branched, septate hyphae, 1 to 1-5 » in diameter. The
hyphae passed from cell to cell both through the pits and through
the normal wall, and were most numerous in medullary rays and
wood parenchyma. The mycelium was abundant up to 7 em. from
the black line and no doubt extended much further, so that there
was practically no sound wood left in this tree in a radial direction
from the rotten core, and in a vertical direction for at least 2 ft.
from the uppermost limit of the visible rot.

Tests of the strength of the wood were made from the apparently
sound portions. In crushing tests the wood was found to stand
only one-half to three-quarters (according to distance from the
rotted parts) of the standard pressure per square inch which this
timber should bear. The importance of this ‘advance rot’ is
now receiving recognition in the case of other timbers, research
into the cause of the loss of life during the war from weak spots
in aeroplane timber having been specially directed to this matter.

The authors state that in the majority of the heart rots of trees
hyphae are rare in the rotted tissues except when they occur in
isolated nests or pockets. In the present case they appeared to be
entirely absent from the areas of visible rot, except in the borer
channels. How they disappear is not known and requires further
investigation.

Scort (C. E.). Disease of Chestnut trees new to California.—
Monthly Bull. Dept. Agric. California, xi, 10. pp. 740-741,
1922.

Eight year old chestnut trees in Grass Valley, California, have
recently been attacked by a species of Fusicoccwm somewhat
resembling Endothia parasitica, the cause of chestnut blight in the
eastern United States. The first symptom of the disease is a
wilting or drooping of the foliage caused by the girdling of the
branch or trunk by the fungus. The latter probably gains admission
to the bark only through wounds. As it progresses it kills the inner
bark while the tissues surrounding the dead area continue to
enlarge and become elevated, leading to the production of a canker.
The main advance occurs longitudinally on the infected branch,
but extension also proceeds round the latter, interfering with the
passage of food and killing the parts beyond the canker. The
latter is more or less depressed according to its age, and may
extend for several feet along the limb.

The minute spores developed in old cankers may be disseminated
by means of insects, birds, implements, &c., to wounds in the

191

bark, where the disease will be reproduced under favourable
conditions.

Diseased branches should be removed and burnt, and small
cankers can probably be eradicated by excising all the diseased
bark. All pruning or cutting wounds should be well disinfected,
preferably with the cyanide of mercury—bichloride of mercury
mixture.

The growing of chestnuts in California is still in a more or less
experimental stage, being intended to meet the deficiency caused
by the destruction of this tree by Hndothia parasitica in the
eastern United States. Hence it is highly important to guard
carefully against the introduction of diseases and pests and to
attempt to eradicate or control the present outbreak.

CABALLERO (A.). El Boixat, o enfermedad de los Ajos, en Baiolas.
[‘ Boixat’, or disease of Garlic, at Banolas.|—Bol. R. Soc. Esp.
de Hist. Nat., xxii, 4, pp. 210-212, 1922.

For the last twenty years a disease, known locally as ‘ Boixat’,
has caused considerable damage in garlic fields in the Bafiolas
(Gerona) district of north-eastern Spain. The intensity of its
attack in bad years threatens ruin to an otherwise profitable
and. important industry, the loss in 1914 amounting to 300,000
pesetas or 30 per cent. of the total value of the crop.

Various causes have been put forward at different times to
account for the trouble, one being bacterial infection associated
with colonies of Rhizoglyphus echinopus, another being the attack
of Tylenchus devastatrix, with R. echinopus and Anthomia ceparum
as secondary pests. Like Fragoso, the author found Perono-
spora schleident in association with Macrosporium parasiticum on
specimens from the district referred to, but in all cases he also
found numerous globose-depressed, very hard, greyish-black, dull,
rugose bodies, up to 1 mm. in diameter, on the bulbs. The appear-
ance suggested the attack of a fungus belonging to the Tuberculari-
aceae, but further examination showed that only sterile mycelium and
sclerotia were present and the parasite was identified by the author
as Sclerotium cepiwworum. It is regarded as the most destructive
of the garlic parasites in this district. S. cepivorum has been
united by Voglino with his Sphacelia allii, and by Sorauer with
Botrytis cana. Delacroix and Maublanc, however, obtained nothing
but an abundant formation of sclerotia in all their cultures, and this
has also been the author’s experience.

To check the disease it is recommended to burn all diseased
plants, to suspend cultivation in the most infected fields, and to
steep seed bulbs likely to carry infection in a solution of formalin
at a strength of 1 to 300.

The Plant Pests Control Ordinance, 1922. Seychelles, 21st Sep-
tember 1922.

This Ordinance gives the Governor in Executive Council powers
to control the importation of all plants into the Seychelles and to
order any treatment necessary on such plants as are permitted to be
imported. The Head of the Agricultural Department is authorized
to dispose of imported plants and their containers by destroying

192

them, or by other methods, subject to the approval of the Governor,
if he thinks necessary. The Governor may declare the existence
of a pest and may regulate, on the advice of the Head of the
Agricultural Department, the treatment to be adopted against
such a declared pest. In the same way the Governor may declare
an area to be infected, and the transport of plants to and from
areas thus declared to be infected can be prevented under similar
regulations. The carrying out of the regulations is entrusted to
inspectors. The Governor may prohibit the transport of any plant
from Island to Island in the Colony. The owner or occupier of
any land suspected to be infected may be called upon by the Head
of the Agricultural Department—subject to appeal to the Governor
in Executive Council—to carry out any treatment deemed neces-
sary, failing which a penalty is imposed and the treatment will be
carried out by the Head of the Agricultural Department at the
owner’s expense. Penalties for non-compliance with this Ordinance
are specified, and the prosecutions are entrusted to the Agricultural
Department. Former Ordinances and Government Notices dealing
with similar matters are repealed.

Plant Pest and Disease Ordinance, 1921 (No. 38 of 1921): Regu-
lations. Dar-es-Salaam, Tanganyika, 19th September 1922.

The salient features of the Tanganyika Plant Pest and Disease
(Coco-nut) Regulations, 1922, are as follows. The owner, lessee, or
person in charge of any dead coco-nut palm shall immediately cut
it down, burn the crown and any decayed parts, and bury the rest
of the stem. An inspector may, at his discretion, prescribe the
cultural measures or treatment to be adopted in the case of infection
by pest or disease, and is authorized to superintend the work of
destruction, if necessary, and to fix a time-limit for the execution of
the prescribed measures. All dead leaves from the crowns of coco-
nuts must be removed and burnt. No palm may be mutilated
except for the purposes of tapping for the extraction of ‘ tembo’.
Inspectors are authorized to see that each coco-nut tree is sur-
rounded by an area not less than 5 ft. in radius free from under-
bush, underwood, grass, and weeds, and that these are cut down
twice a year on all coco-nut plantations. The use of coco-nut
stems as fence posts, in bridge building, and in other construction
work (except for the interior of buildings) is prohibited. By order
published in the Gazette, the Governor may temporarily prohibit
the practice of tapping for ‘tembo’ in any specified area.

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

APPLIED MYCOLOGY

Vou. I MAY 1923

Soursac (L.). Etude de quelques maladies de la Laitue et des
moyens de les prévenir ou de les combattre. [A study of some
diseases affecting Lettuce plants and of means to prevent or
check them.]|—Reprinted from Congrés powr lavancement des
sciences, Montpellier, 1922, in Bull. Soc. Path. Vég. de France,
1x, 3, pp. 207-213, 1922.

In this paper three diseases of lettuce are discussed. A mild
form of collar rot of lettuce and chicory plants due to Sclerotinia
libertuana has been known in the Rousillon District (Eastern
Pyrenees) for 12 to 14 years, but, no doubt owing to the introduc-
tion of more intensive cultivation, the disease has recently spread
considerably, its development being further helped by the adoption of
the trench system of irrigation, which transports the sclerotia from
plot to plot. In the United States, where Poole has studied this disease
on celery [see this Review, ii, p. 102], seedlings under glass are
severely affected, but the loss in the field crop is insignificant. This
is not the case in the Eastern Pyrenees, where glass is generally
dispensed with, the sowings being made in the field, and the plants
resulting from the thinning-out process being used for transplant-
ing. Whilst in the United States the maximum intensity of the
disease occurs at about the period when the young plants are ripe
for transplanting, in France it reaches its height when the plants
are two or three months old, the original sowings and transplantings
being nearly equally affected. Light soils and wet years are
favourable to the development of collar rot, which is also helped
by the humid conditions and heavy nitrogenous fertilization con-
nected with intensive cultivation. In 1921 the sowings made in
September were severely attacked, those of November much less,
and those of the following months were practically immune.
Healthy lettuce transplanted to the immediate vicinity of infected
plants in March remained free from the disease. The varieties in
descending order of resistance are: cos lettuce of more or less
straight growth, winter lettuce (‘laitue d’hiver’) of more or

E

194

less spreading growth, curly chicory (‘chicorée frisée’) and
endive.

Attempts to germinate the sclerotia in various media have failed
so far, probably because a sufficient resting period has not elapsed
for their maturation. Measures for the control of the disease are
now being tested.

Malformation of lettuce heads (‘cabuchage’) is a fairly frequent
disease probably of physiological origin. The percentage of affected
plants may reach 60 to 70. They are recognized by their folded
and shrivelled leaves, which form loose and dwarfed heads.

Finally a second malformation, characterized by multiple branch-
ing, of cos lettuce plants of the variety ‘romaine’, is deseribed.
This condition prevents the formation of heads and renders the
product unsaleable. The remedy for both these last-named diseases
appears to be a rigorous selection of seed.

WINGARD (S. A.). Yeast-spot of Lima Beans.—Phytopath., xii,
11, pp. 525-532, 4 figs., 1922.

A new disease of Lima bean seed (Phaseolus lunatus) was
observed in October, 1921, in Virginia and has since been found
to be rather prevalent and widely distributed in the State, as
much as 60 per cent. of the crop being attacked in some cases.

The disease only occurs on the seed in the pod, causing numerous
dark, sunken areas on the cotyledons; pods that appear to be
quite healthy may contain badly affected seed. When the latter is
attacked early it may die before ripening or remain undersized.
The testa is usually unbroken, the infected spot being dark brown,
somewhat sunken, and wrinkled, but sometimes it is ruptured, and
crater-like lesions are then produced on the cotyledons. In these
lesions, which are greyish-brown and granular, great masses of
ascospores of a yeast and a small number of vegetative cells and
young asci are found. The organism was readily isolated from
several lots of beans, the platings invariably yielding pure cultures.
It belongs to the genus Nemuatospora described by Peglion in 1901
(Centralbl. fiir Bakt., Ab. 2, vu, p. 754). It differs in certain
characters from the two species already described, and the author
names it V. phaseoli, a full description being given.

The cells vary widely in form, from the elliptical and spherical
types common in young cultures to mycelium-like strands, which
bud at the cross walls; curiously shaped cells, like miniature tennis
rackets, walking sticks, &c., are not uncommon after twenty-four
hours growth. In size the elliptical cells measure 8 to 14 by 6 to
10 yw, the mature spherical cells 20 p, and the mycelial strands 90
to 140 by 2-5 to 3-5 uw. Ascospores are produced in great numbers
on bean seed and in favourable nutrient media. The asci are
cylindrical with rounded ends, 60 to 85 by 10 to 12 yw; the asco-
spores, arranged in two groups of four, are 40 to 46 by 2-5 to3 yp,
slender, l-septate, slightly mdged at the septum, with an acute
apex, and a base extended into a slender, non-motile whip which is
about one-and-a-quarter times as long as the spores. The asco-
spores germinate by the basal cell swelling to a sphere about 6 » in
diameter, from which either a mycelial strand is produced or

ae

195

spherical cells are budded off. All the stages of the organism stain
readily with ordinary stains, and it is Gram positive.

It grows well on media suitable for yeasts, and the cultural
characters on six media are described. On beer wort agar the
colony is convex, circular, with entire margin and smooth surface,
opaque, dull, cream-coloured at first, then gradually turning to
brown. Asci are produced in forty-eight to seventy-two hours, and
after about three weeks the colony becomes surrounded by a
mycelial growth on which a second crop of asci is borne. The
optimum temperature in culture and for infection of Lima beans
is probably about 30° C.

The pathogenicity of the organism has been demonstrated re-
peatedly in the greenhouse. Negative results were obtained when
the pods were sprayed with a water suspension of the organism or
smeared with a pure culture, but the seed was readily infected
when the pods were inoculated through punctures. The symptoms
become evident within two or three days of inoculation, and are
quite conspicuous within seven to ten days. The organism was
not pathogenic on garden peas and only weakly parasitic on
tomatoes,

JONEs (S.G.). A bacterial disease of Turnip (Brassica napus).—
Journ. Agric. Science, xii, 3, pp. 292-305, 1 pl., 1922.

A disease of the white turnip has of recent years made its
appearance in North Wales, especially on land treated with lime
or a heavy dressing of nitrogenous fertilizers.

From a casual glance attected plants looked perfectly healthy,
but on closer examination it was seen that the very young leaves at
the centre of the crown had been destroyed, forming a tiny wound
which the fully expanded leaves effectively concealed. so that the
extent of the damage was often only revealed at lifting. In section
a diseased root showed a flask-shaped, soft, putrid core, surrounded
by a brown zone of healthy tissue. Sometimes the apical bud had
been destroyed, and three to five vigorous secondary crowns
developed in its place. r it

The causal organism was isolated by plating out in the usual
way. Fresh isolations attacked turnip blocks very rapidly, but old
cultures carried over for about twenty generations were found to
have lost their pathogenicity.

Infections were attempted by immersing for an hour uninjured
leaves (attached to the plant) in water containing the organism in
suspension. No infection resulted, and the author is of the opinion
that infection is preceded by mechanical injury (e.g. leaf cutting
insects or slugs). The earliest signs of disease appeared in the
young leaves, but attempts to infect them by inoculations gave
negative results. When the tender foliage at the growing point
was pinched off and the wound inoculated, infection always resulted
and typical symptoms were produced, except that when the roots
were of a dry, spongy texture, the diseased core was of uniform
brown colour instead of whitish-grey, the difference in colour being
due to oxidation.

Microscopical examination of affected tissues showed the cells to
be comparatively isolated, the cell walls, however, remaining intact.

196

The disintegration of the tissues appeared to be occasioned by the
solution of the middle lamella.

The separation of the by-products from the bacteria was attempted,
and by adding chloroform to the liquid of a vigorous culture filtered
through filter paper, a product was obtained which disintegrated
thin slices of turnip but which was sterile.

The causal organism, which has one polar flagellum, is fully
described. It has many characters in common with Pseudomonas
campestris BE. F. Smith and with Bacillus oleracea Harrison, but is
clearly most nearly related to Pseudomonas destructans Potter,
from which it difters chiefly by its mode of attack, by being Gram
positive, by losing its virulence on repeated culturing, and by pro-
ducing ammonia on some media. The author is of opinion that
it is a varietal form of the latter.

Meter (F. C.) & Link (G. K. K.). Bacterial spot of Cucumbers.—
U.S. Dept. Agric. Circ. 2384, 5 pp.,.1 pl., 1922.

This paper gives a short and popular description of two affections
of cucumber, the bacterial spot of fruit and angular leaf spot, both
of which occur frequently in the United States and also in Canada
and Europe, and are due to the same cause, Bacterium lacrymans.

The disease first appears on the cucumber plant in the form of
water soaked, translucent, round to irregular spots on the cotyledons.
The later leaves show similar but angular spots which extend along
the vein and which, under moist conditions, increase in number so
as to cover the entire leaf, a white, gummy exudate swarming with
bacteria frequently accompanying the spot. Within about eight
days the spots become dry and white or tawny; subsequently the
affected tissues may be knocked out, giving the foliage a ragged
appearance. The stems and petioles are occasionally attacked,
becoming water soaked and covered with a bacterial exudate. On
the fruit, which may be affected in the field or become contaminated
during the picking and packing processes, the spots first appear as
minute, circular, water soaked areas, which later become conspicuous
owing to the centres taking on a chalky white colour due to the
drying and cracking of the affected tissues. The spots remain
shallow, but they afford entrance to organisms which are capable
of producing secondary rots, and heavy losses occur in transit from
this cause. The disease may cause a stunting of growth, and the
reduction in leaf surface often leads to a lowering of the yield.

Hot, dry weather tends to check the disease, but rains, especially
if accompanied by wind, increase its spread.

The bacteria appear to be carried on the seed, and immersing the
latter in mercuric chloride, 1 in 1,000, for five minutes, then washing
thoroughly in water, gives a good control. Angular leaf spot can
also be controlled by spraying with a 4-450 Bordeaux mixture,
although the seed treatment is simpler and less expensive.

Hiccrxs (B. B.). The bacterial spot of Pepper.—Phytopath., xii,
11, pp. 501-516, 2 pl., 5 figs., 1922.

A bacterial disease of chilli pepper (Capsicwm annwwm) has been

very destructive in Georgia since 1920. On the leaves the spots

first appear as small, circular, pale-green pimples, somewhat raised

N97

on the under surface, and usually with a slight depression on the
upper. On old leaves, infection appears as dark green, water soaked
spots. Usually the centre of the spot collapses in a few days, while
the edges extend forming a circular or oblong, pale yellow or straw-
coloured patch, 1 to 10 mm. across with a border of water soaked
tissue which finally turns dark brown. Infected leaves fall, often
becoming yellowish before doing so.

On the stem, the disease forms inconspicuous, raised cankers, and
on the fruits more noticeable spots, which are pale green at first,
but soon turn brown and become cracked and wart-like.

Isolations from infected spots yielded a yellow bacterium, the
morphological, cultural, and physiological characters of which are
fully described. It is a short rod, usually occurring singly or in
pairs, rarely in chains. It is not very motile, but sometimes has
a single polar flagellum. Capsules are present on certain media.
It stains readily, but is Gram negative; grows moderately rapidly,
is a strict aerobe, and liquefies gelatine. On beef extract agar with
3 per cent. dextrose or saccharose, the medium became first alkaline,
then neutral, and finally acid, but with lactose it remained alkaline.
The group number for this organism should be B. 211. 2222523.

Hundreds of plants have been successfully inoculated with this
bacterium, and the latter re-isolated from them. The incubation
period in summer is about 10 to 15 days. The exact mode of pene-
tration of the leaf was not observed, but in early stages of infection
slimy masses of bacteria were found in the stomatal cavities and
adjoining intercellular spaces. The cells in contact with the mass
swell and break the epidermis, the bacteria spreading in the inter-
cellular spaces, forcing the cells apart, and finally killing them.

The identity of the organism is still uncertain. It resembles
those isolated from tomatoes by Miss Doidge in South Africa and
by Gardner and Hendrick in Indiana, but a comparative study of
the three organisms is necessary.

The bacteria appear to be carried on the seed. Mereuric chloride
(1 in 1,000) was quite effective in controlling the disease, but was
liable to do severe damage to the seed, whilst spraying four times
in the field with Bordeaux mixture reduced the infection consider-
ably but did not give complete control.

MonTEMARTINI (L.). L’applicazione degli Articoli 6 e 7 della Con-
venzione internazionale di Roma 4 marzo 1914 contro le
malattie delle piante. [The application of Articles 6 and 7 of
the International Convention of Rome of 4th March 1914
against the diseases of plants. ]—Riv. Pat.Veq., xii, 1-2, pp. 1-7,
1922.

In this paper the author enumerates the difficulties connected
with the practical application of Articles 6 and 7 of the International
oo for the Prevention of Plant Diseases signed at Rome in

914.

Article 6 gives each signatory State the right to restrict the entry
of plants covered by the Convention to certain selected places, and
Article 7 provides for the inspection of the imported material and
specifies the sanctions to be applied in case of disease being found,
contrary to the certificate accompanying the consignment. In such

198

a case the consignment is either returned or destroyed by fire at the
exporter’s expense, and the latter’s Government is immediately
advised of the steps taken.

From experience gained at the Milan office, the author questions
the practical utility of these measures, chiefly owing to the extreme
difficulty of satisfactory inspection. It is contended that it is
impossible to examine the material as minutely as the nature of the
case demands, and that the healthy state of part of a consignment
does not warrant the conclusion that the remainder is fit to pass
the frontier. There is also the packing to be considered; this is
very complicated in some cases, such as orchids, and requires
technical skill in handling which is not available at the Customs.
In the case of bulbs packed in boxes the difficulties are even greater,
as in practice it is impossible to examine them one by one. Some
parasites are hidden in the plant tissues and do not reach their full
development on the surface until the last stages of the growth of
the host. Others, such as Septoria [apii] on celery and Phoma
| betae] and Cercospor | bet icola | on beet, are seed-borne and invisible ;
others, again, are disseminated by the wind and inspection is power-
less to prevent them from invading a country. The disinfection of
all material sent would not be practicable for technical reasons.

The author concludes that the only effective remedy is increased
vigilance on the part of each individual State within its own borders,
which alone can make possible the prompt detection and eradication
of plant diseases; and this must be supported by strengthening the
frontier organization designed to prevent the entry of undesirable
material. :

Nevertheless, he thinks that the Articles under discussion should
be retained for cases in which the examination of one sample makes
a deduction as to the state of the remainder reasonably certain.

Brers (P. M.). Le Polyporus (Ungulina) inzengae de Not., parasite
du Peuplier. [Polyporus (Ungulina) inzengae de Not.,
parasitic on the Poplar.|— Bull. Soc. Path. Vég. de France,
ix, 3, pp. 166-168, 1922.

At Pare St. Maur (Seine), France, a black poplar tree (Populus
nigra) was observed to undergo a gradual process of decay, lasting for
several years, and finally to die. The stem was covered with the fructi-
fications of Polyporus (Ungulina) inzengae | Fomes fomentarius].
Several subsequent observations on other poplars bearing the same
fungus support the view that this species acts as a true parasite,
entrance being probably gained, in the cases seen, through wounds
caused by clumsy pruning. Its development on the poplar is slow,
and external evidence of its presence is only visible in the last
stages of the disease.

FERDINANDSEN (C.). Det plantepatologiske Arbejde i Danmark.
Phytopathological work in Denmark.|—Reprinted from Nor-
disk Jordbruksforskning, pp. 333-351, 1922.

The author gives an interesting account of the origin and develop-
ment of work on the diseases of plants in Denmark. The head-
quarters of the Danish Plant Protection Service, a branch of the
State Agricultural Experiment Board, are situated at Lyngby, ten

199

miles north of Copenhagen. The work is under the general super-
vision of the Director, and is organized in three separate divisions,
engaged respectively in botanical research, including fungous,
bacterial, and physiological diseases ; zoological research ; and exten-
sion work for the distribution in popular form of the results of
investigations. By co-operation with various experiment stations
and agricultural organizations, arrangements are also made to
conduct experiments and collect useful data in all parts of the
country. These data are used in the compilation of the ‘ Monthly
Survey of Diseases of Agricultural and Horticultural Crops’, which
appears from April to November.

The work of the extension or information section comprises the
issue of popular leaflets on the more general and familiar diseases,
replying to simple queries, procuring phytopathological material
for exhibitions, lecturing, journalistic work, and the arrangement of
summer meetings, excursions, and so forth.

During the last few years the standard of seed purity has been
greatly improved by the State Seed Testing Station, an institution
which works in co-operation with the Plant Protection Service.

In 1903, after Rostrup had shown that the annual loss to Danish
agriculture from black rust [Puccinia graminis] amounted to
Kr. 10,000,000 [about £400,000 at present], the law of 1869 pro-
viding for the extermination of the barberry was put into effect.
The second plant disease law, which was promulgated in 1921, is
concerned with the export and import of potatoes and has been
already noticed in this Review [i, p. 125].

Krankheiten und Beschadigungen der Kulturpflanzen im Jahre
1920. [Diseases and pests of cultivated plants in the year
1920.|—Mitt. biol. Reichsanst. Land- wnd Forstwirtsch., 23,
110 pp., 1922.

In the introductory section of this report Dr. Schwartz states
that the annual reports of the diseases and pests of cultivated
plants, formerly included in the agricultural reports published by
the Ministry of the Interior, will in future be brought out in an
abbreviated form by the Biological Institute at Dahlem. The
publication of the reports was interrupted by the war, and it was
found impossible to include the period 1913 to 1919 in subsequent
issues. The reports will be devoted mainly to the enumeration of
diseases and pests occurring in Germany during the year, with
special reference to their economic importance.

In the present report an attempt has been made for the first time
to prepare cartographic surveys of the distribution and varying
intensity of some of the more important pests and diseases. Such
surveys are intended to afford a basis for the systematic investiga-
tion of the correlation between the incidence of any given pest or
disease and the climatic and geological conditions of the district in
which it occurs. The material thus collected will in its turn serve
as a foundation for the scientific researches to be conducted at the
newly-established Laboratory.of Meteorology and Phenology in the
Biological Institute. During the period under review this laboratory
was engaged ‘mainly in preliminary work connected with the
organization of the National Phenological Service, but in future

200

the climatic conditions of the year and their influence on plant
cultivation will be discussed in greater detail.

The abnormal drought which prevailed during the summer of
-1920 was responsible for the very poor keeping quality of the
potatoes, while in some places the storage of damp tubers owing to
the rainy weather at harvest time caused decay. In the province
of Oldenburg the very heavy frosts which occurred in October 1919
completely interrupted the sowing of autumn seed, with the conse-
quence that germination was greatly retarded. A further sequel
to this delay was a very severe attack of stripe disease [ Helmintho-
sporium gramineum] on barley sown just before the frost, 60 per
cent. of the crop often being infected, while Lochow’s Petkus winter
rye suffered to such a degree from the snow fungus [| Fusariwm
nivale| that only one-third of the stand was left by the spring.

In the special section dealing with the fungous and physiological
diseases of economic crops, for which Dr. H. Pape is responsible,
only those diseases are referred to which were unusually destructive,
or of rare occurrence, or which presented special points of scientific
interest. Amongst the numerous records the following may be
mentioned :

CEREALS. Almost all the plant protection head-quarters reported
losses from bunt of wheat (V7/letia tritici), which was particularly
severe in Saxony. Loose smut of oats (Ustilago avenae) was also
very prevalent, the attack in Pomerania being the worst ever
experienced. The stripe and spot diseases of barley (Helmintho-
sporium gramineum and H. teres) appear to be on the increase
from year to year. The losses reported frequently amounted to
20 or 30 per cent. and even exceeded 60 per cent. of the crops in
some cases. Numerous reports of damage from cereal foot rots
(Leptosphaeria herpotrichoides, Ophiobolus herpotrichus, and Fusa-
rium spp.) were also received.

In Westphalia the rye crops on sand and sandy loam suffered
from an excessive concentration of acid in the soil as a result of the
dry weather in March. Oats were also affected, and in the manu-
facturing districts the phenomenon was wrongly attributed to
sulphuric acid injury. The plant protection experts consider that
the withdrawal of lime from the soil in these cases was correlated
with altered biological conditions due to lack of water.

Porarors. Blackleg [Bacillus atrosepticus] was reported from
nearly all parts of the country, while bacterial soft rot of the tubers
was particularly prevalent im Hesse-Nassau and Bavaria. Late
blight (Phytophthora infestans) was severe and widely distributed.
Wart disease (Chrysoph/yctis endobiotica) |[Synchytrium endobioti-
cum] gained a foothold in several new districts during the year,
and was reported from the following localities: Rhine Provinces,
Westphalia, Hanover, Schleswig-Holstein, Hamburg, Liibeck,
Mecklenburg, Brandenburg, Silesia, Saxe-Weimar, Eisenach, Saxe-
Meinigen, and Saxe-Gotha. Leaf roll was widely distributed, while
‘Krauselkrankheit’ was reported only from Liibeck and Oldenburg
and mosaic disease from Munster [Westphalia].

Roots. Tip rot (Bacillus bussei and B.lacerans) occurred severely
in Pomerania, especially on swedes. Root rot of beets (Pythiwm de
Baryanum, Phoma betae, and Aphanomyces laevis) was prevalent

ae

201

in many districts and completely destroyed certain fields in Olden-
burg.

eee Cucumbers (outdoor and hothouse) were severely
attacked by a bacteriosis [cause not specified] at Marienburg (West
Prussia), and by downy mildew (Pseudoperoinospora cubensis) in
Wurtemberg. Gummosis (Cladosporium cucumerinum) was twice
observed in the latter area, where blotch (Coryiespora melonis) also
occurred. Tomatoes in Wurtemberg were attacked by mildew
(Oidiwm lycopersici) and a leaf spot caused by Alternaria solani,
while near Hamburg Ascochyta lycopersici [Didymella lycopersici]
assumed the character of an epidemic. Sclerotinia libertiana and
Septoria lycopersici were each reported on this crop from two
different localities. Peas in Oldenburg sustained heavy damage
from wilt or St. Johannis disease (Musarium vasinfectum). Mars-
sonia panattoniana caused considerable losses in a salad garden in
Saxony.

Fruit. Cherries were reported to be attacked by bacterial blight
(Bacillus spongiosus) in only a single locality, but scab (Fusicladiwm
cerasi) and brown rot (Monilia) were unusually prevalent. Apple
mildew (Podosphuera leucotricha) was also exceptionally virulent
and caused heavy damage. In Berlin this disease was observed as
early as the end of March. Peronospora rubi caused some injury
to raspberries in Oldenburg, the variety ‘Superlative’ being chiefly
affected; while the raspberry cane blight, which may be caused
either by Didymella applanata [see this Review, ii. p, 128] or by
Comothyriwm fuckelii, was severe in Anhalt and Saxony.

American gooseberry mildew (Sphaerotheca mors-uvae) is steadily
extending in Germany, and there is now scarcely a district free
from it. In certain areas the harvest is stated to be decreasing
year by year as a result of its attacks. Polyporus ribis was
observed on gooseberries and currants in two localities.

Downy mildew of the vine (Plasmopara viticola) was severe all
over the vine-growing districts. In Wurtemberg the attack approxi-
mated to the catastrophic epidemic of 1906. Powdery mildew
(Oidiwm tuckeri) was also severe, while in Baden the ‘ rotbrenner ’
fungus (Pseudopeziza tracheiphila) caused a certain amount of
damage. :

Amongst the numerous other records of plant diseases, mention
may be made of an outbreak of Rhizoctonia violacea on young
pines, which destroyed some 4,000 plants in a nursery in Silesia;
and of a die-back of the branches of elms, attributed by v. Tubeuf
to over-blossoming, but which is of interest in view of the epidemic
disease of the tree in Holland recently recorded [see this Review,
li, p. 92].

JORSTAD (1.). Beretning om plantesykdommer i land- og have-
bruket 1920-21. I. Landbruksvekster og gronnsaker. | Report
of agricultural and horticultural plant diseases during 1920-21.
I. Cereal crops and vegetables.|—Reprinted from the Report
of the Minister of Agriculture, 79 pp., 24 figs., 1922.
This report contains a survey of the principal diseases of cereal
and vegetable crops observed in Norway during the years 1920 and
1921.

E 2

202

Besides notes on the common rusts, smuts, &ce., of cereals. there is
a full discussion on seed treatment. It is recommended that the
seed of oats and barley should be treated with formalin in preference
to copper sulphate, except in the case of stripe disease of barley
(Helminthosporium gramineum) when copper sulphate should be
used. Wheat and rye should be treated with copper sulphate instead
of formalin if the seed cannot be sown immediately after disinfec-
tion. On the whole, copper sulphate appears to injure germination
more than formalin, especially when the seed has been damaged in
threshing. Mercurial fungicides have been extensively used during
the last few years. They include 0-1 per cent. corrosive sublimate,
uspulun, sublimoform (1:400 formalin + 0.1 per cent. corrosive
sublimate), and fusariol (corrosive sublimate + copper sulphate).
These preparations are highly toxic and are not injurious to germina-
tion. They are primarily intended for the control of Fusarium
and stripe disease of barley, but are useful also in the suppression
of smut.

Fusarium diseases of cereals are of considerable importance in
Norway. The chief are the straw fusariose caused by F’. culmorwim
and the snow mould caused by Calonectria graminicola in its
conidial stage Fusarium minimum [F. nivale}.

Bright speck disease of oats [see this Review, i, p. 421], due to an
excess of alkali in the soil, can be successfully controlled by the
application of manganese sulphate at the rate of 50 kg. per hect.
A similar but much less serious disease has been observed on wheat
and barley. In the latter case the spots are very small, arranged
close together in rows, and dark brown in colour. This is pre-
sumably the disease formerly known as ‘spot necrosis’.

Another apparently physiological disease of barley is known as
the ‘finger-print disease’. Brown spots appear at the end of June
on leaves which are already yellowing, possibly as the result of an
insect attack. The exact origin of the spots has not been ascer-
tained, but they are in all probability non-parasitic.

Of interest are the records of Typhula trifolizt on red clover (the
first for thirteen years) and Ascochyta pisi causing a leaf spot of
lucerne. Red clover and timothy (Phlewm pratense) were also
attacked by a dry*spot disease which was apparently due to some
physiological condition of the soil.

A very full account is given of wart disease of potatoes (Syn-
chytrium endobioticum) and of the legislative and other measures
adopted for its control in Norway. The disease extends over an
area of about 30 by 10 km. in the region of Kristiansand. In 1921
the regulations in force since 1916, prohibiting the importation of
potatoes from Great Britain, Ireland, and Germany, were extended
to include Holland. The Ministry of Agriculture has further
decreed (August 1921) that consignments of potatoes shall only be
imported from other foreign countries when accompanied by a
permit issued by the proper authorities of the country of origin
vouching for the freedom of the consignments from wart disease.

Other potato diseases described, and in most cases illustrated, are
the various types of scab, Rhizoctonia solani, Sclerotinia libertiana,
blight (Phytophthora infestans), blackleg [Bacillus atrosepticus],
ring bacterial disease, dry rot [Fusarium caerulewm|], leaf roll, and
mosaic.

203

Leaf mould or rust (Cladosporiun fulvum), stem bacteriosis
(Bacillus solanacearum), blossom end rot (a bacterial disease), and
the black rot caused by Phomu destructiva and Rhizoctonia solani,
were observed on tomatoes, the last-named not being serious. Beets
were scabbed by Actinonyces sp. Club root (Plasmodiophoru
brassicae) occurred on cabbage and white mustard, soft rot (Bacillus
carotovorus) on turnip, and brown rot (Pseudomonas cainpestris)
was observed on all species of Brassica. On beans Ascochyta
holtshauseri [Stagonosporopsis hortensis|, Bacteriwm phaseoli, and
mosaic were amongst the diseases reported. Pythiwm de Baryanwinr
attacked seedlings of a number of different plants. Leaf spot of
cucumbers (Cladosporium cucumeriinui) did considerable damage
and also attacked melons, both hothouse and outdoor plants being
affected.

There are numerous other records of interest, and the report forms
a useful guide to the crop diseases of Norway.

Tempany (H. A.). Annual Report on the Department of Agri-
culture, Mauritius, for the year 1921, 21 pp., 1922.

The Report contains the following references to matters of
phytopathological interest. Root disease of sugar-cane occurred on
one estate in the Pamplemousses area, but was suppressed by the
treatment recommended by the Department of Agriculture. Other
bacterial and fungous diseases of sugar-cane were rare, and mosaic
disease has so far not been found in Mauritius.

Late planted potato fields were severely damaged by blight
(Phytophthora tifestans).

Field investigations on the ‘smut’ disease of filaos (Casuarina
equisetifolia) were continued in conjunction with the Forest Depart-
ment. Filao blanc was attacked by Corticiuim salmonicolor, reported
for the first time on this host, though previously found attacking
apples and pears.

Cultivated Chenopodiwm [goosefoot] at Réduit was attacked by
downy mildew (Peroinospora sp.).

Citrus plants at the Réduit Central Experiment Station were
found to be infected by canker (Pseudomonas citri), and lime trees
at Belle Rive and Pamplemousses were attacked by a specific
bacillus which invaded the bark, causing gummosis of the trunk
and the subsequent death of the trees.

Report on the Agricultural Department, Government of the Gold
Coast, for the year 1921, 77 pp., 1922.

The reorganization of the department has led to the grouping of
the two mycologists, two entomologists, and the chemist in a
Research Branch at Aburi, Mr. R. H. Bunting, the Assistant Director
for Research and Mycologist, being placed in general charge of the
work of this branch. Mr. H. A. Dade joined the staff as Assistant
Mycologist during the year.

The investigation of the new disease of cacao reported in 1919
under the name ‘mealy pod’ [a technical account of which is being
prepared for publication elsewhere] was continued. It is caused by
a fungus of considerable scientific interest, the systematic position
of which was difficult to fix. Preliminary infection experiments

204

indicate that the organism is sometimes capable of infecting un-
wounded pods which have been detached from the tree, and that
wounded or weak pods are much more liable to attack in the field
than vigorous ones.

A severe epidemic of black pod disease of cacao [Phytophthora
faberi| occurred on the banks of the Birrim River, causing a decay
of 99 per cent. of the pods in some plantations. Characteristic
sporangia were observed on numerous pods, both harvested and on
the trees. The outbreak was probably due mainly to the failure to
collect the pods during the previous slump in the local cacao market,
though excessive moisture may have aggravated it. Passage of the
fungus from affected pods to the stem on which they are borne,
with resulting canker formation and liability to reinfect succeeding
crops, was demonstrated, and the importance of removing all diseased
pods clearly established. The disease may be controlled by proper
drainage and cultivation, thinning out, and the removal of excessive
shade. Ripe pods, healthy or diseased, should be removed from the
trees, diseased tissue on the stems excised, the wounds tarred, and
all diseased material burnt. Empty husks should be buried as soon
as possible. A circular urging native producers to take active
precautions against the spread of the disease has been distributed,
but legislative measures will probably be necessary to ensure
co-operative efforts in this direction.

The thread blights of permanent crops were investigated in the
Kibbi district. Cacao trees planted in heavy, wet soil appeared to
be particularly liable to white thread. The presence of horse-hair
blight is injurious on account of its interference with the natural
functions of the foliage, but the question of its parasitism has not
been definitely decided. These diseases may be controlled by
improving soil conditions (tillage, drainage, and the like) and by
cutting out and burning all affected parts.

Coons (G. H.). Diseases of field and vegetable crops in the United
States in 1921.—Plant Disease Bull. Supplement 22, pp.
255-414, 21 maps, 1922.

This annual review of the diseases of field and vegetable crops in
the United States has been prepared on the same lines as those of
fruit and nut crops, and cereal and forage crops, already noticed
[see this Review, i, pp. 376 and 424).

During the last few years the potato certification movement has
been considerably extended in the United States and Canada, with
the result that the progressive deterioration of potato varieties
brought about by disease has been partially arrested. Reports
from various States on the use of copper-lime dust as a substitute
for liquid Bordeaux mixture showed that there is a consistent
increase in yield of the dusted rows over checks. The increases,
however, are somewhat smaller than those obtained from Bordeaux
mixture. The experiments of 1922 indicate that copper-lime dusts
afford ample protection against late blight, but that against tip
burn, hopper burn, and flea beetles the protection is not so good as
by spraying. Although in 1920 late blight was prevalent, the
general high temperatures and drought prevailing in the early half
of the growing season operated to check the spread of the disease

EEE
72

205

in 1921. Mosaic, leaf roll, and allied diseases continue to be of
great interest to research workers, and at present occupy the
attention of many investigators.

The diseases of tomatoes, sweet potatoes, beans, onions, cruciferous
crops, and cucurbits are summarized, with notes on prevalence, dis-
tribution, losses, and any special points of interest. Sugar-cane
mosaic is stated by Brandes to occur in all the sugar-producing
districts of the world, with the possible exception of India. In the
United States the distribution is restricted to Louisiana, Alabama,
Georgia, Florida, and Mississippi.

Sections on the diseases of sugar beet, tobacco, and miscellaneous
vegetable crops complete the Bulletin, which is a mine of valuable
information.

Martin (G. H.). Diseases of forest and shade trees, ornamental
and miscellaneous plants in the United States in 1921.—
Plant Disease Bull. Supplement 23, pp. 415-488, 15 maps, 1922.

This summary has been compiled from reports furnished by
collaborators in the various States, specialists in the offices of Forest
Pathology and Blister Rust Control of the Bureau of Plant Industry,
articles in botanical journals, and special reporters. Owing to the
lack of available data it has been found necessary to issue the
information in list form, with only a few scattered notes on
the general distribution and prevalence of the disease mentioned.

Douglas fir (Pseudotsuga taxifolia) was very generally and
severely attacked by V'rametes pini, causing ‘conk’ rot which
extends throughout the tree; Polyporus schweinitzii, producing
red-brown butt rot; Fomes luricis, causing brown trunk rot; and
F, roseus, the cause of yellow-brown top rot. These four fungi are
responsible for practically all the decay occurring in the Douglas
fir, which sometimes amounts to 50 per cent. of the stand or more.

White pine (Pinus strobus) suffers chiefly from the blister rust
(Cronartiuim ribicola). The co-operation between the New England
States, New York, Wisconsin, and Minnesota on the one hand, and
the Bureau of Plant Industry on the other, which was in force
from 1917 to 1921, resulted in the development of practical local
control measures. ‘The widespread application of the latter is the
object of the continued co-operation between these States and the
Federal Government. Special blister rust experts have been
appointed by the Bureau of Plant Industry to work in co-operation
with the State Forestry Departments and the State Agricultural
Extension Divisions. Under average conditions the safeguarding
of pine stands can be effected by the removal of currant and goose-
berry bushes to a distance of 900 ft. Cultivated black currants,
however, which are the most heavily infected of all the species of
Ribes, have been known to transmit the disease to pines more than
one and a half miles away.

Poplars, especially in Utah, are being rapidly destroyed by
canker (Cytospora chrysosperma), which is widely distributed in
the south-western States. The varieties affected are Populus alba
holleana, P. nigra, P. carolina, and P. tremuloides.

This annual publication of the United States Plant Disease
Survey is particularly useful in bringing together the numerous

206

scattered records of parasitic fungi found on trees, shrubs, and
ornamental plants during the year.

JARDINE (J. T.). Director’s Biennial Report: Oregon Agricultural
Experiment Station, 1920-1922, 104 pp., 1922.

In the Report of the Department of Botany and Plant Pathology
(pp. 72-75), reference is made to several matters of phytopatho-
logical interest in Oregon.

Anthracnose of apples [Veofabraea malicorticis|] is now being
controlled by the use of Bordeaux mixture in one of the late
codling moth sprays, thus effecting a saving of one spray application
annually for 20,000 acres of bearing trees.

Tests carried out in 1921 demonstrated that excellent control of
onion smut [Urocystis cepulae| on the most heavily contaminated
beaver-dam soil could be secured by the use of formalin (1 oz. to
1 gall. water), provided a stream of not less than five-sixteenths of
an inch in diameter is run into the furrow as the seed is dropped.
In one plot so treated the yield amounted to 364 sacks per acre as
against 884 sacks in the untreated control,

The preliminary results of an investigation of the ‘take-all’
disease of wheat [Ophiobolus cariceti] in the Willamette Valley
show that climatic conditions exercise a very great influence on the
severity of the disease.

Co-operative experimental work with the Federal Department
demonstrated the risk of seed injury from the ordinary formalin
and copper sulphate dips used against bunt of wheat | 7’i//etea], and
proved the value of a subsequent milk-of-lime bath to counteract
much of the damage [see this Review, i, pp. 298, 378]. The results
of further tests showed that practically no injury to wheat seed-
grain occurs after dusting with powdered copper carbonate, which
gives satisfactory bunt control. It is estimated that about 50,000
bushels of seed grain per annum are destroyed by injurious treat-
ment in one county of Oregon alone.

Investigations of potato wilt [Fusarium oxysporum and Verti-
cillium albo-atrum]| have proved the value of crop rotation and
tield roguing in the control of the disease. During the growing
season infection spreads. from plant to plant underground, so that
not only wilted plants themselves should be pulled up, but also
those next in the row on either side.

Pears and apples in Oregon have been widely attacked by
European canker [Vectria galligemt|, the diagnosis of which has
been facilitated by the discovery of the early spore stage in young
cankers [see this Review, i, p. 217]. The application of Bordeaux
mixture previous to the autumn rainy season is beneficial, and there
is reason to hope that the control of canker and anthracnose can be
accomplished by one and the same application,

AcrpaxaHckaa Cranuua Samus Pacrennii or Bpegureneii. [ Astra-
khan Plant Protection Station.] pp. 1-26, 1922.

We have received the report on the work of this Station during
1921, from which the difficulties arising from lack of experienced
personnel and shortage of material for combating insect and fungous
diseases of cultivated plants are plainly apparent. Particularly

207

serious in this part of Russia were attacks of Ustilago zeae on
maize, Tilletia tritici and Puccinia graminis on wheat, and Phyto-
bacter lycopersicum on tomatoes. With regard to the latter disease,
which in some cases destroyed the whole crop, the interesting
observation was made that it was most severe on land poorly irri-
gated owing to shortage of water supply; this appears to be in
contradiction to the general opinion that dampness of soil favours
development of the disease. Watering experiments made at the
Station in 1921 showed that while Phytobacter lycopersicum freely
attacked tomato plants watered from above by sprinkling, it seldom
appeared in plots watered by irrigation canals.

‘he Station publishes monthly leaflets dealing in a popular form
with the most important pests of cultivated plants in the region, of
which leafiets dealing with the following have reached us: Oidiwm
(Uncinula necator) of the vine; anthracnose (Colletotrichum oligo-
chaetum) of cucurbits; Oidiwm of cucumber, melon, watermelon,
and vegetable marrow; apple and pear scab (Musicladiwm dendri-
ticum and F. »irinwm); and Orobanche aegyptiaca. The last
causes much damage to cucumber, melon, watermelon, and tomato,
and also attacks cabbage and eggplants more rarely.

Corron (A. D.). Fungus diseases of crops 1920-1921.— Min.
Agric. Misc. Publ, 38, 104 pp., 1922.

The Ministry of Agriculture’s Report on the occurrence of fungous,
bacterial, and allied diseases of crops in England and Wales during
1920 and 1921 contains information invaluable both to the scientific
worker and the grower.

The cold, wet summer of 1920 and the exceptionally hot and dry
summer of 1921 provided excellent opportunities of gauging the
influence of weather conditions on plant diseases, and also of
judging to what extent one season’s weather affects the prevalence
and intensity of infection in the ensuing year. The total number
of diseases recorded was 391, of which 150 occurred on fruit, 82 on
vegetables, 40 on cereals, and 21 on potatoes.

Of an exhaustive and detailed report of this sort it is impossible
to give a brief summary, but a few points of special interest may
be mentioned.

In the wet spring and summer of 1920 late blight of potatoes
(Phytophthora infestans) was very severe in the south and west of
England and Wales, 50 per cent. of the tubers being infected in
many cases. The disease was reported from the Scillies on
15th April, the earliest date on record, but it did not spread ex-
tensively in England until June. The varieties that suffered least
were Kerr’s Pink, President, and Evergood, the first named being
immune, and the other two susceptible to wart disease.

In vivid contrast to 1920, late blight appeared phenomenally late
in the dry séason of 1921, the first record being on 25th July, and
its intensity was also exceedingly slight. The interesting fact was
discovered by Whitehead that in many cases the tubers of apparently
healthy plants were infected, sometimes as severely in 1921 as in
1920. ‘Trials by Lawrence are also reported which showed that by
pulling out haulms when blight was first seen in July a clean crop

208

was secured, whereas when the haulms were pulled out later, 40
and 75 per cent. infection occurred on Edzell Blue and Arran Chief
respectively. The advisability of adopting this treatment would
of course depend on the date of the attack and other circumstances.

Wart disease (Synchytrium endobioticum) was very prevalent in
the wet summer of 1920 and conspicuous by its absence in 1921.
The number of new outbreaks in 1920 was the lowest for many
years and that for 1921 lower still: several outbreaks, however,
occurred in neighbourhoods hitherto free from the disease. A series
of demonstrations was arranged in 1921 with the object of impress-
ing upon growers the serious nature of the leaf roll disease and the
value of healthy seed. The results showed that infected seed gave
only from 36 to 75 per cent. of the yield from healthy seed. Both
leaf roll and mosaic are more prevalent in the hot, dry parts of the
country than at high altitudes and in the north. In 1921 the
characteristic mottling caused by mosaic diseases was largely
obscured as a result of the heat and drought. Corky seab (Spongo-
spora subterranea), exceptionally bad in 1920 and almost absent in
1921, was successfully controlled at Leeds by Millard, who applied
flowers of sulphur at the rate of 6 ewt. per acre, and thereby reduced
the incidence of infection from 54 to 7-5 per cent. Seab (Acti-
nomyces scabies) is a disease of hot, dry seasons, and was very
prevalent in 1921. Millard has worked out a method of controlling
this disease by the use of green manure. Pink rot (Phytophthora
erythroseptica) was recorded for the first time in England in 1921.

Take all (Ophiobolus yraminis) |O. cariceti] caused serious
damage to wheat in five counties in 1920, and was present to a
slight extent in all parts of the country. The characteristic brown
mycelium was copiously developed at the base of the stem, at times
associated with a Fusarium. Perithecia were obtained on specimens
from Worcester in August.

A disease apparently identical with halo blight of oats (Bacteriwin
coronafaciens), though the causal organism has not yet been
isolated, was noticed in various localities, the damage sometimes
being severe. Crown rust of oats (Puccinia coronata) |P. lolii|
occurred with unprecedented severity in 1920, whereas in 1921 the
attack was almost negligible. Observations show clearly that this
rust overwinters in England in the uredospore stage on autumn-
sown oats. ‘The aecidial stage of the rust on Rhamivus cathartieus
is not uncommon in infected districts.

Mosaic disease of inangolds was recorded for the first time in
1920-21. The disease occurred generally in the eastern and
southern counties, and appeared in the crops about August, the
incidence of infection ranging from 1 to 95 per cent. Sugar-beet
was also slightly attacked by mosaic in 1921 in Nottinghamshire.

A bad attack of canker on frame and ridge cucumbers was re-
ported from Sussex in 1918, since when it has been impossible to
raise a normal crop in the infected localities. The causal fungus
was formerly believed to be Mycosphaerella citrullina, but subse-
quent investigation by Brooks led to its identification as a form of
Diplodina lycopersict.

There were no fresh cases of onion smut (Urocystis cepulae)
either in 1920 or 1921. Trials of eleven varieties of leeks at

209

Wylam showed all to be susceptible, but decidedly less so than
onions.

Apple mildew (Podosphaera lewcotricha) caused severe damage
in both years in spite of the marked climatic contrasts, and its
prevalence appears to be increasing. In Great Britain the disease
has hitherto been combated almost exclusively by pruning, but it
may be necessary to resort to spraying if it gains further ground.
Silver leaf (Stereum purpuwreum) became increasingly menacing
during the period under review, extending its ravages to the apple ;
many hundreds of apple trees were killed by it in some of the
eastern counties. The mode of infection and course of the disease
in apples correspond in all respects with those of the same disease
in plums. The prevention of unnecessary wounds, the tarring of
exposed surfaces, and strict attention to general cleanliness are the
only reliable control measures. Myxosporium canker (M. corti-
colum), well known in America, was recorded in England for the
first time by Wiltshire in 1920.

A die-back of plums caused by Diaporthe periniciosa [see this
Review, i, p. 63| was first observed in England by Miss D. M. Cayley
in 1919, and has since been under investigation. The disease pro-
duces symptoms somewhat similar to those of Cytospora, and it is
apparently widely distributed.

Weather charts of the temperature, rainfall, and sunshine for the
six meteorological provinces of England are appended, from which
it is possible to judge roughly the nature of the weather experienced
in any week of the year.

Meunts (I. E.), Drerz (8S. M.), & WILLey (FLORENCE). Alternate
hosts and biologic specialization of crown rust in America.—
Iowa Agric. Exper. Stat. Res. Bull. 72, pp. 211-236, 2 figs.,
1922.

Crown rust (Puccinia coronata) [P. loli] occurring on oats and
Calamagrostis canadensis may have as an alternate host any of
the American species of Rhamnus (R. lanceoluta, R. alnifolia, R.
caroliniana, R. californica, and R. purshiana) together with the
two imported species R. cathartica and R. frangula. The separa-
tion of P. coronata into two species, P. coronata and P. coronifera,
by Klebahn, and of these two species into four series, by Eriksson,
on the basis of the different species of Rhamnus used as alternate
hosts, is therefore not justifiable in America. Not all species of
Rhamnus are equally susceptible to the different biologic forms of
the rust. The forms occurring on Avena sativa, Culamagrostis
canadensis, and Festuca elatior preter those species of Rhumnus
most closely resembling R. cathurtica. Crown rust on A. sativa
produced normal aecidia on R. cathartica and R. lanceolata, both
of which may serve as important agents in the spread of the
disease.

In the oat-growing sections of the United States, the four most
common grass hosts of crown rust are Avena sativa, Calamagrostis
canadensis, Lolium perenne, and Holcus lanatus. The form of the
fungus on A. sativa is neither highly specialized nor limited in its
host range. The results of inoculation experiments showed that
species belonging to sixteen genera of grasses were susceptible to

E3

210

it. The form on Calamagrostis canadensis was found to have
susceptible hosts in fourteen genera. That on Loliwi is capable
of infecting thirteen genera; and eleven species in seven of these
genera gave full infection with this form. It is believed to be
possibly identical with that occurring on oats. On Holcus, on the
other hand, the rust was very highly specialized, Holcus being the
only grass fully infected amongst those tested with this biologic
form.

The forms of crown rust on Avena, Calamagrostis, Loliwm, and
Holcus may, under certain conditions, use the same hosts, but
manifest different degrees of infection. A. sativa was a common
host, but with varying degrees of infection, for all the forms of
crown rust studied.

Dave (H. A.). ‘Collar crack’: a new disease of Cocoa.—Jou7i.
Gold Coast Agric. and Commer. Soc., 1, 4, pp. 241-242, 1922.

Cacao plantations in Togoland were found to be attacked by an
unfamiliar disease which has been named ‘collar crack’ on account
of its very typical symptoms. Numerous radial cracks extend
upwards for about 2 ft. from the collar or base of the trunk, causing
injuries which generally result in the death of the tree. The cracks
are marked externally by a narrow, frilly outgrowth of leathery,
brown, fungous tissue. On felling the tree the cracks are found to
extend to the middle of the trunk, and to be packed with compact
plates of mycelium. The fructifications of the fungus, apparently
a species of Tricholoma, appear on the collar, close to the ground,
as a bunch of wet, soft, rusty-brown sporophores of the ‘mushroom ’
type. Each sporophore is 2 to 3 in. in height and 1-5 to 2 in. across
the cap.

The dllase occurred on farms which were situated in hilly rain
forest, and were suffering from the consequences of systematic
neglect. The humidity of the atmosphere was intensified by a
dense growth of low bush round the trees, which maintained the
collars in a permanently soaking state.

It is recommended that infected trees should be dug out and
burnt and the holes well limed. Thorough cultivation is con-
sidered to be the best preventive measure.

GRIFFEE (F.). Breeding Oats resistant to stem rust.—Journ. of
Heredity, xiii, 4, pp. 187-190, 3 figs., 1922.

In the work of breeding cereals for rust resistance at the Minne-
sota Agricultural Experiment Station, the purity of the F, plants
is determined on the basis of F; seedling tests made in the green-
house before the date of sowing the field plots. The method is well
illustrated by the results obtained in greenhouse tests used in
breeding oats resistant to stem rust, Puccinia graminis. In 1921,

600 F,, plants, which appeared resistant to rust under an artificially
induced field epidemic, were harvested at University Farm. These
plants were part of the progeny of the crosses of White Russian,
a resistant variety, with Victory and Minota, both susceptible. As
shown by Garber (Journ. Amer. Soc. Agron., xii, pp. 41-48, 1921),
the F, generation in these crosses is as resistant as the White
Russian parent, while in the F, generation segregation is in the

211

simple ratio of 3 resistant to 1 susceptible. A family of F, seedlings
was grown from each of the 600 F,, plants mentioned above, twenty-
five kernels of each plant being reserved for the 1922 field planting
and twenty-five or thirty of the remaining kernels planted in the
greenhouse. The kernels from the same plant were planted together
in a 4-inch pot. The seedlings were inoculated with stem rust, and
notes were taken about a fortnight later on the type of infection
obtained. Pots of White Russian and Victory seedlings were tested
along with each series of hybrid material and the type of infection
determined.

Under greenhouse conditions the inoculations resulted in a 4+
type of infection [see this Review, ii, p. 158] on Victory, the highest
obtained with any variety. With White Russian a 3+type was
obtained, though under the most favourable artificial epidemic con-
ditions in the field this variety never gives more than numerous
small uredosori, and natural infection, even in years of severe rust
epidemics, leaves it comparatively free from rust.

The number of F,, families which bred true for resistance in the
greenhouse approximated to expectations. In the cross White
Russian x Victory, 82 F, families out of 229 tested bred true for
rust resistance. This gives a ratio of 1-07 :1-93, which is very close
to the anticipated 1:2 ratio. In the cross Minota x White Russian
and the reciprocal, 110 families out of 338 tested bred true for rust
resistance, namely a ratio of 1-01: 1-99.

Since it is possible in this manner to identify large numbers of
homozygous resistant plants in the F, generation, the heterozygous
F, plants may be eliminated from the field sowings.

Two methods of seedling inoculation were employed, namely
ordinary inoculation and the brushing system. In the latter, which
proved uniformly preferable, the seedlings are sprayed with water
and brushed lightly with rusted seedlings. The incubation period
is the same in each case.

WEBER (G.F.). Septoria diseases of cereals. II. Septoria diseases
of Wheat.—Phytopath., xii, 12, pp. 537-585, 4 pl., 16 figs., 1922.

In continuation of the author’s studies on cereal diseases caused
by species of Septoria [see this Review, ii, p. 159] two diseases of
wheat, termed respectively ‘glume blotch’ and ‘speckled leaf
blotch’ are described.

_Glume blotch is caused by Septoria nodorwm Berk. |S. gluimarwin
Pass., Macrophoma hennebergii (Kuehn) Berl. & Vog.| and is known
in Europe, the United States, and Australia. It is common especially
in the southern and east-central States, where severe attacks may
reduce the yield by 50 per cent.

All the aerial parts of the plant are subject to attack. On the
glumes small, irregular, brownish spots appear, in which black
pyenidia develop. Infection may spread, in favourable conditions,
to the rachis and culm. On the leaves the spots are yellowish,
then dry up and become lighter in colour, a few scattered pyenidia
appearing on both surfaces. In severe attacks the leaf may be
killed.

The morphology and cultural characters of the fungus are
described in great detail. Conidia were produced laterally, usually

212

ut the septa of germinating pycnospores, on oatmeal agar, and were
oblong,. hyaline, 3-septate, and 18 to 32 by 2 to 4y. Perithecia
were found in the field, and compared with other collections of an
ascigerous stage found associated with S. nodorum, but the genetic
connexion of the pyenidial and perithecial stages was not established
by cultures. The perithecia probably belonged to the genus Lepto-
sphaeria. The optimum temperature for growth in culture was
20° to 24°C.

The fungus proved capable of infecting all the species of Triticwm
tested, and also rye and Poa pratensis. The pyenospores remain
viable in the pyenidia through the winter with little loss of
germinating power. More than 30 per cent. germinated after
eighteen months in the open. They are killed very easily by
drying and by the action of direct sunlight. In Wisconsin infection
of the leaves may be found from April and of the glumes from
June. Infection occurs by direct penetration of the cuticle, the
hyphae passing between the epidermal cells and remaining confined
to the intercellular spaces of the parenchyma. Spots first appear
in six or seven days and mature pycnidia, which always develop in
the sub-stomatal chamber, in twelve to sixteen days. Severely
infected plants are stunted and the ears empty or with only a few
shrivelled grains. Infection at the nodes appears to have a marked
stunting eftect.

In the second disease, as the name ‘speckled leaf blotch’ indi-
cates, the spots are characteristically speckled from the presence of
dark brown or black pyenidia in great numbers in the light-
coloured, dead tissues. These belong to the fungus Septoria tritice
Desm., which the author considers to be quite distinct from S/S.
gramineum Desm. No ascigerous stage was found. The fungus
is widely distributed in Europe, Asia, Australia, and America ; in
Wisconsin it may be found in almost every field of winter wheat.
Where infection is severe many seedlings are killed and the new
tillers formed during the winter and spring are also often killed.
Later in the season the losses from attacks on older parts of the
plant are negligible.

On the seedlings circular or oval spots develop on the leaves,
gradually spreading so as to involve the whole surface. The other
parts of the plant are not attacked. Pycnidia are found in quanti-
ties on the spots or covering the entire leaf surface. On older
plants the spread of the disease is usually slight and few new spots
appear after the flowering stage.

The fungus is variable. In cultures the growth may be hyaline
or dark, while the spores vary in size on the host plant according
to the period of the year, those formed in the winter being cossider-
ably larger than the summer ones. Conidia are numerous in culture
and were also found on artificially inoculated plants. They resemble
the pyenospores closely. The optimum temperature for growth is
22° C. to 26°C.

S. tritici infects the leaves of the same hosts as S. nodorum.
All the other plants tested were immune. It overwinters on winter’
wheat and in the pyenidial stage, the pyenospores remaining viable
in the pyenidia for over a year. The incubation period is about
six or seven days for the first spotting, and eleven to fifteen days

213

for the development of mature pycnidia. The method of infection
and pathological histology are much the same as in S. nodorwm.
No haustoria were found.

BRANSTETTER (DB. B.). Fungi internal to Missouri seed Corn of
1921.—Journ. Amer. Soc. Agron., xiv, 9, pp. 354-357, 1922.

Samples of 1921 seed maize from different parts of Missouri were
examined for the presence of internal fungi. After surface sterili-
zation in 1 in 1,000 mercuric chloride solution and thorough washing
with sterile water, the tips of the kernels were planted in Petri
dishes on potato- dextrose agar and incubated for twenty to thirty
days at about 25°C. The ears from which the kernels were taken
were arranged in two groups according to the severity of the
disease symptoms. The first group (badly diseased ears) contained
nearly twice as many kernels infected with Diplodia zeae and
Fusarium moniliforme as the second group (apparently disease-
free. ears). The latter group, however, contained many more
kernels infected with Cephalosporiwm sacchari. Only one culture
of Gibberela sauwbinetit: was obtained from more than 1,600
plantings.

Of the 192 seed ears examined, only nineteen appeared completely
clean and healthy. Nine of these ears were disease-free w hen
tested in culture, and only four showed as much as 50 per cent.
infection. On the other hand, the ears selected for their diseased
appearance generally showed 100 per cent. infection of the grain.

Me tuts (I. E.) & DuRRELL (L. W.). Dry rot of Corn.—Jowa Agric.
Exper. Stat. Cire. 78, 3 pp., 8 figs., 1922

Germination tests of thousands ae amie of seed maize on Iowa
farms indicate that a large proportion is unfit for sowing, chiefly
owing to the ravages of the dry rot fungus, Diplodia zeae, “the life-
history of which is described in this paper. In the autumn of
1921 mouldy maize was common throughout Iowa. High tempera-
ture and rainfall, which favour the development of the fungus,
were combined in the central and eastern parts, where the damage
from dry rot was estimated at 5 to 20 per cent.

The fungus attacks all parts of the plant. Infected roots and
stem nodes ' exhibit a dark brown discoloration; the shanks of the
ears break readily, and in some cases the fungus works up into the
butt. It may also attack the tip, entering from the silk. In other
cases the husks catch and hold the spores and infection results.
The mycelium grows freely in the tissues of the cob, causing a
brown discoloration of affected parts. Infected ears are of little
use for seed, and should be kept for fodder.

There is no consistent evidence that the mycelium habitually
travels from the soil to the ears inside the stalk. Recent studies
showed that 39 per cent. of the infected ears were borne on healthy
stalks. The fungus is only known to attack field and sweet maize.
The minimum temperature for growth is 40° F., the maximum
90° F., and the optimum 80° to 86°F. When the maize is dried
the fungus lies dormant, but will grow again when moisture is
supplied.

The modified rag doll germinator gives ve ry good results in tests

214

for germinating strength, but a glass-topped sand-box germinator,
though somewhat more expensive, is superior, bemg free from the
limitations incidental to the former method. The practical applica-
tion of both these methods of determining the degree of infection
is described in detail.

ZADE (A.), Experimentelle Untersuchungen iiber die Infektion
des Hafers durch den Haferflugbrand (Ustilago avenae Jens.).
[Experimental investigations of the infection of Oats by loose
smut (Ustilago avenae Jens.).|—Fiihlings landw. Zeit., 1xxi,
21-22, pp. 393-406, 4 figs., 1922.

The author believes that infection of oat seedlings with Ustilago
avenae rarely occurs from spores of the fungus that have adhered
to the outside of the glumes. His attempts to secure infection by
heavy application of spores on the exterior of the glumes did not
give an appreciable amount of smut. Further experiments, in
which the spores were applied after the glumes had been removed,
gave better results; it is evident that spores that have penetrated
between the glumes can cause infection, though the degree of
infection was not sufficient to account for the frequency of epidemic
attacks of the disease.

Tests made by applying spores to the ears during flowering
revealed the interesting fact that almost all the spores that fell on
the stigma began to germinate in 15 to 20 hours in mild, damp
weather. The promycelia formed tended to be unusually long, but
were otherwise normal and bore budding sporidia. The latter gave
rise to hyphae which came in contact with the mner wall of the
glumes and formed a mycelium in the peripheral parenchyma of
the latter. There was no evidence of flower infection such as is
known in Ustilago tritici, the embryo remaining free from infection
and only the glumes being invaded. The author believes that this
mycelium and the secondary sporidia that are borne on the hyphae
on the inner surface of the glumes form the most important source
of infection in oat smut. For effective control by seed steeping it
is essential that the fungicide should penetrate within the glumes
and prevent infection of the young seedling from the fungus in this
situation.

Mote (D. C.). A new Orange pest in Arizona.—Monthly Bull.
Dept. Agric. California, xi, 8-9, pp. 628-633, 1922.

A recent examination of the Washington and Australia navel
oranges in the Salt River Valley, where the loss from dropping of
the fruit was stated to be above the normal, revealed the presence
of small, pink, lepidopterous larvae, associated with black rot caused
by the fungus Alternaria citri. The work of the larvae in the
oranges somewhat resembled that of the codling moth (Carpocapsa
pomonella) in the apple. The life-history and habits of the insect
(probably Myelovs sp.) are described. It is not yet known whether
it or the fungus is the primary cause of the damage, which is
serious. Pending the results of further investigations, the Arizona
Commission of Agriculture has prohibited the movement of navel
oranges from that State to California.

215

Simmonps (H. W.). Bud-rot disease of Coco-nuts in Piji.— Agric.
Cire. [Dept. of Agric. Fiji], 11, 3, pp. 89-40, 1922.

During the past eighteen months serious damage to coco-nut
palms in the Fiji Islands has been caused by bud rot. The disease
is almost entirely restricted to the wetter portions of the islands,
being rare on the coast and abundant along the inland foothills.
Trees from five to fifteen years of age are more susceptible to the
disease than older ones, though in one area of excessive rainfall
(Vanualevu) numerous trees of twenty to thirty-five years old were
attacked.

The first symptom is generally the wilting and falling over of
the central unopened ieaf of the tree, leaving an outer ring of
leaves and nuts which are gradually shed until only the bare pole
is left. An irregular, greenish-brown or yellow spot usually occurs
at the base of about the eighth leaf or flower spathe from the
central core, and a patch of decay extends from this to the central
portion of the stem, which is in a rotten and foul-smelling condition.
Indications were observed that infection starts at the leaf bases and
penetrates inwards, not through the outer, overlying leaf sheaths.
On the infected material submitted to the Imperial Bureau of
Mycology, a fungus agreeing in its mycelial characters with the
parasitic species of Phytophthora described as the cause of coco-nut
bud rot in other countries was found ramifying between the cells.
Exact identification was impossible in the absence of fructifications.

It is suggested that the spread of the disease is likely to be
assisted by the hurricanes which are frequent in Fiji. The spraying
of young trees, especially at the leaf bases, with a strong Bordeaux
mixture is recommended as a preventive. Once the tree is actually
attacked, however, it should be cut out and the head burnt
immediately.

Ex.iott (J. A.). A new Ascochyta disease of Cotton.—Arkaisus
Agric. Exper. Stat. Bull. 178, 18 pp., 4 pl., 1 fig., 1922.

The disease previously attributed to Phoma in a preliminary
paper which has already been noticed [see this Review, 1, p.59], has
now been found to be due to Ascochyta gossypii Syd., hitherto only
recorded from Kashmir, where it was collected in 1908.

The blight attacks all the aerial parts of the plant except the
blossoms, and is capable of infecting leaves, stems, or bolls without
any apparent previous wounding of the tissues. Under very humid
conditions the fungus invades the leaf tissues very rapidly, advanc-
ing 1 cm. or more in twenty-four hours, and producing greyish, water
soaked spots which, under slight pressure, break down into a pulpy
mass resembling vegetables destroyed by bacterial soft rot, In
drier weather the outer edge of the spot is reddish-brown, the cortex
being of a lighter colour.

The spots on the bolls and stems are generally darker than on
the leaves. Stem infections were much the most conspicuous
during the 1920 epidemic. The liver-coloured spots occurred
mainly at the bases of the leaf petioles, and seemed to centre round
the stipules. Longitudinal extension rapidly followed, the leaves
dying when the base of the petiole beeame involved. The girdling

216

of the stem resulted in desiccation and death of the parts above
the lesion. As the spots enlarged the centres disintegrated and
fell out, leaving only the bast fibres cf the bark crossing the lesions.

The spots on the bolls are usually similar to those on the stem,
except for the darker centres of the former. Shredding of the
diseased tissues is also less marked on the bolls. A dark green,
water soaked area occurs when there is a rapid advance of the
fungus, otherwise the border of the spots is dark brown. Drought
may check the external advance of the spot while the internal
attack continues, sometimes causing the sudden collapse of the
bolls. Mature lint is easily destroyed and, in half-open bolls, may
be full of the grey fruiting bodies of the fungus. In 1920 there
were no natural infections of the bolls, but artificial infections were
readily obtained by needle pricks. The resulting spots were found
to be identical with those occurring naturally on diseased cotton
plants collected in Arkansas in 1915 and preserved in the patho-
logical laboratory.

An extensive series of inoculation experiments was carried out
under varying conditions, the first spots appearing in from one and
a half to five days, and pycnidia about three days later. In the
field, leaf infections were successful only in a very humid atmosphere.
Natural infections took place during rainy weather in October on
the plants which had previously been inoculated, and on those
adjacent to them, the remainder of the crop not being affected.

During the winter the fungus was found to develop saprophyti-
cally on the infected plants, the pycnidia and their spores being
morphologically similar to those of the parasitic fungus. In the
following spring spores from these saprophytic colonies were
capable of infecting healthy seedlings on inoculation. Later on in
the summer of 1921 the disease became epidemic in the experi-
mental plot, and vigorous plants succumbed to the attack almost
as rapidly as pear twigs suffering from fireblight.

Examination of the tissues of the diseased plants showed that
the host cells gave normal staining reactions up to the limit of the
advance of the mycelium, while the middle lamellae were also
apparently unchanged. The main advance of the fungus was inter-
cellular, but the cells were subsequently invaded and destroyed by
the hyphae, and in young tissues the tracheae and wood cells were
also killed. The action of the fungus appeared to be identical on
the tissues of all parts of the plant. The older parts of the lesions
revealed very little mycelium, and nothing in the nature of a stroma
was formed. The mycelium was apparently most abundant near
the outer limit of advance through the host tissues. Closely behind
the outer limit the host tissues were collapsed and pyenidia occurred
in various stages of development. These results indicate a some-
what narrow zone of parasitism, and may explain the dependence
of the fungus upon weather conditions.

The disease apparently occurs only in central and west central
Arkansas. As the fungus can overwinter on dead stalks in the
field, the growth of some other crop for at least one season is
recommended on infected land. It is improbable that the disease
is carried over from year to year on the seed,as in the case of
anthracnose [Glomerella gossypitl.

217

Brown (J. G.). Black-arm of Cotton: a successful method of
control.— Arizona Agric. Exper. Stat. Timely Hints for
Farmers 142, 8 pp., 4 figs., 1922.

Black-arm of cotton (Bacterium malvacearum) is the cause otf
extensive losses to growers, the reduction in yield from the disease
in the United States being estimated in 1920 at 213,000 bales.
Affected plants may be recognized by the water soaked areas on the
stems and leaves of seedlings; in older plants the bolls are also
attacked. The spots or lesions, which darken with age, exude a
bacterial slime and the growth of the plant is checked. On the
stems the spots are generally longitudinal, and their appearance has
given rise to the term ‘ black-arm’; on the leaves they are triangular
or quadrilateral, hence the name ‘angular leaf spot’ by which the
disease is also known. On the bolls the spots are usually circular
and depressed at first, but later the shape is irregular.

The bacterium is carried on the seed, and its development is
favoured by warm, moist weather. The Egyptian and Sea Island
varieties are the most susceptible, while the upland types are com-
paratively resistant.

The disease may be controlled by immersion of the seed in
sulphuric acid for fifteen minutes. For each 100 lb. of seed,
approximately 3 galls. of concentrated sulphuric acid, chemically
pure, specific gravity 1-84, are required. This treatment has proved
extremely successful under Arizona conditions, one treated, 14-acre
field in the Salt River Valley being practically free from black-arm,
while another field on the same farm was so badly infected that
238 diseased plants were counted in one row, 35 rods in length.
The treatment also accelerates germination, and its general adoption
is strongly recommended.

BRANDES (E. W.). Onderzoek op grooten afstand betreffende de
verwelkingsziekte der Bananen. [An investigation at a
distance of the wilt disease of Bananas.]|—Teysmiannia, Xxxili,
7-8, pp. 294-297, 1922.

Referring to Géumann’s belief that the vascular or Panama
disease of bananas is caused by a bacterium, identical with or allied
to his Pseudomonas musae {see this Review, i, p. 225], the author
maintains the view that Fusariwim cubense is the primary agent.
He considers it evident from the published account of the Java
disease that the author is not familiar with the much more serious
wilt of the West Indies, and that the attempted comparisons in his
paper are based on insufficient study of the publications dealing
with Panama disease. Various statements regarding the latter, as
for instance that Brandes did not mention the existence of bacteria
in the diseased tissues, that he did not succeed in inoculating the
underground parts of the banana with F. cubense, that he used
diseased bananas for his experiments, and so on, are based on a
complete misunderstanding, as may be seen by reference to the
original paper in Phytopathology (ix, p. 339, 1919). Géumann’s
isolation of a weak bacterial parasite from wilted bananas in Java
is not in any way evidence that a bacterium is the primary cause
of the Panama disease.

Replying to the above criticisms (pp. 297-300), Giumann refers

218

to his successful inoculations of the rhizome, aerial stem, and leaves
of bananas with Ps. musae, and contrasts them with his own and
Brandes’s (Ann. Rep. Mich. Acad. Science, 1918, p. 273) failure to
secure the same results by direct inoculation of the above ground
parts with Fusarium. If the latter is really the primary cause of
Panama disease, why have all investigators failed in their attempts
at direct inoculation of healthy plants with the organism? It is
suggested that F. cubense is unable to develop in healthy tissues
and appears only when the latter are already discoloured by the
action of the bacterium. It may, therefore, be regarded as a
secondary organism, the strongly toxic properties of which produce
the typical symptoms of the later stages of the disease.

FERDINANDSEN (C.). Ueber einen Angriff von Krebs (Fusarium
willkommii Lindau) an Apfel- und Birnfriichten. [An attack
of canker (Fusarium willkommi Lindau) on Apple and Pear
fruits. |—Angew. Botan., iv, 4, pp. 1738-184, 3 pl, 1922.

In the autumn of 1919 fruits of pears in Denmark were attacked
by an unusual disease characterized by depressed, sharply defined,
brown spots originating on seab [Venturia pirina] wounds, and
spreading thence over the greater part of the fruits. In the spots
were numerous spore layers covered with hairs, white at first, after-
wards bare and greyish, and turning brownish when dried. Micro-
scopical examination showed that the fungus was indistinguishable
from Fusariwm willkommii, the conidial stage of Nectria galligena.
In 1920 the same disease was found on apples from two different
localities.

Inoculation experiments with conidia from naturally infected
pears, and also from pure cultures, produced the typical depressed
and rather dry, brown and soft rot on pear and apple fruits of
several varieties. In all cases the skin of the fruit was more or
less injured prior to inoculation. Further inoculations with pure
cultures of the fungus from pear and apple fruits were carried out
on branches, the fungus from each host being tested on both apple
and pear. They produced typical canker wounds bearing the fructi-
fications of F. willkommii. The inoculations were made through
deep cuts on the branches. The fungus was re-isolated from the
artificially infected pear branches, and inoculated into pear and
apple fruits, on which it again produced the typical soft rot. Re-
isolated from infected apple branches, the fungus produced soft rot
on pears, but the apples used in a similar experiment were destroyed
by Penicilliwm glaucum.

A further series of experiments with F. willkommii isolated from
natural canker wounds on an apple tree, showed that the fungus
was able to product a decay, corresponding to the soft rot here
described, on apple and pear fruits.

Coutpy (A. 8.). Limiting factors in Illinois Raspberry culture.—
Trans. Illinois State Hort. Soc., vi, pp. 837-841, 1922. }
Raspberry culture in Illinois has been declining in importance
for a number of years, partly as a result of disease. Crown gall
[| Bacterium tumefaciens| is rapidly suppressing the cultivation of
both black and red raspberries [Rubus occidentalis and R. idaeus].

219

The disease cannot be controlled by spraying, and infected nursery
stock is responsible for disseminating it widely. Nursery inspection
is fundamentally unreliable, as the disease does not necessarily
appear externally during the first season of attack. Anthracnose
[Gloeosporium venetum|, though widespread and destructive, can
be satisfactorily checked by two applications of lime-sulphur, one
of dormant strength when the leaves have expanded about one-
quarter of an inch, and one of summer strength when the shoots
are 6 to 8 inches in height. In a series of experiments at Peoria
in 1922 the ‘Rex’ brand of lime-sulphur was used (1 in 8 winter
and 1 in 40 summer strength). The mixture was applied very
thoroughly with a short spray rod (Myers hand pump) and Ver-
morel nozzle. Owing to the peculiarities of its bark, the blackeap
[| R. occidentalis] is difficult to spray, and the addition of a spreader,
such as casein, is recommended.

Eastern blue stem [see this Review, ii, p. 128] was observed for
the first time m Illinois during 1922. The field where the disease
was noticed was planted with Michigan nursery stock purchased
some years ago. Judging by the severity of the disease in Michi-
gan, a serious situation is likely to arise in Illinois, especially as
infection cannot be held in check by spraying. The berries pro-
duced are small and of inferior quality, and 10 per cent. more fruit
is required to fill a quart box from a diseased than from a healthy
bush. In order to prevent the further spread of the disease a
system of drastic roguing must be followed. The Michigan authori-
ties are making every effort to stamp out the disease in that State.

Roserts (J. W.) & Pierce (L.). The bacterial spot of Peach.—
Trans. Illinois State Hort. Soc., lvi, pp. 78-87, 1922.

Bacterial spot of peach [Pseudomonas pruni]|, the symptoms of
which are described, occurs in most of the peach-growing areas of
the United States, being especially severe in the southern districts.
Almost all varieties are attacked, the most susceptible being J. H.
Hale, Elberta, Carman, Champion, and Waddell. The control of
the disease presents considerable difficulties owing to the liability
of the trees to spray injury. Bordeaux mixture suppresses the
disease, but damages the foliage more severely than the bacillus
itself. Lime-sulphur compounds do not give control. The results
of the authors’ experiments in Arkansas showed that losses from
the disease can best be reduced by careful attention to pruning and
cultivation, and by fertilization with nitrate of soda (2 or 3 lb. per
tree). Treatment with bone meal and acid phosphate, though not
nearly so satisfactory as the nitrate applications, somewhat lessened
the amount of infection. .

Britton (W.E.), Zapper (M. P.), & Sropparp (E. M.). Experiments
in dusting versus spraying on Apples and Peaches in Con-
necticut in 1921.—Conn. Agric. Exper. Stat. Bull. 235,17 pp.,
6 pl., 3 figs., 1922.

Dusting experiments in comparison with spraying were con-
ducted in Connecticut in 1921 in four apple orchards and two peach
orchards. In each case two treatments were given after blossoming
on apples, and three on peaches.

220

The dusts used in the apple orchards were the sulphur-lead,
sulphur-lead-nicotine, and Sanders’ dusts, while the liquid spray
used for comparison in all apple orchards contained liquid lime-
sulphur, lead arsenate, and nicotine sulphate. In one apple orchard
comparative tests were made between dry lime-sulphur and liquid
lime-sulphur, B.T.S., and Bordeaux mixture, with lead arsenate
added to each. All the tests are described in considerable detail.
In nearly all cases the best results were obtained from the sprayed
plots, and the sprays were more effective than the dusts in con-
trolling fungous diseases. Both sprays and dusts adequately sup-
pressed codling moth and other chewing insects ; neither controlled
curculio. In the sprayed orchard, dry lime-sulphur gave a larger
percentage of good fruit than liquid lime-sulphur, B.T.S., or Bor-
deaux mixture. During 1921 the principal fungous diseases of
apples in the orchards under observation were scab | Ventwriu
inaequalis], black rot [Physalospora cydoniae], fruit speck, and
sooty blotch [ Leptothyrium pomi}.

On peaches the only spray used was atomic sulphur, and the
dusts were sulphur and sulphur-lime-lead arsenate. In all the
peach orchards the dusted plots gave slightly better fruit than
the sprayed ones. Peach scab [Cladosporium carpophilum]| and
brown rot [Sclerotinia fructigena] were controlled by both dusting
and spraying. Dusting is more costly than spraying both in peach
and apple orchards.

HOsTERMANN. Versuche iiber die Eignung neuer Pflanzenschutz-
mittel zur Bekampfung des Apfelmehltaues (Podosphaera
leucotricha). [Experiments on the efficacy of new plant pro-
tection methods for the control of Apple mildew (Podosphaera
leucotricha).|—Ber. héh. Gdrtnerlehranst. Berlin-Duhlem,1920—
21, pp. 96-97, 1922.

During 1920-21apple mildew occurred with unprecedented severity
in Germany. Dormant spraying was carried out with various fungi-
cides early in March in an orchard of ten year old espaliers, Lands-
berger Renettes grafted on Doucins. When the buds opened the
sprayed trees were found to be quite as badly infected as the un-
treated controls. These negative results were probably due to the
inability of the spray to penetrate the buds and thus reach the
overwintering mycelium, rather than to any lack of fungicidal
efficiency in the large number of mixtures used.

The summer treatment, which also comprised the principal up-to-
date fungicides, was applied in two separate series, on pruned and
unpruned trees. The effect on the latter was practically nil, but
a certain improvement was noticeable in the former, especially after
the use of solbar, colloidal sulphur (now known as ‘cosan’), and
lime-sulphur.

In a spraying experiment conducted in the Dahlem Horticultural
College orchard in the summer of 1920, colloidal sulphur (0-05 per
cent.), ‘Bordola’ sulphur (0-05 per cent.), and ‘ Prae’ sulphur (0-05
per cent.) gave satisfactory results, while uspulun not only failed
to control the disease, but also burnt the foliage.

The author concludes from the above results that winter spraying
against apple mildew is merely a useless expense, and that summer

221 '

treatment must be preceded. by thorough pruning. The use of
resistant varieties appears to be the only permanent means of
control.

SWINGLE (D. B.) & Morris (H. E.). The brown bark spot of fruit
trees.— Montana Agric. Exper. Stat. Bull. 146, 22 pp., 6 figs.,
1921. [Received 1923.]

The disease termed brown bark spot causes severe damage to
apple and pear trees, and has also been observed on peach, plum,
prune, and cherry, though it is seldom serious on stone fruits. It
has been known throughout western Montana since 1910, and also
occurs in Idaho, Oregon, and Washington. Recently specimens of
what is apparently the same disease have been received from
Japan.

The chief symptoms are the death of the buds on certain branches,
the appearance of elevated brown spots on the bark, which is killed,
and ultimately the death of the aerial parts of the tree. When the
buds of the apple are swelling and opening, a certain number are
found small, shrivelled, and dead. They may be confined to a single
shoot or extend over the whole tree. Those that die without
opening have a conspicuous, dark brown streak, running down
through the centre to the base. Frequently the bark around the
bud dies and becomes sunken. The fibro-vascular bundles that
extend through the bark from the leaf sears are blackened. A week
or two later small, raised, pimple-like spots, about $ inch in
diameter, appear on the bark of the youngest shoots. These are at
first of the same colour as the normal bark, but the centre soon
assumes a green, water soaked appearance and then turns brown.
The bark on the smaller diseased twigs shrivels and dies, but that
on larger branches (above 4 or 2 in. in diameter) may remain alive
and green for several weeks, though growth is checked.

Some weeks after these early symptoms, the brown spots typical
of the’disease develop on the larger branches and trunk up to 5 in.
in diameter. The spots are nearly circular and from 3} to 3 inches
across. They are elevated (,; to } inch in height), rather spongy
in texture, reddish-brown at the margin and mottled pale green
and brown inside. Later in the season they often crack away
from the surrounding bark. Above the spotted areas the branches
may be either entirely leafless or remain for some time apparently
normal and fully provided with leaves. Ultimately the bark dies
back progressively from the tips of the branches. Red-brown
streaks can usually be found in the cambium and inner bark long
before any external discoloration is visible. Sometimes young trees
are killed to within a few inches of the ground in a single season.
In less severe cases only a few limbs may be affected in the first
season, and partial recovery occurs occasionally. Complete recovery
is extremely rare. The bark of the root system is quite free from
any symptoms of the disease, and the roots are the last part of the
tree to die.

On pear trees the symptoms of brown bark spot differ in some
respects from those on the apple. After the death of the buds both
small and large spots appear on the bark, the colour of the large
ones being a very dark grey. The inner bark turns almost black,

222

and the cambium of limbs 4 to 2 inches in diameter is often black-
ened in streaks 1 to 3 feet long. The discoloration extends outward
half way through the bark as a mottling, the black mingling with
the normal whitish colour of the tissues.

In stone fruits the symptoms are generally similar to those
described above, but much less conspicuous owing to the fact that
the normal colour of the bark is almost identical with that of the
spots.

T Repadted attempts to isolate a causal organism from the diseased
tissues have given negative results, and the inoculation of healthy
trees with diseased bark also completely failed to reproduce the
symptoms. This evidence, though not absolutely conclusive, strongly
suggests the absence of any infective agent, and the fact that
affected trees are usually either isolated or in small groups favours
the theory that the disease is due to some fault in the chemical
composition of the soil.

It is difficult to suggest intelligent control measures without
more definite knowledge of the cause of the disease, but the authors
are convinced that, at any rate, the factor of contagion can be dis-
missed from consideration. On the hypothesis that the disease
may be due to infertility of the soil in respect of certain requisites
of plant food, possibly nitrogen and phosphorus, the application of
these elements is recommended. Top-working by means of grafting
and budding gave good results in certain cases. The disease occurs
both in irrigated and non-irrigated land, so that soil moisture can
be ruled out as a determining factor, and the same may be said of
climatic conditions. The chemical composition of the soil is at
present being investigated by the Chemistry Department of the
Experiment Station.

HOSTERMANN. Versuche zur Bekampfung der Kohlhernie (Plasmo-
diophora brassicae). [Experiments in the control of club
root of Cabbage (Plasmodiophora brassicae).|\—Ler. hih. Gart-
nerlehranst. Berlin-Dahlem, 1920-21, pp. 100-103, 1922.

Experiments in controlling Plasmodiophora brassicae by means
of uspulun were carried out in the summer seasons of 1920 and
1921. In the 1920 trials uspulun was applied to the infected soil
of the frames in the form of powder and its effect tested by growing
the following plants in the treated soil: mustard (Stnapis alba),
head cabbage, Brussels sprouts, kale, kohlrabi, red cabbage, cauli-
flower, and stocks [Matthiola]. Excellent results were obtained by
the application of 0-25, 0-5, 1, and 1-25 gm. of uspulun per litre of
soil (each frame containing 16 1. of soil), barely a trace of fection
being found in the first two cases and none at all in the others.
Quite satisfactory results also followed the application of only
0-1 gm. uspulun per litre of soil, the percentage of healthy plants
being very high as compared with the untreated controls, all of
which, except the stocks, were severely infected.

In 1921 uspulun was applied to the soil in the form of a liquid
spray (13 1. of a 0.25 per cent. solution per 8 1. of soil), the test
plants comprising red cabbage, kohlrabi, head cabbage, and mustard.
The results were not nearly so good as in the previous year, pro-
bably because the uspulun salts were retained in the upper layers

223

of the soil. In the case of mustard, the fungus appears to act as
a stimulant to growth, which is further promoted by the uspulun
treatments. The growth and seed production of diseased mustard
plants, especially when treated with uspulun, greatly exceeded
those of healthy ones.

Mustard was the most susceptible of the plants tested and stocks
the least. Head and red cabbage were the most resistant cabbage
varieties. Further tests in 1921 showed that when grown in heavily
infested, untreated soil the percentage of diseased plants of wall-
flower was 85, of stocks nil,and of shepherd’s purse (Capsella bursa-
pastoris) 62. The latter should therefore be eradicated from the
fields during the rotation.

JUNGE (E.). Praktische Massnahmen zur Bekampfung tierischer
und pflanzlicher Feinde. [Practical measures for the control
of animal and vegetable enemies. |—Ber. héh. staatl. Lehranst.
fiir Wein-, Obst-, und Gartenbaw zw Geisenheim-am-Rhevn
1920-21, pp. 28-29, 1922.

Fungous diseases were on the whole held in check in 1921 by the
protracted heat and drought. Apple mildew |Podosphaera leuco-
tricha|, however, was extremely severe, scarcely a single variety
being free from damage. The excision of affected shoots during
the winter proved useless, and the application of 10 per cent.
carbolineum in the middle of March also had no effect.

At the end of May experiments in the control of apple mildew
with solbar were begun. The leaves were then fully developed
and severely infected. A preliminary 1 per cent. application was
followed by spraying with a 2 per cent. mixture at fortnightly
intervals. Though not completely suppressed, the development of
the fungus was satisfactorily checked, and absolute control would
probably be ensured by starting the applications of solbar while
the trees are still dormant.

Both solbar and potassium sulphide gave good results in the
control of American gooseberry mildew | Sphaerotheca mors-uvue |.

HOSTERMANN. Zur Frage der Ueberwinterung des Apfelmehltaues.
(Podosphaera leucotricha). |The question of the overwinter-
ing of Apple mildew (Podosphaera leucotricha).|—Ber. hoh.
Gértnerlehranst. Berlin-Dahlem, 1920-21, pp. 97-98, 1922.

In January, 1922, shoots of espalier apple trees which had
suffered severely from mildew in the preceding summer were
gathered, immersed in warm water (35°C.), and then immediately
sprayed with ‘cellocresol’ 2-5 per cent. (Saccharinfabrik, Magde-
burg), solbar 5 per cent. (Bayer, Leverkusen), ‘ Nosperal’ 2 per cent.
(Meister, Lucius & Briining Dyeworks, Hoéchst-am-Main), a new
{unnamed ] organic copper preparation 2 per cent., and ‘ Dendrin’
2-5 per cent. (Avenarius). The shoots were then placed in a green-
house where re-infection with apple mildew was extremely im-
probable. Under these conditions the buds opened and most of
them were attacked by mildew, irrespective of the fungicides used.

This confirms the results of previous tests [see above p. 220],
which indicate that winter spraying is of no avail, the myceliwn

EOE

224.

being situated in the interior of the bud, and therefore out of reach
of the fungicide.

Geurina (A.) & BROTHUHN (G.). Ueber die Wirkung verschiedener
Beizmittel auf Riiben. I. Beizversuche mit Germisan. [The
effect of various disinfectants on Beets. I. Disinfection ex-
periments with germisan.|—Fii/lings landw. Zeit., xxi, 15-16,
pp. 281-289, 1922. 3

The results of repeated tests in the disinfection of beet seed
against root rot (Pythium de Baryanwm and Phoma betue) carried
on at the Brunswick Agricultural Experiment Station, showed that
in sandy soil, steeping in germisan considerably delayed germination,
whereas in clay soil it accelerated germination at a strength of
0-1 per cent., and did not appreciably delay it at any concentration
up to 0-5 per cent. Root rot was very satisfactorily controlled ‘by
germisan (0-25 to 1 per cent.) and uspulun (0-25 per cent.). ‘Se-
getan’ also gave good results, especially in respect of increased
germination ; it did not control root rot quite as completely as the
other two disinfectants.

OBERSTEIN. Saatbeizapparat-Ausstellung, [Exhibition of seed
disinfection apparatus.|—Angew. Botan., iv, 4, pp. 185-190,
2 pl., 1922.

At a special exhibition of seed disinfection apparatus at Breslau
in May 1922, several interesting machines were shown. It is
pointed out that a good apparatus must absolutely free the grain
from unbroken bunt balls, which are a common source of reinfection
of wheat with Tilletia tritici. It must also remove the air from
the hairs and furrows of wheat and from between the glumes of
oats. Not only must light grain be separated (particularly neces-
sary in seed treatment against Pusariwin and Helminthosporiwie
diseases), but also the seeds of certain weeds that are so light as to
be difficult to remove by sifting. Finally it must be easily adjusted
for the prescribed periods of treatment and be easy to clean.

Two chief types of construction appear to have been exhibited.
In one the grain is fed in and removed either by a continuous
screw or a scoop; in the other it is placed in an inner, tipping,
vessel which can be dipped into and removed from the outer vessel
filled with the steep.

In all cases the best results in removing unbroken bunt balls,
light grain, and weed seeds are got when the container is first filled
to overflowing with the liquid and the grain then fed into it, a
large surface being provided for the overflow which carries off the
light seed and débris. The grain must on no account be poured in-
before the container is filled, as once the bunt balls have been
completely immersed they do not rise so readily to the surface.

For removing air the continuous screw apparatus provided
sufficient movement in some machines, while in others the grain is
stirred vigorously with a horizontal bladed paddle or a stream of
compressed air blown through it.

In timing the treatment the screw principle is the easier, but
gives less accurate timing and less thorough work than the double

225
container, and this advantage of the latter may be considered to
balance the extra trouble in working it.
No details of the construction of the machines are given.

Rurtu (W. A.) & Ketty (W. W.). Recent advances in spraying.—
Trans. Illinois State Hort. Soc., vi, pp. 90-103, 3 figs., 1922.

Amongst the improvements in spraying practice that the authors
are convinced, both from an examination of the work of other
investigators and their own extensive Jaboratory experiments, are
most urgently needed are the use of heavier applications of the
spray fluid and the finding of a substitute for lime-sulphur. The
latter is stated to be proving injurious in many cases.

The use of spreaders has already done much to overcome difficul-
ties in application due to lack of adhesion of the spray to the
surface sprayed. By the addition of casein-lime to lime-sulphur
a perfect covering for peaches is formed, and this spreader also
increases the adhesiveness of Bordeaux mixture on plums. More
spray also adheres to apple shoots dipped into winter strength lime-
sulphur when casein-lime is added. It was found that immersion
of peach shoots for one minute in the lime-suiphur and casein-lime
solution ensured greater adhesiveness than when the immersion
lasted about a second. Similar time effects, as well as increased
adhesiveness from the use of casein-lime, were observed when
sections of radish leaves were immersed in Bordeaux mixture. The
results of orchard experiments on Ben Davis, Winesap, and Grimes
apples showed that the addition of casein-lime to the lime-sulphur
mixture appreciably reduced the amount of spray necessary. It
also greatly assisted in the formation of a film over the fruit, which
was most difficult to secure without it. The authors’ experimental
work has shown, however, that, on most surfaces, casein-lime does
not noticeably increase the proportion of spray retained unless
prolonged drenching is practised. It may just as well be omitted
from light or moderate applications.

Another recent development of some importance is the introduc-
tion of ‘ wettable’ sulphur, made by adding casein-lime to very
finely ground sulphur. This will be used extensively in eastern
peach-growing districts as a substitute for self-boiled lime-sulphur.
Probably only sufficient lime should be used to dissolve the casein
(about twice the dry weight of the latter) as there are good reasons
to suppose that lime itself sometimes causes injury by increasing
fruit drop.

CHEVALIER (A.), Sur une maladie de la Lavande cultivée. |A
disease of cultivated Lavender.|--Rev. Bot. appliquée, ii, 18,
pp. 482-483, 1922.

In June 1922 the author found an interesting disease in a planta-
tion of lavender (Lavandula vera), about 20 hect. in extent, situated
at an altitude of 750 m. near the mouth of the Rhone. Both aspic
(Lavandula latifolia) and true lavender (L. vera) occur in a wild
form in the neighbourhood, and some plants of L. fragrans and L.
delphinensis have been imported into the district.

The affected plants were found to be completely withered. On
the surface of the large roots, bundles of white mycelial hyphae

226

could be observed, and similar hyphae were found invading all the
underground portions of the plant. The fructifications of a small
Agaric were found on one of the tap-roots on a slight protuberance
near the collar. The fungus was identified by Patouillard as Pho-
liota praecox, a species which has not hitherto been known to cause
damage to cultivated plants.

It is suggested that the disease may be controlled by thorough
sanitation, including such measures as ‘burning the affected plants
and draining the low-lying parts of the plantation.

Revue bibliographique des travaux mycologiques publiées en 1920.
[Bibliographical survey of mycological works published in
1920.]—Bull. Soc. Myc. de France, xxxviii (Supplement), 123
pp., 1922.

By means of a subsidy granted by the Fédération francaise des
Socictés de Sciences naturelles, the Mycological Society of France
has arranged to publish an annual bibliographical survey of French
and foreign mycological literature. The present fascicle, which is
the first of the series, contains classified lists of mycological litera-
ture published during 1920. New genera and species are mentioned
and brief abstracts are given of most of the papers cited.

SHEAR (C. L.). Life-history of an undescribed ascomycete isolated
from a granular mycetoma of Man.—WMycologia, xiv, 5,
pp. 289-248, 3 figs., 1922.

The author gives a short description, with a diagnosis, of a pleo-
morphic fungus which was isolated in 1921 by Dr. M. F. Boyd,
Galveston, Texas, from a granular mycetoma in a human ankle,
and was sent to him for identification. The lesion had lasted, with
intervals of temporary healing, for about twelve years, and was the
result of a wound inflicted by a thorn in the sole of the foot. As
the fungus does not appear to be an anaerobic organism, it is not
quite clear how it could live and develop within the tissues during
the long periods when the wound was closed. Inoculation experi-
ments with pure cultures conducted by Dr. Boyd on guinea-pigs
were not successful in producing pathological effects of the mycetoma
type.

The fungus develops readily on ordinary culture media, and in
a few weeks produces all the spore forms. On cornmeal agar the
colonies are white at first, then grey and with a radiate, fimbriate
margin. As conidia develop the colour becomes greenish-ochre,
then smoky brown. The first conidia are borne on loosely branched,
byssoid hyphae, on short lateral or terminal sporophores. They
are of the Cephalosporiwm type, with hyaline (later yellowish-
brown), continuous, rather variable conidia, 8 to 15 by 4 to 7-5 p,
borne in groups at the tips of the conidiophores. Later a coremial
stage of the Dendrostilbella type develops, with a dark brown syn-
nema, 200 to 300» in height, and with a subglobose fertile head
bearing conidia like those of the first form. Perithecia are found
in numbers on the surface of the medium, and are globose, mem-
branous, dark brown, without ostiole, and 100 to 200 « in diameter.
The asci are globose, thin-walled, evanescent at maturity, 8-spored,
and measure 10 to 20; paraphyses are absent. The ascospores

227

are globose or somewhat ovoid, continuous, smooth, pale yellowish-
brown when ripe, and 7 by 7, or 5-5 to 7 by 4 to 4-5 yu.

The fungus is most closely related to the organism described by
Costantin (Bull. Soc. Bot. France, xl, 2nd ser., 15, pp. 236-288,
1893) as Hurotiopsis gayoni, and renamed by Saccardo Allescheria
gayont. It is regarded as a new species, and named A. boydii, the
names Cephalosporiwm boydii and Dendrostilbella boydii being
given to the two conidial stages described.

NELSON (R.). The occurrence of protozoa in plants affected with
mosaic and related diseases.— Michigan Agric. Exper. Stat.
Tech. Bull. 58, 28 pp., 18 figs., 1922. [Received March 1923.]

This interesting paper records the occurrence of biflagellates in
bean and clover plants affected with mosaic, and of trypanosome-
like organisms in tomatoes with mosaic and potatoes with leaf roll.
It is copiously illustrated with photomicrographs depicting the
different organisms described and their situation in the tissues.

In a brief introductory summary the author alludes to the general
belief in the filter-passing nature of the organisms causing mosaic
diseases, to the recent discoveries by Matz, Kunkel, and Palm of
foreign bodies in the cells of affected plants, and to the indication
that the phloem is the region where the exciting cause is situated.
He considers that there is little justification for the belief that filter-
able forms alone represent the stages of the parasites that are
capable of producing these diseases, in view of the possibility that
they are caused by protozoa, and the known extreme polymorphism
of many of these.

The main object of the investigations was to determine if any
organism could be demonstrated in the phloem tissue of mosaic
plants. Bean mosaic was readily obtainable owing to the investiga-
tions of this disease carried on at the station for several years past.
Clover and tomato mosaics were plentiful in the neighbourhood,
while sufficient potato leaf roll for preliminary work was also
available.

In all the early work the ordinary botanical methods were fol-
lowed, but they revealed nothing. Protozoological methods, modified
for plant material, were then adopted and applied to longitudinal
sections, a departure from the customary technique of examining
transverse sections which the author believes would have illuminated
the mosaic problem if employed earlier.

In bean mosaic the sieve tubes were found to be remarkably free
from staining particles, and to afford excellent material for study.
Longitudinal sections of affected stems or petioles, fixed in various
standard solutions of mercuric chloride and stained with Heiden-
hain’s iron-alum haemotoxylin, show the constant occurrence of
biflagellate organisms scattered throughout the sieve tubes and
phloem parenchyma. Tissues of healthy plants showed no such
organisms.

Various forms have been observed in diseased tissues. (1) The
most common type were large, elongated, tapering, or cigar-shaped
individuals resembling Leptomonas in shape, but with two flagella,
one at each pole. (2) Ovaliform biflagellates of the same type.
(3) Deep-staining, slightly elongated, or almost spherical, sometimes

228

paired, bodies, surrounded by a lighter envelope which is penetrated
by the flagella. (4) Very small, elongated flagellates, probably
very young , forms of type (1). (5) Deeply stained, oval bodies with
degenerate. flagella and outer envelope, perhaps encysted forms.
(6) Small, elongated, non-flagellate bodies varying very much in
size and occurring in great numbers in the degenerate chloroplasts
of the subepidermal cells or filling the lumen of these cells.

Most of these flagellates lie close to the nucleus and parallel to
the long axis of the host cell, although smaller forms sometimes lie
obliquely. The flagella, which may be medial or slightly lateral,
and which appear to be attached to deeply staining granules, are
usually extended, but may be coiled round the nucleus. Degenerate
nuclei are often found in diseased tissue.

The biflagellate forms divide by simple, longitudinal, binary
fission. First the basal granules divide, next the flagella split, a
V-shape slit appears in each end of the body, and division then
occurs. Other forms of division probably exist, but have not been
observed.

The organisms have been demonstrated in living material by
cutting thin longitudinal sections through the phloem, mounting
immediately in boiled water, and examining under high-power, dry
lenses with minimum illumination. The flagellates were seen
actively motile in the sieve tubes, whirling rapidly but without
much displacement of position. Rarely more than one individual
occurs in a cell, and many cells have none.

The juice expressed from short pieces of petiole was also examined
as hanging drops under oil immersion lenses. Occasionally organ-
isms were seen to flash across the field, but they were not located
easily.

The size of the flagellates is very variable; type (1) ranges in
length from 18 to 5y (average 13-5) and in breadth from 3-9 to
0-3; pw. The flagella may vary “from 18 to 7-2 p

Mosaic of clover (transmissible from bean si vice versa) is also
associated with the presence of flagellates of the same type as those
found in bean mosaic. Non-flagellate forms were more frequent
than flagellate ones, while besides type (1) the small biflagellate
forms, and occasionally the broad form, found in the bean were
also demonstrated.

No great difficulty was encountered in locating, in the sieve tubes
of tomato mosaic material, organisms with a deep staining, long,
sinuous, tapering body of trypaniform nature, with one or both
ends drawn out to a fine point, and usually with one end larger
than the other. The organisms hold haematoxylin tenaciously, and
usually lie close to the nucleus. They are not so numerous as those
in the bean, seeming to occur in ‘nests’, the larger forms undoubt-
edly splitting into a number of smaller individuals. Binary fission
was observed in several cases, but only of small forms.

Besides the long, sinuous type of organism, shorter and broader
forms also occur, while many show only a shght undulation and
others are almost straight. The phenomenon of ag gglomeration (two
or more organisms attached to each other by their posterior ends),
common among trypanosomes, has been observed in the organisms
in tomato mosaic.

229

In size the tomato organisms vary widely, the average being 15-5

_by 2-8y. The largest individual seen was 27 by 6y, and the
smallest 6-2 by 0-5. The small forms have been seen passing

through the perforations in the sieve plates. No definite flagella
have been demonstrated, but an undulating membrane has some-
times been seen faintly stained and running nearly the entire length
of the body. A nucleus can be made out in the centre of the
organism, and deeply staining granules near the extremities.

In potato plants showing only leaf roll symptoms, long trypano-
some-like organisms were found in the sieve tubes of the petioles
and stems. They vary, but are nevertheless characteristic and
constant for this disease. They tend to distribute themselves along
only certain of the sieve tubes, but when present they usually occur
in a succession of cells. They are frequently in intimate contact
with the nucleus, although they may le free in the cell, usually
parallel to the long axis, or, in the case of the smaller forms,
obliquely. In size they vary from 35 to 11-3, or less in length,
and 3-0 to 0-9 4 in breadth, the average being 23-6 by 1:8. The
organisms appear to possess a distinct undulating membrane,
especially in certain extremely sinuous individuals, and occasionally
a long flagellum at one end of the body has been seen. Distinct,
dark staining granules occur at each end of the body and are
probably blepharoplasts.

In conclusion, the author discusses the nature of the organisms
found, emphasizing their protozoon characters, and on the present
evidence tentatively suggests that the bean and ciover organisms
belong to a new genus related to the species of Leptomonas found
in the latex of Euphorbiaceae and Asclepiadaceae, but distinguished
by the bipolar flagella, whilst the resemblance between the organism
of tomato mosaic, and especially that of leaf roll of potato to try-
panosomes, is unmistakable. As regards the ability of viruses to
pass bacterial filters, some of the very slender forms of the bean
flagellate might pass medium filters, and there is the possibility of
‘symplastic ’ forms occurring in the life-cycle.

FRANCHINI (G.). Essais d’inoculations aux souris blanches du
latex parasité de différentes espéces d’Euphorbes. [Inocula-
tion experiments on white mice with parasitized latex from
different species of Euphorbiaceae. |—Ann. Inst. Pastewr, xxxvi,
12, pp. 873-881, 1922.

Of about thirty mice inoculated in the peritoneum with the latex
of various species of Euphorbiaceae containing trypanosomes and
amoebae, only seven were slightly infected. The animals were
subsequently destroyed, and an examination of the organs of the
infected individuals revealed a few Leishmaniform or oval bodies,
some provided with a short flagellum, while others contained several
nuclei and centrosomes. The organs of a mouse inoculated with
the latex of Kxcdecaria emarginata contained more protozoa than
the others. The organisms were free or, rarely, intra-corpuscular.
Cultures on Ndéller’s medium yielded a large number of protozoa of
various kinds, especially some with pseudopodia and pronounced
amoeboid movements. Phagocytosis of the red corpuscles occurred
in some instances.

230

FRANCHINI (G.). Essais @’inoculation au chat d’amibes du latex
de plantes. [Inoculation experiments on the cat with amoebae
from the latex of plants. |—Budll. Soc. Path. exot., xv, 10, pp. 931—
933, 1 fig., 1922.

In the summer of 1922 three young cats were inoculated with
cultures of amoebae from the latex of Acokanthera veneneta,
Plumeria alba, and Ficus carica respectively. In the two first
cases slight infection resulted, with phagocytosis of the red corpuscles
by some of the amoebae. Both the animals were indisposed for
a short time. The third experiment gave entirely negative results.

These observations corroborate those of Musgrave and Clegg,
who successfully infected two out of three monkeys at Manila with
cultures of amoebae from lettuce leaves.

Nistkapo (Y.) & Miyake (C.). Studies on the Helminthosporiose
of the Rice plant.—Ber. Ohura list. landiw. Forschuigen, ii,
2, pp. 133-194, 9 pl., 1922.

A brief historical account of the rice disease caused by Helimin-
thosporium oryzae, which is common in Japan, is given. The first
mention of a Helminthosporiwm on rice in Japan was made in 1895
by Miura, who attributed the disease to H. macrocarpum Grev.
In 1901, however, Hori stated, as a result of his investigations, that
the disease was caused by a new species, H. oryzae Miyabe and
Hori. The present authors are satisfied that the fungus with which
they have worked is identical with H. oryzue M. & H., and that
Miura’s species was the same. In 1918 Hara suggested that the
name H. oryzae Breda de Haan should take precedence of H. oryzae
M. & H. on grounds of priority, Breda de Haan’s description having
been published in Java in 1900. Although it has not been possible
definitely to ascertain that the Java species is identical with that
occurring in Japan, available data indicate that this is the case.
The name H. oryzae Breda de Haan has therefore been adopted in
the present paper. Apart from H. ivacrocarpum, which is suffi-
ciently like H. oryzae to have led to confusion, but which differs in
the size and shape of the conidia and conidiophores, there are two
other allied species parasitic on rice, namely H. sigmoideun Cav.
and H. maculans Catt., both of which, however, are easily dis-
tinguishable morphologically from H. oryzae.

The symptoms of the disease appear first on the foliage, whence
they rapidly extend to all the aerial parts of the plant. Numerous
small brown spots, the size of a pin’s heaa and more distinct on
the lower than on the upper surface, develop. The spots, which
‘are first visible 24 to 48 hours after infection, gradually enlarge
and become dark brown, measuring at this stage 1-5 to 2 mm. by
0-5 to 0-75 mm. in diameter, and being surrounded by a yellowish
halo. They finally attain a length of 5 mm. and assume irregular
shapes owing to coalescence. The central part of the spot turns
grey, and heavily infected leaves gradually die back from the tip.
The dead portions of the leaves have a velvety appearance caused
by the conidiophores of the fungus. Seedlings are attacked as soon
as they reach a height of 2 to 3 cm. The tips of the first leaves
turn brown, and spots appear on the blades. In the authors’
germination tests 12-5 per cent. of the seedlings were affected in

2al

this way. Serious infection at an early stage results in a blight of
the culms, which turn yellow and then dark brown, the surface
being covered with velvety conidiophores. In such cases the heads
are sometimes unable to emerge from the leaf-sheaths. In later
infections, after the ears develop in the early autumn, lesions are
observed on the lowest joint of the rachis, the brown or greyish-
brown spots being up to 40 mm. in length. These neck lesions
resemble those due to Piricularia oryzae, but may be distinguished
from the latter by their lighter colour, velvety surface, and the
wider curve of the infected head. On the glumes, the lesions
generally begin near the joint of the outer and inner glumes, and
spread over the entire surface. Infected glumes are covered with
blackish-brown hairs.

The morphological characters of the fungus are fully described.
On the host, the conidiophores are stout, erect hyphae arising in
tufts of two to five or more, usually through a stoma, but sometimes
through the epidermis or from mycelial hyphae on the surface of
an infected grain or leaf. They are constricted at the point of
passage through the epidermis or at the point of branching from
creeping hyphae, and expanded into a swelling above the constric-
tion. They are occasionally branched at the base, very slightly
constricted at the septa, dark olive below and paler towards the
apex, sometimes curved, and geniculate. Their size ranges from
68 to 688 in length, mostly from 172 to 47384. In width they
range from 7-6 to 20 » at the base, and the minimum and maximum
number of septa observed were 2 and 26 respectively.

Conidia are produced singly on the tips of the conidiophores.
They vary in length from 15 to 132 4 and in width from 10 to 26 p
the mean being about 74 by 17 yw. They are generally obclavate,
rounded at the basal end, attenuated towards the apex, and curved
to one side, but they may be cylindrical or long elliptical and
straight. The septa vary from 1 to 12 in number, and the colour
from deep olive-buff to greyish-olive. The basal end of the conidium
is marked by a small dark scar, where it was inserted on the
conidiophore.

In culture the number of conidiophores and conidia produced by
the various strains varied greatly. From one to ten or more
conidia may be borne on the conidiophore. They attain their full
size within two days. The cultural characteristics of the fungus
on a number of different media are described at some length. Good
growth was obtained from a culture two years and seven months old.

The results of inoculation experiments showed that a large
number of grasses can be successfully infected by H. oryzae. In
the authors’ experiments and those quoted from other Japanese
publications, some fifty species belonging to thirty-two genera were
found to be susceptible. These included maize, sorghum, barley, Cota
lucryma-jobi, Panicum crus-galli, P. miliaceum, P. sanguinale,
Hleusine indica, Setaria italica, S. glauca, and Cynodon dactylon.

The mechanism of penetration was studied. It was found that
the germ-tubes from germinating conidia are surrounded by a thick,
mucilaginous sheath which causes the germ-tube to adhere to the
epidermis of the host plant or, when grown in culture, to the glass.
Appressoria are formed at the tips of the germ-tube within three

2032

hours after germination. The tips swell up and become lobed or
variously branched. Penetration can occur either through the
stomata or through the cuticle and epidermal wall, by a thin infec-
tive hypha arising from the appressorium. The latter is often not
well marked in the case of stomatal infections.

The optimum temperature for the germination of conidia was
found to be between 25° and 30°C., the minimum and maximum
temperatures being 2° and 41° respectively. The optimum tempera-
ture for mycelial development was 27° to 30°C. The thermal
death point in ten minutes’ exposures was 50° to 51° for conidia
and 48° to 50° for the mycelium.

As the control of the disease by seed treatment has been dealt
with in an earlier paper, only a brief discussion of the fungicidal
effects of various substances on the conidia of H. oryzae is given.
The following showed a comparatively high degree of efficiency:
mercuric chloride, silver nitrate, copper sulphate, caletum hypo-
chlorite, formaldehyde, and phenol. Particulars are given of the
concentrations required in each case, and the length of exposure
necessary for the destruction of the fungus.

SHARPLEs (A.). A consideration of recent work on the brown bast
problem.—Malayan Agric. Journ., x, 6, pp. 155-170, 1922.

After a brief reference to the formation in 1918 of the Brown
Bast of Rubber Investigation Committee in Malaya, the author’
gives a comparative résumé of the work done contemporaneously
by the Committee in Malaya and by Rands in Java who, in many
eases, followed parallel lines of investigation [see this Review, 1,
pp. 187-142].

In the course of experiments carried out by members of the
Committee a large number of different organisms, a list of which
is given, was isolated from tissues of Hevea affected with brown
bast. The total failure, however, of numerous inoculation trials
and attempts to transfer brown bast by transplanting and grafting
diseased bark on to healthy trees, even though successful grafts
were obtained, tends to support Belgrave’s view, shared also by
Rands, that brown bast is a non-infectious disease of physiological
origin. Keuchenius has steadily supported the opposite view of
a possible bacterial origin of the disease [see this Review, i, p. 263].
In this he is evidently much influenced by the results of experi-
ments in which he made forty inoculations with bacteria isolated from
the diseased tissues and kept forty controls. In both, discolorations
progressing from the point of inoculation were obtained, the total
length of the discolorations in the inoculated series being 177-5 em.,
against 59-5 cm. in the controls. An analysis of these results shows,
however, that twenty of the bacterial inoculations showed an
increase in the length of discoloration as compared with the controls,
while in sixteen there was no difference from the controls, and in
the remaining four the length of discoloration was actually less
than in the controls, The author therefore suggests as the only
logical conclusion that such results cancel out and need not influence
the work of other investigators. Furthermore Rands failed to get
any positive results with bacteria supplied by Keuchenius, and the

233

various bacteria isolated from diseased bark in Malaya have equally
failed to reproduce the disease.

A series of experiments set up by the Committee to test the
comparative effect of tapping daily, on alternate days, and every
third day on a full spiral, a half spiral, and a quarter cut, the results
of which are given in tabular form, confirmed the evidence collected
by Rands that heavy tapping raises the percentage of brown bast
very considerably. The alternate day tapping resulted in much
lower percentage of the disease than daily tapping, while tapping
every third day gave still less. It was further observed that a
single cut of extreme length, as for instance on a full spiral, gives
similar results to a number of shorter cuts.

The evidence supplied by experiments carried out during a period
of two years in Malaya, some details of which are given, does not
support Rands’s assumption that the resistance to brown bast some-
times observed in high-yielding trees, which he believes are generally
the most susceptible to the disease, might be due to specific im-
munity, and that it might be possible by selection to breed a strain
of Hevea brasiliensis immune to the disease. From the Malayan
work it would appear that there is little relation between yield and
the number of trees attacked by brown bast, though the progress
of the disease is slow on bad soil (e.g. old tapioca land) where
growth is poor and the cortex is tough. The existence of specific
immunity is likely to be difficult to establish in view of the fact
that general conditions of growth affect the percentage development
of brown bast to a very great extent, and that the progeny of trees
selected for their resistance may, therefore, vary in their suscepti-
bility according to the set of conditions under which they are
grown. Moreover, in seed selection as so far practised on rubber
plantations, little attention has been given to the possibility of the
male parent influencing the results.

The remainder of the paper is a short review of the methods of
prevention and treatment of brown bast advocated in Malaya and
elsewhere, and a consideration of the histological features of diseased
tissues in which the opinion is expressed that too much importance
has been assigned to the phloem changes observed by Farmer and
Horne [see this Review, i, p. 144.

WaAkKsMAN (S. A.). A method for counting the number of fungi in
the soil.— Journ. of Bact., vii, 3, pp. 339-341, 1922.

The probable error involved in the determination of the numbers
of soil fungi by the ordinary plate method is so great as to render
the results quite worthless, the development of most of the fungi
being prevented by that of the large number of bacteria on the
plate when sufficient concentrations of soil to ensure the presence
of fungi are used. The following synthetic medium has therefore
been devised, its reaction being sufficiently acid to inhibit the
development of the species of Actinomyces and the majority of
bacteria: glucose 10 gm., peptone 5 gm., KH, PO, 1 gm., MgSO,.7H,O
0-5 gm., and distilled water 1,00V¢c. Dissolve by boiling, add
enough N/1 acid (H,SO, or H,PO,) to bring the reaction to P;, = 3-6
to 3-8 (12 to 15 cc. of N/1 acid per litre of medium). Add 25 gm. of

234

agar, boil, filter, run into tubes, and sterilize as usual. The final
reaction should be Py = 4-0. .

The soil should be diluted only one-fiftieth or one-two-hundredth
as much as the dilutions used for the determination of bacteria
(e. g. instead of a dilution of 1 to 200,000, 1 to 4,000 or 1,000 should
be used), and plates are prepared in the regular way and incubated
for 72 hours at 25°C. To obtain an accurate count and a low
probable error ten plates should be prepared in each series. The
colonies may be counted after 48 and again after 72 hours, by which
time the spreading forms, occurring in soils rich in Mucorales, tend
to overgrow the plate.

McWuorvter (I. P.). The nature of the organism found in the
Fiji galls of Sugar-cane.—Philippine Agriculturist, xi, 4,
pp. 103-111, 2 pl., 2 figs., 1922.

After a brief reference to the work of other investigators, the
author describes successful preliminary attempts to cultivate the
organism found in the galls of the Fiji disease of sugar-cane.
Hanging-drop cultures were made in cane juice from thin sections
containing the cysts of the organism. The percentage that germi-
nated under such conditions was, however, very low, only about 2
per cent. giving really good germination.

The organism can first be demonstrated in the cells of the
developing galls, where it appears in the form of irregularly shaped,
Jobed, amoeboid bodies, varying greatly in size and composed of
granular protoplasm in which the granules are more or less equally
distributed with little or no differentiation of ectoplasm. One to
six bodies are present in each cell, three being a very frequent
number. One (or sometimes more) is generally attached to the host
nucleus and remains so until a fairly advanced stage in the life-
history of the organism ; in some cases, however, the host nucleus
may disintegrate as maturity is reached. The larger individuals in
the cells may fragment into several smaller ones or, more frequently,
divide by a primitive mitotic division into two equal parts. Stained
preparations of this stage show that the fragmenting bodies contain
nuclei without any nuclear membrane and in a stage of chromidial
fragmentation typical of amoebae. During this amoeboid stage the
galls continue to develop. The division of the organism is accom-
panied by the division of the host nuclei; the latter being more
frequently amitotic than mitotic. As the galls get older and their
walls begin to thicken, the amoeboid bodies cease to divide; they
then begin to show vacuoles in their cytoplasm, and finally all sizes
round up into eysts. During the early stages of vacuolation, the
small cysts resemble certain of the ‘ring stages’ developed by the
sporozoa, and are strikingly similar in appearance to young Ent-

amoeba coli. The author observed no indication that the large

amoebae divide into a mass of spores. Each cyst is formed from
a single amoeba, and since the amoebae differ in size, so do the
cysts. The mature cyst is a hollow structure, composed of highly
vacuolate protoplasm with a firm but not brittle wall.

Besides bearing galls, plants suffering from Fiji disease are
dwarfed, and show other symptoms of disease. In such plants it is
not difficult to demonstrate various forms of the organism in other

235

parts besides the galls. Partially encysted stages may be occasion-
ally found in the metaxylem; the author has found them in the
metaxylem of the roots in plants with a very typical reduced root
system. In swollen places on these roots, which are really galls,
the organism often occurs in abundance.

When germinating, the wall of the eyst softens, generally irregu-
larly so that lobes are formed as in a moving Avrcel/a. Then the
granules composing the walls of the vacuoles are rearranged, and
the cyst becomes transformed into a typical motile amoeba, with
one or more slowly contractile vacuoles and both rounded and
pointed pseudopodia. ‘There is little differentiation into ectoplasm
and endoplasm, but in all cases a distinct, highly refractive body,
probably a nucleus, is present. Since each cyst changes into only
one amoeba and each amoeba has a single nucleus, it is likely that
the cysts are uninucleate, though this point requires further inves-
tigation. Although the wall of the cyst must contain much meta-
plasm, the organism was never observed, when germinating, to
make any attempts to shed the wall, which becomes part of the
motile amoeba’s protoplasm. Movement is sluggish, and the amoebae
show a tendency to become pointed in culture, though nothing
resembling a flagellum has been seen. The amoebae that develop
from the large cysts differ but little from the smaller ones, except
in size. The maximum length observed was about 15 p, but the
average is only about 5y. When dividing, the smaller forms
frequently assume a peculiar trypanosome-like shape. Figures
showing the amoebae dividing into two of approximately equal size
are given from cultures. Summing up, the life-cycle of the organism
is simply amoeba—cyst—amoeba. The cysts represent a resting,
non-motile stage in the life-history of the organism, and cannot be
considered a method of reproduction.

Discussing the classification of the organism, the author states
that it differs widely from the genus Plasimodiophoru in showing
no tendency to coalesce into a true plasmodium, in the absence of
a zoospore stage, in the spores (cysts) being large, variable in size,
and absorbing their membranes when germinating. Among the
Chytridiaceae, the fungus Asterocystis vadicis, causing flax root-
blight, has spores that might be mistaken for cysts of the Fiji
organism, but the fact that it reproduces chiefly by means of
numerous swarm spores clearly ditferentiates it from the latter.
The author concludes that the organism in the Fiji galls is an
amoeba related by its characteristics and method of encystment to
the section Lobosa, although he can find no previous record of such
an organism parasitic on plants. The Fiji amoeba resembles Ent-
amoeba coli, but differs from the genus Entamoeba by its nuclear
behaviour and the germination of its cysts. Since there is appa-
rently no existing genus wherein it may be placed, he proposes the
generic name Phytumoeba. Lyon’s name Northiella sacchari [see
this Review, i, p. 187] is not accepted.

The following is the diagnosis of the organism: Phytanvoeba
g.nov. Small intracellular amoebae capable of living in a free
state. Little differentiation of ectoplasm. Pseudopodia lobose,
blunt. Reproduction by gemmation and simple fission. Cysts
form in host cell. Each cyst develops into one amoeba. No zoo-

236

spores. P. succhari sp.nov. Small intracellular amoeba, capable
of living in free state. Size variable, seldom more than 12 yp.
When intracellular, pseudopodia are lobose or pointed. Vacuoles
present, more or less contractile in extracellular type. Nucleus
organized or distributed. Cysts small, rounded, highly vacuolate,
walls smooth. Cysts germinate into amoebae. Reproduction by
gemmation and simple fission. No zoospores. No coalescing of
amoebae to form large plasmodia. Host Saccharum officinarwm
Linn.

Inoculation experiments are in progress. With regard to the
path of the organism there is evidence that it passes partly through
the metaxylem and partly through certain cells of the pericycle
lying between the xylem and phloem. This would help to account
for the fact that the galls generally develop from that region of the
pericycle. The author has little doubt that the disease is insect
borne, though this important point remains to be demonstrated.

WILBRINK (G.). Een onderzoek naar de verbreiding der gelestre-
penziekte door bladluizen. | An investigation of the transmis-
sion of yellow stripe disease by green- lies] —Meded. Proefstat.
Java Suikerind., 1922, 10. [ Reprinted from Arch. Suikerind.
Nederl.-Indie, xxx, pp. 418-456, 1922].

After a preliminary account of the symptoms and distribution
of yellow stripe or mosaic disease of sugar-cane, the author describes
certain investigations and experiments bearing on Brandes’s dis-
covery that the disease is transmissible by insects from sorghum to
sugar-cane and maize.

In January, 1921, attempts were made to get the disease to pass
from sugar-cane, maize, and sorghum plants infested with Aphis
adusta (A. maydis) to healthy sugar-cane plosts, but all the experi-
ments gave negative results. In January, 1922, however, A. adusta
was again observed on young sugar-cane interplanted with maize,
and the author found that by interplanting the cane with any of
the favourite hosts of A. adustu the transmission of the disease
could easily be secured. In addition to the hosts of A. adusta
already enumerated in the literature [see this Revievw, ii, pp. 83-34],
the following have recently been found: Sacc harwm spontaneum,
Dacts tylocteniwm aegyptiacum [Hleusine aegyptiacu|, and Penni-
setuin macrostachyum. Under Java conditions the insects appear
to prefer Panicum colonum to any other host.

A. succhari attacks primarily the Black Cheribon, White Preanger,
Black Borneo, and EK 28 varieties of sugar-cane, and, in contrast
to A. adusta, inhabits by preference the older leaves. The only
alternative host in Java appears to be sorghum, on which the insects
are present in enormous numbers. A pink variety of A. sacchari,
however, was also found to attack Panicum colonum.

In June, 1921, sorghum plants growing close to infected sugar-
canes became diseased, and in the autumn of 1921 and 1922 further
cases of infected sorghum were observed, both among the plants
adjacent to diseased sugar-canes and in those planted next to
diseased sorghum. Neither the infected sorghum plants nor the
wild hosts were seriously affected by the disease, growth being
unimpaired and the setting of seed normal. Maize interplanted

237

with diseased sugar-cane in December 1921 became infected in
January 1922. The light and dark spots were small at first, but
the former rapidly extended so that the leaves finally showed
scattered green spots on a yellow or light green ground. Develop-
ment was not appreciably impaired, and the seed of the diseased
maize gave healthy plants, as was also the case with sorghum.

The results of a series of comparative experiments, in which
infected and healthy sugar-cane seedlings were enclosed in cages
with A. sacchari and A. adusta, respectively, showed that, in the
case of the former, transmission of the disease from infected to
healthy plants occurred only in one instance (the authenticity of
which was questionable), while in the latter series transmission
occurred very generally (100 per cent. of the healthy plants be-
coming infected in one case) and the role of A. adusta in the process
was unmistakable. These results confirm the work of Brandes,
and also show that the disease is transmissible from infected ‘to
healthy sugar-cane, as well as from sorghum to cane and maize.

The bearing of this work on the incidence and control of the
disease is discussed at length. Damp and cloudy weather indirectly
favours the propagation of A. adusta by promoting the growth in
the cane fields of the wild grasses among which it finds so many
hosts. Similar results are produced by light and fertile soils.
Now that the infectious character of the disease has been fully
established, the most stringent measures must be adopted to secure
the cultivation exclusively of disease-free setts. The nurseries
from which cane for planting out is obtained [see this Review, i,
p- 187] should be carefully watched, and every case of the disease
immediately removed and destroyed. The growth of grasses should
be prevented in all nurseries. Susceptible varieties, if cultivated
at all, should be restricted to absolutely isolated fields, but it is
better, whenever possible, to replace them by resistant varieties,
amongst which 100 PO J appears to be one of the best, while 247 B,
E K 2, and EK 28 are also mentioned.

TANAKA (T.). New Japanese fungi. Notes and translations.
XII.— Mycologia, xiv, 5, pp. 282-295, 1922.

This number of the series contains the diagnoses in English,
together with notes, of several Japanese species of Gym nospor-
angium that have been described in publications written in
Japanese. In each case the synonymy and full bibliographical
references are given.

Gym nosporangiwin asiaticum Miyabe forms its teleuto stage on
Juniperus chinensis and J. chinensis var. procumbens (sarge nti)
and the aecidial stage on Pyrus sinensis and Cydonia vulgaris.
The Roestelia form of this fungus (R. koreaensis) causes the very
destructive rust of the Japanese sand-pear, but European pears
suffer little from natural infection though they can be inoculated.
Some Japanese authors mention Pyrus toringo and Cydoniu
sinensis as further hosts. Gymmnosporungium yamadae Miyabe
has its teleuto stage on the same hosts as the last, while the
aecidial stage causes an apple rust that has menaced the apple
cultivation of northern Japan. It also attacks Pyrus spectubilis
and P. toringo. Gymnosporangium idetae Yamada is found in

238

the teleuto stage on Juniperus rigidus and in the aecidial form on
Amelanchier asiatica. Gymnosporangiwim hemisphaericum K.
Hara occurs on Juniperus littoralis (J. conferta) and J. chinensis
in the teleuto stage and on Pyrus zum in the aecidial. Gyimno-
sporangium shiracanwin K. Hara forms teleutospores on Juniperus
littoralis and aecidia on Pyrus sinensis. Sand-pear cultivation in
the Mikatagahara region had to be abandoned owing to the
virulence of this rust.

The paper terminates with a synopsis of the Japanese species
of Gymunosporangium hitherto recorded.

Hara (K.). On Witches’ Broom of the Sasa spiculosa.—Jouwri.
Agric. Soc, Shizuobaken, 300, 5 pp., 2 pl., 1922. [Japanese. ]

A new witches’ broom is described and figured on the Sasa
bamboo, The English diagnosis is as follows: Lpichloe saswe
Hara n.sp. Stroma surrounding the young sheath, cylindrical or
conical, pointed at the top, 1-5 to 4 em. long, 3 to 5-5 mm. thick,
black, pulvinate, hard when dry; perithecia immersed, elliptical or
ovate, 250 to 350, high, 110 to 200, broad, with projecting
ostiola ; asci cylindrical, eight-spored, 200 to 250 by 6 to 7 w; spores
filiform, hyaline, 190 to 240 by 1 to 1-5, septate at maturity,
separating at the septa into short segments, 12 to 17 4 Jong. Hab.
on Susa spiculosa (Province Idzu, Nekko, 1922).

SoutH (F. W.). Regulations controlling the importation of plants
into the Straits Settlements, the Federated Malay States,
and Johore.— Malay Agric. Journ., X, 9, pp. 228-238, 1922.

The object of this article is to present in a concise form the
various regulations controlling the importation of plants into the
Straits Settlements, the Federated Malay States, and Johore. The
regulations which have appeared at irregular intervals in different
Government Gazettes are not readily accessible.

The entry into the Straits Settlements of the following plants is
subject to control.

Coco-nuTs. The importation of all coco-nuts and other palms
from Ceylon, Sarawak, and the Philippine Islands is prohibited.
This regulation does not apply to nuts of the coco-nut or betel-nut
palms or to the husks or oil of coco-nuts from Sarawak. Dried
copra and oil of coco-nuts from the Philippine Islands are also
exempt from control.

RuBBER. The landing in the Straits Settlements of any plant
of Para rubber (including all species of Hevea) from any place
outside the Colony is prohibited, except with the written permission
of the Secretary for Agriculture, 8.8. and F. M.S.

SuGAR-CANE. The importation of sugar-cane (Saccharum offici-
narwm) from any place outside the colony is prohibited except
under the following conditions: (1) All shipments shall be con-
fined to material for planting purposes only and shall be accom-
panied by a certificate, signed by a competent authority of the
country of origin, to the effect that the said material was taken
from healthy plants and was, as far as could be ascertained at the
time of packing, free from pests. (2) All shipments of cane plants
shall be inspected on landing and before delivery by an Inspecting

239

Officer who shall be empowered to destroy any diseased plants or
packing materials, or to order their disinfection, at his discretion.
(3) All imported cane plants shall be quarantined in nurseries,
from which they shall not be removed without the written per-
mission of an Inspecting Officer.

In the Federated Malay States and Johore, the plants of which
the importation is controlled include only Para rubber and sugar-
cane and the regulations are identical in substance with those of
the Straits Settlements.

The author points out that the rules at present in force do not
ensure adequate control over the importation of plants. Cotton
and possibly other plants should be added to the list, and coco-
nuts should not be allowed free entry into the Federated Malay
States and Johore. Without unduly interfering with trade, it is
most important to safeguard valuable cultivations from the danger
of new pests introduced with commercial consignments from other
countries. The Agricultural Department is now in the habit of
requesting permission for its inspectors to examine any new plants
likely to be grown on a commercial scale in the Straits Settle-
ments or Federated Malay States, in order to ensure that the
imported plants are healthy. It is hoped to secure further improve-
ments in the present rules in the near future. .

Restrictions on import of plants and seeds into India.— Agrw.
Journ. of India, xvii, 5, pp. 511-515, 1922.

By Notification No. 580-240, dated 26th June 1922, in super-
session of that of 7th November 1917, of the Government of India
in the Department of Revenue and Agriculture, the importation
into British India of any living plant or part thereof by means of
letter or sample post is prohibited, with the exception of sugar-
‘cane for planting intended to be grown under the personal super-
vision of the Government Sugar-cane Expert, Coimbatore. AI]
plants coming by sea, other than fruits and vegetables for con-
sumption, potatoes, and sugar-cane, must be fumigated with hydro-
cyanic acid at one of the prescribed ports, namely, Bombay, Cal-
eutta, Danushkodi, Karachi, Madras, Negapatam, Rangoon, and
Tuticorin; plants infested with living parasitized insects and
intended for the introduction of such parasites are exempted from
this fumigation if accompanied by a special certificate from the
Imperial Entomologist to the Government of India. Potatoes
imported by sea must be accompanied by a certificate from the
consignor stating fully the country and district in which they were
grown and guaranteeing the absence of wart disease [Synchytriwm
endobioticum| from the farms of production, and by an official
certificate that no case of wart disease of potatoes has been known
during the twelve months preceding the date of the certificate
within five miles of the place where the potatoes were grown.
Importation of rubber plants by sea is allowed only if they are
accompanied by an official certificate that the estate from which
the plants originate or the individual plants are free from Fomes
semitostus | Ff. lignosus|, Sphuerostilbe repens, and Fusicladiwin
macrosporum | Melanopsammopsis ulei]. Sugar-cane from any
country other than the Fiji Islands, New Guinea, Australia, and

240

the Philippine Islands (from which the importation is prohibited
absolutely) may be imported by sea only if accompanied by an
official certificate that it was examined and found free from cane
borers, scale insects, aleurodes, any form of root disease, pine-apple
disease (Thielaviopsis ethaceticus), sereh, and cane gummosis, that
it was obtained from a crop free from mosaic, and that the Fiji
disease of sugar-cane does not occur in the country of export; if
the sugar-cane is imported direct by the Government Sugar-cane
Expert, Coimbatore, or by the Agricultural Chemist, United
Provinces, and intended to be grown under their personal super-
vision, such certificates shall be required only in respect of the
Fiji disease.

The importation of coffee and Hevea rubber plants and seeds by
sea from America (including the West Indies), except by the
Madras Department of Agriculture, is prohibited. Flax and
‘bersim’ (Egyptiai clover) seeds are not to be imported unless
under a licence from a Department of Agriculture in India. Cotton
seeds imported by sea must be fumigated with carbon bisulphide
at a prescribed port as above. A schedule is appended giving the
authorities in the exporting countries empowered to issue the
official certificates referred to in the Notification.

Modification of nursery stock, plant and seed quarantine.
Amendment No. 1 to regulations supplemental to notice of
quarantine No. 37 (revised).—U.S. Dept. Agric. Fed. Hort.
Board Leaflet, 2 pp., 1922.

As a result of representations made by the nursery trade, the
regulations requiring that the roots of all plants imported into the
United States should be freed from sand, soil, or earth ‘by washing’
has been modified to read ‘ by washing or other means’.

It was found that the washing of plants in the country of origin
sometimes resulted in injury, and it has been agreed that the earth
may be removed by shaking or other means in such cases.

Any importation not satisfactorily cleaned from sand, soil, or
earth by some means will be refused entry.

Prohibition of importation of Sugar-cane in Guadeloupe and
Martinique. —Agroi. Colon., vil, 57, p. 307, 1922.

A decree of the Minister for the Colonies, dated 16th August
1922, and published in a Journal officiel de la République
francaise of 24th August 1922, prohibits the entry into, and transit
across, Guadeloupe and Mar tinique of plants, cuttings, and seeds of
sugar-cane of whatsoever origin. [In the preamble it is stated
that this measure is taken chiefly because of the danger of intro-
ducing the mosaic disease of sugar-cane. |

In the interests of the colony, however, the Governor is at
liberty to authorize the importation of plants originating in
countries from which he is satisfied that there is no danger of
infection.

——————<—<— sl /? Lee CTC lhe err

—— a

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

ar PuEED. MY COLOGY

or, EL JUNE 1923

Mosaic disease of Sugar-cane.—Lowisiana Planter, |xix, 25,
pp. 442-443, 1922.

In the report of the Committee in charge of the Experiment
Station of the Hawaiian Sugar Planters’ Association for the year
ending 30th September, 1922, Lyon gives an account of the investi-
gations of mosaic disease carried on during the year by Kunkel.

The latter found mosaic on several cultivated Gramineae, including
maize, sorghum, and Sudan, Tunis, Guatemala, and Wonder Forage
grasses, and also on the common wild goose grass [ Hleusine indica }
and bristly foxtail grass [? Setaria]. Experiments resulted in the
actual transference of the disease from Sudan grass to sugar-cane
and to bristly foxtail grass, while there is strong evidence that the
disease has been transferred from sugar-cane to both maize and
sorghum. In his experiments on the transference of the disease
from one sugar-cane plant to another and from other plants to
sugar-cane, Kunkel has found only one natural agent of transmis-
sion, namely the maize aphis | Aphis maidis]|. The latter does not
feed on the sugar-cane by choice, but thrives on all the other culti-
vated grasses mentioned above. Mosaic disease in the cane fields
can therefore be greatly restricted by limiting the cultivation of
susceptible grasses in their vicinity and by the elimination of the
wild grasses liable to infection. Any measures directed against the
maize aphis should likewise tend to control the spread of the disease.
Kunkel’s experiments have also shown that the mosaic of sugar-cane
can be transmitted by inoculation from diseased to healthy plants.
Quite recently he has demonstrated the presence of foreign intra-
cellular bodies in the diseased tissues of mosaic cane similar to
those which he previously discovered in maize [see this Review, i,
p. 194], Chinese cabbage [Brassica chinensis], and Hippeastrwm.
These are believed to represent a stage in the life-history of the
agent causing the disease. In the sugar-cane they are to be found
in necrotic areas only a short distance below the growing point,
and they become obscured at an early stage in the development of

F

242

the cane tissues through the breaking down of the cells in which
they lie. They cannot, therefore, be demonstrated in the older
tissues.

In recent experiments Kunkel has found that when very young
leaves of diseased cane are exposed to bright sunlight, through the
removal of the older leaves, they develop a solid green colour and
show no signs of mosaic. Presumably the sun’s rays destroy the
causative agent. The partial recovery of old leaves when exposed
to the light is well known, and experiments to test the effect of
exposure to X-rays are in progress.

It was definitely proved by a series of experiments on four
different plantations that none of the standard canes grown in
Hawaii can produce maximum results while infected with mosaic
disease. The loss in sugar production due to this disease is very
great. The following control measures, in addition to those men-
tioned above, are recommended: the use of seed cane from healthy
plants; the destruction of diseased canes; the use of resistant
varieties where the surrounding area cannot be freed from the
disease ; the propagation of seedlings resistant to, or immune from,
the disease; and the prevention by quarantine measures of the
introduction into Hawaii of other insects likely to act as agents of
transmission.

BUREN (G. V.). Weitere Untersuchungen itiber die Entwicklungs-
geschichte und Biologie der Protomycetaceen. | urther
investigations on the life-history and biology of the Proto-
mycetaceae.|—Beitrige zur Kryptoganenflora der Schweiz,
v, 3, 94 pp., 2 pl. (1 col.), 27 figs., 1922.

This important work is divided into four sections, dealing
respectively with the forms of the genus Protomyces inhabiting
the Umbelliferae; those inhabiting the Compositae; the genus
Protomycopsis ; and the genus Volkartia.

In the species occurring on Umbelliferae, morphological observa-
tions and a series of experiments resulted in the establishment of
seven ‘formae speciales’ of Protomyces macrosporus, namely:
f{. spp. wegopodit, heraclei, chaerophylli, chaerefolit, carvi, lagustici,
and laserpitii. The ‘collective host’ for P. macrosporus is the
parsnip, Pastinuca sativa. In cross-inoculation experiments, f. sp.
aegopodit was transmitted to Caruwm, Selinum, Angelica, and
Laserpitium latifolium; £. sp. heraclei to Laserpitium latifolium
and JL. siler, and f. sp. ligustici also to L. latifoliwm. The f. sp.
laserpitii infects Peucedanum and Thapsia. Neither the col-
lective nor the secondary hosts were found to be infected under
natural conditions in the neighbourhood, presumably on account of
a deficiency of moisture in their habitat.

In the case of the Compositae, specialization is much stricter
than in the forms inhabiting the Umbelliferae. There is no record
of any form of Protomyces on a genus of the Compositae being
transferred to another genus of the same family. Only the form
occurring on Crepis bieninis (P. crepidicola) appears to have a few
secondary hosts within the genus Crepis (C. aurea and C. pontana).
The latter were very mildly attacked and infection was probably
only rendered possible by the favourable conditions prevailing

243

during the experiment. The following species of Protoiiyces
occurring on the Compositae were studied: P. pachydermus on
Taraxacum officinale; P. kreuthensis on Aposeris foetida; P.
kriegerianus n.sp. on Leontodon hispidus; P. picridis n.sp. on
Picris hieracioides; P. crepidicola u.sp. on Crepis biennis; and
P. crepidis-paludosae n. sp. on Crepis paludosa.

Various morphological differences, such as the dimensions and
colour of the spores and shape of the sporangium, characterize the
species of Protomyces parasitic on the Compositae. The only
certain means of identification, however, is the observation of
germinating chlamydospores.

The investigation of the genus Protoiiycopsis presents consider-
able difficulties owing to the, low germination percentage of the
resting spores. Four species of the genus were studied. P.
chrysanthemi n.sp. attacks Chrysanthemum alpinuny in damp
places on the mountains, causing the formation of whitish-yellow, flat
callosities, mostly on the under side of the leaves, but occasionally
also on the pedicel. The resting spores are formed terminally on
the mycelial ramifications within the leaf parenchyma, and the
vascular bundles are free from the fungus. The membrane of the
young chlamydospore is covered with small warts, and in profile
also exhibits a ring of extremely fine rod-shaped structures in the
thickness of the wall. Both these features are absent from the
mature chlamydospores, and.there is nothing to distinguish a
Protomycopsis resting spore from that of Protomyces except the
thicker membrane of the former. The diameter of the chlamydo-
spores ranges from 28-5 to 46-5 w (average 36 to 37 yw) and the pale
buff-coloured membrane is 4:5, thick. The sporangia measure
55 to 60 by about 504. Protomycopsis leucanthemi was found
capable of infecting only Chrysanthemum leucanthemum, though
the experiments were few in number. A form which is referred
to the same species was also found on C. atratum. Cross inocu-
lations showed that P. /eontodontis n.sp. is transmissible from
Leontodontis autwimnalis ( on which it was found) to J. montanus,
while P. arnoldii, collected on L. montanus, infected L. autum-
nalis, though in a very mild degree.

In 1916 the author showed (Mitt. naturforsch. Gesellsch. Bern,
pp. 112-124, 1917) that Volkartia is perennial in the underground
portions of its hosts, whence it annually renews its attacks on the
young shoots. Subsequent experiments with Volkartia wiibelli-
ferarum on Heraclewn sphondylium showed that the mycelium
also invades the floral organs; it can penetrate the pollen sacs and
cause degeneration of the pollen grains, and it also enters the ovules,
sometimes reaching the embryo sac and checking the development
of the embryo.

The author concludes by a short discussion of the systematic
position of Volkartia, in which he expresses a doubt regarding the
separation of this genus from Tuphridium. Of the two species,
V. wmbelliferarum and V. rhaetica, hitherto described, the latter
(and possibly also the former) agrees with Tuphridiwm in the mode
of spore formation, earlier accounts of the process having been
based on incorrect observations. He expresses himself as being in
entire agreement with Juel that the series of the Hemiascaceae :

244

Protomyces, Protomycopsis, and Volkartia-Taphridium, leads
directly to the Exoascaceae (Taphrina).

Mason (F. A.). Micro-organisms in the leather industries. III.
Species of the genus Penicillium and their identification
(coatd.).— Bull. Bureau of Bio-Technology (Murphy & Son,
Ltd., Sheen Lane, London), 6, pp. 161-175, 5 figs., 1922.

Of the four species of Penicillium named by the author in his
previous paper [see this Review, i, p. 44] only two, P. eapansum
and P. decumbens, are found at all frequently on leather, the last
being the more common. They belong, respectively, to the Hupent-
cillium and Aspergilloides groups, so that they can be readily
distinguished. .

P. expansum is found much more frequently on old de-natured
leather, such as worn-out boots and leather scraps, than on newly
tanned articles; in the author’s experience, skin, limed pelts, and
fancy leathers are free from it. Tan liquors contain the mould in
a small amount, and it develops slowly in tanning extracts pre-
pared from valonia and quebracho; it has not been met with in
the dust of these substances. On old leather it occurs usually in
bright blue, velvety spots up to 1 cm. in diameter, the colour being
darkest in the centre and shading off to white at the edges.

P. decumbens has been found on all kinds of leather, including
both vegetable and chrome tanned goods, on limed pelts, and on
sheepskins from the soaks. Its effect is to obliterate the grain, the
rather large, effused, indeterminate colonies spreading rapidly. Its
appearance differs with age; the first effect resembles a stain, but
later on a woolly appearance develops as the spot turns greyish-
green. Ultimately it becomes a dark green, velvety patch, without
any white boundary zone. On tanning materials the fungus occurs
frequently, having been isolated from the dust of sumach, valonia,
and quebracho; in the green scum from the tan liquors it was
found to be the dominant organism.

P. lanosum was found on leather as a secondary organism in
conjunction with Aspergillus luchuensis. 1t grows in small, grey-
green colonies, at first rather similar to those of P. expansum; but
the subsequent production of long, aerial filaments gives it a much
more woolly appearance. It was not found on tanning materials,
but grew slowly on valonia and quebracho extracts, with a darken-
ing effect on the liquid.

P. viridicatum has not been recorded on leather, but was iso-
lated by the author from a mixture of organisms collected from
a tan liquor. Growth was slow in valonia and quebracho extracts,
the liquids becoming darker in colour and a dark brown precipitate
being formed,

A table giving morphological data (from cultures on wort agar)
for the identification of the four species of Penicilliwm referred to
is appended.

FROMME (F. D.) & WINGARD (S. A.). Blackfire or angular leaf spot
of Tobacco.—Virginia Agric. Exper. Stat. Tech. Bull. 25,
43 pp., 2 col. pl., 18 figs., 1922.

The blackfire disease of tobacco caused by Bacteriwm angulatum

245

is prevalent in almost all the tobacco-growing sections of Virginia,
a survey conducted in 1920 revealing its presence in 85 per cent. of
the fields. Blackfire and wildfire (Bacteriwim tabacwm) both occur
in the seed-bed, the former being found in 70 per cent. of the beds
inspected during three seasons, and the latter in only 13 per cent.

The causal organism of blackfire is seed borne, and seedling
infection may usually be traced to the use of contaminated seed or
plant-bed cloth, on which also the pathogen may overwinter. To-
bacco refuse and, to some extent, the soil, are further sources of
infection. Raindrops are the chief means of dissemination, and
excessive rainfall also predisposes the plants to disease by inducing
a succulent and vigorous growth. The most rapid spread is during
the period of most rapid growth of the host, and the greatest injury
is caused to the most vigorous plants. The use of phosphatic ferti-
lizers indirectly promotes severe infection by increasing the size
and vigour of the plants. The difference in severity of infection
at the different heights of topping is also very marked, plants topped
at a height of eight to eleven leaves being more susceptible than
those topped at a height of twelve to fourteen leaves. These observa-
tions are believed to indicate that the pathogenicity of the organism
is closely related to the metabolism of its host. All the varieties of
tobacco grown in Virginia are susceptible to the disease, and none
of the eight tested in 1919 showed a sufficient degree of resistance
to promise effective control by varietal selection. So far no evi-
dence has been found that B. angulatum can attack any other plant
but tobacco. Seed disinfection by soaking in a 2 to 24 per cent.
formaldehyde solution for fifteen minutes or 1 in 1,000 corrosive
sublimate for ten minutes has given very satisfactory results as
regards control of the disease, but the former treatment slightly
impedes germination. As soon as the crop is harvested, the ground
should be ploughed to suppress the further growth of the plants
and prevent the accumulation of infective material.

WeBER (ANNA). Tomatsygdomme. [Tomato diseases.]—66 pp., 3 pl.
Copenhagen, N.C. Rom., 1922.

The principal diseases of tomatoes are enumerated, together with

a brief account of the symptoms, effects, and distribution of the

more important, and appropriate measures of control. The list of

diseases due to fungi, bacteria, and physiological conditions includes

.the following: Potato blight (Phytophthora infestans), foot rot
(P. cryptogea), buck-eye rot (P. terrestris) [P. parasitica], Sclerotiwm

blight (Sclerotinia sclerotiorum and Sclerotiwm rolfsii), Phoma

stem-end rot (Botrytis sp.), wilt or sleepy disease (Verticilliwm
albo-atruim), rust (Cladosporium fulvum), Macrosporiwm rot (Macro-
sporiwm tomato; M. solani), Fusarium wilt (F. lycopersici), Rhizo-
pus fruit rot (R. nigricans), and diseases caused by Pythiwm
de Baryanum, Rhizoctonia (Hypochnus) solani, R. sp., Verticillium
lycopersici, Isaria clonostachoides, Melanconium sp., Fumago vagans,
Fusariwm erubescens, F. orthoceras, F. oxysporum, F. sulphureum,
F. sp., Puccinia pittieriana, Synchytrium endobioticum, and
Spongosporu, subterranea.

246

Of bacterial diseases the following are mentioned: bacterial spot
(Bacterium exitiosum), Grand Rapids disease (Aplanobacter michi-
ganense), streak (Bacillus lathyri), and bacterial wilt (Bac. solana-
cearum).

Of the above the following have been observed in Denmark :
Phytophthora infestans, Sclerotinia sclerotiorum, Sclerotiwm rolfsii,
Diplodina lycopersici, Septoria lycopersict (not serious), Botrytis sp.
and Verticillium albo-atrum (both noticed for the first time in the
summer of 1922), Cladosporium fulvum, Macrosporium solani (of
no economie importance), Phytophthora cryptogea, Fusariun sul-
phureum, Hypochnus solani, and Bacillus lathyri. Reports of the
occurrence of Bacillus solanacearwm are probably due to a confusion
with B. lathyri.

Mosaie, leaf roll, blossom-end rot, hollow stem, cracking of unripe
fruit, and green bark, which are regarded as diseases of physiological
or unknown origin, have all been observed in Denmark. There is ~
a table for the identification and treatment of the chief diseases,
and a bibliography of 118 titles is appended.

Bapoux (H.). Ennemis du pin Weymouth. |Enemies of the
Weymouth Pine.]—Journ. forest. suisse, 1xin, 6, pp. 101-104,
1922. [Abs.in Monthly Bull. Agric. Intell. and Plant Diseases,
RIL; 7 jp. O19 922.

Jenangiwm abietis, which usually occurs on various conifers as

a simple saprophyte, has been known to cause serious, and even

fatal, damage to pines of all ages from five years upwards. Between

1914 and 1918 C. abietis attacked the white or Weymouth pine

[ Pinus strobus| in several parts of Switzerland (Ziirichberg, Horgen,

and Rothenburg), and in 1921 it occurred in a closely packed stand

of sixty-year-old pines on alluvium in the Hinterholz forest. The
diseased trees died off from the top downwards within a radius of

100 acres. The infected wood was found to be very brittle, while

the blackish discoloration rendered it unfit for commercial purposes.

Of the 587 e.m. felled in 1921 only 90 ¢.m. could be utilized in

building, &e. The stand has been thoroughly cleared to prevent

the spread of the attack.
C. abietis also occurred as a parasite in 1921 in Pomerania [see

this Review, i, p. 332].

Ranps (R. D.). Streepkanker van Kaneel, veroorzakt door
Phytophthora cinnamomi n.sp. |Stripe canker of Cinnamon
caused by Phytophthora cinnamomi n.sp.|—Meded. Inst. voor
Plantenziekten, 54, 53 pp., 6 pl. (1 col.), 1922. [English sum-
mary |.

The present paper deals with the author's recent field and labora-
tory investigations of a bark canker of cinnamon (Cinnamonun
burmanni) trees in the uplands of the west coast of Sumatra, which
for some years past has caused considerable losses. The disease is
particularly severe in badly drained inland plantations where the
trees are set far apart and interplanted with other crops. In seven
such plantations examined the estimated percentage of disease
varied from 1 to 42, and it may even reach 90 in certain cases.
Its economic importance cannot be readily assessed, since the canker

247

is frequently accompanied by insect attacks. Susceptible trees
succumb to the combined effects of the fungous and insect parasites
within a year after attack, and generally before they attain the
most profitable age for harvesting.

The most striking symptom of the disease is an irregular vertical
stripe of dead bark, 1 to 5 em. in width, originating at or below
soil level and reaching sometimes to a height of 10 to 15m. The
stripe is deeply depressed, and often bounded by callus at its base,
and is thus more conspicuous than higher up on the trunk. The
normal greyish-white colour of the bark remains unchanged, except
at the rapidly advancing upper extremity of the canker, on the
surface of which drops of an amber or wine-coloured exudate, which
soon hardens, appear. On susceptible trees the lateral growth of
an active root canker sometimes produces fresh infections, which
extend vertically close to the original stripe. On scraping off the
outer layers of the diseased bark, it will be seen that the phello-
derm, which is dark brown or red in colour, is sharply divided from
the adjacent healthy tissues by a narrow black line, irregular and
curving in the outer bark and nearly straight in the inner. The
middle and inner layers of bark exhibit, at regular intervals of
about a centimetre throughout the length of the canker, a succession
of zones (generally fifteen to twenty-five) separated by thin layers of
brown, gummed tissue. Rapidly spreading cankers were found to
extend about 1 em. daily and to develop one new zone each day. The
secretion of gum apparently begins at night. Zonation was equally
well marked under conditions in which the material differences
between day and night, as regards temperature, light, and air, were
eliminated, and also in cankers isolated from the rest of the tree.
The rhythmic spread of the fungus is, therefore, probably correlated
with some habitual periodicity in the physiological processes of the
tree,

A species of Phytophthora has been repeatedly isolated from the
margins of spreading cankers, and has invariably reproduced the
typical symptoms of the disease on inoculation into healthy trees.
It is believed to be capable of life in the soil. Two distinct strains
from widely separated localities on the west coast were compared,
and a consistent difference in their relative virulence observed.
The more virulent strain produced cankers one-third longer on an
average than the less virulent. Negative results followed the
inoculation of Hrythrina lithosperma, Theobroma cacao, Heveu
brasiliensis, and Carica papaya with pure cultures of the more
virulent strain. Conversely the species of Phytophthora occurring
on the first three of these plants failed to produce appreciable
lesions on Cinnamomum burmanni. The cinnamon Phytophthora
is thus apparently strictly limited in its parasitism and distinct
from other oriental species. On Cinnamomum zeylanicum, C.
camphora, C. culilawan, and C. sintok the inoculations resulted in
very slight infection.

The characters of the fungus in the host tissues are not described.
No fructifications were observed either in nature or in the ordinary
culture media, except chlamydospores. Conidia were, however,
obtained in profusion by the following special method. An eight to
ten-day old pea-juice culture was emptied into a sterile Petri dish,

248

the peas removed, the culture fluid drained off, and the mycelium
washed for four to six hours in three changes of sterile water. The
culture was allowed to stand in the last water for twelve to twenty-
four hours, after which the water was drained off and only enough
fresh added just to cover the mycelium. After another twenty-four
hours thousands of conidia were found on the surface. They were
of the usual Phytophthora type, except that they exhibited the
phenomenon of internal proliferation similar to that which is found
in Saprolegnia, but only known previously in a single species of
Phytophthora | P. eryptogea].

The following diagnosis of the fungus is given. Phytophthora
cinnamomi n.sp. Irregular, sparingly ramified, inter- and intra-
cellular mycelium permeating bark and outermost layers of wood :
occasional chlamydospores in the tissues; aerial hyphae on oat agar,
hyaline, slender, 5 to 7 in diameter, later thick-walled and septate ;
haustoria not observed. Chlamydospores thin-walled, globose to
pyriform, mostly 31 to 50 » in diameter (average 41 4), terminal on
short lateral branches, abundant in artificial cultures, often in grape-
like clusters of three to ten, germinating by three to eleven germ-
tubes. Conidiophores undifferentiated, simple or sympodially
branched. Conidia terminal, ovoid to ellipsoid or elongated, hyaline,
thin-walled, with a broad, flat papilla on the end opposite point of
attachment, mostly 38 to 84 by 27 to 39 (average 57 by 33);
later conidia produced on branches of the conidiophores in successive
sympodial fashion and also by internal proliferation ; wall of the
conidium partially collapsing after discharge; conidia germinate in
water by liberation of zoospores or occasionaily by a germ-tube or
the formation of secondary conidia. Zoospores bean- or kidney-
shaped, with two flagella of unequal length attached to concave
side; about 11 by 18 » while swimming and 10 to 11 yp in diameter
when at rest; germinating after about an hour by a. germ-tube.
Oospores not observed.

The control of the disease can be effected to some extent by the
prevention of wounding and the maintenance of good soil drainage.
‘These conditions are most nearly realized at present in the so-called
‘forest cultivation’, where the trees are closely planted on steep,
rocky soil, and not continually wounded by the tillage of intercrops
or by grazing stock. The trees are not susceptible to canker before
the age of two to three years, during which period intercrops may
be cultivated if desired. In the vicinity of farms or villages the
wounding of exposed roots by animals is almost inevitable, and the
planting of cinnamon trees in such localities should be discontinued.

The results of experiments in the control of the disease by excising
the diseased tissues and applying hot coal-tar, ‘ Papco’ (consisting
of asphalt dissolved in carbon disulphide), or a paraffin-soignum
solution, showed that the last-named effectually prevented further
extension of the cankers, but caused severe injuries to the cambium.
There is reason to believe that washing the wounds with a disin-
fectant before applying coal-tar or ‘Papco’ would promote the
efficacy of these preparations. For the present, simple excision of
diseased tissues, the harvesting of affected trees, and the improve-
ment of general sanitary conditions on the lines indicated above,
are recommended.

249

SUNDARARAMAN (S.). A new Ginger disease in Godavari district.
—Mem. Dept. Agric. India, Bot. Ser., xi, 9, pp. 209-217, 4 pl.
(2 col.), 1922.

During the heavy rainfall in August 1920, ginger crops in the
Godavari district, India, were attacked by a leaf disease which
spread rapidly and caused considerable damage.

The first symptom of the disease was the appearance of light
yellow, round and oval spots, 2 to 3 mm. in diameter, on both the
upper and lower surfaces of the leaves. Some of the spots
coalesced, forming large, discoloured patches with minute, black dots
in the centre, where the tissue afterwards dried up and fell out,
leaving a hole. In the final stages, minute, dark dots appeared in
irregular, concentric rings in the diseased region. These dots
consisted of the stromata of a fungus, with large clusters of hyphae
and masses of spores and setae. When the central shoots are
affected the entire surface may be studded with these dots. The
edges of affected leaves roll up and the tips bend and droop down.
In very severe cases the petioles and the scaly leaves on the
rhizomes are attacked.

The disease appears to be favoured by wind and damp, close
weather subsequent to heavy rainfall. The rain washes the spores
to lower portions of the plant, and the wind carries them from leaf
to leaf and from plant to plant. With the return of dry weather
many plants recover. The practice of close planting indirectly
favours the disease by the exclusion of light and air.

The fungus was identified as a Vermicularia for which the name
V. zingibereae n.sp. is proposed. The sporodochia are in dense
clusters, circular or oval, 50 to 140 u in diameter, and provided with
numerous erect, dark brown, septate setae, 85 to 168 yu in length.
The spores are subfusoid, curved, with blunt ends, hyaline, guttu-
late, and 17-5 to 24 by 3-1 to 4-2 4. Chlamydospores [appressoria|
of the Colletotrichum type are formed on the germ-tubes. It
differs from the species of this genus that attack chillies and
turmeric in India in the measurements of the sporodochia and the
formation of chlamydospores, but is otherwise very similar to
these forms. Cross-inoculations on chillies and turmeric gave
negative results. The parasitism of V. zingibereve was definitely
proved by repeated inoculations from pure cultures in the laboratory.
Typical disease symptoms are produced in fifteen days when the
inoculated plants are kept under humid conditions, but if kept dry
infection does not result.

Spraying with Bordeaux mixture (5—-5—50), first when the disease
was fairly distributed and again six weeks later, increased the
value of the yield by Rs 160 per acre.

Gipson (F.). Sunburn and aphid injury of Soybeans and Cow-
peas.—Arizons Agric. Exper. Stat. Tech. Bull. 2, pp. 41-46,
2 pl., 1 fig., 1922.

During the autumn of 1920 the writer observed a spotting of
the leaves of cowpeas and soy-beans near Mesa, Arizona. Investi-
gations carried out in the following spring showed the injury to be
due to sunburn and aphid attacks, succeeded by infection with a
species of Alternaria. The symptoms of sunburn and aphid injury

KF 2

250

were similar, namely the appearance of brick-red spots which
enlarged, turned brown in the centre, and later were often covered
with a sooty black growth of Alternaria. The fungus, which is
briefly described and for which the name A. atrans n. sp. is sug-
gested, was weakly parasitic, growing in needle puncture inocu-
lations in healthy plants, in leaves punctured by aphids, and in
sunburned areas.

Loss of leaves in the Virginia soy-bean is very severe, and
seriously diminishes the value of the plant for purposes of green
manure, cover, and forage. Biloxi appears tc be the most resistant
variety. The other varieties attacked were Otootan, Barchet,
Shanghai, Tokio, and Peking soy-beans and Blackeye cowpea.

Bew Ley (W. F.). Anthracnose of the Cucumber under glass.—
Journ. Min. Agric., xxix, 5, pp. 469-472 and 6, pp. 558-562,
1922.

The anthracnose of cucumbers caused by Colletotrichuim oligo-
chaetum Cay. is at the present time the most important leaf spot
disease of the cucumber in England, and is responsible for heavy
losses each year to the growers. In former years Cercospora
melonis |Corynespora melonis| caused great destruction in the Lea
Valley, but the introduction of the immune variety Butcher's
Disease Resister, in 1908, together with improved methods of soil
sterilization, led to its ultimate elimination. At present it is found
only in isolated parts of the country.

The symptoms of anthracnose are briefly described. Isolation of
the causal organism is easy, and it has been cultivated on a wide
range of artificial media. Investigations made by the author
showed that C. oligochaetwm ean live as a saprophyte on decayed
woodwork, timber, paper, and other organic matter in the glass-
house, and is thus able to tide over the winter period. A further
important source of infection has been proved to be the straw
manure from the houses and also manure coming from towns,
which is doubtless infected from diseased fruit discarded from
street stalls and the like. In no case was the fungus found in
stable manure fresh from the country.

Infected glasshouses should be cleaned by thoroughly spraying
the interior woodwork with an emulsion of cresylic acid and potash
soft soap, the formula for preparing which is given. High-power
spraying machines should be used and the ventilators must be
closed after the spraying in order to retain the strong vapours.
A fortnight after the treatment, the houses may be replanted, but
as a final precaution every cavity in the woodwork should be filled
with putty and painted over. During the growing season the
disease may be controlled by spraying the plants at weekly intervals
with solutions of liver of sulphur or lime-sulphur, to which flour
paste is added as a ‘spreader’. Four formulae for the preparation
of the spraying liquids are given and recommended as having been
tested in commercial nurseries with satisfactory results. To be
quite effective they should be used in the early stages of the disease
before the fungus has attacked the leaf-stalk and stem tissues.
On the following day after spraying every spotted leaf should be
removed and burnt. Dusting with sulphur has been extensively

251
_tested, but it has never been found to control the disease com-
pletely.
Good cultural methods and thorough (even drastic) ventilation
of the glasshouse go a long way towards preventing or controlling
the disease.

ANDERSON (P. J.). Development and pathogenesis of the Onion
smut fungus.— Mass. Agric. Exper. Stat. Tech. Bull. 4, 34 pp.,
6 figs., 1921 [1922].

Since 1918 the author has conducted an investigation of onion
smut (Urocystis cepulae), the most destructive of all onion diseases
in New England, primarily with a view to discovering effective
control measures. This necessitated an exhaustive study of the
life-history of the causal organism, the results of which are given
in the present paper.

Laboratory tests showed that mature fresh spores germinate in
onion decoction, sugar solutions, and various agars, but not in tap,
distilled, or soil water. The presence of the onion or any substance
derived therefrom is not necessary to germination, but sugar is
apparently one of the most important stimulants. Freezing does
not hasten or increase germination, but this effect is produced to
a marked degree by free access of air and also by a period of rest
in damp soil. When seedlings with unopened lesions were buried
in sterile soil, mycelium of the fungus grew out freely into the soil,
but whether it came from spores or from the vegetative hyphae in
the tissues was not ascertained. Spores frozen in the ground are
not killed. In the soil the spores become progressively prepared
for germination; a few begin to germinate in three to six days
under favourable conditions, and others germinate from time to
time for many months. This period may be shortened artificially
by the use of substances such as cane sugar.

The germination process resembles that of other species of
Urocystis. A short, hemispherical promycelium develops, and from
this arises a whorl of branches which grow indefinitely in the
form of a mycelium without bearing sporidia. Septation appears
early and the new branches generally arise below the septa. The
older cells gradually lose their protoplasm, which becomes con-
centrated in the growing tips. The cells are easily broken apart,
and detached segments, capable of further growth, are commonly
found. U. cepulae lives and grows as a saprophytic mycelium in
the soil for an indefinite period, probably for years, especially
where there is an abundant supply of organic material. It enters
the soil in the form of spores or mycelium from the buried parts of
diseased onions, and can be widely disseminated by detached
mycelial cells carried by wind, rain, implements, &c. The number
of years which must elapse before onions can safely be grown on
infested land must be decided by the duration of this saprophytic
mycelial existence, since the author has never observed sporidia
nor have spores ever been found in culture. Cultures exposed for
two months to severe winter weather still grew luxuriantly when
brought back to the laboratory.

The range of media upon which the fungus will grow is almost
unlimited. A list is given of those used by the author, together

952

~Uw

with details of the behaviour of the fungus on each, and the ©
microscopic characters of the mycelium are briefly described.
Sugar in the media was found greatly to increase development,
and is probably responsible for the rapid growth of U. cepulae in
the onion. Starch furnishes a very poor source of carbon, and a
small amount of acid checks growth. At an early stage the
mycelium disintegrates into short. plump cells which probably take
the place of sporidia as a means of dissemination.

Infection of the onion seedlings by the spores or mycelium in
the soil occurs from the second day after germination till the
appearance of the first leaf on the side of the cotyledon, namely,
a period of about twelve days in the greenhouse. Infection occurs
only through the cotyledon, any part of the epidermis of which may
serve as the point of entry, and many infections may take place on
the same cotyledon. The infecting hypha bores through the outer
wall of the epidermal cell, inside which it forms a hyphal coil from
which branches then pass through the inner wall into the inter-
cellular spaces, where they continue during the whole of their
subsequent development. Under favourable greenhouse conditions
the incubation period to the first externally visible symptoms of
infection is about five days. Large, complicated haustoria are
sometimes formed in the host cells. Infected plants may recover if
the fungus fails to reach the growing zone, but if the latter is once
invaded most, if not all, of the leaves subsequently formed will
contain lesions.

The approach of sporogenesis is first indicated by the massing of
the mycelium in dense tangles between the cells of the mesophyll.
Hyphal ‘nests’ are thus formed from which the spores develop in
sori. The spore begins as a lateral or terminal branch which
curves back on itself in the form of a crozier and may continue to
grow into a spiral. Branches arise from this curved hypha to
form a close covering around its terminal cell which becomes the
fertile central cell of the spore ball. By adhesion of the cells of
the covering hyphae and rapid expansion of the fertile cell, the
enclosing hyphae are separated into the scattered elements which
appear as the sterile covering cells of the mature spore. The
fertile cell contains a single, large nucleus, probably the result of
fusion as in allied species, though at what stage the latter occurs
was not determined ; and each sterile cell has a single, small nucleus.
As the sorus develops the host tissues above it dry out and may
split open to liberate the mature spores.

Interim Report of the Dominion Botanist for the year ending
March 31, 1922.—Dominion of Cunada Dept. of Agric.,
Divn. of Botany, 73 pp., 3 figs., 1922.

This report contains an account of the work of the Dominion
Division of Botany by H. T. Giissow, Dominion Botanist, and also
of that of the Field Laboratories of Plant Pathology at Charlotte-
town, Prince Edward Island, by J. B. McCurry, at Fredericton,
New Brunswick, by G. C. Cunningham, at St. Catherine’s, Ontario,
by W. H. Rankin, at Saskatoon and Indian Head, Saskatchewan,

by W. P. Fraser, and at Summerland, British Columbia, by H. R.
McLarty.

253

Among the items of interest the following may be mentioned.
An account is given of the outbreak of white pine blister rust
[Cronartium ribicola] in British Columbia [see this Review, i,
p. 455], where fortunately the susceptible native pines, Pinus
monticola, P. flexitis, and P. albicaulis, only form about 0-8 per
cent. of the total stand of timber. Only the coastal region has as
yet been found infected and legislative steps are being taken to
prevent further dissemination of the disease.

During 1921 the work of seed potato inspection and certification
was carried on as usual, the first inspection being made when the
plants were in bloom, and the second just before they reached
maturity. A considerable extension of territory was included in
the year’s activities, notably in Saskatchewan and Alberta. The
total area of fields inspected throughout the country comprised
nearly 8,000 acres, of which rather less than half passed the
two inspections. Thirty inspectors were employed on the work for
varying periods during the year. Full details of the standards
employed in grading the crop are given.

An important feature of the report is the detailed account of leaf
curl and mosaic of raspberries by Rankin and Hockey (pp. 30-60),
which supplements their previously published studies on these
diseases [see this Aeview, i, p. 218 and ii, p. 17.]

In a preliminary report on the strains of stem rust of wheat
(Pucecinia graminis) in Manitoba, Alberta, and Saskatchewan,
W. P. Fraser states that Strain X VII was much more common and
widely distributed during the period 1919-21 than any other. The
occurrence of Strains IIJ, 1X, XI, XIJ, and XVIII, however, was
also reported. As in previous years, the disease appeared first in
the south and later in the north. No evidence of overwintering on
grasses was obtained, the observations indicating that the spring
attack appears first on the wheat and only spreads later to the
grasses.

Experiments were carried out to test the efficacy of dusts for
the control of cereal smuts under Western Canada conditions and
to compare it with formalin treatment. Marquis wheat was shaken
in a container with spores of the stinking smuts of wheat (Z%/letia
tritict and 7’. levis). Part of the infected grain was then dusted
with anhydrous copper sulphate, with and without the addition of
calcium carbonate or lime. It was found that both copper sulphate
and lime (1—1), and copper sulphate and calcium carbonate (1-1)
reduced the amount of smut to a trace (0-65 and 0-78 per cent.
respectively), but were slightly inferior to formalin (1-320), which
completely eliminated the disease. In a similar experiment with
oats the seed was dusted with spores of Ustilago avenae. Copper
sulphate and lime, and copper sulphate and calcium carbonate
reduced the infection to 0-03 and 0-02 respectively, which again
was not quite equal to the results obtained by the use of formalin.
Copper carbonate, which has been found to be effective elsewhere,
was not available at the time of testing.

Smut of western rye grass (Agropyron tenerwm) was eftectively
controlled by the ordinary formalin treatment. The smut closely
resembles that of brome grass (Ustilago bromivora) in morpho-
logical characters. To test their biological identity, commercial

254
seed of A. tenerun was heavily dusted with spores of U. broinivora
from Bromus ciliatus but the resulting crop was no more heavily
smutted than that from the balance of “the commercial seed. This
result indicates that these smuts may be biologically distinct.

Experiments in the control of bunt of wheat by the dry formalin
method (1 part of 40 per cent. formalin to 1 part of water applied
at the rate of 1 quart to 50 bushels of grain) have been reported
frequently to result in reduction of germination. Experiments
during the period under review on Marquis wheat showed no injury
to the seed, but the treatment is not recommended on account of the
possible dangers under certain conditions.

Leaf rust of wheat (Puccinia triticina) appeared early in
Saskatchewan and Alberta in 1921, and was very severe in the
former province. In south-eastern Saskatchewan the losses from
this and stem rust are estimated at 20 per cent. of the crop.

There are numerous other records of general interest for which
the report itself must be consulted.

LisstNER (G.). Ergebnisse der Priifung neuer Mittel gegen
Peronospora, Oidium und Heu- und Sauerwurm in den Jahren
1920 und 1921. | Results of the testing of new methods for
the control of Peronosporu, Oidiwm, and Vine moth in the
years 1920 and 1921.]—Ber. hoh. staatl. Lehranst. Wein-, Obst-,
und Gartenbau zu Geisenheim-am-Rhein, 1920-21, pp. 79-85,
1929.

Excellent results were obtained by the use of \rinbalea [see this
Review, i, p. 44], a copper compound in colloidal form manufactured
by the firm of Dr. Kurt Albert at Biebrich. The copper content of
the mixture is about equal to that of Bordeaux mixture, but kurtakol
works out in practice at a cheaper rate owing to the smaller
quantities required and the absence of lime. Experiments extend-

ing over a period of five years have shown that kurtakol is quite

as effective as Bordeaux mixture against Plasmopura viticola. In

1920 only two applications were given, on 7th and 28th June

respectively, the mixture on the first occasion consisting of 500 gm.

kurtakol to 1001. water, and on the second of 660 gm. to 1001.

The vines remained healthy throughout the summer and autumn.

Comparative tests with Bordeaux mixture and nicotine gave some-

what inferior results. Kurtakol is very easily prepared for use ;

it does not clog the spraying apparatus or burn the foliage, and
may altogether be most highly recommended.

Perocid (0-5 and 1 per cent.), also prepared by Dr. Albert’s firm,
was applied on 8th and 17th June and Sth August. Plasmopara
was satisfactory controlled, but, as with Bordeaux mixture, the
autumnal discoloration of the leaves set in earlier than after the
use of kurtakol.

Nosperal 1781 and 1782 (Dyeworks, Héchst-am-Main) contain
8 per cent. copper against 24 per cent. in copper sulphate. They
are somewhat cheaper than copper sulphate (although the initial
outlay is approximately equal) on account of the smaller quantities
required, namely, 1 per cent. at the second and third applications as
compared with 1-5 and 2 per cent. of copper sulphate. The mixtures
are prepared by dissolving the powders in water and neutralizing

.

wo

a)

them on the following day with pit hme. Three applications were
given, on 7th and 24th June and 7th August, with excellent
results. Nosperal 1781 was slightly superior to 1782, chiefly in its
physiological effects, the foliage remaining exceptionally luxuriant
in colour and development.

A lye derived in large quantities as a by-product at an aniline
dyeworks had good adhesive properties but caused severe burning
of the foliage.

A preparation named ‘Kupferpasta-Bosna’, supplied by the
Bosnian Electricity Company in Vienna, gave very good results
after two 1 per cent. applications on 1lth and 24th June respec-
tively.

Oidiwim tuckert on Portuguese vines was adequately controlled
by four applications, on 5th and 24th June and 7th and 30th July,
of colloidal sulphur (3 and 6 per cent.) from Dr. Thiele’s chemical
works, Berlin. The untreated controls were very severely attacked.
In 1920 it was successfully applied in conjunction with Bordeaux
mixture for the simultaneous control of Plasmopareu and Oidiuin.

The summer of 1921 was very unfavourable for the continuation
of the experiments, Plasimopura being entirely absent on account
of the drought. The control of O/diwi with sulphur was compli-
cated by the formation of sulphuric acid on the sprayed foliage and
fruit, due to the brilliant sunshine. A new preparation from the
Héchst Dyeworks, known as ‘ Elosal’, produced very good results,
but requires further testing.

Forty-seventh Annual Report of the Ontario Agricultural College
and Experimental Farm 1921.—Ontario Dept. Agric., 55 pp.
1922.

The section of this report devoted to botany (pp. 34-39) contains
various references of phytopathological interest. Smuts and rusts
of cereals were extremely prevalent and caused heavy losses. The
damage caused by oat smut [ Usti/ago uvenue] in some of the fields
examined was estimated at 15 per cent. Leaf rust of oats [crown
rust, Puccinia lolii] was so severe that many crops were entirely
destroyed, In the eastern sections of the Province apple scab
[ Venturia inaequalis} was very severe, and the value of spraying
was again demonstrated, 80 to 95 per cent. of the fruit in thoroughly
sprayed orchards being free from the disease. Other prevalent
diseases were plum pockets [Hwouscus prvi], maize smut | Ustilugo
maydis|, stem blight of asters, and strawberry leaf scorch | Mol/isia
earliana); the latter was particularly severe in the Ontario Lake
Shore District on the varieties Glen Mary, William Belt, and
Ruby.

Investigations carried on to determine the best source from
which to obtain seed potatoes free from leaf roll and mosaic showed
that the lowest average percentage of leaf roll occurred in Green
Mountain potatoes from Northern Ontario and Maritime Provinces
stock (-5 and -6 per cent. respectively) and the highest in Irish
Cobblers from Old Ontario common stock (8-2 per cent.).

Spraying experiments in the control of late blight of celery
[Septoriu api:| have been conducted for the past nine years with
a variety of fungicides, of which only liquid Bordeaux mixture

256

has given uniformly satisfactory results. Bordeaux dust was
effectiv e, but less so than the liquid mixture.

The results of four years’ trials with dry formaldehyde for the
control of oat smut [see this Review, i, p. 486 and above, p. 254]
have proved uniformly satisfactory. In no case has chess been
more than a trace of smut in any of the fields sown with treated
seed, whereas in the control plots the average incidence of infect-
tion was 4-32 per cent. The advantages “of this method over
those in general use are simplicity, rapidity, and facility of
application.

Winter blight (also locally known as ‘streak’) is a common
disease of wreenhouse tomatoes in Ontario, and is in some eases
severe enough to interfere with the production of a profitable
winter crop. The disease also occurs in heavily manured fields.
The results of experiments conducted every year since 1914 indi-
cate that the disease is due to soil conditions and not to any
parasitic organism. Satisfactory control has been obtained by the
addition of ‘phosphoric acid and potassium to the soil.

Division of Plant Pathoisey and Physiology.—Thirty-fourth Ani.
Rept. Tewas Agric. Exper, Stat., 1921, pp. 17-19, 1921. [Reed.
1923. ]

Blossom-end rot of watermelons was found to be due to a
Diplodia which did not differ essentially from D. tubericola,
causing the so-called ‘ Java black rot ’ of sweet potatoes. Numerous
cross-inoculations of the Dzplodia isolated from the watermelon
on the sweet potato and vice versa indicated that the two strains
were identical and may readily pass from one host to the other.
The two crops should therefore not be allowed to succeed one
another. Cross-inoculations with the anthracnose fungus of
watermelons, Colletotrichum lagenarium, showed that the latter
readily infects cucumbers. cantaloupes, squashes, gourds, and
citrons. The fungus from any of these hosts is easily transmissible
to the others.

Investigations of the Texas root rot fungus, Ozoniwm omnivorum,
during 1921 tended to verify the assumption that the fungus
hibernates on susceptible roots which remain alive in the soil. The
value of crop rotation for reducing the incidence of the disease is
definitely indicated, and absolutely clean culture is essential. The
hosts of the fungus are being determined, and a full report on the
disease is in preparation.

A Fusarium from rotted stored potatoes was repeatedly isolated,
and found to cause 100 per cent. infection when inoculated into
healthy potatoes. The fungus in some respects resembled F.
oxysporum, the cause of wilt disease, but further investigations
are necessary to determine its systematic position.

It has been ascertained that the causal organism of tomato wilt
(Fusarium lycopersici) reaches every part of the pa and it was

even isolated from the fruit.

Cabbage in the Rio Grande Valley was severely attacked by
Fusarivin conglutinans, while downy mildew (Peronospora effusa)
was the chief disease of spinach observed. An apparently new and
undescribed disease, probably of bacterial origin, attacked lettuce,

257

causing a burning of the outer edges of the foliage and penetrating
into the inner leaves of the head, where it led to the development

of numerous small spots.

RusseLt (H. L:) & Morrison (F. B.). New pages in farming.
Annual Report of the Director, 1920-1921.—Wisconsin
Agric. Kxper. Stat. Bull. 339, 142 pp., 40 figs., 1922

In the section of the Bulletin devoted to plant pathology
(pp. 32-48) the following references are of interest. The investi-
gations of wheat scab and blight [Gzbberella sawhinetii| carried out
by J. G. Dickson were chiefly concerned with the temperature and
moisture relation of the disease. The results of greenhouse and
outdoor experiments both indicated that the disease is most severe
in wheat at relatively high soil temperatures (61° to 75° F.), whereas
in maize it is worst at lower temperatures (46° to 68° F.). It was
also shown that wheat flourishes best at low temperatures un-
favourable to the development of scab (46° to 53° F.), while maize
requires for its optimum growth higher temperatures than the
fungus (68° to 82° F.). A study of the influence of soil moisture
on the disease showed that in fairly dry soil, containing 30 per
cent. of the moisture-holding capacity, over 40 per cent. of the
inoculated wheat seedlings blighted at a temperature ordinarily
unfavourable to scab (46° F.), as compared with a complete absence
of blight at the same temperature where the soil moisture was 60
per cent. of the water-holding capacity. Disease-free seed at 30 per
cent. moisture made very good growth.

Field observations during the past two seasons have shown that
the scab fungus, after infecting the anthers of the wheat flowers,
develops in the adjacent tissues in the glumes surrounding the
growing kernel. The percentage of scab was found to depend on
the number of anthers remaining enclosed in the glumes. The
important commercial varieties of winter wheat, Turkey, Kharkov,
_ Kanred, Fultz, and others showed high percentages of anthers, re-
maining within the glumes, which was correlated with severe
infection. Specific attempts were made, therefore, to select indi-
vidual plants with open anthers from the varieties in which this
character was normally absent. Three strains of Turkey wheat
were obtained with the required anther formation and the resulting
plants showed only 2 or 3 per cent. of scab as against 30 to 40 per
cent. in the control plots.

Root rot of maize (G. swubinetiz, Diplodia zeae, and Fusarium
moniliforme) is a most important and dangerous disease through-
out the maize-growing section of the United States, a conservative
estimate of the total loss in 1919 being over 125,000,000 bushels,
and since that date there has been no decline in the severity of
the disease. Dry ear rot (D. zeae) is prevalent chiefly in the
warmer localities, but the wheat scab organism, as shown above, is
more destructive in the cooler sections of the maize- growing areas,
such as Wisconsin.

Owing to the dry spring and summer of 1921 the incidence of
apple scab [ Venturia inaequalis] w was so slight that the results of
a series of comparative spraying exper iments carried out by G. W.
Keitt are of doubtful significance. Bordeaux mixture (4-4-50),

a)

258

caused a serious russeting of the fruit, but a full schedule of
[liquid] lime-sulphur (1-40) and dry lime-sulphur (4-50), gave more
satisfactory results. Generally speaking, the dusts, of which
sulphur-lead arsenate (90-10), copper-lime-lead arsenate (10-80-10)
and sulphur-dry lime-sulphur-lead arsenate (75-15-10) were tested,
were slightly inferior to the sprays.

Cherry disease investigations were continued, especially with
a view to the control of leaf spot [Coccomyces hiemalis|, which was
very severe in 1921 owing to the heavy rains during the latter part
of August. Three applications of Bordeaux mixture (3-8--50), gave
the best results, the treatment being carried out (1) just after the
petals fell, (2) about a fortnight later, and (3) soon after harvest.
In general, dust treatments (with the same dusts as for apple scab)
did not give very satisfactory control. The results of the investi-
gations showed the necessity of increased attention to the control
of leaf spot after harvest.

Anthracnose of black raspberries [Gloeosporium venetwm] is
particularly severe on the Cumberland variety, and has greatly re-
duced the Wisconsin crop. The results of experiments carried on at
Madison by L. K. Jones showed that the disease could be adequately
controlled by the application of the following sprays; (1) delayed
dormant spray, lime-sulphur (1-10), or Bordeaux mixture (6—6-—50),
plus an adhesive, such as glue, gelatine, or casein-lime, after the un-
folding of the first few leaves, (2) a summer spray, lime-sulphur
(1-40), or Bordeaux mixture (8-3-50), with an adhesive, about one
week before blossoming.

Trials were carried out by W. B. Tisdale with three early
varieties of yellows-resistant cabbage, namely, Copenhagen Market,
Ball Head Early, and Glory of Enkhuizen. The first selections
were made in 1919 from ‘ cabbage sick’ fields, and in 1920 seed was
produced from a few self-pollinated plants. Plants from this seed
set in ‘sick’ soil in 1921 showed a high degree of resistance to
yellows, together with other desirable qualities. Further experi-_
ments with these strains are in progress.

J. Monteith’s studies on the relation between club root of cabbage
(Plasmodiophora brassicae) and soil temperature and humidity
showed that the disease developed through a wide range of tem-
perature (48° to 86° F.), the most active growth taking place at
about 68°F. Club root did not develop in most of the soils used
when they were maintained with a moisture content below one-
half of their water-holding capacity. At a higher moisture content
the disease appeared in a severer form. Poorly drained land, there-
fore, should not be used for cabbage culture, when club root is
prevalent.

McRae (W.). Report of the Imperial Mycologist.— Agric. Res.
Inst. Pusa, Scientific Reports 1921-22, pp. 44-50, 1922.

Piricularia oryzae, the cause of the destructive ‘blast’ of rice
in other countries, has been recorded from many parts of India,
but the damage to the crop is not usually considerable. In Madras
and Bihar fifty per cent. of the seedlings in the seed-bed may be
infected slightly, but after being transplanted the plants may ulti-

259

mately become almost free from disease. Infection experiments,
and the available meteorological records, indicate that a high
moisture content of the air and a definite temperature are the most
important factors that influence the spread and severity of the
disease. Species of Piricularia similar to that on rice have been
found on Lleusine coracana (on which it sometimes occurs in
epidemic form with a resulting loss of grain that may amount to
50 per cent.), Panicum repens (a wild grass common in the rice
‘bunds’ and water channels), Setaria italica, Paspalum sanguinale,
Triticum vulgare, and Panicum ramosum. Cross-inoculation
experiments and field observations indicate that, although the
morphological and cultural characters of the different forms are
not very distinct, their behaviour on different hosts under Pusa
conditions shows definite biological peculiarities; thus the forms on
Oryza, Panicum repens, and Paspalum are each restricted to its
own host, while those on Kleusine, Setaria, and Triticum, although
interchangeable among themselves, will not infect the first three
hosts. The strain on Panicum ramosum has been but recently
found and its behaviour has not yet been tested.

Two other diseases of rice were investigated. One of them is
due to a sclerotial fungus which has not yet been identified and
which causes light yellow-brown spots on the leaf sheath, sharply
demarcated by a dark reddish-brown line. Under favourable con-
ditions the fungus spreads over the whole plant, which is rapidly
killed. Its morphological characters, as well as the symptoms of
the disease caused by it, closely resemble those of the ‘Djamoer
Oepas’ disease of sugar-cane in Java and India; work is in pro-
gress to determine whether the fungi are identical in both cases.
The second disease, resulting in a failure of the plant to produce
grain, and recorded from Burma, Assam, and the Central Provinees,
is possibly caused by a species of Cephalosporiwm, although there
are indications that soil conditions may be the predominant factor
in determining the incidence of this fungus as a parasite.

Preliminary experiments have shown that the smut, Tolypo-
sportum penicillariae, of ‘bajra’ (Pennisetum typhoidewm) is
amenable to seed treatment with hot water (10 minutes at 60°C.)
or hot formalin vapour (20 seconds at 98°C.), though these treat-
ments slightly reduce the percentage of #ermination. The presence
of the mycelium has been traced in apparently normal grain,
occupying the scutellum and the seed coat near the embryo, thus
confirming field observations which suggest that the disease is
carried in the seed. Experiments to ascertain whether infection
takes place through the flowers indicated that this is not the ease.
Considerable annual losses are caused by the smut of this impor-
tant cereal in India and control measures on a larger scale are
being tested.

Other cereal diseases under investigation include those caused
by Fusariwm, Diplodia, and Acrotheciwm on ‘bajra’ and maize,
and by Heliminthosporiwm on rice, barley, wheat, sugar-cane, and
millets. The Helminthosporiwm work, in general, confirmed the
results previously reported [see this Review, i, p. 160].

The interesting smut Urocystis coralloides again appeared in the
same field on the roots of Indian mustard [Brassica]. The infected

260

plants are stunted and branch feebly. Attempts to germinate the
spores failed.

The study of Macrophoma corchori was continued both at Pusa
and at Dacca. This fungus causes a stem rot of jute, which is
most severe in soils deficient in potash. Applications of sodium >
sulphate appear to have a considerable influence in reducing the
incidence of this parasite. The pyenidial stage appears only on
the host plant; in artificial culture the fungus remains sterile and
produces small, black sclerotia, in which form it appears to be
identical with the organism previously described in India as
Rhizoctonia solani Kiihn [Mem. Dept. Agric. India, Bot. Ser.,
iv, 6, 1912].

McDonaLp (J.). Annual Report of the Mycological Division.—
Ann. Rept. Dept.of Agric. Kenya for the year ending 31st March,
1921, pp. 81-82, 1922.

A few diseases of minor importance were observed for the first
time. Amongst these may be mentioned ‘red mould’ of wheat,
due to the fungus Fusarium culmorum, which was reported from
the Kericho district, where its occurrence was associated with
excessive humidity. .

Ustulina zonata, which frequently attacks the roots of tea, coffee,
rubber, &c., on old forest land, caused numerous deaths among pear
and peach trees planted under similar conditions. Cases of flax
wilt (Fusarivm lini) were reported from all the principal flax-
growing centres.

Report on the Department of Agriculture, Barbados, for the
financial year, 1921-22, 19 pp., 1922.

The Director of Agriculture, Mr. J. R. Bovell, reports the occur-
rence of mosaic disease of sugar-cane, which was first observed in
a small plot in October 1920. In spite of attempts to eradicate
the disease, it spread with great rapidity and at present exists
practically all over the island.

The Assistant Director, Mr. B. A. Bourne, furnishes a report on
the entomological and mycological work of the Department.
Amongst the fungous diseases studied most attention was given to
root disease of sugar-cane,*and the results of this investigation led
to the following conclusions. Root disease occurs both on typical
black and red soils, ratoon canes being particularly susceptible. In
typical cases either Rhizoctonia solani or R. pallida was found
associated with freshly diseased and dying roots, and in advanced
stages of the disease the tissues of the basal portions of the stem
were infected by one or other of these fungi. A species of
Fusarium may also be present. Marasinius sacchari has only
been isolated from dead roots. Inoculation experiments proved
conclusively that both R. solani and R. pallida are parasitic and
capable of causing root decay and reproducing the typical symptoms
of the disease, including stunting of the plant and yellowing of the
leaves. Similar tests with M. sacchari and the Fusarvum gave
negative results. In the field the disease appears to be favoured by
a high soil temperature combined with absence of humidity. The
following control measures are recommended: planting of resistant

261

varieties and of healthy cuttings from disease-free plants; suitable
rotation of crops; proper tillage and drainage; and_ thorough
trashing of fields of young plants and ratoon canes in order to con-
serve the soil moisture and keep down the temperature.

The usual fungi, Colletotrichum falcatum and Cephalosporiwim
sacchari, associated with red rot of sugar-cane; Leptosphaeria
sacchari causing ring spot of the leaves; Thielaviopsis paradoxa
producing pineapple disease, and Cercospora vaginae responsible for
ared spot of the leaf sheath, were observed on several occasions.
The fungus associated with eye spot of sugar-cane leaves, which is
new to Barbados, was isolated in pure culture and found to agree
with the description of Helminthosporium sacchari, except in the
much greater length, often up to 75 y, of the spores. The writer
believes that Colletotrichwm faulcatum, which was frequently found
to be associated with the diseased spots, was largely responsible
for the rapid death of thedeaves subsequent to attack by H. sacchari.
Another fungus not previously recorded from Barbados was
commonly found to be associated with dead and dying cane leaves
and leaf sheaths, namely Rhizoctonia grisea (Sclerotiwm grisewm).
The writer isolated this fungus from single sclerotia from a dying
cane leaf sheath of the variety Ba. 6032.

Imphee (Andropogon sorghum saccharatus) suffered from a root
disease believed to be due to the attacks of Rhizoctonia ferrugena.
Pure cultures developed numerous reddish-brown sclerotia about
4 mm. in diameter.

A tree of lignum vitae (Guaiacum officinale) was found suffering
from what appeared to be a fungous disease. All along the stems

Phlyctaena- and Phoma-like spores.

Report on the Agricultural Department, St. Lucia, 1921. —/inyper.
Dept. Agric. W. Indies, 31 pp., 1922.

This publication contains (pp. 8-9) a copy of a report by 8. F.
Ashby, on a banana disease which has been known in the island
since 1912, and which chiefly affects the Gros Michel variety. As
a result of successful attempts to isolate the causal organism, it is
now stated that the disease is identical with the well-known
Panama disease due to Fusarium cubense. It appears to be con-
fined to the north-western districts. Attention is called to the
danger of transmitting this disease to Barbados, where it is as yet
unknown, with the banana trash that might accompany shipments
of Gros Michel fruit.

WELLES (C. G.) & RoLtpan (E. F.). Solanaceous wilt in the Philip-
pine Islands.— Philipp. Agric., x, 8, pp. 392-398, 3 pl., 1922.
Bacillus solanacearwm causes the most serious disease of tomato,
eggplant, tobacco, and other solanaceous plants in the Philippine
Islands. Young tobacco seedlings attacked by this organism show

262

a slight wilting of one or more leaves, followed within twenty-four
hours by the collapse of the entire plant, which subsequently dries
up. The stunting and more or less permanent wilting, without
killing, of larger plants is common. The annual loss varies from
5 to 15 per cent. of the crop.

Eggplant seedlings are more resistant than tobacco or tomato.
The diseased plants first show wilting of the old, outer leaves,
followed within a few days by the death of the entire plant.
In older plants the course of the disease is very gradual and
is never accompanied by total collapse owing to the support of
the woody stems, The fruits frequently become wilted and swarm
with bacteria.

Tomato seedlings, especially after transplanting, are very sus-
ceptible to this disease, total loss of the crop being common. The
older leaves wilt first, followed within twenty-four hours (or a few
days in wet weather) by the collapse of the plant. In large plants
one or two branches are first attacked, the infection rapidly
spreading over the entire growth. The fruits are also frequently
attacked.

Castor bean (Ricinus communis) exhibits similar symptoms to
those described above. No plants over 1 metre in height were
observed to be affected.

In Chrysanthemum coronariwm (apparently a new host) the
attack does not result in the collapse of the plant but kills the
green parts, leaving a tall, leafless stem. In this case the organism
has not yet been studied in sufficient detail to warrant a definite
statement concerning its identity, but it is believed to be B. solana-
cearum, though it produces a somewhat lighter pigment in culture
than that from wilted solanaceous plants.

Attempts to control the disease by applications to the soil of
copper sulphate, calcium oxide, calcium phosphate, and potassium
chloride gave negative results. The only absolute method of
control in infected soil appears to be a five years rotation of crops
in which all hosts of B. solanacearum are excluded. The eggplant,
however, may safely be planted during the rainy season, very few
losses being sustained under Philippine conditions if it reaches
maturity by the beginning of December.

MUNERATI (O.). Osservazioni sulla recettivita del Frumento per
la carie. [Notes on the susceptibility of Wheat to bunt.]|—
Rend. Acc. Inncei, xxxi, ser. 5 a, 1 sem., 3, pp. 125-129, 1922.

The author was induced to publish the present note, giving the
result of his researches in the period 1912-1917, by Heald’s paper
on the relation of the spore load to the per cent. of stinking smut
appearing in the crop [see this Review, i, p. 169].

Several series of experiments (a summary of which is given) to
test the influence on infection by Tvletia, of the soil temperature
at the time of germination of the wheat, and of the distribution of
the spores on the integuments of the grain, led the author to the
following conclusions, in agreement with those previously advanced
- by him,

The presence of even a very considerable load of Tilletia spores
on the grain is not in every case sufficient to determine the infec-

263

tion of the seedlings, the latter being much more a function of the
course and duration of the germination process of the grain.
A rapid germination gives the plant a better chance to escape
infection than a slow one. Seed disinfection, always advisable, is
therefore of particular importance when sowing has to be done late
in the autumn or early in the spring.

The theoretical probability of infection depends more on the
distribution of the spores on the.integument of the grain than on
their total number. The further the spores are localized from the
embryonal zone, the less the risk of the plants becoming infected.
If, in practice, the possibility of infection does depend to a certain
degree on the total spore load, this is due merely to the fact that
the larger the number of spores, the greater the probability that
some may find their way to the embryonal zone at germination.
If the spores remained strictly localized to the apical zones of the
grain, the seedlings would escape all possibility of auto-infection.
In this connexion the little brush of hairs found at the pointed end
of the grain, far removed from the embryo, is of considerable
importance. Under natural conditions of infection the greater
number of the spores lodge in these hairs, but they may become
distributed over the rest of the grain by rubbing or other mechanical
means. In the author’s experiments it was found that grain to
which spores were fixed by gum or paste was very heavily infected
at low temperatures when the spores were attached to the embryo-
nal zone, and lightly infected when the spores were fixed near the
apicalend. At higher temperatures the attack in both cases was
slight, but the same differences in degree were observed.

It is clear from the above considerations that, when testing
varieties or races of wheat for resistance to the fungus, or the
efficacy of a method of seed treatment, the trials should be made
under controlled conditions. In field experiments, the material
should be sown at different dates during the presumably critical
period, in order to ensure that in one series at least the host is in
a condition of maximum susceptibility to the parasite. It is also
important to ensure that an adequate amount of the infective
material reaches the embryonal zone of the grain.

SMALL (W.). Diseases of cereals in Uganda.— Dept. Agric. Uganda
Circ. 8, 19 pp., 18 figs., 1922.

In his introduction the author draws attention to the fact that
the present list of cereal diseases in Uganda is necessarily incom-
plete, owing to the very limited time available for their investiga-
tion. Several of the parasitic fungi mentioned, such as maize rust
and the red leaf spot of sorghum (Colletotrichum graminicolum),
are constantly present in varying degrees, but cause little serious
damage. Others again, such as the two wheat rusts (Puccinia
glumarwim has not yet been observed) and blast of rice (Piricularia
oryzae) consistently reduce the yield of the crop. Direct remedial
measures are impracticable in Uganda, and it is, therefore, all the
more necessary to attend strictly to general sanitary measures—the
burning of refuse, good cultivation, and the like. Scientific plant
breeding to ensure the cultivation of disease-resistant varieties is
also very desirable. The instruction of the natives in even the

264

most elementary principles of plant pathology is stated to have
proved extremely difficult, but the present account is written in
such a form as to help in the spread of information regarding the
chief cereal diseases which are described. These are as follows :—

SoraHum. Downy mildew (Sclerospora sp.), rust (Puccinia pur-
purea), red leaf spot (Colletotrichum graminicolum), leat blight
(Helminthosporium turcicwm), grain smut (Sphacelotheca sorghi),
and head smut (Ustilago reiliana).

Maize. Downy mildew (Sclerospora sp.), rust (Puccinia sorghi)
[P. maydis], and leaf blight (Helminthosporiwm turcicum).

Wueat. Black rust (Puccinia graminis), orange rust (P. triti-
cina), loose smut (Ustilago tritici), leaf spot (Leptosphaeria tritici),
mould (Cladosporiwm herbarum), and Helminthosporiwm leaf spot
(2? H. sorokinianwin).

ButrusH Mittet (Pennisetum typhoidewm). Rust (P. penniseti),
and Sphacelia disease. The latter is known from Tanganyika
Territory on Pennisetum spicatum, and is common in Uganda on
P. purpurewm as well as on the bulrush millet, but all attempts to
find its perfect stage have failed.

Crowsroot MILLET (Eleusine coracana). Leaf spot (Phyllachora
eleusines).

Rice. Blast (Piricularia oryzae).

Heap (F. D.) & SmituH (L. J.). The dusting of Wheat for bunt or
stinking smut.— Wash. Agric. Exper. Stat. Bull. 171, 28 pp.,
5 figs., 1922.

Copper carbonate, first used as a seed disinfectant by Darnell-
Smith in New South Wales in 1915, has been submitted by the
authors to a series of critical experiments designed to ascertain its
efficacy.

Preliminary experiments were carried out in the spring of 1921
on the wheats Blue Stem and Jenkins Club, the grain being
thoroughly dusted with 1 gm. of bunt [7%letia] spores to 100 gm.
of seed. The infected seed was divided into small lots, each of which
received a specified treatment, before sowing. The results showed
a relatively low percentage of bunted heads in the controls (13-6
and 3-2 respectively) owing to the weather conditions at planting,
but they also showed a perfect control by copper carbonate dust
(2 and 4 oz. per bushel) and by equal parts of finely powdered
anhydrous copper sulphate and powdered calcium carbonate used
at the rate of 2 oz. of the mixture per bushel. Copper sulphate
gave 0 and 0-4 per cent. bunted heads, and formalin 0 and 0.7
respectively. Sulphur (10 lb. and 20 lb. per bushel) gave similar
results, but is costly, and its efficacy is still open to question.
Copper sulphate reduced the percentage of germination from 84-25
and 89-5 for the untreated to 67 and 65-5; formalin to 38-5 and
53-5; whilst copper carbonate dust (4 oz. per bushel) raised it to
98-5 and 96-5 respectively.

In similar experiments started in the spring of 1922 varying
proportions of copper carbonate were used in order to ascertain the
minimum quantity necessary to give effective protection. Three
varieties were used, Marquis (resistant), Blue Stem (susceptible), and
Jenkins Club (very susceptible), and the seed was dusted with bunt

265

spores in three degrees, 0-1, 0-4, and 1-0 gm. per 100 gm. of seed.
The most heavily contaminated seed gave an average of 0-97 per
cent. bunted heads for the treated seed against 40-57 per cent. for
the controls. The following amounts of copper carbonate, 3 0z.,
1 oz., 2 oz., and 3 oz. were added per bushel and the average results
of the three varieties were 0-55, 0-09, 0-30, and 0-0 per cent. of
bunted heads respectively. A mixture of equal parts of copper
carbonate and hydrated lime used at the rate of 1 oz. and 2 oz. per
bushel yielded 0-81 and 0-76 per cent. bunted heads respectively.

Experiments were also made with anhydrous copper sulphate
mixed with equal quantities of calcium carbonate or hydrated lime.
The former mixture (1 oz., 2 oz., and 4 oz. per bushel) gave an
average of 1-15 per cent. bunted heads, and the latter (in similar
quantities) 1-65, the controls yielding 23-26 per cent. The average
for all copper carbonate tests was 0-41 per cent. bunted heads as
contrasted with 1-4 per cent. for all tests with anhydrous copper
sulphate. It seems therefore that anhydrous copper sulphate is not
equal to copper carbonate, and that hydrated lime is not so satis-
factory for mixing with the former as calcium carbonate.

A proprietary copper carbonate compound ‘Corona’ was tested
and appeared to have a better protective action than pure copper
carbonate carrying an equal amount of copper. ‘Seed-o-San’, an
organic mercury compound, was not as efficient as the copper
dusts.

In 1922 tests were carried out to show the comparative value of
various seed and soil treatments in preventing bunt originating
from wind-blown spores. Treatment was carried out with sulphur
(200 lb. per acre and 20 lb. per bushel), copper sulphate (sprinkle
of 1 lb. to 1 gall.), copper carbonate (2 oz. per bushel), anhydrous
copper sulphate with calcium carbonate (1 oz. of each per bushel),
copper sulphate (1 in 5) with or without a lime bath, and formalde-
hyde (1 in 40). All the treatments except sulphur (200 lb. per
acre) and formaldehyde were effective to some extent, but the
differences were not sufficiently pronounced to justify any con-
clusion as to the superiority of any particular treatment. A second
similar series, but with the soil artificially infected, indicated that
all the ecpper treatments brought about a reduction in the amount
of bunt.

Tests were also carried out with copper sulphate, formaldehyde,
and copper carbonate on different farms, and the latter gave the
lowest average percentage of bunted heads.

The question as to whether wheat may be dusted with copper
carbonate some months previous to seeding time without suffering
injury was tested by treating four varieties with 2 oz. copper
carbonate per bushel, ascertaining the percentage germination at
intervals, and comparing the results with those of untreated seed.
Treated seed was not injured by being kept eight months, but on
the contrary showed a higher germination than the untreated
samples. The stimulating effect of the copper carbonate treatment
is often seen in the greater vigour of growth in the fields, even in
the early spring.

On the basis of completed trials, the authors recommend the use
of at least 2 oz. of finely powdered copper carbonate per bushel,

266

but also state that 3 oz. per bushel is worthy of trial for autumn
seeded grain. The powder should test at least 50 per cent. metallic
copper, and should be fine enough to pass through a 200 mesh
sieve: the heavy copper carbonate for the metallic trades should be
avoided. Too heavy seeding after using copper carbonate should
be guarded against, as dry grain feeds faster than moist.

The wearing of some form of respirator during the treatment is
recommended, and if this is unavailable then treatment must only
be made out of doors, the apparatus being so arranged that the
wind will carry the dust away from the operator. The application
of the dust may be made in various ways, but a special dusting
machine, consisting essentially of a rotating drum, is described,
which keeps the dust enclosed while securing an even distribution .
on the grain. A blue print showing the dimensions of the machine
can be had from the Station, Pullman, Washington, for 25 cents.
Ordinary mixing by shovelling over the dusted grain is not recom-
mended, as the dust is less evenly distributed and more easily
inhaled than when shaken in a closed container.

Atwoop (W. M.). Physiological studies of effects of formaldehyde
on Wheat.— Bot. Gaz., |xxiv, 3, pp. 233-263, 12 figs., 1922.

The tests described in this paper were undertaken in order to
determine the exact nature of the effect of formaldehyde treat-
ment on the physiological processes of seeds, as shown by wheat.
Ordinary commercial formalin [termed formaldehyde throughout
by the author, as by many recent American workers] was used,
containing 39-3 parts per hundred by volume of formaldehyde gas.

In the first series of experiments the period of steeping in
formalin at the strength usually recommended (1: 320) was varied
from 5 to 300 minutes. One-third of the seeds treated were grown
in blotters in the customary manner, one-third in soil in porous
clay germinators indoors, and one-third outdoors in pots of soil
exposed to the weather and to a temperature of between 40° and
60°F. The graphs show that a dip of from 20 to 40 minutes only
slightly reduces germination, but beyond 40 minutes the descending
curves of germination are somewhat steeper, although the drop in
most cases is not great. The seeds germinated in soil showed
a somewhat greater percentage of injury than those grown in
blotters. This phenomenon has also been observed by other
workers, and an explanation of it has been suggested by Wallden
on the ground that injuries to the coleoptile, while impeding pro-
gress in the soil, need not interfere with germination of the seeds
in blotters.

In another series of tests the concentrations of formalin were
varied from 1:40 to 1: 320, and the treatment was applied for
ten minutes at 20°C. As compared with the controls there was
little injury apparent at the usual concentration of 1: 320, but with
a concentration of 1: 160, the germination curves began to fall, and
at 1: 40 the germination was reduced by 40 to 60 per cent., both in
the blotters and in the soil. As in the previous series the injury
was greatest in the outdoor soil, less in the indoor soil, and least in
the blotter tests.

267

Formaldehyde readily forms various polymers, but means for
their identification are not satisfactory. The flocculent, white pre-
cipitate which forms when the commercial solutions are concentrated
is ordinarily referred to as paraformaldehyde. If wheat is dusted
with this precipitate, serious injury results, and tests with Turkey
Red showed that germination was thereby reduced to only 9-5 to
15 per cent. The polymers persist on grain for many months, even
if exposed to the air.

In the tests designed to determine the permeability of the seed
coats to formalin, the grains were sealed one at a time to the end
of a glass tube, into which formaldehyde solution was poured.
After contact lasting three to four days, the dry tip of the grain,
exterior to the tube, was sectioned and treated directly with the
Schryver formaldehyde reagent. With long periods of exposure
to high concentrations of formalin (1:8) penetration appears to be
possible at either tip of the grain or on either face. Another
method employed by the author was to measure the degree of semi-
permeability of the seed coat indirectly by noting the weight
increase of the seeds when soaked in distilled water and in formalin
respectively, the latter in a high concentration (1:8) in order to
render more conspicuous the difference. The results of these experi-
ments lead to the conclusion that formaldehyde slowly penetrates
the seed coat, and that when the grain is subsequently transferred
to water, the formaldehyde gradually diffuses outward again.

Tests to determine the effect of formaldehyde on starch digestion
in the grain are described and illustrated by graphs. They showed
that diastatie activity is not entirely inhibited, but is retarded,
and a reduction in the amount of starch digestion was noted
corresponding with a rise in the concentration of the formaldehyde
originally used in the treatment of the seed. It would, therefore,
appear to be certain that formalin treatment lessens the availability
of carbohydrates to the germinating seedling.

Attempts to determine the effects of formalin treatment on the
amino acids of the grain failed, owing to difficulties of technique.

The elaborate respiration tests which were carried out demon-
strated that formalin has a marked influence on the respiratory
rate in concentrations of 1 : 80, the effect decreasing down to 1 : 320,
the usual concentration in seed treatment. At concentrations from
1: 400 to 1: 1000 the effect on metabolism was negligible.

The effect of formalin treatment on the catalase activity of
wheat is to depress the latter; as the concentration of the solution
is increased, catalase activity as measured by oxygen yield from
peroxides falls. The effect wears off to a certain extent with time,
and it is suggested that the injury is due more to exterior members
retaining the formaldehyde which had been in part volatilized,
than to a permanent injury to the embryo having resulted from the
treatment.

Speaking generally, the author thinks that the conclusions of
Miss Hurd [see this Review, i, p. 25] that a polymer of formalde-
hyde is deposited on dried, treated wheat, and subsequent injury
to the grain is incidental to the liberation of formaldehyde gas from
the precipitate, are in harmony with his results. But he empha~-
sizes the facts brought out in his experiments as indicating the

268

possibility of a reduction in the vitality of the seedling, even when
germination is not diminished, by formalin treatment.

Bruner (S. C.). ‘Ia muerte de los Cocoteros.’ [‘The death of
Coco-nut trees.’ ]—Rev. Agric. Com. y Trab. [Cuba], v, 1, pp.
9-10, 1922.

This is a critical review of a work by Celestino Bencomo with
the above title, published in Havana in 1921, in which coco-nut
bud rot is attributed to the activities of Oryctes rhinoceros. The
reviewer completely disagrees with this view, as according to
present knowledge no species of Oryctes exists in Cuba, and
even if one accepts Bencomo’s statement that O. rhinoceros is
synonymous with Strategus anachoreta (this, and a very similar
species, St. titanus, are not of very frequent occurrence in Cuba),
the fact remains that the writer, in examining the first phases of
the disease in situ has found no trace of these, or any other insects.

Although the writer is not convinced that a bacterium may not
cause bud rot, he states that he has never accepted as conclusive
the evidence pointing to Bacillus coli as the causative agent. The
red ring disease, which in its effects resembles bud rot, but which is
due to a nematode, Aphelenchus cocophila, probably exists in Cuba.
Phytophthora fabert Maub., which Reinking considers the cause of
bud rot in the Philippines, has been also proved by the writer to be
pathogenic to young coco-nut palms in Cuba. Ashby in Jamaica
found a similar fungus attacking coco-nuts and referred it to
Phytophthora palmivora Butl., a species which causes a very
serious disease of palms in India. According to Ashby, a similar
disease exists in the western part of Jamaica. These diseases,
which correspond closely in their characters to the disease as known
in Cuba, have al] been described since bud rot was attributed to
&. coli, and further experimental work, which the writer has in
hand, will be necessary before the true cause of death of the palms
in Cuba can be established.

BALLARD (W.8.), Macness (J. R.), & Hawkins (L. A.). Internal
browning of the Yellow Newtown Apple.—U.S. Dept. Agric.
Bull, 1104, 24 pp., 2 col. pl., 1922.

Certain varieties of apples, including Yellow Newtown, Red and
White Pearmain, Yellow Bellflower, and Missouri, grown in the
Pajaro Valley of California, where two-thirds of the apple crop of
the State are produced, are apt to develop in cold storage a brown
discoloration of the flesh, known as ‘internal browning’. The
discoloration may appear at any point in the flesh of the apple,
from the core outwards. In very mild cases a cross section reveals
only a faint brown spot in the angle between two adjacent seed
cavities. In more advanced cases the brown areas round the core
may be accompanied by discoloured patches, of varying dimensions
and intensity, in the outer flesh of the fruit. There are no external
symptoms of the disease, and it does not develop in the fruit
while on the tree or if the apples are kept at room temperatures
after picking.

Prolonged investigations have shown that internal browning is
a physiological disease, due to nutritional disturbances which affect

269

the fruit. Light crops of large, coarse-textured apples of the type
commonly produced by the cool temperature, high humidity
coupled with frequent fogs, and fertile soil of the Pajaro Valley,
are particularly liable to the trouble. In the foothills and interior
valleys, where the temperature is higher, there is more sunshine,
fewer fogs, and lower humidity, the fruit produced is so little liable
to the disease that it has no commercial importance. In seasons of
very high crop production the trouble appears to be practically
non-existent. During the years when browning was prevalent,
the fruit from trees bearing heavy crops was much less affected
than that from trees with a low yield. A light crop associated
with good leaf production is usually affected with extensive
browning in storage. Experiments showed that heavy thinning of
the fruit, combined with girdling of the branches, produced fruit
with a high sugar and acid content and a tendency to brown
severely, while partial defoliation of well-loaded branches, which
lowered the sugar and acid content of the fruit, gave sound apples.
On the whole, all the evidence obtained supports the conclusion
that browning is associated with the carbohydrate nutrition of the
tree, being most marked in trees which normally produce fruit of
rather low sugar content whenever circumstances tend to increase
that content. Heavy applications of stable manure increased the
percentage of browning, as was also the case with nitrogenous
fertilizers, except where the crop was very heavy.

Internal browning has been proved to develop most extensively
in cold storage at a temperature of 32°F. On withdrawal from
storage there is usually a marked increase in the percentage of
browning, which is therefore much more severe by the time the
fruit reaches the consumer. By maintaining the temperature of
the cold storage chambers at 36° to 38°F. the danger of internal
browning may be largely eliminated, and since 1917-1918, when
most of the apple storage houses in California were raised to
a temperature of 36°, little loss has been incurred from the disease.

OsTERWALDER (A.). Weitere Versuche zur Bekampfung des Apfel-
mehltaues. [Further experiments in the control of Apple
mildew.] Landw. Jahrb. der Schweiz, xxxvi, 6, pp. 833-834,
1922.

The author claims that apple mildew (Podosphaera lewcotrichu),
which has/proved refractory to spraying in repeated experiments
with various fungicides at Wadenswil, can be sufficiently held in
check by persistent pruning.

From a susceptible Boiken apple, 122 infected shoots were
removed in 1916, and 31 in 1917, since when the attack has been
negligible.

MUvier-TuurGau (H.). Eine durch ein Gloeosporium verursachte
Krankheit bei Cyclamenpflanzen (Cyclamen persicum). [A
disease of Cyclamen (Cyclamen persicum) plants caused by a
Gloeosporiwm.|—Landw. Jahrb. der Schweiz, xxxvi, 6, pp. 824—
826, 1922.

Nearly 30,000 cyclamen plants belonging to a large commercial
nursery-garden at Zurich were attacked by a disease which

270

resulted in the death of the young leaves and blossoms. A species
of Gloeosporiwm was isolated from the affected parts. The spore
masses were reddish in colour and the unicellular spores about 15
in length by 2-6 to 5-4 in thickness. The morphological characters
of the fungus resemble those of Glomerella rufomaculans var.
cyclaminis, which attacks cyclamens in the United States. The
symptoms of the Swiss and American diseases, however, are widely

divergent, and the causal organisms are believed by the author to

be quite distinct.

ANDERSON (H. W.). Orchard practice for the control of blister
canker of Apple trees.—TI/linois Agric. Exper. Stat. Circ. 258,
16 pp., 12-figs., 1922.

Notwithstanding the efforts of Illinois fruit growers to ex-
terminate blister canker [Vummularia discreta], the losses from
the disease have increased annually. Blister cankers occur on the
large limbs and trunks of trees, especially near large wounds ;
when old they are easily recognized by the presence of ‘ nail heads’,
the characteristic fruiting bodies of the fungus. When the bark is
worn away, the nail heads, which constitute the ascigerous stage of
the fungus, stand out about one-quarter of an inch from the wood.
On younger cankers the fruiting bodies accumulate under the bark
and cause small, blister-like protuberances, which later split open
in the form of stars. The ruptured segments curl backwards,
exposing the conidia of the fungus in a dust-coloured mass. The
inner bark of affected trees may, early in the disease, present
a characteristic mottled appearance, due to the development of
annular black lines in the tissues.

The spores of the fungus may be washed down the bark and
infect the lower parts of the tree, or may be carried to other trees,
sometimes miles distant, by birds or insects. The implements of
workmen are frequent agents of distribution. Dissemination by
air currents appears to be slight. Spores alighting on healthy
tissues or small wounds rarely cause infection, ideal conditions for
which are furnished by large, exposed wounds, such as those caused
by the sawing or breaking off of large branches The fungus
grows down into the heartwood, usually causing definite brown
streaks, and gradually becomes distributed throughout the woody
portion of the tree, even into the roots. Within a year the typical
external symptoms of the disease are visible. The conidia play
a relatively unimportant part in the distribution of the disease,
their capacity for infection being very limited. The mature nail
heads containing the active ascospores may take two or more years
to reach maturity. Young trees, under six years of age, are rarely
attacked, and no special precautions are necessary in the pruning

of the trees up to ten years old, except when they are in the

vicinity of older, cankered orchards or when the pruning tools have
_ been used on cankered trees. ’
Blister canker occurs on nearly all the commercial varieties of
apple in Illinois, Ben Davis being particularly susceptible. The
cultivation of this variety in Illinois should therefore be discon-
tinued, especially as the orchards are already overstocked with it.
Its elimination would imply an almost total eradication of the

271

disease, which on moderately susceptible varieties, such as Yellow
Transparent and Chenango, can be controlled by appropriate
sanitary measures.

One of the most important preventive measures is the immediate
dressing of wounds on the older trees with a coat of shellac and
then with a layer of gas tar. The same treatment may be applied
to areas of the bark injured by sun-scald, &c. All tools used in the
excision of cankers, pruning, or other operations, should be sterilized
with mercuric chloride (1 in 1,000) or copper sulphate. The
removal of cankers, which should be carried out in the winter,
defers the spread of the disease for several years if a good callus is
formed round the edge of the wound. The orchards should be
regularly inspected every winter and the necessary surgical
treatment, exact details of which are given, carried out. Badly
infected trees are both unsightly and unprofitable, and should be
removed and burnt. There is no danger of infection to the new
trees planted in their place.

Departmental Activities: Botany.—Jowrn. Dept.of Agric. S. Africa,
v, 4, p. 306, 1922.

Apple branch blister, caused by Coniotheciwm chomatosporum,
has been observed on a number of apple and pear twigs sent to the
Department for examination. As a rule the branches are not
seriously affected, but unless preventive measures are taken the
fungus spreads to the fruit, causing cracking and russeting. On
the twigs and branches numerous dark specks, generally in groups,
are formed, and frequently reddish-brown, irregularly raised
blisters develop. All affected twigs should be removed and
destroyed, and a winter wash (1 lb. of copper sulphate to 25
gallons of water) applied before bud-bursting time. Spraying with
Bordeaux mixture (4-450) before the flower-buds open and again
soon after the blossoms fall is recommended, and this should be
followed by a third application when the fruit is well set.

PUTTERILL (V. A.). The biology of Schizophyllum commune
Fries, with special reference to its parasitism.—Sc?. Bul.
Dept. of Agric. S. Africa, xxv, 35 pp., 5 pl, 5 figs., 1922.

The occurrence of sporophores of Schizophyllum convmune on
living apricot trees in the Cape Province, and the fact that the
wood was found to be permeated by its mycelium, led the author
to investigate the parasitism, often assumed but never experimen-
tally proved, of this fungus. He found S. commune occurring
commonly on dead wood, and also apparently as a wound parasite
on stone fruit and sometimes on apple trees. Sporophores were
generally found on parts of the tree suffering from sun-scald, but
also occurred scattered generally over quite unwounded branches.
Injuries were generally found in such cases on some other part of
the tree. The practice of slitting the hark to prevent a bark-
bound condition, and the injuries inflicted on the roots in the
process of cultivation, afford a possible means of entrance to the
fungus, but probably the most common mode of infection is through
areas in which the bark has been killed and where the healing
process is protracted indefinitely, as in sun-scald cankers. The time

272

taken by the wounds to heal and the vigour of the trees are factors
that influence infection to a certain extent, while a deficiency of
lime in the soil, such as is characteristic of the Western Province
where these observations were made, seems to increase the rate of
growth of the fungus within the host.

The diseased wood was marked by dark, radiating streaks, but,
though brittle, its hardness was not impaired and it was difficult to
cut when dry. Hyphae were abundant except in the older areas
of infection, where they seem to become disorganized and to
disappear, as is known to occur in other similar cases. The vessels,
wood fibres, and medullary rays were frequently blocked by gum,
probably formed as a result of the traumatic stimulus given by the
growing parasite to the living cells of the wood, which secrete the
gum into the fibres and vessels. In its action on the cell walls
S. commune attacks primarily the cellulose, and does not cause
delignification. Starch is absent from the cells of the invaded
tissues. The mycelium, when grown in pure culture in a liquid
medium, produced cytase, diastase, emulsin, invertase, maltase, and
lipase. It did not produce peroxidase, gum-hydrolyzing, or deligni-
fying enzymes.

The fungus was readily isolated from diseased wood, and grew
vigorously on a large number of media, the cultures being described
in detail. On media favouring growth the mycelium is at first
white and cottony, but later becomes more compact, and finally
felty, taking on a pink-buff colour; on others, as for instance potato
agar, growth is slow, there is little aerial mycelium, and the latter
is almost colourless. Sporophores, which are produced in the light
on a number of media in about 20 days, do not develop in darkness
although mycelial strands and foliar outgrowths, probably represent-
ing abortive fructifications, are formed. The hymenium faces
downwards whatever the direction of the surface of the medium,
and positive heliotropism was observed in the sporophores in one of
the experiments. In a comparison made between isolations from
a parasitic and a saprophytic strain of S. commune, the author
found sporophore formation much less marked in the latter than in
the former. Pure cultures, completely dried out, remain viable for
at least two years. Indications were found that wounding the
mycelium had a stimulating etfect on sporophore production.

Spores from a fresh spore-print germinated readily in a nutrient
solution, but very feebly in distilled water. When fresh spores
were treated with 1: 1000 copper sulphate solution for 7-5 minutes
germination was reduced by about 50 per cent., and it was almost
completely inhibited when the solution was strengthened to 1: 500.
After twelve days, spores sown in nutrient solutions gave little or
no germination, but they germinated vigorously again as soon as
copper sulphate, diluted to 1 : 5000 and 1 : 7000, was added,
germination being even better than that of fresh spores im a nutrient
medium alone.

Inoculation experiments carried out at Pretoria are fully
described. These proved that S. commune is able to grow in living
wood, which it kills, when inoculated through wounds. Of sixteen
inoculations on stone-fruit trees, twelve were successful, while four
made on the roots, green shoots, and stems of young almond trees

273

were not conclusive. In every instance the fungus was recovered
from the discoloured wood, but a sporophore was only once pro-
duced. Growth within the wood was slow under the conditions of
the experiments, reaching only about eight inches from the point of
inoculation after two years and four months. The author concludes
that though the harmful etfects of this fungus may not be immedi-
ately apparent, the total damage caused by it must be very con-
siderable owing to the insidiousness of its action and the wideness
of its distribution.

OsTERWALDER (A.). Phacidiella discolor (Mont. & Sacc.) A. Poteb.
als Faulnispilz beim Kernobst. [Piacidiella discolor (Mont.
& Sacc.) A. Poteb. as a rot-producing fungus in core fruit. ]—
Landw, Jahrb. der Schweiz, xxxvi, 6, pp. 852-853, 1922.
During the winter of 1919-20 stored apples and pears were
attacked by a black rot which diftered in various respects from that
caused by Sclerotinia fructigena. The causal organism was isolated
and identified as Phacidiella discolor, and inoculation experiments
on different varieties of apples and pears produced the typical
symptoms of the rot, which include the formation on the skin of
small, oval spots and the development of a leathery consistency in
the fruit. This is believed to be the first occasion on which the
fungus was observed on Swiss fruit.

Waters (R.). Fireblight.— New Zealand Journ. of Agric., xxiv,
6, pp. 8350-357, and xxv, 4, pp. 209-214, 9 figs., 1922.

Fireblight (Bacillus amylovorus) has spread continuously since
first reported in New Zealand [see this Review, i, p. 22], but is still
confined to the North Island. The stone fruits, mountain-ash
(Sorbus), juneberry (Amelanchier),and Pyrus japonica, all of which
are occasionally attacked in North America, have not so far shown
signs of the disease in New Zealand. Pears are the most seriously
aftected fruit trees, and with them the problem of control is more
complicated than in the case of apples. With the latter the chief
difficulty is the liability of reinfection from diseased hawthorn,
which is extensively used for hedges in fruit-growing areas. The
eradication of hawthorn from these districts is an essential factor in
the control of the disease.

The symptoms of the disease and characters of the causal organism
are described. Field experiments have shown that the effects of
blossom inoculation may not immediately be manifested, but they
become apparent in the blackening of the calyx-cup when the
young fruits begin to form. Initial infection very commonly takes
place on the blossoms, and in some districts the disease is known as
‘blossom blight’. The discoloration may extend from the immature
fruit through the stalk to the spurs or twigs, while any soft growth
is liable to infection through the punctures of sucking or biting
insects. The disease progresses more rapidly in pears than in
apples, having been known to kill large trees outright in a single
season. The young bark of apple trees is more easily penetrated
than the tougher bark of old trees.

The formation of cankers and the overwintering of the bacilli in
the so-called hold-over cankers are discussed, and it is pointed out

274

that while excision of such cankers is naturally a most important
method of control, the difficulties connected with this operation in
New Zealand appear almost insuperable, chiefly in view of the fact
that the organism has been shown to be capable of wintering over
in hawthorn cankers as well as in those of fruit trees.

Direct sunlight has been proved to have a very destructive effect
on the bacilli, which begin to succumb to the action of the rays in
less than an hour. They can withstand ordinary desiccation, as in
thin, dry films of water-diluted ooze, for about eight days. Further-
more, all strains are not equally pathogenic, and temperature has an
influence on successful infection.

On the whole, the author does not consider that the organism is
likely to possess the power of surviving in an actively infective
condition when transported over long distances by natural agencies.
On the other hand, he has found that the bacilli can live for nine
months in pure water without entirely losing their power of in-
fection. Fireblight can only have been introduced into New
Zealand, and carried over the long distances to which it has spread
within the confines of that country, by human agency. Every pre-
caution must be taken to ensure, firstly, that the disease shall not
cross Cook Strait, and, secondly, that it is confined within the
notified boundaries to infected areas. The legislative measures
taken with a view to defining the infected areas and securing treat-
ment within these areas are mentioned [see this Review, ii, p. 144],
but legislation must be supported by the co-operation of the people
if fireblight is to be prevented from reaching all parts of the
country.

The only satisfactory method of controlling fireblight is the com-
plete removal, well before the blossoming period, of all diseased
portions of the affected tree. The wounds made by cutting and
seraping should be disinfected by swabbing with a 5 per cent.
solution of formalin or lysol, or one part each of cyanide of mercury
and bichloride of mercury to 1,000 parts of water. After steriliza-
tion, the wound should be painted with a mixture of creosote and
tar, or with white lead paint, preferably the former. The steriliza-
tion of all implements in one of the above-mentioned disinfectants
is also essential.

Jackson (H. 8.). Pear blight control is feasible.—Avier. Fruit
Grower, xli, 8, pp. 3, 27, and 29, 1 fig., 1922.

The solution now most commonly recommended for the disinfee-
tion of the wounds caused by the excision of the cankers of pear
blight [ Bacillus amylovorus] is one part of corrosive sublimate and
one part of cyanide of mercury to five hundred parts of water. The
solution must not be kept in metal containers, but should be
carried in a bottle and applied with a sponge. It may also be used
for the sterilization of the tools.

It is now becoming generally known that the following varieties
of pears, in addition to the Kieffer [see this Review, 11, p. 125], are
resistant in the southern States : Garber, Tyson, Seckel, and Konnce.
The so-called Japanese seedling, Pyrus serotina, has come into
general use as a root stock, and for the same purpose the highly
resistant P. usswriensis may be used, while a very promising

‘

wo

75

Chinese species is P. calleryanu. These desirable foreign varieties,
however, are available only in limited quantities as yet and will
probably have to be grown on a larger scale in the United States.

OSTERWALDER (A.). Versuche zur Beka’mpfung de Weissfiecken-
krankheit der Birnbaume und Blattbraune der Quitten.
[Experiments in the control of white spot disease of Pear trees
and brown leaf of Quinces.|—Leandw. Jahrb. der Schiveiz,
XxXxvl, 6, pp. 839-841, 1922.

White spot disease of pear trees [Mycosphaerella sentina], which
is greatly on the increase in Switzerland and attacks a number ot
well-known commercial varieties, can be satisfactorily controlled by
two applications of 1-5 to 2 per cent. Bordeaux mixture, the first
given during the latter half of May and the second two or three
weeks later.

Similar treatment was also found effective in the control of
Entomopeziza soraueri Kleb. [Fabruea maculata (Lév.) Atk.,
Entomosporium maculatum (Lév.)], which has caused severe
damage to quinces during recent years.

CUNNINGHAM (G. H.). The significance of apothecia in the control
of brown-rot of stone-fruits.— Vew Zealand Journ. of Agric.,
Xxv, 4, pp. 225-230, 1 fig., 1922.

The apothecial stage of Sclerotinia cineres was found for the
first time in New Zealand in 1922. Between the 11th and 30th
September numerous specimens were obtained on mummied peaches
and nectarines. The trees were in blossom the whole of this period,
blossom infection first becoming noticeable on 30th September.
On 15th September plum mummies in an orchard near Christchurch
also developed apothecia. Blossom infection was observed in this
case on 29th September. Some of the mummies were those of the
preceding season’s fruit, while others appeared to be more than one
season old.

Details of the structure of the mummies and apothecia are given,
the microscopic characters of the latter being stated to agree in
most respects with the descriptions of the European form.

On 15th September ascospores were isolated and inoculated into
apple fruits, half of which were rotted at the end of ten days. No
conidia appeared on the surface until eighteen days later, the fruits
meanwhile turning dark and assuming the characteristic appearance
of brown rot.

Showery weather, accompanied by warm days and cold nights,
appears to favour the development of apothecia. Their number
decreased with the depth in the soil at which the mummies were
buried. At a depth of 3 in. only one apothecium was produced, so
that a depth of soil exceeding this amount may be regarded as
a directly inhibiting factor. All the specimens were found in hard
and compacted soil, these conditions seeming to be essential to
their production; recently cultivated soil did not yield any
apothecia.

In addition to the treatment by spraying already advised [see
this Review, ii, p. 165], the removal, during pruning operations, of
all mummies, cankered limbs, and sickly laterals, which should be

276

burnt whenever possible, is recommended, and also cultivation of
the soil after pruning but before blossoming, compacted soil being
broken by hand if necessary.

Hammonp (A. A.). Spraying experiments for brown rot of stone
fruit (Sclerotinia fructigena).—Jouwrn. Agric. Victoria, xx, 3,
pp. 182-189, 1922.

The following preparations were used against Sclerotinia
fructigena in a series of comparative experiments on plum, peach,
and cherry trees in an orchard at Seville, Australia. (1) Bordeaux
mixture used at a strength of 12-8-80 for pre-blooming, and of
3-9-50, 3-38-50, and 3-3-40 for late sprayings. (2) Woburn
Bordeaux, i.e. 13-75 galls. clear lime water, and 1 lb. bluestone,
made up to 80 galls. with fresh water. (8) Acetate of copper 1 lb.
to 13 galls. water for pre-blooming spray, and 10 oz. to 40 galls. and
15 oz. to 40 galls. for late sprays. (4) Home-boiled lime-sulphur,
26° Baumé (specific gravity 1-220), used 1 in 9 as a pre-blooming
spray. (5) Self-boiled lime-sulphur 15-15-80 used as a late spray.
(6) Sulphur sprays, including atomic sulphur, atomized sulphur,
and home-made sulphur wash (casein, skimmed milk, and flour
paste being used as spreaders in the last named). For cherries 14
galls. of lime-sulphur (26° Baumé) were added to the home-made
sulphur and skimmed milk wash, and for late spraying for peaches
1 gall. lime-sulphur was added. The home-made sulphur washes
contained 10 lb. of dry sulphur to 80 galls. water, an average of
2-75 galls. being used per tree.

None of the spray mixtures caused any injury to fruit or foliage
except Bordeaux mixture on peaches. No difference was observed
in the efficacy of any of the sulphur sprays without lime, which
have the advantage of being clean, safe, and suitable for use late in
the season. They do not, however, adhere as well as lime-sulphur,
and are therefore better adapted to hairy-skinned fruits, such as
peaches and apricots, than to cherries or plums. Bordeaux mixture
or boiled lime-sulphur may safely be used for the first spray for all
stone fruits except apricots. Cherries should receive their first
spraying when 10 per cent. of the blossoms are open, being very
susceptible during flowering to the attacks of the fungus. The
second application should be given immediately after the fruit sets.
Peaches and plums do not appear to be liable to attack during
blossoming. All kinds of fruit are apt to become infected about
ripening time, and the final applications of the sprays should be
given as late as possible consistent with clean fruit at harvesting.
Copper acetate, besides being the most expensive of the preparations
tested, was also the least effective. Exclusive of labour and fuel
the approximate cost of 80 galls. of self-boiled lime-sulphur was
3 shillings, while the same quantity of copper acetate worked out
at 7 to 9 shillings according to the strength used. Sulphur wash
and casein (home-made) cost only 1s. 10d. per 80 galls., while
atomic and atomized sulphur each cost 8s. 4d.

The writer believes that the control of the fungus by spraying
in a wet season would be extremely difficult owing to the rapidity
of fructification and spread. It should be attacked and eradicated
in dry seasons unfavourable to its development.

217

MULuLER-THuRGAv (H.). Weitere Beobachtungen iiber die
Blattbriune der Kirschbaume.—[Further observations on
leaf scorch of Cherry trees.]|—Landw. Jahrb. der Schweiz,
XXxXvi, 6, pp. 822-824, 1922.

Leaf scorch of cherry trees, caused by the fungus Gnomonia
erythrostoma, varies considerably in prevalence and intensity
according tothe locality. Generally speaking, the disease is more
severe in valleys than in elevated, sunny situations. Meteorological
conditions during the spring, however, play an important part in
the development of the fungus. The perithecia contained in the
dead leaves which remain hanging on the tree all the winter
require periodical showers for their development and for the
liberation of the spores. Hence after a dry spring there may be
only very slight infection compared with that resulting from wet
weather during the growing season.

The symptoms of the disease are also very variable, ranging
from the typical large, yellowish-brown spots to a reddish discolora-
tion. The latter occurs when the fungus penetrates the petiole
only, presumably through the glands, with the result that the
sugar cannot pass through the petiole to the branch and therefore
accumulates in the leaf. In such cases the leaves, not being directly
attacked, are able to continue their functions for a time but
gradually disturbances in metabolism arise which cannot be over-
come.

It was observed in various cases that trees which had been
severely injured in one year completeiy recovered in the next.
Atmospheric conditions not being sufficient to account for the
change, the matter was investigated with the result that Gnomonia
erythrostoma was found to be attacked by Trichotheciuim roseum,
which had completely destroyed the perithecia of the leaf scorch
organism. Experiments are in progress to ascertain whether this
valuable means of biological control can be utilized on a large scale.

OSTERWALDER (A.). Ein Versuch zur Bekampfung der durch
Pseudopeziza ribis verursachten Blattfallkrankheit der
Johannisbeerstraucher. [An experiment in the control of leaf
fall disease of Currants caused by Pseudopeziza ribis.|—
Landw. Jahrb. der Schweiz, xxxvi, 6, p. 833, 1922.

Excellent results were obtained in the treatment of this disease
in 1918 by the application of 1-5 per cent. Bordeaux mixture to
susceptible White Versailles currants. The sprayed bushes re-
mained completely healthy and green until October, in striking
contrast to the untreated controls, which lost their leaves at the
beginning of September.

MANAnREsI (A.). La ‘Sphaerotheca mors-uvae’ (Schw.) Berk.
nell’ Emilia. [Sphaerotheca mors-uvae (Schw.) Berk. in
Emilia. ]|—Riv. Patol. Veg., xii, 7-8, pp. 83-84, 1922.

American gooseberry mildew (Sphaerotheca mors-uwvae) was
first observed in Italy in 1914, when it was found in the Pavia

‘district. In 1920-21 it spread to the district of Novara and in

1922 Asti and Casale were reached. In July of the same

year the author found the fungus on gooseberry and currant

278

bushes in Emilia, where they are cultivated chiefly for jam-making
purposes. It is thought that the disease was introduced on plants
imported from other regions of Italy two years previously.
Although many bushes are affected it does not seem to cause as
much damage as elsewhere. This is believed to be due to the
energetic control measures carried out by growers, which consist
of frequent pruning, and several sprayings with lime-sulphur or
Bordeaux mixture (4 to 5 per cent.) during the resting period,

followed by the application of more dilute solutions during the.

erowing season.

OSTERWALDER (A.). Versuche zur Bekimpfung der Didymella-
krankheit an Himbeerruten mit Bordeaux- und Schwefel-
kalkbriihe. [Experiments in the control of the Didymella
disease of Raspberry canes with Bordeaux mixture and lime-
sulphur.]—Landw. Jahrb. der Schweiz, xxxvi, 6, pp. 848-849,
1922.

No satisfactory method of controlling the die-back of raspberry
canes due to Didymella applanata has yet been devised. The
results of experiments at Wadenswil with copper sulphate,
Bordeaux mixture, and lime-sulphur were all negative.

Weiss (C. O.). Diseases and pests of Raspberries.—Belter Fruit,
Xvli. 6, pp. 7-8, 1922.

This article contains notes on the principal diseases of raspberries
in the State of Washington. Crown gall [Bacterium tumefaciens],
the symptoms of which are described, 1s increasing in severity
every year, and can only be controlled by the use of absolutely
pure stock for planting. Under Quarantine No. 6 of the Washing-
ton State Department of Agriculture it is a misdemeanour to take
any plants from infected fields.

Mushroom rot (Armillaria mel/ea) causes considerable damage in
the older fields, the plants being attacked at the crown and roots.
The progress of the disease is slow, and several years may elapse
before the actual death of the plants. The rhizomorphs of the
fungus frequently grow through the soil from hill to hill along the
row. The disease is most prevalent on newly cleared land, on which
raspberries should not be planted for at least three years. Affected
bushes should be burnt and the soil where each plant stood removed
to a depth of two feet and a diameter of two to three feet. This
hole should be refilled from some other part of the field where the
disease does not occur. —

Anthracnose (Plectodiscella venetu) [Gloeosporium venetwm] has
not yet caused such serious losses in the north-western as in the
eastern districts, and may generally be controlled by cutting out the
diseased canes. In severe cases, however, spraying should be
carried out as follows: (1) before the opening of the buds, Bordeaux
mixture 5—5-50 with 1 lb. of resin fish-oil or whale-oil soap; (2) a
fortnight after flowering (when the fruit is about half grown)
Burgundy mixture (CuSO, 2 lb., Sal soda 3 lb.. water 100 gallons),
also with the addition of the soap. Stock from infected fields should
on no account be used.

Spur blight (Mycosphaerella rubina) is a common trouble on the

279

red raspberry, especially the Cuthbert and Antwerp varieties. The
first symptom is the appearance of chocolate-coloured or purplish-
brown areas on the young canes, usually just below a bud. In the
winter the affected bark turns white and becomes shredded and
loose. About mid-winter the spores of the fungus develop on the
bark, in readiness to start the new infections in the spring. The
disease may be controlled by three applications of Bordeaux mixture
2-3-50, plus 2 |b. of fish-oil soap, starting when the new shoots are
6 to 8 inches in height.

Acati (J. A.). Banana stem and fruit rot.— Philipp. Agric., x, 9,
pp. 411-422, 1922.

From 1919 to 1921 investigations of the stem and fruit rot of
bananas caused by Gloeosporiwm musarum were carried on at
the Los Bafios College of Agriculture, where some thirty varieties,
mostly foreign, were attacked. Of the native varieties the sweet
bananas were generally the most susceptible. About 15 per cent.
of the bunches were infected. The fungus was found not only on
unripe fruit but also on stored bananas, especially if the skin of the
latter was bruised or moist. The infected fruit was sour in flavour
and had a characteristic smell.

The earliest external symptom of the disease consists in the
appearance of small, black, circular specks on the skin at the distal
ends of the ‘hands’. Similar spots may also develop on the
flowers, and later on the stalk of the bunch becomes infected. The
specks become sunken and merge into one another, thus forming
larger spots, which, in severe cases, may cover the entire fruit. In
these confluent, dead areas bright red groups of spores develop, at
first moist, but later hardening and becoming dry. Infected fruits
ripen prematurely, turn black, and decay. ‘The stem becomes
stunted and dry, and the leaves droop and shrivel.

Inoculation experiments with pure cultures were conducted both
in the field and in the laboratory, 4nd showed that the fungus
readily attacked wounded fruit, but the incubation period differed
according to the variety of banana tested. In susceptible kinds it
was usually 6 to 11 days, whereas in the more resistant varieties
symptoms did not appear in some cases until after 24 days. In
needle-prick inoculations a longitudinal black streak develops from
the wound, and the surrounding areas become watery. Immature
fruits, especially when on the bunch with the inflorescences still
attached, were found to take the disease more readily than mature
fruit from which the inflorescence had fallen. , Humidity favours
infection. Natural infection may take place through the wounds
caused by cutting the bunches.

The morphological characters of the fungus are described. In
form, structure, and colour the spores corresponded closely with the
description given in text-books, but they measured 13-5 to 15.5 by
5-5 to 7-5 uw instead of 10 to 12 by 4 yw, as previously stated. There
were slight differences in the growth of the fungus on the various
media used, but the spores and mycelium produced were micro-
scopically identical in all cases. In cultures on the same medium
the organisms isolated from different varieties of banana were
indistinguishable.

280

The following precautionary measures are recommended. In the
absence of facilities for immediate transport and consumption only
resistant varieties, the names of several of which are given, should
be planted. Resistant varieties should be spaced 3 by 3 metres
apart, and susceptible varieties 4 by 4 metres. Resistant and
susceptible varieties should not be interplanted. Sweet varieties
should be planted, whenever possible, in separate fields, and the
planting of the susceptible foreign sweet varieties should be discon-
tinued. The fruit should be stored in a well ventilated room, the
susceptible and resistant varieties being kept apart. In gathering,
the rachis must not be cut close to the fruit, and the euts should be
smooth and elean. Great care must be taken not to bruise the fruit.
Ants and other insects should be kept away from the fruit, as they
may act as carriers of the spores. Spraying the fruit with Burgundy
mixture is beneficial.

Orton (W. A.) & Meter (F. C.). Diseases of Watermelons.
—U.S. Dept. Agric. Farmers’ Bull. 1277, 31 pp., 21 figs., 1922.

A brief popular account of watermelon diseases in the south-
eastern States is given, a description of the symptoms and appro-
priate measures of control being furnished in each case. Wilt
(Fusarium niveum) necessitates strict attention to cultural
measures, the most important of which is to keep infected soil free
from watermelons for a period of ten or twelve years, or even
longer. The use of organic manure should be avoided and care
taken to prevent drainage water from infected fields reaching the
crop. Resistant varieties, e. g. Conqueror, have been bred, but they
are not recommended for general use at present.

Gummy stem blight (Mycosphaerella citrullina) is increasing in
importance in the Middle West as well as in the south-eastern
States, being particularly severe under conditions of abundant rain-
fall and high temperature. There are indications that the disease
may be reduced by seed treatment, but its control has not been
adequately studied. Ground rot (Sclerotiwi rolfsii), so called
because it affects the side of the fruit next the ground, is the cause
of considerable losses in Georgia, Florida, and South Carolina. It
also attacks the roots and causes wilting and death of the whole
plant. Seed treatment and crop rotation are recommended, but the
latter is troublesome on account of the large number of hosts of the
fungus. Anthracnose (Colletotrichum lagenarium) may be con-
trolled by spraying the vines with Bordeaux mixture 4-4-50 and
hy seed treatment with 1 in 1,000 corrosive sublimate solution.

Stem-end rot (Diplodia sp.) [D. tubericola, see above, p. 256] has
caused very serious losses in transit during recent years. Thorough
field sanitation and stem-end disinfection with starch paste and
copper sulphate are the best measures of control.

Minor diseases which are occasionally encountered include leaf
spot (Macrosporiwim |Cladosporiwm]| cucumertnwm), bacterial wilt
(Lacillus trachetphilus). downy mildew (Pseudoperonospora cuben-
sis), leaf spotting due to lack of potash, and blossom-end rot caused
by the same Diplodia that produces stem-end rot, and also by other
fungi.

281

Doran (W.1L.). Laboratory studies of the toxicity of some sulphur
fungicides.— Vew Hampshire Agric. Exper. Stat. Tech. Bull.
19, pp. 3-11, 1922. [Abs. in Exper. Stat. Record, xlvii, 3,
p. 243, 1922.] 2

Investigations were conducted to determine the conditions
necessary for lime-sulphur solutions to exhibit a fungicidal action,
since these solutions have been found to vary in their toxicity to
apple scab (Ventwria inaequalis) in New Hampshire. Different
concentrations of lime-sulphur were sprayed on glass slides, allowed
to dry for 24 hours, and then conidia of V. inaequalis suspended in
distilled water were sown on the slides. On examination 24 hours
later, it was found that the lime-sulphur had not prevented the
germination of the spores.

It is stated that lime-sulphur, when dried on a tree, remains on
the sprayed surface in the form of free sulphur, calcium thio-
sulphate, calcium sulphite, calcium sulphate, and calcium carbonate.
The toxicity of calcium sulphate, calcium sulphite, sulphur, and
precipitated sulphur was tested, and it was found that calcium
polysulphide decomposed most rapidly and decreased in fungicidal
efficiency when dried slowly. Sulphur was toxic only in the
presence of oxygen, and its toxicity increased with rise of tempera-
ture and length of exposure. Precipitated sulphur proved more
toxic to the conidia of V. inaequalis than finely ground sulphur,
and acted at lower temperatures. Fungi were found to vary in
their susceptibility to the toxic action of the sulphur.

Zur Saatgutbeizung. [On the disinfection of seed.|—Nachrichtent/.
deutsch. Phanzenschutzdienst, 11, 10, p. 88, 1922.

According to a statement issued on September 13, 1922, by the
Bavarian Ministry of Agriculture, the winter rye seed sown last
autumn was attacked in an unusually severe degree by Fusarium.
Samples examined by the National Institute for the Cultivation and
Protection of Plants at Munich showed 80 to 90 per cent. of in-
fection. The following fungicides are recommended for rye seed
disinfections: fusariol (Fikentscher, Marktredwitz, Bavaria), ger-
misan (Saccharinfabrik, Magdeburg), and uspulun (F. Bayer & Co.,
Leverkusen).

Kasat (M.). Ueber den auf der Binse parasitisch lebenden Pilz
Cercosporina juncicola sp.n. [The fungus Cercosporina juici-
cola sp. n. eee ig? the Rush.|—Ber. Ohara Inst. landw.
Forschungen, ii, 2, pp. 225-231, 3 pl. (1 col.), 1922.

The rush Juncus effusus var. decipiens, which is extensively
cultivated in Japan for the manufacture of mats, has been attacked
for at least the last twenty years by a stem spot disease. In the
summer of 1921 the author visited one of the principal affected
localities (Bingo, in the province of Hiroshima), and also examined
a number of diseased specimens submitted to him. In the following
summer the causal organism, which was constantly present on the
affected stems, was identified as a species of Cercosporina.

The author states that the only allied fungus known on the rush
is Cercospora juncinu Sace. from Ontario, but the species discussed
in the present paper differs from this in the symptoms of the

282

disease which it causes, as well as in the structure of the conidio-
phores, dimensions of the conidia, &c. About twenty years ago,
Hori found frucetifications of a Cercospora on diseased rushes in
Japan and proposed to name the fungus C. juncz. This, however,
he did not do, and as it is highly probable that Hori’s fungus was
identical with the present one, the author names the latter Cerco-
sporina jwneicola Hori & Kasai sp. n.

The disease, which is confined to half-grown plants, does not
appreciably disturb their metabolism, since the mycelium does not
extend far from the point of infection, and large portions of the
stem, between the spots, remain quite green and healthy. Affected
stems continue to grow without bending, and are normal in appear-
ance except for the spots. The damage caused by the disease is
noticeable chiefly in the finished product. The mats woven from
diseased rushes are spotted and unsightly, and this greatly detracts
from their commercial value. ,

The spots are irregularly distributed over the middle portion of
the stem. At first they are extremely minute and invisible to the
naked eye, but later they increase in size and become somewhat
depressed owing to shrinkage of the affected tissues. They are
very variable in shape, often confluent, whitish to ashy-grey in the
centre, and surrounded by a dark-red or brown edge. ‘The central
portion, on which the conidiophores are borne, may measure up to
about 7 by 3 mm.

The mycelium is ordinarily hyaline and profusely septate, but in
places the hyphae often swell into brown, vesicular cells or groups
of cells. This appears to represent a perennial mycelium, and
a similar development is also found in pure cultures on rush
decoction.

The conidiophores may be observed on almost all diseased plants.
They are yellowish-grey in colour, and emerge from the stomata in
expanding clusters. They are sometimes elongated, measuring 10
to 28 by 4 to 5 w, somewhat thickened at the base, generally 1- or
2-, and occasionally 3-septate; and sometimes short and bulbous,
only 4 to 6 by 4, and non-septate. In very moist air much
longer conidiophores, with numerous septa, are formed; the
separate segments in this case often break off and resemble spores.

The conidia of the fungus, which are sparsely developed, and are
extremely difficult to detect on dried specimens, are borne partly
on the apex of the conidiophores and partly on sub-apical lateral
protuberances. At first they are narrow, clavate, and non-septate,
but later they become pointed and 3-septate, and are somewhat
thickened at the basal end, where a button-shaped, rudimentary
‘foot’ also occurs. They are hyaline, or occasionally very pale
green, and measure 23 to 48 by 2 to 3y. The length may increase
to two or three times the normal in a humid atmosphere, but the
breadth remains unaltered. They are very easily detached from the
conidiophores, and germinate in a few hours in water. The germ-
tubes penetrate through the stomata.

The best means of controlling the disease is to collect and burn
all infected material at harvest time, and to use only healthy cut-
tings for propagation. If the cuttings have been exposed to
infection, the stalks (but not the roots) may be immersed for a few
minutes in Bordeaux mixture.

283

Ricerche e studi compiuti o in corso presso la R. Stazione di
Patologia vegetale. [Research work and studies, completed
or in progress, at the Royal Station of Plant Pathology.|—Bo//.
mensile R. Staz. Pat. veg., ii, 10-12, pp. 120-124, 1922.

A brief account is given of further work by Peyronel on
mycorrhiza. He has extended his investigations from cereals to
a large number of cultivated and wild plants, particularly her-
baceous ones ; no list of these is given, however. He finds that in
nearly all mycorrhiza-bearing roots two distinct mycelia are to be
found, at least in the epidermal region. One of these resembles in
its morphological characters some of the Phycomycetes, and is, he
thinks, the more important of the two, judging from its develop-
ment and behaviour in the radical tissues, but it has so far not been
possible to grow it in culture. The other is a Rhizoctonia which
he considers probably identical with Rhizoctonia solani, and
perhaps also with a fungus which seems widespread in northern
countries, especially Germany, where it is supposed to damage
garden plants, and which is known by the name of ‘ Vermeh-
rungspilz’ (Moniliopsis aderholdi Ruhland). The Rhizoctonia in
question has been isolated from many plants and grown in culture.
On potato tubers it resembles typical Rhizoctonia solani ; im culture
its behaviour is the same as that of the endophytes of orchid roots,
and like these it produces a quantity of Monilia-like conidia, such
as described by Petri on the mycorrhizal mycelium of the vine and
olive. Asterocystis radicis was found frequently on the roots of
a number of herbaceous plants.

Besides these fungi, which Peyronel regards as probably truly
mycorrhizal, inasmuch as no pathological effects are produced by
their growth in the roots, several others were nearly always met
with, especially in the older root-hairs and epidermis some distance
from the growing apex. Particular mention is made of a Fusarium,
a Hyphomycete not yet determined resembling Didyimopsis
omnivora, and a Pythium. Though probably only semi-parasitic,
it is possible that these fungi may under favourable conditions
penetrate into deeper tissues and do some damage.

From observations in the valleys of Piedmont, Peyronel considers
that some ectotrophic mycorrhiza of trees, such as that found on
Larix decidua, are represented by a Rhizoctonia identical with, or
similar to the one already discussed. On Alnus wiridis he has also
found an ectotrophie mycorrhiza in addition to the characteristic
tubercles. These he proposes to discuss in a future paper.

DEMAREE (J. B.). Kernel spot of the Pecan and its cause.—
US. Dept. Agric. Bull., 1102, 15 pp., 5 figs., 1922.

The kernel spot of pecan, a common disease in the southern
States, was attributed by Rands to Coniothyrium caryogenum, and
by Turner to insect punctures. The author carried on a series of
experiments with two varieties of pecan encased in wire cages, in
which the effect of southern stinkbugs (Nezara viridula) on the
nuts was determined. The results of the tests led him to the con-
clusion that the pecan kernel spot is due to the action of the insect
in mechanically rupturing the host cells, sucking the plant juices,
injecting toxie substances into the tissues, or all three types of
injury combined,

284

HAsENOHRL (R.) &~ ZELLNER (J.). Chemische Beziehungen
zwischen den héheren Pilzen und ihren Substraten. [Chemical
relations between the higher fungi and their substrata.|—
Monatshefte fiir Chenvie, xiii, pp. 21-41, 1922.

The water content of a fungus is generally higher than that of
its host. K and PO, are the principal mineral constituents, Ca
low, Na very low, except possibly in some coprophilous fungi, and
Fe always present, though sometimes in very small quantities.
The constitution of the substratum does not influence the com-
position of the ash in fleshy fungi. New ash analyses are given of
the following: Polystictus microloma, Polyporus fomentarius,
P. borealis, and Auricularia mesenterica. In these K is lower and
Ca higher than in fleshy forms. In Tramnvietes suaveolens, Polyporus
igniarius, and P. fomentarius CaSO, is specially high, while
Polystictus microlomea is very rich in NaCl.

A number of experiments were conducted to compare the osmotic
pressure in different fungi and their hosts, and in almost every
case the osmotic pressure of each soluble constituent present was
higher in the fungus than in the host.

Experiments carried out with a view to detecting cellulose- or
lignin-splitting enzymes in Polyporus igniarius, P. hirsutus,
Trametes suaveolens, Lenzites saepiaria, and Armillaria mellea
gave negative results. Analyses were made of a specimen of oak
on which P. igniarius had been parasitic. The tree had lost 74
per cent. of its weight and the whole of its starch, sugar, and
tannin. Otherwise its composition did not differ in the relative
proportions of the different constituents of the cell membranes, &c.,
from that of the healthy oak, showing that the material of the oak
was taken up equally by the fungus, without selective attack on
any particular substance.

KENTISH WriGHT (O.). The action of yeast-growth stimulant.—
Biochem. Journ., Xvi, 1, pp. 187-142, 1922.

Wildiers’ observation that certain yeasts can only grow at the
expense of ammonium salts provided a heavy inoculation is em-
ployed, or a small quantity of organic material (‘bios’) added to
the medium, has been confirmed by. Williams and Bachman [1919].
These authors suggest that ‘bios’ is identical with the water-
soluble B or anti -beri- beri vitamin, but the case for the identity of
the two principles is not generally regarded as proven.

Lemon juice freed from citric acid added to a mineral nutrient
solution in small quantities enables a yeast to grow which could
not develop in itsabsence. The amount of water-soluble B vitamin
in lemon juice being very small compared with that in yeast_
extract, an investigation was undertaken to ascertain its effects on
the growth of yeast in mineral nutrient solutions.

A series of tubes was prepared containing the following solution
with increasing percentages of lemon juice: saccharose, 20 gm.;
(NH,),SO,,3 gm.; KH,PO,,2 gm. ; CaCl,,0-25 gm. ; MgSO,, 0-25 gm.;
and distilled water 1 000 ce. A similar series of tubes was prepared
omitting the (NH,) ),80,. The yeast employed was a pure culture
of a baker's yeast. It was found that no growth took place in the
mineral nutrient solution unless 5 per cent. or more of lemon juice

285

was added. The rate of growth was more or less directly pro-
portional to the amount of lemon juice used, up to about 15 per
cent. After the yeast reached a concentration of five or six million
cells per cc. it was able to continue growing freely in the
(NH,),SO, tubes without the appearance of involution forms and
with no film formation, When the concentration had not reached
this point after six days, involution forms began to appear in the
(NH,),SO, tubes and by the ninth day a heavy film was produced.
Apparently after six or seven days the cells in smaller concentra-
tions than five or six million per cc. are able to adapt themselves
to the use of (NH,),SO, but only so that film formation results.

Another series of tubes was prepared with increasing percentages
of aqueous yeast extract instead of lemon juice. It was found that
the yeast extract was about ten times as effective as Jemon juice in
promoting growth, although its nitrogen content is more than
thirty times as great. The yeast experiment confirmed the previous
one in showing that the rate of growth is independent of the
presence of (NH,),SO, during the early period of the cultures and
depends on the concentration of the ‘bios’ until the yeast has
reached a concentration of about five or six million cells per cc.,
after which it proceeds further in the presence of (NH,),SQ,.

Before proceeding to investigate the general question of vitamins
by studying the biological processes in a yeast on these lines, it is
necessary to be satisfied that ‘bios’ is actually a vitamin. The
present investigation, however, suggests that ‘ bios’ does not enable
the yeast to assimilate (NH,),SO, simply by its presence, or by
being consumed simultaneously, but merely that the yeast grows
solely at the expense of the ‘bios’ until it reaches a certain degree
of concentration, after which it is able to use the (NH,),SO,.

ATANASOFF (D.). Stipple-streak disease of Potato.—Meded.
Landbouwhoogeschool, Wageningen, xxiv, 5, 32 pp., 5 pl. 1922. °
| Dutch summary. |

Stipple-streak disease of potatoes, which occurred very severely
in Holland in 1921, especially on the early variety Schotsche Muis

(Victory), is allied to the degeneration or ‘running out’ group of

diseases, which includes leaf roll, mosaic, and crinkle. The distribu-

tion of the disease is very general in Western Europe and North

America, and a number of important commercial varieties are

affected, including Green Mountain, Ninetyfold, President, Ashleaf,

and Irish Cobbler. In the author’s opinion, detailed grounds for
which are given in a separate publication [‘ A study into the literature
on stipple-streak and related diseases of potato. —Meded. Land-
bowwhoogeschool, Wageningen, xxvi, 1, 1922], the older references
to potato ‘ leaf curl’, ‘Krul-’ or ‘ Kroesziekte’, ‘ Krause-’ or ‘ Kriusel-
krankheit’, ‘ Frisolée ’, and ‘ Pirve’ in various European countries,
all mean the disease described in the present paper, whereas of
recent years these names have been indiscriminately applied to
other diseases such as leaf roll, mosaic, and the like. With stipple-
streak the author also identifies Sorauer’s ‘ Stippelfleckenkrankheit’,

Horne’s ‘ Leaf blotch’, Miss Dale’s ‘ Blindness’, Orton’s ‘ Streak’,

Appel’s ‘Schwarzflecken- und Streifenkrankheit ’, Giissow’s ‘ Leaf-

streak’, and Murphy’s ‘ Leaf drop’, while Appel’s Bakterienring-

286

krankheit was a combination of this and a bacterial soft rot of the
tubers. The Dutch name ‘Stippel-streepziekte’ was first suggested
by Quanjer, and the author advocates the use of this name in
Dutch, of ‘Streak’ or ‘ Stipple-streak’ in English, and of ‘ Schwarz-
flecken- und Streifenkrankheit ’in German. He thinks the French
may accept the English name.

During the 1921 epidemic in Holland a few of the potato crops
were affected to the extent of 75 per cent., while 20 per cent. of
infection was fairly common. In its primary form, stipple-streak
is an easily recognizable disease, but secondary stipple-streak plants,
i.e. those that arise from the tubers of primarily diseased plants, are
often almost indistinguishable from those infected with crinkle or
mosaic.

The first symptom of primary stipple-streak, which is most —
marked on early, succulent, and light green varieties, is the develop-
ment of dark brown spots between the veins of the lower or middle
leaves of the plant. The spots have a distinctly angular outline,
the number of angles varying from three to five (usually the latter)
or more. The spots are generally less than 0-5 em. in diameter,
uniform in colour and texture, and slightly depressed. In warm
weather this preliminary symptom is succeeded by the appearance
of black spots near the veins of the young leaves, just below the
growing point. These spots are elongated, small, and very
numerous. At this stage there is already a suggestion of mottling,
and the affected plants somewhat resemble those attacked by
mosaic disease. Dark, olivaceous-green to brown stripes are found
on one or more sides of the stem. Sometimes the affected side of
the stem and the spotted leaves on it are completely destroyed,
while the opposite side continues to grow, causing a bending of the
whole shoot to the diseased side. ‘These stripes represent groups
of dead or severely diseased cells and tissues, beneath the still
normal epidermis and sub-epidermal layer. Their borders are not
clearly defined and they have a water soaked appearance. Both
stems and leaves begin to wilt from the top downwards. The
disease usually spreads to all the shoots within two or three weeks,
killing the plant. The first cases in Holland were observed in
May, but the disease continued to appear throughout the growing
season.

Affected tubers._show on the surface distinct, slightly elevated
blisters on and near the eyes and at the stem end. The blisters
soon shrink and leave only dark brown or cinnamon-coloured spots.
When they appear on young tubers, the cork layer and cortex split
in various directions. The tubers of infected plants, even those
which appear quite. healthy at harvest time, may become blistered
and discoloured in storage. Internally affected tubers can be
recognized by their uneven and granular surface and by the deep-
lying, brown blotches visible through the periderm. Sometimes
the eyes of the tubers are completely and permanently destroyed.

When infected tubers are planted out they either fail to develop
or produce stunted plants with small, crinkled leaves and short
petioles. This is the secondary type of the disease. The leaves
are slightly mottled and show the typical symptoms of stipple-streak
described above, the brown spots, however, being less numerous

287

than in the primary form. The stems are covered with brown
stripes and are split crosswise. The whole plant is extremely
brittle, and the lower leaves fall, till at length only a few are left
at the top. The plants generally die during the first month after
their appearance. New sprouts may be formed once or twice after
this, but they pass through the same phases as the first ones. The
seed tuber usually persists without rotting, and one or more small,
new tubers, discoloured and covered with blisters and splits, may
also be found. They seldom sprout if planted, and when they do
it is only to produce diseased ‘shoots which die without bearing
tubers.

In its secondary form stipple-streak differs from mosaic, crinkle.
and leaf roll mainly in its severity, accomplishing in two or at most
three generations from the first attack what the others achieve
after a much longer period. It most closely resembles crinkle, but
can usually be distinguished by a careful comparison of the
symptoms, the differences being set out by the author in tabular
form. It is also rather like a still undescribed disease, for which
Quanjer has proposed the name leaf-drop-streak, except that there
is no spotting of the leaves in the latter. Like other ‘running-out’
diseases, stipple-streak is systemic, spreading into all the shoots
produced by the same tuber.

The pathogen of the disease, no suggestions regarding the nature
of which are given, does not leave the plant under ordinary con-
ditions and very likely dies with it. Healthy Schotsche Muis
tubers stored in a damp cellar with 95 per cent. of heavily infected
tubers of the same variety gave absolutely healthy plants. In
another case healthy and diseased tubers were planted side by side
in the same pot, with the result that the former gave healthy
plants and the latter diseased ones. These and other experiments
prove conclusively that the pathogen cannot pass from plant to
plant through the soil, water, or air. Attempts to infect healthy
plants with the sap from diseased ones also gave negative results. By
establishing an organic connexion between a healthy and a diseased
plant, however, it was possible to transmit the infection. This was
done in two ways: by joining the cut surface of healthy tubers with
that of infected ones so that an organic union was formed, and by
grafting infected plants on healthy ones. In this respect also
stipple-streak resembles leaf-roll, mosaic, and crinkle. Field
observations indicate that natural spread of the disease from plant
to plant occurs, but the manner of this is not known though insect
transmission is evidently suspected. Temperature has a marked
effect on the appearance and development of stipple-streak.
Experiments showed that a temperature between 5° and 10°C.
retarded the development of the disease and enabled the plants to
make a normal growth without, however, destroying the source of
infection, as the disease reappeared when they were again placed
in a hot-house. Higher temperatures accelerated the progress of
the infection.

Experiments in the treatment of infected tubers with 2 per
cent. copper sulphate for one and two hours and 2 per cent.
mercuric chloride for half an hour and one hour gave absolutely
negative results. Tubers heated in dry air at a temperature of 44°

288

to 46°C. for 5, 15, and 24 hours also gave secondary stipple-streak
plants in all cases. It is evidently impossible to destroy the
pathogen of stipple-streak in the tubers without injuring the
latter. It seems highly probable, however, that the disease can be
controlled by the elimination of infected tubers and young plants,
and this can be much more readily effected than in the case of the
other running-out diseases, since the yield of tubers from infected
plants is negligible in the second generation from infection.

Dvuspoys. Ia lutte contre la ‘ dégénérescence’ des Pommes de
terre dans l’Ouest de la France. [The campaign against
‘degeneration’ of Potatoes in the west of France.]—Rev. de
Bot. appliquée, ii, 14, pp. 586-589, 1922.

None of the potato varieties cultivated in Brittany, the chief
centre of seed potato cultivation in France, is immune from leat
roll and mosaic, though the early varieties grown along the coast
appear to be relatively less subject to these diseases. The selected
early varieties Fluke (Géante de St.-Malo) and Fin-de-Siecle (Up-to
Date) show a very low percentage of attack, apparently on account
of the scrupulous care on the part of the local growers in the
choice of their seed. Any plants deviating at all from the normal
type in stature, shape of the leaves, colour of the flowers, and the
like, are discarded. The practice of ‘greening’ and sprouting in
trays exposed to air and light has also the advantage of enabling
the growers to discard any seed tubers with abnormal (spindly)
sprouts.

Unfortunately the late-maturing varieties grown inland do not
receive the same attention, and the yield obtained from them is
correspondingly lower. L’Institut de Beauvais is almost every-
where attacked by leaf roll, only one or two isolated plots in the
north-east of Mayenne and the west of Sarthe being found free
from it. The Saucisse (Rouge Plate) suffers much more from
mosaic and leaf roll in Mayenne, Sarthe, and Vienne than in
Brittany.

L’Industrie is also very subject to these diseases, except in
Morbihan, where there is a sufficiency of healthy material to allow
of selection in order to obtain a regular supply of disease-free seed.
Early Rose and Chardonne, cultivated in the Cétes-du-Nord mainly
for export, are other varieties mentioned as equally lable to leaf
roll and mosaic.

The author again insists on the importance of systematic selec-
tion of the seed crop, and outlines a scheme for the establishment
in every department of special ‘selection fields’ for the use of
growers, accompanied by the distribution of awards and certificates
for healthy seed.

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

ae EP LIED MY COLOGY

Vou. I JULY 1923

SANDSTEN (E. P.) & Tompxins (C. M.). Degeneration in Colorado
Potatoes.—Colorado Agric. Hxper. Stat. Bull. 278, 15 pp.,
8 figs., 1922.

The results of an investigation of the degeneration of Colorado
potatoes, carried out during a period of four years with the Russet
Burbank and Brown Beauty varieties, at three localities in the
State, are described. The potatoes were divided into three series:
best hand-selected seed, best culls, and poorest culls obtainable. In
1918 at Del Norte, where the soil is a well-drained, sandy loam,
the highest yield in both varieties was obtained from hand-selected
seed, followed by the best culls. In 1919, when the experiments
were transferred to the heavy clay soil of Paonia, the hand-
selected Russet Burbank again gave the best yield; with Brown
Beauty, however, the good culls gave the highest yield and the
hand-selected seed the lowest. In 1920 at Del Norte the inferior
culls of both varieties out-yielded the hand-selected seed. In 1921,
at Eagle, where soil and climatic conditions are ideal for potato
growing, the best yield was obtained from the hand-selected seed.

The disease factor was almost entirely eliminated in the fore-
going experiments, less than 1 per cent. being present in any of the
plots during the period. Under Colorado conditions, therefore,
degeneration appears to be largely influenced by environmental
relations. Degenerate tubers planted in fertile soils in a favour-
able climate will, with proper attention, produce a superior crop.

It is recommended that every grower should have a special
seed plot from which the tubers of high-yielding and disease-
resistant plants are dug before the main crop each season and saved
for next year’s seed plot, the balance or major portion of the seed
harvested every year from the seed plot being used for general
planting.

GRAM (E.). Forsgg med avlsstedets indflydelse paa Kartoffelens
bladrullesyge. [Experiments in environmental influence on
the leaf roll disease of Potatoes.|—Tidsskrift for Planteavt,
XXvill, 5, pp. 769-806, 4 figs., 5 diag., 1922.

Experiments were carried on from 1915 to 1920 in various parts
G

290

of Denmark under the supervision of the phytopathological service
to test the influence of environment on the incidence of leaf roll
disease of potatoes. A brief historical account of the disease,
together with a full description of its symptoms, pathological
anatomy, and the various theories as to its cause, is given
in the present paper, and the previous work on its relation to soil,
climate, and the like is summarized. The view that the disease is
due to an ultramicroscopic organism is accepted. The Danish tests
were carried out with one healthy and one diseased strain of
Magnum Bonum potatoes, which were cultivated at eleven experi-
ment stations on a variety of different soils. Every autumn samples
of each strain from all the stations were forwarded to Kvistgaard
in the north of Zealand for further growth and comparison in the
following year.

The results of the experiments are described in considerable
detail. Tables are given showing the percentage of leaf roll plants
each year in the Kvistgaard plots, yield, and other details. Graphs
showing the effect of cultivation on the disease, at the different
stations are also given. In some of the stations the diseased strain
showed a tendency to recover; in others the healthy strain became
diseased. On the whole peat soils exerted the most favourable
influence on the crop, both as regards yield and freedom from the
disease. Sandy soils generally gave excellent results, almost equal
to the peat, while both the yield and condition of the crops were
adversely affected on light clay, except at one station, where a
satisfactory stand was obtained. Heavy clay soils were considerably
more favourable than light ones. Possibly the beneficial effects of
the peat and sandy soil were due in some measure to the earlier
maturity of the plants grown on them, which did not give time for
the passage of the virus from the aerial part of the plant through
the stolons to the tubers.

The influence of the soil, however, was not found to be the only,
or even the most decisive factor in the health or disease of the
potato crop. Meteorological conditions played an important part,
indeed the influence of climate on the disease appeared to be the
predominant factor. Any departure from the normal during the
period covered by the experiments was carefully noted. The con-
ditions governing the incidence of aphid attacks and the consequent
transmission of leaf roll are discussed. It was observed that damp,
cold weather in May and June was followed by a decrease in infec-
tion in 80 per cent. of the cases. The absence of disease in the peat
soils was probably largely due to the spring and autumn night
frosts in these situations, which retarded development in the
autumn, and in the spring frequently killed not only the young
growth but also the invading aphids. The districts in which these
so-called ‘sanatorium’ soils occur experience an average summer
temperature of less than 15-5°C.

The quantity of dry substance present in the tubers is regarded
as a further point of some importance. A reduction in the dry
substance, believed to result from storage in warm cellars, was
frequently associated with a corresponding loss from ‘ degeneration ’
in the next year’s crop. This is, however, apparently a distinct
phenomenon from leaf roll.

291

Leaf roll may be controlled by procuring seed tubers exclusively
from healthy fields, especially from parts of the country where
there is little infection. Such methods as field selection and the
use of large tubers are unreliable, at any rate in cases of severe
infection. The indirect control of the disease by combating the
aphids which are responsible for its transmission, the potatoes being
sprayed in early summer with Bordeaux’ mixture and nicotine, is
regarded as a promising line of attack. Early lifting of the tubers
to prevent infection through the stolons, and the selection of
resistant varieties are also worth further investigation.

SHARPLES (A,). A preliminary account of the fungi causing
‘brown root’ disease.— Malayan Agric. Journ., x, 7, pp. 181—
183, 1922.

During 1920 numerous cases of brown root disease were observed
on Hevea rubber trees on a Malayan estate. The chief symptom
was the well-known incrustation of the roots with masses of earth
and stones. Previous to 1917 the causal fungus of this disease
was referred to Hymenochaete noxia, but during that year Petch
obtained numerous fructifications of Fomes lamaoensis from tea and
rubber plants killed by brown root disease, and stated that the
so-called Hymenochaete was merely the result of abortive attempts
at the development of the Fomes sporophore.

Pure cultures on rubber wood blocks were obtained by the author
from the diseased roots mentioned above. At the same time the
fungus causing brown root disease of camphor (Cinnamomum
camphora), a large patch of which has been slowly dying out for
years at Kuala Lumpur, was isolated. The cultures were so dis-
tinct that they could scarcely be regarded as belonging to the same
fungus as the last. Further cultures were obtained from typical
specimens of brown root disease of Hevea rubber roots received
from Ceylon, and these again gave a fungus obviously different
from the other two. In every feature the three sets of cultures
were readily distinguishable from one another, except that they
had the peculiarity in common of secreting mucilage by the hyphae
when in contact with water. There can be little doubt that this
process accounts for the typical symptoms of brown root disease,
the secretion of mucilage causing the binding together of the
encrusting mass of earth and stones.

Thus there are at least three morphologically different, though
physiologically comparable, fungi. associated with brown root
disease. The camphor and the Ceylon rubber brown root fungi in
their final stages exhibit characters considered typical of the genus
Hyrmenochaete, while the Malayan rubber brown root organism
appears to be forming fructifications resembling those of a Corti-
coum. Further details regarding these fungi will be published
subsequently.

Osporn (T. G. B.) & SAMUEL (G.). Some new records of fungi for
South Australia, Part II, together with a description of
a new species of Puccinia.—TZ'rans. Roy. Soc. S. Australia,
xlvi, pp. 166-180, 1 pL, 4 figs., 1922.

In this paper records are given of fifty-one fungi new to the

292

South Australian flora, of which one, Puccinia semibarbatae on
Bulbine semibarbata, is new to science.

Amongst species parasitic on cultivated plants the following are
of interest :

Phoma macrophoma, Diplodia citricola, Septoria depressa, and
Coniothecium scabrum on orange, the first on the twigs, the other
three causing scabbing of the fruit; Phyllosticta brassicicola on
Brassica oleracea; Septoria lycopersict on tomato; Vermicularia
circinans [Colletotrichum circinans] on onion; V. varians (‘black
dot’ or dartrose disease) on potato; Gloeosporium ribis on goose-
berry canes and leaves; Cercospora apii causing a leaf spot of
parsnips (Pastinaca sativa) ; Coniothecvwm chomatosporum causing
cankers on twigs of apple and pear, scabbing of fruit has so far
not been recorded in South Australia; Psewdomonas juglandis on
stems, leaves, and fruits of walnut (Jwglans regia), a serious disease
which has spread to almost all places where walnuts are grown,
and which makes it impossible to obtain a marketable crop from
many trees; Bacteriwm mori causing angular, black spots on the
leaves of mulberry (Morus nigra).

Plasmopara viticola, which appeared first in Australia at
Rutherglen, Victoria, in the season 1916-17, spread eastward,
reaching Queensland in 1920-21. Its progress to the west was
slow, its occurrence in Mildura being only reported in the season
1920-21, and from thence it spread down the Murray to Renmark,
Berri, and Watervale. It is possible that infection may have been
conveyed by human agency as there is regular motor traffic between
Mildura and Renmark, but the spread is thought to be more
probably due to air-currents, though the distances involved are
considerable, varying from 100 to 230 miles. The attacks in
South Australia have so far been slight, and it is not thought that
climatic conditions will favour the development of the fungus.

OsporN (T. G. B.). A note on the pathological morphology of
Cintractia spinificis (Ludw.) McAlp.—Trans. Roy. Soc. S.
Australia, xlvi, pp. 1-5, 1 pl., 5 figs., 1922.

This smut causes certain interesting pathological changes in the
host [Spinifex: hirsutus Labill].

In the male inflorescence, instead of the normal spikelet com-
posed of two sterile glumes, or three sterile and one flowering, and
with each floret consisting of glume, palea, two lodicules, and three
stamens, the smutted spikelet has two sterile glumes and two
florets, the latter being without lodicules. The anthers of the
smutted flower contain no pollen and the filaments do not elongate.
Above the point of insertion of the stamens an irregular conical
mass, 1 to 7 mm. in length, is produced, consisting of a central core
of host tissue coated, in the ripe smut gall, with a spore layer.
Other changes are the greater elongation of the internodes of
smutted inflorescences, reduction in the number of secondary axes
in the inflorescence, closer aggregation of spikelets, and increase in
their number per secondary axis.

The main divergences of a diseased female inflorescence from the
normal are elongation of the internode below the terminal head, com-
plete absence of the long sterile spines which are so marked a feature

293

of the normal inflorescence (a few sterile spines may be present, but
these are shorter than the fertile spines, of which the head is largely
built up), insertion of the spikelets on the fertile spines at a distance
of 1-5 to 4 em. from the base instead of being borne at the extreme
base, and increase in length of the spines themselves up to 15 em.
in length (i.e. half as long again as normal). The smutted female
spikelet consists of two sterile and two fertile glumes, as against
three sterile glumes (or two sterile and one abortive male flower),
and one fertile glume in the normal spikelet. The lower floret,
normally an abortive male, behaves like a female in the smutted
heads and is indistinguishable from the upper, fertile one. The
smutted flower has glume and palea, both longer than usual, the
latter being often involved in the smut gall, but no stamens have
been recognized, the whole of the floral axis above the palea being
an elongated, rarely bifurcated, smutty mass.

The smut galls in both the male and the female inflorescences are
similar, except that the former is usually somewhat smaller.
Owing to the extensive modifications produced by the gall formation,
however, it is not safe to conclude that ovaries are actually pro-
duced in male flowers as a result of the attack, as has been reported
in the case of certain other smuts.

TROTTER (A.). Osservazioni intorno ad alcuni Erisifacei italiani
meno noti. [Notes on some less-known Italian Erysiphaceae. ]
—Ann. R. Scuola Sup. di Agric. in Portici, 2nd ser., xvii,
pp. 3-11, 1922.

Notes are given on three Erysiphaceae of economic importance as
well as of scientific interest, observed in Italy.

The appearance and wide dissemination of the oak mildew in
Europe is described, and the records of the discovery of its peri-
thecial stage in various parts of Europe discussed. The author has
examined perithecia found in Sicily late in 1920, and states that
they agree with previous French and Italian records, except in the
somewhat smaller size of the asci and ascospores. He identifies the
fungus as Microsphaera quercina (Schw.) Burr., a species grouped
by Salmon under M. alii, and referred by Neger to M. alni var.
quercina, The almost simultaneous appearance of the ascigerous
stage in France, Germany, and Italy he regards as being due not to
any special climatic influences, but to internal causes in the fungus
itself, probably connected with its acclimatization. |

American gooseberry mildew (Sphaerotheca mors-uvae) appears
to have been actually first recorded in Italy by Voglino in the
province of Turin in 1904, but this record has escaped most recent
writers. The fungus is now present in Turin, Pavia, Milan,
Venetia, Novara, and other districts, and even far to the south in
Avellino. The cultivation of gooseberries is, however, so limited
and seattered that serious economic losses are not to be anticipated.

Apple mildew has received scant notice in Italy, though it is
present not only in the north of the country, but also, apparently
of recent introduction, in Avellino. There is no doubt that the
disease is widely diffused in its conidial form in Italy. The
ascigerous stage appears to be seldom developed, and there is
accordingly some doubt as to the species concerned. It is not

294

improbable that the two fungi, Podosphaera leucotricha and P. oxy-
acanthae, occur in Italy, but in the Avellino cases examined by the
author the conidial stage could not be referred to the latter, and P.
leucotricha was probably concerned. The disease appears to be
increasing in Italy, its spread being assisted by the use of infected
wild apple seedlings from northern Italy as stocks. It was noticed
that wild apples grown from seed were severely attacked whereas
after grafting they were almost immune.

Nannizzi (A.). Sulla forma ascofora dell’ Oidium quercinum
Thiim. [Notes on the ascigerous form of Ozdium quercinum
Thiim.]—Riv. Patol. Veg., xii, 7-8, pp. 87-90, 1922.

The author records the finding of perithecia of the oak mildew
in the Sienna district. He agrees with views expressed by some
other Italian observers that their development was induced by
a sudden lowering of the temperature after a prolonged heat wave.
They were chiefly on mature leaves, which were covered with them,
but numerous examples occurred also on young leaves at the tips of
the shoots. Only Quercus pedunculata bore them, Q. sessiliflora,
Q. cerris, and Q. alex having no perithecia, though their leaves bore
the conidial stage.

The perithecia, which are referred to Microsphaera quercina,
agreed in their main characters with the previous Italian deserip-
tions.

Percu (T.). Some diseases of Tea.—Trop. Agric., lix, 4, pp. 243-
249, 1922.

A leaf disease due to Cercosporella theae, which was not observed
between 1909 and 1919, has attracted much attention in up-country
districts in Ceylon, since the latter date [see this Review, 1, p. 331].
The disease, which is almost invariably found in the neighbourhood of
acacias, appears towards the end of the monsoon rains, first on the
acacias and then spreading to the tea; it is found mostly at alti-
tudes above 4,000 ft. Numerous black spots are produced on the
young leaves, and in wet weather the whole leaf may become black
and rotten. On older leaves the spots are at first black, and then
may turn grey, with a raised, purple border. Full-grown leaves are
marked with large, diffuse, mottled brown patches, which turn grey
with age and have a narrow, purple-black, marginal band. In
severe cases the bush may be almost defoliated. Attacks on the
green stems occur in the form of purple, sunken areas. The fungus
is visible as a fine, white web over the spots and on the surrounding
areas of the under surface of the leaf. The long, rod-shaped spores
are borne on this superficial mycelium in white clusters. The
return of fine weather after the rains arrests the disease.

A stem disease caused by Aglaospora aculeata, formerly some-
what rare, appears also to be on the increase. It is believed to be
confined to the up-country districts. The fructifications of the
fungus are formed beneath the bark, the outer layers of which
eventually crack as a result of pressure from within. The apices
of the fructifications protrude through the fissures as conical, black
thorns, arranged in straight lines or circles. The wood of infected
branches is dark brown in colour, and brittle but not soft. Unless

295

checked, the fungus spreads into the main stem and may even
travel down to the roots, ultimately killing the bush. Infection is
conveyed by means of spores extruded from openings at the apices
of the thorns. The stems are apparently infected at pruning cuts.
Tea is so far the only known host of the fungus. The dead
branches should be removed and burnt, but the complete eradication
of the fungus often involves collar pruning.

Red root disease (Poria hypolateritia), the symptoms of which
are described in detail, is very common in young clearings, originat-
ing on the stumps of Bombu [Symplocos spicata], Doon (Doone
zeylanica), and other jungle trees. Directions are given for the
eradication of the fungus, which has been known to destroy over
two thousand bushes in an area of twenty-six acres in six years.

Acacia stumps are liable to attack by various large root and stem
fungi, e.g. Fomes applanatus, Armillaria fuscrpes, and Irpex
destruens, all of which are capable of attacking tea. Acacias are
now extensively used for interplanting with tea, and, in view of the
danger of infection by these fungi, the stumps should be extracted
whenever possible if it becomes necessary to remove the trees.

SrpEnius (E.). Verslag van het Deli Proefstation over 1 Juli
1921—30 Juni 1922, [Report of the Deli Experiment
Station from 1st July 1921 to 30th June 1922.|—Meded. Deli
Proefstat. te Medan-Sumatra, Ser. 2, xxiv, 64 pp., 1922.

Experiments were conducted to test the value of Mimosa invisa
when used as a green manure for tobacco in reducing the incidence
of slime disease [Bucillus solanacearum]. Observations and in-
vestigations of many years’ duration had already shown that M.
invisa not only improves the soil but also suppresses the develop-
ment of the hosts of B. solanacearum. It has the further advantage
of being easily and inexpensively cultivated, though it is subject to
sporadic attacks from Sclerotiwm rolfsii. The recent tests showed
that no marked improvement can be expected unless the Mimosa is
grown for a year or more before being ploughed under. The effects
on the slime disease of liming the soil were also studied. Negative
results were obtained, except in one plantation of loose red soil con-
taining quartz, where the application of three tons of lime per bouw
[1-79 acre] reduced the infection from 33 per cent. to 6 per cent.
The incubation period of slime disease on tobacco was found to be
approximately six days for seedlings about 5 cm. in height, ten
days for seedlings ready for transplanting, and eleven to thirty
days for plants in the field.

The practice of hilling is frequently held responsible for the
aggravation of slime disease, but experiments proved that this is
not the case. Hilling was, moreover, found to be indispensable to
the proper development of the crop. Seedlings from healthy beds
sown in infected ground were found to be considerably less suscep-
tible to slime disease than apparently sound and strong seedlings
from infected beds (30-8 per cent. of infection as against 41-1 per
cent.). Tests of varieties selected for resistance to this disease were
continued. Promising results were obtained with one of the
selections, and it is proposed to carry out extended tests of this
strain.

296

Phytophthora [nicotianae| was prevalent on tobacco seedlings
ready for transplanting, probably on account of the heavy rains
while the plants were in the seed-bed. Ricinus communis was
attacked by an allied and possibly identical species of Phytophthora.

Specimens of field tobacco submitted for examination were found
to be attacked on the stalks by a species of Pythiwm. On two
estates the epidemic was so severe that scarcely a single plant
remained healthy. Both the sites in question were formerly
occupied by cattle-sheds. The application to the transplant holes
some days before planting of a 1:500 solution of formaldehyde
greatly reduced the infection. Treatment with uspulun was in-
effectual.

Ramsey (G. B.). Basisporium gallarum Moll., a parasite of the
Tomato.— Bot. Gaz., |xxiv, 3, pp. 325-328, 11 figs., 1922.

A rot of ripe tomato fruit shipped from California in 1919 was
found to be due to Basisporium gallarum, a fungus originally
observed by Molliard on dead larvae of Lipara lucens, within galls
which this insect produces on Phragmites communis. Although
the presence of Basisporiwm in cultures from maize, wheat, and
dewberries has since been reported, no parasitic activities appear to
have been attributed to it previously. Inoculation experiments
indicate that it is a vigorous wound parasite which produces soft,
red, blister-like lesions on ripe tomato fruits. The lesions may
reach a diameter of two inches in four days. Green fruits react to
the inoculation, but in a lesser degree, while a temperature of 9° to
10° C. inhibits the development of the fungus even on ripe wounded
fruit. An abundance of pale, smoke-coloured mycelium develops
on the fruit when the latter is kept in a humid atmosphere after
inoculation.

Cultural experiments are described, which show that the extreme
temperatures for growth are approximately 10° and 35°C. A\l-
though the Californian fungus exhibits a few minor morphological
differences from the description of Molliard’s form, and the substrata
on which the two were found differ widely, the author does not
feel justified in creating a new species for this tomato parasite.

TROTTER (A.). Intorno al seccume degli aghi ed agli altri fenomeni
patologici del Pino domestico (Pinus pinea L.). [Notes on
needle blight and other pathological phenomena of the Stone
Pine (Pinus pinea L.)|—Riv. Patol. Veg., xii, 7-8, pp. 91-106,
4 tigs., 1922.

The needle blight of the stone pine (Pinus pinea) in Campania
may be due to physiological causes (as in the vicinity of Vesuvius,
where the gases emitted from the crater affect the trees) or to the
attack of parasitic fungi. The author describes a case of the latter
from near Avellino, where it is sometimes epidemic. Towards the
end of spring the needles turn light green in colour, later becoming
yellow, and then brown as they dry up. Those situated near the
tips of the twigs are most affected, and a high proportion of shoots
is usually involved, so that the disease is very noticeable. The
symptoms on the individual needles vary: the apex may be

297

yellowed and withered, the base remaining green for a time; the
needles and their sheaths may dry up uniformly ; there may be
nothing more than a slight contraction of the tissues or a discoloured
spot resembling a bruise; drops of resin may exude, especially
towards the base and on the sheaths; and finally, the presence of
blackish dots may be observed on the surface of the needle and its
sheath and on the adjacent epidermis of the twig. These dots are
the fructifications of two distinct fungi, a Pestalozziu and a Clado-
sporium. The former is considered to be a new form, f. pini-
prneae, of Pestalozzia hartigii, resembling most closely P. truncata
Léy. amongst the other species of this genus found on conifers. Its
mycelium penetrates the needles as fine, hyaline hyphae, 2 to 2*5 yp
in diameter and much more sparingly septate, less tortuous, and
less branched than those of the Cladosporium. The conidia are
borne on a stromatic layer of gelatinous, interwoven hyphae, and
are difficult to find.

The Cladosporium is regarded as a new form, f. pini-pineae, of
C. laricis, previously only known on the larch. It differs from the
normal type chiefly in attacking the sheaths, and sometimes even
the twigs, as well as the needles, which alone are attacked in the
larch. Fructifications are found more readily on the sheaths than
on the needles; on the latter usually only small stromata, occupy-
ing the substomatal cavities and protruding very slightly from the
stomata, are formed. The mycelium is confined to the outer
parenchyma of the needles.

The exact part played by these fungi in the production of the
needle blight described in this paper has not been established.
Frost is believed by the author to be an important factor in the
disease, which is much more prevalent at an altitude of 600 m.
than near the town of Avellino, which is only 300 m. above sea-
level.

An annotated bibliography of fifty-nine references to diseases,
pests, and teratological phenomena affecting the stone pine is
appended.

Sreup (T.). Een ziekte (Aecidium cinnamomi Rac.) van den
Tedjo (Cinnamomum iners Bl.). [A disease (Aecidiwm cinna-
momi Rac.) of Tedjo (Cinnamomum ‘ners Bl.).|—Tectona
[Buitenzorg, Java], xv, 4, pp. 348-350, 1922.

Tedjo (Cinnamomum iners) trees at Batoe Raden examined in
1919 were found to be in a withered and dying condition. The
leaves, petioles, and branches, especially of the upper part of the
tree, and sometimes also the trunk, were affected. The diseased
leaves and twigs exhibited a black discoloration, the latter also
becoming noticeably swollen.

All the affected parts were covered with the orange-coloured
aecidia of Aecidium cinnamomi Rac. Unless subsequent investi-
gations prove that the form occurring on C. iners is biologically
restricted to that host, there is every likelihood that the disease
may spread. to the cultivated cinnamon [C. zeylanicwm]. Pending
further investigations, the only control measures which can be sug-
gested are the excision and burning of all affected parts.

G2

298

SAMUEL (G.). Notes on forest pathology from South Australia.—
Australian Forestry Journ., v, 7, pp. 189-192; 8, pp. 223-
226; and 9, pp. 253-254, 7 figs., 1922.

The author, while stating that at present parasitic diseases are of
no great importance in South Australian forests, calls attention to
the neglect throughout Australia of forest pathology which may
well lead to the introduction of new pests from abroad or to the
dangerous development of hitherto negligible diseases already
present in the country. He advocates, therefore, the appointment
of at least one qualified forest pathologist, whose duty would be to
protect the interests of sylviculture.

The main interest of these papers lies, however, in the description
of a remarkable ‘disease, locally known as ‘ curly-needle disease’, of
Pinus muricata and P. imsignis observed at Kuitpo, South
Australia, but stated to exist also in Victoria and Western Australia.
The most characteristic symptom is the effect on the leaves. The
three needles in each group are often fused together, curved, and
shortened ; the thickened compound needle may be not more than
a third of an inch in length. Sometimes the needles are united
without being shorter than usual, and the different degrees of
deformity may be found, together with normal needles, on the
same tree or even on the same years growth. A less constant
symptom is the elongation and greening of the bracts subtending
the needle bunches; this is less frequent and less pronounced in
P. insignis than in P. muricata, in which the bracts may become
14 in. long and 4 in. wide at the base. In the latter species the
dead male cones are often retained in large numbers on the affected
trees for a considerable time. The disease develops in trees up to six
years old, after which age they appear to beimmune. The symptoms
frequently arise in trees apparently growing strongly, but the result
is invariably to arrest or greatly retard further growth. Old cases
have a peculiarly tufted appearance due to copious branching of
the lateral shoots. In P. insignis the leading shoot and some of
the side branches may be killed outright. There seems to be no
regularity in the distribution of affected trees ; although occasionally
two or three may occur together, it is far more usual to find a
diseased tree surrounded by perfectly healthy ones. No corre-
lation has so far been established between the occurrence of the
disease and soil or other environmental conditions, and its cause is
as yet entirely unknown. It has been suggested that it is the result
of the attacks of Chermes, and that an aphis is embedded in the
tissue at the base of each curly-needle bunch, but the author was
unable to discover any grounds for this belief. He was also unable
to find any fungus constantly associated with the disease, and many
of the symptoms are directly at variance with those usually con-
nected with fungous diseases. The disease is considered to have
points in common with the group of physiological diseases of which
tobacco leaf curl is a type; the latter is hereditary and trans-
missible by insects and inoculation, though it is not caused by any
known fungus or bacterium. .

Brief notes are also given on the effects of the ‘smothering
fungus’ Thelephora terrestris (T. laciniata) and of Armillaria
mellea on Pinus insignis, as well as a short account of a shoot
disease associated with a fungus of the Fusicoccewm type.

299

BIRMINGHAM (W. A.). Disease of Pinus insignis at Strickland
State Forest, Natara.—Australian Forestry Journ., v, 8,
pp. 206-211, 5 figs., 1922.

The author gives a detailed description of a disease of Pinus
insignis, found at Natara, New South Wales, which is evidently,
in part at least, the same as that referred to in the above abstract
as ‘curly-needle’. Inoculation experiments made with two species
of fungi (Sphaeropsis and Pestalozzia) that were common on the
dead needles gave negative results, and the disorder is believed to
have a physiological origin. An additional symptom besides those
mentioned by Samuel is the development of a long main axis free
from lateral growth and with a mop-like head. A profuse develop-
ment of needles along the main axis may also occur.

Mu.uer-THure@au (H.). Die Gloeosporium-Krankheit der Hol-
underbeeren. [The Gloeosporiwm disease of Elderberries.]—
Landw. Jahrb. der Schweiz, xxxvi, 6, pp. 826-828, 1922.

The causal organism of a widely distributed disease of elder-
berries (Sumbucus nigra) was isolated and found closely to
resemble Gloeosporium fructigenum | Glomerella congulata], which
produces bitter rot of apples. Cross-inoculation experiments with
the elderberry organism and G. fructigenum were undertaken, the
results of which showed that the elderberry Gloeosporiwm was
incapable of infecting apples. Elderberries inoculated with G.
fructigenum from apples were eventually infected, but only when
their skin had become ruptured after standing in water for some
time. Ripe berries of Swmbucus ebulus were also proof against the
attacks of the elderberry Gloeosporiwm.,

Notwithstanding the morphological agreement between G. fructi-
genum and the elderberry organism, the author thinks that the
latter must be regarded as a biological variety, for which the name
G. fructigenwm var. sambuci is proposed.

Linprors (T.). Studier é6ver Fusarioser. II. Om Fusariuman-
grepp pa spida Barrtradsplantor. [Studies in Fusarioses.
II. Fusarium attacks on Conifer seedlings. |—Centralanst.
jor foérséksvdsendet pa jordbruksomradet Medd, 238, 24 pp.,
1 col, pl., 4 figs. 1922. (German summary.)

After a brief discussion of previous work on the damping-off of
conifer seedlings, the author describes his experiments with Pinus
sylvestris in 1916 and 1917. In the first isolations made from
material submitted for examination from Osby [south Sweden],
only one species of Fusariwm (a form resembling F’, redolens except
that it produced sporodochia and pionnotes sparingly, had many
4- to 5-septate conidia, and bore chlamydospores) was found. In
a later experiment with seedlings grown in sterile soil in pots,
a spontaneous outbreak of Fusariwm occurred and five species of
the genus were isolated from twenty seedlings, namely, F. meta-
chroum from ten plants; F. subulatum, F. solani, and F. macroxy-
sporum n. sp. each from three; and F. cf. sclerotioides from two.
This last species agreed in the main with Ff. sclerotioides var.
brevius (F. blasticola), but differed in the production of 4- and 5-
septate conidia, and in the size and number of the sclerotia. The

300

new species, F. macroxysporwm, of which .a Latin diagnosis is
given, is allied to F, ewoxysporwm, from which it differs in the
greater breadth of the conidia, and also to F. awrantiacum, from
which it may be distinguished by the rarity of conidia with more
than three septa and the absence of blue sclerotia. Its mycelium
rapidly becomes covered on most substrata with a layer of conidia
resembling pionnotes. The few sclerotia which occur are light
brown in colour. On rice and wheat flour cake the plectenchyma
assumes a diffuse purple coloration. The conidia are generally 3-,
but sometimes 4- and 5-septate, while in older cultures micro-
conidia occur, continuous or with one or two septa, and chlamydo-
spores, both intercalary and terminal, are also formed.

Inoculation experiments with these six species and also Ff.
culmorum and F. subcarnewm were carried out on pine seedlings
grown in sterilized soil in pots. The most severe attacks were
caused by F. metachroum, F. subulatum, F. culmorum, and F.
macroxysporum, but in all the inoculated pots the number of
diseased seedlings was greater than in the controls. The author
isolated from various soils all the pathogenic species of Fusarium
mentioned above, with the exception of the species resembling F.
sclerotioides and F. redolens, while infection was also proved to be
transmitted by the seed. Steeping the seed for fifteen minutes in
0-1 per cent. formalin reduced infection from this source to a
minimum. Further experiments were undertaken to ascertain the
effect of soil sterilization both on the host and on the parasites used
in the above experiments. The germination of the seed and growth
of the seedlings was found to be, if anything, improved when
sterilized soil was used, and some of the fungi also grew better in
the extract from sterilized than in that from unsterilized soil. In
inoculation experiments with F. macroxysporum a much larger
number of seedlings became diseased in the former than in the
latter soil.

The methods of control advocated by other investigators are
summarized, no work on these lines having been undertaken by the
author himself. They include disinfection of the soil with sulphuric
acid, formalin, copper sulphate, or zine chloride, all of which have
given satisfactory control in various places, and steeping the seed
in copper sulphate, corrosive sublimate, or formalin. From state-
ments in the literature it would appear that Abzes concolor, Pinus
ponderosa, P. sitchensis, P. pungens, Picea engelmannia, and Larix
leptolepis are very susceptible to damping-off, while Picea eacelsa is
almost immune. Neger’s statement that the common pine (P.
sylvestris) is also almost immune is contradicted by the present
investigations in which it proved extremely susceptible.

MorqueEr (R.). Sur un nouvel héte du Trametes hispida (Bagl.).
[On a new host of 7’rametes hispida (Bagl.).|—Bull. Soc. Myc.

de France, Xxxviii, 3, pp. 170-172, 1922. s

The author describes the occurrence of Trametes hispida [T.
trogii Berk.] on Schinus dependens—apparently a new host—in
the Botanical Gardens of Toulouse. The mycelium was found to
follow the axis of the trunk to a considerable distance (about
1 metre) occupying the medullary region and penetrating radially

301

into the surrounding wood for 2 to 3 cm. from the pith. This
resulted in the formation of a continuous strand composed of wood
fibres interwoven with the mycelium. At certain points the latter
reached the surface and produced fructifications. The affected
areas were yellowish-white, in contrast to the pale pink of the
healthy wood.

The diseased wood was spongy in texture, the fragments softened
by the action of the fungus possessing a certain amount of elas-
ticity ; the wood fibres were also easily dissociated. At the margin
of these softened areas, brown, sinuously concentric zones were
formed, probably as a result of the action of oxydizing enzymes
whose presence was demonstrated by the author.

The fungus was successfully isolated and grown in culture,
details of which are given. Sporophores do not appear to have
been formed in culture.

Manns (T. F.). Cabbage wilt and stem rot in Delaware.— Delaware
Agric. Exper. Stat. Bull. 132, 24 pp., 13 figs., 1922.

Cabbage wilt or yellows, due to Fusarium conglutinans, and
stem or foot rot (Phoma lingam) have caused heavy losses to
Delaware growers during recent years. The symptoms of the
diseases are described and figured, the trouble in both cases being
traced to the seed-bed. Investigations were carried on from 1914
to 1917 to ascertain whether the yellows resistant strains selected
by L. R. Jones in Wisconsin from the variety Ball Head were of
any value in Delaware. The results of these experiments were, on
the whole, not very promising. It was found, however, that
desirable wilt-resistant strains, of both early and late varieties,
could be produced on wilt-sick land by the following method.
Duplicate seed-bed rows were planted forty-two inches apart, the
non-resistant seedlings being thinned out until a uniform stand of
highly resistant plants was secured. The latter were finally
thinned out to a distance of one foot apart. The varieties that
gave good results under these conditions were Jersey Wakefield,
Drumhead Frost Proof, and Nokor or Volga. Resistance to wilt
does not ensure the absence of stem rot.

The following control measures are recommended: rotation of
crops, disinfection of the seed with corrosive sublimate, and a
liberal application of well rotted manure combined with a potassium
fertilizer.

Mivpratsu (D. G.). Alternaria from California.— Bot. Gaz., |xxiv,
3, pp. 320-324, 2 figs., 1922.

A disease of cabbage, cauliflower, and broccoli, confined to a dis-
trict of California where high relative humidity and a uniform
temperature prevail, was found to be due to an apparently un-
described species of Alternaria. Its chief symptom is the appear-
ance, generally on apparently vigorous leaves of all ages, of
numerous circular, somewhat sunken, purplish-black spots, the
centres of which are darker than the margins. The zonation
characterizing the lesions produced on leaves of cabbage by A.
brassicae is lacking. Sporulation of the fungus is sparse on still
vigorous leaves, but becomes profuse on yellow and detached leaves.

302

Cultures were readily obtained and the disease reproduced by
inoculation. Under dry conditions in the field only a small speck
developed, but large spots up to 1 to 1-5 cm. were produced in
seven days in plants kept in a very moist atmosphere. In view of
the differences in morphological characters between this fungus and
A. brassicae, and its different effects on the host, the author names
it A. oleracea n. sp., a full English description being given.

OSTERWALDER (A.), Ein Rotbrenner-Bekimpfungsversuch. | An
experiment in the control of ‘ Rotbrenner’.|—Landw. Jahrb.
der Schweiz, Xxxvi, 6, pp. 831-832, 1922.

As a rule the liberation of the spores of the ‘ rotbrenner’ fungus
(Pseudopeziza tracheiphila) takes place during the latter half of
May. A severe epidemic of the disease in 1918 led to a series of
experiments in its control in the following spring, especially on the
susceptible Miller vines. It was found that spraying with 1-5 per
cent. Bordeaux mixture reduced the amount of infection to a
minimum. ‘The application of the mixture took place on 6th June
1919, but such a delay was only possible on account of the dry,
hot weather of that year. In general, about the 20th May would
be an appropriate date in the Wadenswil area.

MiLuer-THurGavt (H.), OSTeRWALDER (A.), & JEGEN (G.). Pflanzen-
physiologische und pflanzenpathologische Abteilung. [De-
partment of Plant Physiology and Pathology. |—Ber. Schweiz.
Versuchsanst. fiir Obst-, Wein-, und Gartenbau in Wadenswil,
1917-20. Landw. Jahrb. der Schweiz, xxxvi, 6, pp. 774-784,
1922.

This short review of the diseases of orchard, vineyard, and
garden crops observed in Switzerland during the years 1917-1920,
contains many records of interest.

Amongst fruit diseases it is stated that the quince disease caused
by Sclerotinia linhartiana, which was formerly very prevalent,
appears to be declining in importance, while Entomosporvwm macu-
latum [Fabraea maculata] seems to be on the increase and causes
considerable damage to this host. Quince mildew (Ozdiwm cydo-
niae) was also recorded. Xylaria polymorpha was found on the
collar of a diseased pear tree, and the white spot disease of pear due
to Mycosphaerella sentina is increasing greatly, and on certain
varieties causes a premature leaf fall. Fusariwm putrefaciens was
found causing a core rot of apples. The raspberry cane blight
caused by Didymella applanata has steadily increased in Switzer-
land of recent years.

The control of downy mildew of the vine (Plasmopara viticola)
is improving and also that of the ‘rotbrenner’ disease (Pseudo-
peziza tracheiphila) and scab (‘ grind’) as these diseases become
better understood. White or livid rot (Coniothyriwm diplodiella)
was only once reported, while Botrytis cinerea did considerable
damage, not only by rotting the grapes but also by attacking the
pedicels and causing them to dry up during damp weather in the
autumn.

There was one interesting case of a bacterial disease of tomatoes
which almost destroyed a considerable area under this crop in the

303

canton of Ticino. The affected plants were wilted, and on examina-
tion the tissues bordering on the medulla were found to be dis-
organized. On sectioning the diseased stems, drops filled with
bacteria exuded. The characteristic green, transparent areas on the
leaves (‘oil spots’) were also swarming with bacteria. The infection
of the stems is believed to be secondary to that of the leaves, in
which case an early application of Bordeaux mixture would be
beneficial. Bean and pea seedlings, lettuce, and mangolds were also
attacked by unspecified bacterial diseases, and tobacco leaves by
Bacillus maculicola.

A long list of the parasites recorded on potatoes and the principal
vegetable crops is given, mostly common or well-known troubles.
The roots of pea plants submitted for examination were found to be
infected by Thielavia basicola.

Amongst the miscellaneous diseases observed were attacks of
Phytophthora ommivora on calceolarias, asters, and gooseberries.

Division of Botany, Department of Agriculture [Canada]. Survey
of the prevalence of plant diseases in the Dominion of
Canada, 1922.—Third Ann. Rept., pp. ii+ 1-63 and 184-192,
1923. [Mimeographed.]

This record of the prevalence of plant diseases in Canada during
1922 is based on the reports of collaborators in the various Pro-
vinees, edited by F. L. Drayton, Plant Pathologist at Ottawa. The
report on potato diseases, which is separately issued, is noticed
elsewhere [see below, p. 332]. The following summary covers some
of the more important points.

Stem rust (Puccinia graminis) caused very little damage to
wheat in Alberta and Saskatchewan, the losses from the disease
being the slightest recorded since 1915. In Manitoba the rust was
very severe on wheat growing within a 30-yard radius of some
barberry shrubs at the Agricultural College, Winnipeg. Pycenidia
were observed on the barberry on 15th May, and open aecidia three
days later, about a fortnight earlier than the previous year. The
wheat in the adjoining plots showed rust spots on 25th June. Beyond
the 30-yard radius, infection occurred only on the leaves until
after 12th July. Severe infection was observed in fields entirely out
of reach of the barberry infection centre, and also occurred in some
other parts of the Province, while the rust was absent from some
areas. In New Brunswick the disease was general but not very
severe. Heavy losses were reported from Prince Edward Island.
On late oats, stem rust was very severe in all the provinces. Crown
rust (Puccinia coronata) [P. lolii] was very prevalent in the
aecidial stage on buckthorn (Rhammnus catharticu) in southern
Saskatchewan in the early summer and was responsible for very
heavy losses in the oat crops of southern Saskatchewan, Manitoba,
and Ontario. Leaf rust of wheat (Puccinia triticina) was less
prevalent than in 1921, while leaf rust of rye (P. dispersa) was
common but not severe.

Bunt of wheat (Tdletia tritici and T. levis) was on the whole less
prevalent and severe than loose smut (Ustilago tritici), except in
Wentworth County, Ontario, where it caused most serious financial
losses. Loose smut of oats (Ustilago avenae) was very bad in some

304

parts of Ontario, and was general in New Brunswick and Prince
Edward Island. Covered smut (Ustilago laevis) was not of much
importance. Wheat scab (Gzbberella sawbinetit) was widespread in
New Brunswick and Prince Edward Island. Glume spot (Septoria
nodorum) has caused a severe reduction in the New Brunswick
wheat crops since 1918, and no control measures have given promis-
ing results. Dawson’s Golden Chaff is highly resistant to this
disease. Crinkle joint of wheat, due to an unknown cause, and
characterized by a kinking of the lower internodes of the stem,
occurred in Alberta and Saskatchewan. Head blight and stem rot
of wheat (Helminthosporiwm sativum) was common in Saskatche-
wan. Leaf spot or scald of barley (Rhynchosporiwm secalis) was
reported at Edmonton, Alberta, for the first time in Canada in
1921, and again occurred in 1922. Other cereal diseases reported
were of minor importance.

Powdery mildew (Zrysiphe polygoni) was extremely widespread
and severe on clover in Ontario, New Brunswick, and Prince
Edward Island. Flax rust (Melampsora lini) caused considerable
injury to the fibre qualities of plants at the Ottawa Central Experi-
mental Farm, while wilt (Fusarium lini) was very prevalent in
some parts of southern Saskatchewan. Sclerotinia wilt of sun-
flowers (probably S. libertiana) was severe and widespread in
Quebec, and also caused the death of 45 per cent. of the plants
grown for seed at the Central Experimental Farm, Ottawa. Rust
(Puccinia helianthi) was very common on this crop, but did not
generally do much harm.

Apple scab (Venturia inaequalis) was common everywhere
except in British Columbia, but was well held in check by spraying.
Fire blight (Bacillus amylovorus) of apples and pears was very
serious in British Columbia and Ontario. Collar rot of apples
(Armillaria mellea) was very severe in British Columbia, where it
results in the loss of thousands of trees annually. Rust of currants
(Cronartium ribicola) was recorded for the first time on Prince
Edward Island in a plantation of black currants, where 90 per
cent. of the leaves were infected. White pines [Pinus strobus] in
the vicinity showed no signs of the disease.

Root rot of pears, due to various fungi, caused a loss amounting
to $12,000 in one county of Ontario alone. Wilt and blight of
canning peas, probably due in part to a species of Fusariwm, also
caused heavy losses. A rusty browning of asparagus tips, the
cause of which is obscure, rendered much of the crop unmarketable
in New Brunswick, Quebec, and Ontario.

Many other diseases besides those mentioned above are recorded
on cereals, fodder, fruit, and vegetables, and the report terminates
with a survey of the diseases of ornamental plants and of shade
and forest trees.

NicHoutis (H. M.). Annual Report of the Government Micro-
biologist.— Agric. & Stock Dept., Tasmania, Rept. for 1920-21,

pp. 10-14, 2 pl., 1922.
In the section of the report devoted to the fungous diseases of
plants it is stated that club-root of cabbage (Plasmodiophora
brassicae), which occurs mainly on acid soils and is aggravated by

305

the use of acid chemical fertilizers, appears to be on the increase in
Tasmania, though it can be controlled by liming the soil. A similar
organism has been found attacking the roots of hops in some parts
of the island. The only previous record of the latter disease is
from New Zealand, where it was described under the name of
Plasmodiophora humuli. The roots of the plants decay and are
finally destroyed, the hops becoming sickly and unproductive for
some time before they die. The spores are spread by the water
used for irrigation in the hop-gardens. P. humuli strongly
resembles P. brassicae, and would probably yield to similar
measures of control.

In October 1919 potato seed of the Brownell variety was heated
to a temperature of 125° F. for four hours with the object of
destroying various seed-borne diseases. The potatoes were then
planted in an acre of new ground and twice sprayed with Bordeaux
mixture 4-440, the first application being given when the plants
were nine inches high, and the second when they were fully
developed. Only a small proportion of the resulting yield was
unfit for use (23 out of 45 bags). The following year the potatoes
from the experimental plot were planted in a paddock with un-
treated Brownell seed, to ascertain whether the effects of the
heating would extend to a second generation. During the growing
period there was a marked difference between the two lots of seed,
the plants in the heated plot being recognizable a mile away by
their regularity and vigour. The yield from the heated plot
amounted to 5-019 tons per acre as compared with 3-585 tons per
acre from the untreated controls. The adoption of the heating
process as a regular feature of seed-farm routine is advocated.
Estimating the average increase derived from heating at 1-5 tons of
_ potatoes per acre, there would be an annual increase of 42,000 tons
on the 1919-20 statistics. The heating process should supply an
easy and inexpensive means of controlling Irish blight | Phyto-
phthora infestans| which is readily destroyed by four hours’ ex-
posure to a temperature of 104° F. It may be calculated that one
acre of heated seed will produce enough seed for ten acres, the
average size of the crop on most Tasmanian farms.

THomas (P. H.). Annual Report of the Assistant Fruit Expert.—
Agric. & Stock Dept., Tasmania, Rept. for 1920-21, pp. 18-
19, 1922.

The results of spraying experiments on the Lord Wolsey variety
of apple, which was severely attacked by powdery mildew (Podo-
sphaera oxyacanthae), were very satisfactory, especially those
carried out with atomic sulphur. Considerable improvement was
also observed in the sections treated with iron sulphide. The
application of a manurial spray consisting of caustic soda and
nitrate of soda resulted in an increased yield.

WuerzEL (H. H.). Report of the Pathologist for the period 10th
June to 31st December 1921.— Repts. Bourd and Dept. of
Agric. Bermuda, 1921, pp. 80-64, 1922. [Received 1923.]

The loss from disease in Bermuda crops is stated to be probably
higher than in most other countries, owing to a combination of
a3

306

various factors favouring the development of pathogenic organisms.
Foremost among such factors is the continuous growing season,
the rainy winters being particularly favourable to nearly all
the disease-producing organisms. At a conservative estimate the
annual loss in Bermuda crops from diseases and pests (chiefly the
former) amounts to 50 per cent. In this report notes are given on
the diseases and pests observed by the writer, during the time he
spent in the island, to affect the more important crops, the latter
being arranged in alphabetical order.

In avocado pears continuous defoliation caused by a species of
Oidium resulted in an almost complete absence of fruit. Beans
were attacked by anthracnose (Colletotrichum lindemuthianwm),
blight (Bacteriwm phaseoli), Sclerotinia rot (S. libertiana),
powdery mildew (Hrysiphe polygoni), and mosaic. Black rot
(Bacterium campestre), frequently followed by soft rot (Bacillus
carotovorus), occurred on cabbage, turnips, kohlrabi, kale, and
other cruciferous plants. Sclerotinia rot was very. destructive to
cabbage. Celery was severely attacked by leaf blight (Septoria
petroselini var. apiz), black heart (believed to be due to an excessive
use of fertilizers containing soda and kainit), and damping off
(Pythium sp.?). In lettuce heavy losses were caused by drop
(Sclerotinia libertiana), which also attacked endive. A peculiar
lettuce disease known as ‘stunt’, which has recently also attracted
attention in the northern United States, was observed. The
affected plants are stunted and produce only a few long, weak
leaves, with a reddish or white discoloration according to the
variety. The disease is caused by a species of Pythiwm, and can
probably be controlled by disinfecting the soil of seed-beds, In
Bermuda infection appears to occur in the seedlings before trans-
planting.

Lilies suffered severely from stump rot, due to a species of
Phytophthora, which attacks the bulbs just as the shoots are begin-
ning to come through the soil, or shortly after. The entire stalk
may be destroyed, or only the growing tip may be killed, leaving
a stump with a rosette of leaves. The fungus inhabits the soil, and
spores produced on the surface are splashed by rain into the crowns
of the plants. Spraying with Bordeaux mixture, dusting with
copper-lime, or disinfecting the soil with formalin are recommended,

Pink root (Fusarium malli) is at present the only important
disease of the Bermuda onion crop, though Peronospora schleident
is said to have caused considerable damage from time to time. In
the papaw [Carica papaya] the yellow leaf disease (Pucciniopsis
caricae) has been found to affect the development and ripening of
the fruit and to cause premature defoliation. Powdery mildew, due
to one of the Erysiphaceae, causes severe damage to papaw seedlings.
It may be controlled by the application of a sulphur dust. The few
peach trees left in the Colony are very susceptible to the rust
Tranzschelia punctata [Puccinia pruni-spinosae], which causes
continuous defoliation and prevents the setting of the fruit.

Potatoes are attacked by early and late blight (Alternaria solani
and Phytophthora infestans), leaf roll, mosaic, scab caused by
Actinomyces chromogenus [A. scabies], Fusarium stem end rot,
and wilt (fF. oxysporum). The writer states that the excellent

307

system of seed potato field inspection and the complete control of

imports of seed tubers maintained by the Bermuda Board of Agri-

culture probably gives the growers the best grade of seed potatoes,

as far as disease is concerned, of any similar group of potato
owers in the world.

Leaf blight (Septoria lycopersici) of tomatoes, which greatly
reduces the size and numbers of the fruit, may be controlled by the
frequent application of Bordeaux mixture with the addition of fish-
oil soap (3 lb. per 50 gallons).

Notes on numerous other diseases observed by the writer are
given.

Wateruouse (W. L.). On the production in Australia of the
aecidial stage of Puccinia graminis Pers.—Journ. & Proc.
R. Soc. New South Wales, lv, pp. 278-288, 1 pl., 1921 [1922].

The author gives a brief description of a set of experiments
carried out in 1921 at the Sydney University, in which he succeeded
in inoculating two plants of Berberis vulgaris with sporidia of
Puccinia graminis obtained from Wales. Inoculation of the same
two plants under similar conditions with viable teleutospores from
Glen Innes, New South Wales, also gave positive results. Previous
attempts to infect barberry in Australia appear to have failed,
though McAlpine used germinating teleutospores. In both the
author’s cases, spermogonia and aecidia were produced, and aecidio-
spores from the latter, inoculated on wheat, produced typical uredo-
sori. No marked difference was noticed in the aecidial stage
produced by the Australian and British material. These results,
although obtained in highly artificial conditions, show that Puccinia
graminis on wheat in Australia has not lost its power of producing
the aecidial stage on the barberry, as believed by various workers,
and the author concludes that the cultivation of barberry should be
discontinued in Australia, where no native species are known,
though several introduced species are grown as ornamental shrubs.

Howarp (A.), Howarp (GABRIELLE L. C.), & RHAMAN Kuan (A.).
The Wheats of Bihar and Orissa.—Memoirs Dept. Agric.
India, Bot. Ser., xii, 1, 20 pp., 1922.

In this paper, dealing with 122 of the unit species (agricultural
types) of wheat isolated by the authors since 1909 from the
province of Bihar and Orissa, India, is included an account of their
behaviour in regard to the three rusts which attack wheat at Pusa.
These are, in the order of their appearance, brown rust (Puccinia
triticina), yellow rust (P. glumarum), and black rust (P. graminis).
All the types belong to common wheat (7’riticwm vulgare), and they
can be grouped in twelve botanical varieties. In the same botanical
variety, agricultural types occur which differ more in their degree
of susceptibility to rust than in any other character. In several
instances, two types almost identical in field characters exhibited
great differences in resistance to brown rust. Some of the types,
particularly those belonging to the new variety nigricans, are very
resistant to all the three species of rust.

The bulk of the paper is a description of the characters of each
of the 122 types, in which the authors have adopted Eriksson’s
numerical notation for the degree of rust resistance.

308

Satmon (E. S.) & Wormatp (H.). A safe method of preventing
‘punt’ in Wheat.—Journ. Min. Agric., xxix, 8, pp. 722-728,
1922.

The authors, after calling attention to the prevalence of bunt in
certain parts of England, give examples showing that the tradi-
tional method of treatment by steeping the seed grain in copper
sulphate (10 per cent. is frequently used) may cause a reduction of
30 to 40 per cent. in the germination of the seed. The strongest
solution (2-5 per cent.) that their experiments showed could be used
without injury to germination does not satisfactorily control bunt,
over 5 per cent. of the crop being bunted in some trials. They,
therefore recommend that the copper sulphate treatment be
abandoned.

The use of dilute solutions of formalin is strongly recommended.
Tests with many strengths showed that 1 part formalin to 480
parts water (1 pint formalin to 60 galls. water) gives as good
control as the 1 in 320 (1 pint to 40 galls.) usually recommended.
At greater dilution than 1 in 480, formalin is less efficacious.

There is no injury to germination if the solution of 1 to 480 is
used by sprinkling it over the seed wheat at the rate of one gallon
to two bushels of seed, so that every grain is wetted but pools are
not allowed to form under the heap of grain. The treated seed
should be covered for four hours, not more, with sacks soaked in
the formalin solution, and then spread out to dry in a thin layer on
a dry clean floor, previously disinfected with formalin if it has been
used for untreated wheat. The dried seed should be put in
thoroughly disinfected sacks and sown as soon as possible.

Hopkins (E. F.). Wheat scab.— Missouri Agric. Exper. Stat. Bull.
197, p. 48, 1922.

In this Bulletin, which is the report of the Director for the year
ending 30th June 1922, is included a note by E. F. Hopkins giving
the results of further experiments on the effect of hydrogen-ion con-
centration on the wheat scab organism (Gibberella sawbinetiz) [see
this Review, i, p. 340]. These showed that the greater the hydro-
gen-ion concentration the greater the number of conidia produced
on potato agar plates. Seven of the fifty-one varieties of wheat
tested for resistance to scab during the year were altogether free
from the disease and five others showed only a trace of infection.

KULKARNI (G. 8.). The smut of Nachani or Ragi (Eleusine cora-
cana Gaertn.).— Ann. of Appl. Biol., ix, 3 and 4, pp. 184-186,
2 figs., 1922.

In 1918 the writer observed a smut of Nachani (Eleusine cora-
cana) in the Bombay Presidency, India. The smut sori develop
only in some of the grains in the head, either singly or grouped in
patches of varying size. They are round or occasionally elongated,
and occur in the ovary, projecting beyond the glumes, and often
exceeding the diameter of the normal grains by one to six times,
being 3 to 8 mm. in diameter when round, and 4 to 15 mm. in
length when elongated. When fresh they are green (or occasionally
pinkish) in colour, but on drying they turn chocolate-brown or
dirty black. On rupturing the membrane, to which the light colour

309

is due, a deep brown to black, powdery spore mass is found. The
dark brown spores are round, 6-6 to 12-1 in diameter, and with
spiny walls. They germinate readily in nutrient media, forming a
thick, hyaline, septate promycelium with freely budding, fusiform
sporidia,

In order to determine whether the disease was seed-borne, a
smnall quantity of Nachani grain was infected with the spores of
the smut and divided into two lots, one of which was treated with
2 per cent. copper sulphate solution for ten minutes. Smut
appeared on a few plants in the plot raised from infected seed,
while in the treated plot all were free from the disease. The smut
therefore appears to be carried by the seed and to be amenable to
treatment with copper sulphate.

No smut of this host having previously been recorded, the name
Ustilago eleusinis is proposed for the fungus, English and Latin
diagnoses being given.

Buraer (O. F.) & Gomme (W.). Black rot of Oranges.—Vlorida
Agric. Exper. Stat. Press Bull. 343, 2 pp., 1922.
Black rot of oranges (Alternaria citri) begins at the blossom end
of the fruit, and causes premature ripening. Underneath the
small brown spot on the rind at the blossom end, the tissues show
a brown, later greenish to black discoloration, which may extend
right through the fruit to the core. In advanced cases the spot at
the blossom end expands and turns dark green or black, by which
time the interior of the fruit is black and the cells beginning to
break down. This condition exists in the field (where it often
escapes detection), and also develops in transit.

The disease was first observed in 1902 on California navel
oranges, and during 1922 it was reported to occur on the varieties
Ruby Blood, Parson Brown, Pineapple, Jaffa, Tangerine, and
Valencia. The writers found from 5 to 25 per cent. of infection in
groves inspected in November 1922.

Infected fruit should be buried and late varieties, such as
Valencia, should be sprayed with 3-3-50 Bordeaux mixture with
oil, a coating of which at the blossom end acts as a preventive. The
crops should be shipped as soon as they are ripe.

SAMUEL (G.). On the control of the brown rot disease of Oranges.
—Journ. Dept. Agric. S, Australia, xxvi, 4, pp. 322-324, 1 fig.,
1922.

During 1922 the brown rot disease [Pythiacystis citrophthora]
caused considerable damage to oranges in the low-lying river
districts of South Australia. The severity of the disease was
probably largely due to the excessively heavy rainfall, and the
resulting epidemic has probably served to spread the disease to
places where it was unknown before.

Affected oranges, which usually drop prematurely, have a dull
brownish, rotten patch on one side, which gradually spreads until
the whole orange is a shrunken brown mass, with a characteristic
sickly sweet odour. The skin remains comparatively firm.
Oranges near the ground are more susceptible than those growing
higher up. In storage, even the most minute patches gradually

310

cause complete rotting, which may spread from the diseased oranges
to those in contact with them.

The disease may be controlled by removing and burning or
burying (with lime) all fallen oranges. The latter should not be
thrown into the rivers, as the organism can live in water. The
lower limbs of the trees should be pruned so that no foliage or fruit
touches the ground, and the surface of the soil should be frequently
cultivated during the spring and summer, especially under the trees.
Irrigation can best be effected by means of trenches, which must
afterwards be filled,up in order to keep the surface of the soil dry.
Spraying with Bordeaux mixture is a troublesome and expensive
process, which should not be necessary if the above measures are
carried out. It is absolutely essential that the soil be kept dry.

All oranges showing the slightest sign of brown rot should be
discarded at picking time if possible, or in any case before packing.
If the oranges require washing, copper sulphate (1 oz. in 60 galls.)
should be added to the water.

CAMPANILE (GIULIA). Ulteriori osservazioni sulla malattia delle
frutta di Mandarino dovuta a Cytosporina citriperda Camp.
{Further notes on the disease of Mandarin Oranges due to
Cytosporina citriperda Camp. |—Le Staz. Sperim. Agrarie Ital.,
ly, 10-12, pp. 497-502, 2 figs., 1922.

This disease of mandarin oranges, first described by the author
[see this Review, i, p. 426], has since been observed by Monte-
martini on material from Catania. According to this worker, the
mycelium of Cytosporina citriperda penetrates the epicarp without
leaving much trace, and reaches its full development only in the
endocarp and in the membrane of the segments, where alone it finds
favourable conditions. The depression and alteration of the over-
lying rind is regarded by him as a secondary phenomenon. The
present author has found, however, that during certain stages of
the disease a well-marked spot is formed without any corresponding
growth of an internal stroma, while the mesocarp underneath the
diseased area is invaded by the mycelium, which sends hyphae into
the glandular cavities. This can, she thinks, only be interpreted as
indicating that the alteration in the rind is not a secondary pheno-
menon in such cases, which, as already stated, include the first-
formed spot. The later spots may be produced by an outward
growth of the mycelium in the interior of the fruit. The first
spot, in many cases the only external sign of the disease, is believed
to represent the point of entry of the fungus.

Inoculation experiments showed that the disease can be caused
by placing a small piece of stroma with pycnidia on the unwounded
surface of fruit kept in a damp chamber. After fifteen days a
red spot of about 4 mm. diameter became visible underneath the
inoculum, and this rapidly increased to a size of 1 by 14cm. On
the spots the characteristic stroma developed and pyenidia were
subsequently formed on the epicarp. In a variant of this experi-
ment, where the moisture was provided by adding a drop of water
to the inoculum daily, the first spot to appear was a little below
the point of inoculation, but a normal spot afterwards developed

311

underneath the inoculum. The former was evidently caused by
spores washed down from the pyenidia.

A description of the cultural characters of the fungus is given.
On mandarin juice agar development is very rapid and pyenidium
formation starts after forty-eight hours. The pyenidia may be
found full of spores before their walls are completely formed. In
Petri dish cultures small, hemispherical pustules of a diameter of
2 mm. are formed after five days. They consist of masses of
hyphae, and contain numerous pycnidia provided with well-
developed black walls. The hyphae, olive-coloured at this stage,
are generally swollen in the vicinity of the septa, and anastomoses
are very frequent. During their growth the colonies become sur-
rounded with a grey-green halo consisting of aerial hyphae possess-
ing thin, whip-like, hyaline tips. After the formation of pycnidia
the hyphae unite in massive cordons, which gradually increase in
thickness and give the stroma its almost cartilaginous consistency.
The usual mode of fructification is by means of pycnidia, but in
certain circumstances endogenous, oval, slightly fuscous conidia,
measuring 3-5 by 2-3 « are formed, especially in the aerial hyphae.
The germination of these has not been observed. Perithecia were
not found. In material nearly a year old, some of the mandarin
oranges had been transformed into a pseudosclerotial mass, while in
others stromata were found only on the surface of the pulp, and the
rest of the fruit was literally filled with a white, cottony mycelium
which had taken the place of the dried pulp.

Bud-rot in Taveuni.—Agric. Circ. |Dept. of Agric., Fiji], iv, 4,
p. 57, 1922.

In connexion with the coco-nut bud rot regulations [see this
Review, i, p. 365], a tour of inspection of the coco-nut estates in
Taveuni was made by Mr. M. A. Forsyth in June 1922.

In his report he stated that bud rot of coco-nuts had appeared
throughout the island with more or less severity, most of the cases
being found among comparatively young trees growing at some
distance from the sea. Active measures are in progress to ex-
terminate the disease, the danger of which is fully recognized by
most of the European planters. Very little has been done, how-
ever, on the native-owned estates. Otherwise the health of the
coco-nuts on the whole is described as very satisfactory, particularly
as regards freedom from insect pests.

SpeareE (A. T.). Natural control of the Citrus mealybug in
Florida.— U.S. Dept. of Agric. Bull. 1117, 18 pp.,1 pl., 2 figs.,
1922.

The chief factor in the natural control of the citrus mealy bug
(Pseudococcus citri) in Florida is stated to be unquestionably the
fungus Entomophthora fumosa n. sp., first observed in 1920 at
Orlando. It appears to be closely related to Xmpusa lecanii, which
has been observed on Coccus viridis, a coffee pest in Java, but
differs in the possession of resting spores and in the characters of
the conidia. In some respects it also resembles mp. fresenii and
Emp. lageniformis, both aphid parasites. Hnt.fwmosa is regarded as

312

being as effective a control agent as the brown-tail moth fungus
Emp. aulicae.

The description of the fungus is as follows :—Conidia more or less
fusiform, 16 to 28 by 8 to 104, smoke-coloured, tapering rather
abruptly towards the base and apex, occasionally elliptical. Apex
sharply rounded, base or papilla weak but visible; conidiophores
simple, smoke-coloured, slender, arising directly from spherical,
yellowish, hyphal bodies. Secondary conidia elliptical, small, 4 by
8 yz, rather thick-walled, without papillae, arising on 1 to 5 slender,
capillary-like conidiophores from each primary conidium. Resting
spores (? zygospores) apparently arising from conjugation of hyphal
bodies, spherical, opaquely black, 15 ~ in diameter, provided with
a hyaline protuberance or appendage. When crushed the black
exospore cracks, revealing the internal, hyaline, spherical, thick-
walled spore. Host attached to substratum by insertion of pro-
boscis.

On Pseudococcus citri on Citrus spp., Florida; on P. citri on
Ficus sp., Louisiana ; on Phenacoccus sp. on Hibiscus sp., Louisiana.

The disease can be recognized at an early stage by the milky
white liquid which emerges from the bodies of crushed insects.
The so-called ‘hyphal bodies’ present in the liquid are spherical,
thin-walled, and filled with a finely granular protoplasmic content.
These bodies represent a vegetative stage of the fungus, and absorb
their nourishment primarily from the blood, additional food,
however, being furnished by the disintegration of other tissues.
Their reproduction is effected by a budding-off process. At first
the insect’s blood-circulation is slightly impeded and at a later
stage entirely inhibited. Finally the muscles and all other soft
tissues are destroyed and the interior of the body solidly filled by
the fungus.

The development of the conidia and resting spores, which are
formed after the death of the insect, is described in detail, the
former being the more common type of reproduction in Florida.
Germination of the resting spores has not been observed.

The results of investigations carried out in 1921 at Winter
Haven, where weekly collections of infested mealy bugs from
grapefruit were made between 13th June and 8th August, showed
that on the first date only 11 per cent. were destroyed, while in the
last collection 94 per cent. succumbed. There was a marked rise
in the percentage of mortality between 22nd and 29th June (18 to
64 per cent.).

The artificial control of citrus diseases in Florida by fungicides
and the natural control of injurious citrus insects by entomogenous
fungi are antagonistic. The results of experiments have shown
that, with the possible exception of lime-sulphur, all the fungicides
used (Bordeaux mixture, copper soap, barium tetrasulphide, &c.)
prevented the development of Hnt. fwmosa and thus facilitated an
unrestrained development of the mealy bug.

VOUKASSOVITCH (P.). Observations sur la Cochylis et l’Eudémis
faites 4 Monlon pendant l’hiver 1921-1922. | Observations
on Cochylis and Hudemis made at Monlon during the winter
1921-1922. |—Rev. zool. agric. et app, (Bordeaux), xi, 4 and 5,

313

pp. 61-66 and 74-78, 2 figs., 1922. [Abs. in Rev. Appl.
Entom., x, Ser. A, 12, p. 620, 1922].

During the observations made near Toulouse in the winter of
1921-1922, about 70 per cent. of the pupae of the vine moths
[Clysia ambiguella and Polychrosis botrana| were found to be
destroyed by the fungus Spicaria farinosa var. verticillowles, the
dry weather probably weakening the resistance of the insects. The
fungus was readily cultivated on glycerined potatoes in Roux
tubes and in nutritive G.S.P. medium (1 per cent. peptone, 5 per
cent. saccharose, 3 per cent. glucose, and 2 per cent. agar). At 22°
to 24° [C.] the mycelium develops very rapidly, the first fructifica-
tions appearing after 72 hours. At lower temperatures develop-
ment is slower and more irregular, and in such cases potatoes are
a better medium.

Reppy (C. 8.) & BrentzeL (W. E.). Investigations of heat canker
of Plax.—U.S. Dept. of Agric. Bull. 1120, 18 pp., 5 pl., 4 figs.,
1922.

The present paper isa report on the results of an investigation
started in 1916 by the United States Department of Agriculture, in
co-operation with the North Dakota Agricultural Experiment
Station, of a very destructive non-parasitic type of canker of flax
in the semi-arid regions of western North Dakota and eastern
Montana. Of the other known types of flax cankers, anthracnose
canker caused by Colletotrichum lini Bolley [which the authors
consider to be the same as C. linicolwm, the new name given by
Pethybridge and Lafferty because of the inadequate description of
the former fungus] was found, during a survey held in 1920, to be
widespread in the Michigan flax-growing districts; in a number of
cases flax beyond the seedling stage was attacked, and in some
instances as many as 60 per cent. of the plants showed girdling
connected with anthracnose lesions. The indications are that this
condition resulted from a combination of injuries caused by heat
and parasitic fungi, and that the area affected is determined more
by temperature with its resulting physiological effects on the cells
than by moisture, oxygen, or light relations. Anthracnose canker
seems to be rather rare in the United States during some years,
and, when present, the damage caused by it is confined almost
entirely to young seedlings.

The heat canker dealt with in this paper is non-parasitic in
origin. It causes severe losses and occurs to about the same extent
each year in the northern Great Plains area, in the latter half of
June and the first half of July. The chief symptom is the
destruction of the cortical tissues at or near the surface of the
ground. Plants under three inches in height are usually rapidly
killed; if the injury occurs later, when the plants are three to five
inches high, the latter fall over but generally continue to live for
some time, as their inner vascular system is not injured, Only in
rare instances are plants over five inches in height injured in this
Way ; numerous more mature specimens of heat-cankered flax can
be found, but in such cases growth continues after the initial injury.
Enlargement of the stem on the older plants occurs just above
(sometimes also below) the point of injury, at which point most of

314.

the cankered stems are sooner or later severed either by the wind
or by the action of saprophytes. Otherwise the plant dies when
the starving roots can no longer support the needs of the aerial
arts.

3 The evidence gathered from a number of field observations
pointed to the possibility of the trouble being caused by excessive
heat at soil level during the seedling stage. Field experiments,
details of which are given, were therefore carried out in the period
1917-1921 in North Dakota, the results of which may be summarized
as follows :—Heat canker developed mainly during or immediately
following very hot, sunny days, the temperature on the surface of
the soil reaching on some days 48° to 50°C. The young seedlings
under four inches in height are the most susceptible, and suscepti-
bility lessens with increasing maturity. Flax plants which have
developed under hot, dry conditions are less susceptible than more
succulent plants. Seedlings growing in a soil having a shallow
surface mulch over a firm seed bed are less liable to be cankered
than those in a soil with the surface compacted by rain, as the
crust thus formed brings the overheated surface soil in immediate
contact with the tender tissues of the succulent young flax stems.
The incidence of canker was greatly reduced in plots where partial
shading was secured either by sowing a thicker stand of flax or by
cereal nurse crops or weeds growing among the seedlings, while no
canker at all occurred in plants shaded by vertical strips of canvas
ten inches high. A condition very similar to heat canker was
artificially produced by chemical agents, such as concentrated
sulphuric acid, and by heated wires looped around individual plants.
Mention is also made of similar heat injuries to other plants
observed and described by various authors.

Promising control measures are thicker and earlier sowing,
while it is suggested that drilling the rows north and south instead
of east and west may prove helpful in lessening the severity
of this type of injury.

JOcHEMS (S. C.) & Maas (J. G. J. A.). Slijmziekte in de Hibiscus
cannabinus op Sumatra’s Oostkust. [Slime disease of
Hibiscus cannabinus on the east coast of Sumatra.|—Teys-
mannia, XXxil, 12, pp. 542-546, 1 fig., 1 diag., 1922.

Cases of slime disease (Bacillus solanacearum) having been
reported from the newly established plantations of Hibiscus
cannabinus on the east coast of Sumatra, a series of investigations
on this disease was instituted in August 1922 at the Deli Experi-
ment Station. The Hibiscus seedlings were planted on heavily
infested soil, formerly occupied by tobacco and other susceptible
plants such as Phaseolus radiatus, Ipomoea batatas, Crotalaria
striata, and Impatiens balsamina. Three rows of healthy Hibiscus
alternated with one row of healthy tobacco seedlings, the spacing
of the plants being closer in the case of the former. Ten days
after planting the Hisbiscus began to show signs of wilting, and at
the end of twenty-five days 68 per cent. of the seedlings were dead.
The tobacco plants were attacked by Sclerotiwm rolfsii and
? Pythiwm, as well as by B. solanacearum, but the Hibiscus did not
suffer from any other disease but that caused by the latter,

a

315

According to Miss Westerdijk (Meded. Deli Proefstat., x, p. 30,
1918) H. cannabinus is liable to be attacked by S. rolfsiz, but this
experiment indicates that it is, at any rate, highly resistant. After
forty days, 84-7 per cent. of the Hibiscus plants were diseased as
compared with 51-2 of the tobacco seedlings. Possibly the much
closer planting of the Hibiscus may partially account for its
greater susceptibility, infection spreading rapidly from the root
systems of diseased plants to the adjacent healthy ones.

The first symptom of slime disease of H. cannabinus is_ the
assumption of a horizontal position by the petioles, followed by
drooping of the leaves. As a rule all the leaves of a plant droop at
the same time. A further symptom generally noticeable the same
day is the curling of the leaves along the midribs, with the concave
sides uppermost. The next day the leaves are tightly furled and
hang straight down; soon afterwards they are quite withered.
Thus the whole course of the disease is much more rapid in

- Hibiscus than in tobacco.

Microscopic examination revealed no difference between the
characters of the attack in H. cwnnabinus and those in other plants
affected by slime disease. The causal organism was readily
isolated and cultured on bouillon-peptone-agar, typical colonies of
B. solanacearum being produced. Hibiscus and tobacco plants
inoculated with two-day-old cultures from tobacco rapidly
developed the symptoms of infection, and a few days later the
causal organism was re-isolated. The discoloration of the stems
was more noticeable in the tobacco plants on account of their
greater transparency. All the inoculated plants died in from eight
to fifteen days.

NisHimuRA (M.). Studies in Plasmopara haistedii.—Jowrn. Coll.
Agric. Hokkaido Imper. Uiiv. (Sapporo, Japan), xi, 3, pp. 185—
210, 6 pl. (1 col.), 7 figs., 1922.

In June 1918, the author observed that five sunflower (Helianthus
annuus) plants in a plot containing about one hundred, at Columbia
University in the United States, were infected by Plasmopara
halstedii, a brief historical account of which is given in this paper.
The diseased plants were stunted and showed well-marked light
and dark green areas, which gradually spread from the region of
the petiole all over the leaf, and were due to the spread of mycelium
coming from the stem. Young leaves, when the chlorosis occurred
along the main veins, usually became curled. An examination of
the diseased plants at various stages of development showed that
the fungus often originated in the underground portions and
spread into the aerial parts. In H, divaricatus, on the other hand,
infection takes place through the stomata and travels down the
stem to the rhizome, where it apparently becomes perennial.

Seeds from infected sunflower plants gave a low percentage of
germination but the seedlings did not show any signs of disease.
Seeds sown in soil from diseased plots showed 70 per cent. of
infection, the controls in healthy soil remaining unaffected. In
another test, sunflower seedlings, planted in moist soil inoculated
with the conidia of P. halstedii, became infected to the extent of
40 per cent., the control plants remaining healthy. Tests in which

316

the soil was inoculated with zoospores immediately before sowing
the seeds gave negative results.

Sunflower plants were naturally infected by P. halstedii in the
same fields in 1918, 1919, and 1920 successively. In order to
ascertain how the fungus overwintered, three lots of soil were
inoculated respectively with conidia collected from the leaves, with
mycelium which developed in young seedlings, and with oospores
collected from the tissue of the host plants. The soil in all three
cases was left exposed during the winter 1919-20, and sunflower
seeds were sown in it in the following spring. Infection occurred
only in the soil inoculated with oospores.

In the course of infection experiments it was observed that when
active zoospores were brought into contact with a sunflower root
in sterilized water, the zoospores came to rest on the root in one or
two hours. Some produced germ-tubes of varying lengths which
entered the roots and developed in the intercellular spaces. In
some cases the infection occurred where the root hairs had
broken off, but entry could also take place through the quite
uninjured epidermis.

The mycelium was found in the intercellular spaces of all the
tissues and, in young plants, even in the vessels. Diseased plants
develop fewer secondary roots. In numerous instances conidia
developed in the intercellular spaces of the spongy tissues, and in
the substomatal cavities of the leaves; also in the root and stem
tissues, especially following injury by insects or other agencies. In
fresh material the oogonia and antheridia are found scattered
through the root tissue. The former are large, globose bodies,
30 to 48 in diameter, the latter somewhat irregular in shape and
12 to 30 win diameter. Some of the short branches of the mycelium
swell at the end and become filled with a dense mass of protoplasm.
Oospores may also develop in the leaves and stem. Sunflower
seedlings infected with P. halstediz late in April showed a number
of oospores four to six weeks later, while in July and August the
sexual stage is less common. ‘The oospores are generally formed
most readily when the vitality of the host has declined. The
mature spores were often found just beneath the epidermis, the

“inner wall of which was ruptured by them.

The second part of the paper deals with a cytological investiga-

tion of the methods of fertilization and oospore formation.

WATERS (R.). Apple flesh-collapse or brown-heart. Some recent
investigational work.—Vew Zealand Journ. of Agric., xxv, 6,
pp. 334-3840, 1922.

Flesh-collapse, now known to be identical with the ‘ brown-heart’
of apples shipped from Australia and Tasmania |see this Review,
ii, p. 124], has been found to be much more prevalent among
mature fruit and may be largely avoided by selecting greener
apples for storage. This is, however, by no means the only factor
to be considered, since in cases observed by the author 12 per cent.
of even the least mature fruit were affected after five months’ cool
storage.

In 1922 flesh-collapse was first noted about the end of June,
rather less than three months after the fruit was placed in cool

317

storage, while in the two preceding years it was not observed until
September. The experience of certain growers indicates that fruit
held without cooling up to seven weeks after picking has sub-
sequently stood cool storage conditions better than that stored
immediately after gathering. The most difficult time to secure
control of cool storage conditions is during the first few weeks,
when some, at any rate, of the damage to the 1922 consignments
occurred.

Natural conditions of temperature and humidity in the Nelson
district admit of keeping Sturmer apples in suitable sheds until
August or September, after which time the fruit becomes liable to
shrivel on account of the lower relative humidity (averaging 82),
while in the cool stores the humidity is more often near the satura-
tion point. To be of practical value, cool storage during the period
until August or September should more completely arrest the
activities of the fruit than can be done in a shed; otherwise shed
storage during this period would be just as good. ‘The first
essential in accomplishing this is a lower atmospheric temperature
range, for the lower the temperature range in the apple-flesh
(within limits) the slower is the progress of the metabolic processes
in the fruit. It has been shown by statistics that the apple is
extremely tolerant of fluctuating temperatures, which are averaged
out by the fact that the flesh of the fruit heats and cools more
slowly than the surrounding atmosphere. Thus the average of the
mean monthly temperatures from May to September (47-8° F. at
Nelson in 1920) will correspond closely with that of the apple-
flesh temperature in the sheds. At this temperature the apples
ripen more rapidly than would permit of long storage and the mean
apple-flesh temperature in cool stores must therefore be kept con-
siderably below 47-8° if it is desired to secure successful storage for
seven or more months. The relative humidity must be over 82 in
order to prevent shrivelling, and a minimum temperature of the
atmosphere discharge from the cooling plant of 32° F., the plant
being run for twelve hours, is well on the safe side.

Discussing the technical details of cool storage, the author points
out that the only way to surmount the various difficulties that may
arise in bringing down the temperature of the stored mass of fruit
cases sufficiently quickly, removing the excess moisture, securing
adequate ventilation, and the like, is to increase the rate of circula-
tion of the air. The greater cooling and drying efficiency of the
plant thus secured will reduce the necessary hours of running and
leave an interval during which defrosting and ventilation can be
safely performed. These measures are particularly necessary in
the early part of the season, when flesh-collapse appears to be
initiated.

The maintenance of very even temperatures, which is the usual
policy in cool stores, appears in some cases to have led to increased
humidity and a decreased efficiency of ventilation. In considering
this question, attention must be paid to the temperature at three
separate positions—in the flesh of the apples, in the atmosphere
within the cases, and in the atmosphere of the storage chamber.
The longer the working hours the nearer will these three tempera-
tures be to one another, and the slower will be the diffusion between

318

the atmosphere of the case and that of the chamber. A reduction
in the number of working hours would result in greater differences
between the temperature of the case-atmosphere and the chamber-
atmosphere; hence there would be a quicker passage of the gaseous
and vaporous apple by-products out into the chamber-atmosphere,
where they become dispersed and are later disposed of by
ventilation.

WILTSHIRE (S. P.). Studies on the Apple canker fungus. ITI.
Canker infection of Apple trees through scab wounds.—A ii.
Appl. Biol., ix, 3 and 4, pp. 275-281, 1 pl., 1922.

Infection of the shoots by Venturia inaequalis occurs during the
autumn and winter following their growth. In the spring most of
these scab pustules are surrounded by a cork layer, and are subse-
quently completely cast off from the tree, leaving only a slight
roughness of the bark.

This course of events, however, is sometimes disturbed by the in-
vasion of the scab pustules by the canker fungus (Nectria galligena
Bres.), which develops so rapidly that an area about 5 mm. in
diameter is destroyed before phellogen formation can take place.
In the early stages the canker area is usually somewhat sunken,
there is no crack in the bark between healthy and diseased tissue,
and the scab infection can often be identified in the centre of the
scar. Subsequent phases of development are often characterized
by the formation of well-defined cracks at the edge of the infected
area and a slight swelling of the adjacent tissues. Unless the tree
is sufficiently vigorous to form a cork layer round such a scar
before the wood becomes infected, the fungus penetrates to the
deeper tissues, in which case the scar resembles a normal canker
produced by VV. galligena. The occurrence of this type of infection,
though less common than that of the leaf scar type previously
described [see this Review, i, p. 106], is probably as prevalent as
infection through woolly aphis galls.

Early in the autumn, when the scab pustules are still very small,
microscopic examination frequently reveals the presence of NW.
galligena established on the stroma of the scab fungus, where it
develops its characteristic conidial stage. It is somewhat difficult
to distinguish between the mycelia of the two fungi, but, generally
speaking, that of Venturia inaequalis appears dark and thick-
walled, while that of NV. galligena is hyaline and less robust.

As soon as the canker fungus has gained a firm hold on a scab
pustule, the struggle with: the tree then begins. The cork
layer referred to above is often a sufficient barrier, since the canker
fungus is not normally capable of penetrating cork, but it may not
be developed quickly enough to confine V. galligena to the outside
of the barrier. Furthermore, V. cnaequalis is normally able to
penetrate suberized tissue, especially at the edges of an infected
region, and when this occurs the ectria appears to follow the scab
fungus, and subsequently outgrows the latter. In such cases, the
Nectria hyphae grow inwards between the cells of the cortical
tissue, gradually forming strands of mycelium, which are frequently
found radiating from an infected scab pustule, and which are very
characteristic of this type of infection. V. galligena also appears

319

to secrete some enzymic substance, which is able to attack the ceil
walls of the cortical tissue in advance of its growth, the walls being
partially disorganized. This substance may be a potent factor in
overcoming the resistance of the host, for though previous experi-
ments indicated that the enzymes cannot pass through a well-
developed cork layer, such as is formed in the summer on growing
trees, infection through superficial wounds in the winter months
and on cut shoots, where cork formation may be imperfect, some-
times leads to penetration of the cortex.

Once the canker fungus has effected an entrance to the cortex it
develops rapidly in all directions, especially along the intercellular
spaces. The cells of the cortex in the neighbourhood divide rapidly,
and the intercellular spaces become more or less obliterated. This
new tissue soon becomes infected unless protected by a cork layer.
The host persists in its efforts to form a wound cork layer, especi-
ally in the region between the sclerenchymatous bundles of the
cortex, the growth stimulus sometimes being so strong that the
tissues become ruptured. A strong cork layer is ultimately formed
round the infected tissue, and later the concentric cracks in the
canker scar which are typical of the disease develop. The stem
sometimes becomes completely girdled, the whole of the shoot above
being killed.

The usual practice of spraying against scab in the spring does
not provide for the control of autumn infection as described
above. Possibly winter spraying immediately after defoliation
might prove effective.

CuNNINGHAM (G. H.). Coral-spot, Nectria cinnabarina (Tode)
Fries. A wound parasite of fruit-trees.— New Zealand Journ.
of Agric., xxv, 6, pp. 854-359, 7 figs., 1922.

Coral spot (Nectria cinnabarina), the symptoms and life history
of which are described and figured, caused considerable losses in
Central Otago in 1919, when hundreds of fruit trees, especially
apricots, were killed outright. In ordinary cases the effects of the
fungus in any one orchard are generally slight, but it may cause
quite a large reduction in output by destroying the fruiting
branches, especially where the trees have previously been injured
by frost or insects.

The following preventive measures are recommended: removal
of dead wood from the trees, burning of all prunings and other
rubbish, and trimming of all rough edges of wounds. Split
branches should be bound up or excised, and deep, narrow crevices
filled with grafting-wax or other suitable matrix. Gum-pockets
should be cut out, and all exposed surfaces coated with coal-tar.
“a wounds should be painted annually until they are closed by
callus.

LINE (J.), The parasitism of Nectria cinnabarina (coral spot)
with special reference to its action on Red Currant.—Tvuns.
Brit. Mycol. Soc., viii, 1-2, pp. 22-28, 1 pl., 1922.

After a short reference to the previous work on Nectria cinna-
barina, the ‘ coral spot’ fungus, well known on many broad leaved
trees and also on dead branches of red and black currant bushes in

320 .

England, the author describes the field observations and experiments
made by him in an endeavour to establish (a) to what extent the
fungus may be regarded as a parasite, particularly on the red
cur rant; (>) its normal way of infection and method of growth in
the host tissues ; and (c) whether any differences in power of infec-
tion could be detected between different strains of the fungus.

Both direct observations in nature and inoculation experiments
indicate that Vectria cinnabarina cannot establish itself directly in
healthy, uninjured tissues, but that it can do so occasionally when
introduced into a wound in certain woody plants, more readily in
the case of the lime and horse-chestnut than in the case of the red
currant. Its normal method of attacking the red currant is by
spread through the wood cells, from a dead portion on which it has
gained a footing, into the healthy wood. Infections made on
artificially killed side shoots led to the development of stromata on
these shoots in six weeks or more, and then—at least six months
after inoculation—the fungus worked its way into the main stem
and became established as a parasite. The harmful action of the
fungus is primarily due to its growth in the xylem elements, which
are blocked by the fungal hyphae, thus causing death of the living
cells above the infected area on account of water shortage. No ill
effects appear to be shown for some time by the leaves and flowers,
even when the stem bearing them is almost completely blocked by
the mycelium at a lower level; then they suddenly show signs of
wilting. It is therefore thought improbable that any toxic
substance is secreted by the fungus which can affect living cells in
advance of the hyphae.

The red currant (which is much more frequently attacked than
either the black currant or the gooseberry) is usually somewhat
heavily pruned, and furnishes a number of dead spurs each year.
These were observed to be the starting-points of the fungus in
the great majority of cases. The time of the actual invasion of the
main stem does not appear to be related to the time at which the
first infection took place. Older bushes suffer more severely from
the fungus than the younger and more vigorous bushes of the
same variety, but the indications were that in most cases, the fungus
had been growing for several years on the older bushes, before
death of branches occurred on a large scale. No differences in
power of infection or behaviour in culture were observed between
strains ef the fungus isolated from different sources. Further
work is being done in collecting evidence as to the resistance of
different varieties of the red currant to the fungus and as to the
effect of soil conditions.

CUNNINGHAM (G. H.). Leaf-rust, Puccinia pruni-spinosae Pers.
Its appearance, cause, and control.—New Zealand Journ. of
Agrvc., xxv, 5, pp. 271-277, 9 figs., 1922.

Leaf rust of stone fruit trees is common in New Zealand on the
leaves of nectarines, peaches, and plums, less so on almonds and
apricots, and rare on cherries. The aecidial stage of the causal
organism, Puccinia pruni-spinosae, occurs in New Zealand only
on the cultivated anemone.

The infection, which is more severe in wet seasons, first becomes

321

noticeable on the leaves towards the end of December. Small
yellow areas, in the centre of which are rusty-brown masses of
uredospores, are formed on the under side of the leaf. Partial or
total defoliation follows, and when infection persists for several
seasons the trees become very susceptible to the attacks of silver
blight [Sterewm purpwreum|], brown rot [Sclerotinia cinerea], and
other parasitic diseases. Small, circular, depressed spots are formed
on the fruit, uredosori being visible in the reddish borders as
maturity approaches. Diseased fruit is frequently so disfigured as
to be unsaleable. Leaf rust forms small cankered areas on the
shoots of certain peach varieties, the bark splitting longitudinally
and the uredosori occupying the crevices.

The life history of P. pruni-spinosae is described. Teleutospores
are stated to be comparatively rare in New Zealand, except on
plums. In view of the limited distribution of anemones in the
Dominion, the overwintering of the fungus is thought to be effected
mainly by means of the uredospores.

In a note on the control of ieaf rust, by J. A. Campbell, the
following spraying schedule is recommended: (1) when the buds
begin to swell, 5-4—50 Bordeaux or 1-15 lime-sulphur: (2) one
month after petal-fall, 1-120 lime-sulphur ; (3) when the fruits are
half-grown, 1-120 lime-sulphur ; (4) shortly before the fruits reach
maturity, 1-120 lime-sulphur; (5) shortly after the fruit has been
picked, 1-120 lime-sulphur. The final application may require
repetition one or more times.

Deep ploughing and careful turning over of the soil to bury in-
fected leaves are essential.

Pope (W. T.). Avocado die-back.— Rept. Hawaii Agric. Exper.
Stat., 1921, p. 12, 1922.

Serious losses have been caused by die-back of avocados, which
generally sets in about the time the young trees first come into
bearing. The principal symptoms are the wilting, brown discolora-
tion and final dying back of branches, yellowing of the leaves, life-
less appearance of the roots,and the frequent sudden death of trees
when laden with fruit. The disease has also been reported to occur
on Tahiti and other Pacific Islands.

Mild forms of die-back may be controlled to some extent by
pruning out the dead parts of the top and applying plentiful
quantities of thoroughly rotted farmyard manure and water to the
roots. The disease is believed to be due to a variety of physio-
logical causes, such as defective drainage, an excess of volcanic sand
or a layer of rock, or an inadequate water supply. The principal
losses occur during the dry summer weather.

CARLETON (M. A.). Note on the Fusarium wilt disease of Bananas.
—WScience, N.S., lvi, 1,458, pp. 663-664, 1922.

Referring to Gaumann’s paper on a vascular disease of the
banana in the Dutch East Indies [see this Review, i, 7, p. 223], the
author states that while working with the United Fruit Company
in Panama he conducted an outdoor pot inoculation experiment on
the same lines as that made by Brandes with Fusarium cubense

322

(Phytopath., ix, 9, p..339, 1919), except that the Gros Michel variety
was used instead of the Chamalucco.

On Ist November 1921, the soil in fourteen pots was sterilized
by means of steaming for two hours at 110°C. Six pots were
neither sterilized nor inoculated. All the pots were planted with
one ‘bit’ of a banana having two ‘eyes’, and seven of those
sterilized were inoculated with F. cwbhense. The inoculum, which
was a combination of two cultures, one in cornmeal decoction and
the other in Uschinsky’s solution, was applied in the proportion of
about 1 litre per pot. By lst April 1922 all the inoculated plants
were diseased, most of them being severe cases. Up to 12th July
following, when the writer left Panama, none of the plants in the
uninoculated pots, sterilized or unsterilized, gave any indication of
the disease.

This experiment, which has the added interest of being carried
out in a different locality from that of Brandes, confirms the latter’s
conclusions that the destructive wilt or Panama disease is due to
F. cubense.

Informazione. [ Notes. |—Boll. mensile R. Staz. Pat. veg., ii, 7-9,
pp. 91-110, 1922.

In the ‘Coltivatore’ of 30th August 1922, Ciferri describes a
bacteriosis of olive twigs encountered in rather old and not very
flourishing trees in the province of Macerata. The disease is
marked by the withering and drying up of some of the young
branches, in which the cambium is found disorganized and turned
brown, the pith being also often partially disorganized. The
disease, which is quite distinct from the olive knot [caused by
Bacterium savastanot|, agrees with one described some ten years
ago by Montemartini, who named the organism to which it was
due Bacterium olivae. According to Ciferri this is a weak parasite,
incapable of penetrating unwounded tissues, or rather a saprophyte
which becomes parasitic when the host is in particularly unfavour-
able condition as, for instance, when it suffers from root disease.

MoreEtTTInNi (A.). Influenza dei trattamenti cuprici sulla pro-
duttivita del Frumento. [The influence of the treatment
with copper compounds on the productivity of Wheat.|—Le
Staz. Sperim. Agrarie Ital., lv, 7-9, pp. 264—277, 1922.

The author’s experiments, which are described in detail, indicate
that the treatment of seed grain of wheat with dry copper
carbonate or dry Caffaro powder results in an increased yield even
when no bunt [7%lettia tritici] is present. In his tests bunt-free
seed was used, and the treatments applied were respectively
immersion in water for 17 minutes, immersion in 0-5 per cent.
copper sulphate for 15 minutes followed by dipping in a lime bath
for two minutes, dusting with dry Caffaro powder used at the rate
of 3 parts of the powder to 1,000 parts of grain, and dusting with
dry copper carbonate in the same proportions. A fifth lot was
sown untreated as a control. All the seed was kept for 12 days
before sowing. No bunt appeared and the yield at harvest showed
the highest figures for the copper carbonate treatment; Caffaro
powder was next, then copper sulphate, water, and control in the

323

order named. These results are explained by the fungicidal action
of the copper compounds in preventing injury from the ordinary soil
fungi or those carried in on the grain, this beneficial effect being
counteracted in the case of the copper sulphate treatment by injury
to the embryo of the seed. A contributory cause may be that
the copper exercises a stimulatory action on the growth of the
plant.

Van Dituen (L. R.) & GanpDrup (J.). Een kleurmiddel voor des-
infectantia bij de behandeling van streepjeskanker. [A
colouring matter for disinfectants used in the treatment of
stripe canker. |—Arch. voor Rubbercultuur, vi, 1922. [Abs. in
Teysmannia, XXXIII, xi, pp. 526-527, 1922.]

For several years there has been an increasing demand for an
economical colouring matter for creoline, carbolineum plantarium,
izal, and the other disinfectants used in prophylactic treatment for
the control of stripe canker [Phytophthora] of Hevea rubber.
Indigo has been used to some extent, but besides being very
expensive it has the drawback of discolouring the manufactured
rubber.

In the present paper fuchsine, which colours the painted surface
a vivid red, is recommended. It causes no injury either to the
appearance or internal qualities of the rubber, and being much more
conspicuous than indigo or methylene blue, it affords an easy
method of detecting the treated trees. It does not interfere in any
way with the technical processes of rubber manufacture.

The writers used a Java preparation of fuchsine costing about 20
florins jabout £1. 14s.] per kg. For use with izal a concentration
of 0-5 per mille sufficed, while double that amount was required to
produce a good colour with creoline and treble with carbolineum
plantarium. The addition of fuchsine to a 5 per cent. solution of
creoline or carbolineum plantarium, the cost of which is about 5
cents [100 cents = 1 florin] per litre, would involve an additional
expenditure of 2 and 3 cents respectively.

RutH (W. A.). The effect of Bordeaux mixture upon the chloro-
phyll content of the primordial leaves of the common Bean,
Phaseolus vulgaris L.— Amer. Journ. of Bot., ix, 10, pp. 535—
550, 1922.

The fact that a number of plants show a distinctly greener
colour after being sprayed with Bordeaux mixture suggests that
spraying increases the chlorophyll content of the leaves. The
experiments described in this paper were devised for the investiga-
tion of this phenomenon.

Bean plants were grown under very carefully controlled con-
ditions in a greenhouse. The results were obtained from primordial
leaves only, which were measured and weighed in the fresh
condition and immediately dried in a rapid current of air at 45° to
50°C. The leaf areas were estimated by drawing the outline of
the leaf on paper and weighing the enclosed portion. As soon as
the leaves were crisp each lot was placed in a small tin box until
its chlorophyll content was determined. The latter was accom-
plished by colorimetric comparison of acetone extracts with an

324

extract standardized according to a method essentially the same as
that of Willstatter and Stoll (Untersuch. tiber Chlorophyll,
Methoden und Ergebnisse, Berlin, 1913).

Before determining the effect of spraying upon the chlorophyll
content, the degree of variation in the chlorophyll content which
took place as the plant grew was determined. Primordial leaves
at four ages were used for this purpose. During the period before
the cotyledons were shed, there was a marked increase in the
amount of chlorophyll per sq. cm., and an even more marked
increase per gram of fresh weight. From this period onwards,
there was a decrease in the amount of chlorophyll to the sq. em.
and per gram of fresh weight, which was associated with an
increase in the fresh weight of the leaf per sq. em. and a lessened
rate of increase in area. The necessity was recognized of com-
paring plants harvested only at the same stage of development.

The correlation between rapid growth and high chlorophyll
content was determined also by cutting off the growing buds above
the primordial leaves in order to increase the latter’s growth. A:
greater chlorophyll content per sq. em. was produced by this treat-
ment as compared with controls.

To determine the effect of Bordeaux on growth in length, one
half of the seedlings in each of five flats were sprayed as soon as
the primordial leaves unfolded. It was found that the relation of
the sprayed leaves to the unsprayed, 0, 2, 4, 8, and 14 days after
spraying, was 103, 97, 96, 96, and 95 to 100.

The effect of Bordeaux on the development of chlorophyll was
investigated by spraying one-half the plants in 3 flats as soon as
the primordial leaves had unfolded, and one-half the plants in
3 other flats when the cotyledons were dropping, 4 days later.
Three days after the latter spraying all the plants were harvested.
The average of the areas of sprayed and unsprayed leaves per flat
was 53-3 and 57-9 sq. em. respectively and the chlorophyll content
(mg. per sq. cm.) 0-00390 and 0-00361 respectively. The average
chlorophyll content per leaf of the sprayed and the unsprayed
leaves was practically the same.

The probable relations between photosynthesis and the increased
chlorophyll content are discussed, especially with regard to pub-
lished work on the subject, but experiments on this problem
are reserved for further work.

A bibliography of 42 titles is appended.

PIcHLER (F.) & W6peErR (A.). Bestrahlungsversuche mit ultravio-
lettem Licht, Rontgenstrahlen und Radium zur Bekampfung
von Pflanzenkrankheiten. [Radiation experiments with ultra-
violet rays, X rays and radium for the control of plant
diseases. |—Centralbl. fiir Bakt., Abt. ii, lvii, 14-17, pp. 319-327,
1922:

Experiments in the control of bunt of wheat (Tilletia tritici),
loose and covered smut of barley (Ustilago nuda and U. hordet),
loose smut of oats (U. avenae), and maize smut (U. zeae), by means
of exposure to ultra-violet rays and X rays proved very successful.
Exposure of the dry spores to ultra-violet rays inhibited germina-
tion more completely than when the spores were placed in tap

325

water, while germination was entirely suppressed when the spores
were exposed for 30 minutes to these rays in 0-1 per cent.
hydrochloric, sulphuric, or oxalic acid, or in 0-25 per cent. NaHSO,,
or 0-1 per cent. KClO,, or in a combination of 0-1 per cent.
H,SO,+0-1 per cent. KC]O,. The last mixture gave, on the whole,
the best results. Both oxygen and copper salts were activated
by ultra-violet rays, and showed enhanced fungicidal efficacy in the
presence of the latter. The action of solutions of colouring matters,
e.g. methylene blue or iodeosin, was also intensified by ultra-violet
rays. In field tests winter wheat seed severely infected by TY.
tritict was exposed to ultra-violet rays in a solution of 0-1 per
cent. KC1O,+0-1 per cent. H,SO, for 20 minutes, with the result
that the incidence of infection was reduced to 20 per cent. as
against 62 per cent. in the untreated controls.

Excellent results were obtained by the use of X rays, which have
the advantage over ultra-violet rays of penetrating the interior of
the plant, and are therefore more likely to be of use in such cases
as potato wart disease (Chrysophlyctis endobiotica) [Synchytriwm
endobioticum |. There was a slight retardation in germination
when bean and barley seed was exposed to X rays, but this dis-
appeared later on. As with the ultra-violet rays, treatment in the
acid solution H,SO,+ KCI1O, produced the best results in tests
made on bunt of wheat, loose smut of barley, and oat smut. Ex-
posure for one hour caused a slight reduction in germination in the
case of oats, but eliminated all the smuts, even that of barley which
is ordinarily only controllable by the hot water treatment. Ex-
posure in alkaline solutions was not nearly so successful.

Similar experiments with radium gave negative results.

JEwson (Stpyu T.) & TATTERSFIELD (F.). The infestation of fungus
cultures by mites (its nature and control together with some
remarks on the toxic properties of Pyridine).— Ann. of Ajyl.
Biol., ix, 3 and 4, pp. 213-240, 3 figs., 1922.

The infestation of fungus cultures by mites, especially by Alewro-
bius farinae and Tyroglyphus longior, is a source of considerable
annoyance in mycological laboratories. The authors’ experiments
showed that the mites can be controlled by exposing the cultures
to the vapours of pyridine, an exact description of the method
employed being given. In laboratory apparatus the pests can be
eliminated by the application of strong ammonia. Pyridine is shown
to have a slight toxic action on fungi, but in ordinary practice
this may be disregarded.

Informazione. | Notes.|— Boll. mensile R. Staz. Pat. veq., iii, 10-12,
pp. 125-150, 1922.

Notices of the following papers of interest are contained in this
number of the Lollettino.

Manzoni has published in the Coltivatore additional notes on the
leaf curl (‘incappucciamento’) of J'rifoliwm pratense [see this
Review i, p. a in which he states that the bacterium isolated by
him is evidently allied to one found in similar conditions by
Baccarini and Bargagli-Petrucci in 1914 and deseribed by them in
the Atti della R. Accad. dei Georgofili. The differences between the

326

two organisms are probably to be traced to the use of different
culture media.

Vaglio in the Italia vinicola ed agraria discusses the respective
merits of dry and wet fungicides for vines. In the author’s.com-
parative tests, sprayings with copper solutions have given the best
results as regards both Peronospora [Plasmopara viticola] control
and vegetative growth. The fungicidal dusts protected the grape
clusters well, but did not act as satisfactorily on the leaves. Sprays
are, therefore, recommended, wherever water is available, supple-
mented by sulphur and copper sulphate dustings for the better
protection of the fruit clusters.

The Stazione Chimico-agraria, of Udine, gives in the Rivista di
Ampelografia an account of experiments designed to control
simultaneously the downy and powdery mildews | Plasmopara
viticola and Uncinula necator| of the vine by the employment of
fungicidal dusts.. ‘Cuprosolfol’ has given results in this respect
which are not inferior to those obtained with sprays, but particulars
as to cost are wanting.

Ravaz, in the Progrés agricole et viticole, No. 45, recommends the
following treatment in cases of partial ‘apoplexy’ of the vine,
[caused by Fomes igniarius: see this Review, 1, p. 417] when, as is
not infrequently the case, only a branch is attacked. The latter is
removed, and, if possible, all affected wood is cut out, after which
a layer of tar is applied, or better still, all old and recent pruning
wounds are treated with an arsenical mixture. The following,
devised by Gauthier, is recommended: arsenious acid 15 kg.,
carbonate of soda 15 kg., soap 15 kg., water 65 litres. The
carbonate of soda is dissolved in the quantity of water indicated,
which is first warmed, and then the arsenic powder is added to the
still warm mixture which must be stirred with a wooden im-
plement. Finally, the soap is added. The latter is not strictly
necessary, and where arsenious acid is not available this can be
replaced by arsenite or arsenate of sodium. The mixture has to be
diluted with 10 to 12 times its volume of water before use.

RAYNER (M.C.). Mycorrhiza in Ericaceae.—Trans. Brit. Mycol.
Soc., viii, 1-2, pp. 61—66, 1922.

In the present critical review of H. Christoph’s paper on the
mycotrophic relations of the Ericales [see this Review, i, p. 129],
the author deals only with the part of her work concerning
seedlings of Calluna vulgaris, reserving the part relating to the
behaviour of cuttings pending the results of further experiments.
She maintains her conclusions that under the experimental con-
ditions described in her earlier paper [Ann. of Botany, xxix,
pp. 97-183, 1915] the development of Calluna seedlings is de-
pendent on infection by the mycorrhizal fungus and that such
infection takes place regularly from the testa of the seed at, or
subsequent to, germination. With regard to the results obtained
by Christoph, where unsterilized seeds sown on sterile peat pro-
duced, after six months, seedlings in all cases free from fungous
infection, with roots as vigorous as those of infected controls, the
author points out that until her claim that seed coat infection
occurs has been disproved, all seedlings raised from unsterilized

327

seed should be assumed to be liable to infection at. germination. It
is not always easy to observe infection in the clean roots of
seedlinys, and in the absence of opportunity to examine the
material it is only possible to suppose that the presence of mycelium
in the roots has been overlooked by Christoph. The same criticism
applies to his results obtained when sterilized seeds were sown on
sterilized soil, since no proof is given that the seeds were really
sterile. Similarly in the experiments in which sterilized seeds
were sown on unsterilized soil, no controls were sown on sterile
media and no proof of any kind is offered that the seeds were
adequately sterilized. If the soil used was from a Callwna station,
infection could obviously take place from such soil.

Further criticisms apply to Christoph’s failure to maintain his
cultures of sterilized seeds on sterilized soil under aseptic conditions,
as shown by a quotation from his paper mentioning the presence
in his cultures of mixed infection with species of Mucor and
Citromyces. Neither does the author consider Christoph to have
given satisfactory proof of the identity of the fungus isolated by
him from Calluna roots with the endophyte; so far as it is possible
to judge from his description of morphological characters, the
right organism was isolated, but the positive proof of identity can
only be supplied by inoculating into a pure culture seedling,
growing under controlled conditions, and observing the subsequent
production of mycorrhiza.

Another explanation of the discordant experimental results
recorded by Christoph may be found in the possibility of the
presence, in the sterilized peat used in his cultures, of an organic
substance capable of replacing the stimulus to development of the
seedling normally provided by the endophytic fungus, and this
question is now being fully investigated.

Perotti (R.) & Corrini-Comanpbucct (I.). Normale presenza di
batteri nelle radici di numerose Fanerogame. (|The normal
presence of bacteria in roots of numerous Phanerogams. ]—
Rend. Acc. Iincet, xxxi, ser. 5a, 2 sem., 10, pp. 484-487, 1922.

-In the roots of 75 per cent. of the normally developed phanero-
gamic plants examined by the authors, belonging to various non-
leguminous families which have up to now been considered
autotrophic, bacteria are found in such numbers that their presence
cannot be regarded as accidental. These organisms are distributed
throughout the cortex, and in some cases penetrate to the outer
zone of the bast, where they are found in the intercellular spaces.
At times their presence inside the cells has been detected.

Although it is not contended that these bacteria are necessary
for the development of the plant, their presence is not only not
harmful, but the state of growth of some specimens examined leads
to the belief that it is of advantage to the plant.

The methods of investigation are briefly described, and a list of
the plants examined is given. The organisms found in Diplotavis
erucoides and Calendula officinalis belong to several forms or
strains, generally oligonitrophilous, possessing characters which
might prove of value to the plants, whether green or not green,
with which they live in symbiosis.

328

Surcour (J. M. R.). Recherches sur la biologie du Phenix
dactylifera. Etude sur la culture, les maladies et les para-
sites du Palmier Dattier en Algérie (suite). [Investigations
into the biology of Phoenix dactylifera. Notes on the
cultivation, the diseases and parasites of the Date Palm in
Algeria (contd.).|—Bull. Soc. Hist. Nat. Afrique du Nord, xiii,
9, pp. 293-312, 1922.

This is an account of the cultivation of date palms in Algeria.
In the section devoted to pests and diseases it is stated that
‘baioud ’ or ‘ white’, a serious disease originating in Tafilalet, has
caused some damage in the Figuig district [see this Review, i, p.
18]. Palms affected with this trouble die rapidly, and the interior
tissues are found in a putrescent condition. According to investiga-
tions carried out by the Pasteur Institute at Algiers and by Maire,
the disease is spread by the irrigation water.

Another rapidly fatal disease was found to affect trees at Ain-
Srouna, in the Oued Rhirh. Nineteen young palms succumbed in
the space of a few days; their sap was decomposed and had
a strong vinous odour. Numerous saprophagous insects were found
inside the palms, but norie of them was responsible for the disease,
which came on while the trees were in full vigour and while their
roots were still actively functioning.

A disease, which affects the fruit only and is called by the natives
‘n’faroun ’, was observed by the author at Tolga and particularly
in the Oued Rhirh. It occurs towards September and is character-
ized by a marked browning of the dates, which become dull and
are finally covered with a whitish, pollen-like substance. This
modification is brought about by the drying of the epidermis,
which is raised in places, and may become flaky. The dates
become covered with spores and the ripening process is retarded,
the fruit drying up without acquiring the sweet flavour associated
with normal dates at maturity. The disease affects frequently
a whole garden, or even a palm grove, but the author has only
observed it on the ‘Deglet Nour’ variety, not on ‘ Ghars’, which
ripens earlier.

Brown (W.). Experiments on the growth of fungi on culture
media.—Ann. of Botany, xxxvii, 145, pp. 105-129, 7 figs.,
1923.

This paper deals with the so-called ‘ staling’ of fungal cultures,
By ‘stale culture’ is understood one which has ceased, or practically
ceased growing; a ‘stale medium’ is a medium which, through the
growth in it of an organism, has been made useless, or nearly so,
for further growth of the same or other organism. By ‘staling
substances or products’ are meant those metabolic products of the
organism which are responsible for slowing down or stopping its
growth.

” The general method of experimenting was based on observa-

tions of the rate of growth of colonies in Petri dishes, and was in

general similar to that more fully described in an earlier paper [see
this Review, ii, p. 24]. As a rule, the rate of spread of a fungal
colony increases to a maximum, then remains steady or slows down.

The higher the temperature, the sooner the maximum growth rate

329

is reached, at least in the case of some of the fungi tested. Fungi
which show no appreciable decline from the maximum are des-
cribed as being of the non-staling type, while those in which the
rate of growth falls subsequently are described as being of the
staling type. Periodical measurement of the diameter of the colony
enables these variations to be followed, the results being shown
in graphs. The fungi used were mainly Sphaeropsis malorum
and a species of Fusariwm, both of which show well-defined staling
phenomena.

The amount of staling shown by a particular organism varies
with the medium employed (being absent, for instance, when
Richards’s solution with agar was used) and is dependent upon the
amount of the particular medium present. In certain cases it can
be modified by slightly altering the conditions under which the
experiment is carried out. Thus a greater amount of staling was
shown by S. malorwm when grown on potato agar in closed Petri
dishes, than when it was grown on the same medium in open Petri
dishes placed in large 5- litre containers, the difference being pro-
duced by variations in the conditions of gaseous exchange in the
two cases. The same results are obtained with the Fusariwm, but
they are less marked asa rule. The reason of this behaviour was
shown to .be, ‘not the influence of the oxygen contained in the
- atmospheric column present in the case of the open dishes, but the
action of gaseous or volatile products of the metabolism of
the fungus, which in this case were found to be carbon dioxide and
ammonia. According to the extent to which these products
accumulate or are disposed of, the amount of staling varies. When
ammonia is in excess, the result is the accumulation of ammonium
carbonate and free ammonia in the medium, and this is. a more
actively staling combination than the ammonium bicarbonate that
forms when carbon dioxide is in excess.

Two main lines of experiment are described. ‘The first consisted
of exposing plates of fresh medium to the gases given off by fungal
cultures, after which the exposed plates were tested for staleness
by inoculating them with various fungi. The other method was to
grow fungal colonies in atmospheres which were controlled in
respect of their carbon dioxide ammonia content. In the first case
a batch of plates containing the same depth of the same medium
was inoculated with the fungus to be tested. When these cultures
had reached a certain age, a second batch of plates of the same
size, but without inoculation, was inverted over each culture of the
first batch, the lids being removed. After one or two days’ ex-
posure, all the plates of the second batch were removed and
inoculated with the same or another fungus and the growth in
a given time, usually two days, determined. The results showed
that a considerable amount of staling takes place in the medium in
exposed plates, but this effect soon disappears if the plates are left
for some time with the lids off before inoculation. Deep plates of
medium are more slowly staled than shallow plates of the same
medium.

In the second series of experiments, the amounts of ammonia
generated in Sphaeropsis cultures on a number of media were
determined, and experiments were carried out to show how far the

330

ammonia given off by a fungus is responsible for slowing down the
growth of the fungus itself, and what part the carbon dioxide of
respiration takes in the staling process. The results indicate that
the growth of Sphaeropsis (on a medium from which ammonia is
evolved) is improved (a) by any treatment which causes dilution of
the ammonia or its removal; (b) by allowing the accumulation
(within limits) of the carbon dioxide of respiration. Over soda,
which keeps the carbon dioxide concentration down to practically
zero, growth is least: over water, where under the experimental
conditions a concentration of about 2 per cent. carbon dioxide may
be reached, intermediate growth occurs, while it is best of all in
5 per cent. carbon dioxide. The last statement applies equally well
to Fusarium, but statement (a) to a less degree. The products of
fungal growth either diffuse outwards beyond the limits of the
growing margin or, as in the case of ammonia, pass into the
atmosphere of the culture and from there are re-absorbed by
the medium ; as a result the portion of the medium on which the
growing margin is advancing becomes daily less suitable for fungal
growth and staling of the margin begins.

Ammonia is not the only factor, or even the only alkaline factor, re-
sponsible for staling. The formation of fixed alkali is more marked
in the case of Fusariwm than of Sphaeropsis. With the latter
fungus, diminutions of the ammonia factor brought aboutimproved .
growth to a larger extent than with Fusariwm, where removal of
ammonia had to be accompanied by the raising of the carbon dioxide
concentration in the atmosphere of the colony to produce a distinct
effect on growth. In Sphaeropsis the volatile alkali is the more
effective staling substance, whereas in Fusariwm the converse is
the case.

The fact referred to in the earlier paper [see this Review, ii, p. 25],
that certain organisms show more growth after a time in a
moderate concentration of carbon dioxide than in air, is correlated
with the production by them of an alkaline staling reaction in the
medium. In such cases carbon dioxide, which at the concentrations
employed (10 to 20 per cent.) must be regarded as normally a re-
tarder of growth, produces the opposite effect because of its
neutralizing action on the staling products.

A correlation between staling and sporulation, and between staling
and the conditions governing intermingling of fungal colonies, was
obtained. The failure of two expanding colonies to unite, so often
observed in plate cultures, is interpreted as being due to a con-
centration of staling products in the intervening zone of the
medium. The relation of staling to sporulation is considered to be
probably very complex.

Funke (G. L.). Researches on the formation of diastase by
Aspergillus niger van Tieghem.—Rec. trav. botan. néerl., xix,
pp. 219-275, 14 graphs, 1922.

This paper contains details of an elaborate series of investigations
on the production of diastase by Aspergillus niger, especially on
the amount produced at different intervals of time and the influence
of the medium on enzyme formation.

In determining these points the importance of ascertaining the

331

optimum hydrogen-ion concentration is emphasized. With A. niger
the optimum range is wide (about P,, 5-8 to 3-8), and the organism
itself produces sufficient acidity in the standard cultures used to
ensure the necessary concentration. The origin of the conidia used
for making the test cultures is also important, marked differences
in the amount of diastase formed, and other characters appearing
when conidia from cultures grown on different media were used.
The author recommends the use of conidia grown for two genera-
tions on a medium of the same composition as the test cultures.

The results of the tests showed that A. niger produces large
quantities of diastase when cultivated on a standard mineral nu-
trient solution with the addition of starch, glucose, or maltose, from
about two or three days after inoculation, until a certain maximum
amount has been produced, after which no more is secreted during
the remaining lifetime of the fungus. The amount produced does
not vary according as starch or glucose is present in the culture
medium, and though the substitution of maltose delayed the pro-
duction of diastase, the ultimate total produced was probably the
same. The concentration of these substances used is also without
apparent effect on the total production of amylase, though higher
concentrations than 1 per cent. caused temporary disturbances in
enzyme formation, due apparently to the production of substances
which inhibit the action of the enzyme. These substances, how-
ever, disappear during the course of development, and are without
influence on the total amylase ultimately produced.

The diastase formed by A. niger is secreted into the culture
medium as soon as it is produced, and it may be kept for a long
period without losing strength.

The substitution of saccharose for the other carbohydrates men-
tioned above resulted in a great decrease in amylase production,
except when very low concentrations (e.g. 1 per cent.) were used.
In the latter case the amount was almost as great eventually as
with 1 per cent. glucose, but amylase formation did not become
considerable until all the saccharose was hydrolysed, and the invert
sugar assimilated. Grown on 5 per cent. glycerine, the fungus pro-
duced no diastase. On lactose there was no growth, as A. niger
seems to be unable to form lactase.

PRIESTLEY (J. H.). The toxic action of traces of coal gas upon
plants.— Ai. of Appl. Biol., ix, 2, pp. 146-155, 1922.

The very deleterious effects upon vegetation produced under
certain conditions by small quantities of unburnt coal gas are
obviously of considerable economic importance. While in Germany
and in the United States these effects have frequently been under
investigation, they have received less attention in Britain, possibly
owing to the general differences in composition between the
illuminating gases employed, but a change in the general methods
of coal carbonization could at any time so alter the average com-
position of British coal gas that the subject might become important
to horticulture.

The literature contains clear evidence that the poisoning effect of
traces of illuminating gas on plants is due to the presence of
gaseous, unsaturated hydrocarbons. It has been found that a

332

concentration of one-part of ethylene in ten million of air is toxic to
the etiolated epicotyl of a pea, retarding its growth, whilst a con-
centration of four parts in ten million will produce retardation of
growth, increase of girth, and a diageotropic curvature. The effects
of gas on superficial cor ky tissues have been frequently noted, pro-
liferation of lenticel tissue and other abnormalities being produced.
The proportion of unsaturated hydrocarbons present in illuminating
gas in Germany is very high, and in America, where water gas is
the illuminant, it is also usually higher than in Britain, but even
with the illuminating gas at Leeds, where the observations were
made, which contains a relatively small concentration of ethylene
(about 2 per cent.), it is very easy to obtain the full effect on
etiolated seedlings grown in a laboratory where gas is frequently
used, and experimentally it can be induced without any difficulty.
In many plants grown under etiolation conditions, the stem con-
tains a well-marked functional primary endodermis (composed of
an unbroken cylinder of cells in which the Casparian strip forms
a continuous network in the substance of both transverse and
longitudinal radial walls) from the base of the stem to just behind
the growing apex. On the stem of the same plant grown in the
light such an endodermis is only present for a very short distance
above the ground level. The formation of this structure is pre-
vented, when unsaturated hydrocarbons are present, by the in-
hibition of the normal accumulations of unsaturated fatty acids in
the region of the future Casparian strip. This accounts for the
sensitiveness of the etiolated epicotyl and the insensitiveness of the
normal stem in the same plant, where no functional endodermis is
present. It also explains the poisonous effect of traces of the gas
upon roots of higher plants, where a primary endodermis is always
present in the growing region. In the case of cork tissues the
suggestion is made that the gaseous, unsaturated hydrocarbons
arrest the normal deposit of fatty acids in the membrane of the
cork cells. The practical significance of these observations lies in
the fact that they afford a means of searching for definite diagnostic
features when plant injury is suspected to be due to gas poisoning.

Division of Botany, Department of Agriculture [Canada]. Survey
of the prevalence of plant diseases in the Dominion of
Canada, 1922. Potato disease section.—Third Ann. Rept.,
pp. 64-183, 1923. [Mimeographed.]

In the arrangement of data collected on the prevalence of potato
diseases, each province is separately dealt with, notes of a general
nature and a report from the Potato Certification Service being
furnished in every case except that of British Columbia, in which
the tabulated results are supplied by the Provincial Department of
Agriculture.

An examination of the tables shows that in British Columbia the
highest percentage of infection was due to blackleg (Bacdllus
solanisaprus) [B. atrosepticus], followed by mosaic and leaf roll.
In Alberta and Saskatchewan blackleg and mosaic were also very
prevalent, wilts (Fusarium oxysporum and Verticullium albo-
atrum) also causing severe losses in the former province. Leaf roll
was responsible for the majority of rejected fields in Manitoba,

333

followed by mosaic and blackleg, while in northern Ontario the
highest percentage of disease was caused by mosaic, and in
southern Ontario by leaf roll. Mosaic was the most prevalent
disease in Quebec, New Brunswick, and Prince Edward Island, and
leaf roll in Nova Scotia.

Mann (H. H.) & Nacpurkar (S. D.). Further investigations of
the Fusarium blights of Potatoes in Western India.— Agric.
Journ. India, xvii, 6, pp. 567-576, 1922.

The investigations reported in this paper extend the results
already published [see this Review, i, p. 357]. In stored potatoes
the Fusariwm disease, which is one of the most serious potato
storage diseases in India, either completely destroys a large propor-
tion of the tubers by a dry rot, or may not be obvious externally
during the whole period of storage, and only shows when the potato
is cut open, as a brown ring rather like that which is found in the
bacterial ring disease of India [Bacillus solanacearum]. From the
latter it can, however, easily be distinguished by certain characters
which are detailed. It is not yet certain that the two forms of
Fusarium injury described are caused by a single species. Besides
the storage rot, a Fusariwm wilt also occurs in the field, but its
etiological relation to the rots is not known.

Contrary to the usual statements regarding this class of disease,
the soil was not found to be the chief agent in causing the wilt
disease, the use of previously infected seed proving to be the
main cause. Infection through the soil is less frequent, probably
because, as was found in a series of field experiments, the fungus
remains infective in the soil for only between nine and twelve
months. Infection by using an infected knife for cutting the setts,
or by watering the soil with a suspension of crushed infected
tubers, appeared to be much more difficult to secure. Tubers from
a crop infected with wilt are very subject to rot on storage. The
experiments on the storage rot would seem to indicate that the
disease rarely, if ever, passes from one tuber to another, even if
they are cut, while a large proportion of tubers attacked by the
caterpillar of the potato moth (Phthorimaea operculella) became in-
fected when placed in contact with tubers attacked with the dry
rot form; this emphasizes the necessity of fumigating all potatoes
ntended for seed before they are stored. The opinion held by
growers that potatoes affected with Musariwm dry rot germinate
more quickly than others was confirmed.

The effect of using Fusariwm-infected seed_is not always
obvious at the time of harvest, and it is only when the potatoes are
stored that the full effect is seen. Early harvesting is advisable in
the case of potatoes known to be affected with Fusariwm, as the
loss in storage increases rapidly if the plants are allowed to ripen
in the field. A high temperature considerably increases the rapidity
of Fusarium attack, both on the growing plants in the field, render-
ing impossible the cultivation of potatoes in the Deccan during the
hotter part of the year, and on the stored tubers. Hence if infection
is present in the seed, as it almost always is, or in the soil, the
choice of a cool season of the year for growing the crop, or a

334

lowering of the temperature in the store, will considerably reduce
the damage done by these fungi.

The authors believe that an effective control of the disease can
only be attained by the development of pedigree strains of potato
free from Fusariwm infection.

CrépPIN (C.). Une maladie grave de la Pomme de terre dans le

Forez. [A serious Potato disease in the Forez district. |— Bull.

Soc. de Path. Vég. de France, 1x, 4, pp. 237-2438, 2 figs., 1922.

The observations on potato ‘dartrose’ (Vermicularia varians)

recorded in this paper have already been fully noticed [see this

Review, ii, p. 27]. Ditterent stages of the so-called ‘flaccid leaf

roll’, which appears to be one of its most marked symptoms, are
figured.

Fox (E.). La dartrose de la Pomme de terre en 1922. [Potato
‘dartrose’ in 1922.]—Bull. Soc. de Path. Vég. de France, ix, 4,
pp. 244-250, 1922.

The author summarizes the information obtained at the Station
de Pathologie Végétale in Paris regarding the outbreak of this
disease in France in 1922. The more important points have
already been noticed [see this Review, 11, p. 173]. None of the
specimens examined bore typical fructifications of Vermicularia
varians, but the author believes that this fungus was the cause of
the disease.

TispALE(W. T.) Seedling blight and stack-burn of Rice and the
hot-water seed treatment.—U.S. Dept. of Agric. Bull. 1116,
11 pp., 6 pl., 2 figs., 1922.

In the southern parts of the United States heavy annual losses
in, the rice crop are caused by the staining and decay of the grain
in the shock and in storage, and by poor germination of the seed.
The staining, which is also known as ‘stack-burn’ and ‘ flecking’,
resembles the trouble familiar to the European rice trade as ‘ yellow

grains’, the latter, however, being caused by a different fungus.

(Protoascus colorans). During the author's investigations of rice
diseases conducted at Crowley, Louisiana, from 1919 to 1921, he
found that stack-burn seed injury was associated with a leaf spot
and seedling blight of rice. The leaf spot is caused by the small
sclerotial fungus mentioned by Godfrey, who found it to be the
cause of a seedling blight (Phytopath., vi, p. 97, 1916, & x, p. 242,
1920). The present investigations show that the much more
important staining and decay of rice after harvest is due to this
fungus and to certain other forms which are mentioned. Amongst
the latter are two of the common rice parasites, Helminthosporvwm
and Piricularia, besides several ordinarily saprophytic species of
Epicoccum, Penicillium, Aspergillus, and Fusariwi.

The development of the disease is favoured by the humid atmo-
sphere and high temperatures of the South, and also by storage of
the rice in damp places or transport in warm, damp cars for con-
siderable distances. The spores of the fungi mentioned above
probably lodge between the glumes at flowering time and the
infection spreads if the rice remains stacked under warm, moist

—~ _-— = os

335

conditions. The sclerotial fungus, which has no spores so far as is
known, forms sclerotia in the glumes and on the surface of the
kernels, the latter becoming either shrivelled and brittle or, under
very humid conditions, much enlarged, irregular in shape, and
black in colour. In the presence of the other fungi mentioned,
the kernels have brown flecks and the decayed tissue is of a uniform
brownish colour. Dark bands of sclerotial tissue may be seen on
kernels infected with the sclerotial fungus.

On the whole, the drier and cooler climate of California is not
conducive to the development of the injury described above, but a
particular type of kernel flecking, apparently due to a species of
Alternaria, occurs there. An Alternaria was also found to be
constantly associated with a leaf spot of seedlings in Louisiana, and
an Alternaria leaf spot of black Italian rice and of C.I. No. 1564
has been found near Los Angeles but the fungus was not definitely
identified with the form on the flecked kernels.

Experiments in seed treatment showed that surface sterilization
was of no value in checking seed injury. The best method was
found to be immersion of the seed in hot water (54°C.) for 15
minutes, preceded by pre-soaking in tepid water for about 16 hours.
Honduras rice, a good commercial variety but very susceptible to
attack by internal seed fungi, was used in these tests. Seed from
California germinated better than that of the Louisiana varieties,
the internal fungi prevalent in the latter State being believed to be
responsible for the difference. Hot water prevents the further
development of the fungi in the seed, provided the latter is sown in
clean soil. This form of treatment, however, is thought to be too
laborious and expensive for general adoption, and it is hoped that
some process may be devised of drying under temperatures that
would kill the fungi and not injure the grain. The most promising
solution of the difficulty, however, appears to lie in the eventual
development of resistant strains and varieties.

STELL (F.). Some common diseases of kitchen garden crops.—
Proc. Agric. Soc. Trinidad and Tobago, xxii, 11, pp. 779-785,
1922.

A brief popular account is given of the causes and symptoms of
various diseases of vegetable crops likely to be met with in kitchen
gardens, together with elementary directions for their control.
The following diseases are discussed :—damping off of seedlings,
cabbage yellows caused by Fusarium [conglutinans], blight of
cabbage, beans, tomatoes, &c., caused by species of Rhizoctonia, soft
rot of cabbage [ Bacillus carotovorus|, downy mildew (Peronospora
pee eitioa)) and powdery mildew (Lrysiphe sp.) of cabbage, black
eaf spot of cabbage caused by Alternaria [brassicae], anthracnose
of beans [Colletotrichum lindemuthianuwm), leaf mould disease of
tomatoes (Cladosporium fulvwm), and blossom-end rot of tomatoes.

Polizeiverordnung zur Bekampfung des Kartoffelkrebses. a
regulations for combating Potato wart disease. |—Nachrichtenbl.
deutsch. Pflanzenschutzdienst, ii, 12, pp. 102-104, 1922.

This new potato wart disease order, issued by the Minister of

Agriculture on 27th September 1922, is an amendment of that

336

dating from 18th February 1918, and applies to the entire State of
Prussia.

Potato fields and stored potatoes are liable to inspection, with
a view to the control of wart disease [Synchytrium endobioticum],
by the local police authorities and officials of the plant protection
headquarters. The inspectors are authorized to remove suspected
tubers, &c., for examination. Owners or occupiers of ground and
stores observing symptoms of wart disease (described in an
appendix), on growing or stored potatoes are required to notify,
within 24 hours, the police or local authorities, who in their turn
must immediately inform the plant protection headquarters. The
decision of the latter or their representatives is final.

The refuse of plants growing in infested fields must be collected
and burnt, or buried at least half a metre deep where burning is
impossible. Potatoes harvested from infested fields must neither
be used for seed nor removed from their place of growth without
permission from the police issued on approval by the plant pro-
tection headquarters. They can only be used for fodder when
cooked or steamed. The residue from such potatoes must also be
burnt. Where factories for the preparation of potato products
are near by, it is best to hand over the tubers from con-
taminated fields to such factories, but any unnecessary movement
of the tubers is to be avoided on account of the danger of trans-
mitting infection in particles of soil adhering to them.

Only the potato varieties specially authorized by the local police
authorities may be cultivated in infected fields until further notice.
The only varieties admissible for this purpose are those listed as
immune from wart disease in the annual circular of the Biological
Institute. Seed potatoes are to be procured only from fields
approved by a Chamber of Agriculture, the Potato Cultivation
Society, the German Farmers’ Association, or the National Agri-
cultural Federation. Stable manure, ete., must not be sold by, or
otherwise distributed from, infected farms. Cellars and other rooms
employed for the storage of diseased potatoes must be disinfected
with milk of lime after use.

The above regulations do not apply to official Experiment
Stations, scientific research purposes, or the removal of samples by
the inspection authorities.

In case there is ground for suspicion that the infection has been,
or is likely to be, transmitted to other fields, the above regulations
may be applied to all the fields within an area to be defined by the
police authorities in accordance with the finding of the plant pro-
tection headquarters.

If infected potatoes are found elsewhere than on agricultural
premises the stock must also be rendered harmless or disposed of
for manufacturing purposes under the supervision of the local police
authorities.

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

APPLIED MYCOLOGY

Vou. II AUGUST 1923

SHARPLES (A.). Preliminary and detailed reports on ‘ black fruit’
disease of Pepper vines in Sarawak.—(ovt. Print. Office,
Kuching, Sarawak, 15 pp., 1922

This pamphlet contains a brief inane report on a serious
disease of Piper nigrwm, which the writer was invited to investi-

ate by the Rajah of Sarawak, followed by a more detailed account
of the state of pepper cultivation in Sarawak and the general
characters of the disease. The latter is regarded as being primarily
due to the attacks of the alga Cephalewros * mycordea, already known
to cause’ serious diseases of tea and clov es, and less fully studied
diseases of several other cultivated plants.

On pepper, the alga is practically confined to the fruit. It is
difficult to find any trace of it on young vines up to the time of
flowering (14 to 2 years), and even after the fruit disease is well
established the organism is seldom found on the leaves and stems,
although in one case the petioles were attacked. After the berries
form, those at the free end of the spike turn black, shrivel, and
may fall off. At the same time the remaining, practically ripe
berries show small, black spots from which arise the fruiting stalks
of Cephaleuros. In the final stage all the berries are involved;
most fall to the ground, but a few remain in a mummified condition
attached to the blackened spike. From these mummies a strong
growth of the alga can be obtained under suitable conditions. The
writer is strongly inclined’ to the view that C. mycoidea is respon-
sible for the whole of the symptoms observed.

The damage caused by this disease is very severe, and it has been
one of the main causes of the serious fall in the pepper exports for
Sarawak within the past ten or fifteen years. For its control
spraying does not seem a promising line of attack on account of
local ditticulties. Much of the trouble is due to the system of
abandoning the pepper gardens after a time and moving to a new
ared, leaving the abandoned plants 4 prey to parasites and a menace
to other gardens in the vicinity. Measures to check this practice,
and also to enforce removal of the old plants when it cannot be

H

338

prevented, are strongly recommended. The absence of any
machinery to ensure that the gardens are properly cared for is
emphasized, and the need for some form of agricultural organization
in the State pointed out. s

Fawcett (G. L.). Enfermedades de la Cana de Azucar en
Tucuman. [Diseases of Sugar-cane in Tucuman. |— Rev. Indust.
y Agric. de Tucumédn, xiii, 1-2, pp. 1-46, 21 figs., 1922.

In this paper the chief diseases affecting sugar-cane in the pro-
vince of Tucumén, Argentina, are described and an account is given
of the author’s own researches in regard to them,

Top rot or ‘ polvillo’ affects chiefly plant-cane, the proportion of
which to the whole crop is small. Reddish stains appear on the
sheaths, and streaks of the same colour on the leaves. Later the
two or three most recently formed leaves’ dry up and the.apical
shoot can be easily pulled out. The interior leaves and sheaths are
rotten and surrounded by a thickish, evil-smelling liquid. At times
the pressure of the growing apical shoot ruptures the sheaths where
they are weakened by putrefaction, and the shoot may then emerge
laterally. This condition, which is known in Java as ‘pokkah
bong’, occurs in cases where the sheaths are attacked while the
growing shoot is not yet affected.. Usually the latter is ultimately
involved in the rot.

The early stages of the disease are marked by the appearance of .

small translucent spots in the cylinder formed by the sheaths in
the apical bud. The spots may be only a few millimetres in
diameter and are covered with a watery exudation. Three bacteria
were isolated from such spots and named Bacillus flavidus n. sp.,
Bacillus D, and Bacillus F, respectively. All three are motile,
with peritrichous cilia, liquefy gelatine, and form acids on media
containing sugar. Bacillus D is Gram positive and generates no
gas on media containing sugar, while the others are Gram negative
and produce gas. Their other characters are tabulated and
described. Inoculations proved that all were capable of producing
top rot, B. flavidus being the most virulent. A high temperature
is necessary for successful infection, no success being obtained from
inoculations during the cool season (March—April). Rapidly grow-
ing cane is usually immune. Infection ordinarily results from
bacteria lodged with dust in the apical bud of the cane outside the
last three leaves to be formed, where the spaces usually hold water
and give organisms every chance to multiply.

Susceptible varieties include plant-cane of 213 POJ, plant-cane
and ratoons of 234 POJ, and a few other less important varieties.
Kavangire and 36 POJ are considered resistant, though the latter
may be attacked during its first year of growth. With regard to
the disease known as top rot in Java, the author thinks that
several different affections are included. No mention has been
made there of a reddish discoloration on the leaves, and the author
is of the opinion that the Argentine disease is distinct. Bacillus
vascularwm, to which top rot as well as gummosis has been attri-
buted by some writers, has not been found in Tucuman. Mésaic
probably predisposes the plants to ‘polvillo’ but chlorosis is not a
normal symptom of the latter, as stated by Spegazzini. Methods
of cultivation and irrigation have no influence on the disease.

—

339

Sngar-cane mosaic is common in the province but the affected
Javanese canes give good yields. Thick canes seem to suffer more
than thin, but the former are believed to be, in any case, unsuited
to the Argentine climate which is sub-tropigal. The so-called
Japanese canes, Kavangire, Zwinga, and Yon Tan San, are immune
but give too little sugar to be of value, while of the Java varieties
36 POJ is the most resistant and 213 POJ the least. Of other
varieties, D 1135 is almost as resistant as the Java canes. The
author reports having received cane affected with mosaic from

Brazil, though the disease does not appear to have been recorded in’

that country as yet. In Tucuman it is impossible to find a cane

quite free from mosaic, amongst the commonly cultivated kinds. .

Indications point to insect transmission of the infection, but the
species concerned has not yet been found. Aphids are not believed
to be responsible, at least not the species which the author has
found on diseased canes and which is believed to be A. sacchari.
Attempts to secure infection by juice inoculations failed, except
when carried out on the young leaves before they had emerged
from the bud, in which case 15 out of 21 in three different series
were successful.

In experiments on the control of the disease it was found that
neither fertilizers nor cultivation had any influence on it. Roguing
was also of no value, which is not surprising in view of the uni-
versal prevalence of infection. On the other hand, careful selection
of seed cane is stated to have given good results.

Rotting of sugar-cane setts after planting is a trouble character-
istic of sub-tropical countries, where the low temperatures after
planting may delay germination, Partially rotted setts may ger-
minate, but the shoots remain more or less stunted. Varieties differ
greatly in their lability to rot; Criolla, for instance, is susceptible,
especially the white strain, which usually dies out from this cause
in a few years, while the purple strain of this variety is less liable
to rot. The common Javanese varieties originally introduced are
very resistant, except 100 POJ and 139 POJ; Kavangire and
its allies are also resistant, but all the other varieties grown are
susceptible. Every year the gaps left by failure to germinate have
to be replanted in the case of the susceptible varieties, or the
variety would ultimately die out. In damp or badly-drained soils,
especially where nitre is present, even the resistant varieties suffer
from rot. Mosaic predisposes to this trouble in a marked degree.

Amongst the numerous fungi and bacteria isolated from rotted
setts, a list of which is given, the most virulent were found to be
Acrostalagmus glaucus n. sp., Cytosporu sacchari, Melanconiwm
sacchari, and a species of Iusarvwm. Several others, including
Acrostalagmus saccharin. sp.and some bacteria, can cause a certain
amount of damage.

Of frequent occurrence in the spring is a disease called ‘ yellows’,
in which the young shoots turn yellow or whitish. It is usually the
result of the sett rot described above, and is associated with a scanty
development of the roots. Similar conditions arise from drought,
and the presence of nitre in the soil. Sulphate of ammonia
counteracts the latter to a certain extent, but the use of resistant
varieties is the best preventive. The practice of ‘windrowing’

.
i a ee —

340

is stated to be productive of sett rot and yellows. Burning. the
trash on the fields as soon as -possible after cutting the cane has
been shown by experiment to reduce the damage.

Melanconium sacchari has been said to cause a rind disease of
little importance in Tucuman. It is frequently associated in other
countries with the much more destructive red rot due to Colleto-
trichum falcatum, and the author thinks that the latter is the
usual primary cause of rind disease as described elsewhere, though
M. sacchari may sometimes directly attack enfeebled canes,

The ring spot due to Leptosphaeria sacchari appears to be of
recent introduction into Tucuman. Mosaic predispo8es to the
attacks of this fungus, which does little harm, as it is usually con-
fined to the older leaves of the thick varieties. The species
described under the same name by Spegazzini differs from that
here referred to in not causing spots and in other characters. A
Phyllosticta occurs on the same spots as the perithecial fungus, and
is believed by the author to be genetically related to the latter [see
also this Review, 1, p. 27 71].

A linear leaf spot is caused by Phyllosticta sacchari Speg., but is
not very common. It is restricted to chlorotic leaves and those
affected with mosaic, and is found at times on the large white or
yellow stripes which are characteristic of the broad leaves of
Criolla and other thick canes. These stripes are thought to be
identical with those described by Cobb as due to the attacks of
Mycosphaerella striatiformans, a fangus not known in Tucuman.
P. sacchari does very little damage, and appears to be found only
in the Argentine.

Root disease of the type usually attributed to the attacks of
Marasmius sacchari is present in Tucuman to a small extent. The
disease causes a rot of the young roots, which are at first marked
with red spots, then turn black, and later break down and decay.
The rot spreads along the roots to the old seed-piece from which
they have arisen. Affected clumps are malformed and stunted, and
owing to the destruction of a great part of the root system they
readily succumb to unfavourable conditions such as drought. The
author doubts whether Marasmius sacchari, or the species of
Rhizoctonia and Pythiwm to which the disease has been more
recently attributed [see this Review, i, pp. 102, 205, 313] are really
the primary cause of the rot; he thinks the latter is due more to
defective soil conditions such as a bad soil texture or water-logging.
He has observed that cane suffers from the disease in some of the
badly-drained soils in the south of the province in seasons of ex-
cessive rainfall. Elsewhere it is not common. WM. sacchari has not
been found.in Tucuman, though two saprophytic fungi rather like
it, Nuucoria suborbiculata and Omphulia saccharicola, have been
observed on the dead sheaths and bases of the clumps.

Amongst the common diseases of sugar-cane known in other
countries but not yet reported in Tucumén may be mentioned pine-
apple disease (Thielaviopsis paradoua), red-rot (Colletotrichum
faleatum), and gummosis (Bacillus vascularuwm). These diseases
are briefly described, as well as some others of more restricted dis-
tribution. Latin diagnoses, with figures, are given of the new
species Acrostalagmus glaucus and A. sacchari, and the Fusarium
found to be one of the causes of sett rot is briefly described.

341

GAUMANN (E.). Ueber die Gattung Kordyana Rac. [The genus Kor-
dyana Rac.|—Ann. Mycol., xx, 5-6, pp. 257-271, 7 figs., 1922.
Raciborski founded the genus Kordyana in 1900 with the
following chatacters. ‘ Parasitic fungi, related to Exobasidiwm and
Microstroma, with small, hemispherical hymenia protruding from
a small stroma in a stomatal cavity. The non-septate basidia each
-bear on the apex two sterigmata with oblong elliptical, hyaline,
smooth spores’. Of the two original species, the author transfers
one (K. pinangae) to a new genus, and to the other (K. tradescan-
tiae) he adds two new species, K. celebensis and K. polliae. The
host plants of all three are members of the Commelinaceae. As
revised the genus consists of parasitic Autobasidiomycetes, which
protrude from stomatal cavities, have a limited hymenium, and
form more or less hyaline and smooth spores. It resembles Ezo-
basidvwm in its parasitic habit, its white or yellow hymenium,, the
longitudinal division of its basidial nuclei (stichobasidial type), the
variability in number of basidiospores, to some extent in its forma-
tion of paraphyses, and in the sporidia germinating sometimes
by budding. It differs morphologically in its hypha-shaped basidia
(which cannot be recognized as such till the sterigmata and spores
appear), their inequality in height, the successive abstriction of
spores, and in the fact that the spores do not become uniseptate on
germination. It further differs in its restriction to one monocotyle-
donous family of host plants, its more virulent parasitism, and in
the fact that it is dependent on the stomatal cavities of the host for
the formation of its fruiting bodies. The author considers that Kor-
dyana represents a primitive genus of the family Exobasidiaceae.

The author makes Raciborski’s other species the type of his new
genus Brachybasidium, as B. pinangae (Rac.) Géum. on Pinanga
kuhli. This genus is held_to differ from Kordyana fundamentally
in the transverse division of its diploid nuclei (chiastobasidial type),
and further in that the basidia are borne on specialized sub-
terminal cells, which the author considers to be homologous. with
the teleutospores of the Protobasidiomycetes, in which case the
apparent hymenium must be considered as a teleutospore sorus.
He considers his new genus as the most highly evolved member of
Maire’s Tulasnellaceae-Vuilleminiaceae group.

The hymenium of Kordyana celebensis on Commelina benghal-
ensis is often invaded by a fungus belonging to the Mucedineae
which is probably parasitic on the Kordyana. Its conidia are
bicellular and provided at the free end with a single cilium.
This fungus is named Monotrichwm commelinae n. g., n. sp.

BucHHEIM (A.). Zur Biologie von Uromyces pisi (Pers.) Winter.
Vorlaufige Mitteilung. [On the biology of Uromyces pisi
(Pers.) Winter. Preliminary note.|—Centralbl. fiir Bakt., Ab.
2, lv, 21-24, pp. 507-508, 1922. |

The author has studied the specialization of Uromyces pisi on
different hosts in Moscow. Uredospores from Lathyrus pratensis
infected Pisum arvensé, P. sativum, Lathyrus nissolia, and L. arti-
culatus, but failed to infect Vicia sativa and two other species of

Vicia tested. The identity of the fungus on Lathyrus and Pisum,

_ established by Jordi in 1904, was thus confirmed.

342

Van Luyk (A.). Ueber einige Sphaeropsideae und Melanconieae
auf Nadelholzern. ee on sgme Sphaeropsideae and
Melanconieae on Coniters.|—Ann. Mycol., xxi, 1-2, pp. 183-
142, 1923. 4

The various species of Sclerophoma described on different coni-
ferous trees are discussed, and the conclusion reached that only a
single genuine species of this genus has hitherto been recorded on
conifers, namely, S. pityophila (Cda) v. H. S. pitya v. H. and
S. pityella Died. are merely forms of this fungus found ‘on the larch,
and WS. piceae, a form on the spruce. 8S. pint v. H. is not a Sclero-
phoma but Rhizosphaera kalkhofii Bub. Grove’s suggestion that
S. pitya may be identical with his Phomopsis abietina [see this
Review, i, p. 92] is regarded as requiring further testing by cultural
methods.

Notes are given on a number of species of Phoma recorded from
conifers, and also on several Melanconiaceae. Gloeosporiwm pini
Oud. is stated to be identical with Leptostroma pinastri, and the
latter fungus, together with L. laricinwm, are regarded as belonging
to the Melanconiaceae. Aposphaeria pinea Sace. is said to be
based on a misunderstanding of the fructitications, which really
belong to Ceratostomella pini Minch, while Sphaeronema pilifera
is also apparently Ceratostomella.

Ketsster (K.). Revision einiger von Fautrey aufgestellter Pilze.
(Revision of some of Fautrey’s fungi.]—Ann. Mycol., xxi, 1-2,
pp. 70-838, 1923. te

Under Ascochyta ciewmis Fautr. & Roum. [pp. 74-75] the author *

expresses his belief that there can be little doubt that«A. ettrullina
C. O. Smith [the imperfect stage of Mycosphaerella citrullina
(C. O. Sm.) Grossenb.] and A. melonis A. Potebn. are identical
with Fautrey’s fungus, which antedates the others. He suggests
also that Macrophoma decorticans All. and possibly M. cweurbita-
cearum Trav. & Migl. belong to the same species. It does not
appear, however, that authentic specimens of these fungi have been
examined by the author. .

Cercospora fabue Fautr. on Vicia faba is thought to be very near
C. rautensis Mass. on Coronilla. C. columnaris Ell. & Ev. is
regarded as an /sariopsis, and synonymous with J. griseola Sace.
C. phaseolorum Cke is, however, considered to be a true Cercospora
and, therefore, not allied to Ellis and Everhart’s fungus as the latter
thought.

VAN DER Bist (P. A.). A contribution to our knowledge of the
Polyporeae of South Africa.—South Africun Journ. of Science,
xviii, 3-4, pp. 246-293, 1922.

This is an account, with technical descriptions in’ English, of all
the species of the sub-family Polyporeae known to occur in South
Africa ; the sub-families Boleteae and Meruleae are not dealt with.
Keys to the genera and species are included, and of the latter nine

are new. The author stresses the importance of the study of this .

343

group in a country with large forest areas, as its parasitic members
reduce the annual rate of wood production, and its saprophytes
destroy wood already formed.

Tunstatu (A. C.). Notes on some fungus diseases prevalent
during season of 1922.—Quart. Journ. Sci. Dept. Indian Tea
Assoe., ili, 115-123, 1922.

Of the fungi causing root disease of tea prevalent in northern
India only one, Hymenochaete noxia | Fomes lamaoensis| produces
no spores on this host. This disease is, therefore, always the result
of contact infection, usually spreading from root to root below ground
_ but sometimes along trenches in which woody material has been

buried. It usually originates in the dead roots of jungle trees and
is especially prevalent on sandy soil. No soil treatment, however,
appears to be effective. Complete removal of all dead and infected
wood (roots, &c.) is the only reliable method of control.

Ustulina zonata not only spreads from root to root but is also
transmitted above ground by means of spores, which cause in-
fection of the plants through decaying wounds, such as dead snags or
borer holes. The disease occurs principally on acid soils, and may
be controlled to some extent by the application of heavy lime
dressings to counteract the acidity. All dead snags should be
removed and the wounds painted with 5 lb. copper sulphate in 10
galls. of rice water to which sufticient slaked lime has been added
to make a paste. MWvretzschmaria micropus resembles U. zonata in
symptoms and effects.

On some deteriorated bheels the tea has become infected with the
Jew’s ear fungus, Awricularia [A. auricula-judue], which enters
the plant through dead snags, penetrates the woody tissue and the
growing layers, and finally destroys the bush branch by branch.
The treatment recommended for the control of U. zonata is also
applicable to this disease. ;

Sphaerostilbe repens spreads similarly to U. zonata, but is more
readily controlled by heavy liming and improved drainage. The
disease is confined to water-logged, acid soils, and even badly
infected bushes recover with suitable treatment. Stiff soils,
difficult to drain, are generally infected with this fungus.

Rosellinia arcuate is distributed by spores and by spreading along
dead organic matter from bush to bush. It generally originates in
decaying snags or collections of dead leaves lying in contact with
the bushes. It also grows in dead wood buried in trenches. In
most cases liming the soil and exposure of the collars of bushes
adjacent to the infected plants will check the spread of the disease,
In order to avoid the long and tedious work of digging out all the
diseased material from infected trenches, the trenching material
should be sprinkled with lime before covering, if there there is any
reason to suspect the presence of the furigus. The continuity of
the trenches should also be broken at intervals.

Thyridaria tarda [Botryodiplodia theobromae] is probably the
most widely distributed root fungus in the tea districts of north-
eastern India but causes serious damage only in exceptional
circumstances, as, for instance, after a protracted spell of severe
drought, which diminishes the vitality of the plants. In some

344

cases sudden death from the attacks of this fungus occurs after
pruning. The fungus is most prevalent on coarse, sandy soils, and
infection is most often found when the wood is drying back from
the cut ends of branches. The latter should be protected by
painting with the mixture recommended under U. zonata, while
the application to the soil surrounding each bush of 2 to 3 oz. of
nitrate of potash has also been found very beneficial in stimulating
the development of the plants. -All heavy pruning on the soils
liable to induce the disease should be done very early, as it has
been observed that there are fewer Botryodiplodia spores about in
September and October. . Root attacks are also found, chiefly when
the roots have been injured during cultivation. Infected bushes
frequently exhibit a moribund condition and are lable to attack
by various leaf blights, especially in the case of unpruned or
lightly pruned tea. Spraying with lime-sulphur in April is recom-
mended in such cases.

Root diseases spread mainly underground and any dead wood in
the soil, is liable to act as a centre of infection. No woody tree
appears to be immune from root diseases of one kind or another
and it is useless to attempt to compile a list of trees, the stumps of
which may serve to start such diseases. The burying of infected
material in trenches is also a fruitful source of trouble, unless
accompanied by sprinkling with lime. In the case of fungi which
are able to spread above ground, decaying snags are the principal
points of infection and should be removed. The enormous losses
due to root diseases can be greatly minimized by timely precautions,
and except Botryodiplodia they can usually be controlled by
careful removal of the infected bushes immediately the attack be-
comes visible.

Black rot (Hypochnus theae) has recently caused considerable
damage in Assam. The fungus attacks the green shoots and leaves,
covering them with an exceedingly fine mycelium, the hyphae of
which are almost indistinguishable even under a microscope. The
first symptom of the disease is a slight discoloration of the leaf
which rapidly becomes darker. On drying, the patches resemble
those caused by brown blight [Glomerella cingulata], which, to-
gether with grey blight [ Pestaloz zia theae], is frequently present as
a secondary invader and helps to obscure the true nature of the
disease. Infected leaves adhere to each other wherever they are
brought into contact. In many cases the disease occurs in patches
on the bushes, unlike brown blight which is distributed all over the
plant. The basidiospores which are produced on the ends of hyphae
projecting from the mycelial net, are sprinkled over white patches
situated on healthy-looking, green portions of the under sides of the
leaves. The disease, however, is disseminated more by contact than
by spores, as the spore patches are scanty. During the period of
actual production of thé spores the spread of the disease is much
more rapid than at other times and infected bushes may be found
distributed throughout an entire section.

Owing to an incorrect diagnosis of the symptoms, the presence
of black rot in one case repor ted was not detected until ver y severe
and extensive damage had been caused. Suspected areas should be
isolated immediately and cultivated by a special gang of coolies

345

who, with their implements, &c., should be sprayed (care being
taken to avoid the face) with lime-sulphur on leaving their work.
All diseased material should be removed and burnt and the infected
plants twice sprayed with lime-sulphur solution at intervals of
a week or ten days. Three rows of bushes surrounding those
actually diseased should be included in the treatment.

JOHNSON (J.) & FRACKER (S. B.). Tobacco wildfire in Wisconsin.—
Wisconsin Univ. Agric. Coll. Bull. 348, 21 pp. 11 figs.,
1922.

The wildfire disease of tobacco (Bacteriwm tabacum) has now
spread to Wisconsin, making a total of fourteen States affected in
the six years since it was first recorded in America. During that
period it has caused losses amounting to millions of dollars. In
Wisconsin the damage in 1922 was slight, as weather conditions
were on the whole unfavourable to its spread.

As regards the source of infection, the writers confirm the views
of previous workers [see this Review, 11, p. 37] that the disease is
traceable almost exclusively to infected seed-beds. One form of
attack, apparently peculiar to Wisconsin, is that of ‘bud infection’,
resulting in a pale yellow discoloration of the bud and the surround-
ing leaves, with entire cessation of growth. This appears to be due
to the passage of toxic products from the infected areas through
the plant to the bud, causing a bleaching similar to that ordinarily
localized in the diseased spots in older leaves.

The bottom leaves of the plants are the most likely to show
infection because they are exposed for the longest time in a position
favourable to attack. They also appear to be more susceptible to
the disease. In the Wisconsin epidemic of 1922 the worst periods
of infection followed two separate storms of wind and some hail
early in the growing season. Beating rain especially promotes
a high degree of infection.

During the six months of the winter season, when there are no
tobacco plants in the fields, the number of wildfire germs is greatly
reduced by the absence of suitable material for their sustenance,
but a few evidently survive on tobacco refuse, seed-bed covers or
frames, cured leaves, and the like. Under certain conditions it
seems likely that the bacteria may overwinter on the seed, but
from the data collected on the source of seed of infected beds in
Wisconsin this is evidently not always the case.

In general the greatest injury in the field crop seems to be
caused by an upward spread of infection from the lower leaves of
the plants, so that the greater the number of primarily infected
plants set out, the greater the damage from the disease. When
however, conditions for dissemination are favourable, as during
driving rain storms, general spread in the direction of the wind
occurs, and relatively few infected plants in the field may cause an
epidemic later.

The control measures recommended are concerned chiefly with
keeping the seed-beds free from disease, and are on the same lines
as those recommended in the earlier paper referred to above. Under
Wisconsin conditions the safest plan, in case of widespread infection
before 1st July, is to destroy the crop and replant the ground from

H 2

346

healthy beds. If only a few plants are affected they may be pulled
up, buried or burnt, and replaced by healthy ones. During the
first month the tobacco is in the field, an effort should be made to
remove all infected leaves, however laborious the process. Plough-
ing under the suckers after harvesting the crop before they
make appreciable growth will effectively prevent their attack by
wildfire.

Pam (B. T.) & JocuEMs (S. C.). Wilde planten en slijmziekte,
[Wild plants and slime disease.] Vlugsch. Deli-Proefstat. te
Medan [Sumatra], 20, 3 pp., 1922.

A list is given of thirty-four wild plants, belonging to nineteen
different families, which are known to be susceptible to slime
disease (Bacterium solanacearum) in the tobacco fields of Deli,
Sumatra. More than half the names on the list are those of very
widely distributed wild plants, the most susceptible of all being
Lantana aculeata. The cultivation of the latter as a cover crop
should therefore be replaced by that of Mimosa invisa, which
is highly resistant to slime disease [see this Review, ii, p. 295].

FROMME(F.D.). Experiments in spraying and dusting tomatoes.—
Virginia Agric. Exper. Stat. Bull. 230, 15 pp., 5 figs., 1922.

Spraying experiments were undertaken in 1918 and 1919 and
a dusting experiment in 1922 for the control of tomato diseases in
Virginia. The results of the 1918 and 1919 spraying experiments
indicate that five applications of Bordeaux mixture with soap (41b.
CuSO,, 2 Ib. resin fish-oil soap, 31b. quicklime, and 50 galls. water)
provides satisfactory control of leaf blight (Septoria lycopersict) and
soft rot (probably due to Bacillus aroideae). On the basis of these
experiments it may be assumed that spraying with soap Bordeaux
will result in an average crop increase of 70 per cent. in the middle
and western sections of Virginia. Such an increase would approxi-
mately cover the cost of spraying and harvesting, when the average
price of tomatoes is 30 cents a bushel, while any increase in price
above this figure would yield a profit. Standard Bordeaux produced
less satisfactory results (86 per cent. of control compared with 68
per cent. with soap Bordeaux).

Seven applications of the Dosch copper lime dust, containing 20
per cent. monohydrated copper sulphate, at the rate of about 42 lb.
per acre per application, satisfactorily controlled tomato late blight
(Phytophthora infestans). Dusting is likely to be preferred to
spraying in the higher altitudes to which late blight is chiefly
confined, as it is much easier to carry out. The available data
indicate that it is probably not equal to soap Bordeaux in the
control of the Septoria leaf blight, and its value in regions where
late blight does not occur remains to be determined.

BEew Ley (W.). Tomato diseases.—Journ. R. Hort. Soc., xlvii,
2 & 3, pp. 169-174, 4 pl., 1922.

This paper gives short popular descriptions of the chief tomato
diseases in England, some of which are of great commercial impor-
tance. Those mentioned include damping off (various fungi, especi-
ally Phytophthora cryptogea and P. parasitica), uck-eye rot or

347

black rot (Phytophthora parasitica), stripe disease (Bacillus lathyr?),
sleepy disease (usually either Verticillium albo-atrum or, under
exceptionally high temperature conditions, Fusariwm lycopersici,
but other fungi may be concerned), ‘mildew’ (Cladosporiwm
fulvum), stem and fruit rots (Botrytis cinerea, Fusariwim, and
Penicillium spp., Bacillus carotovorus, &c.), root rots (Fusariwin
spp. and a new species of Sclerotiwm), a physiological blossom-end
rot of tomato fruit, and mosaic. Methods of control are also briefly
indicated.

Scotr (1. T.) Tomato wilt.—Missour: Agric. Exper. Stat. Bull.
197, p. 49, 1922.

In this Bulletin, which is the report of the Director for the year
ending 30th June 1922, is included a note by I. T. Scott, in which
it is stated that the growth of the causal organism of tomato wilt
(Fusariwm lycopersici) was found to be markedly influenced by the
hydrogen-ion concentration. A maximum in the growth curve was
observed at a Pu of about 4-0 to 4-5 in all cases, and a minimum at
about 5-5. This was succeeded by another less prominent maximum.
The results agree in the main with those already reported for
Gibberella saubinetii [see this Review, i, p. 340].

PAINE (S. G.). & LAcEy (MARGARETS.). Studies in bacteriosis, VII.
Comparison of the ‘stripe disease’ with the ‘Grand Rapids
disease’ of Tomato.— Ani. of Appl. Biol., ix, 3 & 4, pp. 210-
212, 1922.

A comparison between Aplanobacter michiganense E. F. Smith,
the cause of the ‘Grand Rapids’ disease of tomatoes, and an
Aplanobacter which is frequently found associated with Aacillus
lathyri in stripe disease (see Ann. Appl. Biol., vi, p. 183, 1919)
showed certain definite differences. The name Aplanobacter dis-
simulans is therefore proposed for the latter species.

Inoculations of three sets of eighteen young tomato plants with
the two species Aplanobacter and B. lathyri gave negative results
with A. dissimulans in every case. Many successful infections were
obtained with B. lathyrt and A. michiganense, the effect upon the
pith being identical. Marked differences, however, were observed
in the lesions produced by the two organisms on the exterior of the
stem. B. lathyri caused the formation of dark brown, sunken
furrows, normally without any cracking of the epidermis, while A.
michiganense produced deep fissures with margins resembling callus
formations in the outer cortex, but caused no special changes in
colouring or effects on the fruit. The two diseases therefore appear
to be entirely distinct, and the earlier suggestion that the Grand
Rapids disease might be found to be really due to Bb. lathyri is
withdrawn.

GARD (M.). Sur le dépérissement des jeunes Noyers en 1922.
[On the dying off of young Walnut trees in 1922.]—Bull. Soc.
de Path. Vég. de France, ix, 4, pp. 263-266, 1922.
This paper has already been noticed from another source [see
this Review, ii, p. 187].

348

Miugs (A. C.). Keithia on Thuya plicata.—Gard. Chron., \xxii, p.
353, 1922.

In 1918 and 1919 Keithia thujina on Thuja plicata occurred
more or less generally throughout Ireland, being specially severe in
seed-beds in Queen’s County and Wexford, and on somewhat older
plants in other parts of the country. In the autumn of 1920 the
disease appeared simultaneously in widely separated parts of the
country. A large proportion of the diseased seedlings have since
recovered and there was no serious spread of infection on older trees
after 1920. Diseased seedlings saved from the 1918-19 epidemic
were planted out, after being sprayed with copper sulphate, on low-
lying moist ground in Wexford in the spring of 1920. During
1921 and 1922 these trees have gradually regained a_ healthy
appearance, though they are not yet free from traces of the disease.

The origin of the Kecthia epidemic is somewhat obscure, since it
does not appear to be connected with any particular type of soil or
climate, and the possibility of transmission by artificial agency is
very remote. In view of the considerable economic importance of
Thuja the disease should be held in check by the regular spraying
of seed-beds and young transplants, and by sowing the seed
sparsely to prevent overcrowding, which favours the attacks of the
fungus.

Hepacock (G. G.) & Hunt (N. R.). Notes on some species of
Coleosporium, II.— Mycologia, xiv, 6, pp. 297-310, 2 pl., 1922.

ale spore ipomoeae (Schw.) Burrill is known to occur in its
aecidial stage in the area from Pennsylvania to Florida and Texas
on six species of pine, of which Pinus echinata is the most common
and susceptible host. It is now reported for the first time on
Pinus caribaea from Florida. The uredo- and teleuto-spore stages
of this fungus are found on species of Calonyction, Convolvulus,
Ipomoea, Pharbitis, and Thyella over a much wider range, from
New Jersey and Kansas in the north, to Florida and Texas in the
south. Successful inoculations were made by the authors on
species of Ipomoea, Pharbitis, and Quamoceltt.

Coleosporium ribicola (Cke. & Ell.) Arthur has been collected in
the pyenidial and aecidial stages on Pinus edulis in Colorado and
New Mexico. Its uredo- and teleuto-spore stages have been recorded
on species of Grossularia and Ribes, from Wisconsin and Montana
to Arizona and New Mexico. The fungus has been successfully
inoculated on Pinus edulis, P. pinea, and a number of species of
Grossularia and Ribes. Between 1917 and 1919 the rust suddenly
appeared in Minnesota and Wisconsin, although no aecidial host
has been found in these two states; no reason is known for this
sudden appearance and the apparent disappearance since 1919.
C. ribicola in its aecidial stage closely resembles C. tpomoeae, and
since both may occur on the same host in the north central United
States, the authors give a short comparative key to the two species.
Coleosporium solidaginis (Schw.) Thim. has been reported as
occurring naturally in its aecidial stage (Peridermiwm acicolum
Underw. & Earle) on 14 species of pine, chiefly in the eastern United
States. In the western States it has been recorded only on Pinus
contorta in Montana and Colorado. The uredo- and teleuto-spores of

349

this fungus, in its form on Solidago, have been found occurring
naturally on about 60 species of Solidago in all regions of the
United States except in some of the south-western States. It is
now reported for the first time on 29 further species, a list of which
isgiven. The form on Aster is known to occur on at least 60
species and has a range similar to that on Solidago. The results of
numerous inoculations made by the writers indicate that in the
eastern United States Coleosporium solidaginis is a rust attacking
species of Solidago but not those of Aster. The form on Aster is
apparently distinct and probably belongs to Peridermiwm mon-
tanwm Arthur & Kern which, if this is the case, is distinct from
Peridermium acicolum.

HINTIKKA (T. J.). Die ‘Wisa’-krankheit der Birken in Finnland.
[The ‘ Wisa’ disease of Birches in Finland.]—Zeitschr. fiir
Phanzenkrankh., xxxii, 5-6, pp. 193-210, 1922.

Birches (Betula alba) in certain districts of Finland, especially
among boulders on the banks of lakes, are subject to a brown
streaking of the wood, which is known commercially as ‘ lily wood’
or ‘ Finnish (Swedish) grained birch wood’ and is in considerable
demand for the manufacture of furniture. This peculiarity is locally
known as the ‘ wisa’ disease, and is stated by different authorities
to occur also in Central Europe and Russia and to be due to parasitic
attacks or to the overcrowding of the bud-knots,

The symptoms of ‘ wisa’ disease are very variable. Frequently
the affected trees present quite a normal appearance except for
a few swellings above and below the junction of the branches with
the trunk, or ruptures in the bark. The trunk may be deformed,
and is generally sloping instead of upright. The brown streaks
may occur either in the centre of the trunk or only in the outer
annual rings. The so-called ‘coarse wisa wood’ is usually found
only in the trunk, while the ‘fine-grained wisa wood’ occurs in all
parts of the tree. The latter is very popular in the trade.

A detailed description is given of the microscopic characters of
the affected wood. The first stages of the formation of the streaks
are found on 4 to 5 year old wood and consist in an enlargement of
the medullary rays, with a profuse development of stone cells in the
adjacent cortex. The cambium and wood curve inward at the
affected parts. There are no pathological alterations in the cells at
this stage and the author has failed to find any evidence of parasitic
attack. Nutritional or climatic influences are believed to be chiefly
responsible for the abnormal development.

Later on the cortex and the wood rupture internally along the
streaks and the cell contents and walls of the affected tissues turn
brown. ‘Tannin and gum appear in abundance in the cells, while
the walls of the parenchyma lose their cellulose character. In this
condition the tissues may remain for years without further altera-
tion. The fissures are overgrown by newly-formed wood, but the
surface of the wood long remains marked by depressions corre-
sponding to the internal cracks. The process of isolation of the
latter is accompanied by the formation of callus and wound wood
in a tangential direction on one side only of the wound, leading to
the formation of kinks in the wood which may resemble knots.

350

Other types of internal tissue distortions produced in various ways
during the healing process are described.

The author believes that the ‘wisa’ disease is a non-parasitic
form of gummosis, of the type described by Sorauer as latent, and
thought by him to precede the stage of visible guth flow. In
the ‘wisa’ disease the latter stage, characterized by gummy de-
generation of the cell walls and of the cell contents, is never fully
reached. While it is admitted that the symptoms suggest one of
the so-called enzymic group of diseases, this view is not supported
by the peculiar distribution of the disease, the obvious influence of
external factors and especially of climatic conditions on it, the
anatomical characters of affected tissues, and the varying sus-
ceptibility of individual trees or branches. The whole question of
the etiology of the disease is considered to be still obscure,

GuLasson (A. K.). Mortality of Sal in Buxa Division, Bengal.—
Indian Forester, xviii, 1, pp. 22-31, 1922.

An account is given of an inquiry instituted to ascertain the
causes of the high rate of mortality of sal [Shorea robusta] in the
Buxa Division of Bengal. One branch of the work consisted in
the investigation of the sal root fungus (Polyporus shoreae), ten
plots being demarcated in various parts of the Division for purposes
of observation. Two of these have now been under observation for
6 years and the others (each of 4 acres) for 45 to 53 years.

It was found to be very difficult to arrive at any accurate con-
clusion as to the rate of spread of the disease, the fungus frequently
being well established in a tree before any external signs of attack
become apparent. As regards the lapse of time between the first
perceptible sign of attack and the death of a tree, the results of the
observations were also conflicting. Some trees which had sporo-
phores on them six years ago are still alive and healthy, while
others died almost immediately after showing symptoms of in-
fection. Up to May 1921 the average mortality associated with
the sal root fungus was 1-25 per cent. per annum, the average total
mortality being estimated at 1-6 per cent. These figures are
probably above the general average over the whole forest. An
increased number of infected trees became noticeable at the end of
the observation period. As mentioned above, however, it is possible
for the disease to exist in a tree for years before producing any
external symptoms, so that it would be unsafe to make any de-
ductions from the present data as to the rate at which the infection
spreads.

A further analysis of the deaths showed that the mortality
associated with the fungus was about equal for all girth classes.
Deaths due to the fungus appear to occur in groups, thus causing
the formation of gaps in the stand. This point is of some im-
portance in growing pure plantations of sal.

The observation plots are being maintained and in time should
give further information regarding the incidence of mortality and
rate of spread of the disease.

Dr WILDEMAN (E.). Les maladies de l’Arachide. [The diseases of
Groundnut.|—Rev. de Bot. appliquée, ii, 15, pp. 631-633, 1922.
The author supports a recent recommendation by Chevalier in

351

the same Revue that uncontrolled importation of American ground-
nuts [Arachis hypogaea] into Africa should be prohibited, in view
of the danger of introducing Puccinia arachidis. He considers
that all imports of groundnuts should be controlled, since other, not
less important diseases occur elsewhere. Of these, two are
particularly mentioned, due respectively to Septogloewm arachidis
| Cercospora personata| and Bacillus solanacearum, and are stated
to cause great damage in the Dutch East Indies. The latter is
not mentioned on this crop in Africa but the former is already
known there.

GLEISBERG (W.). Das Ratsel der Hernieverbreitung. [The mystery
of the dissemination of club-root]. Nachrichtenbl. deutsch.
Pfanzenschutzdienst, li, 11, pp. 89-90, 1922.

Club-root of cabbage [Plasmodiophora brassicae] is widespread
throughout Silesia, occurring with particular frequence and viru-
lence in small holdings and allotments. In the Zoological Ex-
periment Station at Proskau a series of laboratory experiments
was instituted to ascertain the influence of the earthworm on the
spread of the disease. Three to ten earthworms of various sizes,
after being kept for a month in flower pots in infected soil, were
placed in fresh pots, the soil of which was free from infection.
Cabbage seed was sown in the latter series of pots, and also in
a corresponding number without earthworms in infected and non-
infected soil. At the end of two months the infected soil without
earthworms had 100 per cent. of the plants attacked, the healthy
soil without earthworms had 0 per cent. and the healthy soil with
earthworms had 60 per cent. The dissemination of club-root in the
soil through the agency of earthworms is thus possible. For
practical purposes it is immaterial whether the infection is carried
in the mucilage of the skin or in the intestinal contents, but the
results of further experiments indicated that Plasmodiophora
brassicae is present in an extremely virulent form in the excreta of
worms.

The results of these tests emphasize the danger of leaving de-
caying cabbage stalks in the field, as worms frequently penetrate
the tissues in large numbers in the spring. The prevalence of the
disease in small gardens and other confined areas is explained by
the shorter distances which the worms must traverse between the
cabbage plots. In the control of the disease the disinfection of
the soil is only likely to be of value if simultaneously carried out
on all plots within the range of the worms. Deep ploughing is
a purely temporary palliative, since the worms rapidly bring in-
fective material again to the surface.

THATCHER (R. W.). Forty-first Annual Report New York Agricul-
tural Experiment Station (Geneva) for 1922, 51 pp., 1923.

Some items of phytopathological interest are contained in the
report of the Division of Botany [pp. 29-34].

Raspberry disease investigations were instituted in 1922 in the
Hudson River Valley, where the future of the crop is threatened
by several diseases. A survey of the plantations showed that the
mosaic or yellows disease is universally present. For the last ten

352

years in this area the red variety Perfection has been cultivated
almost exclusively, and mosaic apparently became prevalent in the
early plantings from which all the present stands have descended.
A small quantity of healthy stock was obtained for experimental
purposes, and tests will be carried out to determine the most prac-
tical methods of selecting and growing disease-free plants. Mosaic
is the most important disease of red and purple raspberries in New
York, black raspberries, blackberries, and dewberries being also
affected by a similar and probably identical disease. Studies have
been made of the varying symptoms of mosaic, especially the first
stages, in the Division of Horticulture, and investigations are in
progress on the rate of spread of the disease from infected to
healthy plants, and the natural factors involved in its transmission.

Western blue-stem disease has ruined the black raspberry
industry in Dutchess county of recent years. The disease is not
completely understood, and no control measures are known.

Rosette or eastern blue-stem [see this Review, 1, p. 128], which
in some respects resembles mosaic, primarily attacks black and
purple raspberries. A preliminary study of its importance in New
York is in progress.

Carrots on Long Island are liable to a destructive leaf blight
caused by Muacrosporium carotae, while a root rot of unknown
origin is also of some importance. The leaf blight disease is seed
borne, and seed disinfection experiments will therefore be carried
out. Trials will also be made with Bordeaux mixture, which
appears to be a promising method of treatment.

DorpcE (ETHEL M.). [Report of the Division of] Botany and Plant
Pathology [for the year ending 30th June 1922.|—Journ.
Dept. of Agric. S. Africa, v, 6, pp. 546-549, 1922.

Citrus canker [ Pseudomonas citri| eradication continues to make
satisfactory progress, only four trees being found infected during
the year, all on one farm in the Rustenburg district. An extensive
tield experiment is being carried out to ascertain whether citrus
trees may safely be replanted after three to five years in orchards
where trees infected with canker have been removed. Citrus scaly
bark has only been known in South Africa for the last two years,
but appears to be spreading very rapidly in certain areas.

The outbreak of potato wart disease (Synchytriuim endobioticwm)

in Natal og this Review, ii, p. 10] seems to be confined to two

adjoining farms in the Impendhle Division, and it is hoped that the
disease has not become more widely distributed. No cases of in-
fection have occurred in the Boston area, near Impendhle, where
potatoes are grown in considerable quantities. ‘Two obscure diseases
of groundnut were observed ; in one case the plants turn yellow and
die without apparent cause, and in another seemingly healthy
plants produced a large crop of kernel-less nuts. Amongst the
plant diseases mentioned as being under observation in the western
Cape districts are silver leaf disease of fruit trees [Stereum pur-
purewm] and apple mildew. Other aspects of the mycological
work referred to in the Report have been, for the most part,
separately noticed in this Review.

353
In the National Herbarium at Pretoria, an up-to-date reference
index was compiled of the 1,000 odd genera of fungi represented,
with special reference to their systematic position.

Departmental Activities: Botany.—Journ. Dept. of Agric. WN.
Africa, vi, 2, pp. 114-115, 1923.

Climatic conditions in the Transvaal are stated to have been
particularly favourable for the development of anthracnose (Gloeo-
sporium ampelophagum) in grape vines in the past season, and con-
siderable damage to both shoots and fruit has resulted. Winter
treatment is recommended, which consists of pruning out and burn-
ing all affected wood and then spraying the dormant vines with a
solution of lime-sulphur (1 : 12), or swabbing them with a mixture
of iron sulphate (25 lb.), sulphuric acid (1 pint), and water (50
galls.). If after this treatment young shoots are found to be
affected, spraying with Bordeaux mixture should be carried out (a)
when shoots are eight to twelve inches in length, (>) just before the
flower-buds open, (c) just after the blossoms fall, and, if necessary,
once or twice again later.

Chlorosis in fruit trees is becoming more and more widespread in
South Africa, and while in some cases purely cultural remedies
have been effective, in others no treatment tried has had successful
results. The trouble has been reported from several districts in
Cape Colony, while in the Transvaal many apricots, plums, pears,
and apples have been affected, the latter trees in a characteristic,
variegated manner.

Report of the Minister of Agriculture, South Australia, for the
year ended 30th June, 1921, 79 pp., 1922.

The Report contains various scattered references of phytopatho-
logical interest included in the annual survey of the work of experi-
mental farms and orchards. At Berri, River Murray, Oidiwm and
anthracnose [G/oeosporiuwm ampelophagum] of the vine occurred,
the former being controlled by dusting the vines with flowers of
sulphur. A late infection by downy mildew [Plasmopara viticola]
was also reported, but no appreciable loss was caused. In the
Mount Lofty Ranges black knot of cherry, probably caused by a
fungus, occurred on old trees in several orchards. Root gall was
prevalent on the sandy soils of the Mypolonga Irrigation Area,
where it caused severe losses. Root rot (Armillaria mellea) of
apple trees was reported from several localities. Anthracnose of the
vine was prevalent, and anthracnose of the gooseberry [ Pseudopezizu
ribis| appeared in several gardens, chiefly on the Ostrich variety.

DARNELL-SMITH (G. P.). Biological Branch.— Ann. Rept. Dept. of
Agric. New South Wales 1920-21, p. 27, 1922.

The number of specimens examined on behalf of the general
public in connexion with fungous diseases of plants was the highest
on record. In conjunction with the Fruit Branch and orchard in-
spectors, field experiments have been carried out for the control of
sour sap of apple, collar rot of citrus, citrus exanthema, brown rot
of stone fruits [Sclerotinia fructigena], black spot of Williams
pears and apples [Venturia pirina and V. inaequalis], downy

H3

354

mildew of the vine [| Plasmopara viticola], the black spot disease of
orange due to Phoma [citricarpa], and Armillaria mellea on citrus.

Considerable attention was given to the bunchy top disease of
bananas [see this Review, i, p. 108, and ii, pp. 131, 372], resulting in
the isolation of a number of organisms from infected corms. Owing
to the unsatisfactory conditions under which the inoculation experi-
ments were conducted no definite conclusions as to the nature of the
disease could be drawn.

The following diseases were also under investigation: take-all of
wheat [Ophiobolus cariceti], gummosis of sugar-cane [Bacillus
vascularum], blue mould of tobacco [ Peronosporu hyoscyamt], and
the treatment of seed potatoes for scab [ Actinomyces scubies|. The
officers of the branch also submitted reports, some of which have
been prepared for publication in a scientific series, on the following
diseases: Helminthosporium of wheat |see this Review, i, p. 340],
various diseases of sorghum, aster wilt, spotted wilt of tomato,
tomato seedling diseases, Fiji disease and bunchy top of sugar-cane,
woodiness of the passion vine, brown rot of pomegranates, Alter-
naria spot of orange, Sclerotium rolfsii and its hosts, cross-inocula-
tion with Gloeosporiwm sp. from the stem of rose to apples, blotch
condition of apples, a disease of Pinus insignis [see this Review, ii,
p- 299], and palm and pepper seedling diseases.

During the year, imported plants, consisting chiefly of fruit
stocks and seeds, were examined with a view to preventing the
entrance of any serious disease into the State. Cylindrosporvwm
padi was found for the first time on some cherry stocks imported
prior to the fireblight proclamation by the Federal Government.
Powdery scab (Spongospora subterranea) was detected in Tasmanian
potatoes.

Downy mildéw of the grape, spotted wilt of tomato, brown rot
of stone fruits, and brown spot of the mandarin [Colletotrichum
gloeosporioides| were all serious. The last-named appears to be ex-
tending into new areas. A Dematiwm-like fungus resembling
Aureobasidiwm was isolated from grapes and vine leaves in Cum-
berland county.

Report on the Department of Science and Agriculture, British
Guiana, for the year 1920, 92 pp., 1922.

The Economic Biologist, Mr. G. E. Bodkin, reports that a great
reduction has taken place in the area in the Colony devoted to
Para rubber cultivation owing to the South American leaf disease
(Melanopsammopsis ule). The Departmental Station at Christian-
burg had to be abandoned as 95 per cent. of the trees were affected
by the disease, which subsequently became very prevalent at
Issorora, the yield of dry rubber from tapped trees having sunk
from 4-97 lb. in 1919 to 2-4 lb. in 1920. Trees which have been
at all seriously attacked by the disease never recover their original
vigour. The fungus is indigenous on the native rubbers, Hevea
confusa and H. guyanensis, neither of which, however, suffers to
the same extent as H. brasiliensis. The virulence of the disease
depends greatly on meteorological conditions, its ravages being
particularly severe during protracted periods of heavy rainfall. At
such times the young leaflets shrivel up a few days or even hours

355

after the buds burst. This virulent form of the disease is largely
in abeyance during relatively dry periods, the leaves remaining
green though riddled with small holes. Even slightly affected
trees show a falling off in yield and fail to make a satisfactory in-
crease in girth. In every plantation a few trees appear to be
immune from the disease, but the reason of their resistance is not
known.

Bud rot of coco-nuts was prevalent, especially among trees grow-
ing on ‘ pegassy’ soil in the north-western district. The most
severe attacks occurred on trees which had reached the bearing
stage (ten to twelve years old). Defective drainage and cultivation
were found to encourage the spread of the disease. Red ring
disease of coco-nut palms [caused by the nematode Aphelenchus
cocophilus| was also recorded.

‘Ripe rot’ of mangoes and breadfruit was observed, but was
readily controlled by the application of Bordeaux mixture.

Witches’ broom disease [| Murasmius perniciosus| of cacao was in
evidence on some estates where the proper cultural measures were
neglected.

WELSsForD (E. J.).— Yearly Report—April to December 1921.—
Rept. Agric. Dept., Zanzibar Protectorate, for 1921, p. 136, 1922.
Owing to the lack of apparatus for detailed work the greater
part of the year was spent in the examination of clove [Eugenia
caryophyllata| ‘shambas’ [gardens]. Inspection of the roots and
of soil around dead and dying trees indicated conclusively that the
sudden death of certain trees was not due to the physical constitu-
tion of the soil or to senility. ‘Two parasites were found on the
clove, which are believed to be respectively responsible for two
distinct diseases, die-back and ‘sudden death’. Experiments have
been undertaken to test the effect of a dressing of lime on the acid
soil of the shambas. So far the results have been beneficial.

Much of the ‘mhogo’ [= cassava, Munihot utilissima| crop in
Pemba is severely infected by a fungous disease which greatly
reduces the yield.

An experimental garden has been started at Weti for plant
disease work and improving existing varieties of the more useful
crops. The sweet potato, yam, mhogo, and pigeon pea are under
cultivation.

Brown (NELLIE A.). Experiments with Paris Daisy and Rose to
produce resistance to crown gall.— Phiytopath., xiii, 2, pp. 87-99,
2 pl., 4 figs., 1923.

In trying to obtain a strain of the Paris daisy [Chrysanthemum
frutescens| resistant to crown gall, the author took perfectly healthy
plants, inoculated them with bacterium tuniefaciens and when the
yalls had developed, took cuttings again, the process being repeated
several times in the hope that resistance would eventually develop.

Two series of experiments were made. In the first an apparent
resistance developed up to the fifth set of cuttings, but with a strain
of the bacterium isolated trom slowly developed galls on this set,
the resistance gave way and the plants two generations later were
killed. In the second series this virulent strain of B. tumefaciens

356

was used, and the plants died out in the sixth set of cuttings. The
results of both series are interpreted as indicating that the vitality
of the plants was considerably reduced by repeated infection with
the organism.

When the fifth set of cuttings in the first series were showing
apparent resistance to grown gall, juice from the diseased plants
was expressed and added to beef agar, and juice from healthy
plants treated likewise. Colonies of B. tumefaciens were slower in
appearing on the former medium than on the latter.

Plants inoculated with dead cultures and then in the same spot
with living ones also showed a marked decrease of successful
infections.

Breeding experiments with rose seedlings on similar lines as with
the Paris daisy, except that the plants were propagated by seed
instead of cuttings, produced a seedling which appeared quite
resistant, but in two years this resistance had appreciably lessened.

WEBER (G. F.). Septoria diseases of cereals. III. Septoria
disease of Rye, Barley, and certain grasses.—Phytopath.,
xiii, 1, pp. 1-23, 9 figs., 1923.

This paper, the last of a series of three, deals with five distinct
diseases.

The Septoria leaf blotch of rye caused by S. secalis Prill. & Del.
is described first. The disease produces small, almost circular spots
confined to the leaves or larger areas involving sometimes the whole
leaf area. The causal organism, described in 1889 from France,
grows readily in culture, producing white colonies which do not
bear conidia but only pyenidia containing 3-septate pycnospores, 2
to 3-5 by 25 to 49». Inoculations with the latter on eight kinds of
cereals showed that only rye was susceptible. The disease has
appeared more or less sparingly in the United States, but-is not of
economic importance.

Septoria leaf blotch of barley, caused by S. passerini Sace., is
characterized by lesions of a very indefinite outline, the yellow
diseased area gradually blending to the normal, and has pyenidia
which appear as black specks, not confined to the yellow areas,
containing 3-septate pycnospores measuring 1-7 to 8 by 23 to 46 p.
The organism grows well on potato dextrose agar, forming flesh-
coloured colonies of conidia (which are exactly like the pycnospores)
becoming black with age. The disease, previously reported from
Italy, is confined to barley, and it is not important economically.

Septoria leaf blotch of quack grass (Agropyron repens), caused
by S. agropyri Ell. & Ev. has only been reported from the
United States, and so far as is known A. repens is the only host
attacked. The fungus was readily obtained in pure culture and on
potato-dextrose agar developed circular, raised, smooth, conidial
colonies, first pinkish-rose in colour and later turning black. The
pycnospores and conidia are 3-septate and the former measure 1-5
to 2:5 by 24 to 45 yp.

The Septoria leat blotch of brome grass (Bromus inermis), caused
by S. bromi Sace. and previously reported from Italy, is now
recorded for the first time from the United States. It does not
guises the common cereals and is of negligible economic importance.

357

The spots resemble those caused by other species of Septoria on the
Gramineae, and the pycnidia bear spores 1-5 to 2-5 by 31 to 50 yn.
The fungus grows well in artificial culture producing a white
mycelium, which later turns olivaceous. Conidia are not mentioned.

A leaf blotch of Kentucky blue grass (Pou pratensis) is reported
as being caused by a species of Septoria which resembles S. gra-
minum, but differs from the latter in the lesions not being delimited
by veins, in the pyenidia being much less closely seriately arranged,
and in the measurements of the pycnidia, 50 to 120 in diameter,
and of the pyenospores, 1 to 1-5 by 29 to 57 yw. The fungus grew
readily in culture, the colonies consisting first of conidial masses
with scant mycelium, but later producing olivaceous hyphae, and
resembling greatly those of S. tritici, S. passerini, and S. agropyrt.
Inoculations on 40 graminaceous plants gave successful results only
on Poa pratensis.

Reppy (C. 8S.) & GoDKIN (J.). A bacterial disease of Brome-grass.
—Phytopath., xiii, 2, pp. 75-86, 2 pl., 19238.

The authors describe in this paper a new disease of brome grass
(Bromus inermis) caused by a bacterial organism.

The disease first appears on the leaves as light olive green, circular
to elliptical, water-soaked areas, with light brown centres. Later
the spots become dark brown, almost black, and a characteristic
halo, visible in the early stages, becomes more prominent. In
severely attacked plants, the panicles wither and die, producing
symptoms similar to frost injury.

Each year from 1917 to 1921 the disease occurred on Bromus
inermis in North Dakota, and it has also been noted in Wisconsin
on the same host.

Isolations were made readily and successful infections obtained
without difficulty, the ends of the first leaves turning black and
withering in two to four days, and the more typical lesions develop-
ing in three to nine days. Twenty-three species of Bromus were
found to be susceptible, although in five cases the centres of infec-
tion did not become black, but were small, sunken, and light grey,
thus resembling to a marked degree the halo blight of oats caused
by Bacteriwm coronafaciens. Inoculations with the latter organism,
however, gave negative results with all species of Bromus tried
except B. carinatus. Four cereals and six other grasses yielded
negative results with the brome grass organism, whilst Agropyron
repens and oats were slightly susceptible.

The organism reserables B. coronafaciens, but on account of the
differences in infectivity between the two organisms, the authors
regard it as a new variety, and have named it B. coronafaciens var.
atropurpurem. A long series of physiological tests was applied
to both organisms, but no striking differences could be discovered.
The brome grass organism has the group number 211.2323023 and
the same number is suggested as correct for B. coronafaciens.

NEWTON (MARGARET). Studies in Wheat stem rust (Puccinia
graminis tritici).—Zrans. R. Soc. Canada, 3rd series, Section

V, xvi, pp. 153-210, 6 pl., 3 figs., 1922.
After a brief reference to the economic importance of wheat stem

358

rust (Puccinia graminis tritici) in Canada, and to the history of

the discovery of biologic forms of the parasite, the author gives
details of her investigations, started in 1918, to determine what
strains occur in Western Canada. In her experiments she adopted
Stakman and Levine’s differential key to the biologic forms, as well
as their symbols for recording the type and degree of infection [see
this Review, 1, p. 158]. Tables and diagrams are also given, illus-
trating the results of collections and of inoculation experiments on
eleven varieties of wheat belonging to the same groups as used by
Stakman and Levine, together with a report on preliminary infection
experiments with twenty-nine species of grasses.

The investigation demonstrated the presence in Canada of four-
teen biologic forms of Puccinia graminis tritici identical with
fourteen of the forms isolated by Stakman and Levine in collections
from widely separated points in both the northern and southern
United States. This fact, the more interesting as it was previously
thought that the rust in the protected foot-hills of the Rocky Moun-
tains and in north-western Alberta, might be different from that
found in the open plains of the Red River Valley of Canada and
the United States, suggests that climate is not a controlling factor
in the distribution of these forms.

In consideration of the generally accepted hypothesis that rust
moves during the season in waves from south to north across the
continent, collections were made in the field from the time the first
pustules appeared in early summer until late in September. It was
thought that if this hypothesis were correct, and if the biologic forms
varied in point of origin, they would appear at successive dates during
the summer, varying with the remoteness of the point of origin.
Although in the three years under review no definite succession of
biologie forms was found, it was noted that the same form, XVII,
appeared first each year, having been collected as early as 5th July,
while the form IX, which attacks emmer heavily, was always one
of the last, seldom appearing before September, thus suggesting that
the former may be more local in origin, and the latter carried by
winds from farther south. Usually more than one form was found
on the same wheat variety, sometimes even on the same plant:
thus, forms III, IX, and XVII were found on a single plant in
Saskatchewan.

A striking fact emerging from these investigations is the con-
stancy of behaviour of the biologic forms. Association of the same
form with a great variety of hosts, in widely separated localities,
was without apparent effect on its biologic characters. Inoculations
on the test wheats invariably gave the same results, whether the
inoculum was obtained from the same varieties, or from very
different hosts even when the fungus had been cultured on the
latter for several generations, thus supporting the conclusions of
Stakman, Piemeisel, and Levine. The frequently expressed idea
that a permanently rust-resistant variety cannot be bred owing to
the plasticity of the rust is erroneous, and rests on the misleading
interpretation, either of the results obtained by a person unfamiliar
with the exacting technique required in the study of biologic forms,
or of the morphological variations in the uredospores; the latter
may vary in size under the influence of the resistance of the host

859

and other cultural factors, but such variations within a given form
should not be confused with true morphological distinctions.

The geographical distribution of the biologic forms is still im-
perfectly known. However, tentative maps have been prepared
showing the areas in which the six more frequently occurring forms
have been collected, but further exploration will, no doubt, extend
the limits so far found.

Referring to Stakman’s statement that ‘ Methods of breeding for
rust resistance must now be changed fundamentally. The breeder
must know and work with those forms of rust which occur in the
region for which his new variety is intended’, the author states
that the six forms I, IX, XVII, XXI, XXIX, and XXX, all of which
give the same reactions on the bread wheats, and constitute together
70 per cent. of all the collections, deserve the first attention of
Canadian wheat breeders, since there is ground to hope that when
a hard spring wheat is evolved which is resistant to any one of
these six forms, it will likewise prove resistant to the others; this
would effect a very considerable reduction in the annual losses from
wheat rust. Genetic material bearing the necessary factors for rust
resistance for eleven out of the fourteen Canadian forms hitherto
isolated, is available in the common and durum wheats. Kanred,
for instance, is immune from all of the six biologic forms pre-
dominating in the principal wheat-growing areas of Canada and
from two others, though it is susceptible to the remaining six
forms.

The second part of the paper deals with the author's researches
on the development of the parasite within the tissues of resistant
and susceptible hosts. The experiments, technical details of which
are given, showed that up to its entry through the stomata, the
development of the fungus follows the same course on either a
resistant or susceptible host. In the latter the parasite may then
continue its growth and complete its cycle with the formation of
a new uredosorus, the host apparently adjusting itself readily to
the presence of the fungus. In a resistant host, the tissues appear
to be intolerant of the parasite. The progress of the hyphae sent
out from the sub-stomatal vesicle is rapidly checked. The failure
of infection in this case appears to be due to the starvation of the
parasite by the local killing of the intolerant host tissue, as the
author has found in most cases some indication of disintegration in
the host cells before a similar breakdown could be observed in the
hyphae. Miss Allen’s suggestion [see this Review, i, p. 377] that
the resistance of Kanred wheat may be due to the narrow stomatal
openings of this variety is not supported, since some of the forms
to which this wheat is highly susceptible have germ-tubes not
appreciably narrower than those of forms from which it is immune,
and even in the latter penetration of the stomata is not rare.

A bibliography of 67 titles is appended.

Weston (W. H.) Production and dispersal of conidia in the
Philippine Sclerosporas of Maize.—Jowrn. Agric. Res., xxiii, 4,
pp. 239-277, 10 pl., 2 figs., 1923.

This paper deals chiefly with the production and dispersal of the

360

conidia of two Philippine species of Sclerospora parasitic on maize,
namely, S. philippinensis and S. spontanea. The production of
conidia on infected plants is preceded by the formation on leaves
and sheaths of characteristically discoloured, yellowish-white areas,
which are defined in the very young leaves and show no tendency
to subsequent spread. Production takes place in the greatest
relative quantity on the largest of these areas, some of the smaller
stripes and spots remaining barren, and it always occurs during the
night, generally in cool, moist weather. The conidiophores develop
during the night exclusively from the stomata, when the surface
of the plant is covered with dew or rain. From the mycelium in
the underlying tissue, branches protrude through the stomatal pores,
forming crowded groups of lobed and knob-shaped outgrowths
which are not completely developed until some two to four hours
after the surface of the plant has been covered with moisture. They
later elongate, developing successively into mature conidiophores in
about another three hours. Several conidiophores are formed at
each stoma during the night. The conidia, which mature in greatest
numbers about 2.30 a.m., are apparently set free by active ejection
from the sterigmata, rather than by passive disjunction, as pre-
viously assumed. The nocturnal development of conidiophores
follows a relatively regular cycle under normal meteorological
conditions.

Conidia are produced in enormous numbers, even a small plant
liberating sufficient to infect the neighbourhood. Estimates of the
total number of conidia produced on a single plant of Native
Yellow maize during one night ranged from 758,038,400 to nearly
6,000,000,000. This process continues night after night for months,
finally resulting in an almost inconceivable figure.

The dispersal of conidia necessarily takes place at night and
is accomplished chiefly by wind. Slight air-currents and strong
breezes are both important, since they occur very frequently at the
time of maximum conidiophore production. Violent gales do not
promote the copious production of conidia, but are important in
so far as they sweep the available conidia over greater distances.
Dispersal is also effected by splashing drops of rain or dew, laden
with conidia, either falling from infected leaves directly on to
healthy ones or being transported thence by the wind. Agents of
minor importance in the transmission of conidia are surface water,
insects, and moist infected soil.

The genus Sclerospora may be disseminated in three stages of
development—mycelium, oospores, and conidia. The first two stages
are comparatively unimportant in the Philippines, the destructive
spread of the downy mildews being almost entirely accomplished
by conidia. The spread of these diseases to the United States could
not, however, be effected by conidia unless the latter developed on
imported live plants. Oospores have not been found on maize in
the Philippines, and it is not yet known whether any of the
oospore-forming Sclerospora spp. on other Gramineae are identical
with the maize parasites. As mycelium, long-distance transport
might occur in sugar-cane (which is also attacked by S. spontanea)
or possibly in cuttings of other grasses.

361

HourpD (ANNIE M.). Hydrogen-ion concentration and varietal re-
sistance of Wheat to stem rot and other diseases.—Jowr'i.
Agric. Res., xxiii, 5, pp. 8373-384, 1923.

The present investigation was undertaken with a view to fur-
nishing additional data on the hydrogen-ion concentration of the
expressed juice of a number of wheat varieties, some resistant and
others susceptible to stem rust (Puccinia graminis). Most of the
plants used in the experiments were grown in the greenhouse, but
germinator seedlings were also studied. The hydrogen-ion con-
centrations were determined electrometrically, and most of the
measurements were made at a temperature of 25°C. Throughout
the series the procedure was to make at least three determinations
of each sample, the average of which was taken to represent the
reaction of the juice.

The most striking result revealed by the data was the absence of
any significant difference in the P,, values of the juice of resistant
and susceptible varieties of wheat. The variations in the reaction
of the juice of the plant at different stages of development were
also very slight, only a small increase in acidity being observed in
seedlings two to four weeks old over those of one week.

A table of the reactions of different well-known wheat varieties
to other common diseases besides stem rust (bunt, mildew, scab, &c.),
compiled from the observations of several investigators, indicates
very inconsistent behaviour. The only examples of uniform resis-
tance and susceptibility are Khapli and Little Club respectively.

It may be concluded from the above data that there is no correla-
tion between the hydrogen-ion concentration of the expressed juice
and varietal resistance or susceptibility to disease.

Much greater differences in the hydrogen-ion concentration of the
expressed juice were produced by environmental than by varietal
factors. Thus the P,, value of the juice of greenhouse wheat
seedlings cut at 1 p.m. averages 0-1 higher than that of those cut
at 9 am. Wheat plants grown in limed soil have a lower
hydrogen-ion concentration than those from unlimed ground.
General debility, as well as severe infection by Erysiphe graminis,
results in an abnormally high acid content. No appreciable differ-
ences in the hydrogen-ion concentration were observed in wheat
plants grown from seed originating in widely separated localities.
The concentration of hydrogen-ions in expressed wheat juice in-
creases on standing. ‘The addition of two volumes of water to one
of expressed juice increased the P,, value by 0-10 to 0-15. Young
germinator seedlings are more highly buffered against dilution than
older greenhouse plants.

BEAUVERIE (J.). Sur les rapports existant entre le développement
des rouilles du Blé et le climat. [On the relation existing
between the occurrence of Wheat rusts and climate.|—Comptes
Rendus Acad. des Sciences, elxxvi, 8, pp. 529-531, 1923.

Comparative field observations on the occurrence in 1921 and

1922 of three rusts (Puccinia graminis, P. glumarum, P. triti-

cin) on some fifty varieties of wheat, in Auvergne (France), gave

some interesting indications in view of the extremely divergent
weather conditions of the two years. In 1921, during the critical

362

period in May and the beginning of June (which the author in
previous work has given reasons for regarding as the period during
which, under local conditions, the weather exercises the maximum
influence on the wheat crop), the rainfall in the neighbourhood of
Clermont-Ferrand [for periods of ten days each] amounted to
22-9 mm., 65-6 mm., and 12-6 mm., and was followed by a period
of absolute drought up to the harvest. In 1922 the total rainfall was
considerably smaller during the earlier period, but rainy weather
followed until the end of the season. In the former year P. glu-
marum was very prevalent at the beginning of active growth and
during the wet period mentioned; as dryness set in, LP. triticina
appeared and was present with an average intensity until the
harvest, while P. graminis was totally absent. In 1922 P. glu-
marum was present to a slighter extent during the first vegetative
phase, but maintained itself on the young shoots; P. triticina
appeared a little later and developed feebly; P. graminis was the
last to appear but gained in intensity up to harvest time.

From the above observations, which, however, the author remarks
were not controlled by experiment, and which should be continued
for several years to become of practical significance, he draws the
conclusions that the wheat rusts occur in the following sequence:
(1) P. glumarum, (2) P. triticina, (8) P. graminis. The first is
a rust of the first vegetative phase and of the tillers, the second is
the chief rust in dry years, and the third is especially prevalent
during wet years. This is said to agree with the observations in
other countries. Thus, in the dry regions of the United States the
prevalent rust is P. triticina, P. graminis being seldom found; but
the latter can cause heavy damage in periods of high humidity.

Some notes are also given on the relative susceptibility of the
varieties cultivated by the author in the two years under review,
special mention being made of Kanred CI 5146, which was highly
resistant and showed no trace of rust in 1922.

BLARINGHEM (L.). Sur la résistance aux parasites cryptogamiques
d’un hybride d’Epeautre et de Seigle. {On the resistance to
cryptogamic parasites of a hybrid from Spelt and Rye. |—Buld.
Soc. de Puth. Vég. de France, 1x, 4, pp. 267-276, 2 figs., 1922.

The author describes the behaviour of a hybrid from Triticum
spelta var. T. (female) and Secale cereale (male) in regard to rusts
and ergot. A noteworthy feature of this hybrid is its great vege-
tative vigour, which results in the production of a dry weight at
least eight times that of the parents in the same growth period.
This is accompanied by feeble and delayed lignification of the
tissues, the transpiration and assimilation are prolonged after the
ears dry up, and the latter are completely sterile.

Of the parents, both the auttmn and the spring sown rye were
heavily attacked by Puccinia graminis. On harvesting in the
first days of August, fully developed sori of P. dispersa were also
found at the base of the leaf sheaths underneath the uneracked
epidermis. The spelt wheat sutfered considerably less from P.
graminis, though a late attack developed between the 25th July
and 4th August, the date of harvest. The plot sown on 4th March
was much more affected than that sown on 20th March.

‘

363

The hybrid was much more resistant to rust attacks during its
growing period than either of the parents. Teleutospores of
P. graminis showing a number of morphological divergences from
the normal appeared only on the shoots which developed after
cutting in August. The sori were larger and more confluent than
those on the wheat, and the teleutospores were much more variable
and frequently apiculate instead of rounded or flattened at the free
end. These peculiarities are thought to be the result of the softer
tissues of the hybrid and the deeper position of the sori, many of
the spores of which do not come in contact with the epidermis at
their tips.

The slow unfolding of the spikelets, which in the hybrid have
exceptionally elongated axes, seems to have been more favourable
to infection by the spores of Claviceps purpurea than was the case
with the parent rye. The ergot on the hybrid was shaped more
like a grain of wheat than of rye, a fact in harmony with the
production in other fertile wheat x rye hybrids, of grain resembling
wheat rather than rye.

O’ByRNeE (F. M.). Bordeaux-oil emulsion. Its preparation and
use.—Quarterly Bull. State Plant Board of Florida, vi, 2,
pp- 46-58, 1922.

Bordeaux-oil emulsion, the principal use of which is for the
control of citrus scab and melanose { Phomopsis citri], should be
prepared as follows :—(a) Dissolve copper sulphate in a barrel at the
rate of 1 lb. per gallon of water; ()) slake rock lime in water and
then add water until the number of gallons is equal to the number
of pounds of lime used (if hydrated lime is used double the amount
will be required). To mix 50 gallons of Bordeaux of the 3-3-50
formula, 22 gallons of water should be put into the sprayer, and
3 gallons of solution (5) added. Then put 22 gallons of water into
a barrel and add 3 gallons of solution (a). The barrelful of diluted
copper sulphate should then be poured slowly into the diluted lime
solution in the sprayer, stirring the whole time. The resulting
solution is first-class Bordeaux mixture which will stay in suspension
for a long time and adhere to the plants. While stirring rapidly,
add very slowly indeed 3 quarts of oil emulsion.

The following is the formula for oil emulsion used: 2 galls.
paraffin oil, 1 gall. water, 2 lb. caustic potash fish oil soap, 1 lb.
ground glue, and 2 to 4 oz. 50 per cent. carbolic acid or liquor
cresolis composition.

It must be remembered that infection by the scab organism occurs
some time before the disease becomes perceptible on the surface,
and the spraying should therefore be started in the early spring.
To control scab on the fruit the spray should be applied directly to
the blossom. This can be done without risk of injury. The time
to spray for melanose is from ten to twenty days after the petals
have dropped. Excellent results have been obtained for the past
three years in an experimental nursery at Gainesville by the use
of 3-3-50 Bordeaux mixture, with or without the addition of oil
emulsion, the control of scab being absolute. The operations were
carried out at fortnightly intervals from March to November, and
were not followed by any injurious results. Both ammoniacal

364

solution of copper carbonate and lime-sulphur considerably reduced
the amount of infection, but neither was equal to Bordeaux in
efficiency.

Burcer (O. F.), DE Busk (E. F.), & Briaes (W. R.). Preliminary
report on controlling melanose and preparing Bordeaux-oil.—
Florida Agric. Exper. Stat. Bull., 167, pp. 182-140, 6 figs.,
1923.

Melanose and stem-end rot, both caused by Phomopsis citri, are the
most serious diseases of citrus in Florida. The former is responsible
for a larger percentage of low-grade and unsightly fruit than any
other disease, and the latter causes more losses through premature
dropping and decay than all other agencies combined. Melanose is
distributed throughout Florida, but appears to be more prevalent
on the west coast and in the central districts than on the east
coast. Grapefruit and seedling oranges appear to be more sus-
ceptible to melanose than any other variety of citrus.

The symptoms and the life-history of the fungus are described.
The latter lives in the dead twigs and branches of citrus and the
spores produced in this situation are the source of the infection of
living tissues. The results of inoculation experiments showed that
only young and growing tissues are susceptible to the attacks of the
fungus, leaves from four to six weeks old being immune. The fruit
becomes immune about the end of May or beginning of June.

The results of a series of experiments conducted in 1921 and
1922 showed that spraying with Bordeaux mixture 3-3-50, plus
1 per cent. oil emulsion, gave very satisfactory control of the disease
and noticeably improved the appearance of the crop. As the oil
emulsion recommended contains 66 per cent. oil it requires 1% galls.
per 100 galls. Bordeaux to make 1 per cent. oil emulsion. [Ap-
parently the object of this addition is to control scale insects and
white fly. ]

Directions are given for the manufacture of Bordeaux-oil emulsion
[see preceding abstract]. All dead wood should be pruned away as
far as possible, but it is difficult to secure complete control by this
means without spraying, since it is almost impossible to remove all
the wood likely to harbour the fungus.

Winston (J. R.). Citrus scab: its cause and control.—U.S. Dept.
of Agric. Bull. 118, 35 pp., 16 pl, 6 figs., 1923.

Citrus scab, a parasitic fungous disease second in importance only
to the melanose and stem-rot disease caused by Phomopsis citri,
attacks many species of citrus in India, South China, Japan,
Hawaii, Paraguay, Brazil, Central America, Yucatan, the southern
United States, Cuba, Porto Rico, and the lesser West Indian islands.
It is also reported from the Canary Islands and South Africa. The
damage to leaves on bearing trees is slight, but a large percentage
of the early dropping of the green fruit 1s due to fruit scab. Later
attacks cause serious blemishes on the fruits and reduce their
market value.

In the nurseries the disease is severe, producing a marked
stunting effect upon seedling stocks for budding and often reducing
growth by 40 or 50 per cent. The average annual loss from scab

365

to Florida growers is about 1,000,000 boxes, and the cost of produc-
tion is greatly increased by the necessity of spraying to control the
disease. Under Florida conditions the following species are highly
susceptible: sour orange (Citrus awrantiwm), lemon (C. limonia),
calamondin (C. mztzs), and tangelo (a tangerine-grapefruit hybrid.)
The grapefruit and shaddock (C. grandis), the King, tangerine,
mandarin, and Satsuma oranges, the kid-glove group (C. nobilis),
and the citrange (a hybrid of Poncirus trifoliata and the tangerine)
are also susceptible, while sweet oranges (C. sinensis) and kumquats
(Fortunella spp.) are rarely attacked, and the Mexican or Key lime
(C. awrantifolia) and the Royal and Triumph grapefruits appear to
beimmune. The Duncan, Walters, Pernambuco, Leonardi, and Foster
varieties of grapefruit are all about equally susceptible, Hall (Silver
Cluster) being much more so, and Marsh comparatively resistant.

Scab appears on the leaves in the form of minute, circular, raised
protuberances, usually on the under surface of the leaf. After
a few days the apices of the lesions turn cream-coloured or yellow,
and with the expansion of the leaf the lesions become more con-
spicuous, some forming hollow, conical outgrowths, and others
coalescing into flattened scabs. At a later stage the lesions resemble
warts and assume a pinkish and finally olivaceous tinge. The
functions of moderately infected leaves do not seem to be seriously
impaired. On the fruit the outgrowths of the lesions are solid.
The protuberances turn from pale yellow to a dusty grey, and on
the grapefruit they eventually flatten out, so that the fruit regains
its normal shape. On the sour orange and lemon the lesions develop
into corky, raised warts. Abnormally early dropping of the fruit
or severe blemishes are frequently caused by scab, and even slight
blemishes considerably lower the commercial value of the crop.
Generally speaking, only the twigs of very susceptible varieties
are attacked, infection occurring in the form of cream-coloured
(afterwards pinkish and finally grey) warts on the succulent growth.
of vigorous nursery stock.

The cause of citrus scab was first referred to a fungus of the
genus Cladosportum by Scribner in 1887. Massee named this
fungus ‘C. citri pro tem.’ in 1899, and the latter name has come
into general use since. The earlier work, however, was erroneous,
the Sodas observed being a saprophyte unconnected with the
disease, though common on the old seeds. The true cause of the
latter was isolated by Fawcett in 1906 and erroneously named
Cladosporium citri Massee, with which, however, it has little in
common. What its systematic position really is has not yet been
determined, but it has none of the characteristics of Cladosporium.
The fungus develops well on glycerine agar, colonies being produced
on this and on other media in five to eight days at room tem-
perature. The cultures, which form very characteristic, raised,
convoluted colonies of a tawny or purplish colour and limited
growth, are figured. True conidia are borne very sparingly in
culture. In older cultures the convoluted mycelium becomes thick-
walled and develops tangled chains of constricted hyphae, which
are easily broken apart into chlamydospores. The latter are
capable of germination, and probably are the chief source of infec-
tion. The optimum temperature for the growth of the fungus was

366

found to be about 68° F., which may explain the relatively high
proportion of infection which occurs during the cool weather of
spring. The results of numerous isolation tests showed that when
once the scab fungus enters a leaf it can persist there throughout
the winter. From cultural data and field observations alike it
appears that the disease is seldom or never carried over winter on
fruit set in the spring or summer. Examination of the leaf lesions
showed that the fungus forms a compact stroma of thick-walled,
hyaline hyphae from which numerous sporophore-like stalks arise,
but no spores have been found on the latter. The host tissues are
penetrated to the depth of a few cell layers, and the affected cells
become brown and distorted. Hyperplasia often occurs beneath
the invaded area.

The spread of citrus scab is very erratic, the disease sometimes
being confined for years to asmall group of trees and then suddenly
becoming pandemic over large areas. Probably the chlamydospores
are responsible for the majority of the primary infections occurring
in the early spring, repeated examinations of the lesions having
failed to reveal the presence of conidia. In addition to old lesions
supplied with a hold-over stroma, many scars occur in which the
stromatic mass has weathered away. During the early spring there
is a marked flaking off of host and mycelial fragments which may
also contribute to the spread of the disease. ‘The relative scarcity
of scab in the drier sections of Florida and its absence in California
indicate that the fungus is largely dependent on abundant moisture
during the period when the leaves are expanding and the fruit is
setting. According to Fawcett (Journ. Agric. Res., xxi, 4, p. 243,
1921), natural infection depends also on a temperature range of
61° to 78° F., but the author’s investigations indicate that the
degree of humidity during the srowing season is the more impor-
tant determining factor. The widespread impression that grapefruit
scions on rough-lemon stocks are particularly susceptible to scab is
probably due to the fact that such trees produce a much greater
vegetative growth during the first few years than is the ease with
other root systems. There appears to be no scientific foundation
for the belief in the immunizing or sensitizing influence of the stock
on the scion. There is also no reason to suppose that the virulence
of the fungus is on the increase, or that the orange is gradually
losing its resistance. The results of an extensive series of inocula-
tion experiments (particulars of which are given) showed that the
susceptibility of the grapefruit to scab is greater immediately after
the falling of the petals, with a progressive decrease until the fruit
reaches a diameter of about three-quarters of an inch. The leaves
of all the citrus species tested were most susceptible on emerging
from the bud, reaching a stage of immunity when they have
developed to half an inch in width. All strains used in the tests
“appeared to be equally virulent. The fungus remains patho-
genic after growing on artificial media for four years. Inoculation
experiments on the fruit and leaves of the grapefruit and Satsuma
orange with Cladosporium citri from old scab scars resulted in
a very slight degree of infection.

The results of a series of spraying experiments indicated that
Bordeaux mixture, Bordeaux mixture with oil emulsion, and copper

367

soap gave absolute control of the disease. Burgundy mixture
caused a slight russeting of the foliage and lime-sulphur produced
serious defoliation. The following spray schedules are recommended
for Florida :—I. In orchards where scab is always serious. (1) Just
before growth sets in: Bordeaux mixture 3-3-50 plus 1 per cent.
oil emulsion. (2) In height of bloom: Bordeaux mixture 3-3-50
plus 0-5 per cent. oil emulsion. (3) A fortnight later: same as (2).
(4) A fortnight after (3): same as (1). Il. In orchards where scab
varies from moderate to serious. As in the foregoing schedule,
except that lime-sulphur solution 1 in 40 may be substituted for
Bordeaux mixture in the second and third applications. III. In
orchards where scab is of minor importance. Three applications of
lime-sulphur solution (1 in 30 for the first and 1 in 40 for the
subsequent applications). Nurseries can be kept commercially free
from scab by occasional applications of Bordeaux mixture plus oil
emulsion, and the treatment seems to stimulate the growth of the
seedlings. The oil emulsion recommended in this paper is the
‘Government formula’, namely: 2 galls. paraffin oil, 2 lb. fish oil
soap, and 1] gall. water, boiled together.

BALLARD (E.) & Norris (DoROTHY). Bacterial infection of Cotton
bolls.— Agric. Journ. India, xviii, 1, pp. 40-49, 1923.

A large proportion of the premature shedding of young bolls of
Cambodia cotton (Gossypium hirsutum) in South India appears, in
the light of preliminary investigations made in 1922, to be due to
a bacterial infection which is not Bacteriwm malvacearum; angular
spot was not found in the area under observation, though present
elsewhere in the Madras Presidency. No fungus was found asso-
ciated,with the early stages of the disease, which always appeared
first on the developing seeds, turning them brown and subsequently
discolouring the lint and producing a slimy rot within the boll.
The exterior of the latter was marked by black, shining spots, and
a puncture-like injury could in some cases be noticed right through
the boll wall. The organism isolated from affected bolls and con-
sidered responsible for the disease is a stout, rod-shaped bacillus,
feebly motile, Gram-positive, and non-acid fast; it grows readily
on various culture media and produces moist, whitish, translucent
colonies on cotton boll extract agar. Preliminary inoculations from
cultures gave inconclusive results.

Insect agency appears to play an important part in the dissemina-
tion of the disease, although it still remains to be proved whether
it is absolutely necessary. So far as any case has been made out,
two capsids, Ragmus morosus n.sp. and Rk. favomaculatus n.sp.,
would appear to be the most likely agents of infection. This point
of view is supported by various observations. Boll shedding
declined with the partial disappearance of these insects from the
field, in spite of the fact that this coincided with a period of strong
winds, which are known to be important factors in the distribution
of bacterial diseases. The season was very dry, and rain, another
possible method of dissemination of the bacteria, could scarcely
have played much part. Furthermore, where cotton stainers were
not found in the area under observation, only very small bolls were
shed with the symptoms described, whereas in another district

368

where cotton stainers were prevalent the diseased shed bolls were
much larger; this difference may well be due to the fact that the
capsids are unable to puncture large bolls.

The authors suggest that the disease might possibly be controlled
by the use of insecticides, and point out that it may be necessary
to find whether the insects suspected of carrying the disease have
other plant hosts.

FRIEDERICHS (K.) & Batty (W.). Over de parasitische schimmels,
die den Koffiebessenboeboek dooden. | Parasitic fungi which
destroy the Coffee berry borer.|—Meded. Koffiebessenboeboek-
fonds 6, 147 pp., 5 pl., 2 figs., 1923. (English summary.)

In this paper an account is given of two parasitic fungi capable
of destroying the coffee berry borer (Stephanoderes hampei Ferr. =
S. coffeae Haged.). The first has been known for some years in the
Dutch East Indies, but without identification. It is always found
where the beetle occurs, and is now named Botrytis stephano-
deris Bally n. sp. The diagnosis of the fungus, pure cultures of
which were readily obtained on potato agar and other media, is as
follows: mycelium white, clearly septate within the body of the
insect, internal hyphae up to 4 in diameter, and external ones up
to 2 4. Conidiophores verticillate on branches which are sometimes
thickened ; conidia 2 to 3 yp in diameter, globose, arising terminally
or laterally from small sterigmata. The lateral branches may form
secondary or tertiary branches and large heads of conidia are thus
developed (as many as 1,000 in one head). In potato cultures stout
coremia, simple or branched, and 1 to 2 em. in height, are formed.
B. stephanoderis greatly resembles B. bassiana in many respects,
but differs from the cultures of the latter from the Centraalbureau
voor Schimmeleultures examined by the authors in the much larger
number of conidia in one head, the presence of coremia, the longer
adhesion of the spores, and the yellowish tinge assumed by the
cultures in from eight to ten days. In old cultures the conidia
remain viable for at least two and a half years.

The second fungus, Spicaria javanica Bally n. sp., is much rarer
than B. stephanoderis, but is equally virulent. Jt has hitherto
been found only on dead beetles in black berries, not in the red or
green stages. The diagnosis is as follows: hyphae septate, white,
conidiophores profusely branched, length very variable, 1 to 2 ¢ in
width, numerous verticillate branches-at the apices. Conidia ellip-
tical, 2 by 1 to 1-5 4, white, afterwards purple, formed in long
chains on secondary branches produced by the primary branches.
Smooth antler-shaped coremia, yellow at the base, white at the
apex, 1 to 3 em. in height, developed in potato cultures after three
to four weeks. The colour of the fungus on dead beetles is
purplish-grey.

Insects destroyed by B. stephanoderis obstruct the bore holes
with the back part of their bodies, which are covered with the
mycelium of the fungus. Days or even weeks may elapse before
the dead insects are detected, the mycelium becoming apparent only
during rainy weather. The fungus is found chiefly on shaded
branches of the bushes. Natural epidemics of sufficient virulence
to eradicate the borer do not occur, presumably on account of the

369

rapid propagation of the insect. It is estimated, however, that the
normal number of offspring is diminished by 50 per cent. as a
result of the attacks of the fungus.

Inoculation experiments, which are described in detail, with
spores from €ultures were invariably successful both in the labora-
tory and in an experimental garden at Malang. Larvae, young and
old borers, and other insects, e. g. caterpillars of Cricula trifenestrata,
were easily infected. A considerable period often elapses before
the mycelium develops from the dead insects.

By dusting and spraying spores of B. stephanoderis on to
coffee berries, and by liberating infected beetles still able to move
freely about the plantations, the fungus was introduced into some
estates where it had not previously been found. It did not,
however, spread any further, probably on account of unfavourable
weather.

Upuor (J.C. T.). Ueber die Verwendung von Krankheitserregern
zur Bekampfung schadlicher tropischer Insekten. [The
application of pathogenic agents in the control of injurious
tropical insects.|—Tropenpflanzer, xxvi, 1, pp. 4-7, 1 fig.,
1923.

The author, writing from Florida, states that arrangements have
been made by the Florida State Plant Board for the cultivation, on
a large scale, of entomogenous fungi to check the ravages of scale
insects in the citrus plantations. The following fungi are said to
be useful against the insects named: Sphaerostilbe coccophila for
the control of Lepidosaphes beckii and L. gloveri on citrus fruits, the
San José scale (Aspidiotus perniciosus) on peaches, plums, and
pears, A. hederae on Melia azedarach, and Parlatoria pergandei on
citrus. Microcera fugikuroi controls Chrysomphalus aonidum, C.
awranti, and Lepidosaphes beckii on citrus. Ophionectria coccicolu
absolutely destroys L. gloveri, L. beckii, and Parlatoria pergande:
on citrus. Aschersonia cubensis is an extremely useful parasite of
various insects occurring on camphor, cinnamon, guava, bananas,
mango, &e., including Towmeyella liriodendri, Pulvinaria pyri-
formis, and Eucalymnatus tessellatus. Pure cultures of A. cubensis
and other entomogenous fungi will be grown on a commercial scale
by the State Plant Board and will be available for distribution at
75 cents each. A. turbinata is parasitic on the ‘ Florida wax scale’
(Ceroplastes floridensis), A. alewrodes, and Aegerita webberi on
Dialewrodes citri, and Aschersonia flavocitrina on D. citri and
D. citrifolvi.

The importance of entomogenous fungi can easily be demonstrated
by spraying citrus trees with Bordeaux mixture, which kills the
useful parasites together with other fungi. In a short time scale
and other insects, especially the white fly (Dialewrodes citri), appear
in great numbers.

The fungi flourish during the summer rains or earlier under
suitable conditions. Aegerita webberi thrives until late in the
autumn. Young or neglected orange plantations are not adapted
to the cultivation of useful fungi owing to the scarcity of foliage.

During the summer rains the trees should be sprayed with the
pure cultures with an ordinary apparatus, the spores of the fungi

370

being diluted with water and put through a coarse sieve before use.
The apparatus must be quite free from copper, to which the fungi
are very susceptible.

Bryce (G.). Experiments with the green muscardine fungus on
rhinoceros beetle larvae.—Ceylon Dept. of Agric. Bull. 65,
7 pp., 1923.

The results of inoculation experiments with two strains of the
green muscardine fungus (Metarrhiziwm anisopliae) from the
Philippine Islands and Malaya on the larvae of the rhinocerous
beetle (Oryctes rhinoceros) showed that the fungus was not markedly
pathogenic to the insect. This corresponds with Speare’s observa-
tions on the effect of I. anisopliae on the sugar-cane borer beetle
(Eaper. Stat. Hawaiian Sugar Plant. Assoc., Path. and Phys. Ser.,
Bull. 12,1912). The incubation period varied from thirty-nine to
eighty-one days. Of the two strains, the Philippine made the
better growth. The evidence from each experiment indicated that
the larvae were only attacked after a considerable period of cap-
tivity had diminished their vitality and power of resistance.
Apparently healthy larvae, under normal conditions, are not particu-
larly susceptible to the disease, and it is very questionable whether
natural infection, to which the beetles are probably subject in
Ceylon, since the fungus is known to be indigenous there, could be
appreciably increased by artificial means. The method cannot,
therefore, be reeommended for the control of the rhinoceros beetle
on coco-nuts.

BaLiinas (MADELEINE). Le Vermicularia herbarum parasite des
Gillets. [Vermicularia herbarum, parasitic on Carnations. |
—Bull. Soc. de Path. Vég. de France, ix, 4, pp. 288-289, 5 figs.,
1922.

A disease observed in the autumn of 1922 at Gagny (Seine-et-
Oise) on small-flowered carnations (? Dianthus caryophyllus) is
stated to be due to Vermicularia herbarwm (Westend.) Kicks (= V.
dianthi Westend.).

The plants were not usually killed but were partially defoliated
at the base, where the fungus occurred on both stems and leaves.
In the middle part of the plant, the leaves only bore small, black
dots, formed of sterile fungous tissue, while the top leaves were
quite clean. Mature fructifications of the typical Vermicularia
form were only found at the base of the stem or on old, severely
attacked leaves. They bore few conidia. True sclerotia were not
seen, but small, compact masses of brown cells are sometimes formed,
and possibly play a part in the overwintering of the fungus.

Brown (NELLIE A.). Bacterial leaf spot of Geranium in the
eastern United States.—Journ. Agric. Res., xxiii, 5, pp. 361-
372, 3 pl., 1923.

A bacterial leaf spot disease of the cultivated geranium (Pelar-
goniwm spp.) occurs very widely in eastern United States, mostly
on greenhouse plants, but occasionally out of doorsalso. The causal
organism, the morphological and cultural characters of which are
fully described, was isolated from diseased plants, and inoculation

371

experiments on healthy geraniums resulted in the typical symptoms
of the disease. The organism is regarded as distinct from Bacterzwm
erodit, already known to cause a disease of pelargonium leaves, and
is named Bacterium pelargonii n.sp. Suggestions for control of
the disease are given, the chief being the proper regulation of green-
house conditions and proper spacing of the plants out of doors.
Infected leaves should be removed, and very sensitive varieties dis-
carded.

DucoMET (V.). Observations sur le développement du Rhizoctone
de la Lucerne. [Notes on the development of the Rhizoctonia
disease of Lucerne.]—Bull. Soc. de Path. Vég. de France, ix,
4, pp. 812-316, 1922.

The author gives an account of his observations on the violet
root rot of Lucerne [Rhizoctonia violacea] during many years in
south-west France, especially in the Lot-et-Garonne Department.

He states that the disease is favoured by dry conditions, and also
by a shallow soil, which permits only a surface root system to
develop. The latter factor was responsible for the varying severity
of the disease in different parts of an experimental field that has
been under observation since 1919. In this field a flat portion con-
sisted of shallow soil overlying fissured calcareous rock, while the
adjoining slopes were formed of a deep clay subsoil. The disease
was practically confined to the former area, where, however, it was
absent from spots in which the soil occupied deeper ‘ pockets’ in
the rock. The real cause of the damage in the shallower soils is
considered to be insufficient water supply to the roots.

The deaths from the disease are stated to occur chiefly at the
beginning of summer and early in autumn. The former period
coincides with the onset of dry weather, but the latter is usually
wet. It is believed that actual infection of the root by the parasite
occurs chiefly during wet periods, and the deaths observed in any
one year are probably each the result of an infection contracted
during the preceding autumn. If this has made much progress
death will result during the dry season at the commencement of
the following summer, otherwise the plant survives until a further
extension occurs during wet weather later in the year.

If any advantage is to be expected from soil disinfection, as often
recommended, the treatment must be given in the autumn, but the
author is not hopeful, pending further experiments, of much success
in this direction. No evidence has as yet been obtained that it will
be possible to select resistant strains of lucerne. Attempts to inocu-
late strong and well-developed plants have failed, and the parasite,
like Armillaria mellea and Ophiobolus cariceti, is regarded as
definitely harmful only to weakly plants.

BenNetr (C. W.). Apple scab and its control.—(Quurterly Bull.
Michigan Agric. Exper. Stat., v, 3, pp. 130-134, 2 figs., 1923.
The season of 1922 was very favourable for the early development
and spread of apple scab [Venturia inaequalis], a brief popular
account of the symptoms and life-history of which is given. A
study of the rate of development and discharge of the winter spores
under Michigan conditions showed that by 17th April the great

372

majority of the ascospores which developed in the perithecia on
fallen leaves, were ripe and ready for emission during the first rain,
which occurred a week later. The spots produced by the first
infection were far enough advanced in the next three weeks to form
conidia. The danger of early infection is so great in Michigan that
the application of a pre-pink spray [see this Review, 1i, p. 71] cannot
be dispensed with.

‘Bunchy top’ and ‘choke throat’ in Bananas.—Queensland Agric.
Journ., Xvili, 5, pp. 868-369, 1922.

In order to check the spread of ‘ bunchy top’ of bananas [see this
Review, ii, p. 354], the New South Wales agricultural authorities
have prohibited the removal of suckers from certain of the Northern
River areas. They have also instituted manurial investigations
and experiments in dipping. The affected region reaches down
towards Byron Bay, and the Brunswick River area is now involved.
Plants may not be taken south of a line drawn from east to west
south of the Brunswick, and may only be imported from Queensland
with the sanction of the Government banana expert. ‘ Bunchy top’
must not be confused with ‘choke throat’, a contraction of the
‘throat’ of the banana which prevents the bunch from emerging.
This condition is brought about by a protracted spell of drought.

Banana bunchy top disease.—Queensland Agric. Jouri., xix, l,
pp. 32-383, 1923.

The results of the investigations on bunchy top of bananas con-
ducted by Darnell-Smith and Tryon in New South Wales have been
embodied in a report to the Ministry of Agriculture. The disease
has extended from New South Wales into the south-eastern corner
of Queensland, where it is causing much loss to growers. The
recent research work and field experiments have considerably nar-
rowed the problem by showing that certain theories formerly
advanced to explain the disease must be dismissed as untenable.

Field experiments have proved that the use of complete fertilizers
of varying constitution, as well as those providing mainly a single
essential plant food, do not prevent the occurrence of the disease
either in relatively rich or relatively poor soils. The loss of vigour
in banana plants by the continuous use of strains of a single origin
was also proved not to be an operative factor in bunchy top, which
occurred with equal prevalence on plants imported into the affected
area from remote districts. Negative results also followed the
application of lime or basic phosphates to the soil in order to
counteract soil acidity; while the disinfection with various fungi-
cidal preparations of suckers and the soil in which they were planted
was equally ineffective in checking the disease.

Investigations have hitherto failed to reveal the presence of fungi
capable of originating bunchy top under experimental conditions,
though certain organisms, amongst which are some belonging to
groups known to contain parasitic forms, have been observed.
Further research on these lines is in progress. A nematode has
commonly been found in the roots of plants affected with bunchy
top, but its presence is not invariable and it cannot, therefore, be
the sole cause of the disease. Jt has been suggested that the

~ sae

373

banana aphis (Pentalonia nervosa) transmits the disease from one
plant to another, or is even possibly the primary cause of bunchy
top, but general observations do not support this theory, though
field tests based on it are being carried out.

Meteorological factors do not appear to play any considerable part
in bunchy top, although a further study of climatic and soil condi-
tions in relation to the disease is necessary before a definite statement
to this effect can be made.

CunnincHaM (G. H.). Leaf-curl, bladder-plum, and cherry-curl.
Their appearance, cause, and control.—Vew Zealand Journ.
of Agric., Xxvi, 2, pp. 85-97, 7 figs., 19283.

Leaf curl, bladder plum, and cherry curl in New Zealand are
caused by Tuphrina |Exoascus] deformans, T. [E.] pruni, and T.
[ #.] minor respectively. The symptoms of these diseases and the
life-history of the fungi concerned are described and figured. Z£.
deformans attacks peaches, nectarines, almonds, and apricots in New
Zealand, being especially severe in seasons of alternating cold and
warm weather. Paragon and many other varieties of peach are
susceptible, as well as all nectarines. Under New Zealand (Hawke's
Bay) conditions Hobbs’s Royal, Charlotte, Hales’s Early, and Saunders
are resistant, but varietal susceptibility differs widely with the
locality. Seedling peaches are generally susceptible.

Bladder plum is confined in New Zealand to the plum, the so-
called Japanese plums being the most susceptible, though English
varieties are occasionally infected. The results of infection include
blistered leaves, distorted shoots, dropping of buds, and swollen and
hollow fruits.

Cherry curl appears so far to be restricted to isolated orchards in
Hawke’s Bay and Central Otago, occurring on the Black Tartarian,
Early Purple Guigne, and an unknown variety. In Germany the
fungus is stated to attack the ground cherry (Prunus chamaecerasus)
as well as P. cerasus, but the latter is the only host known in New
Zealand. There seems to be little danger of widespread infection.
The symptoms resemble those of leaf curl, but the following points
of difference should serve to distinguish the two diseases. Cherry
curl attacks only one or two leaves on a branch, and is confined to
a limited area covering about one half of the leaf. The leaf tissues
and petioles are often curved so that apex and base point in the
same direction.

Leaf curl and, to a less extent, bladder plum can be controlled
by an application of 54-50 Bordeaux mixture or 1 in 15 lime-
sulphur when the buds begin to swell. Where leaf curl infection
continues to appear throughout the season, spraying should be sup-
plemented by the excision of infected shoots. In bladder plum, and
especially in cherry curl, it is always necessary to cut out infected
shoots or branches, and this should be done in cherries shortly after
growth begins in the spring. Each wounded surface should be at
once painted with coal-tar. Bladder plum is only partly controlled
by spraying and cherry curl not at all, infection in each case coming
from a perennial mycelium in the shoots. Shoots and branches need
not be cut back to a greater distance than 2 in. below the point of
visible infection, as the mycelia do not readily grow downwards
into larger shoots.

374

WeLDOoN (G.P.). Spring spraying of Peaches with lime-sulphur.—
Monthly Bull. Dept. Agric. California, xii, 1-2, pp. 44-47,
1923. ,

Experiments in the combined control of leaf curl (Hxoascus de-
formans) and the twig borer (Anarsia lineatella) of the peach,
carried out in California in the spring of 1922 with commercial dry
and liquid lime-sulphur, gave excellent results. The experiments are
described in detail. A single spraying was given, different plots being
treated at different dates. The dry lime-sulphur was stated by the
manufacturers to be of such a strength that 2 lb. equalled 1 gall. of
the liquid preparation, and was recommended for use dissolved at the
rate of 2 lb. to 10 galls. water. The liquid lime-sulphur tested 33°
Baumé, and was used at a strength of 1 gall. to 10 galls. water.
Both gave practically complete control, and early applications in
February were as effective as the later ones in March.

The treatment should be given before the trees bloom, but even
when lime-sulphur is applied to peach trees in full flower there is
very little risk of injury. ,

VILLEDIEU (G.) & VILLEDIEU. Action des oxydes insolubles sur
le mildiou de la Pomme de terre (Phytophthora infestans).
{Action of insoluble oxides on the potato mildew (Phytophthora
infestans).|—Comptes Rendus Acad. des Sciences, clxxvi, 8,
pp. 534-536, 1923.

In a series of experiments, in which they used conidia of Phyto-
phthora infestans and various insoluble metallic oxides (of cad-
mium, nickel, cobalt, zinc, black oxide of copper, red oxide of
mercury, calcined and hydrated magnesium), the authors claim to
have established that the latter are toxic to the fungus to the extent
that they inhibit the germination of the spores. The insoluble or
slightly soluble oxides were placed in twice distilled water for at
least 24 hours, with frequent stirring, and the water filtered off in
one series, while in another the oxide was left suspended in a finely
powdered form in the water. In the former the spores germinated
normally, and gave active zoospores. In the latter the few zoo-
spores that escaped were immediately killed. Further experiments
showed that killing only took place in the immediate vicinity of
the solid particles. This toxicity is considered to be connected, in
part at least, with the basic function of the oxides used, since a
number of others tested had no such action, and besides, by reducing
the oxides to salts by the addition of mineral or organic acids, their
toxicity was very considerably diminished.

Bryce (G.). The toxicity of lime to Fomes lignosus Klotzsch.—
Ceylon Dept. of Agric. Bull. 64, 17 pp., 1923.

The application of quicklime to infected soil for the control of
Fomes lignosus, which causes considerable damage to the roots of
Hevea brasiliensis in Ceylon and elsewhere, is fairly general. .
After the removal of the diseased trees the quicklime is forked
into the soil or scattered over the surface at the rate of about 60 lb.
per tree. The effect of the lime on the fungus may be two-fold:
(1) scorching caused by direct contact; (2) toxicity produced by the
slaked lime in solution or by the alkalinity induced in the soil.

375

Quicklime having occasionally proved inettective in the field, cultural
experiments were carried out in order to obtain information as to
the growth of the fungus under acid and alkaline conditions, and
to investigate the action of quicklime on its development.

Pure cultures were obtained from a young fructification and sub-
cultured on a neutralized medium, as required, during the remainder
of the experiment. The fungus grew best on French bean agar,
forming a thick, felted mycelium interspersed with strands; on
maize and potato the growth was somewhat thinner. Particulars
are given of the titration of the media and the preparation of the
acid, alkaline, and control series of cultures. The following sub-
stances, namely, hydrochloric acid, sulphuric acid, citric acid,
caustic soda, and caustic potash, were added to the media in the
toxicity series, in different concentrations, obtained by adding
varying quantities, by volume, of normal solution to 12 cc. of
medium. Lime was added as slaked lime in weighed quantities and
as concentrated lime water solution.

The results of the experiments, which are described in detail,
showed that the fungus is capable of growth on media up to —66
Fuller’s scale, while it develops with difficulty at + 8, and is totally
inhibited at +16 of the same scale. At —8 Fuller’s scale growth
was generally equal to that on the neutral control dishes. The
fungus, therefore, is capable of growth under a wider range of
alkaline than of acid conditions. With slaked lime total inhibition
of growth occurred at a concentration of about 0-15 gm. per 11-25
gm. of medium, or 1-33 per cent. of slaked lime. Taking the top
8 in. of soil as weighing 2,000,000 lb. per acre, and the area occu-
pied by one tree as 480 sq. ft., the weight of the top 8 inches of soil
round one tree is 22,000 lb. To obtain a concentration of 1-3 per
cent. of slaked lime in this quantity of soil the amount required for
each tree would be 292 lb., or roughly five times the quantity
usually applied.

The fungicidal effect of burnt lime on Fomes lignosus mycelium
depends on the caustic action of caustic lime in direct contact with
the mycelium, and on the degree of alkalinity subsequently produced
in the soil. The proportion of caustic lime in Ceylon burnt coral
lime is only 25 per cent., as against 80 to 90 per cent. in good
European burnt lime. Hence the corresponding lower fungicidal
value of the Ceylon product. Carbonate of lime has no deterrent
effect on the growth of the fungus. Recent soil studies demonstrate
that, under Ceylon conditions, the quicklime applied to the soil is
rapidly converted into carbonate. Its effects on the mycelium of
F. lignosus, therefore, are purely ephemeral, and its application,
pending further investigations, cannot be recommended.

ParKER (T.) & Lona (A. W.). Spray spreading agents.— Bill.
Bureaw Biw-Technology (Murphy & Son, Ltd., Sheen Lane,
London), 8, pp. 252-258, 10 figs., 1923.

In this paper various experiments are described the aim of which
was to determine the value of calcium caseinate as a spray spreader.
In the first experiment, two clean sheets of glass were sprayed,
one with lime-sulphur 1 in 20 and the other with a similar solution
to which 0-2 per cent. of calcium caseinate had been added. The

376

plates were allowed to drain and photographs of them show the
deposit from the former solution in patches, whereas that from the
latter is evenly distributed.

Similar experiments with ammonium polysulphide 1 in 100,
arsenate of lead 4 1b. to 100 galls., and liver of sulphur and nicotine
petroleum emulsion gave similar results.

Dried films from lime-sulphur, ammonium polysulphide, liver of
sulphur, and lead arsenate solutions with and without the addition
of 0-2 per cent. calcium caseinate were examined microscopically,
and it was observed that the particles deposited from solutions with
the spreader were much closer together than those from solutions
without. The former therefore would probably have a greater
fungicidal efficiency.

An experiment was carried out to ascertain the effect of calcium
caseinate over the rate of settling of a suspension of lead arsenate.
The latter (4 lb. to 100 galls.) was placed in one cylinder, and a
similar suspension, with calcium caseinate added, in another, the
cylinders being shaken simultaneously for one minute before being
allowed to settle. Photographs taken at intervals show in the
former case evidence of sedimentation in five minutes, whilst after
fifteen minutes settling was nearly finished, and in an hour it was
complete; in the latter case the arsenate still showed excellent
suspension six hours later. The addition of calcium caseinate to
lead arsenate therefore obviates the necessity for very elaborate
stirring gear in the spraying machine.

A number of experiments were carried out to test the spreading
power on plants of solutions with and without the addition of
calcium caseinate. Foliage having a polished and smooth surface
(e.g. ivy, apple) yielded results similar to those on plate glass,
whilst on leaves with spines (e. g. hop, marrow) the fluid either with
or without the spreader appeared to collect in globules on the apex
of the spines, and on leaves with a waxy bloom (e.g. carnation,
savoy, cabbage) the spreader had little effect in increasmg the
spreading.

Further experimental work is stated to have shown that apple
scab [Venturia inaequalis] and American gooseberry mildew
[Sphaerotheca mors-uvae] can be controlled with lime-sulphur, 1 in
160, used in conjunction with calcium caseinate, without defoliation
or russeting.

AvDAMs (J. F.). Improving our orchard sprays with a fixative.—
Reprinted from Trans. Peninsular Hort. Soc., 1923, pp. 1-8,
1923.

In a somewhat detailed historical summary of the development
of the use of spreaders from 1885 onwards, the author, following
Moore, first points out that ‘spreading’ refers to the formation, or
maintenance after being formed, of a continuous film over the
surface of the leaf, whilst ‘adherence’ applies to the resistance of
the dried spray deposit to weathering. ‘ Wetting’ is the slight
chemical or physical affinity between the liquid and solid, and is
one of the factors producing a continuous film.

Of recent years much attention has been given to the possibility
of using casein as a spreader. This substance is colloidal in

377

character, and combines with certain other substances to form
agglutinant compounds which are very stable and extremely

resistant to moisture and atmospheric changes.

In order to obtain a preparation in liquid form and one thereby
easier to use, experiments were made to bring the casein into solu-
tion. Casein is soluble in an alkaline solution, but the process is
slow when lime is used, and the proportion of lime necessary in-
creases the volume of the resultant mixture. Sal soda was found
to be the most economical of the efficient substances tried and a
stock solution of the following composition was adopted. Casein
5 Ib., sal soda 1 lb., water 10 galls. [American]. The sal soda is
added to'the water, which is then gradually heated and the casein
added slowly during heating. The latter should become dissolved
in about 10 minutes, boiling being unnecessary. This stock solution
should be of a slimy, sticky consistency, and should be used at the
_rate of 2 qts. per 200 galls. of diluted spray solution, producing a
foam on the surface of the latter after thorough mixing. The casein
solution imparts to the spray both spreading and adhesive properties,
and the author therefore applies the term ‘ fixative’ to it.

A series of experiments was made to determine the quantity of
arsenic in the deposit of an arsenic spray with and without the
casein ‘fixative’. The increase of arsenic adhering to the leaves
when the latter was used amounted to 20 per cent. over the tontrol.

Trials with the fixative on a commercial scale with B.T\S., atomic
sulphur, lime-sulphur, and Bordeaux mixture were carried out with
very satisfactory results.

Cook (M. T.). The origin and structure of plant galls.—Scicnce,
N.S., lvii, 1462, pp. 6-14, 1923.

The author considers that the study of the pathological histology
of plants has been greatly neglected, especially in America.. Workers
_ on the various groups of galls caused respectively by insects, fungi,
nematodes, and bacteria, have generally known little of the studies
pursued by investigators in the other groups. The results of these
studies require to be correlated in order to serve as a basis for
future research in this important branch of botany.

One of the earliest problems which arose in connexion with plant
galis was the nature of the irritant, and this has not yet been fully
solved. In the case of both insect and nematode galls it is uncertain
whether the stimulus which induced their formation is mechanical
or chemical, and the same seems to be true of galls caused by fungi.
The slime mould Plusmodiophora brassicae penetrates the cells,

causing enlargement and division not only of the cells with which ,

it comes into direct contact, but also of ‘those in the vicinity. The
latter are apparently stimulated by the passage of some substance
from the diseased cells. Oedemas are well known to result from
chemical irritation, while calluses and the like are frequently due
to mechanical causes. Many insect galls are now believed to be
the result of purely mechanical stimuli.

Galls caused by bacteria may be divided into three groups:

(a) the olive knot group [Pseudomonas savastanoi], in which the

bacteria occupy small pockets and stimulate the surrounding cells;
(b) the legume nodule group, in which the bacteria are within the

378

cells; (c) the crown gall group, where the position of the bacteria
does not seem to be well understood.

There are three well defined stages in the formation of plant
galls: (1) cell enlargement or cell division or both; (2) the failure
of the affected part to differentiate into the characteristic tissues of
the normal plant organ on which the gall is formed; (3) the differ-
entiation. into the characteristic tissues of the gall. Kiister has
classified galls into two comprehensive groups: (1) kataplasmas or
those in which the structure is undifferentiated parenchyma and
(2) prosoplasmas in which there is a differentiation into other
tissues. The galls of P. brassicae on the Cruciferae are true kata-.
plasmas, intumescences are very simple kataplasmas, and bacterial
and fungous galls include kataplasmas and simple prosoplasmas.

Insect galls all originate from the meristematic cells and are at
first true kataplasmas, but many of them pass into the prosoplasma
stage in which fibrous and sclerenchymatous tissues are more or less_
prominent. The writer’s researches have consistently indicated that
insect galls always originate during early periods of very active
development in the life of the plant. In nematode galls the point
of excitation is less definite than in the insect galls, and the form
and character of the abnormality vary according to the age of the
root and the number of individuals attacking it.

Somé of the fungous galls are kataplasmas, while others are
prosoplasmas of varying degrees of complexity. In all cases the
direct modifications are mainly in the parenchyma tissues. Study
of the galls caused by the cedar and apple rust fungi have led to
very divergent conclusions. Stewart believes that galls of Gymo-
sporangium juniperi-virginiande arise from axillary buds, and that ~
each gall contains two fibro-vascular systems, one derived from the
incipient stem and the other from the leaves; the parenchyma
tissues predominate, and the fibro-vascular structures are dwarfed
and modified. He finds practically the same condition in the galls .
ot G. globosum. Reed and Crabill believe that the galls arise from
the leaf, and their descriptions indicate that in origin and structure
these galls are similar to those caused by the Cynipidae on oaks
and roses. The author has studied a number of other plant galls
due to fungi and found them to conform quite well in origin, struc-
ture, and development to insect galls in general.

The galls caused by P. brassicae have been closely studied of
recent years by Lutman, Chupp, and Kunkel. They are true kata-
plasmas, and it is evident that the cortex of the host reacts to the
organism, that the cambium is specially susceptible, and that the
. cells of the medullary rays also respond to the stimulus. The dis-
tortions of the xylem appear to be due to the force exerted by the
infected rays and other parts. The action of the organism on the
cambium tends to prevent the formation of vascular elements.

Bacterial galls must be class¢d as kataplasmas, or in some in-
stances as very low forms of prosoplasmas. The legume nodules
due to Bucteriwm radicicola and the olive knot also appear to
originate in the cambium, and are true kataplasmas. Recent
‘studies on crown gall indicate that all meristematic cells react to
b. tumefaciens, but the character of the galls depends largely on the
activity of the cells at the time of infection. The author believes

379

that the xylem seldom, if ever, reacts to stimulation by B. tuime-
Jaciens, though the sheath cells may do so. The most complex and
definite galls in this case arise from the cambium, the simpler ones

from other meristematic tissues. The development of rather weak -

fibrous tissues in the galls indicates that the crown gall is a low
type of prosoplasma. It agrees very generally in origin, develop-
. ment, and mature structure with other plant galls regardless of the
causal organism. There are, however, three marked differences
between some of the bacterial and the other galls, namely, (1) the
presence of the tumour strands in crown gall; (2) the more pro-
longed or more variable stimuli of bacterial galls; (3) the formation
of embryomas or tumours containing leaf shoots or roots attributed
to crown gall. The first appears to be a well defined feature of
crown gall, but not of other types of bacterial galls; the second and
third are still open to question. >

In answer to the author’s queries, Dr. E. F. Smith defined em-
bryomas as ‘crown galls containing aborted shoots, often in great
numbers’, and differing from the aerial tubers on potatoes caused
by Rhizoctonia solani in their adventitious character. He also
stated that the shoots resulting from inoculation with B. twme-
Jaciens do not differ from shoots arising as a result of other injuries,
except that the tumour tissues mingle with them, causing injury
and abortion. Levine, working with crown gall on Bryophyllwm
calycinum, states, however, that B. twmefuciens does not cause the
formation of the leafy shoots, but inhibits and retards normal
development ; the formation of the leafy shoots is mechanical and
secondary to that of the gall. The production of buds where they
do not normally occur has been reported by Woronin, Favorsi, and
Kunkel in Plasmodiophora brassicae infections.

The fungous, slime mould, and bacterial galls differ from the
more highly developed insect galls in the absence of any well
defined cessation of cell activity such as results in the latter case
when the larva reaches maturity.

The researches of Wells confirm the author's view that all galls
originate with the excessive development of parenchyma tissue.
Accepting Kiister’s groupings into kataplasmas and prosoplasmas,
Wells points out that the latter have arisen by evolutionary pro-
cesses. Kataplasmic evolution is the result,of progressive inhibition
of differentiation ending with tissue homogeneity. Prosoplasmic
evolution begins when homogeneity has been attained and is the
development of new tissue characters.

The author concludes that all galls originate in practically the
Same manner whatever the stimulus which excites their growth may
be. The latter must be applied to meristematic tissues, but in all
cases it appears that it may extend beyond the point occupied by
the causal organism. In most cases the stimulus is probably due
to an excretion by the organism and the reaction of cells to the
stimulus is remarkably similar whatever the nature of the latter.

Butier (E. J.). Some characteristics of the virus diseases of
_ plants.— Science Progress, xvii, 67, pp. 416-431, 1923.
In this paper the information at present available on the virus

diseases of plants is summarized and discussed. Four main groups

380

are distinguished : mosaic, infectious chlorosis, phloem necrosis, and
the peach yellows type, the last two being regarded as allied. The
work of various investigators is outlined and the symptoms of the
-diseases described. An account is given of the different methods of
transmission, the passage of the virus within the plant, and the
properties of the virus. The influence of environmental factors, in-
cluding temperature, soil, fertilizers, and light, is briefly discussed, |
and the paper concludes with some general observations on the
nature of the diseases, their economic importance, and the analogy
between them and certain diseases of animals and man.

CoLEMAN (L. C.). The transmission of Sandal spike.—Indiain
Forester, xlix, 1; pp. 6-9, 3 pl., 1923.

The author has shown in a previous paper (Dept. Agric. Mysore,
Mycol. Ser., Bull. 3, 1917) that sandal spike can be transmitted by
means of grafting, this being the only method of transmission
hitherto established. It is obvious, however, that in nature the
disease must be transmitted in some other way, either through the
roots or through the aerial portions of the tree. The fact that
sandal trees readily form haustorial connexions with the roots of
sandal as well as of other trees suggested the probability of root
transmission, and an experiment was therefore carried out to settle
the question.

During 1916 a number of seedling sandal trees were transplanted
in groups of two or three in common pits in the laboratory com-
pound and left to grow till June 1921 to ensure the development of
a good root system and the formation of haustorial connexions. On
1ith June 1921, one of the seedlings in several of these groups wag
grafted with bits of branches from a diseased tree. In the case
reported in detail the scion grew, producing the typically spiked
leaves of the stage shown by the tree from which it was taken. On
Ist July 1922, the disease was first observed breaking out simul-
taneously on all parts of the adjacent tree in the pit. This pheno-
menon differed completely from that produced by grafting, when
the disease spreads gradually from branch to branch. ‘Two months
later the roots of the two trees were examined and three haustorial
connexions were established, two belonging to the ungrafted and
one to the grafted tree. ,The haustoria were alive and apparently
functioning. Many other haustoria were unearthed, some forming
connexions between two roots of the same tree, and others being
attached to the roots of an adjacent cork tree (Millingtonia hor-
tensis). .

It is important to note that two of the above-described haustorial
connexions were of the ungrafted tree on the grafted one. The in-
fective virus or ultramicroscopic organism could readily be taken up
by these haustoria and carried into the previously healthy tree
along with the sap stream. Probably, however, any organic con-
nexion from grafted to ungrafted or vice versa would lead to
infection.

The result of this experiment, which is supported by two other
similar cases in which the roots have not yet been exposed, proyes
conclusively that spike disease is transmissible through the
haustoria, and at the same time disposes of the theory of an external

381

cause of infection. In the area in which the experiment was con-
ducted there were at least one hundred sandal trees, and not
a single case of spike has occurreel except those brought about arti-
ficially by grafting or haustorial infection as described above.

It is highly improbable that the natural transmission of spike
disease occurs only through the haustoria. New diseases of the
same general type have recently been discovered in large numbers
and in many cases insects have been definitely proved to be respon-
sible for their transmission from infected to healthy plants. Ex-
periments will be undertaken to ascertain whether insects are con-
cerned in the transmission of spike disease.

BRANDES (E. W.). Mechanics of inoculation with Sugar-cane
mosaic by insect vectors.—Jouwrn. Agric. Res., xxiii, 4,
pp. 279-283, 2 pl., 1923.

A study of the results of experiments conducted in the United
States, Java, Cuba, Hawaii, and Porto Rico, affords conclusive proof
that Aphis maidis is capable of transmitting mosaic disease of
sugar-cane. Evidence has further been’ adduced which indicates
that Peregrinus maidis and possibly Curolinaia sp. may also act as
agents of transmission.

The results of recent experiments carried out by the author
demonstrated that with A. mazdis the beak is usually placed on the
thinnest point of the cuticle covering a stomatal guard cell, and the
setae are then thrust into the cuticle by pressure. A copious secre-
‘tion is poured out at the end of the setae from the salivary glands,
and continues to exude from the tips of the setae as they pass into
the deeper tissues, forming the sheath described by Busgen in his
work on aphids and honey dew in 1891. The setae of A. maidis
pass through the sub-stomatal cavity, then either inter- or intra-
cellularly through the mesophyll cells, continuing between two cells
of the starch sheath and finally into the phloem of the vascular
bundle. During the entire process, the copious secretion from the
insect pours into the rapidly-growing tissues of the leaf, which
_remain practically ‘intact. The fact that the setae reach to the
phloem cells, rich in substances of nutritive value for micro-organ-
isms, seems specially significant. In the writer’s opinion, the
secretion above mentioned is unquestionably the medium whereby
the infective principle of mosaic is carried into the plant. A more
perfect mechanism for inoculation could scarcely be devised. There
is no apparent wound reaction on the part of the plant; atvany rate,
none could be seen in the phloem.

Sections of the leafhoppers, Peregrinus maidis and Draecula-
cephala mollipes, point to the tracheae rather than the phloem as the
object of attack with these forms. It would appear possible for the
latter insect to penetrate to: the vascular’ bundles by mechanical
pressure alone, instead of by the digesting action of saliva, which
appears to be necessary for the process in the case of A. maidis.

SaLmon (E.S.). ‘Mosaic’ disease of Hops.—Journ. Min. Agric.,
- xxix, 10, pp. 927-934, 3 fiys., 1922.
An obscure disease of hops, somewhat resembling, but distinct
from the ‘nettlehead’ or ‘eelworm’ disease is stated to belong to

382

the mosaic or ‘ virus’ group of plant diseases, and it is suspected
that the ‘nettlehead’ disease = belongs to this group and is not
caused by eelworms.

In the mosaic disease dense in the-present paper, the plant is
usually infected for some time before the symptoms become notice-
able. The stems (‘bines’) have shortened joints, are unable to
climb, and grow toa height of only four to six feet from the ground.
The leaves are somewhat curled with recurved margins (not incurved,
as in nettlehead), more or less mottled green and yellow, and,
together with the upper part of the stem, markedly brittle. All
such affected bines remain sterile. The diseased shoots may remain
green throughout the season or die off during the summer ; the roots
on examination are found to be partly dead. Less frequently—
possibly in cases of recent infection—the bine attains a normal
height and produces a varying amount of hops, but symptoms of
disease are apparent in the curling and mottling of the leaves,
especially of the lateral branches, and in certain characteristic mal-
formations of the hop-cones. In the commercial hop- gardens this
relatively mild form of the disease is probably overlooked, with the
result that the disease is spread by cuttings taken from such hills,
In rare instances the tips of the bines and lateral branches die back
for a certain distance.

The disease has been under observation for some years past both at
Wye and at the East Malling Research Station, and all the available
evidence shows that the infection is frequently spread by means of
cuttings taken from affected plants at a time when the latter were
apparently healthy. Details of several cases are given in which
the disease, in a latent form, was carried in cuttings taken from
apparently normal plants.

Attempts to control the disease by the early pulling of shoots
from affected hills, in the hope that the shoots arising later would
be healthy, gave negative results except in a very few instances.
The full control of the disease cannot be achieved until its exact
cause and the manner of infection are known, but in the mean-
time the following measures may be recommended. (1) Inme-
diate grubbing up of affected hills. (It is believed that green-flies
(aphids) and possibly other insects transmit the disease from infected
to healthy plants). (2) The careful inspection of adjoining hills for
the detection of the first signs of the disease. During June and
immediately before picking a systematic examination of the gardens
should be made. (3) Cuttings should, if possible, not be taken at
all from any garden affected with mosaic disease; if this course is
impracticable they must not, on any account, be taken from the hills
contiguous to one which has been grubbed up.

LuUNDEGARDH (H.). Die Bedeutung des Kohlensauregehalts und
der Wasserstoffionkonzentration des Bodens fir die Entstehung
der Fusariosen. [The importance of the carbonic acid content
and hydrogen-ion concentration of the soil in the origination

of Fusarium diseases. |—Bot. Notiser, 1923, 1, pp. 25-52, 4 figs.,
1923.

The results of a series of experiments carried out in 1922 showed

that a concentration of carbonic acid exceeding 1 per cent. in the

383

soil delayed the germination and development of wheat seedlings.
The addition of 3 to 5 per cent. of CO, resulted in a reduction of
germination exceeding 50 per cent. There was no trace of the
alleged stimulating effect of carbonic acid observed by previous
investigators. Corresponding tests with three species of Fusa-
rium (F. avenaceum, F. culmorwm, F. herbarum) and Gibberella
saubinetii indicated that high concentrations of CO, (3 to 7 per
_ cent.) not only exerted no retarding influence on mycelial growth,
but actually stimulated it in two cases (G. sawbinetii and F. cul-
morum). Thus it is evident that the fungi in question can thrive
in conditions which adversely affect the development of seedlings.
This fact may give a useful clue to the cause of the prevalence of
fungous attacks in impermeable soils.

The infection of growing seedlings by the fungi in question was
favoured by the presence of 2 to 8 per cent. of carbonic acid in the
air. In every case the seedlings were reduced to an enfeebled con-
dition by the carbonic acid. Under natural conditions the seedlings
are exposed to the soil atmosphere during the first few days, and if
this is rich in CO, a somewhat similar effect would be produced.
The attacks of G. saubinetit and F. avenacewm were very virulent
under such conditions, the affected plants showing the typical
symptoms of wilting, namely, a brown discoloration of the base of
the stem and a stoppage in the flow of water through the vessels.
The disease was progressive, more plants showing evident symptoms
of attack after 30 than after 9 to 12 days. The CO, treatment
ceased after 9 to 12 days, so that the later development of the
disease indicated that once infection has been promoted the
subsequent growth of the parasite within the host tissues is not
dependent’on CO, to the same degree. In certain cases, however,
the infected plants outgrew the infection and developed normally,
another typical feature of foot rot of wheat under natural con-
ditions. f

The injurious influence of impermeability of the soil may be due
not only to excess of carbonic acid but also to a deficiency of
oxygen. The latter must be very pronounced, however, to produce
any noteworthy effect, as cereals and other economic plants germinate
normally at one-fifth to one-tenth of the normal oxygen pressure.
The likelihood of such a shortage of oxygen in ordinary cultivated
soils is negligible, and the arrested development of the seedlings
used in the experiments may safely be attributed to the high
proportion of carbonic acid.

Experiments were also carried out with hydrogen-ion concentra-
tions ranging from 2-7 to 8-4, within which limits the four species
referred to above were capable of growth. The germination of
wheat was lessened at P,, 5-5 to 5-9, on each side of which the
germination curve rose to about P,, 5 and P,, 7 respectively. At
P,, 2-7 to 3-0 development of the fungi proceeded very slowly.
Morphological differences were also noticeable in the fungus cultures ;
at high concentrations several distinct colonies were formed, while
an alkaline reaction produced only a single, thin, hyphal membrane.
The results of the author’s tests with G. swubinetic confirmed those
obtained by Hopkins [see this Review, i, p. 340], the growth curve
showing a minimum at about P,, 5-6, on each side of which it rose

384

in approximately the same manner as in the wheat germination
curve. All the species showed a definite tendency to develop
a slightly alkaline reaction in the culture medium. G. sawbineti
and F. avenaceum exhibited this character most strongly, which
may account for their capacity to flourish in almost all soils and to
withstand the acidity in the sap of their host plants.

It has frequently been observed that plentiful fertilization with
organic manure, especially in a fresh condition or too late in the
season, favours the development and spread of infectious diseases.
On the results of these researches the author attributes this to the
fact that, even in moderate quantities, such.manure increases the
CO, content of the soil, with the consequences described above.

PrrestLey (J. H.) & WorrenpEN (Lerrice M.). The healing of
wounds in Potato tubers and their propagation by cut sets.—
Ann. of Appl. Biol., x, 1, pp. 96-115, 3 figs., 1923.

When the cut surface of a potato tuber is exposed to air, the
sequence of events during the healing process is as follows, the
colour changes, which are of no direct significance, being omitted.
The first step is the deposit of a fatty ‘suberin’ layer, formed by
the oxidation and condensation of the fatty substances from the
sap, along every wall of every cell at a certain depth below the cut
surface. Oxygen seems to be essential to the formation of this layer,
which develops within twenty-four to forty-eight hours and is con-
tinuous if the cut surface is exposed in a moist atmosphere, but is
broken when the air is dry, and particularly when the cut surface
is exposed to sunlight. When cut tubers are lost owing to fungous
attacks the loss can often be traced to exposure to dry air or the
sun after cutting, with consequent inefficiency of the’ protective
suberin layer.

A few days later cork is formed below the suberin deposit,
as the result of cell divisions in an active cork phellogen. This
activity appears to be promoted by the accumulation behind the
surface blocked by the suberin layer of sap-containing substances
diffusing from the vascular bundles, and by the production of an
acid reaction just below the blocked surface through the anaerobic
conversion of sugars into fatty acids. The activity of the cork
phellogen, which is roughly estimated by the number of cork layers
produced, differs with the variety of potato, and tests have shown
that Majestic,. King Edward VII, and Bishop are particularly
lacking in this respect. The results of the authors’ tests bring out
tle undesirability of cutting potato setts in sunlight or exposing
them to an exceedingly dry atmosphere before planting, and the
advantage of an interval of one or two days between cutting and
planting. The practice of treating cut setts either with slaked or
caustic lime does not appear to serve any useful purpose, at least so
far as it influences the healing of the wound.

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

APPLIED MYCOLOGY

Vou. Il SEPTEMBER 1923

Corton (A. D.). Potato pink rot: a disease new to England.—
Journ. Min. Agric., xxviii, 12, pp. 1126-1130, 1922.

During the summer of 1921 cases of potato pink rot (Phyto-
phthora erythroseptica) were discovered in Shropshire and Hertford-
shire. This is the first record of the disease in England, and
although it is not necessarily true that it is new to the country, it
is certainly as yet not present to any serious extent. As its symp-
toms in the growing plant are those of a wilt, while the denuded
stems somewhat resemble those which have been severely attacked
by Phytophthora infestans, it has possibly been mistaken for these
diseases. In Shropshire pink rot was found in six localities near
together, the variety attacked in all cases being Great Scot, grown
from Scotch seed; this fact would point to the introduction of the
disease with the seed from Scotland, where it is known to occur. In
Hertfordshire the outbreak occurred in only one isolated field which
had not been under potatoes for five years. The seed was home-
saved, and the crop during 1920 showed no signs of pink rot. The
indications are that the disease in this case was introduced with
‘London manure’ with which the field had been heavily dressed,
and which contained a large amount of vegetable débris, including
market refuse. A brief description is given of the disease, which
owes its popular name to the fact that cut surfaces of infected
tubers rapidly turn pink when exposed to the air. In some of the
western districts of Ireland it has caused considerable losses, exceed-
ing at times those due to P. infestans. It has been known there for
years, but apparently has not spread to any extent. With proper
rotation of crops, care in the use of healthy seed tubers, and pre-
cautions in regard to town manure highly contaminated with vege-
table refuse, there is no reason to fear further serious outbreaks in
England. Where pink rot has occurred, diseased haulms and
tubers should on no account be left lying about and especially not
allowed to reach the manure heap. Spraying is useless against this
disease.

[

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4
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386

DorpcE (ETHEL M.). Potato diseases.—Journ. Dept. Agric. S.
Africa, vi, 1, pp. 71-78, 1923.
In this paper an illustrated list of South African potato diseases
is given, with brief popular descriptions and recommendations as
to suitable methods of control. .

WueEtTzEL (H. H.). The Alternaria blight of Potatoes in Bermuda.
Phytopath., xiii, 2, pp. 100-103, 1 fig., 1923.

The author describes an epidemic of early blight (Alternaria
solani) of potatoes which occurred in Bermuda in the early winter
of 1921. The disease appeared about mid-November on a luxuriant
crop, and by the end of the month one-third of the potato fields
were severely affected; the best yields from blighted fields were six
barrels to one of seed planted. Features peculiarly striking in this
outbreak were (a) its suddenness, (b) its severity, (c) the size of the
leaf lesions and their similarity to those of late blight (Phytophthora
injestans), and (d) the development of large water-soaked lesions on
the stalks.

Bispy (G. R.), Hiaaam (J. F.), & Grow (H.), Potato seed treat-
ment in Manitoba.—Scient. Agric., ii, 6, pp. 219-221, 1923.

Soil infestation with the fungus that causes black seurf of
potatoes (Rhizoctonia solani) in Manitoba is such as to render the
tubers extremely liable to attack, and the results of three years’
experiments have shown that the disease cannot be controlled by
the ordinary methods of seed treatment (corrosive sublimate,
formaldehyde, and copper sulphate), found efficacious in other areas,
where infection appears to result more commonly from the fungus
on the surface of the seed.

During 1922, tests were made of the effect of planting and
harvesting tubers at different dates, on the incidence of black scurf.
Potatoes dug on 1st September showed an average of 39 per cent.
affected by the disease; those dug on 10th September, 43-3 per
cent.; on 4th October, 71-4 per cent. ; and on 13th October, 82-8 per
cent. Thus the longer the tubers were left in the ground, the
higher was the percentage of infection. The average percentage of
black scurf on potatoes planted on 5th May and dug at different
dates was 73 ; those planted on 15th May gave 80; 22nd to 26th
May, 76; 29th May to 1st June, 81; 10th June, 61-2; 20th June,
39-2; and Ist July, 42-5. Late planting within the time limits
that are practicable in Manitoba, was therefore not effective in the
prevention of the disease.

Goss (R. W.). Potato diseases in Nebraska.— Nebraska Agric.
Exper. Stat. Bull. 186, 32 pp., 12 figs., 1928.

The following potato diseases occur in Nebraska: Rhizoctonia
(Corticium vagum), Fusarium wilt and stem-end rot (F. oxyspo-
rum and F. eumarti), blackleg (Bacillus phytophthorus) [B.
atrosepticus|, scab (Actinomyces scabies), dry rot (Fusariwm
tricothecioides), early blight (Alternaria solani), mosaic and curly
dwarf, leaf roll, net necrosis, hopperburn, tipburn, black heart,
hollow heart, internal brown spot, and frost necrosis. In addition

387

to a short account of each disease there is a table showing the
symptoms, methods of transmission, and control measures.

Diseases carried on the surface of the tuber, such as scab and
Rhizoctonia, may be controlled by seed treatment with corrosive
sublimate (4 oz. to 30 galls. water). Owing to the absence of late
blight [Phytophthora infestans] in Nebraska it is doubtful whether
any advantage is to be derived from spraying.

TRINCHIERI (G.). Su la pretesa presenza, in Italia, della ‘rogna
nera’ della Patata. [On the alleged occurrence of the black
wart disease of Potato in Italy.]—Riv. di Biol., v, 1, pp. 189-
140, 1923.

Commenting on Dickson’s paper ‘ Diseases of the Potato’ [see
this Review, 11, p. 26], the author refutes the statement that wart
disease of potato [Synchytrium endobioticum] occurs in Italy,
basing himself on the results of inquiries made up to date by the
Italian Phytopathological Service. Furthermore, an order issued
by the Ministry of Agriculture in 1921, and still in force, prohibits
the importation into Italy of potatoes and of fruits and plants of all
other Solanaceae from abroad with a view to protecting the potato
crops against the introduction of the disease.

ScuuLtz (E. 8.) & Fotsom (D.). A ‘spindling-tuber disease’ of
Irish Potatoes.—Science, N.S., lvii, p. 149, 1923.

Recent investigations by the authors have shown that a potato
malady commonly known as ‘running long’ is an _ infectious
disease, transmissible from affected to healthy plants by means of
tuber and haulm grafts, leaf-mutilation inoculation, and plant lice.
The disease is perpetuated from year to year by the tubers, and in
the absence of control measures the incidence of infection in a given
stock increases annually.

Plants infected late in the season may show no symptoms of the
disease, while those infected early have erect, spindling stalks,
smaller, more upright, and darker leaves than the normal foliage,
and more cylindrical, spindling, and spindle-shaped tubers than
healthy or apparently healthy plants. The eyes of the tubers are
numerous and more conspicuous than usual. The yield is somewhat
reduced in the first year, and there is a progressive decrease in later
years in production from plants grown from spindling tubers. The
term ‘spindling-tuber disease’ is proposed as appropriate to the
symptoms described.

Further data on this and other so-called ‘ degeneration ’ diseases
of the potato will be published in a later paper.

Epson (H. A.) & SHAPOVALOV(M.). Parasitism of Sclerotium rolfsii
on Irish Potatoes.—Jowrn. Agric. Res., xxiii, 1, pp. 41-46,
3 pl., 1923.

Both the haulm and tuber of the Irish potato may be attacked
by Sclerotiwm rolfsi, the symptoms of the disease varying with the
age and environmental conditions of the plant. Very young plants
growing in extremely damp soil are most likely to show signs of
damping-off, while older plants may suffer from a rot of the roots

388

or stems, or both, with subsequent wilting of the leaves and stems,
the latter eventually lying prostrate on the ground.

Natural infection in the field was observed in an advanced stage
in several southern States, the symptoms produced generally re-
sembling those of wilt or stem blight. The stems were decayed at
or near the surface of the soil, and in some cases the rotting of the
underground tissues was so severe that only a few strands of vascu-
lar fibre remained attached if the tops were lifted. Wefts of myce-
lium or the sclerotia of the fungus would be seen clinging to the
stem or extending radially from the plant in and on the surface of
the soil.

Inoculation experiments carried out in 1919 at Arlington, Vir-
ginia, on forty tubers of the Irish Cobbler and Bliss Triumph
varieties, with two different isolations of the fungus (Sclerotiwm
nos. 126 and 127), resulted in severe infection. In 1920 the tests
were repeated on the Irish Cobbler variety only, with two sets of
plantings. In both tests the successive development of the various
symptoms of the disease was essentially the same. There were first
some missing hills where the seed pieces were destroyed in the
ground, then some of the young plants that had come up showed
symptoms of damping-off, and finally wilt, stem rot, and blight
followed in the older plants. In 1919 no tubers were found in any
of the thirty-five hills destroyed by the fungus, while the remain-
ing five hills produced very small ones. The yield of the control
plants was satisfactory. The severity of the attack of the two
isolations differed somewhat, Sclerotiwm no. 126 (from North
Carolina) destroying all the inoculated plants, while S. no. 127
(from Arkansas) appeared to be less virulent, five of the inoculated
plants, though undersized, remaining otherwise unaffected by the
disease. There was no perceptible difference in the response of the
two varieties used.

In 1920 the most serious infection with S. no. 126 took place in
the later of the two plantings or late in the earlier planting, while
with S. no. 127 the position was reversed. These results indicate
that the Arkansas isolation was more adapted to cooler, and the
North Carolina to warmer, temperatures. In this experiment the
total number of infected hills with S. no. 126 was nineteen, and with
S. no. 127 only eight, out of twenty-four inoculated in each case. The
apparently weaker pathogenicity of the latter accords well with
the results of the 1919 tests.

The markedly different parasitic action of the two Sclerotiwm
isolations and their different behaviour in the field suggest the
existence of distinct morphological strains in 8S, ro/fsii.. Taubenhaus’s
assertion that the fungus comprised neither varietal nor physio-
logical strains (Journ. Agric. Res., xviii, 3, pp. 127-138, 1919) can
be accepted only in respect of the particular strains included in his
studies, and not of the species as a whole. The sclerotia of strain
no. 126, considered relatively, were always larger than those of
no. 127, and also showed a tendency to mass in clusters.

Potato tubers naturally or artificially infected with S. rolfsiz are
subject to a rapid progressive decay, the affected tissues being prac-
tically odourless and colourless in the earlier stages, but assuming
a yellowish tinge in the older portions; they are also usually more

389

or less porous. Strain no. 126 was isolated from this type of
‘white rot’, which may, under favourable conditions of humidity
and temperature, develop into the so-called ‘ melter’ type, in which
the affected portions become very soft and watery. Both relatively
young sclerotia and young mycelium of the fungus were used with
equal success in the inoculation experiments, the inoculated tubers
being placed in glass moist chambers or stone jars at a temperature
of 20° to 22° C. for a fortnight.

The destructive effect of the fungus on tuber tissue was clearly
seen on sterile raw potato blocks inoculated in Erlenmeyer flasks.
The blocks were rapidly enveloped by a dense growth of pseudo-
parenchymatous mycelium, followed by abundant sclerotial forma-
tion in large, compact aggregates which were often an inch or more
in diameter. At the maximum of mycelial development an in-
creasing accumulation of light amber liquid appeared in the bottom
of the flasks. This liquid obviously resulted from the action of the
fungus on the potato. The mycelium did not penetrate the blocks,
and it is therefore logical to infer that digestive enzymes are
secreted which dissolve the host tissue, the latter being rendered
available to the fungus by means of diffusion and osmosis. The
middle lamellae are first softened, then the cell contents and cellu-
lose walls, the starch being evidently the last of the solids to
disappear. Partial autolysis of the mycelium and sclerotia occurred
when the cultures were left undisturbed for a sufficient period.

Disks of raw potato in water treated with enzyme preparations
of the hyphae softened to a curd-like consistency. Disintegration
took place through the softening of the middle lamellae and conse-
quent liberation of the individual cells, the process corresponding
exactly with that described above as the initial stage of decomposi-
tion by the fungus itself.

SHAPOVALOV (M.). Relation of Potato skinspot to powdery scab.—
Journ. Agric. Res., xxiii, 4, pp. 285-294, 4 pl., 1 fig., 1923.

The skin spot disease of the potato tuber has been attributed to
various organisms, and recently by Miss Owen to Oospora pustulans,
but the author regards all these alleged causes as unconvincing, and
believes skin spot to be primarily a young stage of powdery scab
(Spongospora subterranea), although various saprophytic fungi are
frequently found in the diseased spots. He states that the
geographical distribution of skin spot is markedly similar to that
of S. subterranea, and that it has not yet been reported from those
regions where the latter is unknown. O. pustulans is either rare
or entirely absent in the skin spot material of the United States,
and in spite of the continuous influx of skin spot infected tubers
into that country fails to establish itself, this behaviour being
exactly similar to that of powdery scab.

In arrangement and appearance there is a great similarity of skin
spot pustules to the closed sorus condition of powdery scab. On
some tubers all stages of S. subterranea can be seen, and it is
difficult to determine whether the infections should be classed as
skin spot or powdery scab.

The writer was not able to detect plasmodia of Spongospora in
the skin spot pustules, and suggests that this may be due to its

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390

disappearance at certain stages of development from spaces it for-
merly occupied. On the other hand, hyphae are entirely absent
from a certain number of the pustules.

The formation of new cork below a skin spot, signifying the
cessation of activity by the parasite, is inconsistent with the view
that the damage is caused by Oospora pustulans, which is said to
be invisible at lifting time, but to develop considerably in the stored
potatoes as spring approaches. On the other hand, it is quite in
harmony with the progress of powdery scab, which is active during
the growing period of the tuber, but usually is more or less checked
during storage.

Undoubted skin spot material was obtained from various parts
of the world and yielded 0. pustulans in 36-1 per cent. of cases. A
number of plantings were sterile, and various other fungi were also
obtained. SS. subterranea, only once cultured by Kunkel, naturally
did not occur. Inoculations of healthy tubers with O. pustulans,
like those of Miss Owen, gave negative results, and the view is held
that all the fungi isolated are mainly secondary invaders, developing
during the storage period, whose presence is altogether unnecessary
to give the appearance of skin spot. The principal invader in
Pennsylvania is Colletotrichum atramentarvum, in Germany a
Phoma, in England Oospora pustulans.

If skin spot is merely an immature condition of powdery scab,
then the abundance of the immature stage of the latter disease in
certain years becomes an interesting phenomenon which may be
due to various causes, e.g. an early check in the development of the
disease, a late infection, drought, or varietal response.

Cuarpon (C. E.) & VEVE (R. A.). The transmission of Sugar-cane
mosaic by Aphis maidis under field conditions in Porto Rico.
—Phytopath., xiii, 1, pp. 24-29, 1 fig., 1923.

The authors have conducted a number of experiments in Fajardo,
Porto Rico, the results of which tend to establish that the disease is
transmitted by Aphis maidis. The discovery by Wolcott, at Santa
Rita, of a quantity of A. maidis in the central whorl of leaves of
young plants, correlated with a marked increase of mosaic disease,
formed the starting-point of the investigations. In each of two large
insect-proof cages, 24 by 15 by 5 feet, forty-eight setts of the sus-
ceptible DIIII cane variety were planted at ordinary field distances.
In one case half the setts used were diseased, and the other half
healthy. A large quantity of the common grass ‘malojillo’ (Eri-
ochloa subglabra), a favourite host of A. matdis, was planted in
cage A (which was not weeded), and a number of the insects intro-
duced into it. Cage B was kept free from weeds and insects, and
served as a control. One month after planting, when the cane
plants were six to eight inches in height, the weeds in cage A, which
included, besides E. subglabra, Cyperus rotundus, Echinochloa
colona, Eleusine indica, Syntherisma sanguinalis, Portulacca
oleracea, Chamaesyce hypericifolia, Commelina sp., Amarantus
spinosus, and Ipomoea tiliacea, were systematically removed. Early
the next day (the weeding having taken place at 5 p.m.) the aphids
were seen feeding on the central whorl of the young cane plants,
where they stayed until their favourite hosts grew again, Of these

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391

Eriochloa subglabra decidedly ranked in the first order of preference,
followed by Echinochloa, Eleusine, and Syntherisma. Secondary
infection of the sugar-cane appeared quickly after this, the first case
in two weeks, and fifteen out of the twenty-four healthy plants (62-5
per cent.) were infected by the end of two months. The plants in
the control cage remained quite healthy throughout. Three of the
grasses in cage A, Syntherisma sanguinalis, Kleusine indica, and
Echinochloa colona, exhibited true symptoms of mosaic, from which,
however, the favourite aphid host, Lriochloa subglabra, appears to
be immune.

The locality in which the experiments were carried out is remote
from any possible source of infection, so that the new cases of
mosaic in cage A must have come from the diseased plants in the
cage, and it is suggested that the infection must have been trans-
mitted by A. mazdis, the only insect present.

WAKEFIELD (F. W.). A biometric study of the conidia of Macro-
sporium and Alternaria.—Pupers and Proc. Roy. Soc. Tas-
mania, 1922, pp. 27-31, 1 graph, 1923.

The dimensions of fungus spores are subject to considerable vari-
ation, and a marked lack of uniformity frequently characterizes the
descriptions of an identical fungus by different authorities. Pre-
vious investigations by the author having shown a considerable
range of variation in the dimensions of the conidia produced by
Cladosporium graminum Cda, (Scolecotrichum graminum Fckl)
and other species, a critical examination of two common species,
Macrosporium cladosporioides Desm. and Alternaria brassicae var.
citri Penz., was undertaken. These fungi have morphologically
similar spores though they are borne in a different manner on the
conidiophores. Cultures of the former were prepared on onion
leaves, and were eight days old when the measurements were made.
The Alternaria conidia were derived from a mandarin orange which
was under observation on a culture dish. All the conidia measured
in the latter series were taken from the same culture and the same
centre of infection at approximately the same time.

The total number of measurements taken was 861, viz. 540 of Ma-
crosporium and 321 of Alternariaconidia. The conidia of M. clado-
sporioides were found to vary in length from 17 to 51 yu, while the
limit of variation observed in A. brassicae var. citri was 9 to 44 u.
In the former case the number of each length closely approximated
to the curve of normal frequency, whereas in the latter the curve
was considerably more complex, and probably represented a com-
posite curve, consisting of a series of smaller, overlapping and inter-
secting curves. Each of the latter may possibly correspond to a
conidium of fixed position with reference to the conidiophore, and
in relation to the other conidia associated with it in the chain. A
study of curves of the length-variation of detached free conidia
would therefore indicate their solitary or concatenate origin, thus
facilitating the correct classification of the morphologically identical
conidia of Macrosporium and Alternaria.

Grove (W. B.). The British species of Cytospora.—Kew Bull,
Mise. Inform., 1, pp. 1-29, 1923.
The author describes the characters of the genus Cytospora in

392

detail, and mentions those features which distinguish it from
Naemospora and Libertella, two other tendril-forming genera with
which it is apt to be confounded. There are notes on the best
method of examining the fungus, the appearance of the spores as
seen from different angles, the change of colour sometimes seen in
the spore tendrils, and the type of evidence which field mycology
can produce concerning related ascigerous stages. Sixty-two -
species are admitted for Great Britain, of which half have been
referred to ascigerous forms, but the authorities for such relation-
ships are not specifically stated. In a few cases notes of phyto-
pathological interest are added. Localities in Great Britain and the
world distribution are given, together with references to the
systematic literature. The work closes with a host index of all the
British species considered valid.

Report of the College of Agriculture and the Agricultural Experi-
ment Station of the University of California, Ist July 1921
to 30th June 1922, 249 pp., 61 figs., 1922 [1923].

This report contains a brief record of the phytopathological work
in progress at Berkeley, at the University Farm, Davis, and at
Riverside. The following notes deal chiefly with some of the work
not already noticed elsewhere.

Tests of cereal varieties, hybrids, and selections resistant to
various diseases were continued by Mackie and his collaborators.
Selections from Galgalos, Emmer x Defiance, and Algernon wheats
have been obtained which have remained entirely free from bunt
[Tilletia tritici and 1’. levis] for three successive years, though the
seed grain was heavily inoculated with bunt spores each season.
Of 998 varieties of wheat tested for resistance to Puccinia grami-
nes and P. triticina under artificial epidemic conditions, forty-three
were entirely free from the former and four from the latter, while
others were very mildly attacked. P. glumaruim was found to be
able to infect a number of grasses belonging chiefly to the genera
Agropyron, Bromus, Elynvwus, and Sitanion. Strains of barley re-
sistant to scald (Rhynchosporium secalis) have maintained this
character, the best yield combined with high resistance being given
by Mariout C. 2775. Tests of the effect of sowing at different dates
on this disease indicate that the attack on Coast or common barley
is negligible for sowings after 20th January, and on common
Mariout after lst March.

Further work by Fawcett and Camp confirmed the identity of
Bacterium citrarefaciens Lee, the cause of citrus blast, with the
previously described Bact. citriputeale Smith, which causes black
pit. The difference in the symptoms described in the two cases” is
due to differences in climatic conditions in the north of the State,
where blast was found, and in the south, where black pit is preva-
lent. In the latter region symptoms resembling blast have now
been found at high elevations and in moist, cloudy weather. Injury
to the wing of the petiole is responsible for much of the infection.
The organism can also attack Quercus wislezenit. Bartholomew
has found that the black discoloration and ultimate breakdown
of lemons, especially those suffering from internal decline [see
below, p. 406], in storage or transit, is not caused by the spread

393

of internal decline through the tissues, but is due to infection
by a species of Alternaria. Considerable losses have occurred in
certain sections from this trouble, and control measures are under
investigation. Shell bark of lemon trees has been investigated by
Fawcett, whose cultural and inoculation experiments indicate that
a fungus may be involved in the development of this disease.

Investigations of a disease occurring on the black walnut (Juglans
californica) in two walnut-growing sections, have been conducted
by Barrett and Batchelor. Both crown and roots may be attacked,
and it is believed that a specific organism is concerned in the injury.
Excessive moisture is probably a predisposing factor in the occur-
rence of the disease.

The results of further experiments by Fawcett on the prevention
of brown rot due to Pythiacystis citrophthora showed that this
decay was prevented on heavily infected fruit by washing with
water at 115° F. for one minute or longer, and at 120° or 125° F.
for half a minute or more. The development of brown rot on
heavily infected fruit stored at 60° F. was prevented by treating
with water at 115° F. for two minutes at any time within eight
hours from the time of infection, and at 120° for two minutes at
any time within thirty hours. The standard copper sulphate treat-
ment of 1 in 1,000 was of little value after the lapse of four hours,
and of none after eight hours.

The results of preliminary tests by E. H. Smith indicate that
gradual infection by strains of Pythiacystis may take place at the
crown of the roots of stone fruit trees seven or eight years old,
provided the fungus comes into contact with a cut or bruise on the
bark, even under normal soil and moisture conditions. The most
vigorous tree inoculated showed the most infection, viz. an advance
of 4 to ¢ inch from the inoculation between January and May.

The same worker reported a disease similar to the eastern rough
bark of apples, caused by Phomopsis mali, on slow-growing, mature
pear trees near the coast. The Phomopsis isolated from the
cankers strongly resembles the eastern organism, and appears to be
identical with that previously reported as causing a die-back of
young pomaceous trees in the same districts.

_ During the spring of 1922, bacterial gummosis of stone fruits,
caused by Bacterium cerasi Griffin, occurred with unprecedented
severity, climatic conditions having been exceptionally favourable
for infection. According to Barrett, Bordeaux mixture gave
promising results in the control of the disease in the Hemet
district. The results of searification experiments carried out by Tufts
and Day, in March and April, with a view to arresting the cankers
formed by this organism, were very satisfactory, the development
of all the cankers being checked. This procedure consists of cutting
off a thin slice of the outer bark and applying a disinfectant to
destroy the bacteria in the affected area thus exposed. Several
disinfectants were tried and the concentrations determined which
would not destroy the cambium below the scarified bark. One
part formalin solution (37-3 per cent.) to five parts 50 per cent.
wood alcohol controlled the disease on apricots and almonds, but
this concentration killed the cambium of cherry and plum trees,
One part of formalin to ten of water would probably be safe for
I2

394

the latter species. | The work has not progressed far enough to
prove that the bacteria were totally destroyed, but it is highly
probably that the scarified cankers are cured. Similar tests with
the fireblight (Bacillus amylovorus) canker on pears gave pro-
mising results. Observations extending from 1919 to 1922 on some
forty varieties of apricots have shown that the Russian varieties,
Black and Catherine, are entirely free from attack by B. cerasi,
while the following are resistant: Large Early Montgamet, Early
May, Rualt, Apricot Hybrid, Nicholas, and Alexander.

C. O. Smith continued his studies on the resistance to crown gall
| Bacterium tuwimefaciens| of various species of Prunus. A high
degree of resistance has been exhibited by the Japanese apricot,
P. mume, which withstood a number of artificial inoculation tests.
Six species of pear stocks (Pyrus calleryana, P. betulaefolia, P. ‘ba
Li’, P. serrulata, P. serotina, and P. wsswriensis) planted in close
proximity to stumps of trees killed by Armillaria mellea were
found to be in a healthy condition after two years.

FREEMAN (W. G.). Administration Report of the Director of
Agriculture for the year 1921.—Dept. of Agric. Trinidad
and Tobago, 12 pp., 1922. ;

The following references to the diseases of economic crops are
of interest. A special campaign was waged against the mosaic
disease of sugar-cane, over 2,000 acres in the northern district
of Trinidad being regularly inspected. The average infection at the
beginning of the inspection course was 106 stools per acre, while at
the close of the season it had been reduced to less than two. These
encouraging results justify the hope that, with the continued co-
operation of the planters, the disease may shortly be entirely
eradicated.

Anthracnose (withertip or blossom blight) of limes [Colleto-
trichum gloeosporioiles|, first reported in 1918, is extremely
widespread in Trinidad, occurring even on an isolated old tree at
an elevation of over 800 ft. on the island of Chacachacare. In
Tobago it appears to be present only on one estate where the limes
were destroyed. By Regulations of 27th October [1921] the
removal of lime plants, or parts thereof, from the infected area was
prohibited. The Rangpur lime, stated to be resistant to anthrac-
nose, has been introduced into Tobago.

Bud rot of coco-nuts was also prevalent.

Beyan (W.). Annual Report of the Director of Agriculture,
Cyprus, for the year 1921, 11 pp., 1922.

The only references of phytopathological interest in this Report
are to the damage caused by Peronospora [Plasmopara] viticola
in the Paphos and Limassol vineyards and the losses from Ozdiuni
tuckeri [Uncinula necator] consequent upon neglect of spraying.
Active measures for the control of P. viticola were undertaken by
the Department of Agriculture under an Order in Council, but
weather conditions interfered with the operations at a critical
period and it was also difficult to ensure the co-operation of
the vine growers. The matter is receiving attention and further
measures will be taken to control the disease.

395

EastHam (J. W.). Report of Provincial Plant Pathologist,
Vancouver.—Sixteenth Ann. Rept. Dept. of Agric. British
Columbia for the year 1921, pp. 64-69, 1922.

Amongst the new diseases noted during 1921, the wilt or Sclero-
tinia disease of clover (S. trifoliorwm) caused severe injury to red
clover in the Kootenay District. There is no evidence as to how
the fungus was introduced, but its presence in British Columbia is
decidedly serious, as it can attack a number.of leguminous forage
plants, including lucerne. Sweet clover [Melilotus|, which is re-
sistant to, if not immune from wilt, should be substituted for the
susceptible varieties whenever possible.

Buck-eye rot of tomatoes (Phytophthora terrestris) caused some
damage to the lower fruits in a Victoria greenhouse. In picking
it is almost impossible to detect the early stages of infection, with
the result that affected tomatoes decay in transit.

White pine blister rust (Cronartiwim ribicola) [see this Review, i,
p- 253], first detected at North Vancouver on 10th September 1921,
was subsequently found to be widely distributed in the coastal
section of the province. A quarantine was immediately put into
effect to prevent the movement of Aibes and five-leaved pines
from the infected area into the eastern part of the province, which
is presumably free from the disease. Most of the Dry Belt is
included in the protected area.

Late blight of potatoes [Phytophthora infestans| was severe in
eastern areas. The disease provisionally termed ‘skin spot’ in
a previous report has now been identified as a form of powdery
scab [Spongospora subterranea ; see also this Review, ii, p. 389].

Fireblight | Bacillus amylovorus] was present in a severe form in
parts of the Okanagan Valley, and heavy infection was also found
near Cranbrook. The recent embargo placed by the Common-
wealth of Australia on all trees or fruits of host plants of B.
amylovorus from countries in which fireblight is known to occur is
considered to be unnecessarily sweeping. Considerable fruit areas
in British Columbia have never been invaded by fireblight, and it
is believed that shipments of fruit from such districts might
reasonably be admitted into Australia under guarantee.

ProwsE (V. McN.). Report of the Acting Economic Botanist and
Plant Pathologist.—Ann. Rept. Dept. of Agric. Western
Australia for the year ended 30th Jwne 1922, p. 31, 1922.

The most important feature of phytopathological interest during
the year was the appearance of a new citrus disease at Kalamunda,
Western Australia. The trouble was at first believed to be due to
the fungus Phoma omnivora, the cause of withertip, but the
subsequent examination of a further consignment of material
showed that another fungus accompanied the withertip organism,
and produced somewhat different symptoms. The name ‘twig
scorch’ is suggested for the new disease on account of the withered
or scorched appearance of scattered twigs on the tree, which give
the impression of being charred by fire. The spores of the fungus
are larger than those of the withertip organism and were referred
to the genus Macrophoma, the name M. destruens being provisionally
proposed, but without diagnosis.

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396

The excision of diseased branches one foot below the grey, dead
section and the application of Bordeaux mixture are recommended.

Eaton (B. J.). Report of the Director of Agriculture, Federated
Malay States and Straits Settlements, for the year 1921, 14
pp., 1922.

The report contains the following references to subjects of
phytopathological interest. The two principal diseases of rubber
under investigation during the year were pink disease (Corticium
salmonicolor) and mouldy rot (Sphaeronema fimbriatum), the latter
being closely correlated with heavy rainfall and damp conditions.
Systematic treatment with disinfectants for the control of mouldy
rot is being carried out, but owing to the neglect of small holdings
consequent upon the low price of rubber the disease has become
very widespread. Patch canker (Phytophthora sp.), thread blight,
brown root disease [see this Review, 11, p. 291], and Sphaerostilbe
repens were also observed. Somes lignosus was prevalent on
certain Chinese estates, especially where tapioca or gambier was
interplanted with the rubber. Dry rot (Ustulina zonata) was of
fairly frequent occurrence and wet rot (Fomes pseudoferreus) caused
a good deal of damage on two estates in Negri Sembilan.

Black stripe (Phytophthora faberi) occurred near Katjang and in
the Temerloh and Jelebu districts, but the treatment of this disease
has now become a matter of routine. In Pahang the infected areas
have been greatly reduced owing to the cessation of tapping.
Brown bast has also been kept in check by the adoption of more
conservative methods of tapping. Experiments in heavy tapping
conducted on the Castleton Estate have shown a correlation between
such tapping and the incidence of the disease [see this Review, ii,
p. 178] and have also indicated that certain trees, for some
unknown reason, remain immune in spite of these methods of latex
extraction.

A new species of Helminthosporiwm attacking branches of badly
grown rubber trees has been observed and also a branch canker
not yet investigated. Several fungi, including a species of Mucor,
Pestalozzia palmarum, and Diplodia were isolated from leaves
arising from buds on three year old bud-grafted stock. The use of
stocks which have attained this age appears to result in a weakness
of the bud which predisposes it to disease.

Investigations on the bud rot disease of coco-nuts were continued.
The disease is not epidemic in Malaya and may be due to several
causes, including previous attacks of beetles. A bleeding disease,
apparently different from that occurring in Ceylon, was fairly
prevalent. Several fungi were isolated and are under study.
Premature nut-fall was also studied.

Young African oil palms suffered from an affection of the heart
leaves which could not be assigned to any definite agency and its
relation to the coco-nut bud rot is being investigated.

LEVINE (M.). Studies on plant cancers. V. Leafy crown galls on
Tobacco plants resulting from Bacterium tumefaciens
inoculations.—Phytopath., xiii, 3, pp. 107-116, 2 pl., 1923.

The author distinguishes two types of leafy crown galls on the

397

tobacco plant produced by Bacterswm twmefuciens. The first type
results from the imoculation of the midrib of the leaf and of the
internodes of the stem. The growth of the gall is at first normal,
but after two to three weeks diminutive leafy shoots develop, the
leaf structures first appearing as small, greenish-white protuberances.
The leafy crown gall appears to arise by a secondary process of
differentiation; just as the small embryonic cells of the normal
crown gall later become differentiated into various mature tissues,
so those of the leafy crown gall become leaves and often modified
stems and roots. The leafy crown galls on the stems become much
larger than those on the midribs and the embryonic leaves which
appear on them more numerous and larger; otherwise they are
much the same.

The second type of crown gall is caused by the inoculation of
stems at the axillary buds and is termed axillary leafy crown gall.
It may be distinguished as a comparatively elongated, branch-like,
axillary growth, which is undoubtedly the result of an abnormal
development of the axillary bud. These structures are never so
well developed as in the axillary shoot arising from a decapitated
stem but are dwarfed, fasciated, and abnormal in appearance.
Sometimes, however, inoculations of the axillary buds do not
produce leafy shoots but large globular galls and the development
of the dormant buds may be partially inhibited.

Inoculations at axillary buds of decapitated plants result in
malformed, branch-like growths, generally stunted and with small,
pale green leaves. The added stimulus of the decapitation, there-
fore, does not increase the size of the axillary leafy crown gall.

JOHNSTON (T. H.). Biological control of the Prickly Pear pest.—
Scient. Australian, xxviii, 2, pp. 24-26, 1923.

The governments of Australia, Queensland, and New South
Wales have co-operated financially in a scheme of investigations
for the control of the prickly pear [Opuntia] by means of its
natural enemies, including insects, fungi, and bacteria. Eight
distinct kinds of fungi known to cause disease in prickly pears
either in North or South America were obtained by the chief
laboratory of the Prickly Pear Board, near Brisbane, only one of
which (Gloeosporium lunatum) has hitherto proved to be of any
value. Under certain conditions, namely, combined heat and
moisture such as a Queensland summer furnishes, this fungus may
set up a serious decay in Opuntia joints. So far it has not
attacked any of the other plants tested.

While in Florida, the writer discovered a bacterial disease, the
causal organism of which has been isolated and proved capable of
causing a very virulent disease among all the species of prickly
pear naturalized in Queensland and New South Wales. Attempts
are in progress to secure the transmission of the bacterial disease
from joint to joint (an essential to effective control) by the agency
of moth borers (Melitara sp.) and the Mimorista moth.

Judging from the laboratory results, it appears that a complex
of organisms has now been established in Australia which may
ultimately secure the complete contro] of the prickly pear menace.

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398

NosLe (R. J.). Studies on Urocystis tritici Koern., the organism
causing flag smut of Wheat.—Phytoputh., xiii, 3, pp. 127-139,
1 pl., 2 figs., 1923.

Studies on smuts have often been hampered by the difficulty of
securing a vigorous germination of the spores and the present
investigations with Urocystis tritici were directed to determining
the conditions necessary for this to take place.

After many fruitless trials, it was found that spores which had
been presoaked in water for several days would germinate pro-
fusely after the addition of small quantities of the tissue of wheat
seedlings.

The stimulation by the latter is greater when the spores have
been presoaked for 3 or more days than when it is added simul-
taneously with them. Dry spores sown on wheat plant infusions
failed to germinate. A table is given showing the germination
after various periods of presoaking before the addition of wheat
tissues, a period of 4 days giving 90 per cent. germination whilst
28 days gave only 2 per cent. All portions of young wheat
seedlings or even the whole uninjured wheat seedling were equally
powerful as stimulants. There was no difference between tissues
irom einkorn, emmer, and spelt types nor from wheat susceptible
or resistant to flag smut, and whilst wheat plant tissue was the
most effective, tissues of rye, barley, oats, flax, and various grasses
also stimulated germination to some extent. Autoclaved infusions
and the distillates from water extractions of wheat seedling tissue
also gave satisfactory results, showing that the stimulatory sub-
stances are volatile. The temperature relationships of U. tritzez
were found to be largely influenced by the presoak treatment the
spores had received. For instance, a presoak period of 5 days at
20° C. gave good germination, but an additional presoaking for 30
hours at 27-5° C. reduced the germination to a trace. In distilled
water spores incubated at temperatures varying from 7° to 27°C. for
8 days germinated in the following order on the addition of wheat
tissue :—first at 18°C., then at 20°, 12°, and 7°, none occurring
at 27°C., but spores presoaked at 20°C. for 6 to 8 days even
germinated at 29°C. (and in one case at 32°C.) In another test,
spores presoaked 6 days at 20°C. germinated well at 5° (and in
one case at 0°) and growth was greatest at 24° C. although there
was little difference in percentage germination between 18° to 27° C.
Spores which have not been presoaked germinate most quickly
about 18°C. When kept above 24°C. for some time, they respond
less readily.

With regard to oxygen, spores of U. tritici germinated almost
as readily and practically to the same extent when totally sub-
merged as when sown on the surface, on receiving a suitable
stimulus after presoaking. The promycelia of the former tended
to become abnormally elongated before producing sporidia.

In germinating, the promycelium normally reaches 20 to 30 by
5 before the protuberances (usually 2 to 4 in number) which
finally develop into sporidia are formed at the tip. The sporidia are
cylindrical in shape and about 30 by 5, in size. Various irregular
germinations were observed consisting chiefly of fusions or elonga-
tions of the sporidia or promycelium into long, thin germ-tubes.

399

In discussing the results obtained, the author points out that soil
may be heavily infected with spores of U. tritici and a clean crop
sometimes grown, while under other conditions a relatively small
amount of inoculum may cause a serious outbreak. This apparent
capriciousness would appear to be due to the operation of various
factors,—soil moisture, soil temperature, soil aeration, and the
presence of a stimulatory substance—and probably these factors
must operate in proper sequence to cause the development of flag
smut epidemics.

THOMPSON (N. F.). Kill the common Barberry with chemicals.—
U.S. Dept. Agric. Circ. 268, 4 pp., 3 figs., 1923.

Of the several chemicals tested for the eradication of barberry,
the best results were obtained by the use of salt and of a solution
of arsenite. The former, either crushed rock salt or ordinary
ground salt, should be piled in a dry state on the soil at the centre
of the barberry bush, where it usually remains for several months,
slowly dissolving. Ten pounds of salt are generally sufficient to
kill an average bush, i.e., with a crown not over 12 inches in
diameter. Smaller bushes may not need so much, but no bush
should receive less than five pounds. The dose should be pro-
portionally increased for larger bushes. The bush may be treated
at any time of the year and may either be cut down or left
standing.

The commercial sodium arsenite solution tested contained the
equivalent of 8 lbs. of white arsenic (As,O,) per gallon | American].
For use it was diluted with 40 to 50 volumes of water, two gallons
of the dilute solution poured into the centre of the plant so as to wet
the base of each stem usually killed an average bush as defined above,
but less than 14 gallons should not be used even for small bushes.
The best time for applying sodium arsenite is between the lst May
and the 30th September and the bush should be left standing.
The soil immediately round the bush becomes sterilized as a result
of both treatments, but this effect is of shorter duration with sodium
arsenite than with salt.

Womit soll man beizen? [Which are the best seed disinfec-
tants ?|—Nachrichtenbl. deutsch. Pflanzenschutzdienst, iii, 3,
p. 17, 1923.

For the control of bunt of wheat (Z%lletia levis) [and 7. tritici]
the following fungicides are recommended by the German plant
protection service. Weizenfusariol, obtainable from W. C. Fikent-
scher, Marktredwitz, Bavaria; germisan (Saccharinfabrik, Magde-
burg); formaldehyde and fungolit (Holzverkohlungsindustrie
A. G., Constance, Baden); uspulun (F. Bayer & Co., Leverkusen) ;
kalimat (L. Meyer, Mainz); and Praparat 23—Halle (Phytopatho-
logical Experiment Station, Halle-an-der-Saale). Fungolit- and
the two last-named preparations have been tested during 1922
only.

Stripe disease of barley [ Heliminthosporiwm Magi cenid can be
controlled by germisan and uspulun, and loose smut of oats [ Ustilago
avenae| by formaldehyde, germisan, sublimoform (Fikentscher,
Marktredwitz), fungolit, and kalimat.

400

Loose smut of wheat and barley [Ustilago tritici and U. nuda]
can only be controlled by immersion of the seed for ten minutes in
hot water (50° to 52°C.). Immediately after steeping, the seed
must be rinsed in cold water or spread out to cool. The quantities
required for steeping 10 ewt. of seed wheat are 200 litres, barley
300 1., and oats 400 J. The seed should not only be sprinkled with
the liquid but immersed in it. Wheat must be thoroughly stirred
so that the uninjured bunt balls may rise to the surface and be
removed by scooping off. Granary floors and grain sacks should
also be disinfected to prevent subsequent infection of the seed.

Hecke (L.). Neue Erfahrungen iiber Mutterkornkultur. [New
experiments in the cultivation of ergot. ]— Wiener landw. Zeit,
Ixxiii, 1-2, p. 3, 1923.

The author continued during 1922 his experiments on the culti-
vation of ergot for medicinal purposes [see this Review, 11, p. 114).
The work of infection was simplified by the use of a Perolin spray,
and the total yield of ergot in 1922 was 527 kg. from one hect. of
summer rye, or almost twice as much as in 1921. The average
number of sclerotia per ear was 4-5, as against 3 in 1921. The
sclerotia were normally developed, smaller and more symmetrical
than those previously obtained from the winter rye. The yield of
ergot from crosses between Secale montanwm and rye was 370 kg.
per hect., without any artificial stimulus to blossoming or artificial
infection.

On the whole, the cultivation of ergot, which is at present fetching
increasingly high prices, appears to be well worth while.

SamMpsoN (KATHLEEN). Seed treatment for smut in cereals.—
Bull. Welsh Plant Breeding Stat. Aberystwyth, Ser. C., 3,
pp. 46-54, 1923.

The author discusses briefly the well-known disadvantage of seed
grain disinfection with copper sulphate and formalin, a treatment
which often results in a serious reduction of germination when the
treated seed is sown in dry soil or stored for some time before sowing.
Recently Harrington [Journ. Agric. Res., xxiii, 2, p. 79, 1923] has
shown that the practice of presoaking with a view to lessening
formalin injury may itself cause a reduction of germination under
certain conditions. It is, therefore, evident that a dry method of
seed disinfection would be of value, and experiments are described
giving the results of trials with dry copper carbonate against bunt
of wheat [Tilletia tritici] and covered smut of barley [Ustilago
horde?).

The grain was mixed with smut spores, and treated with 3 oz.
powdered copper carbonate per 4 bushel of grain, then stored for
three weeks before sowing. There was no injury to germination
or yield and very satisfactory control of the two smuts was obtained.
The cost was, however, considerable (sixpence per bushel against
one halfpenny and one penny for formalin and copper sulphate
respectively).

Comparative tests with copper sulphate (23 1b. to 10 galls. water)
and formalin (1 in 320) for the control of the above diseases as well
as loose smut of oats [Ustilago avenae] showed a reduction in

401

germination and yield when the seed was kept for three weeks
before sowing. Copper sulphate followed by dusting with finely
powdered slaked lime was better than the others, but still reduced
the yield by 9 per cent. with wheat and 3 per cent. with barley, as
compared with no reduction after copper carbonate and 27 and 10
per cent. respectively after formalin. Oat smut was completely
controlled by formalin, but the yield was reduced by 3 to 10 per
cent.

SAMPSON (KATHLEEN) & Davigs (D. W.). Incidence of fungus
diseases on Oat varieties in the seasons 1921-22.—Bull.
Welsh Plant Breeding Stat. Aberystwyth, Ser. C., 3, pp. 55-57,
1923.

The incidence of fungous diseases on different varieties of oats
during the seasons of 1921 and 1922 is recorded. Crown rust
(Puccinia loli) was practically absent in the former year when
the harvest was unusually early. In 1922 the varieties most
severely attacked were Orkney strigosa, Potato, Victory, and
Yielder, Black Tartar, and American Sixty Day being relatively
free from the disease.

Black rust (Puccinia graminis) has not been recorded on oats in
the Aberystwyth experimental plots since 1920.

Mildew (Erysiphe graminis) was abundant in July 1921 and
1922, no variety showing any marked degree of resistance.

Loose smut (Ustilayo avenae) occurred on 31 different varieties
during the period 1920-22. Among those most severely affected
were Radnorshire Sprig, Ceirch du Bach, and Potato.

Covered smut (U. levis) was recorded in the trial grounds only
on Avena nuda var. chinensis, A. strigosa subsp. glabrescens, and
A. strigosa subsp. orcadensis. A preliminary inoculation experi-
ment with U. /evis on a number of varieties susceptible to U. avenue
gave negative results. The range of varieties susceptible to U. levis
in Britain is believed to be limited.

Stripe (Helminthosporium avenae) occurred on 41 varieties of
spring sown oats in 1921, Record, Yellow Naesgaards, Leader, and
Goldtinder being the most severely affected, while Algerian sterilis
was immune. In 1922 the disease was unimportant.

Halo blight (believed to be identical with the American disease
caused by Bacteriwm coronafaciens) was especially severe in 1921
on Fulghum, an autumn sown variety, a few well-known spring
oats, however, also being affected. In 1922 the autumn varieties
escaped, but the disease was very severe on Odal, Black Tartar,
Orion, and other spring varieties.

ALLEN (RuTH F.). A cytological study of infection of Baart and
Kanred Wheats by Puccinia graminis tritici—Jowrn. Agric.
Res., xxiii, 3, pp. 131-151, 6 pi., 1923.

An investigation of the process of infection of Baart (susceptible),
Kanred (very resistant), and Mindum (semi-resistant) wheat seedlings
by three strains of stem rust (Puccinia graminis tritict) has been
conducted at Berkeley, California.

From inoculations with uredospores on Baart, and to a limited
extent on Mindum seedlings, it was found that the germ-tubes take

13

402

the nearest route to the stomata; the protoplasm is massed toward
the growing tips leaving the older parts almost empty. On reaching
a stoma the end of the germ-tube swells out to form an appres-
sorium in the stoma aperture, a cross wall cutting off the now
empty germ-tube which soon disappears. Within 24 hours of
inoculating, many appressoria may be produced.

From the appressorium a blade-like wedge is forced through the
stomatal slit, and this swells up inside to form the substomatal
vesicle into which the cell contents pass leaving the collapsed
appressorium outside. One or more hyphae are given off from the
vesicle, and when the tip of one of those meets a host cell, and
growth is forcibly checked, a haustorium is usually initiated. The
hypha swells up, its contents become concentrated near the tip,
which becomes closely applied to the wall of the host cell, and soon
after a septum cuts off the haustorium mother cell whose contents
are very dense. When the fungus is ready to enter, a minute pore
is formed which allows the osmotic membranes of host and parasite
to come into contact. The osmotic pressure in the latter is probably
higher than in the former, and the substance of the haustorium
mother cell pushes through into the host cell whose protoplast is
forced inwards. The young haustorium consists of a dense ball of
deep staining, fungous cytoplasm and a narrow neck joining this
ball to the parent cell. Later the haustorium expands. Frequently
the cell below the haustorium mother cell gives off one or more side
branches which continue growth.

On Kanred seedlings, the process is similar, but very few (about
10 per cent.) of the appressoria grow through the stomatal slit to
form mycelium in the host, the stoma being slender and the aperture
small. Another strain of rust (P. graminis tritici 11) to which
Kanred is less resistant, gave on the whole a larger number of
successful entries (about 20 per cent.). When entry has been
observed, the fungus passes in at one end of the stomatal slit and
swells up inside. Haustorium formation commences in normal
fashion, but with the entrance of the fungus into the host cell
abnormal changes begin. The haustorium mother cell may collapse
and shrink away from the host and a small, red-staining spot on
the host cell wall mark the attempted point of entry. Thé appear-
ance of sections suggest that some substances diffuse out from the
host cell, disorganizing the haustorium-producing cell, and some-
times plasmolysing the cell below it also. Changes in the host cell
are equally marked, an increase of turgor being rapidly succeeded
by collapse and death. Walls of host cells adjacent to this dead
cell become markedly thickened and thereby probably prevent the
diffusion of substances to and from the diseased ceil. A fungus
which has been checked in this way once may still retain enough
vigour to grow and may make a number of attempts (up to 6) to
produce a haustorium. In some cases the reaction between host
and parasite is more sluggish than has been described and the
fungus may succeed in producing a haustorium thereby gaining
food to grow on to the next cell before the first invaded cell dies.
This process may be repeated a number of times, resulting in a
suecession of dead host cells (up to 24) and an ever weakening
advance of the fungus. - When a haustorium is formed, at

403

first it usually possesses the normal cytoplasmic envelope formed
from the host cytoplasm, but in the older haustoria this is usually
lacking, possibly because some substance diffuses from the hausto-
rium which either destroys or repels the cytoplasm of the host cell.
In old material all traces of the mycelium disappear, except the
initial hypha at the stoma, but just how this happens is not clear.

In discussing her results, the author points out that Kanred
possesses three means of defence against rust: (1) stomata which ex-
clude all but a few germ-tubes [see this Review, ii, p. 359], (2) heavy
contact walls adjoining pathological cells, and (3) a true immunity.
She finds little support for the ‘starvation’ theory of immunity,
as although the fungus exhausts itself in unsuccessful attempts to
enter into food relations with the host, yet the failure is due not
so much to lack of food as to a specific reaction set up in the host
which destroys the fungus. As long as no haustorium is initiated,
host and parasite remain unharmed, but when they come into
contact each appears to give out substances harmful to the other.
These observations are in line with the view that immunity is due
to the formation of specific toxins and antitoxins as in the case of
animal diseases.

A bibliography of 30 titles is given.

HILTNER (E.). Havrens graflecksjuka och dess botande med man-
gan. |The grey speck disease of Oats and its control with
manganese. |—Landtmannen, vii, 9, pp. 133-185, 2 figs., 1923.

The results of laboratory experiments with various mineral
nutrient solutions have shown that the grey speck disease of oats
[see this Review, i, p. 417] is promoted by the presence of potassium
chloride, potassium nitrate, and calcium nitrate (singly or in com-
bination). The injurious effects of these minerals in water cultures
are counteracted by the addition to the solution of magnesium
phosphate or potassium phosphate (or both). When KH,PO, and
Ca(NO.), are both present in the solution, grey speck does not occur
but the plants suffer severely from chlorosis. A series of field tests
indicated that oats are particularly liable to attack on heavily
limed peat soils and on calcareous soils with an abundance of humus.
Grey speck does not occur on sandy or clay soils even after the
application of lime. The influence of light and shade on the
development of the disease was also studied. Plants growing in
the shade were found to be much more severely attacked than those
in sunny situations.

It was shown by further tests that the disease could be completely
controlled by the application of manganese salts together with
potassium nitrate. This combination also ensures a higher yield.
By expediting maturity and thus eurtailing the period of growth
(the critical stage in grey speck disease) manganese salts reduce the
chances of attack to a minimum.

SAvyasTano (L.). Lavoro della Stazione durante il periodo 1915-—
20. [Work of the Station during the period 1915-20.]—Anu.
R. Staz. Sper. di Agrwmic. e Fruttic. in Acireale, vi, pp. 125-
138, 1922.

Amongst the plant diseases studied at this Experiment Station

SS ee

404

in Italy a root rot of sour fruit trees, which brings about their
rapid decay, constitutes a serious menace to the Sicilian citrus
industry. Locally known as ‘cagna’, the disease is due partly to
pathogenic agents—not all of which are as yet fully determined—
and may occur either sporadically or in an intensely epidemic form,
varying from year to year in accordance with weather conditions.
The following factors tend to aggravate the trouble: (1) defective
aeration due to compact and water logged soils; (2) reduced powers
of resistance of the bitter orange brought about by attempts to
accelerate and improve its yield by forced cultural methods ; (3) close
planting, which prevents solar action on the soil and helps to main-
tain excessive humidity, thus favouring parasitic growth and up-
setting the trees’ economic balance; (4) excessive manuring at long
intervals which has the same effect and lowers vitality; (5) excessive
and badly regulated irrigation; (6) the practice of ‘ verdello’ [‘ ver-
delli’ are lemons forced to maturity before the ordinary crop by
special methods of irrigation] carried to excess in the lemon groves.

While these causes can undoubtedly be successfully met by
appropriate cultivation, the question arises whether, and to what
extent, the bitter orange could be replaced with advantage by some
other stock more resistant to root rot. As under favourable soil
conditions the bitter orange has so far proved sufficiently resistant,
and its cultivation has been profitable, the Station has in these
cases been content for the present to recommend cultural remedies,
which experience has shown to be effective in keeping the disease
within very narrow bounds. Experiments with stocks other than
bitter orange are being carried out, exotics, however, being excluded
for fear of introducing diseases, such as citrus canker, still unknown
in Italy.

SAVASTANO (L.). Contributo allo studio del male dello scopaccio
negli Agrumi. [Contribution to the study of ‘witches’
broom’ on Citrus trees.|—Ann. R. Staz. Sper. di Agrumie.
e Fruttic. in Acireale, vi, pp. 119-124, 6 pl., 1922. .

Witches’ broom disease of citrus was observed by the author for
the first time in 1914 on a few isolated trees in Palermo. Although its
occurrence in this district can be traced back for at least fifty years,
the trouble is so rarely met with that no serious attention has been
paid to it. A similar deformation has been observed on forest and
ornamental trees, amongst the latter being cypress and Broussonetia
papyrifera. Whereas witches’ brooms are comparatively frequent on
forest trees, and develop at times with great intensity, cultivated fruit
trees are rarely attacked, and it is thought that this immunity may
be due to pruning. On the other hand, in forest trees the trouble
appears to be contined to one branch only, while in citrus trees the
whole tree becomes invaded. The species most subject to, the
disease is the lemon, but the comparative immunity of the orange
may be simply the result of its less intense cultivation in Sicily.

Normally, the disease affects trees of a somewhat advanced age,
the youngest recorded case being a tree that had been grafted six
years before. It develops slowly, but the rate of progress is faster
in some years than in others. Once established in a branch it
proceeds to invade others until after some years the whole tree is
affected.

405

At the beginning, the foliage shows the symptoms of chlorosis,
and the individual leaves sometimes tend to become elongated. The
cortex dries up and is detached with difficulty, and at this stage
some degree of sterility may result. On the branches the begin-
nings of the disease are marked by the formation of hypertrophied
tubercles in many of the buds, which if able to produce shoots at
all, give only very small ones. The apical portion of the affected
branch is also atrophied. During the second stage the hypertrophy
becomes intensified and many of the buds are killed by constriction,
while the apex and lateral shoots produced by an affected branch
are normally atrophied but may be hypertrophied. On the hyper-
trophied twigs, the leaves are generally small and malformed and
any lateral branches borne are weak and stunted. The third phase
is the formation of the ‘broom’ by the production of single twigs
from one or more of the swollen buds and the development of
secondary lateral branches, more or less crowded together, on these.
This period of vigour is followed by the gradual decay of the twigs
forming the ‘broom’, which wilt and become atrophied. Lastly,
twisted branches with large sterile tubercles are left, which give
the tree an enfeebled appearance.

Lemons on diseased trees develop in a characteristic manner; the
navel becomes somewhat elongated and the fruit itself, from being
ovoid or subrotund assumes an elongated oval form, while the
smooth rind becomes roughened. There is no great difference in
the acid and sugar content of lemons from healthy and diseased
trees, but an increase in acid and a decrease in sugar become more
noticeable as the disease progresses, as is usual ‘in troubles affecting
citrus trees.

The cause of this malformation is unknown, and the only proved
remedy is the cutting away of affected branches as soon as they are
noticed.

JANINI JANINI (R.). The chief diseases and pests of the Orange
and Lemon groves in Spain.—Jitern. Rev. of the Sci. and
Pract. of Agric., N.S., i, 1, pp. 61-73, 2 pl., 1923.

The chief fungous diseases of citrus trees and fruit in Spain are
said to be those caused by the following fungi :—A garicus citri Inz.
(‘mal de cafia’), Polyporus obliquus Fr., Meliola citri Br. (‘mal
de ceniza’), Meliola penzigi Sacc. (Fumago vagans Pers.), Clado-
sporium fumago Link, Dematiwim monophyllum Ris., Capnodium
citrt Mont., Morphea citri Catt. (‘negrilla’ &¢.), Physalospora
citricola Penz., Sphaerella gibelliana Pass., Melanomma mediwm
Sacc., Pleosphaeria hesperidum (fruit spot), Sphaerium woljfen-
sterniani Kiihn (‘mal de goma’ &c.), Aposphaeria sepulta Penz.,
Colletotrichuim gloeosportwoides Penz., Oospora hyalinula Saec., Peni-
cllium glaucum Link., P. digitatuin Sace., Botrytis vulgaris Fr.,
Echinobotrywm citri Gar., Cladosporiwvm herbarum Link., Fusariwm
limonis Br. and Rhizoctonia violacea Tul.

Of these the most dreaded are ‘negrilla’ and ‘mal de goma’
(gummosis). The latter is usually controlled by cutting the main
root of the tree and uncovering the large roots to a distance of 25 em.
from the trunk. A circular trench is dug round the tree to prevent
the irrigation water reaching the trunk. Another method is to apply

eS

406

powdered iron sulphate every three, four, or five years. The chemical
is spread on the soil at the rate of 600 to 1,200 kg. per hectare and
dug in like other fertilizers.

The chief insect pests are described in some detail and a biblio-
graphy of Spanish references is appended.

BarTHOLOMEW (E. T.), BARRETT (J. T.), & Fawcerr (H.S.). Internal
decline of Lemons. I. Distribution and characteristics.—
Amer. Journ. of Botany, x, 2, pp. 67-70, 1 pl., 1928.

The term ‘ internal decline’, as used in the present article, includes
‘blossom end decay’, ‘tip deterioration’, ‘yellow tip’, ‘dry tip’,
and other local names applied to the same trouble. The indications
are that the disease, which is particularly prevalent in the hot inland
valleys of southern California, is increasing in severity. All varieties
of lemon appear to be more or less susceptible, and trees of any age
from three to fifty years may be attacked. The highest percentage
of infection is usually found in the so-called ‘tree-ripe’ fruit, i.e.,
the lemons which remain on the tree until they have attained their
mature yellow colour, but in severe cases the green fruit may also
be seriously damaged. The disease may be found at almost any
time of year from June onwards.

The external symptoms of the disease are by no means infallible,
but in most cases the development of an intensive orange-yellow
colour at the stylar end of the fruit denotes the initial stages of an
abnormal breakdown of the internal tissues, and at a later stage, in
ripe fruit, a depression often appears in the rind at the stylar end.
The internal symptoms, which vary considerably in green, silver,
and ripe fruit, consist of the collapse of the parenchymatous cells
at the stylar end, the clogging of the vessels in the peel at this end
with a pinkish to rust-brown deposit of gum, and a loss of water
from the neighbouring tissues, including the cells of the fruit pulp
below the apex. This loss extends gradually deeper in towards
the centre of the fruit and may ultimately result in the drying out
and collapse of the pulp involving a third or half the fruit at the
distal end.

BaRTHOLOMEW (E. T.). Internal decline of Lemons. II. Growth
rate, water content, and acidity of lemons at different stages
of maturity.— Amer. Journ. of Botany, x, 3, pp. 117-126,
1923.

A series of experiments was conducted at Corona, Upland, and
Riverside (California), on Eureka lemon trees of varying ages, to
determine the possible bearing on the etiology of internal decline
[see last abstract], of (a) the rate of increase in size, as influenced
by climatic and seasonal changes and the time of year at which the
fruit is set, and of (}) the increase in acidity and water content of
the fruits at different stages of development. The results of the
tests, details of which are given, showed that, while the Eureka
lemon tree tends to a continuous production of new fruit, the age
of the tree and climatic and soil conditions render such production
more or less seasonal, especially in the inland regions.

Climatic and seasonal factors determine the growth rate of the
fruits some of which mature in seven or eight months, while others

407

on the same tree require fourteen months. The time of the year
when the fruit sets and the position on the tree also affect the
growth rate. Lemons may actually decrease in size while still
attached to the tree in consequence of the withdrawal of water by
the leaves, and this may result in the collapse of a portion of the
tissue in the stylar end of the fruit. The lemon fruit in fact acts
as a water reservoir for the leaves. The wilting coefficient of the
soil as indicated by the leaves is not a reliable criterion as to the
adequacy of the water supply to the fruit. The water contents of
the two ends of the normal lemon are practically identical. The
water content increases rapidly until the lemon has attained a
diameter of about 3-8 em., and then more slowly until the fruit
reaches maturity. The size of the lemon is not necessarily propor-
tional to the percentage of water it contains. In the young fruit
the percentage of water depends to a considerable extent on the
available supply of water to the roots. The variation in the water
content of the mature lemons under observation in the experiments
ranged from 88-20 to 92-14 per cent.

The total acid content of the lemon increases rapidly with
increasing size, but there is a very slight increase in the true
acidity of the juice after a diameter of 3-8 cm. has been attained.
The examination of a large number of normal lemons showed that
in spite of some wide variations, the average degree of acidity was
substantially the same in the stylar and stem ends. Ripe lemons
of approximately the same age and size exhibited a comparatively
wide range of acidity, the average for all tested being P,, 2-31.

Winston (J. R.) & Bowman (J. J.). Commercial control of Citrus
melanose.— U.S. Dept. of Agric. Circ. 259, 8 pp., 1928.

As a result of numerous spraying experiments and of field
observations by commercial growers, the authors state that, under
Florida conditions, melanose of citrus fruits (Phomopsis citri) is
readily controlled by one or two applications of standard 3-3-50
Bordeaux mixture plus one per cent. oil in the form of emulsion ;
in an average season the treatment should be completed by 5th May.
Comparative tests with other preparations showed that weaker
Bordeaux mixture and other weak copper sprays are not as effective
as the one recommended. The formula and instructions for the
preparation of the mixture are essentially the same as previously
described [see this Review, ii, pp. 363 and 364] except that the oil
emulsion recommended is made by boiling 2 gall. paraffin oil, 1 gall.
water, and 2 lb. fish oil soap together and pumping the hot liquid
into another vessel and back again. Sulphur sprays as a class and
copper or sulphur dusts have not thus far proved satisfactory for
the control of melanose. Thorough pruning of the dead wood
(which has been recommmended for a number of years as a means
of controlling melanose in a normal mature grove) has not been
found commercially practicable in view of the high cost and slow-
ness of the work, and careful experimental trials made in 1921 and
1922 did not give satisfactory results as little or no control of the
disease was etfected. Prunings on the ground and fallen fruit did
not appear to be a source of melanose infection. When melanose is
controlled, stem end rot of the fruit is reduced. Treatment against

408

melanose should be followed by spraying against insect pests and
other fungous diseases.

Sma (W.). The diseases of Coffea arabica in Uganda.— Uganda
Dept. Agric. Cire, 9, 22 pp., 1923.

This account of the principal fungous diseases of coffee in Uganda
has been prepared mainly for the use of planters and agricultural
officers. Technical details have been omitted as far as possible, the
symptoms of the diseases and the life-histories of the causal organ-
isms being briefly described in popular language. The amelioration
and prevention of the local diseases of coffee are much more feasible
than their cure. The suggested control measures are therefore
based mainly on an improvement in the environment of the trees,
the general condition of which is too frequently below par in
Uganda.

Coffee leaf disease (Hemileia vastatrix) is common on Coffea
arabica, especially in the absence of shade. Direct control of the
disease by spraying is, in the writer’s opinion, impracticable in
Uganda. The cost is prohibitive and the results uncertain. In-
direct control measures include the planting of the trees in small
blocks isolated by wind-breaks, arranged in such a way that the
prevailing winds sweep them crosswise rather than lengthways;
wide planting; the burying of fallen diseased leaves; the selection
of dry sites for nurseries, and the provision of suitable shade.
Overbearing should be prevented by stripping. Some system of
pruning to lighten overburdened trees is necessary, and it is
hoped that the multi-stem experiments now in progress will be
continued.

The leaf spot and berry blotch due to Cercospora coffeicola also
occurs principally in the open and may be largely controlled by the
provision of shade trees. The destruction of infected leaves and
berries and a series of spray applications with Bordeaux mixture
while the berries are ripening are also recommended.

Brown blight of leaves and berries (Colletotrichum coffeanum =
Giomerella cingulata) may be adequately controlled by due atten-
tion to shade and other cultural methods.

Sooty mould (Caupnodium brasiliense) is in itself more unsightly
than harmful and is important chiefly as indicating the presence of
the scale insects with which it is associated. The fungus is depen-
dent on the honey dew secreted by these insects and disappears when
they are destroyed. Attacks of sooty mould have been infrequent
of recent years.

Defective beans, usually termed ‘lights’ or ‘floaters’, may be
due to any one of the following causes, or to a combination of
several: Hemileia leaf disease, prevalence of die-back, Colletotri-
chum blight, Cercospora blotch, variegated bug, or unfavourable
weather conditions during ripening. The variegated bug has
been proved to be implicated in the introduction of a species of
Phoma into the tender tissues of the young beans by means of
spores carried in or on the beak with which it punctures the
‘cherries’. The fructifications of the Phoma can afterwards be
found on the cured beans, where their presence and development
add considerably to the direct harm caused by the insect. The

409

‘provision of shade and attention to other cultural measures will
greatly reduce the proportion of defective beans.

Anthracnose of branches may be due to a variety of causes
besides the direct attack of the fungus Colletotrichwm coffeanum,
which was conclusively proved in 1919 to be mainly saprophytic.
Hemileia leaf disease frequently leads to the dying back of branches,
while insect attacks and sun scorch are also often responsible. The
use of the terms ‘large scale die-back’ and ‘small scale die-back’
has given rise to some confusion, which will in future be avoided
by referring to the former as die-back proper and to the latter as
anthracnose.

Die-back proper is the result of a disturbance in the normal
physiological balance of the plant and is confined to the older trees.
Its prevalence in Uganda is believed to be largely due to the errors
of cultivators which accompanied the commercial rise of coffee-
growing from 1910 onwards. The choice of unsuitable sites, and
the neglect of pruning and other cultural operations resulted in
serious losses. To-day the disease is less in evidence on account of
the gradual spread of scientific knowledge, and it should be possible
to reduce it to a minimum by proper care. The selection of healthy
seed, thorough weeding, mulching and fertilizing, and the provision
of shade are among the most important preventive measures.
Hemileia is an important factor in the production of die-back, and
the measures recommended for the control of the former will con-
tribute to the prevention of the latter.

Witches’ brooms, the cause of which is unknown and may
possibly be an insect or a parasitic fungus, are uncommon on coffee
in Uganda. Affected branches should be burnt.

Brown root disease (Fomes lamavcensis) [see this Review, ii, p. 291]
is somewhat rare, being generally restricted to isolated young trees.
The degeneration which it causes is sometimes so gradual as to be
imperceptible until the collapse of the affected trees in a storm re-
veals the decay of the lateral roots. The following preventive
measures are recommended: (1) isolation of the infected area by a
trench one to three feet in depth ; (2) removal of the diseased trees
and all broken fragments of roots ; (3) disinfection of the soil by ex-
posure to sun and air and the working in of lime ora soil fungicide.

Root rot (Armillaria mellea) produces symptoms similar to those
of brown root disease and may be controlled in the same manner.
The scarcity of both these diseases on Uganda coffee is largely
attributable to the fact that elephant grass land rather than forest
was used for planting.

Mealy bug root disease (Pseudococcus citri and Polyporus coffeae)
is very prevalent in old native gardens, the mealy bug (which the
author regards as the dominant and earlier partner in the associa-
tion) occurring on a number of indigenous crops. Polyporus coffeae
has not yet been found as an independent parasite of coffee, and is
not known to occur on any other plant or in any country except
Uganda. Apart from the insect, therefore, the fungus appears to be
only very weakly, if at all, parasitic. Further investigations, how-
ever, are necessary to determine the exact nature of the relations
between the two.

8 POS a EE TOA

410

ScHIKoRA (F.). Ueber die Krebspest und ihren Erreger, Aphano-
myces magnusi Schikora, [On the Crayfish plague and its
cause, Aphanomyces magnusi Schikora.]|—Verhandl. Bot.
Vereins Prov. Brandenburg, \xiii, pp. 87-88, 1922.

This paper, read before the Botanical Society of the Province of
Brandenburg in September 1920, deals with the results of an in-
vestigation lasting many years into a disease affecting crayfish.
The crayfish fisheries of Germany are of considerable importance,
the yearly value of the catch in German waters amounting to
100,000,000 marks [then worth about £800,000]. The disease itself,
the cause of which has been the subject of much controversy, is
stated now to have almost disappeared. Hofer’s hypothesis that
the Bacteriwm which he named Bact. pestis astaci must be held
responsible has not been borne out by tests undertaken by both the
German Ministry of Health and the Hygienic Institute, while his
opinion that the organism in question acquired its first virulence in
factory waste waters in Belgium is also controverted by the present
author. It is stated that attempts to demonstrate the action of an
ultra-microscopie virus failed.

The author is of opinion that the original focus of infection was
at Gambara, in Italy, whence the disease spread through western
and north-western France, northern Germany and Russia to Siberia.
Another path can be traced along the Danube depression to the
Black Sea. The dissemination of the disease appears to have taken
place within a period of forty years, and indications—stated to have
been neglected by other investigators—pointed to the pathogenicity
of a species of the Saprolegniaceae which the author found in 1902,
and named Aphanomyces magnusi. This fungus is said to be
absent in healthy animals, and to be able to produce the typical
symptoms of the disease on inoculation. The failure of other
workers to recognize its causal relations to the disease is considered
to be due to the extraordinary complexity of the symptoms which
it can produce. American Cambaridae are stated to be immune.

GREENBAUM (S. S.). On the biologic properties of pathogenic
molds.—-Journ. Infect. Diseases, xxxi, pp. 26-81, 1922.

The work recorded in the present paper was undertaken with the
following objects: a study of the proteolytic and amylolytic fer-
ments of 26 pathogenic fungi; their action on various sugars and
on litmus; a study of indol production; and a study of the toxins
of several species.

The results of experiments conducted under uniform conditions
to ascertain the comparative proteolytic properties of the fungi in
10 cc. of 10 per cent. gelatine showed that complete liquefaction
was obtained in 24 hours with two species of Trichophyton [which
are named], with Microsporon pubescens, and Achorion quincke-
anum ; moderate liquefaction in the same period with three species
of Trichophyton and Sporotrichum beurmanni; and slight liquefac-
tion with eight species of Trichophyton and Microsporon lanoswn.
No liquefaction was obtained with Trichophyton rosacewm, Micro-
sporon audouint, M. fulvum, Sporotrichum gougeroti, Actinomyces
bovis, Achorion schoenleinii, and A. gallinae. The ring-worm fungi
in this group, however, caused liquefaction at a later stage.

i a

|

411

- Both Truffi and Roberts showed that liquefied gelatine was able
to hold and transmit the proteolytic body, but this was not always
true for the organisms in the present study. In several cases when
the filtered liquefied gelatine was placed in contact with fresh
gelatine no liquefaction of the latter was caused. When the lique-
fied gelatine possessed a definite enzymic power, this was found to
vary in activity according to the organism which had produced it.
Whereas in some cases the fresh gelatine was liquefied in 24 hours
with a given quantity of the liquefied material, others required 48
hours to complete the process. The variation in the activity of the
gelatinase with the organism was due less to the rapidity with
which the latter grew than to the quantity or quality, or both, of
the gelatinase,

The author was unable to detect sugar with Benedict’s solution
at any time during the two months of the growth of the fungi in
a starch-water medium. They grew well in 3 and 5 per cent.
starch solutions, indicating their capacity to assimilate the larger
starch molecule without previous hydrolytic changes.

For the study of sugar fermentation and litmus reaction a
Russell’s modified double sugar medium prepared with lactose and
glucose was used, together with a series of tubes each prepared
with one only of the following: lactose, glucose, maltose, saccharose,
dextrine, or levulose. The fungi grew well on these media, but
lacked the characteristics given by Sabouraud’s concentrated and
proof media. None of 15 species of Trichophyton, 4 of Microsporon,
and 4 of Achorion tested altered litmus or caused fermentations of
any of the sugars. The same organisms grown on identical media
without peptone also failed to ferment any of the sugars used.

Bohme’s technique (Journ. Amer. Med. Assoc., 1xxvii, p. 959, 1921)
was used for indol production, the organisms being planted in sheep
serum broth. Indol could not be detected in any of the implants,
some of which, however, failed to grow.

Toxin production was studied in Trichophyton acuminatw,
T. gypseum asteroides, Microsporon audouini, Sporotrichum bewr=
mani, and Achorion schoenleinii, cultivated in a proof medium
with bouillon as a base and sealed to prevent evaporation. The
Trichophyton spp. and Sporotrichum were grown for eight weeks,
the others for fourteen, and the cultures were then filtered through
sterile filter paper and a sterile Kitasato candle. A control flask of
the medium was filtered in the same way. Intraperitoneal injec-
tions into eight guinea-pigs with 4 cc. of each medium proved fatal
with the Trichophyton spp. and Achorion, but gave negative results
with the others. Death supervened in 24 hours after injection, with
T. acuminatum, in 10 days with T. gypsewm asteroides, and in 12
days with Achorion schoenleinii. A post-mortem examination
revealed a marked suprarenal vascular disturbance resembling that
produced by the intraperitoneal injection of diphtheria toxin.
Cultures made from the peritoneal fluid remained sterile.

Departmental Activities: The Schools of Agriculture and Experi-
ment Stations.—Jowrn. Dept. Agric. S. Africa, vi, 3, p. 205,
1923.

Grasshoppers of several species in the vicinity of Cedara were

412

decimated in December 1922 and January 1923 by a severe epi-
zootic of a fungous disease caused by Hmpusa gryllt Fresenius. The
diseased individuals exhibited the characteristic habit of crawling
to the top of the grass to die. This circumstance facilitates the
dissemination of the conidia, which are produced in abundance on
the surface of the insect a few hours after death and thrown off on
to the surrounding foliage, thus infecting other grasshoppers. In
some areas nearly every blade of grass bore a victim. Prolonged
periods of low evaporation being necessary for the best development
of the fungus, its scarcity in the preceding season may be explained
by the drier weather in December 1921 [see also this Review, i, p. 391].
Weather conditions were also responsible for the relatively mild
attack of Entomophthora megasperma Cohn on the two worst
South African species of cut-worm in 1922, as compared with its
virulence in the preceding year, the early rainfall of 1921,in the wet
season, when cut-worms are most numerous, being absent in 1922.

Le Mout (L.). La destruction des insectes nuisibles par les
parasites végétaux. [The destruction of injurious insects by
vegetable parasites. |—Rev. de Bot. appliquée, ii, 18, pp. 84—
102, 1923.

The author gives an account of his earlier work in connexion
with the formation in various parts of France of syndicates for the
destruction of cockchafers [see this Review, i, p. 355]. The work
was accomplished by the ordinary methods known at that period
(1889), namely, the capture of the insects when stupefied by dew
and the collecting of larvae after ploughing.

Altogether, over 5,000,000 kg. of cockchafers were destroyed
during the seven years over which the work extended. It was
obvious, however, that such primitive methods had serious draw-
backs. They could not, for instance, be employed in seasons when
ploughing was delayed, since the insects burrow into the soil at the
first sign of cold weather; they were also useless in fields bearing
perennial crops, such as lucerne.

In 1890 the author became acquainted with the work of the
Russian professor, Krassilstschik, a pupil of Metchnikoff, who, in.
1884, had constructed a small experimental factory at Smela (Kiev)
for the artificial production of the fungus Metarrhizium anisopliae,
parasitic on Cleonus punctiventris, a serious pest of sugar beets.
In four months 55 kg. of pure spores of the fungus were produced
on maize beerwort at a temperature of 25°[C.], 1 sq. m. of the
liquid yielding 189 to 200 gm. of spores at each collection, which
took place fortnightly. By this method sufficient spores were
obtained to cause epidemics which destroyed from 55 to 80 per cent.
of the insects in small areas in 10 to 15 days.

In 1890, on an estate in the Orne Department, the author found
numerous mummified larvae of cockchafers, some of which were
covered with a pink growth of Beawveria densa (Isaria densa
Giard). In 1891 and 1892 he used cultures of this fungus on in-
fested soil with great success; one field was estimated to contain
over 20,000 mummified larvae after treatment. The cultures take
some time to produce the necessary effects (from the autumn to the
spring in certain cases), but their influence is of long duration. The,

413

fields treated in 1890 are still exempt from the insects. The average
quantity of spores required per hect. is 5 kg., which is mixed with
Lhectol. of soil and scattered broadcast immediately before ploughing.
The rest of the work is accomplished by natural means. In
meadows and plantations it is necessary to raise the grass or dig
holes for the insertion of the cultures.

The author is convinced that Jsaria furinosa (the conidial stage
of Cordyceps militaris) can be substituted for Spicaria verticilloides,
which is considered by some to be only a variety of the former [and
is sometimes known as Spicaria farinosa var. verticilloides], in the
control of the Cochylis and Hudemis of the vine. Beawveria globu-
lifera (Sporotrichum globuliferum), which is employed in the
United States against Blissus leucopterus, is probably adapted also
to the control of the vine Phylloxera.

From Holland cultures have been received of Cladosporium
aphidis which will probably be efficacious in the control of plant
lice, and will be tested against Phyllowera. Schizoneura lanigera
and other insects with subterranean colonies can in all probability
be controlled by inoculation of the soil with B. globulifera, which,
in 1916, completely destroyed these insect pests on the author’s
apple trees. This method is more permanent than merely spraying
the trunk and branches with a suspension of the spores. In 1892
larvae of what appeared to be EHlater segetis infested by B. globu-
lifera were received from Nantes. In general the author believes
that all soil-dwelling pests are likely to yield to treatment with
a suitable fungus. His laboratory now contains cultures of thirteen
entomogenous fungi, further experiments with which on various
insects are in progress.

The cultures for field use are made chiefly on potato and carrot,
and should be broken up and mixed with sand or mould before
spreading on the soil prior to ploughing in. Care must be taken
to keep free from contamination the cultures used for inoculating
the flasks in which the fungus is multiplied on a large scale; im-
purities in the latter, unless such as are obviously visible, are of
less importance, since no further cultures are made from them. The
essential point is to use really large quantities of the fungus, small
doses being too uncertain in their effects, and this can only be done
by adequate organization.

Nakapba (N.) & Takimoro (K.). Bacterial blight of Hibiscus.—
Ann. Phytopath. Soc. Japan, i, 5, pp. 13-19, 1 fig. 1923. [In
Japanese, with English summary. |

An undescribed bacterial leaf spot of Hibiscus has been under
observation in Korea since 1913. The disease, which affects the
cotyledons of young plants when two to three leaves are expanded,
first appears in the form of minute, circular, black spots which
gradually increase in size, the margins finally becoming angular.

The edges of the spots assume a whitish-yellow tinge or water-

soaked appearance, and when the leaves are severely attacked the

whole plant becomes blackened and withered. The causal organism

(Bacterium hibisci n. sp.) has been isolated and its pathogenicity

proved by inoculation experiments. It is a cylindrical rod with

rounded ends, occurring singly, in pairs, or concatenate, 1-2 to 2 by

Es

eer ee ea ee

414

0-6 to 0-7 », motile by means of one or two polar flagella, forming
no spores Gram negative, staining readily in carbol fuchsin, aniline
water, gentian violet, and aqueous methylene blue: surface colonies
on agar smooth and circular, slightly elevated in the centre and
finely granular under magnification, shiny and cement-coloured by
reflected light; bouillon culture clouded after 20 hours at 25° to
27° C.; gelatine slightly liquefied, milk slowly peptonized, no gas
produced, nitrate slightly reduced, no reaction of indol, thermal
death point 42° C., aerobic.

The results of an experiment in seed disinfection carried out in
April 1921 showed that the plants grown from seed treated with
mercuric chloride 1 in 1,000 or hot water (55° C.) for ten minutes
remained healthy, while those in the untreated control plots de-
veloped 50 per cent. of disease. The organism is thus proved to be
capable of overwintering on the seed. The application of a 55-50
spray of Bordeaux mixture was found greatly to reduce the
incidence of infection.

TELLEZ (O.). Una plaga en el estado de Jalisco: La ‘ pinta’ o
‘clavo’ de la naranja y de la guayaba. [A pest in the State
of Jalisco: The ‘spot’ or ‘knob’ disease of the Orange and
the Guava. |—Rev. Agric. (Mexico), vi, 11, pp. 651-682, 2 figs.,
1922.

This disease, caused by Glocosporiwm psidii, is very common in
the State of Jalisco, Mexico. The brown, coriaceous, circular spots,
from 1 to 4 mm. in diameter, form crusts on the rind of the fruits
and penetrate to a depth of 7 or 8 mm. In the case of the guava,
they are so numerous that they may cover the whole of the skin,
but they are more scattered on the orange.

In the control of the disease the following measures are stated to
give good results:—Spraying with Bordeaux mixture (2:76 kg—
2-76 kg.—200 litres) every fortnight, beginning just before the fall
of the petals and ending when the fruits are nearly ripe. All fallen
leaves must be burnt and the ground under the trees kept clean.
Each tree requires from 4 to 5 litres of the spray mixture, one man
being able to treat 100 trees per day. After picking it is well to
wash the fruits in a 9 per cent. solution of vinegar, and then
they must be rinsed in fresh water and placed to dry on reed mats.

Hopkins (E. F.). The Sphaerulina leaf-spot of Clover.—Piyto-
path., xiii, 3, pp. 117-126, 2 pl., 3 figs., 1923.

A disease of white clover (Trifolium repens), new to America,
was observed by the author at Missouri in 1920 and subsequently
identified as Sphaerulina trifolii E. Rostr. The loss caused by
it is probably not great, although it may cause some defoliation.

The first symptom is the appearance of minute, black lesions on
the leaves, petioles, and stipules. Later these spots enlarge and
have a light brown to grey centre, surrounded by a dark reddish-
brown margin; they bear perithecia, especially under moist
conditions, the infected tissue becoming water-soaked.

The morphology of the fungus is described, the ascospore
measurements being 30-4 to 39-5 by 12.2 to 15-ly.

Numerous isolations of the fungus were made. On potato agar

415

the colonies were white at first and then gradually became black,
except for a white border. The black structures failed to show
any asci or pycnospores. When growing actively the cultures have
a pleasant fruit-like odour.

Inoculation experiments with pure cultures were not very
successful, but in one case strong infection was obtained on
mammoth clover (7. pratense perenne), medium infection on white
clover, and slight infection on red clover (7. pratense). Re-isolations
were successfully made. By suspending leaves bearing perithecia
over healthy plants under a bell jar, infections were obtained
without difficulty. A table is given showing the relative sus-
ceptibility of eight different clovers, of which mammoth clover
appears to be the most susceptible.

The first case of infection in 1922 was observed on 17th March
after heavy rain. The germ-tubes from the ascospores penetrate
the epidermis directly, sometimes after growing some distance.
No appressoria were observed, but the empty walls of the ascospore
persist for some time after infection has taken place.

BonANNI (A.). La tubercolosi o rogna dell’ Olivo. [Tuberculosis
or scab of the Olive tree.|—Le Staz. Sper. Agr. Ital., lvi, 1-3,
pp. 124-144, 2 pl., 1922.

In this paper the results are given of a detailed study of the
olive knot disease caused by Bacteriwm savastanoi E. F. Smith,
with which the author has frequently found various other bacteria
as well as budding and filamentous fungi, all of which are regarded
as incidental invaders of the tumours. Inoculation experiments
were carried out which prove the pathogenicity of Bact. savastanot
and the inability of the other organisms mentioned to cause
infection. The morphological and cultural characters of the
pathogen are described. It was found to have peritrichous flagella
instead of the one to four polar flagella described by E. F. Smith,
but the author does not attach much importance to this dis-
crepancy, which he thinks may be due to the staining technique
employed.

In agreement with Schiff-Georgini, the author distinguishes
between the primary tubercles resulting directly from the entrance
of the causative agent through lesions, and the secondary tubercles
produced by metastasis in which vessels are the path through
which the infection is transmitted, while the tegumentary tissues
remain perfectly sound. The first type occurs always on young
twigs, where the younger tissues favour bacterial development. In
this case the bacterial cavity is situated in the cortical tissues
and there is a hyperplasy of the bark. From the cortex the
infection spreads to the central cylinder and through the woody
layers to the pith. On reaching the vessels more extensive
diffusion of the organism commences and the second form, the
metastatic tubercle, is produced. In this type infection starts from
the vessels and proceeds tangentially and radially from the in-
fection centre. The bacterial cavities are found only in the wood
and the ceil prolification causes the rupture of the cambium and
bark layers as the tubercle increases in size.

The conditions which predispose to the disease are stated to be

416

sometimes connected with the soil, sometimes climatic, and some-
times to depend on the constitution of the plant. Insects may
be carriers of the organism and wounds allow infection to take
place.

Mryake (C.). On a brown shot hole disease of Cherry leaves
caused by Mycosphaerella cerasella Aderh.— Ann. Phytopath.
Soc. Japan, i, 5, pp. 31-42, 1 pl., 1923. [In Japanese, with
English summary. |
Investigations on Mycosphaerella cerasella Aderh., which causes
the brown shot-hole disease of the cherry (Prunus cerasus) and
also of P. yamasakura var. typica, P. yamasakura var. spontanea
subvar. hortensis, P. itokasura, and P. itokaswra var. swbhirtella, in
the west of Japan, were carried out at the Ohara Institute, Okayama.
The genetic relation between Cercosporella cerasella Sace. and the
Mycosphaerella was demonstrated by comparative cultural studies
of the isolations secured from both the ascigerous and conidial
stages, the morphology of which are described in Japanese and
illustrated by excellent figures. The parasitic nature of M. cerasella
was determined by successful inoculations carried out on the above
mentioned varieties of cherry.

Mier (H. C.), Moz (E.), & MULuer (K.). Einige Ergebnisse
unserer Beizversuche 1921-22. [Some results of our dis-
infection experiments 1921-22. |—Deutsche landw. Presse, |, 6,
pp. 48-49, 3 figs., 1923.

The authors have carried out extensive experiments with the
following preparations, the value of which they consider may now
be regarded as definitely established.

Against bunt of wheat caused by Tilletia [tritici] formaldehyde
(40 per cent., immersion for 15 minutes in a 1 in 400 solution) gave,
on the whole, very good control, but its injurious effects on germina-
tionand subsequent vigour of the plants wereundeniable. Thetreated
plants also sutfered considerably from frost. Germisan (immersion
in 0-25 per cent. for 15 or 30 minutes; or sprinkling, 0-5 and 0-75
per cent., 15 litres of solution per 100 kg. of wheat, covered for 8
hours) gave very good protection. The stand was normal and some
of the plots considerably above the average. Weizenfusariol
(applied according to directions) controlled the disease very well
both with immersion and sprinkling. In the latter method the
seed should be washed before sprinkling to ensure good results.
Uspulun (0-5 per cent. immersion for one hour) was very satis-
factory, but the 0-25 per cent. solution proved inadequate. The
results of sprinkling were conflicting, but in one case, when the
seed had been previously washed, they were very good. The
growth of the plants was excellent. Kalimat, the active principle
of which is an unstable compound of phenol and formaldehyde, has
all the advantages of the latter without. its drawbacks. Good
results were obtained both by immersion (0-25 per cent. for 30
minutes) and sprinkling (0-33 per cent.)

Against the stripe disease of barley due to Helminthosporium
[graminewm ], germisan (immersion in 0-25 per cent. for one hour
or sprinkling with 15 litres of the solution at a strength of 0-75

417

per cent., 8 hours covered) gave the best results. In some cases it
was necessary to immerse in a 0-5 per cent. solution and even then
the disease was not absolutely controlled. The growth of the treated
plants was extremely satisfactory. Uspulun (0-5 per cent.,
immersion for two hours) also gave good results, but failed to
control the disease entirely.

Against the snow Fusarium [F. nivale] of rye, germisan (0-25
per cent., immersion for one hour) gave almost complete control of
the disease, the number of ears in the treated plants being nearly
double that of the untreated. Sprinkling at the same strength also
gave good results. Roggenfusariol (used according to directions)
was equal to germisan. Uspulun (immersion for one hour in 0-25
per cent.) gave satisfactory results. In the sprinkling method
(50 gm. per 15 litres of water) the effect was slightly weaker but
still adequate. 778 (immersion for 15 minutes in 0-75 per cent.)
gave very satisfactory control.

Against the flag smut of rye due to Uvrocystis [occulta], the
results obtained have already been published [see this Review, ii,
p- 170]. In addition to the preparations therein mentioned, 778
(0-5 per cent. immersion for 15 minutes) gave very good control.

Against the loose smut of oats, caused by Ustilago [avenae],
formaldehyde (40 per cent., immersion for 15 minutes in 1 in 400
solution, or sprinkling with 201. of 1 in 200 solution per 100 kg.
of oat seed, covered for 2 hours) gave excellent control of the
disease. In most cases the stand of the crop was satisfactory.
Germisan (immersion for 30 minutes in 0-25 per cent. solution or
sprinkling with 30 1. of 0-75 per cent. solution per 100 kg. of oat
seed) gave excellent control and vigorous growth. Sublimoform
(used according to directions) effectively controlled the disease, but
somewhat impaired germination and energy. Kalimat (immersion
for one hour in 0-25 per cent. or sprinkling with 20 litres of 0-3
per cent. solution per 100 kg. of seed) gave absolute control of the
disease and improved the appearance of the stand.

It is pointed out that, owing to the depreciation of the German
currency, the cost of germisan and other mercurial preparations
will soon become prohibitive, while kalimat, being manufactured
from home-produced raw materials, is readily obtainable at a
reasonable price. It is a first class fungicide, especially for the
control of bunt of wheat, loose smut of oats, and flag smut of rye,
and causes no injury to germination.

Morstatr (H.). Bibliographie der Pflanzenschutzliteratur: das
Jahr 1922. [Bibliography of plant protection literature
published in ny rd ae gl re Reichsanst. Land.- und Forst-
wirtsch., Berlin-Dahlem, 162 pp., 1923.

This comprehensive bibliography of the literature published
during 1922 relating to the various aspects of plant protection is
divided into the following four sections, each of which is further
sub-divided into appropriate groups: general; diseases and causes ;
host plants; plant protection measures (comprising legislation,
administration, statistical information, and preventive and curative
methods).

418

Rao (K. A.). A preliminary account of symbiotic nitrogen fixa-
tion in non-leguminous plants, with special reference to
Chomelia asiatica.— Agric. Journ. India, xviii, 2, pp. 132-
143, 2 figs., 1923.

The author in this preliminary paper adds another plant, Chome-
lia asvatica, to the list of species which bear nitrogen-fixing bac-
teria in nodules on their leaves. Von Faber (Jahrb. Wiss. Bot., 51,
p. 285, and 54, p. 243) investigated the symbiotic relationships of
the bacteria in the leaf nodules of five species of Rubiaceae, and
showed that they had the remarkable property of fixing nitrogen
from the air. Miehe (Ber. d. Bot. Ges. 34, p. 576), working on the
Myosinaceae, came to similar conclusions.

Chomelia asiatica, a Rubiaceous shrub, bears ten to twelve
generally round and rarely irregular bacterial nodules on each leaf,
situated at the junction of the veins with the midrib. Pavetta
indica—previously described by von Faber—was studied for pur-.
poses of comparison. Stomata serve as points of entry, from which
the bacteria pass into the intercellular spaces, and penetrate there-
from between the cells, causing the latter to divide vigorously. A
special nodule tissue is thus formed, with the result that the leaf
swells on the affected side. In older stages liquefaction of the
nodule tissue was noticed, possibly owing to digestion of the
bacteria by the host.

The organism was isolated by inoculating nitrogen-free mannite
solution [see Ashby, Journ. Agric. Science, ii, p. 38] with an emul-
sion of teased nodules. The liquid medium recommended by von
Faber was also used. After subculturing five times on the liquid
medium the organism was plated on the gum arabic agar medium
of von Faber. The colonies develop slowly on this solid medium,
and are extremely small, milky white, opalescent, thin, round, and
of a gummy consistency. The bacteria stain well with ordinary
stains. They prefer an alkaline reaction and plenty of air. Their
nitrogen-fixing capacity was tested from cultures in Ashby’s
medium.

The bacteria are most active at growing points in the leaf
primordia of unopened buds, but they can be found between the em-
bryo and the endosperm of the seed, and apparently also in the
vegetative apex of the embryo. Successful cultures were obtained
from seeds, leaf buds, and ovaries. During germination the bacteria
can be found in the growing points. The infection is thus evidently
hereditary. Pot culture experiments are in progress to ascertain
whether the bacteria are necessary for plants of Chomelia asiatica
to thrive, as is said to be the ease with Pavetta indica.

The nitrogen content of the leaves of these plants must be large,
and the author suggests their application in large quantities as a
manure, a practice which appears to be in vogue already among the
Tamil cultivators of Ceylon.

WEIMER (J. L.) & Harter (L. L.). Pectinase in the spores of
Rhizopus.— Amer. Journ. of Bot., x, 4, pp. 167-169, 1923.

The results of experiments with the ungerminated spores of

Rhizopus tritici and R. nigricans showed that both species con-

tain an enzyme, pectinase, which is capable of dissolving the middle’

419

lamellae of sweet potatoes. The rate of action of the enzyme was
tested by immersing raw sweet potato disks in a suspension of
spores treated so as to prevent germination. That of the spores of
KR. tritici was comparatively rapid, the raw sweet potato disks
being completely macerated in twenty-four to forty-eight hours.
R. nigricans, on the other hand, acted very slowly, taking seventy-
two hours or longer to accomplish maceration. This is in harmony
with the authors’ previous results regarding the activity of the
enzymes of these two fungi [see this Review, 1, p. 273].

It is probable that pectinase plays an important part in the early
nutrition of the fungus, while it may also be a factor in the initial
infection of some of its hosts.

Harter (L. L.) & Wetuer (J. L.). Amylase in the spores of
Rhizopus tritici and Rhizopus nigricans.— Amer. Journ. of
Bot., x, 2, pp. 89-92, 1923.

The results of experiments in the growth of Rhizopus tritici and
R. nigricans at various temperatures showed that the former pro-
duced spores in profusion at 20° to 38° C., and the latter at 16° to
30°C. Amylase was found to be contained in the spores at any
temperature at which they were produced. The same held good
with respect to the mycelium, which, as Harter has already shown
(Journ. Agric. Res. xx, p. 781, 1921), produced amylase when
grown at temperatures ranging from 9° to 40° C., the enzyme being
most active when the fungus was grown at 9°, and least at 40°. The
available data are not sufficient to justify the conclusion that the
amount of amylase contained in the spores is correlated in any way
with the temperature at which the organism was grown.

Comparative tests of the hydrolysing power of the spores and
mycelium grown at the same temperature have shown that the
enzyme of the latter is more active than that of the former when
compared on the basis of unit weight.

Matsumoto (T.). Further studies on physiology of Rhizoctonia
solani Kuhn.—Bu/l. [inp. Coll. Agric. and Forestry (Morioka,
Japan), v, 63 pp., 1 pl., 8 figs., 1923.

The results of inoculation experiments with various strains of
Rhizoctonia solani on the leaves of Azuki and broad beans, Cameria,
sliced potato disks, and cucumber stems have shown that mechanical
pressure exerted by the hyphae is an important factor in the
penetration of the cuticular layer and cell wall. The latter process,
however, appears to be assisted also by the action of enzymes or
allied substances liberated by the invading hyphae.

The effect of H-ion concentration varies according to the nature
of the media used, and it is, therefore, almost impossible to name
a definite optimum P,, value for the growth of the fungus. In no
case was mycelial growth secured on any medium having a P,, value
of 2-5. As regards the limit of alkalinity the results of the tests
were less consistent. Thus on Czapek’s solution mycelial growth
was fairly luxuriant at P,, 9-8, while in turnip or potato decoction
it was scanty even at P,, 8-5. The change of the P,, value due to
the growth of the fungus in the culture media is not constant but
appears to fluctuate with the different solutions used.

420

Further experiments were conducted to ascertain the effect of the
H-ion concentrations on the activity of the enzymes secreted by
the fungus. The amylase of the strain PI (isolated from an infected
potato stem in California, 1917) is active within a range of P, 3-4
to 9-4, the optimum being about 6-2 or less. A marked acceleration
of invertase activity occurs on the acid side, the optimum after
twelve hours being observed at the exponent P,, 2-8, and after two
days at P,, 3-2. On the alkaline side invertase activity is markedly
retarded, the limit appearing to be P, 9-1. The optimum H-ion
concentrations for maltase and emulsin seem to be approximately
P,, 6-0 and P,, 5-2 respectively. Gelatine is liquefied by the mycelial
extraction when NaOH is added, but not when HCl is used.
Liquefaction, however, may take place in the latter case also if
the enzymes secreted by the living hyphae are substituted for the
mycelial extractions.

When grown on potato the fungus secretes intracellular and
extracellular pectinase by means of which it dissolves the middle
lamellae of the host plant tissue. The diastatic activity, both
intra- and extracellular, of the various strains of Rhizoctonia
studied, increases in proportion to the mycelial growth, the maxi-
mum activity occurring immediately before sclerotial formation.
Diastase and invertase are always found in appreciable quantities
when the fungus is grown on any of the media studied, the amounts
not necessarily being increased when the carbohydrate supplied was
starch or sucrose respectively. The fungus secretes maltase in any
medium, but the enzyme is produced in large quantities when
maltose is present. Maltase is more active in the extracellular than
in the intracellular enzymes.

Glycerine can be utilized to a great extent in the presence of
peptone, but not in that of ammonium nitrate or sodium nitrate.
Rhizoctonia thrives on carbohydrate media containing peptone as a
source of nitrogen, the rate of its development being proportionate
to the amount of peptone used, at least up to 4 per cent.

In glucose media containing 0-1 per cent. NH,NO, the hyphal
growth increases in proportion to the degree of the concentra-
tion of glucose, provided that the latter does not exceed 3M.
[.W. = 1 molecular weight in grammes in 1 litre of water], while in
solutions containing 0-2 per cent. NH,NO, the best growth is
ebserved on media with a higher concentration of glucose up to
3M. In general, sclerotial formation was more or less checked
as the concentration of glucose increased within the limits tested.
The hyphal growth of the fungus appears to be somewhat retarded
by the addition of even low concentrations of tannin, though a very
low concentration stimulated mycelial growth on sucrose-containing
media. Tannic acid inhibits the diastatic action of the fungus even
at the lowest concentration used. At 0-083 per cent. no hydrolysis
of starch was observed. Tannic acid does not appear, however, to
affect the action of invertase.

‘Staling’ phenomena were observed in the cultures of this fungus.
The deleterious action of the toxic substances in staled solutions was
more marked in some of the author’s experiments when the cultures
contained the filtrate of the media formerly occupied by a different
strain of the fungus. These toxic substances may be deactivated by

421

heating, and the growth of the fungus is promoted by eliminating
them even if no more nutrient is added.

The fusion of hyphae occurs more readily between those of strains
isolated from the same species of host than between isolations from
different hosts.

In general it can be said that the physiological characteristics of
Rhizoctonia solani may be more or less modified by environmental
conditions, and may also vary with the different hosts on which it
occurs.

GARNER (W. W.), McMurtrey (J. E.), Bacon (C. W.), & Moss (E. G.).
Sand drown, a chlorosis of Tobacco due to magnesium defi-
ciency, and the relation of sulphates and chlorides of potas-
sium to the disease.— Journ. Agric. Res., xxii, 1, pp. 27-40,
7 pi. (1 col.), 1923. -

The principal results of the authors’ investigations on sand drown
of tobacco have already been noticed [see this Review, ii, p.80]. In
the présent paper the experimental work on which the conclusions
already reported are based is described in considerable detail,
especially with regard to the methods of pot cultvre, which involve
certain important modifications of those ordinarily used in the study
of fertilizer problems.

Gram (E.). On Kartoffelbrok og Foranstaltninger mod denne i
vore Nabolande. | Wart disease of Potatoes and the legislation
against it in force in neighbouring countries. |—Ugeskrift for
Landmaend, \xviul, 3, pp. 32-33, 1923.

Considering the position with regard to wart disease of potatoes
(Chrysophlyctis endobiotica) [Synchytrium endobioticwm] in coun-
tries adjacent to Denmark, the author thinks that the Danish
quarantine legislation [see this Review, i, p. 125] was promulgated
only just in time. Should the disease once gain a foothold in
Denmark, the quarantine regulations of other countries would very
considerably reduce the Danish potato exports.

In Germany the disease is greatly on the increase, especially in
industrial districts. In the Rhine Provinces there are at least 200
hect. of infected ground, and in Westphalia 250 hect. The disease
occurs also in various parts of Saxony, Silesia, Hanover, and
Brandenburg. From the Danish point of view, however, the
greatest importance attaches to the spread of the disease in Meck-
lenburg, Hamburg, Liibeck, and Schleswig-Holstein, whence it may
very easily be introduced into Denmark by means of small frontier
transactions, or by fishermen landing at the ports.

In Holland there are 75 hect. of infected ground, all in the
possession of smallholders and the peasantry. Since 1920 the
cultivation of resistant varieties on infected soil has been permitted,
subject to annual inspection. Potatoes may be imported from Great
Britain when accompanied by a certificate of freedom from wart
disease, but not from Germany.

In Norway, where the disease is very prevalent in the vicinity
of Christianssand, the cultivation of the resistant British varieties,
King George, Great Scot, Lochar, and Templar, has been proceeding
on a large scale since 1920,

422

The disease has not been observed in Sweden since 1913, when
the only case of infection was promptly suppressed by means of
crop rotation and soil disinfection with 1 per cent. formalin. It is
possible that the subsequent absence of infection may also be due
to the inability of the fungus to withstand the severe northern

winters.

Criaus (E.), Kécx (G.), & JANCHEN (E.). Neuere Erfahrungen iiber
den Einfluss von Uspulun und Uspulunbolus auf die Kartof-
felertrage. [Recent experiments on the influence of uspulun
and uspulunbolus on Potato production. |—Oesterr. Zeitschr. fiir
Kartoffelbau, ii, 8, pp. 29-380, 1923.

The results of previous experiments (Oesterr. Zeitschr. fiir Kartof-
felbau, i, 11, pp. 41-42, 1921) showed that the yield from potatoes
treated with uspulunbolus before planting considerably exceeded
that of the untreated controls. A further series of tests carried out
in 1922 both with uspulun and uspulunbolus gave conflicting results,
the yield in certain plots being higher, and in others lower, than in
the untreated controls. On the whole, the favourable effects pre-
dominated, the average increase in the yield being estimated at 25
to 45 per cent. Uspulunbolus not only acts as a stimulant to pro-
duction but also as a preventive of decay in storage. Further in-
vestigations are necessary to determine the correct degree of
maturity of the potato at the time of treatment and the meteoro-
logical conditions in which the best results may be expected.

Zum Auftreten des Kartoffelkrebses in Béhmen. [The occurrence
of wart disease of Potatoes in Bohemia. |— Wiener landwirtsch.
Zeit., xxiii, 1-2, p. 3, 1923.

Wart disease of potatoes [Synchytrium endobioticum], which in
1921 was reported from only one locality in the north of Czecho-
Slovakia, has been steadily spreading to other districts, and the
situation is now regarded as very serious. According to a member
of the National Agricultural Council, the entire potato cultivation
of Czecho-Slovakia is imperilled unless absolutely immune varieties
can be secured for planting. The export of potatoes from the in-
fested districts has been prohibited.

PARAVICINI (E.). Die Kartoffelkrankheiten in Niederlandisch-
Ost-Indien. [Potato diseases in the Dutch East Indies. ]—
Centralbl. fiir Bakt., Ab. 2, lviti, 9-12, pp. 212-220, 1923.

Mosaic disease is responsible for very severe damage to the Dutch
East Indian potato crops, especially in Western Java and the
Tengger mountains, where the amount of infection at a recent in-
spection was estimated in certain fields at 75 per cent. The average
yield per plant was only 65 gm. as compared with 151 gm. from
healthy plants.

Leaf roll also causes considerable losses in the Tengger moun-
tains and the Preanger Regency. It does not occur in Central
Java or Sumatra.

Early blight (Alternaria solani) attacks not only potatoes but
various other Solanaceae, e.g. tomato, eggplant, Solanwm wendlan-
dii, Cyphomandra betacea, and Datura sp.

Late blight (Phytophthora infestans) and bacterial ring disease

4.23

(Bacillus solanacearum) are of minor importance in the Dutch
East Indies. Blackleg [Bacillus atrosepticus| and Rhizoctonia
diseases occur only in isolated cases, and the attacks are negligible
in severity and extent. Various species of Fusuriwm, Verticillium,
and a species of Rosellinia frequently destroy the roots of potatoes
grown on freshly reclaimed forest land.

Sprain (‘ Rostfleckenkrankheit ’) is a tuber disease which cannot
be detected externally. Sections of affected tubers, however,
reveal irregular, brown spots, very variable in size, number, and
position. The spots are never situated in the region of the vascular
bundles, nor do they extend to the surface of the tubers. The
brown discoloration is due to cork layers surrounding single cells or
groups of cells. The starch content undergoes no change, but there
are other indications of abnormal chemical processes. Sprain does
not occur on tubers under 20 gm. in weight, and sometimes affects -
only a few tubers on a plant.

Attempts to isolate a causal organism from affected tubers gave
negative results, and the disease is believed to be due to chemical
disturbances consequent on a deficiency of lime in the soil. Ex-
periments in the control of the disease by liming the soil gave con-
tlicting results. The cultivation of infected potatoes on compara-
tively healthy soils, however, gave a sound crop in the third
generation.

Sprain neither reduces the yield of the crop nor spoils the
flavour of the potatoes. Their appearance, however, is much im-
paired, and they fetch a lower price than healthy ones. The
expensive white varieties are more severely attacked than the
ordinary yellow ones cultivated in the Dutch East Indies. Certain
‘indigenous’ varieties, e.g. Kentang Djawa, Colonjo, and Radja
Singa, are almost immune from sprain. The last-named variety is
quite free from sprain in Central Java, but on being transferred to
the Karo Plateau, where the disease is very severe, 2-4 per cent. of
the tubers became infected. Besides the Karo Plateau, where
potato cultivation has been almost brought to a standstill owing to
the ravages of sprain, the disease is also very severe in the Tengger
mountains and Poetjon (Eastern Java). In the Preanger Regency
it has been declining in severity for some years. It occurs more
extensively in comparatively low-lying situations than at high
altitudes, : ‘

Actinonvyces scab (A. scabies) is of widespread occurrence, and is
steadily increasing on the yellow varieties. Its economic impor-
tance, however, like that of the dry rot caused by different species
of Fusarium, is negligible in the Dutch East Indies.

Lasiodiplodia | Diplodia] tubericola has been found on potatoes
exported from Java to America, and the mycelium of Phytophthoru
erythroseptica on potatoes which had rotted in transit from Java to
Holland. Neither fungus has previously been known to occur in
Java.

Bispy (G. R.). Manitoba Potato diseases and their control.—
Manitoba Farmers’ Library Extension Bull. 66, 19 pp., 10 figs.,
1923.

A brief account in popular language is given of the causes,

424

symptoms, and effects of the principal fungous and physiological
diseases of potatoes in Manitoba, together with appropriate
measures for their control. Leaf roll and mosaic are stated to be
the most serious diseases occurring at present in the province. Dry
stem rot and black scurf (Rhizoctonia solani), blackleg (Bacillus
atrosepticus), wilt (Fusarium oxysporum), and dry rot (F’. discolor
sulphureum and other species of Fusariwm) also cause severe
losses. Late blight (Phytophthora infestans), powdery scab
(Spongospora subterranea), and wart disease (Synchytriwm endo-
bioticum) are not known to occur in Manitoba.

There is at present no potato variety on the market which is
resistant to the above diseases occurring in Manitoba, but growers
are advised to cultivate exclusively healthy seed of the following
standard varieties: Early Ohio, Beauty of Hebron, Irish Cobbler,
and Green Mountain.

FRANCHINI (G.). Essais d’inoculation de latex parasitisé aux
souris blanches. Abcés du foie expérimentaux déterminés
par les amibes des latex. [Inoculation experiments with
parasitized latex on white mice. Abscesses of the liver pro-
duced experimentally by latex amoebae.]—Bull. Soc. Path.
exot., Xvi, 3, pp. 162-166, 1 fig., 1923.

It was shown in a previous paper [see this Review, ii, 5, p. 229]
that the inoculation of white mice with the parasitized latex of
various species of Huphorbia resulted in slight infection. The
present paper describes in detail the technique and results of a
further series of experiments on nine white mice. In two cases
(one of peritoneal inoculation and the other of ingestion of a culture
from the spleen of a mouse inoculated with latex from £. anti-
quorum), a post-mortem examination revealed hypertrophy and
abscess of the liver. In both cases amoebae were found in abun-
dance, especially near the edges of the abscess and in the digestive
tract, and phagocytosis of the red corpuscles took place on a large
seale. Cultures of the amoebae on Noller’s medium resulted in the
production of the forms previously described.

In the seven remaining mice of the series the effects of inocula-
tion with, or ingestion of, the latex of various species of Huphorbia
and Urtica were less pronounced, while a post-mortem examination
of six others similarly treated gave negative results.

FRANCHINI (G.). Action du latex d’Euphorbes sur différents try-
panosomes. Culture de flagellés dans des latex divers. [The
action of the latex of Huphorbiae on various trypanosomes. ]|—
Bull. Soe. Path. exot., xvi, 1, pp. 41-50, 1923.

Experiments are described in some detail which show that
various species of Trypanosoma (T. lewisi, T. gambiense, T. brucei,
&e.), as well as the organism of oriental sore [Leishmania tropica]
and some species of Herpetomonas from animals, can live for a
considerable time in latex, and in some cases multiplied freely in
latex cultures.

425

SHARPLES (A.) & LAMBOURNE (L.). Preliminary report on brown
bast experiments in Malaya.—WMalayan Agric. Journ., Xi, 2,
pp. 30-35, 1923.

The results of the first series of field experiments on the produc-
tion of brown bast in Malaya indicated that the systems of tapping
rubber trees in common use were not sufficiently drastic for the
purposes of comparative tests, a single daily cut on a quarter or half
the tree not producing enough brown bast to lead to any definite
conclusions. Experiments with spiral cuts were accordingly under-
taken. After seven months the incidence of brown bast in the
plots tapped on the full spiral system every third day was only
5 per cent. as compared with 10 per cent. in the plots tapped on
alternate days, and 20 per cent. in those tapped daily. An extension
of the interval between successive tappings is therefore clearly
shown to be advisable [see this Review, 11, pp. 232 and 396].

The total yield from trees tapped on a half spiral every third
day during seven months was higher than would be expected on a
proportional basis when compared with the yields from those
tapped daily or every other day. This point is of considerable im-
portance in relation to the brown bast problem, many investigators
being agreed that the disease is a wound response due to over-
tapping. The results of these experiments indicate the possibility
of yields being limited by the development of a high percentage of
brown bast. In the writer’s opinion the yield is sharply limited
according to the type of soil and general growth conditions. Below
this limit the amount of brown bast developed is of little practical
importance, but above it there is so great an increase in the disease
as to counteract the augmented yield. This point must be con-
sidered in the general question of obtaining high-yielding strains of
Hevea brasiliensis by bud-grafting and selection.

It was found during the course of the experiments that in order
to obtain a guiding line as to the behaviour of different plots with
reference to brown bast development, at least three months previous
heavy tapping was necessary. A second series of experiments con-
firmed the previous observation of a sudden rise in the incidence of
brown bast during certain months, followed by a long period of
quiescence. In 1919, and again in 1921, March to August was a
quiescent period; in 1922, however, May, June, and July were
heavy brown bast months. Hence there is some difficulty in corre-
lating the incidence of brown bast with meteorological conditions or
other external factors. Another interesting feature in this series of
experiments was the cessation of the extension of brown bast at
definite points marked by the different ages of the tapped bark.
Out of 410 trees tapped in virgin bark above the 36 inch level, 133
developed the disease. In 40 of these no extension took place after
tapping was stopped; in another 20 the brown bast was checked at
the 36 inches mark, which indicated the junction between the
virgin and the youngest renewed bark of previous cuts; in 47 trees
the brown bast extended to the 24 inches mark, which indicated
the junction between the old and young renewed bark, and in 19
the affection extended to the base of the tree.

In one plot of 44 trees tapped on a seven-eighths spiral the
response to tapping was obviously abnormal. From November

426

1920 to August 1921 only two cases of brown bast were reported,
followed in September 1921 by a sudden increase of six diseased
trees. From that time until December 1922 the plot developed the
normal heavy incidence of the disease found on severely tapped
trees, and this was correlated with a sudden increase in the average
tree yield. The conclusion must be drawn that brown bast is
closely associated with high yields, and that it will act as a limiting
factor in high production.

In numerous cases the appearance of the brown bast symptoms is
so sudden that it may be classed with the phenomena dependent on
‘trigger action’, i.e.,a sudden release followed by immediate effects.
The typical symptoms of brown bast frequently appear in twenty-
four hours on trees which seemed perfectly normal the day before.
It appears highly probable that brown bast is due to a process of
exhaustion.

The recently described breaking-down of the sieve-tubes which
has been regarded as an incipient stage of brown bast [see this
Review, i, p. 144], and included under the term phloem-necrosis, is
characterized in other cases of phloem-necrosis by lignification of
the cellulose walls of the sieve-tubes. The latter phenomenon,
however, frequently accompanies tapping, even in trees which
cannot be suspected of brown bast. Pending further inquiry, there-
fore, the relation of this condition to the disease cannot be regarded
as established.

Attention is drawn to the risks attendant on the system of bud-
grafting from high-yielding trees which is now widely practised in
Malaya. High yielders are known to succumb to exhaustion
earlier than trees with an average production, and one of the results
of bud-grafting already observed is an insufficient development of
leaf cuticle, which facilitates attack by various species of fungi,
which are normally saprophytic. At present there is a very
dangerous alga, Cephalewros mycoidea, epiphytic on rubber leaves,
which causes serious damage to tea, cloves, and pepper [see this
Review, ii, p. 337], and would certainly injure Hevea if it succeeded
in penetrating the thin cuticle of the bud-grafts. The authors think
that the bud-grafting results are not sufficiently encouraging to

form the basis of a definite policy, especially in view of the great.

risks attaching to the system.

SHARPLES (A.). Final report on treatment of mouldy rot disease
with agrisol.— Malayan Agric. Journ., xi, 2, pp. 36-37, 1923.
For eighteen months the rubber trees on an estate infested by
mouldy rot (Sphaeronema fimbriatum) have been treated with
agrisol [see this Review, i, p. 329]. While total eradication of the
disease appears to be impossible, very effective control has been
secured at the remarkably low cost of 10% cents [about threepence]
per acre per month, ‘The macrospores of S. fumbriatum, unlike the
spores of the Phytophthora of black stripe canker, are resistant to
desiccation, and a recurrence of the attack under suitable conditions
is therefore probable after dry weather has caused its temporary dis-
appearance. The number of affected individuals, however, may be
reduced to a minimum by the routine application of agrisol on the
lines previously recommended.

ied

427

EDWARDES (J.). Mould prevention tests with sodium silico-
fluoride.— Bull. Rubber Growers’ Assoc., v, 1, pp. 21-24, 1923.

The promising results previously obtained by Dr. Stevens in the
prevention of mould on sheet rubber with sodium silico-fluoride
have already been described [see this Review, i, p. 263, and ii,
p. 139]. Further tests showed that the solution was etfective as a
fungicide at a concentration of 0-25 per cent., the minimum quan-
tity necessary for coagulation being 1-5 gm. to 3,000 cc. standard
latex. Two series of samples were therefore tested to determine the
effect of soaking sheet rubber in solutions of the chemical of different
strengths: (a) S.S. F. sheet soaked for two hours after smoking
in sodium silico-fluoride solution; and (+) S.S. F. sheet soaked for
thirty minutes before smoking in sodium silico-fluoride solution.
The advantage of soaking the sheet before smoking was most
marked, producing resistance to mould under very favourable con-
ditions for twenty-two days in the case of the saturated solution.
The rubber treated with the higher percentage solutions did not
absorb moisture as readily as the controls which quickly developed
an opaque strip in the interior, causing the effect usually termed by
the brokers ‘ undercured ’.

Further tests in which both acetic acid sheet and sheet coagulated
with sodium silico-fluoride were exposed to heavy rains for periods
of two hours and an entire night respectively, showed that resistance
to mould was greatly increased by the use of sodium silico-fluoride.
The extreme liability of acetic acid sheet to mould was strikingly
illustrated in these tests,

Mizusawa (Y.). A bacterial rot disease of Saffrons.—Ann.
Phytopath. Soc. Japan, i, 5, pp. 1-12, 1923.

Bacterial rot of the saffron crocus [Crocus sativus] was first
observed in Japan in 1909, but attracted no special attention till
1917, since when its severity and distribution have considerably
increased.

The first symptoms of the disease become noticeable in December,
when the leaves lose vigour, wither, and gradually turn yellow.
The roots and corms are found to be dark brown. This is the
common form of the disease which results from successive culture
in infected fields. Im the rare cases when diseased corms are
planted in healthy fields infection occurs at some point of the
sheath, followed immediately by yellowing of the leaves.

The causal organism, a peritrichiate bacterium, to which the
name JSacillus croci n.sp. is given, was repeatedly isolated from
decayed corms and sheaths. It resembles, but is not identical
with, Bacillus carotovorus, B. ommivorus, B. oleraceae, and B.
avroideae. It is a medium sized rod, with rounded ends, 1-2 to 3-2
by 0-6 to 1-ly, usually single but occasionally in pairs or short
chains. Endospores and capsules not seen. Flagella two to four.
Gram negative. It grows readily on various media, especially with
the addition of sugar, producing white, round colonies, On carbo-
hydrate media the organism produces acid but no gas. The opti-
mum temperature for development is 25° to 28°C., the maximum
40° C., the minimum below 10°C., and the thermal death point
55°C. The results of experiments showed that the organism can

428

tolerate a high degree of acidity. It retains its virulence for a
period of ten to twelve months. The morphological and physio-
logical characters are fully described. Healthy corms inoculated
with pure cultures of the organism rapidly exhibited the typical
symptoms of the disease. Bacillus croci remains on the decayed
part of the plant and in the infected soil. The disease is dissemin-
ated mainly by transplanting infected corms. The group number is
221.2233082.

The selection of healthy corms and disinfection of seed corms in
saturated lime water for half an hour are recommended.

Disease defeated by drainage.—South African Sugar Journ., vii,
2, p- 179, 1923.

Prof. Cobb, entomologist to the Cairns (Queensland) Sugar
Bureau, in the course of a report on gummosis (Bacillus vascularwm)
of the H. Q. 426 variety of sugar-cane, states that the chief factors
responsible for the disease are: (1) poor drainage; (2) an imper-
vious subsoil within two or three feet from the surface ; (3) defective
cultural methods; and (4) abundant rainfall. Rotation of crops is
recommended on land which has long been under susceptible
varieties of cane.

An example of the benefit derived from proper drainage was
brought to Prof. Cobb’s notice at Halifax [Queensland], where a
sixty-acre plantation on the river bank is intersected by a road.
On the side adjoiming the river good crops of sugar-cane have
always been obtained, while the cane grown on the other portion,
which is bounded on the far side by 2 swamp, has invariably been
a failure. By cutting a few deep main drains through the block
emptying on to the swampy land, and running cross drains into
them, the present owner has succeeded in raising a fine crop
of cane.

Crayton (E. E.). The relation of temperature to = Fusarium
wilt of the Tomato.— Amer. Journ. of Bot., x, 2, pp. 71-87,
4 pl. 1 fig., 1923.

There are three different tomato diseases in the United States,
supposed to be caused by three distinct species of Fusarium. They
are the ‘summer blight’ of California, the ‘yellow blight’ of the
Pacific North-west, and ‘ Fuswrium wilt’, the last-named being one
of the most serious tomato diseases in the southern States. For
this disease, which is due to F. lycopersici, the author has deter-
mined definite {temperature limits under greenhouse conditions in
Wisconsin soil-temperature tanks. The behaviour of the fungus
was tested by incubating pure cultures of a strain of the fungus
from Indiana at each of twelve graduated temperatures ranging
from 4° to 38°C. It was found that the minimum for growth was
9° to 10°C., the optimum about 28°C., and the maximum 37°C.
Under greenhouse conditions the soil temperature range most
favourable to the development of the susceptible commercial tomato
varieties, Mangus and Chalk’s Early Jewel, was 24° to 31°C., a
range which, therefore, includes the optimum temperature for the
development of F. lycopersici. Growth was still vigorous at 33°,

429

but was checked at 35°, while it decreased gradually from 24° to
below 19°C.

The symptoms of the disease vary in relation to the soil tempera-
ture in which the host plant is grown. There is an optimum soil
temperature for the disease between 25° and 31°C., characterized
by a sudden wilting, usually without yellowing, first of the lower
leaves and then of those higher up. At temperatures immediately
above or below the optimum, namely 33° C., or 20° to 24° C., wilting
is accompanied, and often preceded, by yellowing of the leaves.
The appearance of the plants suggests a slow blight rather than
wilt, and they are often stunted. At temperatures above 34° or below

~20° C. there is no external evidence of the disease. Under certain
temperature conditions the fungus may penetrate only into the
bundles in the lower portion of the stem; this is often the result of
a brief exposure to temperatures favouring the disease, followed by
a fall in temperature sufficient to check the further development of
the fungus.

It is reasonable to expect that changes in temperature would not
equally increase or decrease both the attacking power of the fungus
and the resistance of the host. The correlation between the tem-
perature ranges of the host, the parasite,and the disease, considered
separately, is closer in this case than usual in similar diseases. It
is especially marked at the optimum points, which are approxi-
mately equal for both host and fungus, as well as for the disease
caused by the interaction of the two. On the other hand, the
disease develops more rapidly at 31° than at 25°, though the fungus
grows at least equally well at the latter as at the former tempera-
ture. So also the growth of the fungus at 33° to 34° C., the upper
limit for the disease, was much less vigorous than at 19° to 21°C.,
the lowest temperature at which the disease occurs. Both host and
parasite can develop at a wider range of temperature than the
disease, the latter being absent above 34° or below 20°, though both
are within the growth range of the tomato and of the Fusarium.

In two of the experiments both air and soil temperatures were
controlled. The air in three greenhouse compartments was main-
tained at temperatures of 17°, 27°, and 33°C. respectively. Three
different soil temperatures were maintained in each of these com-
partments, namely, 17°, 27°, and 35°C. Air temperature was
found to be as effective as that of the soil in controlling the appear-
ance of the disease, which developed fatally in only two of the nine
combinations of air and soil temperatures, namely, warm air (27° C.)
and warm soil (27° C.), and hot air (33° C.) and warm soil (27° C.).
At a cool air temperature (17°C.) and optimum soil temperature
for the disease (27° C.), heavy infection occurred in the root and
extended up into the basal portion of the stem, but there were no
external symptoms of the disease. The temperature conditions of
soil and air most favourable to the disease are 27°C. and 28°C.
respectively, with short interludes of sudden rises in air temperature
to 33° or 34°C,

The evidence accumulated during the course of these experiments
indicates that the wilting and death of plants attacked by F. lyco-
persici is due to toxic action rather than to a mechanical plugging
of the xylem bundles.

430

TayLor (W. H.). Tomato diseases. Black-stripe and its control.
—New Zealand Journ. of Agric., xxvi, 2, pp. 101-103, 1923.

A serious outbreak of blackstripe disease of tomatoes (? Bacillus
lathyri) was recently investigated in the Hutt Valley, Wellington, New
Zealand. A comparison of the diseased plots with adjacent healthy
fields indicated that the epidemic was promoted by the application of
excessive quantities of stable manure, and that the injurious effects
of the latter can be counteracted by an additional dressing of
blood-and-bone and sulphate of potash, this being attributed to the
action of potash, which stiffens the tissues of the plant and also
improves the quality of the fruit. The results of recent experiments
in Canada are stated to show that the disease can not only be pre-
vented, but actually cured by fertilizing the plants with acid phos-
phate or bone-flour (3 oz. per plant) and potassium sulphate (4 oz.
per plant) either before transplanting or just as the blooms appear ;
while in England watering with sulphate of potash solution or
dressing with the sotid compound is reported to enable the infected
plants to grow away clean when attacked by B. lathyrv.

Dr Konine (M.). Een nieuw bestrijdingsmiddel tegen de wortel-
zwam. [A new measure for the control of the root fungus. |—
Tijdschr. over Plantenziekten, xxix, 1, pp. 1-4, 1923.

All attempts to eradicate the ‘ root fungus’ (Trametes radiciperda)
| Fomes annosus]| from Dutch pinewoods have failed, including the
method of separating the diseased from the healthy trees by means
of trenches.

In September 1922, the Dutch Heathland Association made an
excursion to Bremen, where a system of so-called ‘forest rejuvena-
tion ’, which the author thinks would be of service in Holland in
connexion with this disease, was seen. As soon as the trees show
signs of deterioration, felling is carried out on a large scale, all the
less valuable timber being cut down to provide light and air for
new seedlings. Then the ‘humus layer’ of moss and needles is
removed as far as the soil in strips about 2 m. broad, and placed on
the intervening strips, which are about 1 m. broad. The bare
patches are then sown with a mixture of beech, silver fir, larch,
birch, oak, Sorbus, and Prunus. This procedure serves the double
purpose of providing a*good humus layer and of keeping the root
fungus in check, the latter rarely occurring in mixed plantations.

RicHarpson (A. D.). Witches’ Broom on Silver Fir.—Gard. Chron.,
lexis p11, 2 fis. 192s;

‘ Witches’ brooms’, the popular name for the globose swellings
caused by Peridermiwm elatinwm, are very common on silver firs
(Abies pectinata) in Ireland and the western parts of Great Britain,
where these trees are more extensively grown than in the east of
the country. The stems of affected trees are considerably weakened,
and liable to break under wind pressure, and the value of the
timber is much depreciated.

The first symptom of infection is a small swelling, which keeps
pace with the growth of the affected branch or stem. Erect shoots
are often produced from such swellings, giving the characteristic
‘broom’ appearance. The leaves arising from affected shoots are

431

short, pale, and of annual duration only, defoliation occurring in
the autumn. The aecidia are produced on the under side of the
leaves. The bark is ruptured and cast off at the cankered
swellings. .

P. elatinum is the aecidial stage of the heteroecious fungus
Melampsorella caryophyllacearum, the uredo and teleuto stages
being produced on the stems and leaves of Stellaria, Arenaria,
Cerastiwm, and other Caryophyllaceae.

The disease is prevalent on the Continent, and has also been
found on Abies nordmanniana, A. cephalonica, A. pinsapo, A.
balsamea, and A, sibirica.

VALCKENIER-SURINGAR (J.). Eine Ulmenkrankheit in Holland.
[An Elm disease in Holland. ]— Mitt. deutsch. dendrol. Gesellsch.,
XXX, pp. 145-147, 1 fig., 1922.

After a brief recapitulation of the symptoms of the obscure
disease of elms occurring in Holland and the north of France [see
this Review, i, pp. 277, 334, and ii, pp. 1, 92], the author questions
the accuracy of the conclusions reached by Miss Schwarz as to the
identity of the causal agent. The fact that the Graphium isolated
from diseased elms produced a brown discoloration (but not the
other typical symptoms of infection) when inoculated into healthy
trees is not a convincing proof of pathogenicity. Several fungi are
known to produce similar discolorations on elms and other trees,
and in the absence of further proof of its causal relationship to the
disease the author is unable to accept Miss Schwarz’s conclusions.
He also regards her description of the fungus as a new species
of Graphium uli as requiring further confirmation.

Durrinoy (J.). Biologie de l’Armillaria mellea. [Biology of
Armillaria mellea.|\—Bull. Soc. de Path, Vég. de France, ix, 4,
pp- 277-281, 2 figs., 1922.

In the Pyrenees, and particularly above Bareges, Armillaria
mellea is responsible for the destruction of the birch, and in the
Landes region it is, in common with Trametes pini, and to some
extent Rhizina undulata, amongst the principal cryptogamic
enemies of Pinus maritima. On the outskirts of the latter region,
cork oaks whose roots are attacked by Heterodera radicicola are
reported to be killed by the same fungus. Other workers have
recorded it seriously injuring fruit trees in Lot-et-Garonne and
elsewhere. Although possibly able to attack vigorous trees, the
fungus appears to act usually as a secondary parasite under circum-
stances which are still not clearly defined. Chestnuts suffering
from ink disease may be attacked by A. mellea, while young chest-
nuts planted too deeply are very liable to be killed by this form of
root rot, as the mycelium first attacks the asphyxiated roots, then
the underground region of the collar, and may finally ascend in the
cambium of the trunk to a distance of several metres above soil
level.

The extended use of resistant varieties, which may be employed
as stocks in certain cases as, for instance, in growing walnuts, is
recommended.

432

GREENWOOD (F. W.). Collar-rot in Pea crops on the Wairau plain.
—New Zealand Journ. of Agric., xxvi, 1, pp. 35-37, 1 fig.,
1923.

Serious damage to pea crops in the Wairau Plain, Marlborough,
New Zealand, is reported. The disease, which is caused by a species
of Fusariwm, first appears in the stem just above the collar, subse-
quently spreading to the roots, which are reduced to a putrid mass.
Extension upward along the stem also occurs. Infection is carried
on the seed and straw, rarely through the soil.

The worst attacks occurred on badly drained and sour soils, and
also on very sandy soils in which nitrogen was deficient. The
application of lime is recommended.

NEWHALL (A. G.). Seed transmission of Lettuce mosaic.—Piyto-
path., xiii, 2, pp. 104-106, 1923.

Lettuce mosaic is usually present to the extent of 3 to 6 per cent.
in western New York, but was very prevalent in 1921, its spread
being correlated with a general infestation of aphids. Milkweed
(Asclepias syriaca) and water dock (Rumex britannica) were tried
as overwintering hosts, but inoculations were negative. In order
to test the possibility of seed transmission, seed was harvested from
twelve diseased plants and sown. The seed from three of these plants
yielded twenty-seven mosaic seedlings out of 563 grown, whilst that
from the remaining nine, grown in sterilized soil under very
carefully controlled conditions, gave fifty-one mosaic plants out of
1,465. These results were supported by field observations, and
both seem to prove that mosaic of lettuce is frequently transmitted
through the seed.

GLEISBERG (W.). Plasmodiophora brassicae Woron.: Zur Auswer-
tung von Kruziferen-Infektionsreihen. {(Plasmodiophora
brassicae Woron: On the evaluation of infection tests with
Cruciferae.|—Nachrichtenbl. deutsch. Pflanzenschutzdienst, iii,
2, pp- 10-12, 1922.

In order to test the susceptibility of a number of Cruciferae to
club-root (Plasmodiophora brassicae), ninety-three plants belonging
to the sub-families Siliquosae, Siliculosae, and Nucamentaceae were
sown in heavily infested plots in 1922. Only fifty-two of the
species germinated, among which the incidence of infection is given
in detail. There was complete absence, or barely a trace, of infec-
tion in the Arabideae (except Cheiranthus allionii, 20 per cent.),
several of the Sisymbriae, Alysseae, Lepidieae, Brassica napus and
B. rapa; 70 to 100 per cent. of infection in B. cernua, B. juncea,
Sinapis alba, and various Alysseae, Camelineae, and Thlapseae.
The remainder were intermediate. An adjacent plot of white cab-
bage showed 100 per cent. of infection, while the wild form of B.
oleracea had only 16-6 per cent. The immunity of B. rapa and
B. napus conflicts with Sorauer’s statement that all cultivated
forms belonging to these two species are susceptible to the disease.

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

APPLIED MYCOLOGY

Vou. II OCTOBER 1923

BEACH (W.S8.). A crown rot of Rhubarb caused by Phytophthora
cactorum.— Pennsylvania Agric. Exper. Stat. Bull. 174, 28 pp.,
5 pl., 1922.

In a short introduction the author states that the Phyto-
phthora crown rot of rhubarb in Pennsylvania, to which he called
attention in a previous report [see this Review, i, p. 102] is caused
by Phytophthora cactorwm (Leb. & Cohn) Schroet., heretofore
known in America mainly as causing a disease of ginseng and
a rot of apples and pears. As some experimental results indicate
that the fungus from ginseng or apple may pass over to rhubarb,
the crown rot of the latter will probably be found to have as wide
a range of distribution as the other two diseases. Near Philadelphia,
where rhubarb is fairly extensively grown, a number of fields have
had to be abandoned owing to the disease. The heaviest losses
usually occur in new plantings, the general practice of dividing old
crowns for setting new hills apparently facilitating the entry of
the parasite through the wound surfaces, the principal source of
infection appearing to be the diseased plants in the original field.
In a typical case cited by the author, a field was set in the spring
with setts taken from a place where there was a mild degree of
infection. By the end of September only 46-1 per cent. of the hills
had healthy and vigorous plants, while 34-2 per cent. had been
completely destroyed; 9 per cent. were still alive but showed
typical symptoms of attack, and 10-7 per cent. were weakly and
probably diseased. Plants attacked late in the season may recover
sufficiently to become more or less productive the next year, but it
is probable that they are the leading source of future infection.
In older fields the plants are killed comparatively slowly; those
that survive the setting-out season in a vigorous condition appear
better able to withstand further attacks.

The first outward symptom of the disease, which usually appears
during July, is the wilting of one or of a few leaf blades, followed

K

434

by a loss of turgidity in the leaf stalk, so that the whole leaf
structure falls prone on the soil. In warm, muggy weather the
symptoms, which may appear in leaves of any age, are rapid in
development and spread to other leaves, the whole plant being
killed in a few days. In some cases, however, only a section of the
crown is killed, the rest of the plant appearing healthy until
another rainy period revives the activity of the fungus. In plants
in an advanced stage of wilt, an extensive brownish-black discolora-
tion marks the area occupied by the mycelium, while brown,
depressed lesions develop on the surface of the portions of the leaf
stalks enveloped in the crown. All the rotted tissues contain the
mycelium, at first intercellular but later penetrating the cells. The
fungus usually does not advance far into the petioles; a prolonged
rainy period occasionally renders possible the infection of young
leaf blades or the upper parts of the petioles, but ordinarily the
aerial parts wilt and collapse as a consequence of the destruction of
the crown and roots. The tissues invaded by the Phytophthora are
at first not much softer in texture than healthy ones, but secondary
saprophytes soon bring about the complete disintegration of the
affected parts.

It seems probable that a sufficiently prolonged drought may
preclude the development of the crown rot in any season, yet the
disease has been evident to some degree in the vicinity of Phila-
delphia each year from 1918 to 1921; the damage was greatest in
1920 and least in 1918, the former summer being very wet and the
latter very dry during the critical time for the development
of the disease. No dithculty was met in securing infection in
April both on roots and petioles of rhubarb in frames. It is
probable that the fungus becomes established much earlier than
indicated by the first outward symptoms. According to field
observations, the disease is able to assume severe proportions on
well drained soil, although heavier losses occur on low, wet areas.
The physical character of the soil seems to have no influence, except
as it tends to increase the water-holding capacity. A rich, fertile
soil appears, however, to increase the resistance of the host to the
fungus.

Inoculation experiments with Phytophthora cactorwm from
rhubarb gave positive and usually fatal results in practically all
instances in which the cultures were inserted in wounds. A small
proportion of inoculations without wounding succeeded, but only
under very favourable conditions of temperature and moisture.
Infection failed in an experiment in which macerated cultures were
worked into the soil around the roots of twenty seedlings in pots,
care being taken not to wound the roots. Taking into consideration
the apparent relation of wounding to the severity of crown rot in
the field, it would appear that the fungus is but little able to infect
through perfectly sound roots; but though both observations in
nature and the general results of the infection experiments indicate
that wounding is a very important factor in the spread of the
disease, some experiments have shown that infection can take place
through the uninjured epidermis under favourable conditions. In
culture the maximum temperature for growth was 33°C., the
optimum near 25° C., and growth was still possible from 7° to 9° C.

CG ep TRE Pe BSE Or ee

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435

Oospore production was heavier below 20°C. than above, the

‘reverse being the case as regards conidia.

It seems probable that, as in the case of the ginseng disease, the
conidia are distributed by wind and by rain. There are also
indications that oospores lying in decaying tissues are carried
along the rows by cultivation. The writer records cases where the
disease was introduced into new fields through oospores and possibly
latent mycelium present in the roots.

Oospores were only twice found by the author upon rhubarb
material, but were freely produced in culture. Cenidia are
always produced during damp weather on the petiole lesions
above the soil. Comparative tables of measurements of the spores
from different hosts are given in support of the conclusion that the
fungus described is Phytophthora cactorum. This morphological
agreement is confirmed by the fact that the form from apple is
capable of infecting rhubarb and causes crown rot, although it is
somewhat less virulent than the rhubarb isolations. P. fagi, as
known in Europe, is thought to be at least biologically distinct.

For the control of the disease, the planting of setts from infected
stock should be avoided, and new plantings with stock started from
seed under disease-free conditions or from a healthy field should be
made on soil on which rhubarb has not been grown for a con-
siderable number of years. The destruction of infected plants early
in the season and the disinfection of dormant roots before planting
are strongly recommended. Bordeaux mixture sprayed into the
crowns and over the petioles promises to be effective in preventing
the spread of the disease in summer, but will not prevent the decay
of plants already attacked.

Mention is made of two other Phytophthora diseases of rhubarb
in the United States, the outward symptoms of which are similar
to those described above. One of these, caused by P. parasitica
var. rhei, is being described by Godfrey under the name ‘foot rot’
[see following abstract]. In this case, besides morphological
differences from P. cactorum, the causal fungus appears to be
adapted to higher temperatures, but although the disease caused by
it progresses somewhat more rapidly during hot weather, there
appears to be little difference in the ultimate damage done by the
two parasites. The other, also a serious foot rot, occurs in southern
Mlinois, and is recorded in this paper for the first time. It is
caused by a third species of Phytophthora, the identity of which
has not yet been established.

Goprrey (G. H.). A Phytophthora foot rot of Rhubarb.—Journ.
Agric. Res., xxiii, 1, 26 pp., 12 pl. 3 figs., 1923.

The present paper is the first record of*a serious foot and root rot
of rhubarb caused by Phytophthora parasitica var. rhei. It has
been found in Maryland, the District of Columbia and Virginia,
but is probably much more widely distributed. In outward
symptoms, final damage done, and weather relations, the disease
closely resembles the crown rot in Pennsylvania described by
Beach [see above abstract].

The fungus was isolated and grown on various culture media, the
morphological and cultural characters being briefly described. It

436

readily infects rhubarb plants, with or without wounding, causing
the typical symptoms of the disease and usually killing the plants.

Inoculations on other hosts showed that the fungus was able to rot
apples, and readily attacked parsnips and carrots, causing a soft wet
rot which, in the latter case, spread to the growing leaves. Turnips
were slowly decayed without softening, and in sweet potatoes the
rot caused was also firm and dry. On ordinary potatoes the
symptoms resembled those caused by P. erythroseptica. Green and
ripe tomatoes were rapidly attacked, but inoculations on young
tomato plants failed. Colocasia was immune, and onion practically
so. On Ricinus communis the young inflorescences and leaves
were successfully infected, but the attack was confined to small
spots and did not spread.

There is a full discussion of the taxonomy of the fungus, which
is regarded as being morphologically similar to P. parasitica,
except in the size of the oospores, which average about 25 yw in the
rhubarb fungus as against 18-6 u in P. parasitica. Other differences
from this species are the divergent results obtained on inoculating
various other hosts such as tomatoes, and some variations in ability
to grow on certain media. These differences are not regarded at
present as of more than varietal significance, and the new variety
rhei of P. parasitica Dastur is proposed. P. melongenae Sawada
and P, terrestris Sherb. are also regarded as belonging to the same
series and not as distinct species. A detailed English diagnosis of
the variety rei is given.

Preliminary experiments indicate that spraying with Bordeaux
mixture, during the usually brief period when infection is likely to
occur, gives promise of successful control. The other measures
recommended are essentially the same as for the disease caused by
P. cactorum described above.

Howitt (J. E.). Two diseases new to Ontario.—Scient. Agric.,
ii, 5, p. 189, 1923.

During the summer of 1922 the author's attention was drawn to
two diseases, apparently new to Ontario, of considerable economic
importance, namely pink root of onions, caused by Fusariwm malli
[see this Review, i, p. 405], and white rot of grapes due to
Coniothyrium diplodiella [see this Review, ui, p. 45].

Diseased onions from a marsh bordering on Pelee Point were
found to be attacked by F. malli, which is prevalent in the onion-
growing marshes south-east of Leamington, Ontario. In 1922 at
least fifty acres were affected. Outside the Bermuda onion-growing
regions of Southern Texas, the economic importance of this disease
has not yet been generally recognized, and it requires immediate
attention. ,

White rot of grapes was first observed by the writer in a
vineyard near Winona, Ontario. Observations in the Niagara
district in 1922 indicated that the disease may cause serious damage
to certain commercial varieties, especially Agawam (Roggers No.
15). Over 80 per cent. of the bunches in unsprayed rows of this
variety were unmarketable. The disease, which must not be con-
fused with the somewhat similar black rot caused by Guignardia
bidwellii, may be controlled by spraying with Bordeaux mixture.

437

Moreau (L.) & VINET (E.). Contribution a l’étude de l’apoplexie
de la Vigne et de son traitement. [Contribution to the study
of apoplexy of the Vine and its treatment.|—Comptes Rendus
Acad. Agric. de France, ix, 1, pp. 32-36, 1923.

For the last three years the authors have set asidé for the
investigation of apoplexy 1-5 hect. of their experimental vineyard
containing 6,750 vines at Belle-Beille [ Angers, Maine-et-Loire]. It
was found that the disease, hitherto believed to be peculiar to the
south, was equally virulent in the west of France. In 1920 the
number of vines killed per 1,000 was 35, in 1921, 10, and in 1922, 65.
Examination of dead vines in the vineyard showed that in 1920,
90 per cent. and in 1922, 80 per cent. were attacked by the parasite
responsible for the ‘esca’ disease [Fomes igniarius: see this
Review, i, p. 416].

The development of the disease is very gradual, the final phase
often setting in quite unexpectedly when the internal damage
reaches a point at which the tissues are no longer able to convey
enough water to meet losses through transpiration. Sometimes,
however, a progressive withering of the leaves and tendrils may
indicate the approaching death of a branch. In some casés partially
defoliated branches form new shoots in July or August, the
reduction of evaporation consequent on the loss of leaves being
sufficient to preserve the vitality of the buds and enable them to
sprout.

The symptoms of the disease may be traced from year to year in
a gradual chlorosis, in the failure of the wood to mature properly,
and in the withering of individual branches. An examination of
the interior of the diseased vines almost always reveals the presence
of the tinder-like decay characteristic of the ‘esca’ disease. Death
most often occurs towards the end of the season, the majority of
the fatal cases observed being between 15th September and 26th
October.

Experiments in the control of the disease by the application to
the vines, a few days after pruning, of a solution of arsenite of soda
containing 1,350 gm. of arsenious acid per hectol. of water gave
excellent results, the number of branches affected during the
following season being greatly reduced. By the 26th October the
treated plots had an average of 4 dead and 3 partially dead plants,
while the controls had 65 dead and 71 partially dead.

The tests will be continued to ascertain whether it is sufficient to
treat the vines two consecutive years out of every four, the practice
followed in the south.

Brereton (W. LEG.) & HamBiin (C, O.). Black spot of the Vine
(Gloeosporium ampelophagum): Experiments with controls
1920-21.— Agric. Gaz. New South Wales, xxxiii, 6, pp. 432-
436, 3 figs., 1922.

Experiments were carried out at Hawkesbury Agricultural College
and at Yanco Experiment Farm in New South Wales in treating vine
anthracnose (Glocosporium ampelophagum) to determine the best
winter swabs and sprays, to test summer control sprays, and to test
late season sprays for ripening fruit. The first series was inconclu-
sive, as very little disease appeared during the year, but it was found

4.38

that the application of a swab consisting of 5 lb. sulphate of iron,
one gallon of water, and half a pint of sulphuric acid, delayed the
bursting of the young buds about ten days. At Yanco a similar
delay in the bursting of the buds was caused by the application of
sulphuric acid (1:10) swabs. When applied to vines with the buds
already burst, the swabbing caused the foliage to be burnt off.
Spraying experiments in the winter with Bordeaux mixture
(6-4-22), Burgundy mixture (4-6-22), and lime-sulphur (winter
strength) had no retarding effect. Owing to the late appearance of
the disease, neither swabbing nor winter spraying had any con-
trolling effect.

The following treatment for vine anthracnose is recommended.
(1) After pruning, all cuttings should be collected and burnt. (2) If
time and labour permit, the loose old bark may be removed, and it
must then be burnt. (3) While dormant, the following swabs or
sprays should be applied once or twice : (a) one gallon of water, 5 lb.
sulphate of iron, half a pint of commercial concentrated sulphuric
acid (dissolve the sulphate of iron by suspending it overnight in
a piece of sacking in the water contained in a wooden or earthen-
ware vessel, in the morning add the acid slowly to prevent
spurting); (>) ten gallons of water, one gallon of sulphuric acid.
This is effective both for spraying and swabbing. The. brush
or mop must contain no metal, and the sprayer should be lined with
lead. If the disease has been virulent the preceding season, two
applications are desirable, one five weeks before the bud-bursting
period and another just prior to this event. Where only one
application is decided upon, it should be made as near as possible to
the bursting of the buds, but care must be taken not to leave it too
late, as unexpected sprouting might prevent the work from being
carried out at all. (4) In the spring, when the buds are bursting,
spraying with Bordeaux mixture (6-4-40) must be undertaken,
and another application with the mixture at summer strength
(6-4-50), when the later buds are sprouting. Further spraying
must depend on weather conditions. Spraying during the
blossoming period should be avoided as a rule, but if, through any
cause, the application just before blossoming has been delayed and
weather conditions are favourable to the disease, the sprayings
should be continued rather than risk the spoiling of the entire
crop. The sprayings are also valuable in regard to downy mildew,
which appears later in the season.

Bro.etti (F. T.). Black measles, water berries, and related Vine
troubles.—Califorma Agric. Exper. Stat. Bull. 358, pp. 509-
524, 3 figs., 3 diag., 1923.

There are several obscure diseases of the vine in California,
indiscriminately referred to as black measles, Spanish measles,
black mildew, blight, Anaheim disease, California disease, Santa
Clara disease, and top disease, which appear to be closely allied to
the European ‘brunissure’ and to two other Californian vine
diseases, namely, ‘ water berries’ and ‘ grape shrivel’.

The chief symptoms of the diseases are various spots, patches, and
dead areas on the leaves ; spotting, softening, and premature drying
of the fruit, with absence of sugar, acidity, colour, and flavour ;

eA I i a i Go

439

dying back of the tips of the shoots, uneven or imperfect ripening
of the canes, with a deficiency of starch ; dark spots and streaks in
the wood; short growth and death of arms, branches, or even
entire vines. Various combinations of these symptoms may appear
in individual cases. In black measles, Spanish measles, black
mildew, California, Anaheim, and Santa Clara diseases (which are
distinguishable from one another only by their distribution, the
first three being sporadic and the last three epidemic), any or all of
the symptoms may occur. These diseases appear to represent
a chronic state of the same conditions that produce water berries
and grape shrivel, namely, overbearing and malnutrition.

A study of these diseases of the vine in California affords strong
evidence that the epidemic form of the trouble is due to excessively
heavy crops following good growing conditions and abundant rains,
succeeded by deficient or irregular rainfall. The obvious remedy
for the disease, besides the application of suitable fertilizers and
other cultural measures, is a diminution of the load by short
pruning—down to the base-buds in severe cases. The various types
of the disease merely represent different stages or degrees of the
same trouble. It is very probable that the severity of the final
stages of the disease may be due to some undetected infective
micro-organism or facultative parasite to which the vine is sus-
ceptible only after being weakened by malnutrition.

Swine e (D. B.). How the Department of Botany and Bacterio-
logy has been meeting obligations.—Rept. Montuna Agric.
Exper. Stat. for the year ending 30th June, 1921, pp. 39-44,
3 figs., 1922.

During the period under review an outbreak of fireblight
[Bacillus amylovorus| threatened the destruction of the apple
industry in Montana but satisfactory control was effected. An
investigation of the disease brought to light new facts in connexion
with varietal resistance.

Apple scab [Venturia inaequalis] was reported in Montana for
the first time, and information has been obtained concerning varietal
resistance and rapidity of spread. Lime-sulphur was more satis-
factory than Bordeaux mixture as a protective spray owing to the
serious injury to the fruit caused by the latter.

The results of investigations on brown bark spot of fruit trees,
a destructive disease due to malnutrition, have been separately
published [see this Review ii, p. 221].

A form of plum pockets [Hxoascus pruni], quite different from
the eastern type, destroyed 50 to 90 per cent. of the ordinarily
hardy American plums in the Yellowstone Valley. Satisfactory
control measures, however, were organized. e

Stem rust of wheat [Puccinia graminis] has been considerably
checked by the vigorous campaign of barberry eradication, in which
Montana is one of the leading States. As a result of the serious
epidemic in 1916, when the loss to the wheat crop was estimated
at three million bushels, there has been no lack of co-operation on
the part of the farmers.

A serious wilt disease of sunflowers, caused by a fungus probably
identical with Sclerotinia libertiana, was widely distributed over

440

the State. The first symptoms are usually noticed when the plants
are four to six feet in height, the affected bases of the stems at first
turning black, then brown, and finally yellow. The fungus appears
to spread rapidly through the ground, and diseased crowns and roots
are generally covered with the dense, white mycelium of the fungus,
which afterwards forms large, black sclerotia, especially in the pith.
Young seedlings in the field do not appear to be very susceptibie to
the disease, but the losses among older plants range from 10 to 60
per cent. Inoculation experiments on young sunflower and lettuce
seedlings resulted in the production of the typical symptoms of the
disease.

Osmun (A. V.). The crop disease situation in 1921.—Thirty-fourth
Ann. Rept. Massachusetts Agric. Exper. Stat., pp. 62a-75a,
1922. [Ree’d 1923.]

About the usual number of plant diseases was reported from
Massachusetts during 1921. On the whole the season was free from
serious epidemics, which occurred in three instances only.

An unusually warm and wet spring provided ideal conditions
for the discharge and germination of the spores of the apple scab
fungus (Venturia inaequalis) and resulted in a very severe out-
break of the disease. The McIntosh variety was the most suscep-
tible, showing 90 to 100 per cent. infection in many orchards. A
second period of heavy rainfall in July was accompanied by
considerable secondary scab infection.

Tobaceo wildfire (Bacterium tabacum) was extremely prevalent
in the seed-beds of the Connecticut Valley, probably owing to the
abnormally wet weather during April and May [see this Review, ii,

yaya

t The third disease to occur in epidemic form was the downy

mildew of cucumber and melon caused by Pseudoperonospora

cubensis, which resulted in very severe damage except in places
where it was held in check by the application of Bordeaux mixture.

In no case was the fungicide applied until after the mildew appeared

on the vines, and, judging by the successful results, preventive

sprays can apparently be dispensed with.

The season was remarkable for the almost complete absence of
late blight of potatoes (Phytophthora infestans) which was doubt-
less due to the unusually dry conditions prevailing from August to
October.

A complete list of the 166 diseases diagnosed from over 600 cases
during the year, together with the localities in which they occurred,
is appended.

Annual Report.of the Director Arkansas Agricultural Experiment
Station, 1921-1922, 103 pp., 35 figs. 1922. [Ree’d 1923.]

The following references to subjects of phytopathological interest
occur in the section of the report devoted to plant diseases (pp. 88-
94). Apple scab [Venturia inaequalis], which was particularly
severe during the period under review, was effectively controlled
by spraying. Tomato wilt (Pusariwm lycopersici) is greatly on the
increase, and the frequent occurrence of the disease in crops grown
from seed on virgin soil, led to experiments by Elliott and Crawford

5 eee et eye >

_

44]

which have demonstrated that the fungus is carried on seed from
infected plants [see this Review, ii, p. 92]. Mosaic of sweet
potatoes is widespread, and there has been a serious outbreak of
mosaic on clovers and cowpeas, the latter sometimes being severely
injured and the yield much reduced. On sweet clover [Melilotus]
the disease is perennial and easily spreads from one plant to
another. In the case of the cowpea the disease does not appear to
be carried in the seed, but mosaic was found to be transmitted in
seed from infected horsebeans and bur clover. A serious epidemic
of anthracnose of alfalfa [Colletotrichwm trifolii] occurred in the
Mississippi Valley.

Other important diseases mentioned are cotton blight (Ascochyta
gossypii), cotton wilt [Fusarium vasinfectum], and a bacterial root
rot of maize, but the work on these diseases has already been
noticed in this Review [see ii, pp. 215, 66, and 158 respectively }.

RATCLIFFE (G. T.). The work of the San Antonio Experiment
Farm in 1919 and 1920.—U.S. Dept. of Agric. Circ. 209,
38 pp., 4 figs., 1922. [Ree’d 1923.]

The results of experiments on cotton root rot [Ozoniwm omni-
vorum| extending over the period 1916 to 1919 showed that neither
acid phosphate nor calcium acid sulphate fertilizers controlled the
disease under San Antonio conditions. Mulching was without
effect on the incidence of the disease, and further investigations on
the advantages of aeration in infected fields, indicated that any
benefit derived from the process was of very brief duration.
Root rot was found to occur at a depth of at least four feet.

NeAL (D. C.). Report of the Plant Pathologist.—Ann. Rept.
Mississippi Agric. Exper. Stat. xxxv, pp. 25-28, 1922.
[Ree’d 1923. ]

During 1921 about thirty selections of tomatoes were made at
the Central Station, Mississippi, from the Norton, Marvel, Norduke,
Greater Baltimore, Glove, and Stone varieties, with a view to
developing strains resistant to wilt [Fusariwm lycopersici]. These
selections have been re-propagated in wilt-infected land for observa-
tion during the coming season. The same procedure is being
adopted at the Poplarville Branch Station. So far the yield
records have been somewhat unsatisfactory owing to the drought,
but there is reason to believe that the wilt-resistant strains will
yield better under Mississippi conditions than the ordinary com-
mercial varieties. Attempts at crossing wilt-resistant strains with
early commercial varieties are in progress.

A comparative study of resistance and susceptibility of three
leading sweet potato varieties (Nancy Hall, Triumph, and Porto
Rico) to black rot (Sphaeronema fimbriatum) gave inconsistent
results, probably owing to the drought, and the work will be
repeated. Studies on the surface rot (Pusariwm oxysporum) of
sweet potatoes are also in progress.

Spraying experiments for the control of pecan scab [ Fusicladium
effuswm] are being continued at Ocean’ Springs and Pascagoula
with susceptible varieties, such as Pabst, Success, and Delmas.
The plots are being sprayed with 4-4-50 Bordeaux mixture and

K 2

442

Bordeaux oil-emulsion at intervals of three to four weeks according
to weather conditions.

Forty-first Annual Report Ohio Agricultural Experiment Station
for 1921-22.—Ohio Agric. Exper. Stat. Bull. 362, 59 pp.
1922.

The following references to plant diseases are included in the
report. At Clermont one-tenth and one-twentieth acre plots were
planted alternately with diseased and healthy maize seed in order to
determine (1) the reduction in yield of grain and stover | the stalks
from which the ears have been husked] due to root rot, caused by
Diplodia zeae, which is very prevalent in the west and south-west
of the State, and (2) whether the loss could be eliminated by testing
the germination of the seed before sowing. The seed was carefully
selected in the autumn of 1921, using the modified rag doll method
of germination to determine the relative presence or absence of the
disease. In all plots where diseased seed was used there was a
marked reduction in the yield both of grain and stover. Produc-
tion was also much higher on drained than on undrained land.
The total yield of grain from healthy seed plots on drained land
was 782 1b. and that of stover 5501b., the corresponding figures
for the diseased seed being 486 and 319 lb. respectively. On un-
drained land the total yield from the healthy seed was 321 lb. of
erain and 221 1b. of stover, and from diseased seed 249 1b. of grain
and 150 lb. of stover.

It is evident from the above results that the expert use of the
rag doll germinator greatly increases the maize yield, but the
difficulties connected with the method debar the average grower
from taking full advantage of it.

In southern Ohio apple scab [ Venturia inaequalis] and blotch
| Phyllosticta solitaria| cause a considerable amount of damage, and
spraying experiments on their control were conducted in 1922.
The best results were obtained by the use of lime-sulphur | in 40
applied (1) when the trees were dormant, (2) when the blossoms
showed pink, (3) at petal-fall, (4) a fortnight later, and (5) two
months after 4. Bordeaux mixture 3-9-50 and 2-6-50 gave fairly
good control but caused considerable russeting of the fruit and
defoliation during the latter part of the season. The omission in
certain plots of the spray given a fortnight after petal-fall resulted
in severe secondary infection by Brooks’s spot (Phoma pomt)
and scab.

Two years of research (for the biennium ending June 30, 1921).—
Pennsylvania. Agric. Exper. Stat. Bull. 170, 31 pp., 1922.
[Ree’d 1923.]

The following references in the section of the report devoted to
botany and plant pathology (pp. 15-20) are of interest.

Root and ear rots of maize | Diplodia zeae, Gibberella saubinetii
and Fusarium moniliforme| cause a considerable reduction in the
annual yields of the Pennsylvania crops. The possibility of detect-
ing diseased ears by very carefully controlled germination tests has
been demonstrated. The results of field experiments in various
parts of the State showed an increase of about six bushels per acre

» 443

from healthy ears planted side by side with diseased ones (as
determined by the germinator). Such an increase, however, is not
regarded as sufficient to warrant the adoption of the geaminator
test as a part of the general farm routine [see also above abstract].
_ Co-operative investigations with the United States Department
of Agriculture, Bureau of Plant Industry, and Federal Horticultural
Board on the morphology and cytology of the causal organism of
potato wart disease (Chrysophlyctis endobiotica) [Synchytriwm
endobioticwm]| are being continued. Studies are also in progress
on the physiological and anatomical relations of various hosts to
the parasite; methods of control by the use of soil sterilization and
immune varieties; and the genetical behaviour of immunity and
susceptibility of potato varieties to this disease. Infection has not
been observed to occur in controlled soil temperature tanks above
22° C., indicating a relatively low temperature requirement.
Thirty-four American varieties, including Green Mountain, McCor-
mick, Cobbler, Spaulding Rose, and Burbank, were found to be
immune, and 63 out of 149 seedlings. Several varieties of tomatoes
have proved to be susceptible. Long-continued steaming of the
soil has been found to destroy the sporangia of the fungus, but this
method is impracticable for use on a commercial scale. Certain
chemicals are effective as regards complete penetration of the soil,
but the necessity of giving very heavy applications renders the cost
prohibitive.

The results of extensive observations on the incidence of wilt and
tuber rots of the potato in the warmer soils of Pennsylvania indicate
that at least three fungi, Fusariwm oxysporum, F. ewmarti2, and
Verticillium sp. are involved in the causation of these diseases.
The results of preliminary trials suggest that a large percentage of
infection in the field comes from the soil. Some difference in
the varietal resistance of plants inoculated in the field was
shown.

Field work on leaf roll of potatoes, begun in 1919, has shown that
the percentage of leaf roll in a field may increase in two years from
2.5 to as much as 100 per cent. By the practice of roguing early
in the season the percentage of leaf roll plants can be reduced but
in none of the trial plots was the disease entirely eliminated by
this method. Generally speaking, it does not pay to rogue fields
containing over 10 to 15 per cent. of leaf roll. Disease-free seed
should be secured whenever possible.

Winter blight of tomatoes, known in Australia as ‘spotted wilt’
and in Great Britain as ‘stripe’,is primarily due to a bacterial
organism [Bacillus luthyri] but unbalanced nutrition of the host
and a high degree of humidity were found to be predisposing
factors. Greenhouse tomatoes are principally attacked, though
outdoor ones may also suffer severely under certain conditions.
Conclusive proof of seed dissemination was secured.

The results of four years’ work on Septoria leaf spot [S. Lycoper-
sici| of tomatoes show that spraying with standard Bordeaux or
other copper compounds increases the total yield of fruits. Under
Erie County conditions it is not usually advantageous to spray
tomatoes for the canning market.

Three bacterial diseases of tomatoes appeared in Erie County ;

444

the first, apparently a seed-borne disease, resembles the ‘ Grand
Rapids disease ’, but the causal organism differs somewhat from
Aplanobacter michiganense [see this Review, ii, p.347]. The second
was identical with the canker reported from Michigan and
Indiana and recently attributed to Bacteriwm exitiosum Gard,
while the third was a wilt apparently caused by Bacillus solana-
cearum.

In 1915 a number of plots on a piece of ground thoroughly
infested with club-root of cabbage [Plasmodiophora brassicae | were
treated respectively with Bordeaux mixture, ammoniacal copper
carbonate, formalin, flowers of sulphur, and lump lime. Cabbage
was planted on these plots for six years in succession without the
treatment being repeated. The residual effect of the treatment was
most pronounced in the case of the Bordeaux mixture and lump
lime. By the end of the sixth season all the plots were again
infested and were treated with copper sulphate, Bordeaux mixture,
lump lime, milk of lime, ground limestone, lime-sulphur, and
nicotine sulphate. One year’s results indicate that Bordeaux mix-
ture (8-8-50), applied in amounts approximately equal to 3,200 lb.
calcium oxide per acre, is by far the most satisfactory. Lime-
sulphur proved extremely injurious.

Four years’ observations on Sclerotinia libertiana, the cause of
a ‘drop’ of lettuce and a storage rot of carrots and celery, show
that, if non-susceptible crops are grown for two years, the disease
will virtually disappear. The sterilization of the soil of frames
and seed-beds with formalin (1 in 100 at the rate of 1 gall. per
sq. ft.) is recommended. In 1918 two sprayings of lime-sulphur,
Bordeaux mixture, or Pyrox, gave satisfactory control of apple rust
[Gymnosporangium juniperi-virginianae], the first-named being
the most effective. In 1919, however, Bordeaux was best, whilst
sulphocide and sulphur dust (in 1920) were not satisfactory. Black
rot or frog-eye of apples [Physalospora cydoniae] can be effectually
controlled by the timely application of liquid sprays, dusts being
less satisfactory. Most of the infection usually occurs from the
time the leaves appear until three or four weeks after the fall of
the petals. All attempts to reproduce the disease by artificial
inoculation have failed. Apple blotch [Phyllosticta solitaria| was
well controlled by three applications of hme-sulphur, the first being
given 34 weeks after the fall of the petals. The results of pre-
liminary trials indicate that no infection takes place before
23rd May.

Wettes (C. G.), Identification of bacteria pathogenic to plants
previously reported from the Philippine Islands.— Philipp.
Journ. of Science, XX. 3, pp. 279-285, 1922.

The present paper, the first of a series in which all known
bacterial organisms pathogenic to Philippine plants will be briefly
described, deals with Bacterium solanacearum, Pseudomonas
phaseoli, Bact. malvacearum, and Bacillus nelliae sp. nov. After
a brief review of the records of these diseases in the Philippines,
the author describes in detail the cultural and morphological
characters of the organisms concerned. The media used were

ee i Lae

445

based on the American descriptive chart and in each case inocula-
tions were carried out to prove the pathogenicity of the organisms.

Bacterium (Bacillus) solanacearum was isolated from wilted
tobacco, eggplant, and tomato plants. The cells of the organism
measured 0-8 to 1-2 4 in length, Smith’s figures being 0-6 to 1-0 p,
and agreed in most cultural respects with the particulars previously
published (U.S. Dept. Agric. Div. Veg. Physiol. & Path. Bull. xii,
p- 1, 1896). Pseudomonas phaseoli was isolated from diseased
bean leaves, and the organism appears to be identical with that

’ described by Smith in 1901, both from the symptoms and the

tests, so far as they were comparable. Bact. imalvacearum,
isolated from young, watery lesions on cotton leaves, agreed with
the description of the organism by Rolfs (South Carolina Agric.
Exper. Stat. Bull. 184, p. 1, 1915), except that no difference in
degree of growth was observed on the various sugar media. The
bright yellow, non-pathogenic organism mentioned by Rolfs was
also encountered by the author in making the inoculations. The
bacterial wilt of parsley was for several seasons believed to be
caused by Bacterium solunacearum, the behaviour of the attacked
plants corresponding in all respects with that of those infected by
this organism. The result of physiological studies showed, how-
ever, that the organism was an entirely new species, which was
named Bacillus nelliae. The organisms are short rods with
rounded ends, 0-83 to 2-27 by 0:37 to 0-50 y, staining readily
with all common aniline dyes. The thermal death point lies
between 53° and 54° C. Three to seven peritrichous flagella were
demonstrated. Cultural characters are fully described.

THomAs (R. C.). A bacterial rosette disease of Lettuce.—UVhio
Agric. Exper. Stat. Bull. 359, pp. 197-214, 8 figs., 1922.

Since the autumn of 1919 a bacterial rosette disease of Grand
Rapids lettuce has been observed in a number of Ohio green-
houses. The losses caused by the disease, which in many respects
resembles that caused by Rhizoctonia, vary from a trace to 60 per
cent. of the crop.

Affected plants develop unevenly and show a tendency to rosette,
accompanied by a yellowing or flaccidity of the outer leaves,
especially at high temperatures. Examination of the roots showed
them to be seriously affected, the small fibrous roots rapidly ceased
to function, and the larger roots were readily detachable when
a plant was pulled up. The general cultural conditions prevailing
in the greenhouses were excellent.

A microscopic examination of the stems and roots revealed a
brownish substance, soluble in alcohol and acetic acid, in the xylem
and other portions of the vascular system, and in some cases
bacteria extended upwards from half an inch to an inch above ground
level. Isolation experiments readily yielded a single species of
bacterium, from dead rootlets and soil adhering to diseased plants.
Healthy lettuce plants inoculated with pure cultures of the organism
developed the typical symptoms of the disease. An inoculation
of the soil in which the plants were grown resulted in much
slighter infection but the organism was re-isolated from the diseased
rootlets and stems in the majority of cases.

446

The bacterium has never been observed to cause a rot or spots
on the leaves or stems of lettuce plants, and negative results were
obtained in every case when a suspension of the bacteria was
sprayed on the leaves of healthy plants. The chief action of the
organism appears to be to gain admission to the vascular system of
the plant and interfere with the free passage of food material.

The morphological and cultural characters of the organism are
described at length. The bacterium is non-motile, occurring singly
or concatenately, 1-4 to 1-9 by -5 to -85 yz or -9 to 1-5 by -4 to -8y
according to the medium, greenish-yellow, later olive-buff and
finally red in colour, strictly aerobic, optimum temperature for
growth 25° to 27° C., maximum below 38° C., minimum below 0° C.,
thermal death point 51° to 52°C., remaining viable in artificial
media and soil cultures for one year. The organism produced
ammonia and some indol, but no acid or gas. There is a marked
reduction of nitrates, in which the organism differs from Bact.
vitians Brown, the cause of a similar lettuce disease in South
Carolina. The bacterium is Gram negative, non-acid-fast, with-
stands desiccation for four days, and will grow in media made
alkaline with sodium hydroxide to 20 degrees Fuller's scale, and
in various acid-containing media. The group number of the
organism, for which the name Aplanobacter rhizoctonia n. sp. 1s
proposed, is 211-3333523.

Good results in the control of the disease were obtained by the
saturation of the soil, previous to planting, with formalin (8 to 33
pints to 50 galls. of water), applied at the rate of one or more
gallons of liquid per sq. ft. of surface area. The soil was allowed
to dry for a week or ten days before the lettuces were planted.

Nosktcourt (P.). Inoculations d’une bactérie phytopathogene a
des grenouilles. [Inoculations with a phytopathogenic bac-
terium on frogs.]|—Comptes Rendus Soc. de Biol., Ixxxviut,
13, pp. 1041-1042, 1923,

Inoculation experiments with pure cultures of Bacillus carotovorus
Jones, isolated from a lettuce in July 1922, were recently carried
out on five frogs, all of which died after periods ranging from six
to fifty-one days. The animal which survived longest was in-
oculated with a culture previously heated in order to kill the
bacillus. Pure cultures on bouillon of the organism isolated from
the dead frogs behaved in all respects like the original cultures and
produced the symptoms of rapid decay in carrots. Thus the
phytopathogenic properties of the bacillus were in no way impaired
by its passage through the animals. The fact that Bacillus caroto-
vorus has been proved to be zoopathogenic as well as phytopatho-
genic is regarded as important from the standpoint of comparative
pathology.

ALLYN (O. M.). Reducing Corn root-rot by careful hand selection
of seed.— Journ. Amer. Soc. Agron., Xv, 2, pp. 73-76, 1923.

In Illinois during the spring of 1922 a number of apparently
healthy ears were found in a stock of 400 bushels of Western
Ploughman seed maize, a smooth variety with blocky kernels, and
it was decided to test by germination experiments in the laboratory

ieee

: 447
and by planting in the field [see above p. 442] the relative merits of
the ears showing no disease, of those going into the general run
of seed, and of those badly diseased, the ears being grouped into
these three grades before shelling.

Composite samples for germination tests were taken from the
bags after shelling, both the plate and blotter, and rag doll methods
being used. In each test 200 kernels were placed in a germinating
cabinet at a temperature of 80° F. and dissected and examined
after seven days. The results of all the tests may be summarized
as follows: selected seed gave 91-1 per cent. healthy and -96 per
cent. dead, ‘general run’ seed 69-7 per cent. healthy and 3-7 per
fee dead, and diseased seed 52-3 per cent. healthy and 12-5 per cent.

ead.

When samples of the above seed were planted on a comparatively
new piece of ground, the following yields were obtained: selected
seed, 73-7 bushels shelled maize per acre; ‘general run’ seed, 65-8
bushels ; diseased seed, 64-2 bushels. The largest number of disease-
free ears (67-6 per cent.) came from the selected plot: 31-2 per cent.
from the * general run’, and 13-8 per cent. from the diseased plot.
These results show that careful hand selection materially reduces
root rot | Diplodia zeae] even in the first year.

Rosen (H. R.). A bacterial disease of Foxtail (Chaetochloa lutes-
cens).— Ann. Missowr, Bot. Gard., ix, 4, pp. 333-385, 7 pl.
(2 col.) 1 graph, 1922. [Rec'd 1923.]

A bacterial disease of foxtail, first recorded by the author in
Arkansas in 1919, has since been studied in more detail especially
with regard to its symptoms and etiology. No systematic attempt
has been made to discover the disease on other grasses, but the
results of artificial inoculation experiments show that the pathogen
can infect wheat, oats, rye, barley, maize, Sudan grass (Holcus
sorghum sudanensis), millet, and perennial foxtail. On oat and
barley seedlings the disease may cause serious damage.

The lesions on foxtail appear as ight or dark brown spots of no
definite size or shape; they are most frequently found on the
blades and sheaths. On other hosts the symptoms vary from light
yellow, indefinite areas (often with a reddish tinge in the case of
oats) to greyish-green, withered spots. The invaded tissues swarm
with bacteria which cause discoloration, disintegration, and finally
death. The organism was not difficult to isolate and artificial
inoculations were readily successful when the bell jars used were
properly aerated. Temperature plays an important role in infec-
tion, which does not occur on plants incubated below approximately
21°C., whilst above 24° C. infections are effected, and about 32°C.
the symptoms appear in 24 to 48 hours. Admission is gained by
means of stomata and water pores.

The disease appears to be different from any other known
bacterial affection of grasses. The causal organism, Pseudomonas
alboprecipitans n. sp.,is described as follows: narrow rods with
rounded ends, solitary or in pairs, averaging 0-6 by 1-8 yu, motile by
a single polar flagellum; no spores, zoogloea, or irregular forms ;
capsules present; strictly aerobic; surface colonies on nutrient agar
white, round, raised, smooth, amorphous, sticky, margins entire,

=

448

surrounded by colourless areas followed by a white precipitate on
media testing acid as Py 6-6; nitrates reduced to nitrites; ammonia
produced, but no indol, hydrogen sulphide, acid, or gas; diastatic
action strong; fair growth in Uschinsky’s and Fermi’s solutions ;
minimum temperature for growth 0°C., optimum 30° to 35°C.,
maximum about 40°C., thermal death point 41° to 48°C.; not
sensitive to drying or freezing and only slightly so to sunlight;
Gram negative, non-acid-fast. The group number is 5822-31220-
1333.

The meaning of hydrogen-ion concentration, its relation to
titratable acidity, the methods of measuring it, and the necessity
of utilizing it in the study of bacterial pathogens are discussed.
Comparisons are given between Fuller’s scale and Py values.
Numerous cultural reactions are presented, and the relationship of
various organic anions to growth and several questions of technique
are discussed.

Beef extract was found to be the probable source of the white
precipitate (a phosphate) in media: containing the extract.

A bibliography comprising nearly a hundred titles is appended.

Munro (D. G.) & SUNDARARAMAN (S.). Coffee-spraying experi-
ments.—Planters’ Chron., xviii, 14, pp. 193-196, 1923.

A series of experiments was undertaken at the Purchikadu
(Sidapur) estate [India] to ascertain (a) to what extent leaf diseases
of coffee, such as red rust (Hemileia vastatriz) and black rot
[Corticiwm koleroga] could be checked by spraying; (b) the opti-
mum strength of solution for efficacy and economy ; (c) the efficacy
of different kinds of adhesives when added to Bordeaux mixture;
and (d) whether the improvement in the health of the plant and the
gain in yield compensated for the cost of the work. The spraying
was carried out in May to June 1922 under adverse weather con-
ditions, the experimental area being divided into plots of about one
acre in extent. The results may be summarized as follows. Two
per cent. Bordeaux mixture 10-10-50 with resin adhered well to the
leaves and caused no injury to the foliage, whilst almost equally
good results were obtained by the use of half strength Bordeaux
(5-5-50) plus resin or casein, and even quarter strength Bordeaux
(24-21-50) with resin or casein, was also very satisfactory. Casein
is recommended as cheaper and easier to manipulate than resin soda.
Fish oil soap was found not to be a good adhesive. Lime-sulphur

1_71_50 was washed off the leaves by the heavy rains of the
monsoon.

The value of the treatment may be gauged by the fact that the
leaves produced in the April to May (1922) flush remained on the
sprayed trees till February 1923, by which time the trees in the
unsprayed controls had lost nearly all the leaves of the September
flush. Die-back was much less prevalent in the sprayed than in
the untreated plots.

Spraying is both difficult and expensive especially where water
is scarce. Large sprayers are unsuitable, and the frequent filling
of small ones, together with the preparation of the mixture, entails
considerable time and care. The time for spraying is limited by
climatic conditions to about four weeks from Ist May to 1st June.

449

Efforts are being made to obviate the various difficulties in
connexion with the treatment by devising a dry fungicide which
can be dusted on the plants either in a heavy dew or light
shower of rain.

BriToN-JONES (H. R.). A wound parasite of Cotton bolls —WMin.
Agric. Egypt Tech. and Sev. Serv. (Bot. Sect.) Bull. 19, 8 pp.,
2 pl. (1 col.), 1923.

Black mould (Rhizopus nigricans) causes a severe rotting of the
bolls of Indian, American, and native varieties of cotton in Upper
and Lower Egypt.

The fungus, a common facultative parasite, gains admission to
the plants through the wounds made in the bolls by the attacks of
the pink boll worm (Gelechia gossypiella) and the boll avorm
(Earias insulana). Two days after infection the boll becomes soft
and turns reddish-brown or greenish-black. At this stage a slight
touch will cause the boll to break off at the junction between the
base of its stalk and the main axis. Two or three days later the
boll hardens and dries up, thereby causing a premature splitting
along the sutures. The stem immediately under the affected boll
also turns reddish-brown, becomes shrunken and hard, and is not
readily detached by contact or by the wind. The boll does not
open out completely and the production of numerous sporangia by
the fungus imparts an olive-green or dirty appearance to the fibre.
The bolls thus affected have been described by Willcocks as
‘Mabroom’ bolls (Sultanic Agric. Soc., ‘The insect and related
pests of Egypt,’ i, 1916).

The disease is most prevalent from the latter part of June
onwards and reaches its climax during the late summer, which is
the period of the maximum activity of the boll worms. The
atmospheric humidity caused by the advance of the Nile flood at
this season also contributes to the rapid growth of the fungus.

In 1920 out of 10,537 bolls examined at the Giza Experiment
Station, 795 were attacked by R. nigricans and in 785 of these the
fungus was associated with the boll worm. By inducing premature
opening of the bolls the fungus facilitates the entry of the cotton
seed bug. Infected bolls cannot be saved and the disease can only
be controlled by preventing the attacks of the boll worm.

An important question which arises in connexion with the attack
of R. nigricans is the relation between the fungus and the boll
worm, but at present this relationship is merely a matter of con-
jecture.

Pape (H.). Ein neuer, auf Schneegléckchen (Galanthus nivalis

L.) schmarotzender Brandpilz (Urocystis galanthi n. sp.).

A new smut (Urocystis galanthi n. sp.) parasitic on the snow-

rop (Galanthus nivalis L.).]|—Arb. Biol. Reichsanst. fiir
Land- und Forstwirtsch., xi, 4, pp. 331-336, 7 figs., 1928.

In January 1921 the leaves, leaf-sheaths, and spathes of snow-
drops collected from a garden near Berlin for experimental purposes
were found to be partially or totally covered with lead-coloured,
callus areas, measuring 5 to 50 by 3 to 5 mm. Closer examina-
tion revealed the presence of the mycelium of a species of

K

450

Urocystis, dark brown spore masses being formed in the parenchy-
matous tissues of the leaves. The spore balls consisted of one, two,
or occasionally three or four primary spores in the centre, and
numerous secondary spores situated at the periphery. They were
globular to ellipsoid and measured 23 to 51 y across, whilst the
primary spores averaged 14 by 2ly. When fully developed the
secondary spores formed a firm, single, compact layer of smooth,
light-brown spores, 7 to 14 in diameter and globular to irregular
in shape.

The hyphae, which were about 4, in breadth, hyaline, and
intercellular, were detected only in the tissues surrounding the
spore balls. Here and there, ramified or lobed haustoria were pro-
duced. The intercellular spaces were much enlarged by the
formation of the spore masses.

Attempts to germinate the spores were unsuccessful, probably
because the resting period allowed was not long enough. Natural
infection of the snowdrop appears to take place in the very early
spring, the fungus probably remaining quiescent during the
following summer, autumn, and winter. ‘The presence of the
fungus in the first shoots of the plant indicates that it overwinters
in the bulb.

The snowdrop smut is in all probability closely related to
Urocystis lewcoji Bubak, which attacks Leucojwm vernum, another
member of the Amaryllidaceae, and to U. colchici, which is found
on numerous Liliaceae. The snowdrop parasite, however, differs in
various morphological particulars from the published descriptions
of U. leucoji and U. colchici (a comparative table of which is given),
and the creation of a new species, U. galunthi, is believed to be
justified.

Ware (W. A.). Violet felt rot (Rhizoctonia) of Clover.—Journ.
Min. Agric., xxx, 1, pp. 48-52, 6 figs., 1923.

So far as the author is aware, this is the first record of the
occurrence of Rhizoctonia violacea on red clover in England,
although it has already been described as attacking this host on
the continent. The fungus is well known as causing injury to
many other cultivated plants, such as seakale, carrots, potatoes,
lucerne, &c., but it has yet to be proved whether it can pass from
other host species to clover, or whether specialized races or forms of
the fungus exist.

The disease was first noticed at the end of November 1922 in
a field of red clover attacked by stem rot (Sclerotinia trifoliorum),
but it was quite evident that Rhizoctonia was present as a parasite
on the clover, and was not merely saprophytic on plants or parts of
plants previously killed. Whether primary infection was aided by
the mild conditions prevailing in the early winter of 1922 is not
known ; it is possible that the occasional frosts were responsible for
stirring into activity the dormant sclerotia of the Rhizoctonia
which may have been present in the soil. The Rhizoctonia was
first recognized on the stubble of the previous oat crop, the violet-
brown mycelium being fringed with white at its growing extremity.
Affected clover plants were dwarfed and stunted and frequently
showed the leaves in a dying condition. On digging up and

ee ee a ee

451

carefully washing attacked plants the violet-brown mycelium
could be seen just at and below the soil level.

The fungus attacks the main root and its branches, covering
them with minute, twisted, brown strands, and penetrating the
outer cork layers of the root at various points, forming sclerotial
bodies [corps miliaires, infection cushions] which may possibly
function also as suckers. The layers in contact with these sclerotia
are apparently killed and the rot proceeds until the whole of the
main root system is involved.

The plants, in the majority of cases, make an effort to recover by
developing adventitious roots from the base of the crown, and
under favourable conditions the effort may be successful, the new
root system not being observed to be attacked. In addition to the
killing of a certain number of plants, however, patches of the clover
may be retarded, dwarfed, weakened, and somewhat thinned.

Besides red clover, the Rhizoctonia was found attacking living
plants of corn mint (Mentha arvensis), meadow grass (Po), speed-
well (Veronica agrestis), and a dead plant of knotgrass (Polygonum
aviculare), but in none of these cases were sclerotia found.

No experiments in the control of the disease on clover have yet
been made. Having regard, however, to the probability of the
sclerotia set free in the soil remaining dormant for some years, it is
suggested that infected soil should be given as long a rest from
clover as possible, an interval of over eight years being advisable.

PurrERItut (V. A.). Silver leaf disease of fruit trees and its
occurrence in South Africa.— Dept. of Agric. S. Africa, Bull.
27,19 pp., 10 figs., 1923.

Silver leaf in South Africa is making headway, chiefly owing to
the indifference shown to the disease by growers. The two types,
‘false’ silver leaf, due to physiological causes and often of a non-
permanent character, and true silver leaf due to the parasitic fungus
Stereum purpureum, are mentioned and a description of the
symptoms and effects of the latter is given.

The disease has been reported from different parts of the Union,
but as silvering of the foliage was the only diagnostic character
available, many of the cases must be referred to false silver leaf.
A fungus found on peach trees near Pretoria and on an unknown
host at Maritzburg, Natal, could not be referred to S. purpurewm
with absolute certainty. In the Western Cape Province true silver
leaf disease has occurred at Stellenbosch, Wynberg, and Paarl, on
plums, apricots, peaches, and sometimes on apples.

The fruiting bodies of the fungus occur more rarely in South
Africa than in England, probably owing to the climatic conditions
and also perhaps to different methods of planting and culture,
which in South Africa are not favourable to fungal development.
On the other hand, the virulence of S. purpurewm may increase
with time, as has been the case with Schizophyllum commune.
Fruiting bodies of S. purpurewm have been found on Populus alba
near Capetown, and observation has shown that fruit trees in close
proximity to poplars constantly develop silver leaf. As the latter
trees are generally grown in damp situations, the ready fruiting of
the fungus on them is only to be expected. The identity of the

oe Me

i ee

a

4.52

South African fungus was confirmed by British workers as S. pur-
pureum, although some of the specimens sent bore hairs on the
hymenium, a characteristic of S. rugostusculum, which species,
however, is now held to be not specifically distinct.

In South Africa very little is known about the relative suscepti-
bility of the different varieties. Of plums, Kelsey seems particu-
larly susceptible. Generally speaking, plums and peaches appear
to suffer more than other fruit trees, but inoculation experiments
on apricots, apples, and pears were also successful, while the results
on loquat were doubtful.

The control measur s recommended consist of the cutting out
and burning of all discoloured wood including the branches which
show silvering, the pruning tools being dipped in a 10 per cent.
solution of formalin after use. Large pruning wounds should be
pared and treated with Stockholm tar or some good paint. As the
disease is supposed to make more rapid headway in heavy soils and
in damp situations, liming must not be neglected.

There are no legislative regulations in South Africa similar to
those in force in England regarding this disease, but it is in the
growers’ own interests to take energetic measures to control it.

Plant diseases in the Western Cape Province VII. Silver leaf
disease of fruit trees.—Journ. Dept. Agric. S. Africa, vi, 3,
pp. 2338-236, 4 figs., 1923.
This is a more popular account of the disease discussed in the
preceding paper.

Bore (J.). Cultivation and diseases of fruit trees in the Maltese
Islands.— Govt. Printing Office, Malta, 622 pp., 1922.

This valuable compilation deals with the cultivation and diseases
(due to fungi, insects, and physiological causes) of the following
Maltese fruit and nut trees: citrus (eight varieties), olive, carob
(Ceratonia siliqua), fig, black and white mulberry, pomegranate,
pear, apple, medlar, Azarola thorn (Crataegus azarolus), almond,
peach and nectarine, plum, apricot, cherry, walnut, pistachio
(Pistacia vera), stone or edible pine (Pinus pinea), kaki or Chinese
date plum (Diospyros kak), banana, prickly pear (Opwntia ficus-
indica), date palm, vine, gooseberry, currant, raspberry, and straw-
berry. Various other trees are mentioned but the diseases
attacking them are not of sufficient importance to justify enumera-
tion. The cultivation and diseases of the vine are discussed at
considerable length, and throughout the book there are many
useful suggestions on control measures and the application of
appropriate cultural methods.

GossarD (H. A.) & WALTON (R. C.). Dissemination of fireblight.—
Ohio Agric. Exper. Stat. Bull. 357, 126 pp., 14 fig., 1 diag.,
1922.

These investigations, commenced in 1915, were carried out to
elucidate the spread of the fireblight organism (Bacillus amylo-
vorus). It was first found that this organism was capable of living
in honey for 72 hours or more. Apple twigs inoculated with honey
drawn from three different hives developed fireblight and from two

oie

453

of the twigs the fireblight organism was recovered. Tender twigs,
inoculated with apple pollen removed from the baskets of bees
caught as they were entering the hive, died in several cases, pre-
sumably from fireblight, though the organism was not isolated.
Mouthparts of bees, caught during the blossoming period and
inserted into tender twigs, resulted in the death of the latter,
almost certainly from fireblight, though again the organism was
not recovered. The results of further tests showed that the organism
was capable of living in aphid honey dew for seven days, and in
peach, plum, and cherry nectar for five days or longer. The records
showed an average of 64-5 per cent. infection of the nectar from
peach blossoms, 74 per cent. from plum, and 94 per cent. from cherry.

Rain was proved to be a most important agent for the spread of
infection over trees where centres were already established, especi-
ally if these were near the top. It was estimated that 50 to 90 per
cent. of all blossom infection is accomplished by rain water.

Susceptibility to fireblight was shown to be greatly reduced in
blossoms pollinated 72 hours previously, while blossoms 144 hours
after pollination were immune from the disease. From this it may
be inferred that the presence of bees in an orchard is desirable, since
they hasten the flowers past the period of susceptibility to fire-
blight, and it is advisable therefore to encourage pollination before
the blight wave sets in. In one case the initial infection of a
young pear orchard was found to have originated through blossom
blight.

Several sucking and boring insects were observed to be carriers
of tireblight, and in general it may safely be stated that any con-
taminated insect, either of the biting or sucking class, is a potential
insect of transmission. Attempts to prove that ants were respon-

sible for spring infection on a large scale met with negative results,

as also did the attempted isolation of the blight organism from the
bodies of aphids, aphid wax, and syrphid larvae taken from living
blight cankers. The possibility of the organism surviving in
the intestinal tract of bees appears so remote as to be negligible.

The application of the ultra-violet rays to leaves and twigs
to test their destructive action on the fireblight organism gave
negative results.

The writers believe there is ample ground for suspecting that tire-
blight travels northward with the zone of blossoming more exten-
sively than is generally accepted.

Directions for spraying fruits in Ilinois.—J//inois Agric. Exper.
Stat. Circ. 266, 15 pp., 2 figs., 1923.

The standard sprays used in the control of fungous diseases of
Illinois fruit are described in the present paper, which is particu-
larly designed to meet the requirements of smallholders.

Apples. (1) Dormant spray of lime-sulphur or oil emulsion
primarily for the control of San José scale; (2) cluster-bud
spray of lime-sulphur (14, or 4 lb. dry, in 50) and lead arsenate
(2 lb. paste or 1 lb. powdered), chiefly for the control of scab
| Venturia inaequalis|; (3) calyx spray, similar to 2 and applied
for the same purpose; (4) one week after petal fall as in 2
and 3; (5) a fortnight after fall of petals; same formula as 2, 3,

qutiuniiaden ae

454

and 4. for the control.of blotch [Phyllosticta solitaria], scab, codling
moth, curculio, and leaf spot [Physalospora cydoniae|; (6) three
weeks after fall of petals: same formula and objects as 5; (7) four
weeks after fall of petals (for blotch only): same formula as above,
minus the lead arsenate; (8) five weeks after fall of petals: as in 7.
Wherever attacks of bitter rot [Glomerella cingulata] are antici-
pated, four applications of Bordeaux mixture should be given at
intervals of ten days from the first week in July.

Cuerrigs. (1) Lime-sulphur (1, or 241b. dry, in 50) and lead
arsenate (3 lb. paste or 14 powdered) for the prevention of brown
rot [Sclerotinia cinerea], leaf spot [Coccomyces h iemalis|, and
curculio, to be applied just before the opening of the buds; (2)
similar to 1 and for same reasons, to be given immediately after
fall of blossoms; (8) as preceding, to be applied as above, ten days
after 2 in case of damp, close weather only.

Peacues. (1) Dormant lime-sulphur spray (53, or 15 1b. dry,
in 50), for the control of San José scale and leaf curl [Hzoascus
deformans], to be applied in late autumn or early spring; (2) four
weeks after fall of petals, self-boiled lime-sulphur (8-8-50) and
lead arsenate (3 lb. paste or 14 powdered) for the control of scab
[Cladosporium carpophilum|, brown rot [Sclerotinia cinerea], and
curculio; (3) for midseason and late varieties, another application,
as in 2, should be given against brown rot from four to five weeks
before the fruit ripens; (4) in the event of damp, close weather, an
additional lime-sulphur (8-8-50) spray should be applied a fortnight
before picking.

Pears. (1) Dormant spray as for apples; (2) cluster-bud spray
as for apples for the control of scab | Venturia pirina] and cureulio ;
(3) calyx spray as for apples for control of scab, codling moth, and
curculio; (4) three weeks after fall of petals for the control of
smudge and insects: as in cluster-bud spray for apples.

Puums. (1) Dormant spray as for apples; (2) as in first summer
spray of cherries for the control of leaf diseases, brown rot [Sclero-
tinia cineren|, and curculio: (3) and (4) same as 2, to be applied
immediately after blossoms fall amd ten days later respectively ;
(5) additional applications of lime-sulphur lead arsenate should
be given at fortnightly intervals until a month before picking in
wet seasons.

Brameues. Anthracnose of black raspberry [Gloeosporium
venetwm]| may be controlled as follows: (1) lime-sulphur (1 in 20)
applied before growth starts in spring; (2) lime-sulphur (1 in 40)
when new shoots are 6 to 8 inches high: (3) lime-sulphur (1 in 40)
just before blossoming.

CURRANTS and GoosEBERRIES. Spraying for leaf spot [Myco-
sphaerella yrossulariae| should begin when the leaves are untold-
ing and be repeated at fortnightly intervals until five applications
have been made, Bordeaux mixture being used. Gooseberry mildew
[Sphaerotheca mors-uvae] may be controlled by six applications of
liquid lime-sulphur (1 in 40) given at ten-day intervals from the
opening of the buds.

Graves. Most diseases can be combated by a combination
spray of Bordeaux mixture and lead arsenate applied at the follow-
ing times: (1) as the leaf buds are opening; (2) immediately after

455

fall of bloom; {3) ten days after fall of bloom; (4) twenty days
after fall of bloom. The last two applications should be of double
strength lead arsenate.

STRAWBERRIES. Leaf spot | Mycosphaerella fragariae| may be
controlled by spraying with Bordeaux mixture (1) as the plants
begin growth; (2) just before blossoming; and (3) just after
blossoming.

Full directions are given for making and mixing the standard
sprays.

GARDNER (M. W.). Apple blotch control.—Tvrans. Indiana Hort.
Soc. 1921, pp. 184-185, 1922. [Rec'd 1923.]

Apple blotch | Phyllosticta solitaria| is gradually spreading north-
wards in Indiana. The most reliable fungicide for its control is
Bordeaux mixture 4-4-50 or 46-50, but lime-sulphur may be
substituted in cases of varieties liable to russeting, such as Ben
Davis. Sulphur and Bordeaux dusts reduce infection to some
extent but are not so efficient as liquid Bordeaux. The best results
are secured by the 2-4-6-10 week schedule. In planting new
orchards the use of susceptible varieties, such as Northwestern
Greening, should be avoided.

FisHer (D. F.). Spoilage of Apples after harvest.—Rept. Proc.
Thirty-second Ann. Convention Brit. Columbia Fruit-Growers’
Assoc. held at Victoria, B. C. 18th to 20th Jan. 1922, 68 pp.,
1922.

Storage diseases greatly reduce the harvested crop of apples
and at the same time increase the cost and risk of market opera-
tions. It is almost impossible to form any conception of the
importance of these diseases unless the fruit can actually be traced
to the ultimate consumer, but certain useful data may be collected
' from the records of the United States Bureau of Markets. The
terminal markets’ inspection reports indicate that in 1919, out of
2,973 cars examined 23-7 per cent. were infected with blue mould
(Penicillium expansum), representing the parasitic group of storage
diseases, and 1-6 per cent. with scald, one of the principal physio-
logical affections of stored apples. In 1920, of 3,462 cars examined
60-6 per cent. were infected with blue mould and 13-3 per cent.
with scald.

P. expanswum is normally incapable of penetrating the unbroken
skin of the fruit and does little harm to the crop on the trees,
although it has been observed to do so following injury by codling
moth. In commercial storage and in transit it probably causes 80
to 95 per cent. of the total rots, while in the local markets and
home storage the losses are estimated to exceed 10 per cent.

The fungus most frequently enters through stem punctures, but
sometimes through finger-nail scratches by pickers, insect injuries,
scab spots, bruises and all kinds of wounds. The disease may
spread from one apple to another by the dissemination of the
spores or by actual contact. Low temperatures greatly delay the
development of the mould, more particularly at the inception of
decay than during its later development, rots starting while the
apples were warm, developing rapidly even at 32° F. The losses

456

from the disease may be greatly minimized by careful handling,
early cooling of the apples to 32° F., and securing sanitary condi-
tions in the packing houses.

Apple scald causes more losses than all the other [physiological]
storage diseases combined, being particularly severe on York
Imperial, Grimes, Black Twig, Arkansas Black, Rome, and Stayman.
It can be distinguished from all other apple diseases by its prefer-
ence for the greener side of the fruit, the flesh of which is sometimes
decayed to a depth of half an inch.

The influence of temperature on the production of scald has been
demonstrated experimentally. In general, apples held at 60° to
70° F. scald three to four weeks earlier than those held at 50°;
those at 50° about four weeks earlier than those at 40°; and those
at 40° about three weeks earlier than those at 32°. The higher
temperatures are frequently encountered in cases of delayed storage.
The time immediately following picking is a critical period during
which refrigeration is urgently required. There are, however,
other factors besides temperature to be considered. The green
portion of the skin is most susceptible to scald, and measures to
secure proper colouring of the fruit are desirable.

Investigations have also been carried out which indicate that
humidity has no effect upon the development of the disease except
where actual drops of moisture form on the apple, when probably
the harmful effects are primarily due to the partial exclusion of the
air or the retention of oxidation products by the apple. The ex-
periments demonstrated that accumulations of carbon dioxide
(1 to 6 per cent.) tend to prevent, rather than promote the develop-
ment of the disease, and apples susceptible to scald were rendered
immune by storage for a few days in an atmosphere of pure carbon
dioxide.

The conclusion was also reached that abnormal respiratory con-
ditions consequent upon poor aeration are largely responsible for
scald. It was shown that a constant air movement of from one
eighth to one quarter of a mile per hour either entirely prevented
scald or reduced it to a minimum. The intensity of the air move-
ment was apparently more important than its continuity, and the
circulation of the air more important than its renewal. Thorough
aeration during the first eight weeks of storage was of much more
value than later.

These results show that scald is due to some product which can
be carried away by air or possibly taken up by absorbents. Further
tests in which apples were enveloped in paper impregnated with
various gas-absorbing substances (paraffin, vaseline, and olive oil),
or surrounded by sawdust, animal charcoal, or corn starch, gave
convincing evidence that scald can be prevented by the absorption
of the gases (other than carbon dioxide) given off by the apples
themselves. The odorous constituents of the apple were suspected
and experiments showed that typical scald effects could be produced
by exposing the fruit to the esters of amyl acetate and amyl
formate.

On the whole the treated wrap method, which provides each
apple with its own preservative, appears to be the best and most
reliable preventive of scald. Further experiments are in progress

457

to ascertain the relative efficiency of the various mineral oils and
the exact quantities required.

Lupwics (K.). Bericht wtber das Auftreten der Spitzendirre
(Monilia) bei Kirschen in der Provinz Brandenburg im Jahre
1922. |Report on the occurrence of withertip (Monilia) of
Cherries in the Province of Brandenburg in 1922.]— Deutsche
Obst- und Gemiisebauzeit., 1xix, 12, pp. 91-92, 1923.

The replies to a circular letter of inquiry issued by the Branden-
burg Chamber of Agriculture in co-operation with the Plant Pro-
tection Head-quarters at Dahlem, Berlin, indicate that, in general,
the Monilia disease of cherries was much less severe in Branden-
burg in 1922 than for some years previously. It is believed that
the drought of 1921, which allowed of a complete ripening of the
wood of young shoots, was largely responsible for the comparative
absence of the disease. The brief duration of the blossoming
period in 1922 was also unfavourable to the fungus.

The following varieties were generally resistant: Friiheste der
Mark; Hedelfinger Riesenkirsche, Grosse Prinzess, Konigsknupper,
Gassin’s Herz, Saure Natte, Ostheimer Weichsel, Kénigin Hortense,
Guben’s Ehre, and Podbielski; whilst susceptible varieties were
Shade Morello, Doppelte Natte, Grosse Gobet, Rote Glaskirsche,
Ochsenherzkirsche, and Diemitz (slightly). Treatment with lime-
sulphur mixture or solbar was reported to be more efficacious than
the application of Bordeaux mixture or carbolineum.

HO6sTERMANN (G.) & Noack (M.) Das Rutensterben der Himbeeren.
[The die-back of Raspberry canes.] — Deutsche Obst- wid
Gemiisebauzeit., xix, 20, p. 153, 1923.

The die-back of raspberry canes caused by Didymella applanata
[see this Review, ii, p. 128] is constantly increasing in severity and
a particularly virulent form of the disease, resulting in the produc-
tion of ‘witches’ brooms’ on the canes, has been observed in some
parts of central Germany. None of the well-known varieties
appears to be immune froin the disease, which may be controlled
to some extent by spraying the young shoots with solbar or
Bordeaux mixture, liming the soil, using artificial fertilizers in
preference to fresh organic manure, and by removing and burning
diseased shoots.

It is recommended that nursery gardeners and other purchasers
of raspberry canes should insist upon guarantees to the effect that
the material is free from die-back.

GRAULUND (R.). Ein gutes Mittel gegen den amerikanischen
Stachelbeermehitau. |A good remedy for American Goose-
berry mildew. ]|—Deutsche Obst- wnd Gemiisebawzett., |xix, 21, p.
163, 1923.

At Eskilstuna (Sweden) the American gooseberry mildew
[Sphaerothecu mors-uvae| has been successfully combated by the
application of a 6 to 7 per cent. solution of the best quality of soft
soap at the rate of 2 to 3 litres per bush. The soft soap solution
completely destroys the conidial stage of the mildew but not the
perithecial stage. Vigorous young bushes require repeated sprayings

458

during the summer, but for mature bushes one application given in
the evening or when the sky is overcast, usually suffices. Very
occasionally a negligible russeting of the foliage or dropping of the
fruit may ensue.

Rose mildew [Sphaerotheca pannosa] has been controlled by 3 to
4 per cent. solutions of the same material.

TISDALE (W. H.), TayLor (J. W.), & GrirrirHs (Marion A.) Ex-
periments with hot water, formaldehyde, copper carbonate
and chlorophol for the control of Barley smuts.—Phytoputh.,
xii, 4, pp. 153-160, 1923.

The results obtained by the use of various seed treatments for the
control of loose smut (Ustilago. nuda) and covered smut (U. hordei)
of barley are given in this paper.

Experiments begun in the autumn of 1919 on three varieties of
barley, in which “seed was either (1) presoaked 4 to 6 hours,
immersed in water at 52°C. for 10 minutes and then dried, (2)
immersed 10 minutes in formalin (1 in 320), covered overnight and
spread to dry, or (3) sown without treatment, were interesting, as
the second treatment produced plants as free from loose smut as
the hot water treatment, normally used against this disease.

Similar experiments were carried out in 1921 and 1922 using five
varieties of barley. Full figures regarding these experiments are
given. They show that formalin was just as effective in controlling
loose smut as the modified hot water treatment (0-1 against 0-15
per cent. infection) whilst it is less effective against covered smut (4-4
against 2-16 per cent.) for which it has been recommended. Little
was gained in the yields, however, by either treatment. Varieties
differ in their response to the treatments, which might be recom-
mended for some and not for others.

In the autumn of 1921, chlorophol, an organic mercury com-
pound, and copper carbonate were tried on heavily smutted seed
and the results of the year’s trial were striking. Copper carbonate,
though favourable to the germination of the seed, did not satis-
factorily control either of the barley smuts, whilst chlorophol was
very effective, reducing the percentage of loose smut from 0-82 to
0-15 and covered smut from 5-08 to 0-45 and causing increased
germination.

HEALD (F. D.), ZuNDEL (G. L.), & BoyLe (L. W.). The dusting of
Wheat and Oats for smut.—Phytoputh., xiii, 4, pp. 169-183,
1 fig., 1923.

In this paper the authors give results obtained in the control of
bunt of wheat [7T%letia tritici and T. levis], some of which have
been pr eviously noticed [see this Review, ii, p. 264], and also figures
relating to the efficiency of copper carbonate in controlling oat smut
(Ustilago lewis).

The new experiments recorded on Sone consisted of a series
of farm ‘demonstrations to show the comparative effect of copper
sulphate, formalin, and copper carbonate in the control of bunt
carried out in 1921-22. In the autumn of 1921 over 10,000 aeres in
Washington were seeded with wheat treated with copper carbonate
(2 oz. per bushel) and the results compared with those of the farmers’

459

own treatment with copper sulphate or formalin. The average
percentages of bunt for the various treatments were as follows :—-
copper sulphate 10-9, copper carbonate 7-2; copper sulphate +
lime afterbath 11-0, copper carbonate 8-5; formalin 9-1, copper
carbonate 3-1; formalin + lime afterbath 10-2, copper carbonate 3-4.
Seed treated with copper carbonate germinated 1 to 5 days earlier
than normal and there was very little seed injury, whilst with copper
sulphate and formalin severe injury resulted in a number of cases.

In the first experiment against oat smut, carried out in the
spring of 1922, five field demonstrations were made to test the
comparative value of the standard treatment and copper carbonate
2 oz. per bushel. The average percentage of smut in the five
demonstrations were as follows: untreated 8-9; formalin 0-20;
formalin + lime afterbath 1-10; copper carbonate 1-17.

In a second experiment against oat smut, artificially smutted seed
of the varieties Swedish Select, Abundance, and Chinese Hull-less
was treated with copper carbonate at the rate of 2 0z.,3 0z., and
4 oz. per bushel, and the average percentages of smutted panicles
were 3-01, 2-14, and 2-26 respectively whilst the control gave 39-12.
The most striking figures were obtained with the hull-less variety,
Chinese Hull-less, for which the figures were 0, 0, 1-00 and the
control 70-45. The use of 2 oz. copper carbonate gave practically as
good control as larger amounts. The protection afforded by copper
carbonate, however, was not equal to that ordinarily obtained with
standard formalin treatment.

Fraser (W. P.) & Srmmonps (P. M.). Co-operative experiments
with copper carbonate dust and other substances for smut
control.— Scient. Agric., 11, 9, pp. 297-302, 1923.

In 1922 a series of experiments in the control of bunt of wheat
(Tilletia tritici and T. levis) was conducted at the Saskatchewan
Laboratory of Plant Pathology, in co-operation with the Dominion
Experimental Farms at Indian Head, Scott, and Rosthern (Saskat-
chewan), and Lacombe (Alberta). At Indian Head the treatments
were also tried on oats against smut (Ustilago levis). The treat- -
ments tested were (1) formalin, 1 in 320, immersion for five
minutes and subsequent covering for one hour; (2) copper carbonate
2 oz. per bushel ; (3) a mixture of dehydrated copper sulphate dust
and hydrated lime (0-43 lb. to 0-57 1b.), 2 oz. per bushel. The fourth
plot was left untreated as a control.

In all the experiments the formalin gave perfect control. Copper
carbonate was effective where the bunt percentage was low, while
copper sulphate and lime was less satisfactory. Both in field and
greenhouse tests formalin appreciably retarded growth. For wheat
the percentage of germination averaged 82-78 for formalin, 93-56
for copper carbonate dust and 94-90 for copper sulphate and lime
dust, against 96-64 for the control, whilst the average percentages of
bunt in the resulting crops were 0, 0-65, 1-98 and 12-26 respectively.
For the single trial on oats the corresponding figures were 93-6,
96-6, 97-6, 95-3 and 0, 1-0, 5-6, 7-5 respectively. Additional trials
will be carried out with copper carbonate, which presents several
advantages over formalin.

Further tests on wheat were made with copper carbonate mixed

460

with lime, infusorial earth, and tale, as well as with various
combinations of copper sulphate, Bordeaux mixture, and sulphur
dust. The last-named reduced the amount of bunt to 2-5 against 15-8
in the control and deserves a further trial on grounds of economy.
In a somewhat similar series of tests in the control of smut on the
hull-less Liberty oats, which are liable to a serious reduction of
germination when treated with formalin, copper carbonate alone
gave fairly satisfactory results (1 per cent. against 7-5 in the
control) but the addition of tale, lime, or infusorial earth reduced
its effectiveness (6-3, 5-6, and 6-9 per cent. smut respectively).
Seed-o-San, chlorophol, and the ‘Gas Grain Pickler’ method did
not give very encouraging results, the last-named causing injury to
germination.

ANDERSON (P. J.) & Osmun (A. V.). An improved formaldehyde
tank for the Onion drill. Phytopath., xii, 4, pp. 161-168,
3 figs., 1923.

In this paper the authors describe in detail a tank attachment
for an onion seeding machine which will deliver formalin at
a constant and any desired rate for the control of onion smut
| Urocystis cepulae]. In all the types used at present, the rate of
delivery varies according to the head of liquid in the tank and this
has been surmounted by making the tank air-tight and placing the
air inlet at the bottom of the tank in close position to the outlet
for the liquid. The rate is regulated by the size of the hole ina
disk inserted in the outflow pipe.

Youne (H. C.). The toxic property of sulphur.—Ann. Missouri
Bot. Gard., ix, 4, pp. 403-433, 4 diag., 1922. [Ree’d, 1923. |

In this work the author has attempted to determine the exact
nature of the fungicidal property of sulphur. After a brief account
of the history of sulphur sprays and references to the work of
previous investigators, he describes a series of experiments carried
out to ascertain the degree of toxicity to Colletotrichwm gossypii,
Sclerotinia cinerea, Botrytis cinerea, Glomerella cingulata, Gloeo-
sporium venetum, Macrosporium sarcinaeforme, Phomopsis sojae,
and Actinomyces scabies, of flowers of sulphur (ordinary and finely
ground), colloidal sulphur, lime-sulphur, and the volatile products
of sulphur. The Van Tieghem cell and the hanging-drop culture —
method were employed. The culture solution was a slightly
buffered mixture containing mannite, phosphoric acid, and sodium
hydroxide.

Flowers of sulphur were found to be directly toxie only to
Sclerotinia cinerea and Phonopsis sojae. The spores of the re-
maining organisms germinated and the germ-tubes grew normally
when in direct contact with the sulphur particles. The general
fungicidal value of flowers of sulphur, if it exists, must be due
to some change in form which takes place under different con-
ditions from those obtaining in Van Tieghem cells. Within the
usual range, the hydrogen-ion concentration did not appreciably
influence the percentage of germination. Finely ground flowers of
sulphur were found to be more toxic than unground sulphur, the
range of greatest toxicity being between Py 4-2 and 5-4.

461

Colloidal sulphur exists in two forms, termed by the author
hydrophilic and hydrophobic respectively, depending on the degree
of hydration. The hydrophilic form has a high degree of hydration
and is identical with the ‘soluble colloidal sulphur’ of Raffo and
Mancini (Koll. Zeitschr., 9, pp. 58-61, 1911) and may be prepared by
adding a saturated solution of sodium thiosulphate to concentrated
sulphuric acid very slowly, repeated cooling, warming, and standing,
and finally filtering until no more insoluble sulphur comes down, the
final filtrate being the slight turbid yellowish solution which is
subsequently purified. The hydrophobic colloidal sulphur has a
very low degree of hydration and is identical with that prepared
by V. Weimarn and Molyschew (Koll. Zeitschr., 8, p. 214, 1911) and
is the ‘milk of sulphur’ formed when sulphur is precipitated.
Full details of the preparation of these substances used in the
following experiments are given.

The toxicity of the hydrophilic and hydrophobic colloidal
solutions was tested, in hanging drop cultures, omitting, however,
Glomerella cingulate and Actinomyces scabies. The hydrophilic
form proved extremely toxic, only Botrytis cinerea and Muacro-
sporium sarcinaeforme offering a slight resistance to a dilute
suspension. In stronger suspensions ‘the germination of all the
organisms was inhibited. The hydrophobic solution, however, only
exerted approximately the same slight toxic action as oround
flowers of sulphur. The influence of ‘the hydrogen-ion concentra-
tion, especially on hydrophilic colloidal sulphur, was very striking,
‘settling out’ increasing rapidly as soon as the Py value exceeded 5- 4.

Lime-sulphur is extremely alkaline and its initial efficiency as
a fungicide may be partly due to free hydroxyl ions. Tests were
made of the Py value of washings from sprayed surfaces exposed
to various drying conditions and it was found all gave a final
reaction of Py 6-4, indicating that the protracted efficiency of lime-
sulphur is not due to its causticity. The toxicity of the individual
compounds of exposed or changed lime-sulphur (precipitated
sulphur, calcium thiosulphate, calcium sulphite and calcium
sulphate) was next determined, and the lasting fungicidal value of
lime-sulphur found to be due almost entirely to the precipitated
sulphur. The toxicity of lime-sulphur was somewhat greater than
that of hydrophobic colloidal sulphur, but less than that of hydro-
philic colloidal sulphur. The hydrogen-ion concentration influenced
the toxicity in a similar manner as recorded above. A table is
given showing the germinations of the various fungi, with the
various forms of sulphur at ten different Py values.

To determine the degree of toxicity of the volatile products of
sulphur (the foregoing results having indicated that sulphur is
most toxic ina finely divided state), an experiment was arranged in
which the action of the vapours of flowers of sulphur, and of hydro-
philic and hydrophobic colloidal sulphur on Botrytis cinerea, Col-
letotrichum gossypit, and Sclerotinia cinerea was tested. The spores
were placed in drops of the slightly buffered solution without sulphur,
the sulphur suspensions being placed at the bottom of the Van
Tieghem cells. In this way the spores were separated from the
sulphur by a distance of 8 mm. The cultures were incubated at
22°C. The flowers of sulphur exercised no toxie action even on

ee

462

the sensitive S. cinerea and the hydrophobic colloidal sulphur was
only slightly toxic to B. cinerea and C. gossypiz. As in the
previous tests the hydrophilic colloidal sulphur exhibited the usual
degree of toxicity, especially at concentrations of Pu 4-0 to 5-5.
Having determined that the toxic substance is volatile it was
thought necessary to eliminate hydrogen sulphide, and sulphur
dioxide and trioxide as possible toxic factors. A saturated solution
of hydrogen sulphide did not inhibit germination and no toxicity
could be noted with sulphur dioxide, in a concentration sufficient to
kill when converted into hydrophilic colloidal sulphur by the
addition of hydrogen sulphide. Sulphuric acid inhibited growth
only in proportion to its acidity. Positive tests for sulphur dioxide
and trioxide could not be obtained in aerated sulphur suspensions
toxic to S. cinerea. These compounds, therefore, do not contribute
to the toxic properties of sulphur.

In all the above experiments, the only oxygen available was that
present in the closed rings, and an experiment was therefore con-
ducted to determine the effect of unlimited oxygen in increasing the
toxicity of flowers of sulphur and precipitated sulphur (hydrophobic
colloidal sulphur) using Petri dishes in comparison with closed
rings. The germination of S. cinerea and C. gossypii was found
to be much greater in the latter experiments, and the tests proved
conclusively that the toxic property of sulphur is due to an
oxidation product, and that finely divided sulphur is more readily
oxidized at ordinary temperatures than the ordinary sublimed
sulphur. Tests in non-air tight cells, with S. cinerea, using dry
hydrophobic sulphur and the suspension respectively, showed no
inhibition of germination with the former. Oxygen and water are
therefore necessary factors in the formation of the toxic volatile
compound of sulphur.

The results of all the above experiments indicate that hydro-
philic colloidal sulphur contains the toxic substance produced by
the ordinary forms of sulphur. Having eliminated the more
common oxides and acids of sulphur it was thought that the toxic
compound may be one of the polythionic acids. It was found that
hydrophilic colloidal sulphur not only contains such an acid but
that the method employed in the preparation of the former for
these experiments was practically identical with that employed for
pentathionie acid.

The author tested the toxicity of this substance by freeing
a hydrophilic colloidal sulphur solution from it, and it was found
that the killing power (using Botrytis cinerea and Colletotrichum
gossyptt) was directly proportional to the amount of pentathionic
acid present. The fact (ascertained by experiment) that the latter
substance is an oxidation product of sulphur at ordinary tempera-
tures, and also that it is volatile, an active absorption compound,
and that it is unstable when in acid and alkali solutions, are held
to support the view that it is the substance on which the toxicity
of sulphur depends.

The study of the practical applications of the above data is not
yet complete. A sulphur compound which will retain its fungicidal
properties regardless of climatic factors is being sought. The
material must readily yield pentathionic acid. The reaction must

J a a ———_

si

463

be kept slightly acid (Py 4-0 to 5-5) as the toxic compound is
destroyed above or below this point. The solution must be readily
oxidizable at ordinary temperatures, very adhesive, and not
injurious to foliage. Colloidal sulphur combines all these properties
when tested in the jaboratory and greenhouse, and methods for its
preparation in a form suitable for fungicidal use are being tested.
Hydrophilic colloidal sulphur appears to be adapted for use as
a spray and is not too expensive for practical purposes.

The practical application of the methods devised by various
investigators for the preparation of colloidal sulphur are briefly
discussed and a bibliography of sixty titles is appended.

RuBAN (G.). Le permanganate de potasse: agent de traitement
de maladies de la Vigne. |Permanganate of potassium: a
method for the control of Vine diseases.] Rev. de Vitic., viii,
1502, pp. 269-272, 1923.

Excellent results have been obtained in the control of vine
mildew (Oidiwm) by washing the stems in winter with a solution
of potassium permanganate (300 to 350 gm. per hl. of water).

The permanganate, which must be thoroughly dissolved, is usually
curative rather than preventive in its action, destroying the spores
of the fungus when they are actually present but not retaining its
efficacy more than a few hours. Its adhesiveness may be increased
by the addition of lime at the rate of 3 kg. per hl. of the solution. .j

In the case of varieties which cannot tolerate sulphur—e.g.
Othello—the use of the permanganate is practically indispensable. |

|

Cuan (T. A. B.). Ueber die Mycorhiza der Buche. [The mycor-
rhiza of the Beech.J|—Allg. Forst. und Jagdzit., xcix, 2,
pp. 25-31, 4 figs., 1923.

The isolation of the mycorrhizal fungus from the roots of beech
trees [see also this Review, i, p. 304] from Munich and the Tyrol is
described in considerable detail. The medium used was 1-5 per
cent. agar in a mineral nutrient solution consisting of 1 gm.
K,HPO,; 0-l1gm. CaCl,; 0-l1gm. NaCl; 0-3gm. MgSO,7H,0O;
0-005 gm. FeSO,; 1000 gm. distilled water to which 0-25 per cent.
of starch was added.

The fungus isolated was named Mycelium radicis fagi. The
mycelium was septate, greenish in colour, the longer hyphae 4 to 6
and the shorter 2 to 4 in diameter. On plum and malt agar a
luxuriant aerial mycelium was formed. In cultures three to four
weeks old irregular conidia were formed by the constriction and dis-
solution of the long and short hyphae. The addition of one per
cent. peptone to the medium resulted in the dissolution of all the
hyphae into conidia resembling those of the orchid fungus. Clamp-
connexions were absent and in transverse sections of the root the
fungus presented a sclerotial appearance.

Of the various sources of carbon tested, saccharose, mannite,

' manna, dextrose, gum tragacanth, and arabinose promoted develop-
ment; amygdalin, aesculin, cacao-butter, and lactose were inter-
mediate ; while starch, maltose, asparagin, nucleic acid, malic acid,
formic acid, and tartaric acid were unfavourable, these results
indicating the probable presence of emulsins. Growth was entirely

464

inhibited on benzoic acid and urea, and also by concentrations of
tannin exceeding 0-05 per cent.
Further investigations are in progress.

Tits (D.). Les excitants de la germination d’un champignon:
Phycomyces nitens. [The stimulants to the germination of
a fungus: Phycomyces nitens.|—Bull. Cl. Sci. Acad. Roy. de
Belgique, Sér. 5, vill, 5, pp. 219-227, 4 figs., 1922.

Before commencing his study on the stimulation of germination
of fungi preliminary tests were made by the author, using Phy-
comyces nitens, to determine the optimum temperature for germina-
tion and the development of the first sporangia of this fungus.
Each of a series of tubes containing fresh white bread and prune
juice was inoculated with a five days old sporangium and the tubes
incubated at various temperatures. One series of tubes was arti-
ficially illuminated day and night, while another similar series was
maintained in total darkness. The best culture in the illuminated
series was obtained at a temperature of approximately 22° C., the
tubes incubated at 19°, 23°, and 27° giving markedly inferior
growth. Corresponding results were obtained from the tubes kept
in the dark, a notable feature of which, however, was the larger
size of the sporangiophores.

The effect of various substances on the germination of the spores
at 22° C. was then investigated. The spores failed to germinate in
solutions ef 0-5 to 5 per cent. glucose, saccharose, lactose, and
raffinose with and without the addition of various nitrogenous
substances (asparagin, leucine, ptyaline, pepsine, and glycocol) and
tartaric acid at varying concentrations. With 1 per cent. of
peptone, however, germination was secured in less than 24 hours.
The process of germination is described and figured. The maximum
concentration of peptone compatible with germination is 30 per
cent., whilst in solutions from 0-7 to 0-9 per cent. the spores
germinated but their appearance was abnormal... The addition of
saccharose to the medium reduces the quantity of peptone neces-
sary to ensure germination ; thus in a solution of 100,000 parts of
water, 8 parts of peptone, and 700 parts of saccharose, the results
are equivalent to those obtained in a solution of 100,000 parts of
water and 700 parts of peptone.

Bacteriological peptone is composed of an aggregate of amino
acids, and is obtained by the hydrolysis of meat albumin in the
presence of tartaric acid. In the sample used the presence of
tryptophane, tyrosine, phenylaniline, and cystine was detected.

Further studies on the action of amino acids in the germination
of P. nitens are in progress.

Wermer (J. L.) & Harter (L. L.). Influence of temperature on
the pectinase production of different species of Rhizopus.—
Amer. Journ. of Botany, x, 3, pp. 127-182, 1928.

In view of the relationship found to exist between the different
species of Rhizopus with respect to the temperatures at which they
cause rots [see this Review, i, p. 433], experiments were undertaken
to ascertain the influence of temperature on pectinase production in
Rhizopus nigricans, reflerus, delemar. oryzae, nodosus, tritici,

465

maidis (all parasitic on sweet potato), microsporus, and chinensis.
The amount of the enzyme was estimated by the maceration of
disks of sweet potato in solutions from cultures or in water suspen-
sions of pulverized mycelium. A table showing the average rate
of maceration for each of the eight species at 9°, 20°, 30°, and
40° C. is given. The amount of enzyme, both that exuded into
the substratum and that retained in the mycelium, was least at the
highest temperature. The quantity of enzyme in the mycelium was
found to increase with a decrease in the temperature down to and
including 9°C. Similar results were obtained from the solution
except for a slight reduction in the quantity of enzyme produced
when the temperature was lowered from 20° to 9°C. The non-
parasitic species produced a considerable quantity of enzyme,
while the parasitic R. nigricans manufactured only a very small
amount.

A comparison was made of the relative length of time required
by the enzyme produced by the different species to macerate the
tissue of freshly dug sweet potatoes and those held in storage for
several months. The fungi were grown at 9°, 30°, and 40°C.,
maceration being carried out at the last-named temperature. It
was found that, in general, the middle lamellae of old potatoes were
dissolved in about half the time required to macerate the tissue of
new ones.

PARTRIDGE (G.). Potato inspection and certification in Canada,
1922,— Agric. Gaz. of Canada, x, 2, pp. 121-1238, 1923.

The head-quarters of the Canadian potato inspection service are
at the Central Experimental Farm, Ottawa, the service being under
the direction of the Dominion Botanist, Dr. Giissow, with the writer
in immediate charge. The work of the service, which began on a
small scale in 1915, now extends throughout the Dominion. It is
organized by provinces, a supervisor in each province being respon-
sible to head-quarters for the work of the permanent and temporary
inspectors employed by the service. British Columbia maintains a
provincial service conforming, however, to Dominion standards.

During 1922, a total of 3,283 fields, comprising 11,250 acres, was
inspected, the average amounts of disease in the fields accepted for
certification being as follows: blackleg [ Bacillus atrosepticus| 0-47
per cent., leaf roll 0-65 per cent., mosaic 1-06 per cent., and wilts
| Fusarium oxysporum or Verticillium albo-atrum | 0-14 per cent.

As a result of the experience gained during the past years,
definite and permanent field inspection standards have been decided
upon, and will take effect from next season. The standard adopted
is as follows: blackleg 3 per cent., leaf roll (including curly dwarf,
crinkle, spindling sprout, and streak) 2 per cent., and wilts 3 per
cent., provided that in no case shall a total of more than 6 per
cent. be allowed.

The following are the standards for tuber inspection: bacterial
rot [various bacteria] or wilt 2 per cent.; late blight [Phytophthora
infestans] and dry rot [Fusarium oxysporum | 3 per cent.; common
seab [Actinomyces scabies} and severe Rhizoctonia 5 per cent.;
powdery scab | Spongospora subterranea| 1 per cent.

es ee

466

Rosa (J. T., JR.). Note on an indirect effect of spraying Potatoes
with Bordeaux mixture.— Amer. Journ. of Bot., x, 3, pp. 113-
116, 2 figs., 1923. :

A spraying experiment conducted at Columbia, Missouri, during
1921 indicated that the application to Irish potatoes of Bordeaux
mixture or other preparations tending to increase the yield and
prolong the period of vegetation may, under certain conditions, be
accompanied by undesirable results.

Early Ohio potatoes were given four applications of 4-4-56
Bordeaux, with and without arsenate of lead and nicotine sulphate,
the sprayed plants remained green three weeks longer, and gave an
average yield 34-2 per cent. higher than the controls. In the
absence of early and late blight [Alternaria solani and Phyto-
phthora infestans|, these results must be ascribed to the control of
tipburn and hopperburn. The tubers from the sprayed plots,
however, consisted largely of knobby second growths, so that the
actual quantity of marketable potatoes was much less than from
the control plots, which showed second growth only to a moderate
extent. The knobby growths appeared to be produced during
periods of favourable weather, at the tips of previously formed
tubers, 4 or 5 growth zones sometimes being identified.

The writer thinks that sharp fluctuations in the soil-moisture
content, such as accompany rapidly alternating meteorological con-
ditions, may be largely responsible for the phenomenon of second
growth, especially on the Early Ohio variety. Salaman has shown
(Journ. Min. Agric., xxviii, p. 43, 1921) that the tendency to produce
second growth is not transmissible, and that knobby second growths
planted as seed pieces gave a larger yield than pieces from normal
tubers. Hence there is no reason to regard such tubers as
physiologically defective. It is hoped that further investigations
will throw light on the relation of soil-moisture variations and
other edaphic factors to tuberization.

RAMBOUSEK (F.). Ritbenschadlinge und Krankheiten im Jahre
1921. [Beet pests and diseases in the year 1921.|—Zeitschr.
fiir Zuckerind., [Prague], xlvii, 24, pp. 324-329, 1928.

The author gives an account of the diseases of [sugar] beet
occurring in Czecko-Slovakia during 1921. Root rot was reported
during the spring from a good many localities. Im many eases,
however, the disease was not due to Phoma betae but to the type
of soil on which the plants were grown. The seedlings are unable to
force their way to the surface of heavily encrusted soils without
undue pressure and consequently they gradually decay. In order
to ascertain whether a plant is affected by the physiological dis-
order or by P. betae, the constricted and decayed portion of the
hypocotyl should be examined. A black discoloration denotes
infection by the fungus and a brown discoloration the non-parasitic
injury.

Chronic root rot was reported from one district in the middle of
July, and bacteriosis and chlorosis also occurred. Scab [ Actinomyces
scabies] was reported from two localities ; it is most prevalent on
acid soils. Heart rot (Phoma betae) occurred fairly extensively.
It is frequently confused with the cavities under the heart produced

467

by intensive growth; and may best be recognized by the black dis-
coloration of the inner leaves. Rhizoctonia violacea occurred
principally on beet following clover.

BovuRneE (B. A.). Researches on the root disease of Sugar-cane.—
Dept. of Agric. Barbados, 17 pp., 5 pl., 1922. [1923.]

Root disease of sugar-cane [see this Review, i, pp. 102 and 270]
is of greater economic importance in Barbados at present than any
other fungous disease or insect pest. The present paper is the
outcome of protracted research on the possible factors governing
the incidence of the disease in that island. The author points out
the confusion existing with regard to root disease and has been
careful to limit his investigations to ‘decomposition of roots taking
place on account of the invasion of fungi’.

Numerous isolations which are described in detail were made
from typically affected canes. The first plantation to be investi-
gated yielded a species of Rhizoctonia closely resembling R. solani.
From another plantation a species of Rhizoctonia nearly allied to
fh. pallida Matz was recovered in pure culture, whilst from a third
plantation in 1921 RA. solanz was again isolated a number of times,
but in addition a species of usariuwm occurred, this being thought
to be the first record of Fusariwm sp. in connexion with the root
disease of sugar-cane. It was observed that neither Marasimius
sacchari nor Trichoderma lignoruin, both of which were repeatedly
recovered from dead cane roots, was isolated from freshly diseased
material. Further isolations showed that either R. solani or R,
pallida, with or without Fusarium sp., T. lignorwm, or M. sacchari,
was associated in every case with a dirty reddish discoloration of
the internal tissues of the basal portion of the stems.

The various fields affected by root disease were observed to show
a complete absence of the trash generally used in the covering of
young plant canes, resulting in a very high temperature of the soil.
This has been shown by Peltier (I/linois Agric. Exper. Stat. Bull.
189, 1916) to be correlated with the maximum virulence of attack
by R. solani. The age of the affected plants varied from first to
fourth ratoons, and whilst root disease is not restricted to any
specific kind of soil, in every case a period of excessive drought
preceded the first report of the disease.

The results of inoculation experiments, details of which are given,
proved conclusively that both R. solani and R. pallida are parasitic
on the sugar-cane and capable of producing the typical symptoms
of root disease. Control plants maintained under the same con-
ditions showed no signs of disease, whilst inoculation experiments
with M. sacchari and Fusarium sp. gave negative results.

The reaction of the medium between —15° and +30° Fuller’s
scale has no effect on the growth of R. solani [see also this
Review, ii, p. 419], but R. pallida develops best between + 25° and
+30° Fuller’s scale, with comparatively good growth between 5°
and 20° and fair growth between —15° and 0°. The best growth
of both fungi was obtained on Diaprepes grub agar, glucose and
glycerine peptone beef agar, sweet potato agar, and cornmeal agar.

During the examination of the basal portions of an infected stool
a typical rot of the fibro-vascular bundles resembling that described

468

by Matz as due to Plasmodiophora vascularwm {see this Review, i,
p. 314] was noticed. A histological investigation of sections of the
diseased material revealed the presence of very active, ciliate,
protozoan organisms. The numerous encysted forms of these
protozoa bore a striking resemblance to the spherical, smooth, or
coarsely granulated spores with thick, hyaline walls described by
Matz. After several days the cysts turned from hyaline to orange-
yellow or brownish. Their diameter, when mature, varied from
13-5 to 16 p, occasionally 8 to 19. As inthe case of P. vascularum
germination was never observed. The adventitious roots of the
stool in question and others from which the organism was isolated
were all infested by one or other of the root-destroying fungi.
A full description of the protozoan organism, which is stated to
grow well on potato agar, sterilized cane stem and cane juice, is
appended.

Hinp (R. R.). Toledo Cane: a mosaic-immune variety.—Sugur
Central and Planters’ News, iv, 3, pp. 105-107, and 110, 5 figs.,
1923.

Dr. E. W. Brandes has discovered that a variety of sugar-cane
growing on the estate of Sefior Toledo, Del Carmen, Pampanga
{ Luzon, Philippine Islands], is immune from mosaic disease. The
variety, in appearance and size, greatly resembles D—1135, being
erect in habit, thick in growth, and with longer internodes than
are usually found in local canes. The rind is tough, purple in
colour, and the pith yellowish; the leaves are dark green, narrow,
and quite straight. The leaf sheaths adhere tenaciously to the stalk
even when dead, forming a protective covering which may partially
explain the complete absence of attack by the maize aphis [ Aphis
maidis|. Some idea of the luxuriant growth and prolific yield of
the Toledo variety may be given by the statement that from six
stools cut for seed in December 1920 there are now seven hectares
of cane. Some stools of ratoons produced forty-two stalks, the
latter rarely exceeding 14 in. in diameter.

In view of the prevalence of mosaic disease of sugar-cane in the
Philippines, the discovery of an apparently immune variety is of
considerable interest.

WILBRINK (G.). Warmwaterbehandeling van stekken als genees-
middel tegen de serehziekte van het Suikerriet. [Hot water
treatment of setts as a remedy for the sereh disease of Sugar-
cane. |—Meded. Proefstat. Java Suikerind., 1, 15 pp., 1923. -

In July 1921 a series of experiments was eee out at Cheribon
[Java] to test the effects of hot water treatment on sugar-cane setts
affected by sereh disease. A preliminary test with healthy EK 28
setts indicated that 30 minutes’ immersion in water heated to
a temperature of 52° to 55° C. was not injurious to germination in
that particular variety. For comparative purposes a test was also
made with Black Cheribon setts suffering from gummosis. It was
found that the hot water treatment almost completely inhibited
germination in this case, so that the possibility of controlling the
latter disease on these lines appears very slight. Setts affected with
gummosis are destroyed at lower temperatures than healthy ones,

469

which may facilitate the selection of sound setts for planting, but
this has not yet been fully investigated.

The results of the experiments with Black Cheribon and White
Preanger setts affected by sereh disease may be summarized as
follows. The immersion of Black Cheribon setts in water heated
to a temperature of 52° to 55°C. for 30 minutes somewhat im-
paired germination but absolutely controlled the disease. The
general condition of the crop was excellent. Immersion at the
same temperature for 15 minutes gave slightly less satisfactory
results both as regards freedom from the disease and general
vigour. The untreated controls were nearly all diseased.

The germination of White Preanger setts was not impaired by
immersion at 50° to 55° C. for 30 minutes, but complete control was
also not obtained. Some of the setts were planted in February
1922 after 30 minutes’ immersion at 45° C. and another 30 minutes
at 50° to 52°C., with excellent results. The idea of preliminary
heating was suggested by the author’s discovery that some 15
minutes elapse before the interiors of moderately thick setts reach
the temperature of 52°. Immersion at a temperature of 48° to 50°,
even after a preliminary heating, gave less satisfactory results.
Further tests in February 1922 with the EK 28 variety confirmed
the previous results. The outcome of a few preliminary tests
indicates that the method is suitable also for the control of the root
rot fungus [? Marasmius sacchari], but not for that of stripe
disease [mosaic].

The fact that sereh disease ean be controlled by the exposure of
the affected setts to a certain temperature strongly suggests that it
is caused by a parasitic organism, the thermal death point of which
lies between 50° and 55°C. Further investigations will be
necessary to ascertain the nature of the organism involved, but in
the meantime the theory that sereh disease belongs to the ‘de-
generation’ group appears to be definitely disposed of. Mosaic and
allied diseases are known to thrive at considerably higher tempera-
tures than that which destroys the sereh organism.

On account of the possible reduction of germination it is not at
present advisable to recommend the hot water treatment on a large
scale. It is believed, however, that a method can be devised
whereby the injury to germination is eliminated. In the mean-
time the practice of the hot water treatment on a small scale,
particularly in experimental stations and the lke, can safely be
recommended.

Lee (H. A.). Sereh disease of Sugar-cane in Singapore.—P/iyto-
path., xiii, 3, p. 145, 1923.

In 1922 whilst at Singapore Botanic Gardens the writer found
sugar-cane affected with the typical symptoms of the sereh disease
of Java. The canes had been imported from Java. He calls
attention to the risk of sereh, Fiji disease, downy mildew [Sclero-
) <i and cane smut [Ustilago sacchari| diseases being trans-

mitted on canes imported from oriental countries into the western
hemisphere where these diseases are unknown or at least not
general,

470

MU Luer (K. O.). Ueber die Beziehungen von Moniliopsis ader-
holdi zu Rhizoctonia solani. [On the relations between
Moniliopsis aderholdi and Rhizoctonia solani.|—Arb. Biol.
Reichsanst. fiir Land- und Forstwirtsch., xi, 4, pp. 321-325,
1 fig., 2 diag., 1923.

Several investigators, references to whose work are given, have
endeavoured to throw light on the systematic position of the so-
called ‘propagation fungus’ (‘ Vermehrungspilz’), which causes
considerable damage in seed-beds. The fungus, which has been
referred to a variety of genera, including JMortierella, Botrytis, and
Sclerotinia, was later named Moniliopsis aderholdi by Ruhland
(Arb. Biol. Reichsanst. fiir Land- und Forstwirtsch., 6, pp. 71-76,
1908), and more recently it has been identified by Duggar (Ann.
Missouri Bot. Gard., iii, p. 1, 1916) with Rhizoctonia solani or its
basidial stage Corticitum vagum var. solani.

The results of comparative cultural experiments, the technique
of which is fully described, with strains of Moniliopsis aderholdi
(identical with authentic cuitures of this fungus) from cyclamen
leaves and of A. soluni from potato roots revealed a number of
differences between the two fungi. The maximum, minimum, and
optimum temperatures for the growth of the mycelium of WW.
aderholdi were 31-8° to 35°, 14°, and 29° [C.] respectively, the
corresponding temperatures for mycelial growth of FR. solani being
slightly over 30°, 7°, and 25° [C.]. Morphological differences were
also noticed. The mycelial texture of MW. aderholdi, especially at
the higher temperatures, was finer than that of R. solani, the
average diameters of the hyphae being 7 u and 8-3 p respectively.

In order to test the influence of osmotic concentration and the
chemical reaction of the medium on the development of the
mycelia, varying concentrations of the Van ’t Hoff salt mixture
(100 Mol NaCl, 2 Mol CaCl,, 2-2 Mol KCl, and 7-8 Mol MgCl,) were
added to the potato leaf agar. The cultures were incubated at
a temperature of 26.5° [C.]. The initial concentration p was 4
per cent. NaCl and the corresponding mixtures of the other salts.
Marked differences in the reaction of the two fungi were perceptible.
Whereas the Rhizoctonia cultures developed normally at and
beyond the concentration /2, those of Moniliopsis made only
feeble and irregular growth at the same concentration. At p the
development of Moniliopsis was virtually inhibited. In general,
the mycelium of Moniliopsis was denser than that of Rhizoctonia.
At the higher concentrations Moniliopsis showed a much stronger
tendency to develop involution forms than Rhizoctonia. At p/4
abnormal formation of the hyphae of M. aderholdi were frequent,
and at 3p/4 there was hardly a normally shaped hypha to be seen.
In R. solani, on the other hand, only isolated irregularities of hyphae
formation were observed, even at the highest concentrations.

Fragments of MW. aderholdi grew in liquid cultures at acid con-
centrations which inhibited the mycelial growth of R. solanz. The
optimum acid concentration for the development of M. aderholdi
was p/2, and for that of R. soluni p/1. The hyphae of R. soland in
liquid cultures gradually wove themselves into a firm, membranous,
mycelial weft; while those of I. aderholdi developed in coils and
finally formed a more or less spherical mycelium.

471

Inoculation experiments with J/. aderholdi on thirty potato
tubers previously disinfected with formalin resulted in the forma-
tion, close to the point of inoculation, of isolated, dark brown,
sclerotial bodies, resembling those described by Ruhland as ‘pseudo-
sclerotia’. No injury to the young shoots was observed, and the
hyphal network on the roots and underground portions of the
stem, which is typical of Rhizoctonia infection, was entirely absent.
Parallel tests with Rhizoctonia cultures gave positive results both
on tubers and shoots, all the well-known symptoms of infection
being present.

It is apparent from the above investigations that J. aderholdz
cannot be regarded as identical with R. soluni, and that, for the
present, the systematic position of the former remains obscure.
The fact that M. aderholdi can only flourish at temperatures
between 14° and 35° C. explains its incidence at medium and high
temperatures in greenhouses and seed-beds.

MULLER (K. O.). Weber die Beziehungen zwischen Rhizoctonia
solani Kihn und Hypochnus solani Prill. et Del. [On the
relations between Rhizoctonia solani Kiihn and Hypochinus
solani Prill. & Del.|—Arb. Biol. Reichanst. fiir Land. und
Forstwirtsch., x1, 4, pp. 326-330, 1 fig., 1923.

After a brief review of the work of Rolfs and other investigators
on the connexion between Rhizoctonia solani and Hypochivus solani
Prill. et Del. (Cortictwm vagum B. & C.), the author describes his
own experiments in the same field.

In September 1922 a number of flower-pots were half filled with
sterilized soil and in each two tubers, previously disinfected with
formalin, were planted on the surface of the soil. Fragments of
potato stems attacked by Hypochnus mycelium were attached to
the under side of the glass panes covering the pots, so that the
spores from these fragments fell on to the tubers. After 36 hours
the tubers were covered with sterile soil and placed in the green-
house. By December, 60 per cent. of the seedlings from the in-
oculated tubers showed the typical symptoms of infection by
Rhizoctonia. The underground portions of the young shoots were
covered with brown hyphae and a partial disintegration and brown
discoloration of the epidermis was observed. The uninoculated
control tubers remained healthy. Hypochnus spores therefore are
capable of producing the typical Rhizoctonia disease, and further
experiments showed that mycelium developed from Hypochnus
spores (which was identical in all respects with that obtained from
Rhizoctonia) also behaved similarly.

The results of comparative cultural experiments also point to the
identity of the two fungi. For all the Hypochnus strains the
maximum temperature for growth was about 30° {C.], the minimum
between 5° and 7-3°, and the optimum about 23° [C.]. These
figures agree closely with the temperature relations of RA. solani
[see preceding abstract]. There were, however, discrepancies in
some of the strains which seem to indicate that the species H. solani
includes a variety of biological forms. Thus two strains grew less
rapidly than the others, their mycelia being correspondingly sparse.
The virulence of the strains also varied considerably. Apart from

472

negligible divergences, the reaction of H. solani to the osmotic con-
centration and to the acidity or alkalinity of the medium approxi-
mated to that of R. solani [see preceding’ abstract].

In order to produce the fructifications of Rhizoctonia, four tubers
artificially inoculated with Khizoctonia were placed in each of
seven flower-pots in the greenhouse. At the time of flowering
four of the resulting plants were covered with the typical Hypochnus
mycelium at the base of the stem. Similar tests were conducted
in the field, 150 tubers being inoculated with Rhizoctonia and
a further 150 sefving as controls. It was impossible entirely to
preclude natural infection by H. soluni, however, the control plants
giving 17 per cent. infection whilst those artificially inoculated
gave 38. ;

The basidial stage of Rhizoctonia was also obtained in pure
culture in Erlenmeyer flasks filled with 50 cc. of a solution con-
taining 1 per cent. Witte peptone and 0-5 per cent. potato starch.
Within 17 days the mycelium was sufficiently developed to be
transferred, after washing, to tubes containing filter paper saturated
with water, maintained at a temperature of 20° to 21°[C.]. The
mycelium developed aerial hyphae, and on the fifth day basidia
were detected in two of the cultures. The measurements of the
basidia averaged 9-5 by 5-7 » and thus agreed with those obtained
by Saceardo. The sterigmata appear to be somewhat smaller than
those figured in Engler’s ‘ Natiirlichen Pflanzenfamilien’ (i, 1, p. 115,
1900). Such a minor discrepancy, however, is probably due to the
action of certain external factors on the cultures, and do not
invalidate the conclusions mentioned above.

Matns (E. B.). Evidence of the seed carriage of the Euphorbia
rusts, Uromyces proeminens and U. dictosperma.—Proc.
Indiana Acad. Sci., 1921, pp. 137-139, 1922. [Ree’d 1923.]

The author describes his experiments relating to the seed trans-
mission of Uromyces proeminens, occurring on Huphorbia dentata
and #. »reslii, in the vicinity of Lafayette, Indiana, and U. dicto-
sperma occurring on FL. arkansana and other species in the
western States. He also presents additional facts relating to the
identity of the systemic aecidia on the latter hosts with U. dicto-
sperma and to the production of uredospores in the life-cycle of
this fungus.

In the autumn of 1920 seed was collected from plants of Z.
dentata heavily rusted with the teleutospores of U. proeminens.
The seed was sown on 22nd January [1921] and the first symptoms
of infection were observed on Ist March, when pycnidia appeared
on one capsule of one plant. Subsequently other plants developed
pycnidia or aecidia, or both. A brief discussion of the symptoms on
each affected plant is given.

Seed from plants of £. arkansana heavily infested with teleuto-
spores of U. dictosperma was collected in July 1920 and planted in
the following August. On 12th November one branch of one plant
became infected and died. After this all the plants remained
healthy till March [1921] when eleven of the forty-two plants
showed infection by aecidia or pycnidia, or both. Later uredo-
and teleutospores appeared on most of the plants, presumably from

473

aecidial infection. The branches infected with aecidia died without
setting seed and the plants finally showed only teleutospores.

Aecidia from the above-described material were sown on healthy
plants and produced uredospores, which were, however, soon re-
placed by the characteristic teleutospores of U. dictosperma. It is
evident therefore that the systemic aecidia found on £. arkansana
represent the aecidial stage of U. dictosperma. The subsequent
production by these aecida of uredo- and teleutospores denotes that
U. dictosperm is a full-cycled, autoecious species.

The above evidence is considered sufficient to prove that these
two rusts are seed borne. The manner of their dissemination will
form the subject of further investigations.

Petcu (T.). Black rot of tea.—Trop. Agric., lx, 2, pp. 89-90,
1923.

During the last year a comparative examination has been made
of thread blights on various plants from Java, India, Ceylon, the
West Indies, and West Africa. An examination of the Java and
Sumatra specimens proved conclusively that the species of Corti-
cium causing black rot of tea in Ceylon is not C. theae. The latter
is a true thread blight, forming a definite white cord running along
the stem of the host plant. On the other hand, the mycelium of each
of the Ceylon black rot fungi runs along the stem in a very thin,
hyaline film which is invisible to the naked eye unless in the act
of producing a fructification.

Recent investigations indicate that there are at least two species
of Corticiwm causing black rot in Ceylon. One of these occurs on
tea, Oxzyanthus tubiflorus, Calophyllum burmanni, and Hemidesmus
indicus, and will probably be found to be a general parasite on
jungle shrubs. The other occurs on coca (Erythrorylon coca), but
owing to the difficulty of obtaining mature fructifications it is not
easy to distinguish one species from another.

Black rot of tea was originally discovered in the low country,
but has since been found at an elevation of nearly 6,000 ft. Its
distribution, therefore, is probably general.

Percu (T.). Cercosporella leaf disease.— Trop. Agric., Ix, 2,
pp- 87-89, 1 pl., 1923.

The symptoms and distribution of the leaf disease of tea, caused
by Cercosporella theue, are described. The essential features of the
disease have already been reported |see this Review, i, p. 331, and
ii, p. 294]. A plate shows affected leaves and a typical spore of the
parasite.

Wotr (F. A.). Wildfire of Tobacco,— North Carolina Agric. Exper.
Stat. Bull. 246, 26 pp., 7 figs., 1922.

In North Carolina wildfire of tobacco, caused by Bucteriwm
tabacum, makes its first appearance in the seed-beds during the
last week of April or beginning of May. A wet rot stage not pre-
viously described by the present writer occurs on the smallest
plants, the leaves of which are often completely rotted, whereas in
other cases the infected tissues wither and fall away. A water-
soaked zone divides the healthy from the diseased tissues. The

47 4

bud leaves of affected plants are pale, erect, and slow to develop,
and the plants may perish in the seed-bed or not survive trans-
plantation. The areas affected are usually on the lowest and
dampest portions of the beds.

Observations in North Carolina, extending over a considerable
period, show that wildfire invariably originates in the seed-bed.
This confirms the results obtained by other investigators in Virginia,
Massachusetts, and Connecticut.

The remainder of the Bulletin deals with the effects of the disease,
the results of experimental work, the factors governing the trans-
mission of wildfire, and appropriate measures of control, notes on
which have already been published from other sources [see also this
Review, i, pp. 93, 94, and 376, andi, p. 37).

TispaALE(W. B.). Tobacco diseases in Gadsden County in 1922.—
Florida Agric. Exper. Stat. Bull. 166, pp. 77-118, 1922.

The following tobacco diseases occurring in Gadsden County
[Florida] are described and figured, appropriate measures of control
being recommended in each case.

Mosaic was not serious in 1922, as it appeared very late and
affected chiefly the sucker leaves. Infected horse nettle [Solanum
carolinense| and ground cherry {Physalis|] plants are common in
the tobacco fields of Gadsden County, and are believed to promote
the spread of the disease. In both these plants the symptoms of
the disease are much less conspicuous than in tobacco, and one
species of ground cherry is said to act as a carrier of mosaic without
itself showing any signs of infection. Mosaic may spread for a
distance of several hundred feet among the weeds, and during the
past season it was observed that mosaic was transmitted from plant
to plant by labourers poisoning for budworm. Mosaic plants should
be pulled out and the hands thoroughly washed before touching
healthy plants. The eradication of weeds and covering the plant
beds with cloth to prevent the transmission of the disease by plant
lice and flea beetles are also recommended.

Wildfire, caused by Bacterium tabacum, was reported from
Florida in 1921, but the diagnosis was regarded as somewhat un-
certain. In 1922, however, the disease appeared in three two-acre
fields, the source of infection being traced to two plant beds, one of
which was covered with second-hand cloth from Connecticut. In
all probability the germs were carried on this material. A descrip-
tion of this disease, together with suitable measures of control, has
already been published [see this Review, ii, p. 37]. Granville wilt,
caused by Bacterium solanacearum, appears to be decreasing in
prevalence in: Florida, and the attack in 1922 was extremely mild.
The hope of developing strains of tobacco resistant to this disease
has not been realized, but a method of shallow cultivation may be
devised, which would reduce root injury and thereby lessen infection.
All possible measures to localize the outbreak should be taken.

Leaf spot, due to Phyllostictau nicotianae, appears to be limited in
distribution and of minor importance. No definite control mea-
sures can be recommended until more is known of the life-history
of the causal organism, but observations made in 1922 suggest that

475

the injury may be reduced by sowing the seed thinner, or thinning
the stand on the poorer spots of soil.

Root rot, caused by Thielavia basicola, was widespread in 1922;
growers report that during average years the plants finally out-
grow the disease and produce fairly good yields, the crop, however,
being two to four weeks late in maturing. Attempts are in pro-
gress to develop strains of tobacco resistant to root rot, the most
promising of which are Connecticut Round Tip and (according to
Valleau and Kinney) White Burley [see this Review, ii, p. 37.]

Frog-eye or ‘specking’, caused by Cercospora nicotianue, was
very prevalent in 1922. Very little damage was sustained by the
crop in fields where the leaves could be primed early, but wher-
ever this process was delayed by rain considerable losses were
caused by the disease. Vigorous, rapidly growing plants appear
resistant, the fungus attacking mainly those weakened by unfavour-
able weather and soil conditions; in 1922 a fortnight’s rain in June
appeared to be the predisposing factor. The following suggestions
are made for control: (1) root rot predisposes to frog-eye and hence
varieties resistant to it should be selected where root rot is preva-
lent; (2) deep cultivation late in the season should be avoided, as
this tends to check the growth and thus causes premature ripening
of the leaves.

‘Black shank’, which made its first appearance in the United
States in 1915 in Decatur County, Georgia, is rapidly gaining
a foothold in Gadsden County, where it was the most serious disease
of tobacco in 1922. Big Cuba was the most resistant variety and
Connecticut Round Tip and White Burley the most susceptible.
Conspicuous symptoms of the disease, which only attacks tobacco,
are damping-off of seedlings, a dry black rot of the basal portions
of the stalks of older plants, and a sudden wilting of the leaves.
The roots of such plants are partially or entirely decayed, with
a brown or black discoloration, but plants with apparently healthy
roots may show the typical lesions on the stalks. As a rule these
appear on the stalk at soil level and advance in both directions.
Mycelial hyphae are usually present in streaks of brown, woody
tissue; the pith within the diseased area is dry and brown and
usually split into plate-like disks.

The disease may also affect the leaves, stalk, petioles, or leaf-
blade during damp, cloudy weather, producing large brown blotches
varying from one to three inches in diameter. On the Big Cuba
variety these blotches are circular and marked with concentric
bands of different shades of brown, whilst those on Connecticut
Round Tip and Wisconsin No. 1207 are dark brown and at first
have the consistency of wet rot. In this condition the diseased
plants resemble Irish potato plants suffering from late blight
| Phytophthora infestans |. Conidiophores and conidia of the causal
organism have been observed in small numbers in the leaf lesions
during cloudy weather, accompanied in lesions a few days old by
species of Fusarvwm. When priming takes place during damp
weather as much as 20 per cent. of the leaves from infected fields
may rapidly develop greenish blotches, mottled with brown, after
being hung in the barn. No further development has been observed
to occur in the packing house.

eta, ~

a

ee kT

476

The specific organism has been isolated from typical ‘black
shank’ plants and proved by inoculation experiments to be highly
pathogenic to healthy tobacco plants. The morphology of this
fungus corresponds closely with that of Phytophthora nicotianae
de Haan, with which it is in all probability identical. The conidia
are mostly ovoid and apiculate, 25 to 33 yw in diameter, olivaceous,
with a granular content. They begin to germinate in distilled
water in about 15 minutes, producing ten to twenty zoospores, oval
or bean-shaped, about 6-5 » in diameter, and then after 15 minutes
they cease activity, enlarge, and apparently disintegrate.

A difference in resistance between individual plants and varieties
appears to exist. Until more information regarding the disease is
available, its spread should as far as possible be localized by
appropriate measures which are given in detail.

VaALLEAU (W. D.). An important period in the life history of two
bacterial organisms causing leaf-spots on Tobacco.— Phyto-
path., xiii, 3, pp. 140-144, 1 fig., 1923.

Angular leaf spot [Bacterium angulatum] and wildfire [ Bact.
tabacum] of tobacco have been shown by Fromme to be transmitted
by the seed [see this Review i, p. 94, and ii, p. 244]. There is some
evidence, however, that the organism of the former disease at least
may live in the soil some considerable time and as a few infected
plants in the field can start infection of large plantings, treatment is
desired which will remove all traces of the disease in the seed-bed.

By adding sulphur at the rate of 500 Ib., 1,000 lb., and 2,000 Ib.,
per acre to trial plots in a greenhouse, the author controlled the
disease completely although infected seed was used, whereas in
untreated plots numerous infections occurred where the tips of the
cotyledons curled back and touched the soil. The treatment,
however, was disastrous to the young plants, which were reduced
severely in numbers, and it cannot be recommended for practice.
The work, however, is considered to indicate that soil infection
occurs first and leaf infection follows and that complete control of
the disease may be obtained by suitable applications of disinfectants
to the soil.

Departmental Activities: Botany.—Journ. Dept. Agric. S. Africa,
vi, 3, pp. 202-2038, 1923.

Nicotiana rustica, which until recently was free from parasitic
diseases in §. Africa, except the disease known as brown spot,
caused by Macrosporium longipes, has now been reported from
Vereeniging to be attacked by the root parasite Striga oroban-
choides. In all probability this plant’s life-cycle is similar to that
of the related broom rape | Orobanche| which is a common parasite
on tobacco and other plants in many parts of the world, and its
spread may, therefore, be checked by persistent uprooting and
destruction before the seed matures.

The tobacco-growing districts of the Transvaal, owing no doubt
to the exceptional rainfall during the month of March of this year,
have suffered severely from disease. Wildfire [see this Review, 11,
p- 37] has been prominent and widespread, and one farmer from
Groot Marico reported the ruin of his entire crop of 60,000 plants

ee

477

from this cause. Angular leaf spot [ Bact. angulatum] is now also
mentioned as occurring in the Transvaal as well as brown spot,
mildew, mosaic, and frenching, which all occurred to a greater or
less extent.

Crayton (KE. E.). The relation of soil moisture to the Fusarium
wilt of the Tomato.— Amer. Journ. of Botany, x, 3, pp. 133-
146, 3 pl., 1923.

Investigations were conducted at the University of Wisconsin
during 1919 and 1920 to ascertain the relation between varying
amounts of soil moisture and the development of tomato wilt
(Fusarium lycopersici). The technique of the experiments and of
the methods, used in the control of soil moisture is described in con-
siderable detail. ;

Tomato plants were grown in crocks of sterilized soil inoculated
with a spore suspension of F’. lycopersict. The soil in the crocks
was held at moisture contents ranging from 13 to 35 per cent., the
latter representing complete saturation, and for the experiments
the temperatures were finally raised to the optimum for the disease

(about 28°C.). The results of a series of experiments showed that |

plants growing very rapidly under optimum moisture conditions for
vegetative growth are most susceptible to wilt. The plants grown
in soil with a low moisture content (13 to 19 per cent.) were very
resistant to the disease, a moisture shortage which checked growth
bringing about a proportional check in symptoms of the disease.
The plants grown in saturated soil were immune from the disease.

Rapidly growing plants in inoculated soil held at a temperature
below 20°C. remained healthy, but when they were brought into
a temperature favouring the disease (25° to 30° C.), they were soon
attacked by wilt, unless the soil was allowed to dry out, in which
case the appearance of the disease was retarded. Conversely, plants
growing in soil with a low moisture content lost their resistance
to the disease if a rapid, succulent growth was induced by the
addition of sufficient water to keep the soil moist. Plants growing
in the saturated soil also developed the disease as soon as the moisture
content was lowered.

With regard to the resistance of plants grown under dry soil
conditions, it was found that even when these plants showed no
signs of disease they were frequently discoloured in the vascular
region and if incubated long enough were killed by wilt. As the
fungus produces the disease very slowly, the host is regarded as
being resistant under these conditions.

The reason for the relative immunity from wilt of plants grown
in saturated soil was also investigated. From microchemical
analyses it was found that the nitrogen relations in the saturation
plants differed markedly from those of normal ones. Resistance
appeared to be correlated with the absence of nitrate nitrogen. To
test this theory plants were grown in sand cultures to which
nutrient solutions were added. Part of the plants received a com-
plete nutrient solution and the remainder a solution minus nitrate.
The tissues of the plants grown in the latter solution were not
infected while those which had received the complete nutrient
solution developed the disease.

478

JARDINE (N. K.) Inspection for plant pests and diseases.—T'op.
Agric., 1x, 2, pp. 90-92, 4 pl., 1923.

The Department of Agriculture, Ceylon, has divided its Plant
Pests and Diseases Inspection Branch into two divisions, a central
one at Peradeniya and a southern one at Avisawella. The work of
the divisions is educational, advisory, and official. Special attention
is given to the gardens of small native cultivators, who are gradu-
ally being educated to realize the importance of pest control as
a means to the production of better crops. Advice is given as to the
adoption of remedial measures and, if necessary, the regulations for
the control of the shot-hole borer of tea and other pests are enforced.

TRAvVERSO (G. B.) WL’organizzazione dei Servizi fitopatologici in
Italia. [The organization of the phytopathological services in
Italy.|—Reprinted from Atti XVI Congr. naz. Unione delle
Cattedre ambulanti di Agricoltura italiane, 12 pp., 1928.

A short account is given of the legislation leading up to the
present organization of the phytopathological services in Italy,
which is based on the Act of 26th June 1913 for the preven-
tion and control of plant diseases, the regulations governing its
application passing into law in 1916, The general objects in view
are as follows: (1) the study of plant diseases; (2) the control of
production and of trade in vegetable products with a view to
preventing the introduction of exotic parasites and to cireumscrib-
ing certain dangerous diseases which are still confined to specified
areas ; (3) the carrying out officially of control measures; and (4) the
organizing and directing of agricultural societies with the object of
combating certain plant diseases.

Apart from the administrative section which forms a special
department of the general administration of agriculture under the
ministry and is aided by a consultant commission (the Phylloxera
Commission formed in 1879 modified by the Acts of 1911 and 1915),
the machinery of the above services consists of: (1) experimental
institutes; (2) regional phytopathological observatories or stations ;
(3) special phytopathological delegates; and (4) plant disease in-
spectors. On the first devolves the scientific study of diseases and
the experimental application of remedies. The observatories have
to collect phytopathological material, carry out statistical enquiries
and study the behaviour of plant diseases in their own districts.
They also issue phytopathological certificates for the dispatch of
plants and seeds inland or abroad. The special delegates’ duty is
to inspect horticultural establishments, nurseries, gardens, markets,
&e., to ascertain the health of vegetable products destined for
marketing, and to report to their immediate superiors, the directors
of the observatories. They have, moreover, to supervise the in-
spection at the ports and at certain frontier stations of all imported
plant material, and function as judicial police in cases of contra-
vention of existing regulations, the reports concerning these being
also drawn up by them. The inspectors are in charge of campaigns
on a large scale against plant diseases carried out by, or with the
aid of, the State but under the immediate direction of the regional
observatories. They are also made use of in propaganda work.

The author states, that although theoretically the organization,

479

as outlined is perfect, its working in practice leaves much to be
desired. Lack of Government support, financial insecurity, in-
difference on the part of agriculturists, unsuitable buildings, absence
of adequate experiment grounds, and insufficient remuneration of
workers, are responsible for the fact that the experimental institu-
tions, namely, the Cryptogamic Laboratory of Pavia, the Station of
Agricultural Entomology at Florence, the Station of Plant Patho-
logy at Rome, and the Laboratory of Agricultural Entomology
attached to the College of Portici, have failed to maintain their
old-established fame as leaders in scientific research on the diseases
and pests of plants. These central phytopathological institutions
should be placed in a position to undertake serious research and
experiment. The technical and scientific personnel for the various
services should receive its training there; this is at present obliga-
tory for the inspectors but should be extended to include the special
delegates also. The foundation of new experiment stations should
not In any way imply that the existing ones are allowed to decay.

Of the twenty-three regional observatories formed in 1917 only
about a fourth are independent, the others being branches of various
experiment stations, laboratories attached to higher or special
schools, or other agricultural institutes, where phytopathological
interests are secondary and where this additional and responsible
work is undertaken by the local staff without adequate remunera-
tion. The author, while not denying the advantage of the proximity
of other experimental or teaching institutes, thinks that the regional
observatories ought to have their own properly trained personnel.
He is also of opinion that their cost should not fall entirely on
the State, as is the case at present, but that the major portion
should be borne by the various agricultural and commercial interests
concerned.

The special delegates, of whom there are about one hundred, were
appointed provisionally from amongst directors and assistants at
experiment stations, botanical and research institutes, &e. The
composition of the existing staff is regarded as too heterogeneous
and the author advocates the appointment of persons who have had
more opportunities of getting into touch with farmers and horti-
culturists. The forestry inspectors and also the staffs of the
ambulant agricultural chairs and of anti-Phyllozera societies, are
thought most suitable. They should not be specialists in either
mycology or entomology, but a practical knowledge of the diseases
covered by legislation and of the legislation itself, of the most
recent research work connected with control measures, and of the
manner of taking satisfactory samples for scientific study, is essen-
tial, and may be imparted by means of courses to be organized by
the Union of Ambulant Agricultural Chairs. The provincial
branches of this body might perhaps organize local phytopatho-
logical services, but always in co-operation with the regional
observatories. Such an arrangement would make for greater
uniformity and efficiency.

The plant disease inspectors should be increased in number in
proportion to the increase of the regional observatories on which
they are dependent. It is also necessary that the State should fix
their remuneration at a level to attract young students of promise

480

in agricultural or natural science subjects, likely to profit by the
two years training prescribed by law for these posts.

Under the existing legislation the formation of communal, inter-
communal, or provincial organizations for the control of certain
plant diseases on the lines of the anti-Phylloxera societies, is
optional. The author would like to see this made compulsory in
certain cases.

From an international standpoint an efficient organization of
the phytopathological service is of the greatest importance. It is
equally important in the interests of the country itself. Export
business depends on it, as is shown by the certificates required in the
case of certain important commodities, which are not admitted into
other countries without these guarantees. An efficient service may
be expected to effect a progressive reduction in the losses caused by
the diseases and pests of plants as has been the case in regard to
human and animal diseases. The text of a resolution embodying
the reforms outlined in the present paper 1s appended.

A decree to make provision for the protection and preservation
of plantations (No. 18 of 1922), Zanzibar, 14th August, 1922.

The Plantations Preservation Decree, 1922, provides for the
destruction of clove, lime, orange or other trees or shrubs infected
by deleterious fungi of any description, or by the parasites Loran-
thus var. and Cassytha var. Similar provision has been made for
the destruction of coco-nut trees infested with insect pests. The
occupier of land whereon clove or coco-nut trees are grown is
required to clean and weed such land at least once every year to
the satisfaction of the Director of Agriculture or his representatives.
Any inspector may, at his discretion, order the destruction of any
tree or heaps of decaying matter attacked by or likely to become
a breeding place for any parasite, and, in the event of such order
being disregarded by the occupier, may himself take the necessary
measures for its execution at the occupier’s expense. For the
purposes of this decree ‘occupier’ shall mean the person entitled to
the immediate profit of any land, and by a recent amendment
(Decree No. 7 of 1923) the term has been further extended to
apply also to persons licensed to gather crops and to tenants,
irrespective of the period of the licence and of the tenancy.

Amendment No. 2 to regulations governing the importation of
Potatoes into the United States (revised).— U.S. Dept. Agric.
Fed. Hort. Board, January 1923.

As from Ist February 1923, the regulations governing the
importation into the United States of potatoes from Canada and
Bermuda [see this Review, 1, p. 408] have been amended to read as
follows :—‘ Potatoes grown in the Dominion of Canada and Bermuda
may be imported into the United States without permit, when ac-
companied by a certificate issued by a duly authorized officer of
the country concerned, indicating the district or locality where
grown and apparent freedom from injurious potato diseases and
insect pests. Such importations shall be subject to such inspection
on arrival as may be required by the United States Department of
Agriculture.’

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

ae eLIiED MY COLOGY

Von. i NOVEMBER 1923

HumpuHrey (C. J.). Diseases of ornamental and forest trees.—
Ann. Rept. Wisconsin State Hort. Soc., lii, pp. 92-99, 3 figs.,
1922.

In the case of forest and ornamental trees, leaf-inhabiting fungi
are not of such importance as they are in fruit trees. A conspicuous
representative is the tar spot of maple (Rhytisma acerinwm) which
may be controlled by the burning of the fallen leaves in autumn in
order to prevent infection by ascospores in the spring. Chestnut
bark disease [Hndothia parasitica], which has practically destroyed
the native chestnut stands north of North Carolina, can be combated
only by the breeding of resistant varieties.

Wisconsin, however, is more vitally affected by the serious white
elm disease, caused by Sphaeropsis ulmicola. The most striking
symptom of the disease is the sudden death of certain smaller
branches scattered throughout the crown, due to girdling. Below
the girdle water-sprouts very often develop. Over the attacked
areas the smooth bark becomes somewhat sunken and loses the
normal healthy green appearance. From these girdled regions the
fungus grows into adjacent healthy tissues so that the whole crown
may in time become involved. Every possible effort should be
made to eradicate this epidemic and destructive disease. Infected
limbs should be excised and burnt, while ample watering and
fertilization also assist in the recovery of diseased trees. Infected
seedlings should be destroyed.

Near Madison Armillaria mellea is most commonly found on
scarlet and black oaks, and sometimes on white and bur oaks. In
the fruit-growing regions it occurs on various stone fruits, especially
the cherry, while on the Pacific coast it is reported to cause
a serious disease of small fruits. The main line of control should
be the prevention of the spread of the infection. The isolation of

L

er? mr

482

infected areas by trenching is useful only in the case of definitely
localized infection.

For the treatment of wounds shellac is recommended for small
wounds and for larger ones a 50:50 mixture of coal-tar creosote
and asphaltum. In the case of such delicate trees as the peach,
cherry, plum, magnolia, and tulip a 25:75 mixture of coal-tar
creosote and asphaltum may be substituted for the above. The cut
bark and adjoining wood should be painted with shellac before the
creosote mixture is applied.

The author concludes with a brief discussion on the care of trees
in the public parks and highways and urges the necessity of muni-
cipal control for the prevention of injury and disease.

KONIG. Ueber Rotfaulebestande und deren Behandlung. {Stands
infected with red rot and their treatment. |—Tharandter forstl.
Jahrb., \xxiv, 2, pp. 63-74, 1923.

During his administration of the Lossnitz [Saxcny] crown lands,
the author observed numerous cases of red rot of fir trees cultivated,
for the most part, on what was formerly arable land. Resin was
exuded from the trunks of affected trees and the fructifications of
Trametes radiciperda |Fomes annosus| were frequently observed.
The entire root system of fallen trees was often found to be
decayed, the weaker strands being severed. As a rule the base of
the trunk was only fit for firewood. The affected trees sometimes
formed a circle round groups of completely healthy firs, which
became infected one by one. The stiff clay soil of the Lossnitz
forests also favoured the disease by preventing the penetration of
the roots, which were frequently severed in one or more places,
thereby affording easy access to the spores of the fungus.

The presence of smoke gas is another frequent source of trouble,
the acids impeding the decomposition of the humus in the soil.
The local practice of planting the seedlings in groups, instead of
singly, also increased the danger of infection by weakening the
individual development of the trees. The use of fir trees on the
borders of plantations, where they are exposed to the full force of
the wind, is another fault of cultivation. They should be replaced
on the north, east, and west by shade trees, if the soil is deep
enough, or by larches or white pines in shallow soil. Gaps in the
interior of the stand should be filled with hornbeam, beech, or ash
trees.

Boycr (J. 8.). The deterioration of felled western Yellow Pine
on insect-control projects.—U.S. Dept. Agric. Bull. 1140,
7 pp., 1928.

The losses from decay in western yellow pine (Pinus ponderosa),
felled and barked in order to control insect epidemics, in the
Klamath Lake region of southern Oregon are relatively slight (13
to 18 per cent.) during the first year. In the second year, however,
they are so heavy (63 to 76 per cent.) that the cut trees must be
regarded as lost if they cannot be utilized within twelve months.
Among the fungi causing decay were Polyporus anceps, Lenzites
saeprarin, and Fomes pinicola.

483

ScHELLENBERG (H. C.). Die Empfanglichkeit der Ribesarten fir
den Rost der Weymouthkiefer. (The susceptibility of Ribes
species to White Pine blister rust.|—Schweiz. Zeitschr. fiir
Forstwesen, \xxiv, 1-2, pp. 25-50, 1923.

Since the writer first detected blister rust (Cronartiwm ribicola)
on Pinus cembra in the Engadine, he has collected data on the
comparative susceptibility to the disease of the various species of
Ribes. Taking 10 to represent the highest degree of susceptibility
and 0 as immunity, the species may be classified as follows :—Ribes
nigrum, 10; R. petraewm, 9-10; R. alpinum, 7-9; R. uva crispa,
6-8; R. grossularia, 2-8; R. awrewm, 5-7; R. rubrum, 2-4.

R. nigrum appears to exhibit no varietal differences in the
degree of attack, while R. grossuluria, formerly supposed to be
immune, varies considerably in susceptibility. Of two bushes in
the author’s garden one bearing pink berries was regularly and
severely infected, while on a yellow variety the attacks were ex-
tremely rare and negligible in extent. Other similar instances
have also been observed. The author's investigations do not
confirm Klebahn’s theory that the stock in grafted bushes exerts an
influence on the susceptibility of the scion.

R. rubrum appears to be exceedingly resistant to the disease
even in the immediate vicinity of heavily infected black currants.
This statement applies primarily to the Dutch red currant, which is
extensively cultivated in Switzerland. The Versailles and the
white and striped varieties are also resistant, but slightly less so
than the Dutch.

As regards the ornamental currant species, both R. sanguineum
and R. gordonianwm are very susceptible, R. awreuwm, which is
always used as a stock for espalier currants or gooseberries, is less
susceptible than A. sanguinewm and R. gordonianum but more so
than R. rubrum.

The susceptibility of the wild species, R. petraeum and R.
alpinum is of no great importance, since they occur only in the
Alpine regions where the pine is not cultivated. Much more
serious is the liability to the disease of R. uvw crispa, which is
constantly found in localities where the white pine is grown on
a large scale, and which must undoubtedly be regarded as the
natural intermediate host in cases where the blister rust occurs on
white pines at a distance from cultivated Ribes.

In view of the impossibility of eradicating the wild currant from
the forests in which it has once gained a foothold, the cultivation
of the white pine in its neighbourhood cannot be recommended.

Horson (J. W.). Blister rust—a menace to prosperity.— Univ. of
Washington Forest Club Quarterly, i, 2, pp. 18-25, 3 figs.,
1922.

White pine blister rust (Cronartiwm ribicola), the symptoms, life-
history, and distribution of which are described, has been definitely
located in four different parts of Washington. An account is given
of the legislative measures formulated at the White Pine Blister
Rust Conference in December 1921, and an appeal made for general
co-operation to prevent the further spread of the disease in the
States of Washington, Oregon, California, Idaho, and Montana,

484

It is estimated that there are a billion feet of white pine in the
commercial areas of north-eastern Washington and 600,000,000
feet in Oregon.

Weir (J. R.). The genus Polystictus and decay of living trees.—
Phytopath., xiii, 4, pp. 184-186, 1923.

In this paper eleven species of Polystictus (P. abietinus, P.
biformis, P. cinnabarinus, P. conchifer, P. floridanus, P. hirsutus,
P. lacteus, P. pergamenus, P. pinsitus, P. versicolor, P. zonatus)
are listed as causing decay of trees. Notes regarding the parasitic
action of each species are given, usually showing that the decay
makes slow progress in otherwise healthy trees. The rots are usually
white or yellowish or of a slight reddish tinge in the case of
P. cinnabarinus, but are not specially differentiated. These fungi
are primarily scavengers of the forest, destroying timber débris, but
may become important in the decay of useful material left too long
in the woods.

MALAQUIN (A.). La maladie des Ormes. [The disease of Elms. ]—
Renaissance agric., iv, pp. 91-94, 1923.

This disease of elms, now reported from the neighbourhood of
Lille, is evidently the same as that already described in Holland
and Picardy [see this Review, i, p. 334, and i, p. 431]. The author
believes it to be due to the attacks of Scolytus beetles, but states
that it has also been attributed to the injurious effects of gas and to
the drought of 1921.

PETERS. Die Krauselkrankheit der Riiben. [The curl disease of
Beets. |—Deutsche landw. Presse, |, 13, p. 117, 3 figs., 1923.

Sugar and fodder beets, mangolds, and other cultivated varieties
of Beta vulgaris are liable to occasional attacks of downy mildew
(Peronospora schachtii). The first symptom of the disease is usually
a marked retardation of the growth of the heart in early summer.
The heart in such cases consists of small, discoloured, very crumpled
leaves with short petioles, encircled by fully developed leaves with
petioles of the normal length. The young heart leaves are com-
pletely diseased, the older ones remaining healthy at the tip. The
under side of the diseased leaves is covered with the whitish, subse-
quently grey, fructifications of the fungus. The dissemination of
the spores (the average dimensions of which are 24 by 204) is
presumably effected by the wind, possibly also by insects. The
incubation period seems to be very short; in any case, continuous
new infections have been observed during the growing season in
cool, damp weather. ‘The disease is rapidly arrested, however, even
by a brief spell of dry, warm weather, and the decayed heart leaves
are then replaced by small, narrow ones. In this stage of the
disease the affected plants resemble those suffering from heart rot
[attributed by some to Phoma betae, by others believed to be
a physiological disorder] except for the absence of the dry patches
of decay on the sides of the root. Early infections generally cause
some reduction in yield and in the sugar content of the beet owing
to the temporary disturbance of metabolism ; on the other hand, the
frequent cases of reinfection in the autumn are of little practical

485

significance. Tests carried out at the Uckermark Sugar Factory at
Strasburg showed a reduction in the sugar content of diseased beets
of only 0-2 to 0-4 per cent.

Giumann has shown that the species of Peronospora are usually
very highly specialized in their parasitism, rarely affecting more
than one host plant. It is therefore very improbable that the
mildew of beet can be transmitted from or to other members of the
Chenopodiaceae. The conidia of the fungus remain viable only for
a very brief period, and the formation of resting spores, in Germany
at any rate, is very uncommon. The mycelium of P. schachtii,
however, can overwinter in the tissues of infected beet roots and
infect the new shoots. When beet for seed bearing is planted out
the diseased shoots from the infected roots can be recognized by
their stunted growth, curled or crumpled leaves, and copious spore
production. The common practice of locating the seed-beds next to
tields planted with seed bearers (‘ stecklings’) favours the spread of
the disease and should be discontinued. All the infected portions
of seedlings and seed bearers should be removed and buried. At
harvest it is advisable to discard all suspected plants from use as
seed bearers. The fields in which the latter are planted should be
situated in such a position that the prevailing winds do not pass
over them before reaching the seed-beds. By the adoption of these
simple measures complete control of the disease is stated to be
ensured.

Takimoro (K.). On the vitality of Cercospora beticola.—Ann.

Phytopath. Soc. Japan, i, 5, pp. 43-44, 1923. [In Japanese,
with English summary. |

Spores of Cercospora beticola kept in a dry condition at the
laboratory remained viable for 16 months, while those on the seeds
were capable of germination until the sowing season, at the end of
April, of the following year. The spores on diseased leaves kept in
cellars were not able to germinate at the beginning of May, but
sclerotial bodies or mycelia in the tissues were viable throughout
the winter. The results of field experiments showed that sclerotial
bodies and mycelia were frequently viable after the spores had lost
their germinating power. In the laboratory the spores of diseased
leaves mixed with wet soil died in three to four weeks.

GARDNER (M. W.) & Kenprick (J. B.). Bacterial spot of Cowpea.—
Science, N. S., lvii, 1470, p. 275, 1923.

Since 1919 a destructive bacterial disease of the cowpea (Vigna
sinensis) has been noted in Indiana, leaves, stems, and pods being
affected. On the leaves the symptoms consist of irregularly
circular spots, 1 to 3 mm. in diameter, with maroon edges and buff
centres. The young lesions are greasy and water soaked, On the
pods the spots are also irregularly circular, 1 to 8 mm. in diameter,
and maroon in colour, often with a depressed centre and water
soaked border. Early infection may cause a constriction of the
pod and stunting of the distal portion, and the seeds under the pod
lesions may be stunted, shrivelled, or discoloured. Dark red,
elliptical to linear, sunken lesions are formed on the petioles and

486

stems. In addition to lesions on cotyledons, first leaves, hypocotyls,
and epicotyls, localized vascular infection and partial wilting may
occur among seedlings grown from diseased seed.

Numerous isolations and successful inoculations proved the
disease to be due to an apparently undescribed bacterium, the
diagnosis of which is as follows: Bactertwm vignae n. sp.
Cylindrical rods, rounded at ends, solitary or in pairs; individual
rods, 1-5 to 2 by 0-54; motile by 1 to 5 polar flagella at one or
both poles; aerobic; no spores or capsules. Gram negative ;
staining readily with gentian violet. Superficial colonies on potato
agar round, smooth, shining, raised, pulvinate, or umbonate, finely
granular, often showing a concentric pattern, greyish-white in
reflected light, slightly greenish fluorescent in transmitted light.
Gelatine rapidly liquetied; casein digested and no acid produced
in milk; nitrates not reduced; no gas with various carbohydrates
and no acid except for small amount with dextrose and saccharose ;
starch not hydrolized. Growth and greenish pigment formation in
Fermi’s and Uschinsky’s solutions; no growth in Cohn’s solution ;
slow liquefaction of blood serum and Loeftiler’s blood serum.
Growth inhibited by 5 per cent. sodium chloride. Growth in broth
at +12 and —15 and at Py, 4-8. Greenish pigment formation in
alkaline broth. Thermal death point 50° C.; killed by one hour's
exposure to sunlight, and slowly killed by freezing in water.
Rapidly killed by desiccation on glass but very resistant to
desiccation on cowpea seeds. Group number 211.2232033.

The disease is seed borne and can probably be controlled by the
use of seed from healthy pods.

Harter (L. L.), Laurrrzen (J. L), & Weimer (J. L.). Mottle-
necrosis of Sweet Potatoes.—Piiytopath., xiii, 3, pp. 145-146,
1 fig., 1923.

This disease is characterized by brown, irregularly formed and
sometimes completely isolated patches of dead tissue occurring
throughout the sweet potato. In mild cases there is no external
symptom, but in advanced stages dead areas occur at the surface of
the tuber.

The disease has been observed at digging time and is reported
from various parts of the United States. So far no causal
organism has been isolated, and sometimes the spots are free from
mycelium. The authors are continuing their investigations on the
disease.

STELL (F.). A fungus disease of Cabbages.— bull. Dept. Agric.
Trinidad and Tobago, xx, 2-4, p. 116, 1922.

The disease known as cabbage yellows, due to a species of
Fusarium |F. conglutinans], has recently been reported from the
San Juan district of Trinidad. The author briefly describes the
symptoms and life-history of this disease and states that efforts are
being made to introduce resistant varieties from the United States,
ue Wisconsin variety being under trial at St. Clair Experiment

tation.

487

Gram (E.) & Rostrup (SoFIE). Oversigt over Sygdomme hos
Landbrugets og Havebrugets Kulturplanteri1922. (Survey
of the diseases of cultivated agriculturai and _ horticultural
plants in 1922.|—Tidsskr. for Planteavl, xxiv, 2, pp.-236-307,
2 figs., 1923. [English summary. ]

The period under review (1st October 1921, to 30th September
1922) was characterized in Denmark by a dry, sunny autumn with
several heavy storms, a cold and dry period in January and February,
a late spring, and a cool, moist summer. The fungous diseases are
classified under the following headings, many other records being
given besides those enumerated below.

CEREALS. Serious attacks of stripe disease of barley (Pleosporu
graminec) occurred in various localities, especially on the susceptible
Karl and Prentice varieties. Leaf spot disease of barley (P. teres)
was very severe on Tystofte Prentice. Mildew (EZrysiphe graminis)
attacked late-sown barley on damp soil and in the vicinity of
winter barley. Severe attacks of covered smut of barley (Ustilago
hordez) on the Abed and Tystofte Prentice varieties were reported.
Wheat sown at the end of September also suffered from mildew
while that sown a month later was free from the disease. Bunt of
wheat (Tilletia caries) is notably decreasing in prevalence, partly
as a result of seed disinfection. Loose smut of oats (U. avenae) was
much in evidence, and there are some indications that it is corre-
lated with insufficient fertilization. Flag smut of rye (Urocystis
occulta) was prevalent on the Petkus, Bretagne, and Borris varieties.
The aecidial stage of black rust of wheat (Puccinia graminis) was
found on barberry bushes in several localities, including Mgen’s
Klint [an island off the south-west coast of Zealand] where the
cultivation of the shrub is permitted. It is regarded as urgently
necessary to extend the barberry eradication regulations to this
island. Foot rot of wheat and barley (Fusariwm, Leptosphaeria,
and Ophiobolus spp.) was specially severe in fields previously under
barley or beets and mildest on ground which had lain fallow for
some time.

LEGUMINOSAE. Ascochyta pisi completely destroyed the pea crops
in a number of gardens, and Sclerotinia sclerotiorwm also occurred
with great severity during the damp late summer.

Root crops. Mosaic and downy mildew (Peronospora schachtii)
resulted in severe damage to the beet crops; it is believed that
insects and implements may be concerned in the transmission of
the former disease. Phoma betae and Pythiwm de Baryanum were
frequently found in non-calcareous or very compact soils. A severe
wilt disease occurring in conjunction with deep sowing was reported
from the north of Denmark. The Elvetham and Eckendorfer beet
varieties were severely infected by Hypochnus [Corticiwm] solani.

CrucIFERAE. Club-root (Plasmodiophora brassicae) occurred
extensively on numerous varieties of cabbage, turnips, and mustard.
The disease was frequently associated with non-calcareous or cold
soils, and there were fresh instances of the transmission of infection
through refuse. Dry rot (Phoma napobrassicae), which had been
in abeyance since 1914, occurred on well-limed clay soil.

Porarors. Mosaic and leaf roll occurred with unprecedented

488

severity in the hot, dry summer of 1921, and in 1922 the propor-
tion of healthy fields was alarmingly low. The Magnum Bonum,
Up-to-date, and Juli varieties were most susceptible. The absence
of any organized scheme for the investigation of these diseases in
Denmark is very regrettable. Blackleg (Krwinia [the new name
given to various species of the genus Bacillus at the suggestion of
the Society of American Bacteriologists] phytophthora) {Bacillus
utrosepticus| was prevalent and severe in many parts of Jutland.
Various other diseases of minor importance were recorded.

FoppDER crops. The usual diseases were reported without any
particulars of special interest.

Fruit. On the whole, the damage caused by fungous diseases to
apples and pears was not extensive. Raspberries were badly
attacked by Didymelia applanata on excessively nitrogenous soils
in Fiinen. Tomatoes were attacked by Ascochyta lycopersici [| Didy-
mella lycopersict], which also appears to prefer nitrogenous soils.
Cladosporium fulvum attacked the Fillbasket, Denmark, Comet,
Kondine Red, Tuckswood, and Queen Mary varieties.

CUCURBITACEAE. Cercospora melonis attacked the Tottenham
variety of cucumber very early and severely. Cladosporium
cucumerinum and Macrosporiwm melophthorum [mentioned as
distinct fungi] were also prevalent.

ONIONS AND LEEKS. Peronospora schleideni caused severe damage
to leeks and shallots.

VEGETABLES. Mildew of spinach (Peronospora effusa) was very
severe On spring-sown plants and was observed as early as March
on the Victoria variety under glass. Bremia lactucae was preva-
lent on outdoor salads at Lyngby in August. Glomerella linde-
muthianum occurred with great severity on wax and French beans
in August and September.

TREES, SHRUBS, AND ORNAMENTAL PLANTS. Among the diseases
recorded were Macrosporium caudatum on zinnias [Zinnia sp.}.
Graphiola phoenicis and Exosporium preisii on imported Phoenix
palms | Phoenix sp.], Pestalozzia quepini on camellias [Camellia sp.],
and Bacterium twmefuciens on marguerites.

In the section of the report devoted to diseases presumably of
physiological origin, mention is made of the leaf edge disease of
red Dutch and red Spanish currants, yellow apricots, and Cox’s
Orange apples. The disease was aggravated by the application of
saltpetre. Bright speck disease [see this Review, i, p. 421, and ii,
p- 403] was recorded on oats, barley, rye, Panser wheat (in conjunction
with frost injury), beets, potatoes, and carrots. Indoor tomatoes
were affected by a similar disease, presumably in consequence of
plentiful applications of lime, bonemeal, and organic manure.

A brief account is given of the results of experiments in the
control of plant diseases carried out during the year. Apples and
climbing roses were injured by the application of 2 per cent.
Burgundy mixture with the addition of 0-5 gm, Schweinfurt green
per litre. The sale of this mixture is illegal on account of the free
arsenious acid formed in it. Moltke pears suffered from scalding
after spraying with 0-5 percent. formalin. At the Lyngby Experi-
ment Station 2 per cent. Bordeaux mixture injured Bismarck
apples and several pear varieties, whereas lime-sulphur 1 in 35

489

produced no ill effects. In North Jutland the application of a
tobacco extract, containing only a small proportion of nicotine,
resulted in complete defoliation [crop not specified] owing to the
presence of free ammonia in the compound.

[BewLEy (W. F.)]. Mycological Report.—LHighth Ann. Rept.
Cheshunt Exper. and Res. Stat. Hertfordshire, 1922, pp. 34-45,
1923.

Among the diseases not hitherto reported but observed during
the year were the following: bronzing of roses, due to an unknown
cause, dropsy or oedema of tomatoes and ivyleaved geraniums (of
physiological origin), bulb rot of narcissus (due to Botrytis sp.),
and mosaic diseases of ash, black nightshade (Solanum nigrum),
Petunia, potato, tobacco, and passion flower [ Passiflora].

The main object of research during the period under review
was mosaic disease of the tomato and cucumber, but the new tomato
root rot reported last year [see this Review, i, p. 372] and stem rot
were also investigated.

The new tomato root disease was first observed in 1919, and in
1921 it was frequently found on roots of wilted plants. The
results of local observations indicate that the disease is more serious
than was at first assumed, most soils on which tomatoes have been
grown for any length of time being infected.

The normal development of affected plants is checked, the lowest
leaves turn yellow and die prematurely, and any new growth
which may be formed is weak and pale in colour. In advanced
stages the stem becomes hollow and yellow, a dark brown discolora-
tion, usually about a quarter of an inch wide, sometimes appearing
at one side of the base of the stem. ‘ Hollow stem’ disease is often
associated with this disease at the roots. In the final stages
all the leaves wither and the plant dies. The distinctive feature
of the disease is the presence of innumerable minute, globular,
black sclerotia, both within the larger wood vessels in the pith
cavity and on the outside of the wood. Those within the tissues
are irregular in shape and rarely develop setae. Though generally
confined to the roots, the sclerotia may also, in severe cases, be
found on the base of the stem and the lower portion of the aerial
parts. The infected wood is usually of a darker shade of brown
than that attacked by Verticillium albo-atrum or Fusariwm
lycopersict.

The causal organism, Sclerotiwm setosum Bewley & Shearn, was
readily isolated. The fungal filaments produced comparatively few
conidia on short branches, and numerous black sclerotia approxi-
mately 1/200th of an inch in diameter and covered with black setae.

The fungus enters the plant through the roots and spreads
rapidly upwards, sometimes reaching 32 inches above the ground
level. Healthy plants grown in sterilized soil, copiously inoculated
with sclerotia from a pure culture showed signs of root rot within
six weeks and in three months the typical symptoms developed,
the controls remaining healthy in each case. The fungus was
readily re-isolated from the decayed roots. The results of inocula-
tions above ground were negative, but both green and red tomato
fruits were rapidly rotted by the fungus. The above results

L2

r> @*

490

indicate that the disease is contracted in the soil and that infection
of the aerial portion rarely, if ever, occurs.

The investigation of control measures is still in progress. Avail-
able data point to the probable introduction of the disease in straw
manure. An examination of tomato roots at the Experiment
Station has shown that where no stable manure has been applied
for five years the plants are healthy, while those which receive
annual dressings of stable manure are badly diseased. .

Stem rot of tomatoes, caused by a species of Botrytis, may be
recognized by the grey or greyish-brown, slightly depressed, smooth
patches extending up the stem and girdling it near the leaf or truss
bases. In moist atmospheres the diseased portion becomes covered
with a luxuriant grey mould composed of the spore-bearing fila-
ments of the fungus. Infection takes place through jagged, badly
pruned, half-dead leaf bases or leaves, and broken tissues, and
the fungus attacks the cortex, vascular tissues, and pith, producing
a brown discoloration. Spreading rapidly through the stem, the
fungus causes the death of all parts above the lesion. Spore pro-
duction takes place abundantly on leaves and fruits, which thus
become a source of infection to the stems.

Preventive control measures should be based on a careful regula-
tion of the ventilation, circulation, and humidity of the air, and on
correct methods of pruning and defoliation. Severely infected
plants can only be saved by the excision of the diseased portion of
the stem and the sterilization of the wound with a strong solution
of liver of sulphur or copper sulphate. In some cases the applica-
tion of a paste of liver of sulphur to the outside of the lesion may
suffice. Spraying with a 2 per cent. solution of calcium bisul-
phite is recommended for the destruction of the spores.

Mosaic disease of the tomato, the symptoms of which are
described in some detail, is rapidly assuming considerable economic
importance. Five main types of symptoms are distinguished, the
first consisting of a simple mottling of the foliage without any
distortion; the second type resembles the first, but the spots are
indistinct in outline and deep yellow in colour (probably similar to
the Aucuba mosaic of potatoes); the third type is characterized by
a distortion of leaf margins with no mottling; in the fourth type
the leaf surface is blistered and the margins distorted; and in the
fifth type the lamina is severely reduced, resulting in the formation
of tendril-like leaves. The evidence available at present goes to
show that all these types are different manifestations of the same
disease. Besides the mottling or blistering of the leaves, cohesion
and twisting of the various parts of the flowers and sterility of the
anthers are common symptoms of mosaic disease, but mottling of
the fruits is uncommon in Great Britain. A mottling of tomato
leaves also occurs as the result of unsuitable soil conditions, but
this form of chlorosis differs materially from mosaic in the degree
of infectiousness of the plant juices.

The results of inoculation tests on young Kondine Red tomato
plants (a) with raw unfiltered juice and (b) with filtered juice
showed that in the latter case infectivity, though present, is con-
siderably reduced by filtration, The plants inoculated with un-
filtered juice all became infected in a fortnight. Of the ten

491

varieties tested Fillbasket was the most susceptible. In another
experiment three out of forty Ailsa Craig plants inoculated with
infected juice showed no signs of disease after two months. The
juice of these three plants was then inoculated into ten healthy
plants with positive results in every case, thus indicating that
a tomato plant may occasionally be infected without showing
any external symptoms of disease. Such a plant is termed a
‘ carrier ’.

Further tests indicated that the disease is readily transmissible
by means of infected juice carried on the fingers and by the pruning
knife. Aphids and white flies were transferred to healthy plants
after feeding on diseased ones and transmitted the infection in
every case. It was observed that low temperatures, by retarding
the rate of growth, prevented the development of the typical
symptoms found in rapidly growing plants at high temperatures.
In the early part of the year there was a tendency towards
blistering and distortion without mottling of the leaves, while
the latter symptom was common at the higher midsummer
temperatures.

The results of a large number of pot experiments showed that,
with the exception of rather heavy feeding with a well-balanced
fertilizer, none of the manurial treatments tested had any effect
on the progress of the disease. This line of investigation is being
continued.

It has been shown by cross-inoculation experiments that mosaic
disease of tomato is readily transmissible to Petunia, tobacco,
bittersweet (Solanum dulcamara), and black nightshade, and with
difficulty to the potato, while it is also possible to cross-inoculate
any of these from the other. Mosaic disease of cucumber has not
been transmitted experimentally to any of the above plants,

Two types of cucumber mosaic have been observed in Great
Britain, one resembling the Aucuba type, characterized by localized
yellow patches, and the other marked by mottling and blistering of
the leaves and stunting of the plants. Little damage is caused by
the former type, but the latter frequently results in a considerable
reduction of the crop. The observations on the effect of environ-
mental conditions given above under tomato are applicable also to
the cucumber. Butcher’s Disease Resister is a very resistant
variety.

No alternative hosts for cucumber mosaic have been discovered
in Great Britain, and it must therefore be assumed that infection is
transmitted by the seed, Control measures consist chiefly in the
elimination of possible centres of infection on the lines suggested
by the experimental work on tomato mosaic.

Annual Report of the Director, Wisconsin Agricultural Experi-
ment Station 1921-1922, 121 pp., 53 figs., 1923.

Among the items of phytopathological interest not already
separately noticed in this Review, the following may be mentioned.
The prevalence of stripe disease (Helminthosporium gramineum)
in the Wisconsin barley fields necessitated experiments carried out,
by Johnson and Holden to discover appropriate measures of
control. In 1921 the seed of several plots was treated with formalin,

492.

and then by roguing out any infected plants before any discharging
lesions occurred, apparently disease-free seed «was obtained.
The latter was sown in 1922 and yielded a healthy crop with no
trace of disease. The entire removal of infection was also accom-
plished by seed treatment with formalin, combined with planting at
a period unfavourable to the development of the disease.

The season was favourable for the development of apple scab
[Venturia inaequalis], experiments in the control of which were
conducted by Keitt and Jones at Madison and Sturgeon Bay. The
most satisfactory spray schedule consisted of lime-sulphur 1 in 40
(with powdered arsenate of lead, 1 lb. per 50 galls.) applied on the
following dates: (1) 12th-18th May (pre-pink) ; (2) 18th-20th May
(pink) ; (3) 29th May-—Ist June (calyx) ; (4) 8th-14th July; and (5)
5th-llth August. In most of the tests, the results from dry lime-
sulphur 4 in 50 were similar to those obtained with liquid lime-
sulphur 1 in 40. Bordeaux mixture 4-4—50 gave adequate control
but seriously russeted the fruit. The addition of glue and gelatine
as adhesives to lime-sulphur somewhat lessened the efficacy of the
latter, whilst calcium caseinate added to lime-sulphur and Bordeaux
mixture respectively, improved slightly the effect of these sprays.
Trials to substitute dusting for certain liquid applications gave
conflicting results, the success of the treatment apparently de-
pending on the relation between the time of application and
meteorological conditions. On the whole, three liquid lime-sulphur
sprays followed by two sulphur dustings gave as good control as
the five-spray lime-sulphur schedule.

The same workers carried out a series of experiments in the
control of cherry leaf spot |Coccomyces hiemalis|. As in former
years, excellent results were obtained by three applications of
Bordeaux mixture 3—-3-—50, (1) just after the fall of the petals, (2) a
fortnight later, and (3) just after harvest.. Similar schedules of
Bordeaux mixture 2-2-50, lime-sulphur 1 in 40, and dry lime-
sulphur 4-50 failed to control the disease adequately. The addition
of gelatine, glue, or calcium caseinate to Bordeaux mixture and
lime-sulphur did not materially increase the adhesiveness of these
sprays.

P The investigations of the possible relation between the pigment,
volatile oils, or associated substances in the onion and resistance to
smudge (Colletotrichum circinans) were continued. From the
chemical analysis the onion pigments appear to contain (1) a yellow
non-glucoside, (2) one or more yellow glucosides, (3) a red non-
glucoside, and (4) one or more red glucosides. A yellow glucoside
or a mixture of glucosides has been crystallized from both the red
and yellow onions, but so far has not been entirely purified. In
the ease of the yellow onions this mixture was found to be toxic to
the fungus. These results open up an interesting field in the
problem of the immunity of yellow onions and the susceptibility of
white onions respectively to the disease.

Crown gall (Bacterium tumefaciens) of raspberries has for some
years past been responsible for very heavy losses to Wisconsin
growers, and experiments have therefore been carried out. by
A. J. Riker to ascertain the exact relation between the organism
and its hosts. Inoculation experiments on the tomato showed that

493

wounds are necessary for infection. When needle punctures were
made for inoculations the release of liquid caused the formation of
water-soaked areas round the wounds. As the galls developed they
were found to coincide closely in outline with the water-soaked
regions. Expressed tomato sap was found to exert a positive
attraction on the bacteria: the latter are thought to migrate
through the water-soaked tissue and produce galls at points
removed from the site of inoculation.

The results of further tests by Jones in the control of anthracnose
[Gloeosporium venetum| of black raspberries showed that two
applications of lime-sulphur alone controlled the disease sufficiently
for commercial purposes, but that better results were obtained if
glue, gelatine, casein, lime, or saponin were added to the spray as
an adhesive. In general, Bordeaux mixture, either alone or with
an adhesive, was slightly less satisfactory than lime-sulphur. A
third application of Bordeaux or lime-sulphur about a week after
blossoming reduced the amount of disease but caused severe foliage
injury.

ARNAUD (G.). Biologie des ‘tumeurs marbrées’ de la Luzerne.
The biology of ‘ marbled galls’ of Lucerne. |—Comptes rendus
Acad. d’ Agric. de France, ix, 18, pp. 494-497, 1923.

Since 1916, when the ‘marbled gall’ [Urophlyctis alfalfae]
disease of lucerne was first recorded in France, the writer has
continued his observations on the development of the galls and the
immunity of other plants from the disease.

Various plants were sown in August 1916, the seed being mixed
with fragments of lucerne galls. Lucerne was the only plant
infected, and the disease has persisted in the plots since that date.
The dissemination of the disease appears to be slow, since it has not
yet spread to a plot of lucerne situated only about ten yards from
the experimental plot.

As a rule the galls appear on the surface of the soil in the spring,
persist throughout the year and die in the following spring. In
the dry season of 1921 the disease did not appear at all, but was
observed anew in 1922. Drought, therefore, appears to arrest the
progress of the disease. The development of the galls of plants
pulled up for examination and replanted was definitely checked and
the hosts recovered their original vigour. On one occasion an
attempt was made to control the disease by covering the soil with
a layer of earth 5 cm. in depth. The following year, however, the
galls reappeared at the original level. They were lighter in colour
and had formed small roots on the surface.

So far the damage caused to the French lucerne crops by the
marbled gall disease has been inconsiderable.

LevIn (1.) & Levine (M.). The action of buried tubes of radium
emanation on neoplasias in plants.—Jowrn. Cancer Res., vii,
pp. 163-170, 1 pl., 1922 [1923].

The clinical results of the insertion of buried capillary glass tubes
containing radium emanation into animal tumours appeared to be
of such importance that it was imperative to investigate biologically
the mechanism of the action of this method of radium therapy

494.

upon tumours in plants. The writers have previously shown
(Proc. Soc. Exper. Biol. § Med., xv, p. 24, 1917) that the main
immediate action of X-rays on crown gall [ Bacteriwm tumefaciens |
in plants consists, not in a direct destruction of the cells, but in the
arrest of their proliferating power. The death of the cells follows
as a result of the ageing of the individual tumour cell.

In the present investigations capillary tubes 3 mm. long and
0-25 mm. in diameter containing radium emanation were introduced
into artificially induced club-roots [Plasmodiophora brassicae] on
cabbage and kohlrabi, and crown galls on the geranium, and
left buried in the tissues from one to fifteen days. Empty tubes
were similarly inserted in controls. The irradiated and non-
irradiated tissues were then fixed and sectioned. These experi-
ments showed that in normal adult tissue the only perceptible
consequence of the insertion of a radium emanation tube is
the complete destruction of tissue in the immediate vicinity.
The insertion of radium emanation tubes into the crown gall
tissue, however, is followed by an inhibition of the proliferation
of the tumour, evidenced by its reduced size as compared
with controls. The soft beta rays affect mainly the tissues in
the immediate vicinity of the tubes, and in this region the cells
collapse radially, forming a cushion of cellulose round each tube.
The hard gamma rays penetrate beyond the cushion region, the
cells becoming devoid of both nucleus and cytoplasm, and although
no apparent morphological changes in the tumour cells may take
place, the proliferating power is inhibited and the increase in
size stopped. ‘The role of the cellulose cushion in plants, in walling
off the necrotic area around the radium emanation tubes and
filtering off the soft beta rays, appears to correspond with that
played by the connective tissue stroma in animal tumours. In
club-root tissue the degenerated cells immediately adjoming the
so-called cellulose cushion do not seem to contain Plasmodiophora
brassicae, which, however, is present in the cells at a distance
farther from the capillary tube.

Levin (I.) & Levine (M.). The role of neoplasia in parasitic
diseases of plants.—Journ. Cuncer Res., vii, pp. 171-178,
1 pl, 1922. [1923].

In a previous investigation (Journ. Cancer Res., v, p. 243, 1920)
on the malignancy of the crown gall (Bacteriwm tumefaciens) and
its analogy to animal cancer, the writers have demonstrated that
the gall does not develop through the specific neoplastic ‘ gall
producing’ properties of the bacterium. The present paper reports
further studies on the cause and mechanism of the formation of
neoplasia in plants after their invasion by parasites.

After discussing the mechanism of gall formation in leafy crown
gall [see this Review, ii, p. 896] and on Ficus elastica. [see this
Review, i, p. 54] the writers describe their studies on the club-root
of cabbage (Plusmodiophora brassicae) and on potato wart (Synchy-
trium [endobioticum)).

Inoculations of young cabbage plants with an infusion of old
club-roots in water were successful in producing infections, and
suitable portions of the resulting hypertrophies or hyperplasias

495

were fixed and sectioned. Club-root is a plant tumour similar to
crown gall in its derivation, mechanism of formation, and effect on
the host plant. The most striking phenomenon observed in a study
of club-root is the fact that the large groups of cells containing
the parasite are always surrounded by layers of small young cells
which do not contain the parasite. Kunkel (Journ. Agr. Res. xiv,
p. 548, 1918) thinks that this is due to the growth stimulus
travelling in advance of infection or that the uninfected cells are
immune to the parasite. The author is of the opinion that these
young undifferentiated cells are not only immune to the parasite
but present a reactive protective barrier against further inroads
of the latter (although this does not exclude the possibility of the
parasites ultimately breaking through the barrier).

Examination of prepared slides of potatoes affected by wart
disease showed substantially the same relationship between the
parasite, the normal adult tissue of the host plant, and the reactive
neoplastic tissue, as in crown gall and club-root.

In discussing these results, the authors state that neoplasia in
parasitic diseases of plants, unlike the neoplasia in animal cancer,
always represents a protective action of the plant organism against
invasion of the parasite. It has a period of progressive prolifera-
tion of undifferentiated cells, which are frequently transformed
into adult differentiated tissue, regression and death occurring’
before the destruction of the host, the gall thus behaving more like
reactive neoplasia in an animal than animal cancer. Neoplasia in
plants never represents a malignant tumour in the true meaning of
the term in animal pathology. The points under consideration in
these investigations make it evident that the study of neoplasia in
plants should become an integral part of all phases of cancer
research, etiological or therapeutical.

Tazpor (R. J.) & Bunttina (R. H.). On a disease of Cocoa and
Coffee fruits caused by a fungus hitherto undescribed.— Ani.
of Bot., xxxvii, 145, pp. 153-157, 3 figs., 1923.

Liberian coffee cultivated in the Gold Coast Colony is attacked
by a fungus which produces a dark purplish-brown discoloration,
especially of young berries, which eventually shrivel and harden.
The discoloured area Jater becomes covered with a white or pinkish-
brown mealy incrustation formed by the conidia of the fungus. In
- wet seasons the whole crop may be endangered by the attacks of
the fungus, which is also responsible for a disease of cacao fruits.
Cross inoculations from coffee to cacao and vice versa gave
typical symptoms of the disease, the fungus being re-isolated in
both cases.

In natural infections of cacao the symptoms of the disease—
locally known as mealy pod [see this Review, ii, p. 203|—resemble
those caused by Phytophthora faberi. The discoloured area at the
point of infection rapidly extends until, under suitable conditions
of humidity, the whole pod is involved, the white, later pinkish-
brown, mealy conidia form dense encrusted masses, and the pericarp
of the fruit becomes decomposed.

The results of inoculation experiments, while not conclusively
proving the parasitic character of the fungus, indicate that the

496

latter develops more readily on wounded: or moribund fruits than
on healthy ones. It has never been found on the vegetative parts
of its hosts. The effects of the disease are particularly serious on
young pods in which the protective sclerotic tissues have not yet
been formed, as the fungus is able to penetrate to the seeds.

The fungus produces in the host tissues a non-septate mycelium
of rather coarse hyphae, which spreads rapidly through the inter-
cellular spaces. Narrower branches arise from the intercellular
hyphae and penetrate the walls of the cells, which are destroyed
and their contents discoloured. The conidiophores are very
variable in form, some consisting merely of upright hyphae
terminating in a single conidium, while the more complex types
bear terminal vesicles to which one or more whorls of pedicellate
conidia or lateral fertile branches are attached. The conidia are
spherical and markedly echinulate with an average diameter of
35 pw, borne on pedicels up to 30 in length. On cacao the conidia
occur on the inner surface of the ovary wall, the mucilage sacs, and
even in the wider intercellular spaces, as well as on the outer
surface of the fruit. The conidia found in the internal cavities of
the fruit (probably chlamydospores) are often larger than the
normal type and always have thicker walls. Their germination
has not been observed.

The normal conidia germinate readily in water and nutrient
media, each producing a germ-tube which gives rise to a mycelium
and subsequently to conidia as described above.

Sexual organs of the Peronosporaceous type are found, singly or
in groups, in the host cells and occasionally in the mucilage cavities
of the pericarp. They arise from the intracellular mycelial
branches and may be accompanied by groups of rounded vesicles.
The oogonia average 40 by 24 and are rather thick-walled with
irregular sac-like excrescences. The antheridia are amphigynous,
surrounding the stalk of the oogonium in the manner previously
described for species of Phytophthora by Pethybridge (Sc2. Proc.
Roy. Dublin Soc., xiii, 35, p. 529, 1913) [and this Review, ii,
p. 181] and Dastur (Mem. Dept. Agric. India, v, 4, p. 177, 1918).
The general relation between the sexual organs is also similar to
that described by these authors. In ripe oogonia from desiccated
pods the antheridia are readily detachable, the walls being intact
and a distinct antheridial membrane surrounding that covering the
stalk of the oogonium.

Preliminary cytological investigations indicate that the young
oogonium is multinucleate, that little or no periplasm remains after
the delimitation of the oosphere, and that the oosphere and the
ripe oospore are uninucleate. The oospore has a fairly thin wall and
practically no epispore. All attempts to induce the germination of
the oospores gave negative results. The constant association of
both sexual and asexual fruit bodies suggested a definite relation
between them, and this was finally proved by tracing in artificial
cultures the continuity of hyphae bearing conidia with those:
bearing oogonia. Up to the present no sexual organs have been
found either in the tissues of the coffee pericarp or in artificial
media prepared from coffee fruits.

Though certain morphological characters indicate a close relation-

497

ship to the genus Phytophthora and others point to an affinity with
Muratella, the authors consider that the fungus in question differs
sufficiently from both to justify the creation of a new genus, of the
Peronosporaceae and it has accordingly been named T’rachysphaera
Fructigena, a Latin diagnosis of both genus and species being given.

BuntTine (R. H.). Mealy pod disease—a new foe to Cocoa.—
Journ. Gold Coast Agric. & Comm. Soc., ii, 2, pp. 92-94, 1 pl.,
1923.

The mealy pod disease of cacao, a scientific description of which
is published elsewhere [see preceding abstract], has so far been
recorded only from the Gold Coast. The causal fungus (Trachy-
sphaera fructigena) penetrates the most minute wounds on young
pods and destroys the beans, while it can also attack quite healthy,
intact pods which have become detached from the tree.

The fungus flourishes as a mealy, white to pinkish mass of spores
on the heaps of cacao husks from which the beans have recently
been extracted. The spores [conidia] on the outside of the pod,
transmitted by wind, rain, insects, &c., serve for the rapid propaga-
tion of the disease, while other spores [oospores] which are borne
later, serve to tide the fungus over periods of drought.

For the control of the disease it is absolutely essential to remove
and bury all diseased pods from cacao trees, and to bury all husks
as soon as the beans have been extracted, thereby serving the
double purpose of controlling the disease and providing food for
the trees, which should be kept in a good state of cultivation to
enable them the better to ward off the disease.

Rosen (H. R.). Septoria glume blotch of Wheat.—Arkansas
Agric. Exper. Stat. Tech. Bull. 175, 16 pp., 4 figs., 1921.
[Received 1923. ]

A marked spotting of the glumes and rachis of a large number
of wheat varieties has been observed in Arkansas for several
seasons. The most conspicuous symptoms appear on the outer
glumes, the affected parts of which are covered with brownish or
purplish-brown spots or blotches, with a hoary, brownish or greyish-
white centre. On the rachis the discoloured areas are found at or
near the joints, occasionally extending over the entire internode.
The attacked parts are not sharply delineated, and there is no
tendency to form streaks. The disease is not confined to glumes
and rachis, but has also been noted on the leaves, leaf sheaths, and
blades.

An examination of the diseased Arkansas material showed the
causal fungus to be identical with Septoria nodorum [see this
Review, ii, p. 211], which is synonymous with Phoma hennebergii
Kuehn and 8S. glumarum Pass. There is little doubt that the
Arkansas fungus differs from S. graminewm and SW. tritici. In
some respects it resembles Ascochyta graminicola, but a comparison
of the spores revealed considerable differences. The following is a
provisional technical description of the fungus: spots indefinite,
often elliptical, varying in colour from greyish-brown to dark or
purple-brown, often appearing light grey on a purple background:

L 3

498

occasionally a yellow, indefinite halo appears round the brownish
discoloration. Pyenidia gregarious on spots of glumes, stems, and
leaves, inconspicuous, subepidermal, opening by a small oval or
roundish pore, golden-brown at first, finally blackish, globoid, 60 to
100 » in diameter. Spores cylindrical, curved or straight, hyaline,
often adhering to and issuing from the pycnidia in the form of
serpentine threads, one to three septate, 18 to 25 by 2-8 to 3 yp,
rounded above and truncate below, with or without guttulae.

Inoculations of wheat plants, under bell jars, resulted in various
leaf and glume infections with the production of pyenidia on the
spots. The spores from the pycnidia agreed in every respect with
those observed in natural infections. Spores from the glumes
infected leaves and vice versa.

The damage caused by the disease has not yet been fully in-
vestigated, but is known to be very serious. Standard winter
wheat varieties, especially Red May and Kanred, are particularly
liable to attack. Further investigations are in progress, and in the
meantime the use of clean seed is strongly recommended.

WENIGER (WANDA). Diseases of grain and forage crops in North
Dakota.— North Dakota Agric. Exper. Stat. Bull. 166, 92 pp.,
32 figs., 1923.

In this bulletin the author describes the principal diseases of
cereals (including also flax, proso or broom corn millet, buckwheat,
and sorghum) and of forage crops (alfalfa, clovers, brome grass,
millet, timothy, Sudan grass, wild grasses, and sunflower) as
they occur in North Dakota, and then gives an account of the
measures of control to be applied against them.

The work is prefaced by a table giving the losses caused by
cereal diseases in North Dakota in the years 1919 to 1921, during
which period the average loss of wheat was 26 per cent., the
corresponding figures for oats, barley, rye, and maize being 7, 6,
2.3, and 1-8 per cent. respectively. The text is fully illustrated
and many references to original papers are given. A feature of
the report is the section dealing with the diseases of wild grasses,
which constitute an important hay crop in North Dakota, covering
over two million acres of land.

In the section on disease control, the author states that in North
Dakota the formalin method of seed disinfection has proved
extremely effective against all cereal diseases which are carried on
the outside of the grain, such as barley stripe (Helminthosporium
graminewm), wheat blights, anthracnose (Colletotrichum cereale),
and bacterial diseases, and that such enormous injuries to germina-
tion as reported in the Western States have not been encountered.
The dust treatment is not advocated at present. Very good results
have also been obtained in the control of ergot of rye (Claviceps
purpurea) by the immersion of seed in a 20 per cent. solution of
common salt (40 Ib. in 25 galls. of water) when the ergot bodies
float to the surface and can be skimmed off. The grain should
then be washed at least once with water to remove the salt, and
it is recommended that the treatment should then be followed
by the regular formalin disinfection.

499

SrakMan (E. C.). Barberry eradication prevents black rust in
Western Europe.—U.S. Dept. Agric. Circ. 269, 14 pp., 3 figs.,
1928.

The present paper, written mainly for propaganda purposes, is the
outcome of the author’s visit to Western Europe during the spring
and summer of 1922 to study the results of the eradication of
barberry bushes in the control of black stem rust [Puccinia
graminis| of cereals. In Engiand and Scotland, where the farmers
have eradicated the barberry, even without the aid of a law, black
rust is very scarce, and in every case the few unimportant out-
breaks still occurring could be traced to the immediate proximity
of a forgotten barberry bush. In Wales, on the other hand, where
the barberry has not yet’ been destroyed, the disease occurs
frequently and causes appreciable losses. The most striking results
were obtained in Denmark, which solved its black rust problem by
a law passed in 1903 for the eradication of the barberry: since
1904 there has not been a single general epidemic of the disease in
that country; the rust is seldom found, and when it does occur
a guilty barberry is also found. In some districts of Sweden there
are still large numbers of barberries, and in those regions the
attacks of black rust are very heavy. Between Stockholm and
Upsala, in the summer of 1922, fields of oats were black with rust,
which could be traced directly to the barberry bushes, such a con-
dition occurring year after year. In Holland, France, Germany,
Czecho-Slovakia, and Hungary the correlation between the
occurrence of the disease and the existence or absence of the bar-
berry was also found. Even in the most southern European
countries, Spain, southern Italy, and southern Greece, where the
climate is sufficiently warm during the winter that the summer
stage of the rust is sometimes not killed, the rust is evidently most
destructive near barberry bushes.

Lupwics (K.). Beobachtungen iiber die Bodensdurekrankheit an
Getreide. [Observations on soil acidity disease of cereals. ]—
Nachrichtenbl. deutsch. Pflanzenschutzdienst, iii, 6, pp. 41-42,
1923.

During the spring of 1923 a disease of cereals (especially rye),
which began to attract attention in 1920 and is believed to be due
to excessive acidity of the soil, caused very severe damage in
various parts of the province of Brandenburg.

The symptoms of the disease include arrested development of
the entire plant, yellowing of the leaves, a dark discoloration of
the markedly elongated roots, and a great reduction in the number
of root hairs. During periods of protracted drought the young
plants collapse entirely. In many cases the leaves become covered
with irregular, dun-coloured spots surrounded by a dark edge, such
as are associated with bright speck disease of oats [see this Review,
i, p. 421, and ii, p. 403]. Oats are usually less severely attacked,
recovery after sufficient rain being frequent, and wheat is only
slightly affected in the districts west of the Oder. The loss of
this year’s oat crop in Westhavelland is, however, estimated at 50
to 80 per cent.

There seems to be little doubt that the local practice of applying

500
e

large quantities of acid fertilizers (potassium, superphosphate, and
sulphate of ammonia) to the soil is largely responsible for the
occurrence of the disease. The deficiency of lime, from which,
according to Gisevius and other authorities, more than half the
soils of North Germany and Bavaria are suffering, has led of late
years to an increasing reduction in the German harvests. The
liberal application of lime is the only means of remedying this
serious defect and cannot be recommended too strongly.

Lipscoms (G. F.) & Corey (G. L.). A new treatment of Cotton-
seed to destroy anthracnose.—Amer. Fertilizer, lviii, 6,
pp- 82-34, 1 fig., 1923.

Repeated attempts have proved the impossibility of adequately
controlling anthracnose of cotton (Colletotrichum gossypit) by means
of fungicides, as the disinfectants are incapable of penetrating the
seed coat and reaching the fungus. The selection of uninfected
seed for planting, by the inspection of the bolls, has proved quite
impracticable, whilst the selection of resistant varieties does not
appear promising. The hot-water treatment of the seed was also
abandoned, the thermal death-point of the fungus being too near
that of the seed. The claim that the use of three-year-old cotton
seed eliminated anthracnose is not supported by the results of recent
germination tests, which have shown that infection may even occur
in five-year-old seed.

The authors’ investigations indicate that one of the most impor-
tant factors governing the vitality of cotton seed in high tempera-
tures is the presence or absence of oxygen. By thoroughly drying
and heating the cotton seed in a vacuum or any inert atmosphere,
such as nitrogen, to prevent oxidation of the fats and proteins in
the seed, they will endure 100° C. for hours without any diminution
of vitality, and even 110° to 120°C. for several hours without
destroying life. The heating for 26 hours at 100°C. of Weber 49
seed not only stimulated germination to a remarkable extent, but
also controlled anthracnose. In all the tests highly infected Weber
49 seed was used ; further experiments with other varieties are now
in progress.

The apparatus used in the drying and heating of cotton seed is
constructed as follows: A glass tube about 12 in. in length and 0-8 in.
in diameter is drawn out at the top and a small tube sealed on, to
which a rubber tubing can be fastened. The cotton: seeds are
placed in the bottom of the glass tube and, in order to hold them in
position and prevent the calcium chloride from mixing with them,
a thin layer of glass wool is placed over the seeds, and above the
glass wool calcium chloride is placed to a length of 4 to 5 inches.
A thermometer is inserted in the tube, the bulb extending to about
the middle of the cotton seeds, and the oxygen is removed by means
of a mercury or oil vacuum pump. When the manometer connected
in the circuit registers one mm. or less, the small glass tube is
sealed. After the cotton seeds have been dried in this way for
several days the tube is placed in boiling water to such a depth
that the water stands just above the seeds.

When nitrogen was substituted for air, the cotton seeds were
thoroughly dried and placed in the tube with calcium chloride

aml

501

as described above. The air in the tube containing the seeds was
displaced by nitrogen being passed in (through a tube which led to
the bottom of the seed container), until all the oxygen was expelled,
a small side tube forming an outlet for the air. Both tubes were
then sealed. After the cotton seeds had remained in the tube for
several days at the ordinary room temperature or heated several
hours in water at 50° to 60°C. they were then heated for 26 hours
in boiling water. The seeds germinated, with the result that no
anthracnose appeared and the percentage of germination was
higher than in the control.

Other samples of cotton seeds were treated in the same way
except that the seed was heated to the boiling-point of toluene,
109° C., and also to that of glacial acetie acid, 119° C., for several
hours. After heating for 10 hours at 110°C. the percentage of
germination was somewhat lower than the control and some of the
seedlings were less vigorous.

Kine (C. J.). Cotton rootrot in Arizona.—Jourin. Agric. Res., xxiii,
7, pp. 525-527, 1923.

The Texas root rot of cotton has been generally regarded as
being caused by Ozoniwm omnivorum, although definite proof of
this has been lacking. During the seasons of 1921 and 1922 the
fungus was abundant at Sacaton, Arizona, especially the conidial
form Phymatotrichwin omnivorum previously described by Duggar
(Missourr Bot. Gard. Bull. v, 3, p. 11, 1916) and a study of the
disease (which also attacks alfalfa) was therefore undertaken.

The behaviour of the fungus as shown by the spread of the
disease in alfalfa fields was very suggestive of fairy rings. The
outer ring of the circle consisted of recently dead plants, an inner
ring or ‘bare zone’ was occupied only by the stubble of dead
plants, and a patch in the centre contained re-established plants
arising from the fragments of partially destroyed crowns or roots.
It is evident, therefore, that the disease spreads from a centre in
ever widening circles, leaving the spots over which it has passed
free from the disease until re-infected. In badly infected fields the
crossing and re-crossing of the widening circles may entirely
obscure the fairy ring effect.

Under Arizona conditions abundant crops of fruiting bodies,
which enhance the resemblance to fairy rings, appear on the
periphery of the circles, shortly after the occurrence of rainy
weather. The newly formed fruiting bodies appear as felt-like
mats on the surface of the ground, or in cracks or depressions,
seldom being found more than six or eight inches from the outer
circle of recently wilted plants. They have been known to cover
more than 300 sq. ft. of soil surface in a 22-acre alfalfa field where
three or four acres of the plants had died.

In alfalfa fields it was found possible to prevent the further
spread of the disease in small, circular areas by thoroughly
saturating the soil to a depth of 4 ft. with a solution of 40 per cent.
formalin | in 100. The mycelium evidently extends a foot or more
in advance of the last affected plant, since it was found necessary
to include the soil 18 inches outside the apparent periphery in
alfalfa fields. With cotton plants the mycelium appears to extend

502

for at least 22 ft.in advance of the recently wilted ring. In no
case, however, has the disease reappeared where the treated area
extended as far as 3 ft. outside the wilted ring. The best method
of applying the treatment is to throw up a small dyke round the
affected area and pour in the solution gradually. None of the areas
in alfalfa fields treated as described above in July and August 1922
showed further disease activity after two months. In the control
areas, where the dykes were thrown up but no fungicide applied,
the infection progressed from 4 to 43 ft. during that time. In the
treated areas of cotton fields there was no reappearance of the
disease at the end of seven weeks, whereas in the control areas
the disease advanced from 6 to 8 ft. during the period.

Artificial inoculation experiments were undertaken in August
1922, normal cotton plants in healthy soil being exposed at the
roots and one-inch sections of cotton roots infected by root rot
placed in direct contact with them. After three weeks following
a rainy period one of the plants treated in this way wilted
suddenly, and on being pulled up was found to be covered with the
characteristic mycelium of the root rot fungus. Within five days
four other inoculated plants died in the same way, but owing to the
depletion of the moisture on the sides of the trench the disease
could make no further progress.

Pure cultures were prepared from the mycelium isolated from the
first wilted plant, and were used for further inoculations. Two
rows of cotton plants were separated by a trench, and on one side
ten plants were inoculated with the pure culture and four left as
controls, and on the other, the fourteen were treated with diseased
roots as described above. By 20th September the disease had
appeared in all but a few plants on both sides of the trench,
including the four controls, which were attacked by the mycelium
spreading through the soil from the inoculated plants. By Ist
October the mycelium had spread from the pure culture row
to plants growing 33 ft. away. None of the plants of a corre-
sponding series, the roots of which were inoculated with spores of
the fungus, showed any sign of infection after seven weeks.

Spores collected from fresh fruiting roots were induced to
germinate in distilled water and artificial media after several days,
but the resulting growth was extremely slow. This is not surprising,
since, if the conditions necessary for the development of the spores
were not very exacting, the enormous quantities in which the latter
are produced would long ago have ensured the universal distribu-
tion of the disease.

It is of great importance to ascertain whether the promising
results of the control experiments are applicable in other regions.

Naxata (K.) & Taximoro (S.). Studies on Ginseng diseases in
Korea.— Bull. Agric. Exper. Stat., Chosen, v, pp. 1-18, 6 pl.,
1922. [Abs. in Japanese Journ. of Botany, 1, 3, pp. 43-44,
1923. ]

The most important fungous diseases of ginseng [ Panax quinque-
foliwm), which is very extensively cultivated in Korea, are red rot
(Bacterium araliavorus Uyeda), leaf blight (Colletotrichum panici-
cola n. sp.), and amber-coloured rot (Bact. panagi n. sp.). The first-

503

named disease has already been described by Uyeda (Bull. Centr,
Agric. Exper. Stat., Tokyo, xxxv, 1909).

Leaf blight attacks leaves, stems, and seedlings, causing a reduc-
tion of 50 per cent. in the yield. The affected parts have a felt-
like appearance, in which they differ from the leaf spot caused by
Alternaria panax Whetzel. The disease is promoted by the
filtering of sunlight through the chinks of the sun-sereen and by
humidity. Spraying with Bordeaux mixture is an effective control
measure.

Amber-coloured rot causes the decay of roots and stems, to which
a water-soaked appearance is imparted. In advanced stages of the
disease only the vascular fibres remain. Infection occurs in the
winter and is therefore frequently overlooked. No effectual
remedy has been found.

Other diseases of minor importance are: sclerotial disease,
caused by a species of Sclerotinia which differs morphologically
from S. dibertiana and in growth temperature from S. panaa ;
black dry rot (Phoma panacicola n. sp.), stem-rot (Phoma punacis
n. sp.), snake-eye disease (Phyllosticta panax n. sp.); damping-otf
(Corticium vaguim [solanz]), bending-otf (Phytophthora cactorum),
dry rot (Cladosporium sp.), soft rot (Mucor sp.), and white spot

imilar to papery leaf).

HiLTNER (L.) & Lana (F.). Ueber den Einfluss der Diingung,
insbesondere mit Kalkstickstoff, auf die Starke des Brand-
befalls des Getreides. [The influence of fertilization, especially
with calcium cyanamide, on the intensity of smut attacks on
cereals. |— Mitt. deutsch. landw. Gesellsch., xxxvii, 16, pp. 253-
257, 1922.

In the autumn of 1919 a series of experiments on the effect of
the fertilization of winter wheat (Ackermann’s Dickkopf) on the
incidence of bunt [Tlletia tritict and T. levis] was carried out
at two separate branches of the Bavarian Plant Breeding and Plant
Protection Institute, near Munich, the soil in one locality being
stony with an admixture of humus, and in the other consisting of
heavy loam. Calcium cyanamide (30, 90, and 120 kg. per hect.),
Rhenania phosphate (45, 135, and 180 kg. per hect.), and potassium
chloride (60, 138, and 240 kg. per hect.), were applied to the soil
the day previous to sowing with wheat, which was infected with
the spores of bunt.

On both soils the application of potassium chloride resulted in an
increase in the incidence of attack. Rhenania phosphate (180 kg.
per hect.), however, considerably reduced the percentage of infection,
whilst the effect of the calcium cyanamide applications was much
more marked. Even at the rate of 30 kg. per hect. it reduced the
amount of infection on the stony soil from 22-6 to 4-36 per cent.
and on the loam from 13 to 10-7 per cent., while at 120 kg. per
hect. infection in both places was reduced to a trace (0-84 and 0-57
per cent.). Even more favourable were the results of fertilizing
with all three substances (calcium cyanamide 120 kg. per heet.,
Rhenania phosphate 180 kg. per hect., and potassium chloride 240
kg. per hect.), which reduced the infection to a minimum in both
localities (0-52 per cent.). Hitherto such results have only been
obtained by the use of first-class seed disinfectants.

504

Similar results were obtained in 1921 in experiments with
smutted millet, the application of 200 kg. of calcium cyanamide per
hect. reducing infection from 37-5 to 5-7 per cent. Calcium
cyanamide also controlled smut of oats [Ustilago avenae] and bunt
of summer wheat, while ammonium sulphate saltpetre gave
negative results. Applied to wheat infected with loose smut
[U. tritici], however, calcium cyanamide failed to reduce the
percentage of disease. In a further test the incidence of loose ~
smut of barley [U. nuda] was found to be greatly increased by
fertilizing with sulphate of ammonia (30, 90, and 120 kg. per heet.),
with or without the addition of basic slag and potassium chloride.
The results of a preliminary test of the effect of sulphate of
ammonia on bunted wheat were favourable.

It is suggested that calcium cyanamide should be applied to the
soil by means of a drill, or else that the seed should be encrusted
with the substance.

RiTzEMA Bos (J.). Over den invloed der bemesting met kalkstik-
stof op de intensiteit van de aantasting van het graan door
brand. [The influence of fertilization with calcium cyanamide
on the intensity of smut attacks on cereals.|—V'iyjdschr. over
Plantenztekten, xxix, 5, pp. 938-94, 1923.

Referring to the experiments of Hiltner and Lang [see preceding
abstract] on the effect of fertilizing with calcium cyanamide on the
incidence and severity of smut diseases of cereals, the author
questions the utility of the method as a general substitute for seed
disinfection with copper sulphate, which combines excellent
fungicidal properties with great facility of application.

On the other hand, there is some prospect that calcium cyanamide
might be used with advantage in the control of loose smut of oats
[Ustilago avenae], asin this case treatment with copper sulphate or
hot water is injurious to the seed and formalin only gives moder-
ately satisfactory results.

Curtis (K. M.). Two fungal diseases of the blue Lupin.—Vew
Zealand Journ. of Agric., Xxvi, 4, pp. 240-246, 9 figs., 1923.

The blue lupin (Lupinus angustifolius), which is cultivated for
cover-cropping in the Nelson District of New Zealand, has recently
been attacked by two fungous wilts caused by Botrytis cinerea and
Ascochyta pisi respectively. The diseases usually occur together
under conditions of excessive atmospheric and soil humidity, Botrytis
wilt tending to predominate. This disease is also the more
economically important of the two, since it attacks particularly the
cultivated lupin. In severe cases of stem infection the upper
portion of the plant gradually wilts, the leaves turning yellow and
eventually falling. ‘The stem lesions, which vary in length from
one half to nine inches, occur principally at soil level, but may also
be found on any part to a height of two feet upwards. The
affected epidermal cells turn brown and the diseased area assumes
a transparent appearance, the edge of the infected area sometimes
showing an abrupt rise in level as it merges into the healthy region.
As arule the stem is completely girdled by the fungus, and the outer
tissues of the plant become permeated with mycelium, The

505

development of the conidia and sclerotia is described and figured.
The latter remain on the ground near the dead plants during the
winter, giving rise to a fresh crop of conidia in the following
spring. Thus the persistence of the fungus into a second year is
secured.

The wilt caused by Ascochyta pisi is more prevalent on self-sown
than on cultivated lupins. The general symptoms are similar to
those described above, but as the plants are generally weakly from
the outset they succumb more readily than the vigorous cultivated
lupins attacked by B. cinerea. The large lesions vary from six to
eighteen inches in length and completely encircle the stem, the
numerous smaller lesions accompanying them being only about one
quarter of an inch in diameter and circular in outline. The dark
brown colour of the diseased region merges gradually into the
normal tone of the stem, and there is no abrupt change of level
between infected and healthy tissue as with B. cinerea.

The life-history of the fungus is described and figured. The
spores emerge from the pycnidia in long, thread-like masses on to
the surface of the plant, where they are freely distributed by the
agency of water. The similarity of Ascochyta on lupin to that
which occurs on pea, bean, and vetch, viz. A. pist Lib. (Mycosphae-
rella pinodes [B.and Blox.] Niessl.}, strongly suggests that the two
species are identica!, especially in view of the fact that lupins
growing near peas attacked by A. pis: were similarly affected.

Lupins should not be planted in damp soil and great care must
be taken to avoid overcrowding. Seed for planting should only be
taken from healthy fields and rotation of crops should be practised
wherever the disease has become established.

Setpy (A. D.) Fungus diseases of the Apple.—Amer. Fruit
Grower, xliii, 2, pp. 9 & 14, 1 fig., 1923.

The major bacterial and fungous diseases of the apple in Ohio are
black rot {Physalospora cydoniae], scab [Venturia inaequalis},
fireblight | Bacillus amylovorus|, blotch [Phyllostecta solitaria|,
bitter rot [Glomerella cingulata], sooty blotch and fly speck [ Lepto-
thyrium pom], and the new Phoma fruit spot. The adoption of
a regular spraying programme for apples has already given good
results in Ohio and the following schedule is recommended [see also
this Review, ii, p. 442]: (1a) Delayed dormant for control of San
José scale. (1b) Pre-pink application of Bordeaux mixture 4—6-50
for control of scab and black rot. (2) Same materials as (1b).
This is the most important spray of the season and should be
applied when the buds show pink before the opening of the blossoms.
(5) Calyx spray, to be given just after petals fall. (4) Bordeaux
mixture and arsenate of lead, applied two weeks after the foregoing.
This is a critical time in the control of midsummer diseases (blotch,
scab, black rot, and the new Phoma fruit spot). (5) Special bloteh
spray, applied 24 weeks later than (4). This may be omitted in the
absence of severe infection. (6) Second brood codiing moth spray,
Bordeaux mixture 2-4—50 and arsenate of lead, should be applied
9 to 10 weeks after (3). This is important in the control of blotch,
bitter rot, scab, sooty blotch, codling moth, and Phonuw fruit spot.
(7) In cases of severe late season infection an additional application

506

of the same material as (6) should be given during the second half of
July in southern Ohio, and late July or early August in the north
of the State.

Farey (A. J.) . Dry-mix sulphur lime. A substitute for self-
boiled lime-sulphur and summer strength concentrated lime-
sulphur.—New Jersey Agric. Exper. Stat. Bull. 379, 16 pp.,
2 figs., 1923,

The difficulties involved in connexion with the preparation and
handling of the various sulphur fungicides for fruit trees have been
largely overcome in New Jersey by the adoption of the following
formula known as the ‘dry-mix sulphur lime’: sulphur 8lb.,
hydrated lime 41b., calcium caseinate 8 oz. (for 50 gallons of spray
mixture). The results of a series of experiments in the control of
peach scab [Cladosporium carpophilum| and brown rot [Sclerotinia
cinerea| showed that spraying with dry-mix sulphur lime gave
almost complete control, being superi®r to self-boiled lime-sulphur,
atomic sulphur, and a New Jersey dry-mix sulphur lime containing
only 21b. of sulphur. Good control was also obtained with New
Jersey sulphur glue mixture (sulphur 8 lb., hydrated lime 41b., and
ground glue 80z.). Atomic sulphur and sulphur dusts caused
serious defoliation.

Dry-mix sulphur lime was also found to cause much less
russeting and defoliation of apple trees than the ordinary lime-
sulphur compounds. |

Massey (L. M.) & Fircu (M. W.). Some results of dusting ex-
periments for Apple scab and for Peach leaf curl in 1921—
1922.—Proc. New York State Hort. Soc. 1922, pp. 42-60,
1928.

Excellent results in the control of apple scab [ Venturia maequa-
lis] and codling moth were obtained in 1921 on the Greening, Fall
Pippin, Baldwin, Ben Davis, and Northern Spy varieties at Ravena,
Albany County, by the application of 15 lb. dry lime-sulphur, 10 |b.
arsenate of lead, and 75 lb. finely ground sulphur. Very satis-
factory control was also given by a sulphur-lead arsenate dust
(90:10), and by liquid lime-sulphur (1 in 15 at the delayed dormant
application and 1 in 40 at subsequent treatments) plus Jead arsenate
(24 1b. per 100 galls. of spray). Black leaf 40 was also added at
the delayed dormant and calyx sprays at the rates of 3 and 1 pint
per 100 galls. respectively. ‘The seven applications of both dusts
and sprays were given on the following dates: 13th April,
25th April, 12th May, 28th May, 27th June, 23rd July, and
19th August.

In 1922 similar experiments were carried out at Waterport and
Medina, Orleans County, on the Greening, Baldwin, Dutchess,
Wealthy, and Wolff River varieties. The best results were given
by the application of liquid lime-sulphur 1 in 40, but various dusts
also controlled the disease adequately.

The most satisfactory control of peach leaf curl [Hxoascus defor-
mans| was obtained by the application of liquid lime-sulphur
(1 in 40 and 1 in 20) and by Corona ‘coppercarb’ dust (60 per cent.
soluble sulphur and 40 per cent. inert material, 7 lb. on nine
trees).

507

Burier (O.). Bordeaux mixture. II. Stimulatory action.—Vew
Hampshire Agric. Exper. Stat. Tech. Bull. 21,49 pp., 24 tables,
1922. [Rec’d. 1923.]

After a somewhat detailed review of the work of previous
investigators on the stimulatory effect of Bordeaux mixture, the
author gives an account of his studies on the nature of the response
in sprayed plants.

Dealing first with the effect of the composition of Bordeaux mix-
ture on the dry matter formed and on the transpiration per gram
of dry matter, the author describes experiments in which tomatoes,
beans, and radishes were sprayed weekly with 1 per cent. Bordeaux
mixture in which the ratio of copper sulphate to quicklime used
was 1 to 1, 1 per cent. Bordeaux mixture in which the ratio of copper
sulphate to lime was 1 to alkalinity, and milk of lime containing
1-32 per cent. calcium hydroxide. The plants were grown in glazed
pots filled with soil containing water to 70 per cent. of saturation.
As regards the elaboration of dry matter, in six-sevenths of the
experiments the application of 1 per cent. Bordeaux mixture 1 to |
and milk of lime was accompanied by loss of weight, whilst the
plants sprayed with 1 per cent. Bordeaux mixture | to alkalinity
behaved approximately like the controls.

Spraying with 1 per cent. Bordeaux mixture 1 to 1] always
increased transpiration per gram of dry weight, an effect which
was also produced in five-sevenths of the tests with milk of lime.
Taking the experiments as a whole there was only a negligible
difference in the rate of transpiration per gram of dry matter
between the plants sprayed with Bordeaux mixture | to alkalinity
and the controls.

The data obtained from the above experiments show that the
physiological effect produced by Bordeaux mixture is due to the
ratio of copper sulphate to quicklime, and not to the amount of
copper present. The ratio of copper sulphate to lime does not,
within the limits used, affect the composition of the copper precipi-
tate, and it therefore follows that a Bordeaux mixture made with an
excess of lime should produce a response of the same order that the
calcium hydroxide present would. This is actually the case, since
1 per cent. Bordeaux mixture 1 to 1 has the same physiological
effect as 1-32 per cent. calcium hydroxide,

The author next describes his experiments on the effect of the
percentage of water in the soil on the response of plants sprayed
with Bordeaux mixture 1 to 1. Tomato, bean, and radish, were
again used. The degree of saturation in the different series of pots
ranged from 50 to 90 per cent. and the plants were sprayed at
weekly intervals. In general the application of the mixture was
detrimental to the formation of dry matter in the plants investi-
gated, especially the tomato. In the case of the latter and‘of the
bean the percentage of water in the soil in no way influenced the
result. With radishes, however, 11-2 per cent. of those grown at
70 and 80 per cent. saturation, 25 per cent. of those at 90 per cent.
saturation, and 66 per cent. of those at 50 per cent. saturation
showed an increase in dry weight as a result of spraying. The
percentage of water in the soil, however, has a modifying influence,
sprayed plants growing in too dry a soil being less deleteriously

508

affected by spraying than plants growing under more favourable
conditions as regards soil moisture.

The effect of spraying on the transpiration of plants growing in
soils of varying degrees of saturation (50 to 90 per cent.) was in-
vestigated and it was found that transpiration per gram of dry
matter produced was increased in 94-5 per cent. of the cases when
tomatoes were used, and in 68-9 and 64-3 per cent. when radishes
and beans respectively were employed. When this criterion is con-
sidered the plants fall into the same relative position as when dry
weight is taken as a criterion. Both in the case of dry weight and
transpiration per gram of dry matter the degree of illumination
was without perceptible effect.

The effect of the Bordeaux mixture on the dry weights of the
plants (also grown in soils of varying degrees of saturation) was not
materially modified by the addition of nutritive elements to the
sand in which they were grown. The transpiration of both sprayed
and non-sprayed plants, however, was less when grown in fertile
than in poor sand. Comparative observations on the coloration of
the foliage of sprayed and unsprayed plants indicate that the action
of Bordeaux mixture, whatever its nature, is indirect.

In a further series of experiments on potato, tomato, Russian
sunflower, Coleus Golden Bedder, and C. verschajfte, it was shown
that spraying has no effect on the rate of transpiration (irrespective
of the relation to dry weight) when the data are calculated for the
entire 24-hour period or for the day alone, while during the night
there may or may not be an increase in the rate of transpiration
of the sprayed plants. In the case of tomato and C. verschafftet
increased transpiration at night was recorded in all the tests; in
Coleus Golden Bedder it occurred in 50 per cent. of the experiments,
in the sunflower in five out of seven instances, and in the potato
once only. Plants sprayed with Bordeaux mixture 1 to 0-2 behaved
similarly to those sprayed with 1 to 1 under the same environ-
mental conditions, though the increased transpiration obtained was
less. Milk of lime also produced comparable results except in the
case of two experiments on the sunflower. The available data
indicate that spraying the under surface of the leaves affects the
rate of transpiration in the same way as when the mixture is
applied to the upper surface.

It was further ascertained by experiments, the technique of
which is described in detail, that Bordeaux mixture 1 to 0-2 trans-
mits 1-62 times more light than Bordeaux mixture | to alkalinity ;
the 1 to alkalinity wash 1-53 times more than milk of lime; and
milk of lime 2-2 times more than Bordeaux mixture 1 to 1. Con-
sidering the spectrum as a whole, Bordeaux mixture 1 to 1 and milk
of lime are about equally transparent and much more opaque than
Bordeaux mixture 1 to alkalinity, and there is an agreement
between the physical properties of the solutions and the response
of the plants sprayed with them. Bordeaux mixture 1 to 1 casts
an obvious shadow, and plants sprayed with it remain longer green
than the unsprayed controls, thus behaving in all respects like
shaded plants. The quality of the light received by the leaf was
found to play no part in the effect produced. An investigation of
the transmission of radiation by the solutions in question showed

. 509

that all were relatively opaque to the infra-red, Bordeaux mix-
ture 1 to alkalinity and 1 to 1 especially showing a high degree
of athermancy.

The action of Bordeaux mixtures on plants is seen from the above
experiments to be one of shade, using the term in the sense of
opacity to the spectrum as a whole. The magnitude of the physio-
logical response produced in plants by the application of Bordeaux
mixture depends, broadly speaking, on the intensity of the shadow
cast. A Bordeaux mixture transparent to the spectrum permits a
plant to grow in all respects like unsprayed plants, whereas milk of
lime and opaque mixtures cause a decrease in dry matter and an
increase of transpiration. As Bordeaux mixtures and milk of lime
are opaque to radiation of long wave length, sprayed plants, under
conditions favourable for radiation, cool less rapidly than unsprayed
ones and thus transpire more freely.

The practical conclusions to be drawn from the above facts are
as follows. When shading is injurious to the plants to be sprayed,
only a small amount of lime should be used, the composition of the
mixture being 1 to 0-5. When shading is desirable a 1 to 1 Bor-
deaux mixture should be used for the control of parasitic organisms,
and milk of lime employed when fungicidal properties are a secon-
dary consideration.

Srutzer (A.). Die Steigerung der Ernteertrage durch Beizung
des Saatgutes. [The increase of crop yields through seed
disinfection. ]—Deutsche landw. Presse, |, 5, p. 42, 1 fig., 1923.

Some years ago the writer ascertained that lead salts (lead nitrate)
were extremely effectual as a seed disinfectant. Not only were the
various parasitic organisms adhering to the seed destroyed, but
a portion of the lead remained in the epidermis and adjoining
layers of the seed, where it exerted a remarkable influence on the
development of the root system and eventually resulted in a higher
yield than that obtained from untreated seed. There was no
reduction of germination such as so frequently accompanies the
use of copper sulphate.

Similar results have more recently been secured by the use of
uspulun. Reports have been received from a Mexican cotton farm
‘to the effect that seed treated with uspulun in 1921 and 1922
yielded a cotton the fibre of which was longer and finer and
fetched a considerably higher price than that from the untreated
plants.

APPEL (O.). Die Steigerung der Ernteertrage durch Beizen des
Saatgutes. [The increase of crop yields through seed disinfec-
tion.|— Mitt. deutsch. La ndw.-Gesellsch., xxxviii, 8, pp. 37-39,
1923.

After describing the various types of seed disinfection apparatus,
the author selects a few instances in which such treatment is of
special use. Smut diseases of cereals, stripe disease of barley
[Helminthosporium graminewm], and Fusariwm disease of rye,
are now very generally controlled by immersion of the seed in
disinfectants. The farmers of Bavaria, where conditions predispose
to Fusarium disease, set the example in this direction. It is now

510

customary also to control root rot (Phoma sp.) of beet by steeping
the seed for 20 to 24 hours in 5 per cent. carbolic water or 2 per
cent. Bordeaux mixture. The immersion of various vegetable and
flower seeds in mercury preparations, especially with a view to
stimulating germination, is rapidly gaining ground.

In 1922 experiments in the immersion of seed potatoes in uspulun
gave excellent results both as regards speedy germination and
general vigour, although it is not possible to say if this result is
due to control of Rhizoctonia or to stimulation of the potato.
Further experiments with seed potatoes are planned which it is
hoped will give data as to the value of the process.

GeHRING (A. A.) & PomMsr (E.). Ueber die Wirkung verschiede-
ner Beizmittel auf Riiben. [On the effect of various disin-
fectants on Beets.]|—Deutsche landw. Presse, 1, 16, p. 147,
1923.

During 1922 a series of field tests was carried out at the Bruns-
wick Agricultural Experiment Station in continuation of the labora-
tory experiments already reported [see this Review, ii, p. 224).
Owing to the absence of root rot [Pythiwm de Baryanum and
Phoma betae| the efficacy of the fungicides in this respect could
not be put to the test, but various other points of interest were
noted.

The ‘seed clusters’ were immersed, after one hour’s preliminary ©
soaking, in germisan 0-25 per cent., uspulun 0-25 per cent., segetan
10 ce. in 1 1, or carbolic acid 1 per cent., for one hour, and sub-
sequently planted out, on 5th May, on heavy clay soil. On 19th
July it was observed that the treated plants had developed much
more regularly and vigorously than the controls. On 20th October
the plants were harvested, the highest yield being obtained from
those treated with segetan and the lowest (except the controls) from
the plot treated with carbolic acid. The highest sugar-content was
found in the beets treated with uspulun, but the other fungicides
also gave an increase over the controls.

In a second test carried out on good soil in the Weser valley, the
“seed clusters’ were immersed for one hour in 0-1, 0-25 or 0-50 per
cent. germisan. There was no increase in yield, but the sugar-
content was augmented in this case also.

Remy (T.) & VAsTERS (J.). Untersuchungen iiber die Wirkung von
Chlorphenol-Quecksilber, Sublimat und einigen andern Pflan-
zenschutz- und Desinfektionsmitteln. {Investigations of the
action of mereury chlorophenolate, sublimate, and some other
means of plant protection and disinfection.|—Landw. Jahrb.,
lviii, 3, pp. 879-480, 5 figs., 1923.

The opening section of this very comprehensive survey of the
composition, application, and effects of certain well-known fungi-
cides deals with the work of previous investigators from 1913 to
1920, with numerous bibliographical references. The second part
of the paper is devoted to the authors’ original research work at
Bonn Agricultural College, extending over the period 1915 to
1920.

511

The authors present their results under two headings: (a) the
effect on germination and yield; (b) the disinfection efficiency.

The results of the germination tests, which were carried out with
formaldehyde, copper sulphate, mercury chlorophenolate, and sub-
limate on selected seed of wheat, rye, barley, and oats, showed that
much greater injury was caused by excessive concentrations of the
fungicide than by protracted immersion in a solution of normal
strength. Unfortunately, prolonged immersion does not increase
- the protective action of the substances, or only slightly. A series
of experiments was also carried out on wheat in which the period
of steeping lasted one hour but in which the concentrations of the
fungicides varied so as to determine the safety limits for their
use. Formaldehyde, 2 in 1,000, greatly reduced germination and at
4.in 1,000 completely inhibited it. The safety-limit for formaldehyde
is between 1 and 2 in 1,000, probably nearer 1. Copper sulphate
impaired germination only at the strongest concentration of 40 in
1,000, and the limit therefore lies between 20 and 40 in 1,000.
Mercury chlorophenolate in no case reduced germination, which
was, however, somewhat delayed at the highest concentra-
tion, 2 in 1,000. Sublimate adversely affected germination at 1 or
2 in 1,000, and slightly retarded it even at the lowest concentration
of 0-5 in 1,000. The final results of the latter treatment, however,
were satisfactory. In judging these results it must be remembered
that the susceptibility of cereals to the action of the different fungi-
cides varies considerably from one season to another and is also to
some extent an individual peculiarity. The locality of origin and
the variety of grain must also be taken into consideration.

Disinfection tests were carried out on wheat and other cereals
inoculated with Tilletia caries, Rhizopus nigricans, Aspergillus
niger, Penicillium glaucum, Fusarium metachroum, and I. rubi-
ginosum. Mercury chlorophenolate was almost uniformly more
effective than sublimate in the control of all the fungi tested.

Laboratory and field experiments were made on naturally infected
seed of wheat, oats, barley, rye and beet to test the value of germi-
san, uspulun, and formaldehyde (separately and in combination),
fusariol,and copper sulphate. No improvement in the germination
of seed which had been damaged during harvesting or storage was
ever obtained by any of the substances tested. In the case of rye
infected with Fusariwn [nivale], mereury chlorophenolate, sub-
limate, and formaldehyde, stimulated the germination. Good results
in the control of the diseases were secured with formaldehyde (0-5
in 1,000). Mercury chlorophenolate and sublimate were equally
effective in the control of Fusariwm and stripe disease of barley
[| Helminthosporium gramineum]. Sublimate was slightly superior
to mercury chlorophenolate in the control of bunt. Sprink-
ling the seed with sublimate, 0-787 in 1,000, and mercury
chlorophenolate, 1 in 1,000, very considerably reduced the in-
cidence of bunt, but even better results were obtained by immersion
at much lower concentrations (mercury chlorophenolate 0-25 in
1,000, and sublimate 0-098 in 1,000).

In 1921-22 complete control of bunt was secured by germisan
25 in 1,000, formaldehyde 1 in 1,000 (or 2 in 1,000 with subsequent
rinsing), and sublimate 1 in 1,000. Approximate freedom from

512

infection was obtained by immersion in uspulun 2-5 in 1,000, in
a mixture of germisan 0-83 in 1,000+uspulun 0-83 in 1,000+
formaldehyde 0-67 in 1,000, and in fusariol as directed. None of
the preparations was completely effective in guarding against subse-
quent reinfection; the best results from this point of view were
obtained by the use of copper sulphate. Solutions of uspulun, subli-
mate, germisan, and formaldehyde could safely be used three times
in succession. In no case were uninjured spore balls completely
destroyed, though in a recent experiment (1923) copper sulphate
almost entirely inhibited their germination. Low concentrations
of sublimate and uspulun even appeared to stimulate the germina-
tion of the balls. The removal of the spore balls before or during
treatment is therefore an essential preliminary.

Cattle, pigs, and poultry can safely be fed on grain treated with
uspulun, sublimate, formaldehyde, copper sulphate, or germisan.

Uspulun deserves special consideration at the present time on
account of its relative cheapness [British price 13s. Od. per |b.]
It has the further advantage of causing comparatively little damage
even at excessive concentrations. Germisan [7s. 10d. per 500 gm.
or 1-11b.] has also given excellent results, which, however, require
further confirmation before the preparation can be widely recom-
mended.

Durrenoy (J.). La lutte contre les maladies des plantes par la
sélection des races immunes. [The campaign against
diseases of plants by the selection of immune varieties. |—Rev.
Bot. appliquée, iii, 20, pp. 241-246, 1923.

In a brief survey of the practical importance of the selection of
immune or resistant varieties of plants in the fight against disease,
the author gives a number of well known examples of the success
of this method. Its value has been fully demonstrated in such
cases as wart disease of potato (Synchytriwm endobioticum), cereal
rusts, sugar-cane diseases, chestnut diseases, and the like. In
certain instances, however, such as Sclerotinia trifoliorum, little
success has been met with, since all varieties of clover appear to be
susceptible to this fungus, and the same is true of Plasmodiophora
brassicae on cabbage.

DoouiTrLe (S. P.) & WALKER (M.N.). Cross-inoculation studies
with Cucurbit mosaic.—Science, N.S., lvii, p. 477, 1928.

Cross-inoculation experiments with cucumber mosaic have been
continued with the result that 8 genera, 23 species, 8 varieties, and
96 horticultural varieties from Europe, Asia, and Africa are now
known to be susceptible to the disease. In the genus Citrullus
infection was secured only in the case of the green-seeded citron.
It was shown in an earlier paper [see this Review, i, p. 122] that
cucumber mosaic was transmissible to Martynia louisiana,
pepper (Capsicum annwum), and milkweed (Asclepias syriaca), and
more recently pokeweed (Phytolacca decandra) was also found to
be susceptible. Further studies have demonstrated that cucumber
mosaic is readily transmissible to these hosts and back to the
cucumber. ‘The disease has also been transmitted from milkweed
to both Martynia and pepper and back to milkweed. The most

hee

5138

uniformly successful method of inoculation was by means of aphids.
Inoculation with the crushed tissue or expressed juice of mosaic

plants gave satisfactory results.

The authors also found that cucumber mosaic was readily
transmissible to tobacco through pepper and vice versa, the pepper
apparently acting as an intermediate host. Their numerous direct
inoculations from cucumber to tobacco have hitherto given negative

results, though Elmer [see this Review, ii, p. 21] reports the

successful inoculation of cucumbers with tobacco mosaic and vice
versa.

A high percentage of infection was secured in several series of
inoculations on the cucumber from potato plants previously inocu-
lated with cucumber mosaic. Potato plants inoculated from the

‘cucumber in 1921 yielded tubers which when planted in the green-

house during the past winter produced plants showing symptoms
of mosaic. The results of preliminary experiments indicate that
potato mosaic may possibly be transmitted to the pokeweed. During
the summer of 1922 it was discovered that cucumber mosaic was
transmissible also to the pigweed (Amaranthus retroflecus) and a
cultivated ground cherry (Physalis sp.).

Kortina (J. E.) & Coons (G. H.). Trypanosome-like bodies in
Solanaceous plants.—Phytoputh., xili, 7, pp 324-3825, 1923.

Nelson’s paper relating to the occurrence of protozoa in plants
affected with mosaic and related diseases [see this Review, ii, p. 227 |
stimulated the authors to investigate whether similar phenomena
were to be met with in potato and other plants affected with other
degenerational diseases.

Diseased material from plants showing severe symptoms of potato
mosaic, streak, and leaf roll was killed and fixed with both chrom-
acetic and Zenker’s solutions. Longitudinal sections 7 » thick were
prepared and stained with Heidenhain’s haematoxylin.

The phloem cells of the diseased potato plants were found to
contain inclusions resembling the trypanosome-like bodies described
by Nelson, and similar bodies were also found in the phloem cells
of midribs and lateral veins of leaves of tobacco and petunia plants
affected with mosaic.

As a control the same work was done on material from healthy
potato and tomato plants. In order to ensure the supply of healthy
potato material for these tests, the stock from which it was taken was
indexed during the winter 1921-1922 (that is, an eye of a tuber
was sprouted and grown in the greenhouse to about 10 inches in
height and if any plants showed disease the parent tubers were
rejected). The stock thus obtained was grown in an isolated plot in
1922 and found to be healthy. ‘Some of the progeny of this stock
was indexed again during the winter 1922-1923 in a greenhouse.
No aphids were observed on the plants selected for study, nor were
signs of mosaic or leaf roll detected by the time the plants had
reached a height of 8 inches and the material was cut and fixed.
The variety used, Bliss Triumph, allows of an easy and prompt
recognition of either mosaic or leaf roll. Tomato material was
obtained by planting disinfected seed on agar in Petri dishes and
transferring the seedlings after germination to test tubes (plugged

514

with cotton) containing Shive’s nutrient agar. Allard and others
contend that tomato mosaic is not transmissible through the seed,
so the precautions taken are believed to exclude the possibility of
infection.

The phloem elements of healthy potato and tomato plants were
found to contain inclusions similar in size and form to those found
in severely diseased material and equally abundant. No degree of
uniformity was possessed by these bodies in either diseased or
healthy material. All attempts to show definite structure by
using such protozoal stains as Wright’s, Romanowski’s, tetrachrome,
&e., failed, the bodies’staining a uniform blue, nor has it been
possible to prove motility, in sections of fresh material or in ex-
tracted juice of diseased or healthy plants.

The conclusion is reached that the correlation of the trypano-
some-like bodies described by Nelson with mosaic and leaf roll has
not been proved.

Doo.itt_e (S. P.) & McKinney (H. H.). Intracellular bodies in
the phloem tissue of certain plants and their bearing on the
mosaic problem.— Phytopuath., xiii, 7, pp. 326-829, 1 pl., 1923.

This paper records the results of the authors’ study of phloem
tissue of both mosaic and healthy plants. The material consisted
of stem and petiole phloem of navy beans, tomatoes, cucumbers,
and red elover, both healthy and mosaic-infected, and of healthy
garden peas, sweet peas, and alfalfa. In most cases free-hand
sections of fresh material were studied side by side with material
fixed, embedded, sectioned, and stained by the usual methods.

The precautions taken in order to obtain mosaic-free plants are
described. The mosaic-free bean and tomato plants used for the
experiments were grown in an isolated greenhouse at the University
of Wisconsin, in which no mosaic plants were found either before
or after the material for study was removed, although light and
temperature conditions were favourable to the development of the
disease. As an additional safeguard, healthy tomato plants were
inoculated with the juice from the healthy plants sectioned, but the
former developed no mosaic, while similar healthy plants inoculated
at the same time with material from the mosaic plants studied
developed the disease. The other plants were selected with
similar care.

Certain intracellular bodies very similar to those described by
Nelson as protozoa in the phloem of certain mosaic plants, were
found in the phloem of both mosaie-free and mosaic-infected plants
[see also preceding abstract]. In beans, three to six weeks old,
they were discovered in fresh and in microtomed material, the
latter being stained either by Fleming’s triple stain or by Heiden-
hain’s iron-alum haematoxylin. The bodies were found singly in
the sieve-tubes and adjoining cells, oriented longitudinally. In shape
they varied from irregularly ovoid to narrowly ellipsoid and
usually had one or more slender strands extending from each end,
sometimes to the ends of the cells and sometimes shorter distances
from the bodies. Though the stains employed should have brought
out cytological details if these had been present, the characteristic
nuclei, blepharoplasts and rhizoplasts of protozoa were not observed

CC EE VT

Fe Se nd

515

by the authors, nor were they able to note in free-hand razor
sections of fresh material an active motion of the bodies such as
might suggest that of a protozoon. Similar bodies were observed
in healthy and mosaic-infected red clover, as well as in healthy
garden peas, sweet peas, and alfalfa, except that the terminal
strands were only occasionally seen in clover and alfalfa and not at
all in garden or sweet peas.

Strasburger (Histologische Beitrdge, iii, pp. 193-194, Jena, 1891)
reported finding in the sieve-tubes of Robinia pseudacacia certain
slime-bodies which resemble in many respects those found by the
writers in beans, clover, garden peas, and sweet peas. He described
them in some detail and found them to colour a yellow-brown with
iodine and to react intensively to Millon’s reagent, the threads
being only weakly stained. Strasburger’s original figures are
reproduced by the authors.

Haberlandt also states that these bodies occur generally in the
Leguminosae, but not in the Cucurbitaceae, this statement agreeing
with the findings of one of the authors, who was unable to detect
them in the phloem tissues of stems and petioles of either mosaic-
infected or mosaic-free cucurbits.

The intracellular bodies, which appear to be identical with those
interpreted by Nelson as trypanosome-like protozoa, are not found
as regularly in the tomato as in the bean, but they seem to be as
abundant in the mosaie-free as in the mosaic-infected tissues, and
the most careful investigation has failed to reveal structure typical
of trypanosomes or other protozoa. Both healthy and diseased
plants show the cytoplasm of the phloem cells frequently collected
in lightly stained, long or short, irregular, spiral, wavy forms in all
stages up to the deeply stained forms referred to, but an undulating
membrane characterizing the trypanosomes has never been observed
by the authors.

Baitey (I. W.). Slime bodies of Robinia pseudo-acacia L.—
Phytopath., viii, 7, pp. 382-333, 1 pl., 1923.

Robinia pseudacacia is characterized by having curious ‘ slime-
bodies’ (Strasburger’s Schleimklumpen) [see preceding abstract]
in its sieve-tubes, which stain intensively in Millon’s reagent and
vary greatly in size and shape during different stages in the
differentiation of the sieve-tubes. At first small, slender, spindle-
shaped structures, they enlarge later, frequently tending to be
bifurcated at the ends and are held in place by slender threads
attached at the ends of the spindle. As the ‘slime-bodies’ enlarge
laterally, these strands become thicker and more conspicuous. The
author thinks that the structures described and figured by Nelson
in the phloem of bean and clover affected with mosaic are identical
with the slime-bodies occurring normally in the sieve-tubes of
Robinia and other Leguminosae. All the forms described by
Nelson are taken on by the slime-bodies of R. pseudacacia during
various stages in the differentiation of the phloem, although in the
case of these large trees they are somewhat larger in size.

The movements recorded by Nelson in fresh sections of living
material mounted in boiled water must be considered normal, as the
stresses and strains in the various tissues are changed in cutting

516

the sections, the osmotic and other equilibria being also disturbed
by immersion in water. The liquid or semi-liquid contents of the
cells must also contribute to this disturbing influence through their
circulatory motion.

Kororp (C. A.), SEVERIN (H. H. P.), & Swezy (OLIVE). Nelson’s
spiral bodies in Tomato mosaic not protozoa.—Phytopath., viii,
7, pp. 330-331, 1928.

The authors record their total disagreement with Nelson’s inter-
pretation of the bodies found in plant tissues affected with certain
mosaic diseases [see also preceding abstracts]. In material from
both healthy and mosaic-infected tomato plants, fixed in hot
Schaudinn’s fluid and stained in the usual way in iron haematoxylin,
structures clearly similar to those described and figured by Nelson
were found, but the absence (1) of the undulating membrane, (2) of
the flagellum having a definite, clear-cut, marginal fibril arising
from a centrosome, and (3) of the parabasal body near the end of
the fibril and joined to the centrosome by the parabasal rhizoplast;
exclude the possibility of their being trypanosomes, nor is their
spiral form characteristic of either trypanosomes or of any known
protozoa. Other characters generally associated with the latter
bodies are also lacking. These spiral bodies of the tomato do not
belong to the same category as the clearly established trypanosomes
of the latex of Euphorbiaceous plants.

No evidence of motility was detected at any time by the authors
in the spiral bodies, but it is stated that occasionally reagent
bottles, particularly those containing physiological salt solution, in
use in the laboratory, become contaminated with a species of Bodo,
a small, rapidly-moving flagellate, and these might appear in pre-
parations made up with such contaminated solutions, deceiving the
observer as to their origin.

Similar spiral bodies have been found by the authors in mosaic-
free seedling tomato plants and in the diseased phloem of older
plants, with the difference that in the former they were smaller,
but whether this has any connexion with the age or the disease of
the plant the authors are unable to say; the peculiar relations of
these spiral structures, in their elongated, trumpet-shaped phase, to
the sieve-plates in some instances, their relative homogeneity, and
their spiral structure, induce, however, the belief, that they are
dexiotropic cell contents of an albuminoid nature.

Doran (W. L.). Effect of external and internal factors on the
germination of fungous spores.— Bull. Torrey. Bot. Club, xlix,
11, pp. 313-336, 2 diag., 1922.

In this work the effect of various factors on the germination of
spores of the following fungi was studied: conidia of Venturia in-
aequalis, Sclerotinia fructigena, Alternaria solani, Botrytis cinerea,
and Rhizopus nigricans, aecidiospores and uredospores of Cronar-
tium ribicola, aecidiospores of Gymnosporangium clavipes and
teleutospores of Puccinia malvacearum. In all cases except that
of A. solani the spores were obtained fresh from the living host,
being thus presumably possessed of their full natural vigour.

In the experiments (the technique of which is described) on the

517

relation of the viability of the spore to its age, it was found that
mature spores (especially those which have just reached maturity)
can germinate through a wider range of environmental conditions
than either immature or old ones. As the spores advance in age
viability decreases, sharply at first and then gradually. The
longevity of spores is dependent on conditions of storage after
detachment from the host, moisture being of more importance than
temperature in this connexion.

Dealing with various external factors on germination the author
first discusses that of temperature. A table-is given of 33 records
of the cardinal temperatures of various fungi. From this it is seen
that the minimum temperatures for spore germination are 1° to
7-4° C., the optima 13° to 23-1° C., the maxima 22° to 39-6°C. The
Phycomycetes can germinate at the lowest minimum temperatures,
followed in order by the uredospores, aecidiospores, and teleuto-
spores of the Uredinales. Aecidiospores have the lowest optimum
temperatures for germination, followed in order by uredospores,
conidia of Phycomycetes, teleutospores, and spores of Fungi Imper-
fecti. The writer determined the minimum temperature for the
germination of conidia of Venturia inaequalis as 3°, the optimum
14°-15°, and the maximum 31°C., the decrease in germination
being more rapid from the optimum to the minimum than from the
optimum to the maximum. From a study of the published figures
the length of time required for spore germination was found to be
about 12 hours, the different groups varying from 4 to 21 hours.
and the author adds his own figures for six other species which
varied from 2 to 27 hours. The nearer all conditions approach to
the optimum, the shorter is the time required for spore germination.
With regard to oxygen relations, the literature is reviewed on this
subject and the author points out that competition or crowding
inhibits germination and this is attributed to a deficiency of oxygen.
The spores of the fungi studied germinated indifferently in light
or darkness. Precipitated moisture was found to be essential to
the germination of the conidia of S. fructigena and Peronosporu
pygmaea, which was also studied in this connexion, but G. clavipes
germinated equally well merely in water vapour. In the case of
A. solani and V. inaequalis, both germinated very poorly in water
vapour but very well in a drop of distilled water.

A bibliography of 59 titles is appended.

SPIECKERMANN (A.). Wie kann die weitere Verbreitung des
Kartoffelkrebses in Deutschland verhindert werden? {How
can the further spread of wart disease of Potatoes in Germany
be checked ?]|—WMitt. deutsch. Landw.-Gesellsch., xxxviii, 13,
pp. 175-178, 1923.

Wart disease of potatoes [Synchytriwm endobioticum|] first began
to cause serious alarm in Germany in the summer of 1922, when it
appeared on a large scale in the potato-growing districts east of
the Elbe. The disease had occurred in a sporadic form in Germany
since 1908, but until recently it was confined almost entirely to
small holdings in the manufacturing districts, and therefore did not
materially affect the agricultural population. Subsequent develop-
ments, however, have thrown an entirely new light on the situation

518

and demonstrated the need for the most stringent legislative
measures to combat the further spread of the disease.

The symptoms of the disease and life-history of the causal
organism are briefly described. It is pointed out that, besides the
usual agents of dissemination (rain, labourers, and animals), particles
of infected soil adhering to apparently healthy tubers are respon-
sible for a certain amount of infection (10 per cent. in recent tests
in Westphalia). The danger of infection by this means is particu-
larly great from starch factories, where potatoes of widely varying
origin are washed before use.

The amendment and extension of the legislative measures against
wart disease which came into force in September 1922 [see this
Review, ii, p. 335] will doubtless cause serious inconvenience to
distillery owners and others, but from the standpoint of national
welfare they are absolutely justified.

All attempts to control wart disease by seed tuber disinfection
have hitherto given negative results, and although further experi-
ments on these lines are in progress, the only reliable method of
suppression at present is the cultivation of immune varieties.
Among the latter, Paulsen’s Juli and Goldperle combine early
maturity with delicate flavour and yellow flesh. Modrow’s
Johannsen and Preussen are good medium-early varieties, though
both are unfortunately apt to ‘degenerate’. Immune early varie-
ties with white flesh are Thiele’s Friiheste, Kuckuck, Magdeburg
Blaue, and possibly also Biirkner’s Fritheste. There are as yet no
immune medium-early, white-fleshed varieties, but a number of
valuable medium-late ones, the best of which is Richter’s Jubel,
followed by Pepo, Arnica, Marshal Hindenburg, Helios, and Nepeta.
Parnassia deserves special mention as being the only immune
variety with a high starch content. This list will doubtless be
amplified by investigations now in progress.

In 1922, 30 per cent. of the potatoes grown in Brandenburg were
immune varieties, in Pomerania 31 per cent., and in Hanover and
East Prussia 12 per cent. During the last three years the area
occupied by immune varieties has increased considerably in all
parts, especially in Silesia and Brandenburg. °

The author regards the danger of the importation of wart
disease with consignments of potatoes from abroad as comparatively
slight. Of far greater importance than frontier inspection, essen-
tial though it be, is the reduction of the infected area at home.
This object can be attained only if the legislative measures are
reinforced by the willing co-operation of all classes concerned.

SCHRIBAUX. Sur la dégénérescence de la pomme de terre et sur
les moyens de la conjurer. [The degeneration of the Potato
and the means of preventing it.|—Comptes rendus Acad.
Agric. de France, ix, 3, pp. 95-97, 1923.

Potato cultivation in France appears to be passing through
a serious crisis as potato growers, in addition to mildew and filosity,
now have to contend against various insidious and obscure diseases,
such as verticilliose, rhizoctoniose, leaf roll, curl (frisolée), &e.

Experiments conducted at Grignon by Ducomet. in 1921 and
1922 have shown that none of the 180 varieties tested was abso-

i i la ee

519

lutely immune from ‘degeneration’ diseases. In view of the here-
ditary character of these diseases, individual (not mass) selection of
healthy tubers between the end of June and middle of September is
absolutely essential. Of 440 ‘ families’ from 40 varieties cultivated
by Ducomet, three-quarters had to be eliminated; in 11 varieties
not a single ‘family’ was preserved. These figures show the
necessity of rigorous and persistent individual selection.

Botues (J. O.). Die Verwendung unreifer Kartoffeln als Saatgut.
[The use of unripe Potatoes for seed. |—Deutsche landw. Presse,
I, 13, pp. 118-119, 1923.

The use of unripe potatoes for seed has given very conflicting
results both in Germany and elsewhere. In a series of experiments
carried out by Dr. Munter at Halle during the years 1918 to 1921
there was a marked improvement in the yield, especially of the
Wohltmann variety, from unripe tubers on soil where potatoes
-are liable to ‘degeneration’ but in stocks free from such diseases no
such improvement took place.

In the writer’s opinion this increased yield is due to the fact that
the unripe tuber is severed from the vegetative portion of the plant
before the virus of mosaic and other similar diseases has time to
pass from the former to the latter; such a tuber would in all
probability produce sound offspring,

Newton (R. G.). Experimental work with potatoes. — Agric.
Journ. Brit. Columbia, viii, 4, pp. 80-81 & 86, 1 fig., 1923.

For the last four years experimental work on virus diseases of
potatoes has been in progress at the Invermere Experimental
Station, which is situated at an altitude of 2,700 ft. in the Kootenay
Valley. Varieties affected with mosaic to the extent of 100 per
cent. have increased in yield during the period under review and
shown no signs of degeneration. This is believed to be due much
more to environmental and climatic conditions than to selection.
Leaf roll, curly dwarf, and allied diseases can be virtually
eliminated by roguing and rigid individual tuber selection at plant-
ing time.

In spite of the general adoption in British Columbia of seed dis-
infection with corrosive sublimate, Rhizoctonia causes a heavy
reduction in the yield. Common scab [ Actenomyces scabies] is also
very severe, but may be controlled, at any rate on the resistant
Cambridge Russet variety, by the application of 600 lb. of agri-
cultural sulphur per acre.

MrtLarp (W. A.). Common scab of Potatoes II.—Ann, Appl.
Biol., x, 1, pp. 70-88, 2 pl., 1923.

Following his previous work [see this Review, ii, p. 138] on
common scab (Actinomyces scabies) the author in this paper deals
first with green manuring treatment for the disease, secondly with
the action of liming on the organism, and thirdly with theoretical
considerations arising from the above.

The three manuring experiments recorded were carried out in

520

1920 when the amount of disease present was small, but they indi-
cated that green manuring was very effective in reducing scab.

Further experiments in 1921 using seeds hay (23 and 5 tons per
acre) and spent hops as substitutes for green manure showed that
the former was very little use, while in the latter case the heavier
dressing gave very good results and further trials with this appar-
ently worthless product are warranted.

The effect of lime dressings on scab varies with the reaction and
type of soil to which they are applied. In the experiments
described, two acid soils and two approximately neutral soils were
limed. In the former ease, scab followed, whilst in the latter case
there was no effect, and there is little doubt that many of the con-
flicting statements regarding the results of liming might be recon-
ciled if the initial soil reaction was known. The lime requirement
serves as a useful guide in predicting the action of lime on scab.

Further experiments are described which show that the appear-
ance of scab following liming may be counteracted by green
manuring.

In examining the theories advanced to account for the occurrence
of scab and its prevention by green manuring the author first
discusses the soil reaction theory. He has not found the hydro-
gen-ion concentration of the soil to be a direct factor in controlling
scab, a statement which is supported by the fact that (1) scab,
although usually absent from acid soils, may occur in soils with as
low a Py value as 4-4; (2) in more nearly neutral soils the Py
value of the soil and the incidence of scab are not related, as is
shown by the fact that one soil having a hydrogen-ion exponent of
7-0 may yield absolutely clean crops, whilst another with the same
Py value may bear very scabby crops, a distinction which cannot
be explained by supposing the former soil to be virgin and uncon-
taminated with scab; (3) the application of green manure seems
to decrease rather than increase the hydrogen-ion concentration of
the soil.

The most plausible explanation of the established facts in con-
nexion with the occurrence or absence of scab is thought by the
author to lie in his preferential food theory. If the soil is well
supplied with vegetable matter in a palatable state for the Actino-
myces, the crops will be clean. The organisms remain saprophytic
until their natural food supplies are exhausted, and only under the
stress of hunger will their parasitic tendencies be developed. The
freedom of peat soils from scab may be explained by the large
natural reserve of organic matter present, and whilst the author
agrees that high acidity depresses the Actinomyces flora, a peat
soil which has a Py value of 7:1 was found to contain 5,000,000.
organisms per gram and yielded clean crops. Scab is most preva-
lent on light sandy and gravelly soils, where the well aerated
conditions bring about the rapid disappearance of farmyard and
vegetable manure. The fact that the incidence of scab sometimes
resulting from liming may be counteracted by heavy dressings of
green manure also supports the author's theory.

Dry seasons are more favourable to scab than wet, no doubt
owing to the higher soil temperature in dry weather, but rainfall,
which modifies the air content of the soil and thus regulates the

521

development of the strongly aerobic scab organisms, is the most
important factor, as is seen in clay soils where the disease is almost
entirely inhibited by a wet season.

Goss (R. W.). Relation of environment and other factors to
Potato wilt caused by Fusarium oxysporum.—<Agric. Exper.
Stat. Nebraska Res. Bull. 23, 84 pp., 5 figs., 1928.

A critical review of the literature dealing with potato wilt
caused by Fusariwm oxysporum shows that the general opinion of
the widespread activity and serious character of the disease is based
upon insufficient data. Much of the experimental evidence is con-
tradictory and there has been a general failure to reproduce the
symptoms of the disease as it oceurs in the field. On the whole,
the available data do not justify the conclusion that F. oxysporwm
is an extremely virulent parasite, but rather suggest a lack of
knowledge of the influence of various factors upon the occurrence
of the disease. The object of the present work was to determine
the effect of some of the complex of factors which influence the
development of the disease.

There are three methods of infection of potato plants by F. oxy-

sporwm : (1) infection from the soil through the seed tuber; (2)
from the soil through the roots and stem; and (3) infection from
the seed tuber. The results of experiments showed that the second
is the most prevalent method of infection in Michigan and
Nebraska. The distribution of the disease is widespread, the
organism being universally present even in virgin desert and forest
soils. The accurate determination of the losses caused by this
disease is almost impossible owing to the complexity of the factors
governing its incidence and to the liability of confusion with other
troubles. Of recent years the highest reported losses in the six
leading potato-growing States are 6 and 5 per cent. in 1918 and 3
per cent. in 1919 and 1920.
, As a preliminary to the study of the influence of temperature on
the disease, the growth-temperature relations of the organism in
pure culture were investigated. It was found that different strains
of F. oxysporum vary by at least 5°C. in their optimum tempera-
ture for development, the differences being more marked in liquid
than in Petri dish cultures. By the use of different liquid media
it was possible to cause a reduction of 5° to 10°C. in the optimum
temperature for growth. These data may account for the varying
results reported by different investigators, and also show that the
manifestation of the disease at certain temperatures may depend on
the strain of organism studied.

Pathogenicity tests indicated that F. oxysporum is not a very
virulent parasite and they also showed that potato plants are most
susceptible to infection in the early stages of growth. Under
conditions favourable to the plant infection may often occur
without producing any external symptoms of the disease. On the
other hand, a discoloration of the vascular system of both stem and
tubers is often apparent under conditions of high temperature and
low soil moisture, even in the absence of a specific causal organism.
It is, therefore, not a reliable indication of infection by F’. oxysporwm
unless associated with a wilting of the plant. Only a small

522

percentage of tubers with a vascular discoloration contain Ff.
oxysporum, and such tubers do not usually reproduce the disease
except under conditions very favourable for this type of infection.
They should not, however, be used for seed, as they produce weak
plants which are very susceptible to soil infection.

A large number of experiments are described showing the effect
of soil temperature and moisture on the disease, but the amount of
infection secured by artificial inoculations was so small that definite
interpretations of the results were difficult to make. Temperatures
of 18°C. and below, however, are very unfavourable for the
development of the disease, the amount of infection increasing with
a rise in the soil temperature up to 30°C. The disease develops
most rapidly when the temperatures are too high for the vigorous
growth of the host. Plants started at a temperature of 18°C. and
later transferred to higher temperatures showed as much disease as
those kept at a constant high temperature. Conversely, plants
started at a high temperature and afterwards transferred to a low
one showed practically no symptoms of disease although the
organism was present to a slight extent in the finer rootlets.
Constant low soil moisture is unfavourable for infection. After
the plants have become infected, however, a reduction of the soil
moisture accelerates the wilting of the plant. With increasing
soil moistures the amount of rotting of the stems and roots of
infected plants increases and the wilting symptoms are less marked.
The results of experiments with seed inoculations under three
different environmental conditions showed that the greatest amount
of disease developed in the plot with low soil temperatures during
the early period of growth, and with a decreasing soil moisture
content and rising soil temperatures in the later stages. The
application of two irrigations during the later period of growth
rendered the plants more vigorous and reduced the amount of
disease. Practically no disease developed in another plot with the
same general type of temperature and moisture curve as in that
showing the greatest amount of disease, but with much higher
temperatures and soil moistures throughout the experiment.

Cook (F. C.), The influence of copper sprays on the yield and
composition of Irish Potato tubers.—U.S. Dept. of Agric. Bull.
1146, 24 pp., 1923.

The results of experiments with (a) ordinary Bordeaux spray,
prepared by mixing milk of lime and copper sulphate solutions ;
(b) Pickering spray, prepared by mixing a saturated solution of
lime water with a dilute solution of copper sulphate; and (c) a
barium water spray, prepared by mixing barium hydroxide with
a dilute copper sulphate solution, showed that the tubers of sprayed
potato plants were usually higher in solids, starch, and nitrogen
than those from the untreated controls. The starch content of the
sprayed plants increased approximately 50 per cent. as the tubers
matured, while the dextrose disappeared and the sucrose was
materially reduced. The early varieties of potatoes showed
a decrease in their sugar content and a corresponding increase in
their starch content in the copper-sprayed tubers during the early
stages of development. In sprayed plants also the proportion of

523

insoluble ash decreased during the growth of the tubers, though
the total ash content remained constant. The total nitrogen
increased, and the figures for soluble, coagulable, and mono-amino-
and amido-nitrogen increased as the tubers matured. The pro-
portion of tubers to green vines appeared to be higher for sprayed
than unsprayed plants.

Average data for seven States obtained in 1919 showed the food
value of copper-sprayed potatoes to be equivalent to a yield of
839 lb. per acre more than that for those unsprayed. Two factors,
increased yield (48 bushels per acre) and an increase of solids (5-6
per cent.), are involved.

Some results obtained at Arlington Experimental Farm, Virginia,
comparing a 10-10-50 with a 5-5-50 Bordeaux, indicate that the
former spray has no advantage over the latter, and may possibly
furnish an excess of copper for the maximum stimulating or
_ protective effect. Results from New Jersey, where a 44-50
Bordeaux spray was applied eight times, compared with results from
only four applications of the same mixture, show that the tubers
were lower in solids in the former than in the latter case. This
again suggests that an excess of copper, in the absence of late
blight (Phytophthora infestans), mitigates the stimulatory action of
the spray.

Tubers from several varieties of potatoes grown in the north
were higher in solids than tubers of the same varieties grown in
the south.

A larger yield of potatoes was secured from copper-sprayed than
from control or non-copper-sprayed vines, the three sprays tried
giving essentially the same increase in yield and in solids.

’ FRANCHINI (G.). Action des latex végétaux sur différents proto-
zoaires. [The action of plant latex on various protozoa.|—
Bull. Soc. Path. exot., xvi, 4, pp. 256-263, 1923.

The results of further experiments on the action of plant latex
on various trypanosomes and other protozoa [see this Review, ii, pp.
229, 230] showed that trypanosomes of human origin maintained
their vitality longest in the latex of different species of Euphor-
biaceae, Asclepiadaceae, Apocynaceae, Artocarpaceae, and Urticaceae.
Whereas the latex of certain plants, e.g., Asclepias cwrassavica,
Gomphocarpus fruticosus, and an undetermined species of Huphor-
bia rapidly produced a fatal effect on the protozoa [excluding try-
panosomes], that of Yanghina venenifera (Apocynaceae), which
inhibits the development of bacteria, conserved their vitality. The
trypanosomes lived longer in the latex of any of the plants used
than in the physiological or citrated solutions.

Crithidia melophagi and C. gerridis were more resistant to the
action of the latex than most of the trypanosomes. The vegetative
forms of the amoebae of human dysentery, Lamblia (Giardia)
hominis, L. muris, Trichomonas hominis, T. mwris, Cercomonas
hominis, Hexamitus muris, and Tetramitus muris rapidly sue-
cumbed to the action of the latex, but living encysted forms were
found several months after the inception of the cultures, those of
human Lamblia being the most resistant.

During the progress of the experiments it was observed that the

524

latex of certain plants exercised a remarkable preservative action
on the bacterial flora of the human intestinal tract. Such latex,
even in a very diluted form, would probably be a valuable
substitute for bouillon and other culture media.

Nakata (K.), Nakagima (T.),& TakimorTo (8.). Studies on Sugar
beet diseases and their control.—Bbull. Agric. Exper. Stat.
Chosen, vi, pp. 1-118, 8 pl., 1922. [Abs. in Japanese Journ.
of Bot., i, 8, p. 43, 1923.]

Since 1913 the writers have made a special study of the diseases
of sugar beet and their control in Korea. These include leaf spot
(Cercospora beticola), snake-eye disease (Phoma betae), sclerotial
disease (Sclerotiwm rolfsii), bacterial leaf spot (bacterium aptatum),
crown gall (Bacterium tumefaciens), ‘Mompa’ disease (Septobasi-
dium mompa), stem and root rot (Corticitwm vagum [solani)), Alter-
naria leaf spot (Alternaria sp.), white rot (Bacteriwm destructans),
black heart leaf spot (probably Colletotrichwm omnivorum), white
hollowed disease (Rhizoctonia sp.), and Physarum disease (P.
cinerewm).

The most serious of these diseases is leaf spot, which causes 20
per cent. loss of yield and 40 per cent. loss of sugar content. The
causal organism, C. beticola, remains viable for 16 months at room
temperature, for 5 months on the surface of the field, and for 8
months in the soil under winter conditions at Suwon (southern
Korea). The sclerotium-like bodies embedded in the host tissue
play the chief part in overwintering. The disease may be con-
trolled by spraying and seed disinfection.

The disease of leaves and roots caused by Phoma betae ranks
next to leaf spot in severity and is prevalent in sandy soil or
during dry seasons. The causal organism is disseminated on the
seed and the spores retain their vitality even after passing through
the alimentary canal of live stock. Seed treatment and rotation
of crops are effective in controlling the disease. Corticium vagum
affects the stems, roots, and leaves of the plants and may remain
viable for six months in the soil of Suwon. The removal of soil
round the crown of the roots to facilitate aeration, and sterilization
of the soil with formalin are recommended.

Sclerotium rolfsii is widely spread throughout ail regions of
Korea.

BRUNER (S. C.). Mosaic and other Cane diseases and pests in
Cuba.— Louisiana Planter, \xx, 22, pp. 452-455, 4 figs., 1928.

The symptoms of mosaic disease of sugar-cane are briefly
described and Brandes’ report of its transmission by Aphis maidis
[see this Revzew, ii, p. 381] confirmed as a result of the writer's
‘experiments in Cuba.

Generally speaking, very few systematic efforts are being made
to control the disease in Cuba, with the result that it is steadily
increasing, though less rapidly than in Porto Rico. Although
infection can be considerably reduced, when the percentage is not
too high, by the destruction of the diseased plants in a given field,
the method ultimately adopted in Cuba will probably be the use of
resistant and immune varieties. Under Cuban conditions the

525

Crystalina variety is highly resistant, although reports (not yet
verified) from Oriente state that the variety is heavily attacked.
Preliminary experiments with this variety carried out on the
typical red soil at the Experiment Station have shown that under
conditions where Yellow Caledonia, Morada, and Blanca varieties
break down severely and develop large cankers and stunted stalks,
the Crystalina variety bears practically no cankers during the
first year’s growth and there was no noticeable difference in the
size or appearance of healthy and infected stools, except for
the mottled condition of the leaves. An occasional stalk of
diseased Crystalina was found, showing a few very superficial
white cankers, so that possibly, under certain conditions, the
variety may be more susceptible than is usually the case.

In Central Soledad, where the disease was first observed in Cuba,
it is spreading very slowly and, according to a report dated May
1923, causing no appreciable damage.

The highly resistant Hawaiian variety, Badila, has been intro-
duced into Cuba, where it is giving excellent results. It compares
favourably with Crystalina in purity and in the percentage of
glucose and sucrose. It is being propagated at the Experiment
Station for distribution on a large scale.

Excellent yields have been obtained from the immune Kavangire
or Uba cane, amounting in Porto Rico to 81 tons per acre. In the
Argentine an average of seven crops of Uba cane is reported to have
yielded 34 times the tonnage of the ordinary Cinta or Rayada and
three times the quantity of sugar per acre. In Cuba the highest
yield in 1921 was 58-6 tons of cane and 8-54 tons of sugar per acre.
This refers to cane grown without irrigation or fertilizers. The
standard of purity in certain lots of the present year’s crop was also
extremely high, (91-92) [quotient of purity]. Uba is especially
valuable for planting in poor, exhausted soils where Crystalina
often has to be abandoned owing to its liability to deteriorate
under unsuitable conditions. Since 1919 cuttings of Uba eane have
been distributed to more than 230 agencies and individuals.

Other diseases of sugar-cane are of minor importance in Cuba.
Root rot, attributed to Marasmius sacchari and M. stenophyllus,
and black rot, caused by Melanconiwm sacchari, principally attack
injured or weakened canes. The latter fungus may also cause
considerable damage to over-ripe cane. Red rind disease (Colleto-
trichum falcatwm) and various leaf spot diseases due to Lepto-
sphaeria sacchari, Helminthosporium sacchari, Cercospora vaginae,
and C. kopket are common but not destructive, while Diplodia
cacaoicola |Botryodiplodia theobromae]|, Thielaviopsis paradowa,
Hypochnus sacchari, and Sclerotvwm rolfsii are relatively innocuous.

EARLE (F,S.). Experiences with mosaic disease. Uba found to
be immune in Cuba.—South African Sugar Jouwrn., vii, 5,
pp. 427-428, 1923.

During a recent visit to Cuba the writer was greatly impressed
by the rapid spread of mosaic disease of sugar-cane in the island.
Some fields in the Pinar del Rio province are infected to the extent
of 50 per cent., while in the Guantanamo district the disease is
also extremely severe. The yield in the latter locality has declined

526

by one half since last year, partly on account of the drought, but
also owing to the epidemic of mosaic. In spite of the wide pub-
licity given to the Porto Rico experiments in the control of the
disease [see this Review, i, p. 342 and also ii, pp. 88, 241], no
concerted plan for the adoption of similar measures has been
organized in Cuba, where the situation is becoming increasingly
serious.

Uba, Zwinga, Cayania 10, and some of the slender North Indian
varieties are immune from mosaic disease, and Crystalina is resis-
tant. With the last-named variety the losses from mosaic under
ordinary Cuban conditions vary between 20 and 50 per cent. Good
cultivation and the liberal application of nitrogenous fertilizers.
together with a plentiful rainfall, may keep the percentage of
infection down to the lower figure. Infected fields cannot be kept
in production for nearly so long a period as healthy ones, and this
strikes at the root of Cuba’s great advantage over most other cane-
growing countries—the capacity to produce many ratoon crops with-
out the expense of replanting the fields.

The use of healthy ‘seed’ and the roguing of partially in-
fected fields (where the incidence of disease does not exceed
25 to 30 per cent.) will do much to prevent the spread of mosaic.

KuyYPER (J.). Het Wortelrot op Java, speciaal in verband met de
Rietsoort EK 28. [Root rot in Java, especially in connexion
with the Cane variety EK 28.]— Meded. Proefstat. Java
Suikerind., 4, pp. 117-161, 2 diag., 1923.

Towards the end of 1921 root rot of sugar-cane was observed to
be causing considerable damage in Java, especially on the variety
EK 28.

The roots of affected plants were frequently stunted, crooked,
or swollen, the shoots small and sickly, and the leaves yellow,
crinkled, and covered with irregular withered spots. Sections
through the base of the diseased shoots revealed grey, red, or
reddish-brown discoloration of the tissues, which were slightly
spongy in texture and sometimes dead. The growing points were
more vividly coloured than those of healthy cane and the buds
had a tendency to run out.

The etiology of the disease is still rather obscure. There appear to
be two distinct kinds of root rot; the so-called ‘anaerobic’ root rot,
which occurs chiefly on heavy, badly aerated soils saturated with
stagnant water, and ‘dry’ root rot, which is primarily an affection
of the setts, due to an insufticiency of water in the soil.

There is no evidence of a parasite being implicated, and whilst
the similarity of the disease to grey speck of oats [see this Review,
i, p. 417 and ii, p. 403] suggests that soil alkalinity may be the
cause, experiments on this point have not yet been carried out.

Biennial rotation greatly increases the incidence of root rot; at
least three years should elapse between one crop of sugar-cane and
the next.

Exhaustive evidence is adduced to prove that there has been no
increase in the percentage incidence of root disease in Java. EK 28
has been susceptible from the very first, but even allowing for
a certain amount of disease it shows no sign of ‘degeneration’ and

527

there can be no justification for a reduction of the area under this
prolific and valuable variety.

Bertus (L. 8.). Grey blight of Tea and Coco-nut: a comparative
study. Trop. Agric., lx, 2, pp. 109-112, 3 pl., 1923.

A study of the Pestalozzia spp. causing grey blight of tea and coco-
nut leaves was made to ascertain the identity of the species affect-
ing each host [see this Review i, p. 413]. Typical Pestalozzia
spores on tea and coco-nut are fusiform, divided by four septa into
a row of five cells of which the three central are light brown and
the terminal hyaline. The apical hyaline cell is crested with one
to four hyaline cilia and to the lower hyaline cell is usually
attached the stalk on which the spore is borne. Abnormalities
occur in the dimensions of the spores and in the number of coloured
cells.

The species of Pestalozzia occurring on coco-nut was cultured on
maize meal, French bean, and quaker oats agar. In all three
media the chief feature of growth was the aggregation of the
hyphae into white, later pinkish tufts, from the centre of which
arose black pustules of spores. In the French bean and oatmeal
media a stroma was formed, while in the maize meal a pseudostroma
was present. The spores originated in distinct pycnidia of diverse
shapes and sizes, consisting of a yellowish, pseudoparenchymatous
wall, with no ostiole, the spores being liberated by a rupture of
the wall at any point. They occurred singly or in groups, but
a few spherical pycnidia were found embedded in the stroma or
pseudostroma. The average dimensions of the spores on leaves in
nature are 20-2 by 5-7 «7; on French bean agar 18-7 by 5-4; on
oatmeal 18-8 by 5-5 and on maize meal 18-5 by 5-7 y respectively.
The cilia were generally 2 to 5 win length, occasionally 10 to 12 p;
the stalk, when present, 1 to 3y, rarely 4 to5y. In culture the
cilia are shorter than in nature, and do not bear knobs at
their ends.

Spores of the Pesta/ozzia found on tea were grown on the same
media as above. A rich, flocculent growth of aerial hyphae ulti-
mately developed into a thick, heavy, compact felt, spread over the
medium, no tufts of hyphae being formed. A characteristic feature
was the production of spores on loose hyphae. The growths on
three different media are described in detail, a stroma or pseudo-
stroma being formed on which pycnidia were mainly found. The
latter varied in shape and dimensions and were enclosed by a
pseudoparenchymatous wall, from which the spores were liberated
at any part, but frequently the rupture occurred at the base. The
average dimensions of the spores on tea leaves in nature are 25-6
by 6 to 7; on French bean agar 27-3 by 6-7 ~; on oatmeal 27-4
by 6-9 yw, and on maize 26-6 by 6-8y. On all the media the cilia,
which varied in number between two and four, were very long (up
to 40 yz), and mostly knobbed. The length of the stalk varied from
3 to 10 pz.

The morphological and cultural differences between the two
species are considered to justify the retention of the distinction
which obtains at present. The Ceylon species on the coco-nut leaf
is Pestalozzia palmarum Cooke and that on tea P. theae Sawada.

528

GaRD (M.). L’apoplexie de la Vigne. Les moyens de la combattre
et d’y remédier. [Apoplexy of the Vine. The means of
controlling and curing it.]—Rev. de Vitic., lviii, 1509, pp. 399-
401, 1928.

Apoplexy of the vine [caused by the fungus Fomes igniarius :
see this Review, i, p. 416, and ii, p. 437] may be effectually controlled
by the application, during the winter, of arsenite of soda made up
ot 30 kg. carbonate of soda and 380 kg. of arsenious acid, dissolved
in 60 1. of boiling water. Between 90 and 100 vines can be
treated with 10 1. of the solution at an average cost of 1 to 1-5 fr.
[about 3d, to 44d.], exclusive of the price of labour. The vines
may either be sprayed or painted with the solution.

Directions are also given for the excision of the diseased parts
and for a special system of grafting to be practised on infected
vines.

McGinty (R. A.). Head Lettuce in Colorado.—Colorado Agric.
Exper. Stat. Bull. 283, 26 pp., 7 figs., 2 diag., 1923.

The most serious disease of lettuce in Colorado is tip burn, which
causes a blackening of the edges of the inner leaves and the partial
or total decay of the interior of the head. The disease appears to
be of a physiological nature, and in the Imperial Valley it is corre-
lated with excessive alkalinity of the soil. It is most prevalent
when bright, hot weather succeeds a rainy period, and soils with
an inadequate water supply are more favourable to the disease
than those of high water-holding capacity. During storage or
transit a slimy soft rot will often start in the tissues weakened by
tip burn, causing total loss of the affected head. Even slightly
diseased heads invariably develop a disagreeable bitter flavour.

The best remedies for tip burn are good seed and strict attention
to cultural measures, with frequent light irrigations during hot,
dry spells. Attempts to develop a resistant strain of lettuce are in
progress.

The Uganda Customs (Amalgamation) Ordinance, 1918, Notices
5th May, 1923.—Official Gazette, Entebbe, p. 294, 15th May,
1923.

The importation into Uganda of sugar-cane plants or parts
thereof, except under a written permit previously obtained from
the Director of Agriculture, is prohibited.

Amendments to the Regulations under the Destructive Insect
and Pest Act.—Canada Dept. Agric. Exper. Farms Branch
Div. Bot., 2 pp., 19238.

Amendment No. 20 (No. 3 of 1923) to the Regulations prohibiting
the importation of certain species of Berberis into Canada provides
for the addition of European buckthorn (Rhamnus cathartica) to
the list of prohibited plants on account of its being a host of the
crown rust of oats [Puccinia coronata).

Amendment No. 21 (No. 4 of 1923) provides for the addition of
R. cathartica to the list of plants excluded from admission to the
Prairie Provinces (Manitoba, Saskatchewan, and Alberta), and for
its extermination, without compensation, within the aforesaid
Provinces.

a a

COO EE =< <=

IMPERIAL BUREAU OF MYCOLOGY

REVIEW

OF

ae tin D MY ¢OoLOGE

Vou. Il DECEMBER 1923

NICOLAISEN. Solbar gegen die Braunfleckenkrankheit der Tomaten.
{Solbar as a remedy for the brown spot disease of Toma-
toes. |—Deutsche Obst- und Gemiisebauzeit., |xix, 19, pp. 147-
148, 1923.

The brown spot disease of tomato leaves and stems, caused by the
fungus Cladosporium fuscum [C. fulvwm ?], was very severe in the
spring of 1922 on greenhouse plants of the Lucullus variety at
Calbe [Saxony]. The plants were attacked quite suddenly and had
a sun-scorched appearance. Four days after the affected plants
and the surrounding soil were sprayed with 2 per cent. solbar;
they recovered completely, and at the end of a fortnight they were
equal to their healthy neighbours in size and vigour.

S. (G. N.). Pine branch twist. A fungus disease on Pine,
Melampsora pinitorqua.—Cyprus Agric. Journ., xviii, 1, p. 19,
1923.

Young pines [Pinus] up to twelve years of age have frequently
been known to be attacked by a fungus, Melampsora pinitorqua,
which interferes seriously with their growth, and recently two cases
have been observed in the Paphos forest (Cyprus) although many
other instances probably exist. The leading shoot bends over in the
shape of a hook and usually dies, and the lateral shoots which
subsequently grow up to take the place of the dead leader become
infected in their turn. Occasionally the leading shoot recovers,
but it is safer to cut it off below the diseased part. Young trees
killed by the fungus or diseased parts excised from living trees
should be burnt.

The reason for the twisting of the shoots is that the attacked
side does not grow at the diseased spot while the other side grows
normally and so causes the twig to bend over.

Troup (R. S.). The Cedar fungus.— Report on Forestry in Kenya
Colony, pp. 25-26, 1922.
The East African cedar [Juniperus procera] is attacked by a
wood rot fungus, Fomes juniperinus [sec. Lloyd F. demidoffic]
M

530

which also occurs on junipers in the United States. In Kenya it
causes enormous losses in timber production, attacking the heart-
wood of standing trees. As a rule there is no external sign of
attack, the presence of the disease being revealed only when the
tree is cut open. Occasionally, however, the perennial ungulate
fructifications may be found on the side of the tree, nearly always
where a branch has been broken off. In its early stages the
disease is characterized by the presence of small pockets of whitish,
decaying tissue, and later by large, irregular hollows containing
masses of brownish-yellow, felty mycelium. The tissues in the
wood are disintegrated and permeated by the hyphae of the
fungus.

To a large extent the disease may be controlled by the following
preventive measures: (@) protection from fire and other injury ;
(6) cultivation in close crops in suitable permanent mixtures in
order to effect natural pruning of the branches before they have
begun to form heartwood; (c) periodical removal in thinnings of
all stems with broken branches or wounds in which the heartwood
is exposed.

CHAVASTELON. Sur un traitement pratique et efficace des plaies
des arbres. [On a practical and efficacious treatment of the
wounds of trees.|—Comptes rendus Acad. d Agric. de France,
ix, 17, pp. 474-476, 1923.

An efficient wound dressing, which will encourage thorough
healing and at the same time preserve the exposed wood, is made as
follows: hot solutions of potassium or sodium bichromate (6 per
cent.) and copper sulphate (6 per cent.) are allowed to cool and
then mixed. The resulting compound consists of undecomposed
copper sulphate, potassium or sodium sulphate, and bichromate of
copper (Cr,0,.Cu0.2H,0). The object of mixing the solutions cold
is to prevent the formation of CrO,.Cu2H 20. a reddish-brown
chromate of copper which diminishes the strength of the
solution.

The immediate effect of the application isa slight browning of the
wood, any bichromate oxidizing and coagulating in the presence of
the albuminoids and gums. The bichromate of copper, which is
only slightly soluble, closes the pores and forms a durable reserve
of chromic acid which is liberated by progressive dissociation, under
the influence of the sap or of exterior water, of the chromate of
copper into basic chromates. This weak concentration of chromic
acid, while acting as a complete disinfectant, has no toxic effect on
the plant and does not interfere in any way with the functions of
the healing zone formed round the wound. Furthermore, the
albuminoid substances of the exposed cells, coagulated and im-
mobilized by the bichromates, contribute to the preservative
action by completing the decay-proof crust formed by the chromate
of copper.

Vertical and horizontal incisions on a variety of fruit trees and
walnuts have been treated by the above method with complete
success for the last seven years. Applied to the vine at or before
the unfolding of the buds the same solution has proved highly
beneficial, and also effectively controls fungous diseases, especially

“Se

531

[downy] mildew [Plasmopara viticola] and Oidiwm [Uncinula
necator |. For the latter purpose the solution may be reduced to
half the strength recommended above.

Weir (J. R.). The effect of broadcast burning of sale areas on
the growth of cull-producing fungi.—Journ. of Forestry, xxi,
- 2, pp. 183-184, 1923.

The most important cull-producing fungi founf on stumps and
slash on sale areas in Idaho and Montana after the merchantable
timber is removed, and the ground burnt over, are as follows: Poria
subacida (form), chiefly on stumps and cull butts of spruce and white
pine; not fruiting. P. weiriz, completely destroying all cull butts
of western red cedar [Thuja plicata] and in the duff [dead leaves,
broken branches, &c., accumulated in a forest] around the stumps.
Polyporus schweinitzi, chiefly on stumps, cull butts, and in the duff
of Douglas fir, larch, white pine, spruce, and in a lesser degree on
other species. The fungus is more apt to reappear from infected
roots at some distance from the stump than at the stump itself; the
root crotches tend to hold the fire and the mycelium is destroyed.
Trametes pint on stumps, cull logs, and large branches of white
pine, larch, Douglas fir, spruce, and other species; not fruiting.
Fomes roseus on stump cull logs of Douglas fir; not cesta Bs
laricis on stump cull logs and tops of larch, yellow pine [Pinus
ponderosa |, and Douglas fir ; rarely fruiting from the charred ends of
large cull butts. /. pinicola on stumps and cull logs of grand fir
[Abies grandis] and larch ; fruiting occasionally. -This fungus is the
least important of the group. F. annosus entirely destroying stump
cull butts of grand fir, larch, and white pine. Echinodontiwm tinc-
toriwm on cull logs of grand fir, lowland and mountain hemlock
[Tsuga heterophylla and T. mertensiana Sargent]; not observed
to produce sporophores. Armillaria mellea on reproduction chiefly
of Douglas tir, larch, and white pine, also mature trees attacking
roots and débris in the duff; rarely appearing after the fire.

The majority of the cull fungi fruit with difficulty in the open
exposed conditions of a clean cut area except on infected standing
trees. Only when there is a large amount of slash and vegetation
reproducing the moisture and shade conditions of the closed forest
do sporophores appear in excessive numbers on the débris of a sale
area. Such conditions may be expected to obtain in the white pine
belt of Idaho. The destruction of the vegetation and the smaller
kinds of slash and the charring of the stumps and logs prevents
a return to the closed forest conditions.

Charred stumps and logs are rarely re-infected by the cull fungi
of the living tree. Such sporophores as do appear must in most
cases be produced by the living mycelium in the heartwood that did
not succumb to the heat of the fire.

True saprophytes, such as Trametes odorata, Lenzites suepiaria,
Polystictus abietinus, Poria selecta, P. carbonaria, and various
species of Thelephoraceae regularly infect and destroy the inner
wood of charred slash, entrance being effected through the season
checks. The evidence shows that from the standpoint of a
diminution of the sources of infection to standing timber broad-
east burning may, in certain cases, be regarded as good silviculture.

532

EastHAM (J. W.). Sweet Potato diseases.— Agric. Journ. Brit.
Columbia, viii, 4, pp. 83 and 86, 1928.

The writer emphasizes the importance of preventing the intro-
duction into British Columbia of black rot (Sphaeronema fimbriata)
and other diseases of the sweet potato. Short of placing a total
embargo on the importation of sweet potatoes, which would be
a very severe handicap to trade, the only measures which can be
adopted for the protection of British Columbian crops are the use
of certified seed from healthy plants, the rejection of any roots
showing signs of disease, and the disinfection of seed, before
planting, with 1 oz. corrosive sublimate to 6} imperial gallons of
water. Fresh soil should be used every year for the hot-bed, the
woodwork being previously sterilized by swabbing with 2 lb. of
copper sulphate or 3 lb. formalin to 40 galls. of water.

DirFLoTH (P.). Les ennemis de la Vigne. Galles et cryptogames.
[Enemies of the Vine: galls and cryptogams.|—La Vie agric.,
XX, 22, pp. 367-370, 4 figs., 1923.

The following fungous diseases of the vine [in France] are briefly
described and appropriate measures for their control recommended :
black rot, caused by Guignardia bidwellii; grey rot [Botrytis
cinerea]; powdery mildew (Uncinula necator) ; anthracnose (Spha-
celoma ampelinum) ; canker (Cryptosporella viticola and Glomerellu
congulata). One bacterial disease (crown gall, caused by Bacteriwm
tumefaciens) is also briefly noticed.

STIEGLER (A.). Der echte Meltau (Oidium tuckeri) und der falsche
Meltau (Peronospora viticola) sowie deren Bekampfung.
[Mildew (Oidiwm tuckeri) and downy mildew (Peronospora
viticola) and their control. |— Allg. Weinzeit, xl., 4, pp. 51-52,
1923.

The first application of sulphur for the prevention of mildew
(Oidium tuckeri) [Uncinula necator| should be given as soon as
the fruit is set and the second towards the close of the blossoming.
Further applications need only be given if there is reason to fear
a severe outbreak of the disease. For the controk of downy
mildew (Peronospora [Plasmopara] viticola) a 1-5 per cent.
Bordeaux mixture or Bosna copper paste should be given just
before, and a second spray (1-75 to 2 per cent.) immediately after,
flowering. One or two more applications at 1-5 per cent. should
be given if the weather conditions appear favourable for the out-
break of the disease. This treatment will also be found useful in
the control of ‘ rotbrenner’ [Pseudopeziza tracheiphila], which has
caused much damage of recent years in the dry, stony soils of
Styria [ Austria ].

The author particularly recommends for the spraying operations
the ‘Flick’ apparatus, the construction and use of which is
described.

HENGL (F.). Vergleichende Versuche gegen verschiedene Reben-
schadlinge. [Comparative experiments in the control of
various Vine pests. |—Allg. Weinzeit., xl, 2, p. 5, 1928.

The continuation is reported of the regular annual experiments

533

in the control of vine pests carried out by the Vienna Plant
Protection Institute and the Association of Austrian Vinegrowers.
Owing to the abnormally dry weather conditions during the 1922
season, fungous pests were very little in evidence. The results of
the tests may be summarized as follows: I. Experiments in the
suppression of ‘roter Brenner’ (Pseudopeziza tracheiphila) on
Veltliner grapes. Satisfactory results were obtained by the use of
alkaline Bordeaux mixture, ‘Bosna’ copper paste, ‘Bosna B’
(copper zinc paste), and kurtakol. II. Downy mildew (Peronospora
[Plasmopara| viticola). Good results were secured by three appli-
cations, on 6th June, 20th June, and 14th July respectively, with
alkaline Bordeaux mixture, Bosna, Bosna B, Caffaro-Bosna, cuprol-
pasta, and kurtakol. JIT. Mildew (Oidium tuckeri). A number of
wet and dry fungicides were tried against this disease but owing
to the mildness of the mildew attack their efficacy could not be
gauged.

RECKENDORFER (F.). Die Rotbrennerbekampfung. [The control
of ‘rotbrenner *.|— Allg. Weinzeit., xl, 4, pp. 52-53, 1923.

The ‘rotbrenner’ disease [caused by Pseudopeziza tracheiphila]
has for some years past been very prevalent in all parts of Austria
{see also this Review, ii, p. 302] where the red, red-white, and
brown Veltliner vines are extensively cultivated, the red-white
Veltliner variety being especially susceptible.

The fungus overwinters on the fallen leaves, where it produces
ascospores in the spring. The young leaves nearest the ground are
infected by the ascospores, the affected parts turning red (in black
varieties) or whitish-yellow (in white varieties) and withering. In
severe cases defoliation ensues and the fruit is also attacked. The
development of the roots is arrested, the wood matures badly,
and the fruit fails to ripen. The disease also affects the next year’s
growth.

Treatment with 2 per cent. Bordeaux mixture or Bosna copper
paste is recommended, beginning about the middle of May.

Taytor (W. H.). Vine culture under glass. Diseases and pests
of the Vine.— New Zealand Journ. of Agric., xxvi, 3, pp, 172-
Bes, 1923,

Powdery mildew (Uncinula necator) attacks the vine during the
early stages of growth and also in the autumn. The disease can
be controlled by a dusting of dry flowers of sulphur applied
immediately the first symptoms appear. Should an epidemic occur
during the stoning period, however, more drastic measures must be
adopted. A good handful of sulphur should be mixed with
sufficient milk to make a thin paste, and diluted with about 2 galls.
of tepid water. All the vines and walls of the house should be
syringed with the solution about an hour before the sun leaves the
roof. The top ventilator should be closed during the treatment
and reopened before daybreak in order to dry the vines before the
sun reaches them. On the evening of the next day but one, the
vines should be syringed with clean tepid water.

The germination of the spores of U. necator is favoured by
excessive cold on tender vegetable surfaces. The sun in the early

534

morning, or more frequently newly admitted air, causes sudden
evaporation of the moisture collected during the night, lowering
the temperature and thereby producing conditions favourable to
infection. Hence the ventilators should be opened early before the
sun shines and care taken to avoid draughts.

Vine Sclerotinia (S. fuckeliana) oceurs only in a very damp
atmosphere and may be prevented by proper ventilation. The
mould form of the disease can be checked by spraying with liver
of sulphur at the rate of 4 oz. per gall. of water.

Grape spot (Gloeosporium fructigenum) is usually restricted to
thin-skinned white grapes. Spraying is not practicable and the
only remedy is to increase the ventilation and prevent an accumula-
tion of moisture during the night.

Shanking or withering of the pedicels of the berries and stems
of the bunches, which results in sour and uneatable fruit, is due to
an imperfect balance between the root and top. An excess of
organic matter in the soil induces the formation of soft, spongy
roots and a correspondingly excessive growth of soft foliage early
in the season. Later the death of the spongy roots leaves the vines
with insufficient roots to feed the superfluous foliage. The remedy
for this trouble is to restrict the activity of the roots by rigid and
timely suppression of early lateral growth. Cold and acid sub-
soils and very thin leaves are predisposing causes of shanking.

Scalding, due either to the direct action of the sun’s rays or to
sudden variations in temperature, sometimes causes serious losses
during the stoning period. A frequent cause of scalding is an
unduly wide range between day and night temperatures, combined
with atmospheric moisture. Damping down should therefore be
reduced to a minimum and a little top air left on all night, being
increased in the very early morning to prevent a sudden rise of
temperature. During the day the temperature should be kept as
low as is consistent with proper ventilation.

Warted leaves are generally found on vines growing in rich soil
in the warmer districts. ‘The damage is done by a sudden evapora-
tion of moisture from the gross foliage, usually caused by a current
of cold air.

Aerial roots may be due to the defective action of roots in cold
soil, or to a warm or moist atmosphere combined with a lack of
proper ventilation due perhaps to poor drainage.

PiunkKETT (O. A.), Youne (P. A.), & Ryan (RutH W.). A syste-
matic presentation of new genera of fungi.—Z'rans. Amer.
Microscop. Soc. xlii, 1, pp. 43-65, 1923.

The new families and genera of fungi described since Volume xxii
of Saccardo’s Sylloge Fungorum was compiled, are here assembled
from all the available literature and presented in a concise, classi-
fied form with the reference accompanying each new name.

As far as is known, there has been no previous compilation of
the new genera of fungi described since 1910, and its absence has
necessitated a constant searching of extensive and scattered litera-
ture for any special type required. This paper will be of value to
mycologists who require a survey of the systematic work carried out
during the last twelve years. ‘There are, however, many omissions.

535

The list of genera covers about 7,000 new species of fungi. It is
an abbreviation of a catalogue entered on cards in taxonomic order,
and giving the citation, classification, name of the genus, and
generally the host of the fungus. Of the new species 800 belong
to the Sphaerioidaceae, 700 to the Agaricaceae, 300 to the Puc-
ciniaceae, 200 to the Dematiaceae, 200 to the Microthyriaceae, 200
to the Pleosporaceae, 150 to the Mycosphaerellaceae, and 100 to
each of the following families: Dothideaceae, Hypocreaceae,
Melanconiaceae, Moniliaceae, Polyporaceae, Sphaeriaceae, Thele-
phoraceae, Tuberculariaceae, and Valsaceae.

A bibliography of the publications consulted for the work, com-
prising 89 titles, is appended.

Actpaxanckan Craniua Sauutet Pacrenuii or Bpegureneii.—Oraet
3a roq Oxt. 1921—Oxr. 1922 r. [Astrakhan Plant Pro-
tection Station—Report for the year Oct. 1921-Oct. 1922],
40 pp., 1922. [Rec’d. 1923.]

The year under review was marked by continued difficulties
arising mainly from financial stress, which greatly hindered the
scientific research work of the Station. The latter was, however,
able to extend its activity by the creation of three branch offices
and by establishing an instructor in phytopathology in each of
nine districts into which the province was divided. Considerable
additions were also made to the collections and library of the
Station.

Most noticeable among the diseases of cultivated plants during
the year were: black rot canker of apple (Sphaeropsis malorum),
which killed a large number of trees in the best orchard districts
and was also occasionally found on pear trees; apple and pear scab
(Fusicladium dendriticum) ay F. pirinum|, apple leaf spot
(Phyllosticta briardi), pear leaf spot (Septoria piricola), cherry leaf
spot (Cercospora cerasella), and plum leaf spot (C. circunscissa),
peach leaf curl (Exoascus deformans), plum ‘scorch’ (Polystegminu
rubra), and pear rust (Gymnosporangium sabinae). Corn crops
suffered heavily, especially in irrigated fields, from various kinds of
smut and rust. A new functional disease, strongly resembling
mosaic, appeared on potatoes, greatly reducing the crops, and
attacking also, but more rarely, tomatoes and eggplants (Solanwm
melongena) which perished in a few days. In some cases a rotting
of potato tubers was observed in the soil, but the cause has not yet
been determined. Vegetable marrows were heavily attacked by the
semi-saprophyte Sporidesmium mucosum var. plwriseptatum. The
station recorded for the first time the appearance of Oidiwm
tuckeri on the vine in some districts, which caused very appreciable
losses.

Bore (P.). Report of the Plant Pathologist 1921-1922.— Malta
Govt. Gaz. Swppt. xxi, pp. 278-280, 1923.

Potato blight (Phytophthora infestans) appeared early in
November on the winter crop of potatoes and caused a heavy
reduction in the yield, the weather being very favourable for its
development. The first outbreaks on the spring crop were also

536

rather virulent, but a serious epidemic was averted by extensive
spraying and also by the continuation of dry weather.

Owing to the protracted spell of hot, dry weather in March
[1922] downy mildew of the vine [Plasmopara viticola| did not
develop to any great extent, but spraying with normal Bordeaux
mixture was carried out on a large seale as a precautionary
measure. The treatment of Oidiwm |Uneinula necator) has now
become a matter of routine in most vineyards. The disease known
as ‘roncet’, the etiology of which is obscure, appeared on many
vines of the Rupestris du Lot variety in the American vine
nurseries at Gozo and elsewhere. The only known remedy is the
removal of infected plants before the second year after the
appearance of the disease.

Departmental Activities: Botany.—Journ. Dept. Agric. S. Africa,
vi, 5, p. 881, 1923.

Leptothyrium pomi, the cause of ‘sooty blotch’ and ‘fly speck ’
in apples, has been identified on apples from the Transkei and
Natal, this being its first recorded appearance in South Africa.
Whilst the injury does not penetrate very far, the unsightly
appearance of affected fruit impairs its market value, and badly
diseased apples often look shrivelled or wizened. The dark
coloured blotches on the surface of the fruit are irregular in outline
but tending to be circular, and they may be so numerous that the
fruit appears as if covered with soot. ‘Fly speck’ is another aspect
of the same disease. In this case groups of six to one hundred
black, shiny dots, which appear on the surface of the apple, recall
fly-blown specks, hence the name. Damp situations and abundant
rain in the summer favour the development of the fungus, which
can be controlled by several applications of a lime-sulphur spray,
as in the treatment for apple scab.

‘ Vrotpootje ’ of wheat is still being studied by the Department.
Particulars obtained from diverse sources would seem to indicate
that more than one disease is known by this name. Thus, a case
from the Koeberg District has been diagnosed as a foot rot, due
probably to a species of Fusariwm, while from another region the
disease resembles the ‘ take-all’ and ‘ whitehead’ disease (Ophiobolus
caricett) known in Europe and other parts of the world.

Dickson (J. G.). Influence of soil temperature and moisture on
the development of the seedling-blight of Wheat and Corn
caused by Gibberella saubinetii.—Journ. Agric. Res., xxiii,
11, pp. 837-869, 6 pl. (2 col.), 15 graphs, 1923.

Gibberella saubinetit may attack wheat and maize seedlings in
varying degrees of intensity, resulting («) in blight before emerging
from the soil, with a consequent reduction in stand; (b) in a
yellowing and wilting of the seedling after it emerges; and (c) in
a stunting of the seedling owing to the enfeeblement of the root
system. In both wheat and maize the invaded tissues turn reddish-
brown to carmine red, according to environmental conditions. The
chief difference between the symptoms of. the disease on the two
hosts is the more definite character of the lesions on the larger

537

stems and roots of maize. In both plants the period of severe
infection is usually restricted to the seedling stage. Seedling blight
develops from two chief sources; scabbed or infected seed and
infested soil. The mycelium of the fungus hibernates in or on the
scabbed kernels of wheat, many of which show no marked external
symptom of disease before sowing, and also in the seed of maize.
The organism develops as a saprophyte on decaying crop refuse
near the surface of the soil and assumes a parasitic character only
when the seedlings are weakened by unfavourable conditions.

The results of pure culture experiments, the technique of which
is fully described, showed that the parasite functions normally over
a fairly wide range of temperature, namely, from 3° to 32°C. The
optimum temperature for spore germination, vegetative develop-
ment, and sporulation was found to be about 24° on unacidified and
28° on acidified media.

It was further shown by comparative experiments in the develop-
ment of wheat and maize at different soil temperatures that the
former is favoured at all stages of growth by a low temperature
(16° to 20° C. for spring wheat and 12° to 16° for winter varieties),
and the latter by a high one (24° to 28°C.).

The temperature of the soil is undoubtedly the most important
single factor determining the extent of seedling blight. The most
favourable soil temperature for the infection of wheat was found to
range from 12° to 28° C., while the corresponding figures for maize
infection were 8° to 20°C.

It was also shown that low soil moistures favour the infection of
wheat seedlings at all temperatures, and at low temperatures may
be the factor determining infection. Thus at 8°C. soil temperature,
72 per cent. of the seedlings grown in soils at 30 per cent. of their
moisture-holding capacity were blighted,and 44 per cent. of those
grown at 45 per cent. moisture, whereas at 60 per cent, soil moisture
no blight occurred.

In order to check the results obtained under greenhouse con-
ditions of the effect of temperature and moisture on infection,
a series of periodic field sowings were made at Wisconsin during
the spring and autumn of 1920 and the spring of 1921. It was
thought that such trials might point towards possible remedial
measures against this and similar diseases. The results under field
conditions corresponded with those obtained in greenhouse tests.
Sowing when the soil is cool, that is, spring wheat at the earliest
safe date in the spring and winter wheat at the latest safe date
in the autumn, reduces seedling blight [see this Review, i, p. 168}.

Maize, on the other hand, should be sown when the soil is warm,
at the latest safe date in the spring. The critical soil temperature
for the seedling blight of wheat is about 12°C, as determined both
in constant soil temperature tanks and in the field, where the
temperature was estimated by the mean daily field soil temperature,
the corresponding figure for maize being 20° to 24° under both
greenhouse and field conditions. Mean soil temperatures for
periods of considerable duration are more influential as factors
in the production of seedling blight and similar diseases than
brief extremes of soil temperature. The influence of environ-
mental factors on the hosts appears to be the fundamental cause of

M2

538

susceptibility to the disease, the seedlings becoming susceptible
when they are unable to respond favourably to the environment.
A bibliography of 34 titles is appended.

Drecer (C.). Praktische Erfahrungen eines Ziichters mit der
Bekaimpfung von Pflanzenkrankheiten, [The practical ex-
periences of a breeder in the control of plant diseases. |—
Weiner landw. Zeit., \xxiii, 25-26, pp. 102-104, 1923.

After many years’ experience in the cultivation of cereals, the
writer recommends the control of diseases by selection only when
the disease cannot be more speedily and effectually combated by
mechanical or chemical treatment. Yellow rust of wheat (Puccinia
glumarum) has not yet been adequately controlled by mechanical
or chemical means, and the same applies to brown rust of wheat
and rye (Puccinia triticinu and P. dispersa) and to barley leaf spot
(Helminthosporium teres). With the exception of the first-named,
however, these diseases do not cause sufficient damage [in Austria]
to justify any great expenditure of time and labour on plans for
their control.

The hot water treatment of loose smuts of wheat (Ustilago
[tritici]), barley (U. [nuda]), and oats (U. [avenae]) is described at
length. As regards loose smut of barley, the seed may safely be
heated to a temperature of 53° to 53-5°C. for ten minutes after
a preliminary soaking of eight hours at a normal temperature,
without any risk of reduced germination. It has frequently been
stated that the thick-eared or ‘erectum’ varieties of barley are
immune from loose smut, but the writer has not found this to be
the case. For the control of loose smut of wheat the seed should
be heated to a temperature of 52° for ten minutes (54° for summer
wheats). Both for barley and wheat the eight hours’ presoaking is
essential to the success of the treatment. Wheat is considerably
more difficult to treat than barley, owing to the variations in the
time of treatment required.

In the case of loose smut of oats no preliminary soaking is
required, as the fungus is outside the seed. The writer has secured
excellent results for many years by a preliminary heating at 45°
followed by hot water treatment for ten minutes at 56°. Stripe
disease of barley (Helminthosporiwm gramineum), the incidence of
which has greatly increased of recent years, was completely
controlled by immersion of the seed in 375 gm. of uspulun per hl.
of water for one hour. The seed had previously been treated
with hot water, but this process alone does not give adequate
control.

Bunt of wheat (Tidletia tritici) cannot be effectively controlled by
the hot water treatment. The writer tested a number of fungicides
and obtained the best results by immersion of the seed in 500 gm.
40 per cent. formaldehyde per hl. of water for fifteen minutes. It is
essential that the spore balls should be removed by a preliminary
immersion in water. The writer has observed that animals are
frequently fed on smutted grain, with the result that the infection
is perpetuated in manure. The organism is evidently capable of
leading a saprophytic existence in the soil for at least two years,
since wheat sown by the writer was found to be heavily infected,

539

in spite of treatment with formalin, presumably by the spores of
smutted wheat grown in the same field for experimental purposes
two years earlier.

Tower (W, V.). Citrus scab.—Porto Rico Agric. Exper. Stat.
Agric. Exten. Note 53. [Reprinted in Trop. Agric., lx, 4, pp.
224-226, 1923].

Scab [see this Review, ii, p. 864] is the most severe disease of
citrus in Porto Rico. During the early years of the industry only
young trees were attacked, but at present many valuable old trees
are producing inferior fruit as a result of the disease.

The results of the first season’s co-operative spraying experiments
on a large estate are very encouraging. The weather was ex-
ceptionally wet and the blooming period much prolonged. Four
applications of Bordeaux oil [see this Review, 11, pp. 363, 364] were
given to 3,000 trees on 29th December, 27th January, 13th
February, and 9th March respectively. The results were as
follows: clean fruit 94-4 per cent.; trace of scab 5:2 per cent.;
slightly scabby 0-4 per cent. Check trees in one of the worst
infected groves showed only 10 per cent. clean fruit. Sprayed
trees in this grove showed 90-6 per cent. clean fruit. Another
grove was divided into three sections, one part was sprayed four
times, another twice, and the third left as control. The percentages
of clean fruit were 91-2, 83-9, and 24-5. Results similar to the
above were obtained in other groves.

The author issues a warning with regard to scale insects,
however, as the beneficial fungi will be killed and spraying against
scale insects may be counted upon as necessary.

Recent tests with oil emulsion have been made at the Experiment
Station on grapefruit trees with fruit six months old, the solution
being used at 1-5, 2, 2-5, and 3 per cent. strengths. There was no
defoliation or injury to the fruit. In all the tests with 3-4—50
Bordeaux plus 0-5 per cent. of oil there was a slight burning of the
young shoots but no injury to open blossoms or small fruit.

Details regarding convenient arrangements for carrying out the
spraying are added.

Fawcett (H.S.). Gummosis of Citrus.—Journ. Agric. Res., xxiv,
3, pp. 191-282, 8 pl., 1923.

Pythiacystis gummosis, which first attracted attention in the
Azores in 1834 and subsequently spread to most other citrus-
growing countries, is the most widespread and destructive of
citrus gum diseases in California. On the highly susceptible com-
mon lemon (Citrus limonia) the disease is characterized by copious
exudations of gum and large dead areas of bark on the trunk and
main roots, followed by yellowing and dropping of leaves. On
sweet orange (CU. sinensis) and other semi-resistant forms the dead
patches are smaller. The gum may arise not only from the margin
of the infected area but also from a large contiguous, outer, non-
invaded zone. In the invaded area of the bark the- tissues are
coloured mineral brown to burnt umber or fawn, and the same dis-
colorations are found usually extending about 2 to 5 mm. into the
outer layers of the wood. In the outer gummous zone the cambium

540

is chamois to yellow-ochre in colour. Gum pockets, 2-5 to 5 em, in
longest axis, are frequently formed, the clear, watery gum harden-
ing as it comes to the surface and turning chestnut-coloured. It
has been shown by experiments that the disease is readily trans-
missible to healthy trees by inoculation with fragments of bark
tissue cut from the advancing margins of destroyed regions, but
not by tissue from the outer gummous zones or by old dead tissue.
Cultural tests demonstrated that live mycelium of P. citrophthora,
the causal organism of lemon brown rot, was present in the narrow
band or fringe at the advancing edges of the invaded zone. Else-
where the mycelium was absent or dead. Numerous inoculation
experiments with pure cultures of the fungus on healthy trees
under various conditions resulted in the reproduction of the typical
symptoms of the disease. P. citrophthora was re-isolated from
many bark lesions in which it had been present from one to eleven
months. Lemon fruits affected by Pythzacystis brown rot were
shown to be capable of inducing the same type of gummosis as that
caused by the fungus from gummosis lesions. The inoculation of
branches and large roots produced less severe infection than that of
the trunk.

A species of Fusarium is commonly found to be associated with
Pythiacystis gummosis, and the results of a few tests indicated that
it aggravates the severity of the disease but is incapable of initiat-
ing it,

Observations and experiments both showed the following decreas-
ing order of resistance to P. citrophthora: sour orange (Poncirus
trifoliata), rough lemon (a resistant variety of C. limonia), pomelo
(C. grandis), sweet orange, and common lemon. The inoculation
of small roots of young trees indicated that common lemon roots
are somewhat susceptible and those of sour and sweet orange and
pomelo resistant.

‘Mal di gomma’, due to Phytophthora terrestris, was shown to be
similar to the damage caused by P. citrophthora at the junction of
the main roots and trunk of old orange trees in California. In-
oculations with both these fungi, under identical conditions, produced
similar lesions.

Experiments showed that the disease may be largely prevented
by the application of Bordeaux mixture or paste to the trunks and
arrested in its progress by the excision of the affected bark and
treatment with a suitable fungicide. The outer gummous zone
eventually recovers and need not be removed.

Botrytis gammosis causes a softening of the invaded bark in the
early stages and on this area are produced conidiophores and conidia
in damp, cool weather. In the later stages the outer layer of bark
is killed and hardens long before the inner layer. As in Pythia-
cystis gummosis, there is a non-infected, outer gummous zone.
There is a stronger tendency towards the removal of the bark
under the dead layer than in Pythiacystis gammosis, and the flow
of gum is less copious. In California the Botrytis gummosis is
almost exclusively confined to trees over ten years of age growing
in the coastal regions and it is much more dependent than P. citro-
phthora on wounds or other predisposing conditions. A strain of
B. cinerea has been isolated from numerous lesions on trees affected

541

by gummosis, and the inoculation of healthy lemon trees with
fragments of the diseased bark and pure cultures of the fungus
resulted in typical symptoms of the disease. Attempts made to
induce gum formation by various kinds of wounds on lemon tree
trunks gave negative results when the wounds were kept free from
contamination by injurious organisms or chemicals. The disease
may be effectively controlled by cutting or scraping away the dead
bark, leaving intact the live inner layer next to the cambium, and
painting the treated area with Bordeaux paste or one of the coal-
tar products containing only the heavier oils.

Sclerotinia libertiana is occasionally found associated with rapid
drying of the bark on the roots and trunks of citrus trees growing
in damp, cool situations, especially after severe frosts. At first
there is a plentiful flow of gum and the bark is soft, but sub-
sequently the latter dries into long shreds and usually contains
flat, black sclerotia. Though the fungus normally advances more
rapidly than Botrytis, it is soon arrested and callus begins to form
when the gum accumulates. The results of inoculation experiments
with pure cultures showed that the fungus is able to produce the
typical symptoms of the disease on healthy lemon tree trunks.

A number of other organisms, besides the Fusariwm referred to
above, commonly found on the dead or decaying bark of citrus
trees were used in inoculation experiments on lemon and orange
trees to ascertain their relation, if any, to gummosis. A slight
amount of gum exudation from cuts was produced by Penicillium
rosewm, Diplodia sp., Corynewm beijerinckii, Coprinus atramenta-
rius, Alternaria sp., and Hypholoma sp. No definite pathological
symptoms, however, were produced. . Negative results followed in-
oculation with Cladosporiwim sp., Rhizopus sp., Spegazzinia ornata,
Penicillium digitatum, and Pseudomonas cerasi.

Gum in citrus is similar to cherry gum and gum arabic, and appears
to originate mainly in the xylem tissues by hydrolysis of the
cellulose walls. Mechanical injuries, continuous pressure on the
bark, and obstructions in the sap current by the insertion of glass
or wooden plugs and the like are incapable of causing gum forma-
tion in citrus trees when the tissues are healthy and not irritated
by such chemical stimuli as hydrocyanic acid, spray mixtures con-
taining copper sulphate not properly neutralized with lime, or ant
poison containing arsenic. Injuries by certain insects, e.g. Tortriz
citrana and grasshoppers, sometimes cause slight gum formation,
probably due to secretions by the insects or to contamination.

Observations. and experiments indicate that burning, freezing,
and partial desiccation are not in themselves important factors in
gum formation in citrus but merely aid the wood-rotting organisms
which later induce gummosis.

Certain chemical substances, chiefly acids, alkalis, and salts of
heavy metals (especially the last-named), can induce gum formation
when injected into citrus bark. In no case was it possible, how-
ever, to reproduce all the symptoms of any of the gum diseases by
such injections.

The results of comparative experiments with filtrates from
diseased and healthy tissue show that the former contain a sub-
stance capable of passing through a fine clay filter and inducing

542

gum formation. This was destroyed by boiling, indicating the
presence of a heat-sensitive enzyme in the filtrate from diseased
tissue.

A bibliography of 65 titles is appended.

Fawcett (H.S.). Gum diseases of Citrus trees in California.—
California Agric. Exper, Stat. Bull. 360, pp. 370-423, 15 figs.,
1928.

In this paper the available data on various types of citrus gum-
mosis are presented, with special reference to the incidence of the
diseases under California conditions. A full scientific description
of the Pythiacystis, Botrytis, mal di gomma, Sclerotinia, and other
milder forms of gummosis has been published elsewhere [see pre-
ceding abstract].

In California the type of gummosis induced by Pythiacystis
citrophthora is most prevalent on damp, heavy soils in the coastal
districts and occurs chiefly on lemon trees budded low on sweet
orange stocks. Temperature also plays an important part in the
development of the disease, which would explain the slow progress
of the disease during dry, hot periods and in the valleys of the
interior. Deep planting or the accumulation of soil next to the
stems also assists in the development of the disease. Full direc-
tions are given for the control of Pythiacystis gammosis by various
methods, according to the age and condition of the trees and other
factors. Among other forms of treatment may be mentioned spray-
ing with Bordeaux mixture; cutting out infected tissues and paint-
ing the wound with Bordeaux paste, benzine-asphalt, or other
suitable mixture; cutting back the tops of severely affected trees ;
and bridge grafting or inarching in certain cases.

Phytophthora terrestris, the causal organism of mal di gomma, has
only once been isolated from an orange tree in California, viz. in
1912, though the same or a closely allied species appears to be very
prevalent in Florida, Cuba, the Argentine, Jamaica, and India. In
Florida it causes a severe type of gummosis known as foot rot.
A certain form of this disease so closely resembles the Pythiacystis
gummosis as to be distinguishable only by careful laboratory
examination, and the control methods in both cases are practically
identical. The temperature relations of the two fungi are somewhat
different [see this Review, i, p. 312], the optimum for Phytophthora
terrestris being about 30° C.

Botrytis cinerea and Sclerotinia libertiana each causes a form of
gummosis {the symptoms of which are described in the preceding
abstract]. The control methods are essentially the same as those
recommended in the case of Pythiacystis and mal di gomma.

Psorosis or scaly bark, the most conspicuous feature of which is
the occurrence on the trunk and large branches of irregular scales
of bark, 4 to 1 inch in diameter, develops extremely slowly and it
has not yet been possible to ascertain the cause of the disease. It
is believed, however, that a parasitic organism is involved. The
disease is usually most active in the summer and early autumn
when it is accompanied by gum formation and exudation, the
gum appearing to arrest rather than promote the advance of the
disease.

|

543

Control measures for psorosis vary with the different stages of
the disease. At the beginning only an outer layer of bark appears
to be injured and the atfected bark may be scraped rather deeply
and the surrounding bark very lightly for four to six inches in all
directions beyond the margin of the diseased areas. When, how-
ever, the latter have extended so as to cover about one-third of the
circumference of the trunk, they should be scraped and disinfected
and the process repeated again six months or a year later. When
the disease has been present five, ten, or more years, there is little
hope of a permanent recovery, but such trees frequently remain
productive for a considerable time, and in cases of only moderate
severity the progress of the disease may be checked by drastic
pruning and the application of benzine-asphalt or some other cover-
ing to the bark after excising the decayed areas. The results of
experiments indicate that the best time for treatment is during
the late spring and summer months. Mercuric cyanide (1 part
in 500 of water) and alcohol (500 parts) is an excellent dis-
infectant.

Diplodia gamming occurs frequently in California, especially
San Diego, in connexion with the ‘heart rot ’ following severe frosts.
It may be prevented to some extent by treatment with a suitable
non-air-tight disinfectant, and by whitewashing all the pruned
parts of the tree to avoid sunburning.

Twig gumming, due to an unknown cause, occurs in California
and Arizona. It is characterized by the sudden wilting of leaves
and dying back of twigs to a distance of one to two feet from their
tips. At the base of the dead portion the bark splits and gum is
plentifully exuded. The disease often occurs after periods of
drought, and treatment on the lines described under Diplodia
gumming is recommended.

Exanthema or die-back, of only secondary importance in Cali-
fornia, is believed to be due to nutritional disturbances and is
characterized by dark excrescences and multiple buds on the branches,
the dying back of terminal branches, compact, shortened growth,
and dark irregular reddish-brown patches on the surface of the
fruit. Clear gum exudes from the pockets on the twigs or is found
internally near the centre of the fruit at the angles of the segments.
The use of nitrogenous fertilizers, which are considered to aggra-
vate the disease in Florida, has not proved injurious under California
conditions.

Minor forms of gumming associated with Penicilliwm rosewm,
a species of Fusariwm [see preceding abstract], Alternaria citri,
Bacteriwm citriputeale, and various fungi, as well as with insect
injuries and chemical stimuli, may generally be controlled by the
methods outlined above.

Gapp (C. H.), A possible physiological cause of ‘nut-fall’ of
Coco-nuts.—/rop. Agric., |x, 2, pp. 112-114, 1923.

The fall of immature coco-nuts in Ceylon cannot always be
attributed to the attacks of Phytophthora since it frequently occurs
in the absence of any pathogenic organism. Comparison with the
fall of young fruits after a period of drought in the case of citrus
and other plants suggests that a similar cause may be responsible

544

for the nut fall of the coco-nuts. The latter, however, takes place
in Ceylon principally on the heavy loam of the Kurunegala district
during the rains of the north-east monsoon, which tend to produce
a water-logging of the soil and thus interfere with the absorption
of water and the aeration of the root system. The author suggests
that these adverse conditions may result in premature dropping of
the fruits.

ARMSTEAD (Dorotuy) & Harianp (S. C.). The destructive
effect of micro-organisms on raw Cotton and Cotton fabrics:
a summary of the literature—Journ. Textile Inst., xiv, 6, pp.
T 157-T 160, 1923.

Cotton, both in the raw and when manufactured, is subject to
fungous attack, which results in ‘tendering’, due chiefly to
bacterial action, or in discolorations with or without pronounced
‘tendering’. The various fungi are known collectively to the
industry as ‘mildew’. The size employed in yarns and fabrics
provides an excellent medium for the growth of many fungi, and
generally an antiseptic is added in order to prevent such growth.

The authors divide the literature on the subject under the heads:
bacteria and fungi. Amongst papers dealing with the former,
brief extracts are given of four, which particularly interest the
cotton industry, and of those relating to fungi ten are shortly
summarized. A list of references terminates the paper.

RitzeMA Bos (J.). Eene nieuwe ziekte van de Zonnebloem. [A
new disease of the Sunflower. |—T%jdschr. over Plantenziekten,
Xx1x, 7, p. 128, 1923.

Referring to a disease of sunflower plants in Montana believed to
be caused by Sclerotinia libertiana (Phytopath., xi, 1, p. 59, 1921),
the writer states that the stalks of sunflowers in his garden at
Amsterdam were also attacked by the same fungus. The roots,
however, were not affected, as in the Montana specimens. Large
sclerotia were formed in the interior of the stalks and the whole
plant withered above the point of attack. The flowers were
growing in a very shady position.

KILLIAN (C.). Le Polythrincium trifolii Kunze parasite du
Trefle. [Polythrinciwm trifolic Kunze parasite on Clover.]—
Rev. Path. Veg. et Ent. Agric., x,3, pp. 202-219, 14 figs., 1923.

Trifolium repens is frequently attacked by the fungus Poly-
thrincium trifolit Kunze [in France]. The symptoms appear
at the end of June as granular black spots on the under side
of the leaves and limited by the veins. Their number and
diameter vary considerably. When large (at most 1 mm.) the
spots are at first few in number, though eventually the whole
under surface will be covered. Sometimes they are localized either
at the base or on the margins of the leaflets, and this may be
explained by the fact that the rain drops carrying the spores tend
to accumulate in the lower part of the leaflets, when these take on
an erect position at night. Infection in the spring can take place
from May onwards. Its initial localization makes it not easy of
diseovery, but later the disease progresses more rapidly, reaching

545

a climax at the beginning of autumn. Frosts completely arrest
further growth, and from January onwards the disease seems to
disappear altogether, though plants kept under glass during that
period will continue to show the spots.

On Trifolium repens the disease is usually benign, and in one
case only has 7. pratense been found attacked. T. incarnatum,
however, is very susceptible and whole fields of it may be entirely
destroyed ; conditions which make for vigorous growth in this host
also apparently produce increased virulence in the fungus.

The experiments made with 7. repens have demonstrated that
infection by P. trifolii is dependent on various circumstances which
are difficult to distinguish. Speaking generally, natural conditions
favour the success of the inoculations. Under moist conditions in
the greenhouse the period of incubation appears to be from four to
six weeks, while it may be even longer if the plants are kept in
a dry atmosphere. In the field, however, the state of the atmosphere
appears to have no influence on the incubation period, which under
these conditions only lasts six to nine days, although it greatly
affects subsequent growth. In dry weather the spots increase
little, or not at all, but growth is normal in damp conditions.
Infected leaves disintegrate much more rapidly than healthy ones,
and this process is the more intense the more virulent the attack.
After some weeks not a trace remains of the fallen and dried leaves,
the very minute débris being washed into the soil, and the
perithecia are thus enabled to survive for comparatively long periods
and re-infect the new crop; a case is cited where the fungus
persisted in the soil for five years. Control is very difficult if
not impossible, and the only means of checking the inordinate
spread of the disease would appear to be to delay the date of
sowing.

Pure cultures of the fungus could not be obtained, as although
the conidia germinated, the mycelium soon died since P. trifolii is
an obligate parasite. On the living leaves of clover the relatively
short germ-tubes penetrate the epidermis at the radial walls and
the mycelium then invades the underlying cells, progressing rapidly
in the intercellular spaces rather than in the palisade tissue. In
young leaves the mycelium penetrates later on into the cells them-
selves, but this is not usually the case in older leaves. When inside
the cells, the elements of the host and those of the parasite are
scarcely distinguishable, recalling an advanced parasitism such as
occurs in the rusts, and also, according to the author, in the
Ascomycete, Cryptomyces pteridis.

After being established in the leaf, P. trifolii begins rapidly to
form its reproductive organs. The hyphae, isolated at first, become
massed together near the epidermis, forming a plectenchymatous
cushion which increases in size and finally breaks through the
epidermis. The peripheral cells of the plectenchyma then grow out
into irregular lobes, in which all the protoplasm and the nuclei
from the old cells concentrate. On these lobes arise the conidio-
phores, which are of a peculiar structure, from which the fungus
derives its name. Instead of growing straight they develop spirally,
in the form of a screw. The conidia borne on their free ends are
two-celled, the larger cell containing a denser protoplasm and

M 3

546

a greater number of nuclei than the other, which is attached to the
conidiophore by a thick papilla, where at the least contact the
conidium becomes detached. Conidia are formed abundantly until
December, when their production gradually stops and is replaced
by the pyenospores which develop in pyenidia. The latter have
their beginning in the interior of the green leaf near the stomata,
through which the pyenospores are evacuated as fast as they are
formed. Towards the middle of December the pycnospores become
less abundant and their production ceases in January. Their place
is taken by the perithecia which carry the fungus over the winter.
These bodies are formed inside the green leaf simultaneously with
the pycnidia. Washed into the soil with the débris of fallen
leaves, they mature with the approach of spring. The apical
portion of the body then lengthens into a beak, perforated by
a narrow channel provided with periphyses. The 2 to 4 large,
fusiform asci contain 8 hyaline, two-celled, elongated and slightly
curved spores, measuring 26 by 6y. These asci are accompanied
by some proasci, which will take their place in due course. The
covering of the beak becomes much distended and ruptured in
places, and its disintegration eventually renders the ejection of the
ascospores possible. The latter start the infection in the spring, as
the author was able to demonstrate by actual inoculations.

The ascigerous stage of P. trifolii was named by Saccardo
Phyllachora trifolii, but the author, who examined ample living
material, states that the ascospores are always bi-cellular and that
this forbids the classification of the fungus under the genus
Phyllachora. He thinks that the choice can only lie amongst the
Hyalodidymae in the third section of the Dothideales, Plowrightia
being the genus selected, and that Phyllachora trifolii must there-
fore be replaced by Plowrightia trifolii.

Stewart (F.C.). Fruit disease problems of to-day.— Proc. New
York State Hort. Soc. 1922, pp. 61-69, 1923.

The following diseases are briefly discussed with special reference
to the present position of research on each. Raspberry mosaic;
fireblight [Bacillus amylovorus]; bitter rot or anthracnose of
apples | Glomerella cingulata], destructive attacks of which occurred
during 1922 in Ulster and Orange Counties (New York) and on
Long Island ; crown gall | Bacterium tumefaciens]; and cedar rust
of apples [Gymnosporungium juniperi-virginianae], which is
extremely prevalent in the Hudson Valley.

The problems of peach leaf curl [Zzoascus deformans] and cherry
leaf spot [Coccomyces hiemalis| may be regarded as solved by the
timely application of appropriate sprays.

Day (L. H.). Control of Pear blight in California. Amer. Fruit
Grower, xlili, 6, pp. 3 & 12, 3 figs., 1923.

In 1921 and 1922 the writer carried out experiments on Bartlett
pears to test the scarification method for the control of pear blight
| Bacillus amylovorus].

It was found that the scarifying operation had to be continued
for some distance beyond the confines of the visible signs of the

ae

547

disease and not the minutest particle of outer bark left on the
shaved area. The addition of glycerine [amount not stated] to
Reimer’s combination of cyanide of mercury and bichloride of
mercury (1 part of each to 500 parts of water) [see this Review, ii,
p- 274] greatly reduced the incidence of infection. Full directions
are given for the scarification treatment.

Experiments were also carried out with numerous disinfectants to
ascertain whether the disease could be controlled without resorting
to surgical measures. Some success was obtained by painting with
cresylic acid, silver nitrate in nitric acid, nitric acid, zine chloride,
zinc nitrate, iodine, and iodine salts. Zinc chloride was the most
promising of these substances, 98 per cent. of the treated cankers
on trees under eight years old being arrested by its action.

WoRMALD (H.). Blossom wilt of Plum trees.— Journ. Min. Agric.,
xxx, 4, pp. 360-363, 3 figs., 1928.

Blossom wilt of plum trees, caused by Sclerotinia (Monilia)
cinerea forma pruniis responsible for considerable damage in Eng-
land in certain seasons, the branches as well as the flowering spurs
being killed back. Serious outbreaks of this disease have been traced
not only to mummified fruits remaining on the trees during the
winter, but also to cankers, dead twigs, and spurs, as is also the
case in the corresponding blossom wilt of apple trees [S. cinerea
forma mali] (Journ. Min. Agric., xxiv, 5, p. 504, 1917).

In May 1923 the writer examined some Giant Prune plum trees,
many young branches of which were killed back from the tip for
a distance of six inches to over a foot. At the lower end of every
dead portion there was a flowering spur with brown, withered
flowers which usually bore green tufts consisting of the spore
chains of the fungus. Further examination revealed the presence
of a few dead twigs killed by the fungus in the previous year.
These had produced spore pustules during the winter and the
resulting spores served to infect the opening flowers. The wilt
was most severe in the vicinity of such twigs. No mummified
fruits had been left on the trees. The Czar and Purple Egg
varieties growing in the same plantation were scarcely affected.

The blossom wilt also infects the leaves and shoots, giving rise
to the ‘wither tip’ condition (Ann. Appl. Bot., v, 1, p. 28, 1918)
and to ‘shoot wilt’ (Ann. Bot., xxxvi, 143, p. 305, 1922). Subse-
quently the fruit may also become infected.

All dead wood should therefore be removed as early as possible
and the trees sprayed in the late winter with a solution containing
1 per cent. soft soap and 1 per cent. caustic soda. The disease is
liable to spread from plums to sweet cherries where the above pre-
cautions are neglected.

Dickson (B. T.). Raspberry mosaic and curl. Scient. Agric., iii,
9, pp. 308-310, 1923.

After briefly summarizing the literature on virus diseases of
raspberry, the author describes the symptoms, varietal susceptibility,
and spread of mosaic and leaf curl of this host [see this Review, i,
p. 218, and ii, p. 17].

The symptoms of mosaic vary with the time of infection and the

548

weather. Canes newly infected in spring and early summer
develop new leaves which usually show many dark green blisters
in marked contrast to the pale yellow remainder. The petioles are
slender, the leaflets rather spindly, and if the dark green areas are
near the midribs the margins are rolled down and in. Under dry
weather conditions the later leaves are speckled and have somewhat
shorter petioles and broader leaflets. Late infections also usually
produce the speckled condition, although in the following spring
the blistering and distortion of the leaflets occur. As a rule the
cane is somewhat dwarfed and spindly. In fruiting canes diseased
laterals are liable to be spindly and weak. There is a distinct
tendency for infected plants to flower earlier than normal, and the
fruit becomes more and more tasteless, with also a reduction in

ulp. Once a plant is infected it never recovers, and diseased plants
should therefore be removed. Of the varieties commonly grown
none is resistant, but St. Regis and Sunbeam seem least susceptible.
The agent in the spread of the disease is probably Aphis rubiphila ;
pruning does not appear itself to be an important factor.

Leaf curl is also a systemic disease from which the plants never
recover. The leaf symptoms are the dwarfing of the petioles, the
arching and ruckling of intervenal areas, and the dark green or
quite yellow colour of the leaves. Severely infected leaves are
reduced in size, the leaflets sometimes measuring only half an inch.
The canes are dwarfed but are thick and stocky. The fruiting
laterals are short, have an upright tendency, and bear curled,
compact, dark green, small leaves. They flower late and the fruit
is small, bitter, and often with no pulp. Columbia and Newman 1,
23, and 24 varieties are resistant. Aphis rubiphilu, as shown by
Rankin, is undoubtedly the infecting agent in leaf curl.

Control measures for both diseases consist in thorough roguing
and burning the diseased plants. Early eradication appears to be
commercially successful, and when plantations are badly infected
they should be scrapped and new ground planted with disease-free
stock. Tests regarding insect control are necessary before recom-
mendations on this point can be made.

Hvorledes skal man bekjaempe stikkelsbaerdraeperen ? [ How is
the control of Gooseberry mildew to be accomplished ?|—Norsk
Havetid., xxxix, 7, pp. 114-115, 1923.

The following results were obtained in a series of spraying
experiments against gooseberry mildew [Sphaerotheca mors-uvae],
carried out in two different districts of Norway on over 250 goose-
berry bushes with (1) coarse Spanish common salt; (2) formalin ;
(3) lime-sulphur 20° Baumé; and (4) solbar. The disinfectants
were applied on 8th May (winter spray), and twice in the latter
half of June (summer spray) in the following strengths: salt 4 kg. per
100 1. (winter) and 2 kg. per 100 1. (summer); formalin 1 in 40
(winter) and 1 in 100 (summer) ; lime-sulphur 1 in 4-75 1. (winter)
and 1 in 18-25 1. (summer); solbar 4 kg. per 20 1. (winter) and
1 kg. per 100 1. (summer). In all cases the incidence of disease
was reduced considerably when both winter and summer applica-
tions were given, salt and lime-sulphur giving the best results. The
winter spray alone was ineffectual.

549

KELSALL (A.). Experiments on the dust method of smut control.
—Scient. Agric., iii, 9, pp. 303-307, 1923.

These experiments, conducted by members of the Annapolis
Entomological Laboratory with Professor W. S. Blair, had for their
primary object the testing of the fungicidal properties of various
insectide-fungicide dusts. The experiments, however, also yielded
results of practical value regarding the most efficient and cheapest
method of controlling smut by seed dust treatment.

In the experiments carried out in 1921, Liberty oats were treated
by sifting the dust over the seed, which was then turned over
several times and bagged. Five oz. of dust were used to 20 lb. of
grain. The following materials were used on the various plots.
Plot 1: grain soaked in water 10 minutes, partly dried and then
soaked in formalin, 1 pt. to 40 galls. [American] for 3 minutes,
partly dried and sown immediately. Plot 2: control. Plot 3:
dusted with 28-5 per cent. dehydrated copper sulphate mixed with
71-5 per cent. infusorial earth (which acted as an inert filler).
Plot 4: dusted with 28-5 per cent. dehydrated copper sulphate and
71-5 per cent. hydrated lime. Plot 5: the dust used was made as
follows: 53 parts of stone lime were slaked with a little water,
40 parts of crystal copper sulphate being added meanwhile, and the
whole thoroughly mixed. The copper in this dust was in the form
of an oxide or hydrated oxide. Plot 6: dust contained 10 per cent.
dehydrated copper sulphate, 5 per cent. calcium arsenate, and
85 per cent. hydrated lime—a general dust then in use. Plot 7:
similar to plot 4 but the grain was moistened with water before
applying the dust. The germination of the seed did not appear to
be injured in any plot, and the percentages of smut present in the
plots were (1) 52-1, (2) 61-3, (3) 2-5, (4) 16-2, (5) 45-8, (6) 72-9,
(7) 9-5, from which it is evident that plot 3 gave the only results
for practical purposes, and that wetting the grains before dusting
with copper sulphate and lime increased the efficiency of this
treatment.

In 1922 Liberty oats were again used, but the dusting was carried
out ina small churn. In each case 4 oz. of dust per bushel of seed
were used. Thirty plots were sown, each one-thirtieth of an acre
in extent. The trials were divided into three series. Series A,
with dehydrated copper sulphate (10 per cent. Cu) mixed respectively
with the following fillers, infusorial earth, calcium carbonate, gyp-
sum, talc, hydrated lime, gave 4-8, 5-4, 7-6, 2-0, and 7-0 per cent.
smut respectively; the first mixture, with the proportions altered
so as to contain 5, 10, 20, 30 per cent. of Cu gave 18-3, 7-1, 3-4,
and 3-3 per cent. smut respectively ; the control gave 46-4. Series
B, with the following pure chemicals, gave the percentages of smut
indicated: dehydrated copper sulphate (3-9), copper carbonate (1-5),
copper oxide (24-1), copper sulphide (1-9), copper arsenate (3-4),
copper arsenite (1-0), dehydrated aluminium sulphate (17-7),
dehydrated nickel sulphate (3-6), dehydrated cobalt sulphate (4-9),
and the control 33-6. Series C, with certain miscellaneous dusts,
yielded the following percentages of smut ; 50 per cent. dehydrated
copper carbonate and 50 per cent. tobacco dust (6-8), copper carbon-
ate (25 per cent. Cu) (1-1), prepared Bordeaux (12 per cent. Cu)
(8-5), sulphur dust (3-5), inoculated sulphur dust (2-8), whilst the
control gave 46-4.

550

From the above results it is seen that control was in no case
perfect but approached perfection in certain cases. Copper arsenite
was the most effective substance used, but has the disadvantage of
being highly poisonous. From series A,it would appear inadvisable
to attempt diluting dehydrated copper carbonate with inert materials,
although tale gave good results in this connexion. The fairly effec-
tive control with sulphur dusts is important in view of the cheap-
ness of the material, and the results may be improved by using the
substance in greater proportions.

When absolute control of smut is not required, the author tenta-
tively recommends the use of copper carbonate dust, or sulphur
dust (about one-sixth of the cost of the former) in somewhat larger
quantities.

AUSBORN. Ein Heisswasserbeizversuch gegen den Flugbrand. | A
hot water steeping experiment against loose smut. |—Deutsche
landw. Presse, |, 14, pp. 125-126, 1923.

In the spring of 1922 the writer immersed some Bordeaux wheat
seed, heavily infected with loose smut [Ustilago tritzci], in water
heated to a temperature of 50° to 52°C. for ten minutes, after
a preliminary soaking in cold water. After rinsing in cold water
the treated grain was spread out to dry. A very good yield was
obtained and there was a reduction in the number of smutted ears
of one-half to one-third compared with the untreated controls.
Complete prevention of the disease, however, appears to be
impossible by this means even when the directions of the Biological
Institute [Dahlem] are exactly followed, as in the present instance.

MAHNER (A.). Feldversuch mit Beizmitteln zur Bek’ampfung des
Haferbrandes. [Field experiments with disinfectants for the
control of Oat smut.|—Wiener landw. Zert., \xxiii, 13-14, pp.
50-51, 1923.

In the spring of 1922 a series of experiments in the control of
oat smut [ Ustilago avenae| was carried out at Hartmanitz, Czecho-
Slovakia. The soil consisted of gneiss decomposed sand, and the
slightly sloping field was situated 640 metres above sea-level. The
following fungicides were tested; copper sulphate, germisan,
formalin, segetan, uspulun, and the Dupuy and Aussig seed steeps.
The seed was procured from heavily infected 1921 crops.

The best results were obtained by steeping the seed for four
minutes in a 1 per cent. copper sulphate solution after washing it
in clean water (Linhart’s method), or for half an hour in 0-5 per
cent. germisan. The latter method is preferable in practice, as the
slightest neglect with copper sulphate leads to a serious reduction or
even complete failure of germination.

Muuuer (H.C.). Die Bedeutung der ertragsteigernden Wirkung
einiger Beizstoffe fiir die Volksernahrung. [The significance
for the national food supply of the increased productivity
ensured by certain disinfectants.]— Vachrichtenbl. deutsch.
Pflanzenschutzdienst, iii, 8, pp. 57-58, 1923.

The results of experiments conducted at the Halle Phytopatho-
logical Experiment Station have shown that the use of stimulating

d51

seed disinfectants (i.e. those containing arsenic, phenol, mercury,
and the like) increases the yield of the resulting crops in a very
high degree. Thus in one instance the yield per acre of wheat
treated with a stimulating disinfectant was increased by about 5
dz. per hect. [4 ewt. per acre], and in another oat crop was
augmented by about 2-5 dz. per hect. [2 cwt. per acre]. As the
wheat had only absorbed about 51 gm. and the oats approximately
153 gm. of the fungicide, the increase in the yield was out of all
proportion to the expenditure on material. This result is approxi-
mately equal to that obtained by the application to the soil of 15 kg.
nitrate nitrogen.

It is pointed out that, by the judicious use of fertilizers and
stimulating seed disinfectants, an average increase in the cereal
yield of 4 dz. per hect. [3-2 cwt. per acre] could be obtained, and the
necessity of importing large quantities of foreign grain thereby
obviated.

Binz (A.) & Bauscu (H.). Versuch einer Chemotherapie des
Gerstenbrandes. [An experiment in the chemotherapeutical
treatment of Barley smut. ]—Zeitschr. angew. Chemie, xxxv, 41,
pp. 241-243, 1922.

The successful results of empirical chemotherapy in human
infectious disease suggested to the authors that similar treatments
inay be applied to diseases of plants. Ehrlich’s plan was to
determine the chemotheropeutical index [the ratio of the minimum
healing concentration of the medicine, (c) or dosis cwrativa, to the
maximum dose the patient will stand, (t) dosis tolerata or toxica|
for a number of chemicals, and choose the ones for experiment
in hospitals in which the index [quotient c/t] was very small;
the smaller the index the more certain and less risky being the cure.

The difficulty of applying these methods to plants les in the
absence of a blood stream in the latter. The authors were
encouraged by Riehm’s work, however (Mitt. Biol. Reichsanst. Land-
u. Forstwirtsch., xxi, p. 136, 1921), and attempted the problem.
The method they adopted was as follows: spores of the covered
smut of barley were introduced with the point of a flamed needle
into a tube of the disinfectant to be tested. The tube was shaken
and then allowed to stand 30 minutes, after which the liquid was
filtered off and the filter paper left overnight exposed to the air to
dry [no mention is made of washing]. They then spread out the
filter paper, to which a number of spores were attached, on a Petri
dish and added a nutrient solution of 0-5 per cent. calcium nitrate as
recommended by Riehm, who found that this medium discouraged
the development of moulds. The liquid formed a layer 2 to 3 mm.
deep in the dishes. The latter were exposed to diffused light at
room temperature and spores were taken every day and examined
under the microscope to see how the germination had progressed.
Using this method [with various concentrations of the disinfectant]
they determined the minimum concentration necessary to inhibit
germination (the dosis cwrativa of Ehrlich). Spores which were
not disinfected but otherwise treated similarly germinated in 2 to
3 days.

For the determination of the maximum concentration the barley

552

seed would stand, healthy seed was placed in the disinfectant to be
tested and treated in a similar way except that after drying [on
the filter paper] the seed was placed on damp filter paper to
germinate, and by determining the concentration which impaired
germination the dosis toxica of Ehrlich was ascertained.

The authors tested the following substances at the concentrations
given: formalin 0 to 1 per cent.; uspulun 0 to 2 per cent.;
salvarsan and neosalvarsan 0 to 1-5 per cent.; atoxyl 0 to 1 per
cent.; 4-aminophenyl-l-arsenoxide 0 to 1-5 per cent.; 3-amino-4-
oxyphenyl-arsenoxide 0 to 1 per cent.; arsenic acid 0 to 1-57 per
cent. ; and three substances named A, B, and C, the composition of
which is not disclosed, at 0 to 1-5, 0 to 2, and O to 3 per cent.
respectively. None of these substances was any good except
formalin, uspulun, and A, B, and C. The substance B was very
good and C was excellent, the germination of the seed in the latter
case not being impaired until 40 times the doszs cwrativa (0-05 per
cent.) was used.

A principal result of these investigations is the knowledge of the
fact that Ehrlich’s conception of the chemotherapeutical index is
applicable to vegetable as well as to human pathology.

RIEHM (E.). Zur Chemotherapie der Pflanzenkrankheiten. [Con-
tribution to the chemotherapy of plant diseases. ]—Zeztschr.
angew. Chemie, xxxvi, 1, pp. 3-4, 1923.

Referring to the work of Binz and Bausch on the chemothera-
peutical index [see last abstract], the author points out that the
term ‘chemotherapeutics’ is strictly applicable only to the
destruction by chemical substances of pathogenic organisms in
the interior of cereal or other seeds. The steeping of cereal seed to
protect it against smut spores adhering to the exterior, the spraying
of vines against downy mildew [Plasmopara viticola], and other
preventive measures are purely prophylactic. The only genuine
chemotherapeutical remedies so far discovered are the cure of
chlorosis of vines and fruit trees by spraying with, or injection of,
iron sulphate, and the destruction of the Fusariwm and stripe
disease | Helminthosporium graminewm| organisms in the interior
of seed grain by immersion in mercury salts.

The author’s method of determining the [minimum] spore des-
troying concentration [dosis curativa] of a chemical substance (see
Mitt. Biol. Reichsanst., xviii, p. 19, 1920), has been modified some-
what as follows: a given quantity (0-3 gm.) of smut spores is
placed in a test tube and shaken up with a small quantity of the
fungicide, with which the tube is then filled to the brim. One
prevents by this means any spores remaining attached to the glass
and not being wetted. After half an hour most of the liquid is
poured off and thrown away, together with any spores floating on
the surface. The remaining spores are then thoroughly shaken and
filtered through two separate filters, one of which is left to itself
while the spores in the other are immediately washed with water
several times. This washing at once prevents further action by the
fungicide, which continues to act, however, on the spores in the
other filter until they are dry, thus corresponding to normal field

553

conditions. Next day after the spores have dried, a small quantity
of the spore mass is removed with a platinum needle and placed in
a Petri dish in a solution of 25 per cent. calcium nitrate. The
method of Binz and Bausch, whereby the entire filters are placed
in the solution, is suitable for covered smut of barley [Ustilago
hordez| but not for bunt of wheat [Tilletia tritici]. The spores of
the latter do not germinate when sown in high spore concentrations
and should not be used in quantities exceeding 5 mg. per 15 ec. of
calcium nitrate. The spores of U. horde germinate in two days
and those of 7. trztici in three to four days in diffused light at
a temperature of 20°C. Direct sunlight or total darkness delays
germination, as also do temperatures below 20°C. Spores treated
only in water should be cultivated for purposes of comparison.
There is little danger of the development of moulds in the solution;
Acrostalagmus sp., however, has been known to occur occasionally.

The dosis toxica or dosis toleruta was ascertained by Binz and
Bausch by exposing barley seeds to the fungicide, drying them, and
spreading them out on damp filter paper for germination.

All the authorities are agreed that an accurate and reliable
estimate of the germinating power of seed which has been immersed
can only be obtained by testing at least 200 seeds. Even when
a reliable estimate of germination has been obtained in these tests,
however, the effects of the fungicide on the plants in the field
cannot be exactly foretold. Numerous experiments have shown that
while | percentage] germination is not in the least impaired by many
solutions the seedlings do not thrive and are lacking in germination
energy [‘Triebkraft’] with the result that the stand is defective.
This shows that the fungicide has in some way weakened the
natural forces of the seed, which may retain sutlicient energy to
develop under optimum conditions in the laboratory but not when
exposed to the rigours of the field. Hiltner has therefore devised
the following system of ascertaining such effects on the constitution
of the seed: the seeds to be tested (at least 200) are laid on a layer
of damp brick dust in zine tins, covered with another layer of damp
brick dust 3 to 4.cm.in height and left for a fortnight. The energy
of the seed is judged by the number of plants which have come up
at the end of this time. In this connexion it must be remembered
that different varieties of wheat vary considerably in their suscepti-
bility to the same concentration of a chemical substance and a com-
parison between two fungicides should only be made when tests
have been carried out on the same variety of wheat.

The theoretical fungicidal value of a. chemical substance is
determined as follows: the concentration at which germination
energy or speed of germination is reduced by more than 10 per
cent. is first ascertained, using at least tive varieties of wheat. The
next step is to discover the [minimum] concentration at which the
spores of Ti/letiu tritici the most important fungus in agriculture—
are destroyed. The theoretical fungicidal value of the substance is
obtained by dividing the concentration at which germination
energy is reduced by more than 10 per cent. by the spore-
destroying concentration. The higher the quotient, the better the
results to be anticipated in field trials with the disinfectant in
question. [This is approximately the reverse of the chemothera-

M 4

3054

peutical index as calculated by Binz and Bausch and also by
Gassner : see last and following abstracts. |

Spores of 7’. tritici steeped for 30 minutes in a 0-1 per cent.
copper sulphate solution do not germinate in calcium nitrate and
few do so after 0-01 copper sulphate. It might be assumed from
these laboratory experiments that the spores were killed by 0-1 per
cent. copper sulphate but this is not the case. Hecke has shown
that normal germination is restored by rinsing them in diluted
hydrochloric acid (0-5 per cent.). Probably in the field the humic
acid in the soil is also capable, under certain conditions, of washing
the copper off the spores adhering to treated seed, which would
account for the appearance of smut on the plants from treated seed
when sowing has been immediately followed by heavy rains. It is
thus essential to confirm by field tests the results of laboratory
experiments.

GASSNER (G.). Biologische Grundlagen der Priifung von Beiz-
mitteln zur Steinbrandbekampfung. [Biological principles
underlying the testing of fungicides for seed treatment against
bunt.]—Arb. Biol. Reichsanst. fir Land -und Forstwirtsch.,
xi, 5, pp. 889-372, 1923.

While field trials remain the most reliable means of determining
the efficacy of the numerous new preparations released by chemical
works for the disinfection of seed grain, they are extremely lengthy
and costly, and too much dependent on uncontrollable factors such
as climate, weather conditions, and lack of scientific training in
farm staffs entrusted with the trials. These drawbacks call for
laboratory methods which can be conducted under strictly con-
trolled conditions within a short time. Some work has already
been done in this direction by Riehm (Mitt. Biol. Reichsanst., xviii,
p- 19, 1920), who investigated in spore germination tests the
fungicidal action of different chemical compounds on smut spores.
It is obvious also that chemical works must test their preparations
in the laboratory without, however, being quite clear as to how far
their results apply in practice. As a matter of fact, the results of
laboratory experiments, as hitherto conducted, seldom, if ever,
agree with those of field trials, thus justifying doubts as to the
value of such experiments. The present work is an attempt at
developing a laboratory technique in conjunction with field trials
so as to obtain numerical indices of the comparative value of the
different fungicides offered to the public.

The efficacy of a disinfectant depends on two main factors:
firstly, on its specific lethal action on the parasite, and, secondly, on
its harmlessness for the host. The notion that both factors must be
equally considered is old and was unconsciously applied even before
pathogenic organisms were known. The numerical computation of
the action of a therapeutical preparation on the host and on the
pathogen, however, was first applied by Ehrlich (Die experimentelle
Chemotherapie der Spirillosen, Berlin, 1910) to the testing and
discovery of new remedies in human and animal pathology.
According to this author the medicinal value of a chemical prepara-
tion is determined by its chemotherapeutical index, which is
represented by the symbol ¢ and is equal to eft, e¢ being the dosis

555

curativa and t the dosis toxica [see above, p. 551], both being
calculated in relation to unity of weight of the animal body.

In 1918 the author began a series of experiments in the control
of bunt of wheat [Tilletva tritici and T. levis] with the object of
applying the principles outlined above to the treatment of plant
diseases. The dosis cwrativa may be defined as the minimum con-
centration of a disinfectant which will destroy the spores of the
fungus. The spores must therefore be treated in a certain way and
the effect of the fungicide on their subsequent germination carefully
noted. The method adopted in the present series of investigations
was immersion of the bunt spores for one hour in the fungicide to
be tested, at a temperature of 18°C., with subsequent rinsing. The
germination medium used was a 0-1 per cent. solution of calcium
nitrate in distilled water, the dishes being maintained at a constant
temperature of 15°C. Under these conditions untreated spores
germinated in 3 to 5 days, whereas the previous immersion in
uspulun, formalin, or germisan delayed or prevented germination
according to the strength of the concentration. It was frequently
observed that spores treated with a solution which was sufiiciently
strong to control the diseases in the field completely, nevertheless
germinated after weeks or months in the laboratory. Therefore
the action of such solutions is not, strictly speaking, destructive but
merely in a very high degree repressive. The results of field
experiments with treated Schlanstedter summer wheat showed that
even a slight retardation in spore germination (five days) greatly
reduced the incidence of infection, while absolute control was
secured when germination was delayed for seven to eight days.
Hence the dosis curativa is represented by the minimum concentra-
tion of a solution which, under the conditions described above,
retards germination for ten days. In the present series of experi-
ments the dosis curativa was as follows: formalin 0-13 per cent. ;
germisan 0-12 per cent.; uspulun 0-08 per cent.; mercury cyanide
(with a 17-5 Hg-content) far above 10 per cent.

The dosis toxica (equivalent to Ehrlich’s dosis tolerata) is that
concentration of a disinfectant which, at the end of a given time,
shows the first indications of a deleterious effect on the grain.
In caleulating the dosis towica several factors arise in connexion
with the germination of the seeds which need consideration.

From experiments on the action of different formalin solutions on
wheat grain, it was found that an increase of the percentage of
germination was also accompanied by a corresponding improvement
in the speed of germination. Conversely a lowering of the
germination percentage gave also a retardation in germination.
The full germination percentage, however, was also reached in
certain cases of retarded germination. Thus immersion for one
hour in 0-2 per cent. formalin resulted in a delay of germination of
about eight hours, although practically all the seeds germinated.
The decline in the germination percentage on the one hand and the
retardation of germination on the other must therefore be con-
sidered in judging the effect of a fungicide on the treated seeds, and
it is advisable that the figures for the dosis toxica should take into
account both these effects.

When the injurious action on the seed increases there is a decline

556

in the germination percentage and, at the same time, an increase in
the time taken for germination. The figure expressing the real
effect on the grain is therefore found by the division of germina-
tion percentage by the speed of germination (expressed in
days). In order to obtain comparative values between experi-
ments not simultaneously undertaken, the quotient, germination
percentage/speed of germination, is compared with that quotient
obtained from seed treated only with water in place of the disin-
feetant. The quotient from the water treated seeds is taken to be
equal to 100, and from this is calculated the values for seeds treated
with the fungicides, which values are taken as the index figures of
the effect of the fungicide on the grain.

The author’s method of determining the dosis toxica was as
follows: the seed (20 gm.) was immersed in at least 60 cc. of the
fungicide for exactly one hour, rinsed, washed for 30 minutes in six
changes of water, and dried. Seeds were also treated in water in
the same way for control. At least 200 seeds were used in each
germination test in each experiment and for the control 400 were
used. The seeds were germinated on filter paper in Petri dishes in
the dark at a temperature of 15°C. Every day they were
examined, the standard for germination being a leaf and three
healthy roots. The tests lasted 6 days. From data obtained in
this way the percentage germination, the speed of germination, and
tinally the index figure (the control being 100) was calculated.

Tests have shown that the experimental error does not exceed 5
per cent. of the index figure as a rule, and all index figures under
95 per cent. indicate that there is a slight injury to the seed. The
dosis toxica therefore is that concentration at which the index
figure falls below 95 per cent. on the average in several parallel
series of experiments. It is necessary always to use the same
variety of cereal; the author used Strubes Schlanstedter summer
wheat.

After having determined the dosis curativa and the dosis toxia
by the methods described above, the calculation of the chemothera-
peutical index is made by dividing the dosis curativa by the dosis
toxzica. In the case of the fungicides used in the author's experi-
ments the dosis curativa was: formalin 0-18; germisan 0-12;
uspulun 0-08, and mercury cyanide over 10; the dosis toxica was:
formalin 0-1; germisan 0-35; uspulun 0-25; and mercury cyanide
0-9 (all in percentage strengths of the solution) and the index
worked out as follows: formalin 1-3; germisan 0.34: uspulun 0.32 ;
mercury cyanide (17-5 per cent. Hg) over 11. It will be seen that
the resulting quotient places germisan and uspulun in a much more
favourable light than formalin, while mercury cyanide occupies a
very inferior position.

‘The above calculations of the chemotherapeutical index are made
only in reference to the effect of the fungicide when used for
immersion, and the author in the latter part of his paper discusses
a modification of the method to express the efficiency of the ©
fungicide applied by sprinkling. He determined the dosis ewratiwa
for sprinkling experimentally, taking wheat strongly infected with
bunt, and using 25 gm. which was sprinkled with 5 ce. of disin-
fectant, the seed being then stirred for 2 minutes and immediately

357

after spread on a filter paper in a layer 1 cm. thick to dry. After
drying the spores were germinated at 15°C. in 0-1 per cent. calcium
nitrate solution. It was found that the dosis curativa from
sprinkling was as follows: formalin 0-05; germisan 0-14; uspulun
0-33; mercury cyanide 2 per cent.

In order to define these differences between immersion and
sprinkling the author introduces the sprinkling coefficient B (the
number by which the factor c¢ in immersion must be multiplied in
order to obtain the dosis curativa (cB) as determined for sprinkling).
Hence the factor B for formalin is 0-5 [the author taking ¢ = 0-1
in this calculation]; for germisan 1-2; for uspulun 4-1; and for
mercury cyanide less than 0-2.

The determination of the dosis toxica by sprinkling was made
and it was found that the alteration in the effect of the sprinkling
as compared with immersion moved in the same direction as in the
case of the dosis cwrativa. Hence by multiplying the factor for
immersion by B he obtained a figure approximately equal to that
of the doszs toxica for sprinkling, 1. e. the concentration in sprinkling
which produces the first signs of injury to the seed.

In conclusion the author discusses the chemotherapeutical index
of the four substances tested. He points out that formalin with
an index of 1-3 is unsatisfactory, as a certain amount of seed
injury must be expected at a concentration which will kill the
fungus spores. Germisan and uspulun with indices of 0.34 and 0-32
respectively are quite satisfactory, but mercury cyanide with an
index of more than 10 is extraordinarily unsatisfactory. Generally
speaking, the limits of the index of a satisfactory substance should
not be allowed to exceed 0-5.

GAssNER (G.) & Esporn (ILSE). Beitrage zur Frage der chemo-
therapeutischen Bewertung von Quecksilberverbindungen als
Beizmittel gegen Weizenstinkbrand. [Contributions to the
problem of the chemotherapeutical value of mercury compounds
as disinfectants against bunt of Wheat.|—Arb. Biol. Reichsanst.
fiir Lond- wnd Forstwirtsch., xi, 5, pp. 373-385, 1928.

A series of experiments, based on the principles outlined in the
preceding abstract, was conducted with a view to ascertaining the
fungicidal properties of a number of substances, the mercury
content of all of which was equalized at 17-5 per cent. by the addition
of the necessary quantity of sodium chloride and sodium sulphate.

The values for the inorganic mercury preparations tested were
as follows: (P 1= Preparation No. 1) Corrosive sublimate; ¢ (dosis
curativa) 0-025 ; t (dosis toxica) 0-1; ¢/t (chemotherapeutical index)
0-25; cB (dosis cwrativa by sprinkling) 0-08; B (sprinkling coefficient)
3-2. (P 6) Disodium mercurous thiosulphate; ¢ 3-0; t 5-5; e/t
0-55; cB 3-5; B 1-2, (P 4) Mercuric cyanide; c over 10; t 0-9; ef
over 11; cB 2-0; BO-2. (P3) Mercuric oxycyanide ; ¢ 0-1; t 0-28; ¢/t
0-36 cB 0-21; B 2-1. (P 5) Double salt of the cyanides of mercury
and potassium ; c over 10; t 0-9; c/ over 11; cB 3-0; B < 0:3.

The following list gives the corresponding values for the organic
preparations tested: (P 30) Mercury methyl] iodide; ¢ 0-001; t
0-015; ¢/t 0-07: cB 0.008; B 8-0. (P 21) Sodium hydroxynitro-
phenylmercury sulphate ; ¢ 0-07; t 0:3; ¢/t 0-23; cB 0-28; B 4-0.

558

(P 15) Sodium hydroxychlorphenylmercury sulphate; ¢ 0-08 ; t 0-25 ;
c/t 0-32; cB0-33; B4-1. (P8) Hydroxysulphophenylmercury hydro-
gen sulphate; ¢ 0-18; t 0-7 ; c/4 0-26; cB 0-4; B 2-2. (P 7) Sodium
salt of hydroxycarboxyphenylmercuric hydroxide; ¢ 2-0; t 2-5;
c/t 0-8; cB 1:0; B 0-5. (P 10) Sodium salt of methylhydroxy-
carboxyphenylmercuric hydroxide: ¢ 0-22; t 1-1; ¢/6 0-2; cB 0-4;
B 1-8. (P 19) Sodium hydroxychlorphenylmercury sulphate,
dissolved in sodium thiosulphate; ¢ 2-5; t 2-4; co 1-0; cB1-5;
B 0-6. (P 17) Sodium hydroxymethylphenylmercury sulphate, dis-
solved in sodium thiosulphate ; ¢ 3-2; t 2-5; ¢/f 1:3; cB 1-3; BO-4.
(P 25) Sodium salt of hydroxymethylphenylmercuric cyanide; c¢
0-12; t 0-35; cA 0-34; cB 0-14; B 1-2. (P 28) Sodium salt of
mercury carboxyphenyl cyanide; c 0-2; t 0-8; c/ 0-25; cB 0-6;
B 3-0. (P 29) Sodium salt of mercury hydroxycarboxypheny]
cyanide ; c far above 5 ; t 1-6; ¢/t farabove3; cB 2; Bmuch < 0-4.
(P 23) Sodium salt of symmetrical dihydroxy mercury dipheny] ;
e 0-05; t 0-17; ct 0-29; cB 0-18; B 3-6. (P 24) Sodium salt of
symmetrical dihydroxydicarboxy mercury diphenyl; ¢ 1-0; t 1-4;
c/t 0-7; cB 1-0; B 1-0. (P 27) Sodium salt of mereury phenol-
phthalein; c1-8; t 1-3; ¢/6 1-4; cB2-0; B1-l. (P 22) Sodium
salt of mercury fluorescein c 2-0; t 1-7; c/t 1-2; cB 3-0; B 1-5.
(The formula for most of these compounds is given. ]

Four decisive factors must be considered in determining the
utility of a mercury disinfectant. These are (1) a sufficiently low
chemotherapeutical index ; (2) a sprinkling factor approximating as
nearly as possible to the figure 1: this factor indicates the higher
or lower concentration to be employed in the sprinkling method in
order to obtain the same results as with immersion, and the more
closely the strengths for both methods coincide the more valuable
is the substance in question; (3) the preparation should combine
efficiency with as low a mercury content as possible in order to
promote its use on a commercial scale; (4) the degree of toxicity to
human and animal organisms should be as low as possible. As
regards the last-named point the majority of the organic mercury
compounds are less toxic than some of the inorganic, e. g. corrosive
sublimate. Other things being equal, these relatively innocuous
products should be preferred.

An analytical survey of the values given above shows that the
mercury compounds with the lowest dosis cwrativa have the most
favourable chemotherapeutical index and vice versa. Thus all the
preparations with effective action on the spores are at the same
time comparatively harmless to the seed; the dosis curativa in
such cases is 4 to + smaller than the dosis toxica. On the other
hand the higher the dosis cwrativa the less favourable is the
relation between spore destroying and seed impairing activity.

A comparison between the chemotherapeutical index and dosis
curativa on the one hand and the sprinkling coefficient B on the
other also reveals, with striking regularity, that the mercury com-
pounds with the most favourable chemotherapeutical index and the
lowest dosis curativa generally have the highest sprinkling co-
efficient and vice versa (cf. P 30, P 1, P 23 with P 4, P 5, P 29).

The chemotherapeutical index is the fundamental criterion for
the determination of a given substance. All the compounds in

599

which this index is higher than 0-5 must be rejected as disinfectants
since the necessary strong concentrations involve risk of injury to
the germinative capacity of the seed.

In addition to P 30, P1, P 23, P 21, and P 15, shown above to
combine low concentrations with high fungicidal efficiency, P 10,
P 28, P 8, P 25, and P 3 may also be recommended.

By far the most efficient of the products tested was P 30, mercury
methyl iodide, but on account of the extremely poisonous nature
of the compound it could not possibly be recommended for practical
purposes.

It was difficult to determine the respective merits of some of the
other compounds tested. Corrosive sublimate combines fungicidal
efficiency with a low spore destroying concentration, 0-05 per cent.
for immersion and 0-15 to 0-2 per cent. for sprinkling. On account
of its toxicity to animals, corrosive sublimate may well be replaced
by P 25, which also has a very favourable sprinkling coefficient.
P 3 is inferior to P 23, P 21, and P 15 in respect of the dosis cwrativa
and the chemotherapeutical index, but superior to these prepara-
tions in its very favourable sprinkling coefficient. Any of these
compounds may safely be recommended as disinfectants, adequate
quantities for practical purposes being approximately for immersion :
P 3 0-2 per cent.; P 23 0-1 to 0-15 per cent.; P 21 0-2 per cent. ;
P 15 0-2 per cent.; and for sprinkling: P 3 0-4 per cent.; P 23 0-3
to 0-4 per cent.; P 21 0-75 per cent.; P 15 0-75 per cent.

The remaining three preparations with favourable chemothera-
peutical indices, P 8, P 28, and P 10, require to be applied at
comparatively high concentrations and are therefore impracticable
on economic grounds.

Discussing the comparative efficacy of various inorganic and
organic mercury compounds, the author points out that the efficiency
of corrosive sublimate compared with mercuric oxycyanide and
other compounds is connected with the question of dissociation. Of
the organic mercury compounds P 30 combines the simplest con-
struction, CH,—Hg—lI with the utmost efficiency, far exceeding
that of corrosive sublimate. In comparison with this simple com-
bination of the fatty series, the benzene compounds were much less
efficacious. An increased carbon content appears to depress the
activity of the mercury, while the introduction of a carboxyl group
into the mereury compounds produced a similar effect.

P 23, which is constitutionally incapable of dissociation, is
almost equal in efficacy to P 1, and there are various other instances
(e.g. P 25) of fungicidal efficiency in the absence of dissociation.
P 27 and P 22, the structures of which are exceedingly complex,
are of no value for seed disinfection in spite of their high reputation
in the medical world.

In preparations where the sprinkling coefticient B is lower than 1,
the more favourable effect of the sprinkling method is due to the
prolongation of the disinfection process and the increased efficacy
of the preparation owing to the absorption and consequently
augmented concentration of the solution. In preparations with
a high sprinkling coefficient, however, the reduced efficiency is due
to the deprivation of the toxicity of the product by the seed. Ex-
periments showed that the adsorption coefficients of the simple

560

mercury compounds CH,HgI and CH,HgOH were very high;
a portion of the mercury content of the solutions is taken up
by the dead outer layers of the grain and thus rendered innocuous
to the externally adhering fungous spores and to the inner tissues of
the seed.

The fundamental difference between immersion and sprinkling is
that in the former method large quantities of disinfectant are
brought into contact with a relatively small amount of seed and
are thus not noticeably deprived of their toxicity, whereas in the
latter method the potential loss of toxicity is increased with the
diminution of the amount of liquid. The inverse ratios between
the dosis cwrativa and sprinkling coefficient, which indicate that
mercury compounds with a low dosis curativa have a high
sprinkling coefficient and vice versa, are readily explained by the
fact that sprinkled seed deprives efficacious compounds at weak
concentrations of toxicity more completely than inferior fungicides
at high concentrations.

In discussing the importance of having a relatively high dosis
toxica in obtaining a low chemotherapeutical index, the author
points out that only those fungicides can exercise a toxic action on
the seed which penetrate to the interior, after traversing the dead
outer layers of the pericarp and testa, which, as stated above, adsorb
a certain amount of the solution. Thus the liquid first reaches the
interior as an innocuous solution; it is only after protraction of
the process or an inerease of the concentration, resulting in a
saturation of the outer layers with the fungicide, that the toxic
solution penetrates the seed and the dosis toxvcw is reached.

An ideal fungicide should contain as little mereury as possible,
have the lowest possible chemotherapeutical index, and be equally
efficient both in immersion and sprinkling. The two first require-
ments are mutually compatible, but not the third, since the same
cause which results in the favourable chemotherapeutical index
removes the sprinkling coefficient farther away from 1] in an upward
direction. Disinfectants which have to be applied at a ten times
higher strength for sprinkling than for immersion are impracticable
owing to the impossibility of securing the necessary exactitude on
a large agricultural scale. :

It has already been shown [see preceding abstract | that formalin
combines a very unfavourable chemotherapeutical index (1-3) with
a strikingly low sprinkling coefficient (0-5). Chromic acid behaves
similarly, while ammoniacal copper oxide and sulphuric acid unite
a very low chemotherapeutical index with an extremely high
sprinkling coefficient.

DurRENoy (J.). Iba transmission des maladies des plantes par
voie biologique. [The transmission of plant diseases by bio-
logical means.|— Reprint of a paper read before the Soczété de
Pathologie comparée on 10th April, 1923, 8 pp., 2 figs., 1923.

The author reviews the various biological means of transmission
of plant diseases, dealing briefly with cases where one parasite
opens the way to another by simple wounding of the host tissues.

Wounds caused by cutting tools act in a similar manner, but in

these cases the parasitic organism may be inoculated at the same

561

time, if the implement has previously been used on diseased plants.
Both man and domestic or wild animals may carry diseases con-
siderable distances, the former on clothing and boots, and the latter
on pelt, hoofs, and the like. An equally important source of infec-
tion is the alimentary canal of animals, Fusariwm wilt of melon
(F. solani), for instance, being often transmitted through larval
faeces. In the soil, nematodes and other insects transport bacteria
and spores from one root to another.

The relationship of predatory animals to cryptogamic organisms
is frequently made closer by the predilection of the former for para-
sitized tissues.’ Thus, in the American pine forests squirrels are
fond of gnawing the tumours produced by a species of Peridermiwm,
the spores of which are inoculated into healthy pines subsequently
attacked by these animals.. Many insects have a preference for
galls and tumours on account of their succulent tissues. Cases of
infection have been traced to the symbiotic relationship existing
between insects and fungi (i.e. Xyleborus dispur always carries in
its pharynx Moniliw candida, which grows in its bore holes and on
which it flourishes) and even ordinary soil organisms, such as
Bacillus mycoides, have been isolated from tumours, a species of
Chermes being responsible for the transmission of the organism,
thus indicating that a pathogen need not necessarily be obtained
from a diseased plant.

But beyond being a simple carrier of, or living in symbiosis with,
a parasitic organism, an insect may form with the plant an alterna-
tive host, in which the parasite completes its life cycle. The incu-
bation period sometimes necessary for the transmission of diseases
of the mosaic type suggests this possibility.

’ Informazioni | Notes.|—Boll. mensile R. Staz. Pat. veg., iv, 1-3,

pp. 138-31, 1923.

Mancini in the Coltivatore of November—December, 1922, pub-
lishes the results of his investigations into a malformation (‘ ginoec-
chiatura’) of the ears of wheat, which, however, only occurs rarely
and is of little economic importance. The most usual symptom is
a kink in the last sheath below the ligular collar and plants affected
become severely deformed. In affected ears a certain sterility of
the flowers is found to occur, especially in the portion above and in
that immediately below the kink in the unexpanded ear. The
weight of individual grains in deformed ears is slightly higher than
normal, but this is largely compensated by their small numbers due
to the sterility of the flowers. The author’s opinion is that the
trouble is due to traumatic causes produced by strong winds, and
experiments with some varieties of Todaro on soil heavily treated
with stable manure have demonstrated that trophic conditions have
a great influence on the disease. It has been found possible to
reproduce the disease by bending the last sheath, before the ear
emerges. The author has also noted a singular malformation in
certain late varieties of grain, characterized by twisted and

shortened ears and by an undulating or zigzagging rachis, which he

thinks is due to unduly accelerated and disharmonious growth in
the last stages of development.
In the Giornale d Agricoltura della Domenica of 4th February,

562

1923, Boni gives an account of tests carried out with lime-sulphur
(20° Baumé diluted to 60-80 per cent. strength) in the winter
treatment of fruit trees. The results are stated to have been
satisfactory so far as apple mildew is concerned.

Gramatica in the Trentino province, and Topi in that of Senese,
have carried out tests with copper preparations for the control of
the vine Peronospora |Plasmopara viticola], which they discuss in
the February number of Italia agricola. The first-named author
obtained poor results with De Haen’s colloidal copper in 1 per cent.
solutions, as well as with List’s of 0-5 per cent. strength, and he
ascribes the failure to the minute quantities of copper contained in
these preparations. Topi experimented with ‘ Nosperal’, prepared
by Meister, Lucius, [and Briining|, of Hoechst [see this Review, ii,
p- 223], which contains copper in combination with resin and is sold
in the form of a very fine, grey powder. This is dissolved in water
in the proportion of 1: 1000 and 0-5 per cent. lime is added. The
results were satisfactory, but not more so than those obtained with
ordinary Bordeaux mixture.

SEAVER (F. J.). Mycological work in Porto Rico and the Virgin
Islands.—Journ. New York Bot. Gard., xxiv, 281, pp. 99-101,
1923.

A brief account is given of a ten weeks’ visit paid by the author
to Porto Rico and the Virgin Islands at the request of the Insular
Government to study the fungi of these Islands, more especially
those which attack coffee and citrus crops. In 1918 a summary of
the mycological work carried out in Porto Rico appeared in the form
of a check list of the local fungi (Jowrn. Dept. Agric. Porto Rico,
ii, 3, 1918) and this work is at present being extended and revised
by the writer and Mr. C. E. Chardon, Sugar Expert at the Insular
Experiment Station.

Altogether, over a thousand fungi were collected, a considerable
number of which are new to science, and detailed reports of the
results of microscopical examination of the new material will be
published in due course. Particular interest attaches to the speci-
mens collected in the Virgin Islands owing to the scarcity of the
information on the subject hitherto available.

Morstatr (H.). Einf hrung in die Pflanzenpathologie. Ein
Lehrbuch fir Land- und Forstwirte, Gartner und Biologen.
[Introduction to Plant Pathology. A textbook for agri- and
sylviculturists, gardeners and biologists.|—Sammlung Born-
traeger, i, Berlin, 159 pp., 4 figs., 1923.

The present little volume is the first to appear of a series in
course of publication in Berlin under the title ‘Sammlung Born-
traeger’, the purpose of which is to supply students and practical
workers in a compact but yet strictly scientific form with outlines
and general principles of various branches of natural science. In
its preface the aim of the author is stated to be to attempt to unite
applied botany in its relation to plant diseases with economic
entomology in a single branch of applied biology.

The book is divided into four chapters, namely: 1. Identification
of plant diseases; 2. Etiology of plant diseases; 3. Causes of plant

563

diseases; 4. Plant protection. The compilation is well arranged
and clearly written, and the discussions on the pathological
anatomy and physiology of plants in chapter II are of particular
interest.

FERDINANDSEN (C.) Ukrudtets Betydning for plantesygdomme.
[The. importance of weeds in plant diseases.]J—Tidsskr. for
Landgkonomi, 6, pp. 265-278, 1923.

In the first section of this paper the author quotes a number of
statistics illustrating the part played by weeds in depriving culti-
vated plants of their proper share of water, potassium, phosphorus,
nitrogen, and other nutrient constituents of the soil. The utility of
weeds as cover crops is also briefly explained.

The second section is devoted to a discussion of weeds as carriers
of infectious plant diseases. Clover, cereal, and other crops culti-
vated near railway banks, roadsides, chalk pits, or waste ground
are readily attacked by fungous diseases, which originate on the
related wild hosts. In many cases, however, the causal organism
has been introduced with cultivated plants from abroad and thence
spread to the wild indigenous hosts, e. g. gooseberry mildew (Sp/liaero-
theca mors-uvae) and oak mildew (Microsphaera alphitoides) [M.
quercina}|. The cabbage fungi Pythiwm de Baryanwm, Cysto-
pus candidus, and Plasmodiphoru brassicae were certainly already
present on their wild hosts at the remote epoch when cabbage was
introduced into Denmark. Recent investigations have shown that
Cystopus candidus is divided into several biological strains, the
spores from radishes being capable of infecting only 50 per cent.
of the inoculated mustard plants and 1 per cent. of cabbage
seedlings.

Both Peronospora schachtii and Uronyces betae are found on the
wild beet; Hypochnus solani occurs on chickweed, &e.: Puccinia
graminis spreads from various wild grasses to rye and oats.
Certain species of juniper are indispensable to the development
of Gymnosporangiwm on apple and pear trees: Puccinia pring-
sheitmiana requires the proximity of various species of Carex to
complete its life cycle. Wart disease (Synchtriwm endobioticum),
powdery scab (Spongospora subterranea), and leaf roll disease of
potatoes are all transmissible to deadly nightshade.

NARASIMHAN (M.J.). Casein as an adhesive in spraying against
Areca koleroga.—Reprinted from Jowrn. Mysore Agric. &
Exper. Union, v, 1, 4 pp., 1923.

For the last twelve years the resin-soda-Bordeaux mixture
(5-5-24 plus 2 |b. resin and 1 lb. soda heated in 1 gall. water) has
been used with success in the control of the ‘koleroga’ disease
Phytophthora wrecae| of the areca palm [| Areca catechw| in Mysore
see this Review, li, p. 22}.

Experiments were conducted in the laboratory to ascertain the
efficacy of casein as a substitute for resin-soda. The Bordeaux
mixture was first prepared in the usual way. To 24 galls. of this
mixture was added 1 gall. of solution containing 0-5 lb. of casein
and 0-51b. of lime. Glass plates were sprayed with resin-soda-
Bordeaux and casein-Bordeaux, dried in an oven, and then placed

‘.

564

under an artificial shower of water for eight days. On re-drying,
the casein-Bordeaux was found to be still intact on the plates while
the resin-soda- Bordeaux showed signs of washing off. In the field
casein spraying was tried in areas where the rainfall varied from
100 to 300 inches, the operation being carried out in June and July
while the nuts were immature. The results of the tests were very
satisfactory, the incidence of the disease on the sprayed trees being
very low indeed. The occasional instances of infection were chiefly
found in areas where showers of rain had fallen soon after the
application of the mixture. The use of 0-25 lb. of casein appears to
give as good results as that of 0-5 lb.

Casein possesses several advantages over resin-soda. It is easier
to use and is readily obtainable in the Bangalore and Kolar districts,
while resin-soda has to be imported. Owing to the smaller quanti-
ties required, the cost of the spraying is reduced by one rupee per
acre.

Casein-Bordeaux forms a less conspicuous coating on the nuts
than the resin-soda-Bordeaux, partly on account of its natural
bluish colour and also because of its very fine spreading qualities.
The film adhering to the surface can, however, be clearly seen even
after the heavy rains.

Weimer (J. L.) & Harter (L, L.). Temperature relations of
eleven species of Rhizopus.—Jowrn. Agric. Res., xxiv, |,
pp. 1-39, 23 graphs, 1923.

It has previously been shown, in connexion with the soft rot of
sweet potatoes produced by various species of Rhizopus [see this
Review, i, p. 272] that temperature played an important part in the
process of infection. The fungi were placed roughly in high, low,
and intermediate temperature groups. In the present paper the
effect of temperatures on the spore germination, mycelial growth,
and fruiting of eleven species of Rhizopus is discussed. These
species fall into three groups as regards their response to tempera-
ture, the time required for germination to begin (i.e. the hours
necessary for germ-tubes to reach the length of the diameter of the
spores) being used as the measure of the influence of the tempera-
ture. R. chinensis has maximum and optimum temperatures higher
than any of the other species (52° and 43° to 45° C. respectively) ;
R. nigricans, microsporus, reflecus, and artocarpi constitute a group
having low optima (nigricans and microsporus 26° to 28°, reflexus
30° to 32°, artocarpi 26° to 29°) and a low maximum (34°, 38°, and
34-5° respectively); while R. tritici, nodosus, delemar, oryzae,
arrhizus, and maidis form an intermediate group (optimum 36° to
38°, maximum 45-5°). Discussing the results obtained, the authors
point out that the cardinal temperatures for spore germination,
growth, and fruiting of the fungi studied vary somewhat. In
general, spores will germinate at a temperature too low for mycelial
growth, and a higher temperature is required for fruiting than for
growth. The optimum for germination is always higher than that
for growth and fruiting, while in most cases the optimum for fruit-
ing is about the same as that for growth. The optimum for fruiting
is often not so well defined as that for growth, and the latter less so
than for spore germination. In each case there is a gradation

565

from the maximum at which the spores will germinate to that
at which fruiting will take place, the maximum for growth
being about midway between that for germination and that for
fruiting.

The effect of temperature on the continued growth of the germ-
tubes was next studied. This was done by measuring the daily
growth increment in Petri dishes. Graphs are given (the growth
being plotted against temperature) of the eleven species. The
minimum temperature for growth varies with the time for the first
5 to 15 days according to the species, after which the true minimum,
below which growth will not take place regardless of time, is
reached. With reference to the maximum temperature, although the
graphs appear to indicate that this did not change, very careful
measurement showed that a so-called shifting of the maximum did
occur in some cases. Most of the fungi appeared to reach their
maximum rates of growth during the second 24-hour period.

The results of experiments on the influence of temperature on
fruiting showed that this takes place over a considerable tempera-
ture range. The optimum for some species is sharp and easily
determined, while in others it extends over several degrees. Tables
are given of the maximum, optimum, and minimum temperatures
for spore germination, mycelial growth, and fruiting for each of the
eleven species studied.

Further studies were made concerning certain environmental
factors influencing germination and growth. The temperature at
which the spores are produced influences in some degree the rate of
germination and the early period of the growth of the resulting
mycelium. Spores of R. nigricans produced at 10° C. germinated
in 30 minutes less time than those formed at 20° and 26°. Spores
of this species from different cultures grown under similar con-
ditions germinated equally well up to 20 days irrespective of age.

Spores of R. nigricuns germinated in aconsiderably shorter time
in a nutrient solution than in water. Sweet potato decoction was
the best liquid and string bean agar the best solid medium tried.
In the comparative tests this fungus grew nearly twice as fast on
string bean as on Irish potato agar. The presence of 20 per cent.
dextrose in Irish potato agar changed the cardinal temperatures of
the strains of R. nigricans studied by 1° to 2°C. RK. nigricans,
the most virulent member of this genus, is somewhat limited in its
scope under natural conditions by temperature relations. The
spores in the experiments described in the present paper were
invariably killed at 35° C. and growth was very sparse and slow at
6-5°C. At 1:5° no appreciable development was made on potato
agar in 30 days.

Harter (L. L.) & WEmeER (J. L.). The relation of the enzym
pectinase to infection of Sweet Potatoes by Rhizopus.— Avier.
Journ. of Botany, x, 15, pp. 245-257, 1923.

The cause of soft rot of sweet potatoes in storage has long been
suspected to be Rhizopus nigricans, although the causal relation of
this fungus has hitherto been somewhat difficult to prove. The
authors’ investigations have shown that Rhizopus nigricans cannot
infect sweet potatoes through the unbroken skin, and that infection

566

is only rarely produced by smearing spores and hyphae on a freshly
cut surface. However, when the fungus is given a saprophytic
start by growing on dead rootlets, in synthetic agar solidified on
the cut surface of the potato, or in dead cells charred over a Bunsen
burner, infection readily takes place. It can also be readily in-
duced by growing the organism for a day or two in sweet potato
decoction, the latter, with the mycelium, being poured into a ‘ well’
made in the potato and then sealed over with a cover glass to pre-
vent evaporation. Infection is accomplished only after the dissolu-
tion of the middle lamellae by means of the pectinase secreted in
the growing hyphae [see this Review, ii, p. 418]. This enzyme
appears to be secreted in advance of the growth of the fungus,
a sterile zone always being present between the healthy and myce-
lium-infested regions. In almost ail cases infection takes place in
wounds where the fungus is able to secure a saprophytic start on
some dead tissues. During the growth of the mycelium in these
dead cells, the pectinase is produced which dissolves the middle
lamellae of the living cells of the host. These cells then die and
provide a suitable substance for the further development of the
fungus.

Several other species besides R. nigricuns were found to be
able to cause decay in sweet potatoes, and in every instance the
authors’ experiments were duplicated with R. tritici. All the
species were found to secrete pectinase and to macerate the host
tissue.

The practical significance of these results is that-wounding is
a necessary preliminary to infection. Rough handling during
harvesting, storage, and preparation for market should be avoided
as far as possible.

The titles of 37 references to literature are cited.

Napson (G. A.) & JOLKEVITCH (A. I1.). Spicaria purpurogenes n. sp.
K sompocy 06 antaronusme mukpobos. [Spicaria purpwrogenes
n. sp. On the question of antagonism of microbes.|—Buld.
Chief Bot. Gard. Russian Republic, xxi, Suppl. i, pp. 1-12,
3 col. pl., 1923. .

In one of the authors’ cultures of common bread yeast (Saccharo-
myces cerevisiae) on malt agar a fungous contamination appeared,
probably from the air, which produced a red pigment. The yeast
cells near the fungus were killed and differentially stained as in a
well-made microscopic preparation.

The fungus in question belongs to the genus Spicaria and is
described as a new species S. purpurogenes. The mycelium is about
0-75 p in diameter, septate, profusely branching, forming a weft of
varying thickness according to the conditions of growth. By itself
the mycelium is colourless but may when old become stained with
its own pigment. It grows comparatively slowly, the production
of conidia starting in one to two weeks, or sometimes later, depend-
ing on the cultural conditions: the latter also affect the colour of
the pigment which may be yellowish, brownish, or red.

When about to fructify the mycelium appears to be covered with
a white down. This is formed by nascent conidiophores which are
tree-like and pyramidal in shape, 70 to 175 » high, the branches

567

usually being disposed in whorls. Oblong bodies are generally
detached from the tips of the branches and each of these bodies
subsequently divides into two conidia by constriction in the middle;
in some cases, however, chains of conidia are abstricted from the
tips of the branches. The conidiophores may measure up to 3-75 wu
at the base.

The conidia are elliptical, 1-5 to 2-25 by 2-25 to 3 yw, or occasionally
round. Mature conidia give the fungusa greenish or dove-coloured
appearance. When germinating they swell slightly and produce
1 to 4 germ-tubes.

In older cultures chlamydospores are found. These are elliptical
or round cells with thick, clearly double, shining walls and dense
contents, and are borne on short lateral branches.

Details are given of the cultural characters of the fungus which
appear to show that carbohydrates (sugar or starch) stimulate the
development of the fungus and that they are necessary for the pro-
duction of the red pigment, which is favoured more by glucose than
by saccharose, and by a weak acid than by a weak alkaline medium.
Pigment production was better at 15°C. than at 23°C., but light
had no effect on it.

The authors tested the reciprocal action of S. purpwrogenes and
Saccharomyces cerevisiae by sowing them in parallel or crossed
streaks on agar plates. These tests showed plainly the aggressive
behaviour of the fungus on the yeast, although the latter also
affected the fungus by weakening its growth, suppressing the
production of conidia, and stimulating the production of the red
pigment. The toxicity of the red pigment on the yeast was clearly
manifest, and there is no doubt that the struggle between fungus
and yeast is carried on by chemical substances, by mutual poison-
ing, the advantage lying with the fungus. A transfer of red stained
Spicaria to a fresh dish gives rise to normal unstained or very
slightly stained cultures. The yeast therefore clearly stimulates
the production of pigment. On media lacking carbohydrates the
fungus does not produce the pigment even in the presence of the

east.

: Another species of yeast, Nadsonia elonguta, proved to be even
a weaker antagonist than the former one, although in this case
sporulating cells are frequently seen whereas they were observed
only once in the case of Saccharomyces. The common milk mould,
Oidiuwm lactis, was found to be still more susceptible, and similar
results were obtained with HMndomyces veriulis, a ‘fat yeast’.
Penicillium glaucum was also found to be susceptible to the
Spicaria, being differentially stained by it, even in its young, im-
mature conidia. The use of chemical substances and pigments by
fungi to protect themselves from the aggressive action of other
fungi and bacteria appears to be widely employed and to play an
important part in the biology of micro-organisms.

Miuiarp (W. A.) & Burr (S.). The supposed relation of Potato
skin spot to corky scab.— (Gaurd. Chron., 1xxii, p. 355, 1923.
Shapovalov’s conclusion [see this Review, ii, p. 389] that skin spot
of potatoes [previously referred to Oospora pustulans| is an
immature stage of corky scab [Spongospora subterranea], would,

568

if satisfactorily established, be of considerable importance from
a practical point of view. The pustules of skin spot are uniformly
present on many well-known Scotch and English varieties of seed
potato, including King Edward and Ally, and the prospect of corky
scab being transmitted in this way is very alarming. However, as
a result of thorough investigations on the pathogenicity of Oospora
pustulans, details of which which will be published later, the
authors believe they have obtained overwhelming evidence that
skin spot is caused solely by Oospora pustulans and that it is in no
way related to corky scab.

Une nouvelle maladie de la Pomme de terre. [A new Potato
disease. ].—Bull. Agric. Algérie-Tunisie-Maroe, xxix, 2nd ser.,
4, p. 69, 1923.

The article reports the observation of Spongospora subterranea
on potatoes in the coastal district of Algeria, and states that the
disease is new to Algeria. No great losses are anticipated from
this source as climatic conditions are rarely favourable to the
development of the trouble, but brief instructions are given for pre-
venting its spread. ;

Perret (C.). a dégénérescence des Pommes de terre. [|The
degeneration of Potatoes.]—La Vie agric., xxiu, 30, pp. 61-66,
6 figs., 1923.

During 1921 and 1922 the author carried out a series of investiga-
tions at the Merle (Loire) Experiment Station which furnished
some data in connexion with leaf roll and other virus diseases of
potatoes. ;

Early in 1921 a sack containing the tubers harvested from two
pure line plants of the Paul Kruger [President] variety (susceptible
to leaf roll) was supplied by Professor Quanjer to the Merle Ex-
periment Station. Six of these tubers were each cut in two and
the sections numbered 1 and 1’, 2 and 2’, &c. The halves 1 to 6
were planted in a field formerly under clover at a distance of 10
metres from other potatoes, in April 1921, and the corresponding
sections 1’ to 6’ interspersed among plants of Institut de Beauvais
suffering severely from leaf roll. The resulting plants in both plots
were healthy and vigorous, but towards the end of August those in
the vicinity of the diseased Institut de Beauvais began to show signs
of leaf roll. The yield. however, was not reduced, and it was thought
that the symptoms might be due to drought. In order to settle
this point the tubers from each plot were kept separate, the crop
from the tubers 1’ to 6’ being sent to the Grignon Experiment
Station and those from the series 1 to 6 retained at Merle. In 1922
the plants grown from the latter were all healthy while those from
the tubers |’ to 6’ showed, with one exception, the typical symptoms
of leaf roll. There seems, therefore, to be no doubt that infection
was actually transmitted from the diseased Institut de Beauvais
plants to the Paul Kruger plants.

Discussing the difficulty of accurately diagnosing leaf roll on
account of the similarity of the symptoms to those produced by
Rhizoctonia, blackleg { Bacillus atrosepticus|, basal injuries, prema-
ture desiccation, and other causes, the author recommends the use

569

of the iodine water test. The leaves of suspected plants should be
gathered in the early morning, boiled in Eau de Javélle, rinsed in
ordinary water, dipped into water containing a few drops of iodine,
and rinsed again. The leaves of diseased plants show a dark brown
discoloration owing to the accumulation of starch. Leaves detached
in the evening and placed overnight with the petioles in water
retain their starch if diseased and lose it if healthy. According to
Murphy [see this Review, i, p. 306] the results of this reaction are
nearly always positive in cases of secondary leaf roll.

The part played by aphids in the transmission of virus diseases
is briefly discussed, no original theories, however, being advanced.
The effect of altitude on the incidence of these diseases has been
studied in the Loire Department, but the investigations are com-
plicated by the different reaction of certain varieties to high and
low-lying situations. Thus, at 400m. above sea-level the per-
centage of leaf roll among Institut de Beauvais potatoes increases
from 80 to 90 in three years. On the other hand, Violette du Forez
has been cultivated for fifty years in the mountains at an elevation
of 1,000 to 1,200 m., and Merveille d’Amérique which ‘ degenerates’
at 400 m. seems to recover in the mountains.

The method of field inspection adopted in the Loire Department
is outlined. No field of Violette du Forez potatoes containing more
than eight defective plants out of forty is passed. Excellent results
are stated to have been obtained during the last three years by this
method and the scope of the inspection is now to be extended by
the Departmental Agricultural Bureau.

ARTSCHWAGER (E. F.). Occurrence and significance of phloem
necrosis in the Irish Potato.— Journ. Agric. Res., xxiv, 3, pp.
237-245, 6 pl., 3 figs., 1923.

Since 1916 the author has carried out investigations on the
phloem of a large number of cultivated and indigenous South
American varieties of potatoes in order to arrive at some definite
basis as to what constitutes a healthy potato plant from the
anatomical point of view and under what conditions the phloem
will remain normal. To guard against erroneous diagnoses in the
case of certain diseases, such as leaf roll, it is necessary to
distinguish between normal histological changes and induced
abnormal states, the latter alone being truly pathological.

The vascular tissue of the potato plant shows a bicollateral
arrangement of its elements which is most clearly seen in the
larger stem bundles. The primary phloem external to the
cambium is composed of small groups of more or less continuous
cells, but the groups constituting the inner phloem are very
variable in size and scattered. Later secondary phloem elements
become differentiated and participate in the translocation processes ;
the primary phloem groups remain active until the plant is mature.
Apart from a slight thickening of the cell walls and occasional
callus deposits on the plates of the sieve-tubes, there are no notice-
able characteristic structural or chemical changes in the phloem of
the mature plant.

Local necrotic changes in the parenchymatous tissue, however,
due to a variety of causes, may be observed in any potato plant.

570

The study of numerous varieties at the Fort Lewis high altitude
station, Colorado, revealed the influence of ecological factors on
anatomical modifications in the vascular tissue. Thus, a super-
abundance of water induced a discoloration of the secondary
elements of the wood and the primary xylem, the lumina being
filled with a brown, gummy deposit. A greatly reduced water
supply, or alternate wetting and drying, produced a dense and more
strongly lignified wood. Shading reduced the xylem and the
lignification of the cells was less pronounced. The occurence of
these and other changes of a purely environmental character must
not be confused with true pathological modifications.

External insect injuries frequently cause internal stem lesions
and a dark discoloration of the tissues. In extreme cases entire
cells or cell groups may be obliterated.

In connexion with the stem streak disease [see this Reviev, ii, p.
285] severe necrosis may be observed both in the inner and outer
phloem, the cells being brownish in colour and the lumina may be
partly closed by the pressure of the surrounding cells. The necrotic
phloem groups, however, show no regularity either in vertical or
lateral distribution and it remains to be seen whether this disease
is definitely connected with leaf roll.

Stem sections of a typical leaf roll plant exhibit, as a diagnostic
internal symptom, a necrosis and lignification of the phloem groups,
which is described in some detail. When severe external symptoms
are apparent the diseased groups pervade the entire plant, with
the occasional exception of the underground organs. The distal
stem region is commonly severely affected, and the basal stem
region always shows necrosis when the symptoms appear early.
The nodal tissues are more severely attacked than the internodal
ones, especially in the early stages of the disease.

In the petiole and midrib necrosis may appear later but is usually
correlated with the severity of the rolling. In the underground
organs of diseased plants the phloem strands are usually normal but
may show necrosis in bad cases.

The lateral distribution of phloem-necrosis is subject to a great
deal of variation. Perfectly healthy phloem groups are often seen
side by side with diseased ones. In the apical stem region, the
first stages of necrosis are found in the external phloem and only
later in both regions. In the base of the stem both inner and outer
phloem may be attacked, but often the inner is completely de-
stroyed whilst the outer remains healthy.

Before there is any apparent evidence of lignification of the
phloem tissue, the development of the vascular tissue in the distal
stem region shows a deviation from its normal course, represented
by an irregular maturing of the xylem. Close examination of
sections stained with phloroglucin and hydrochloric acid reveals
a slight degree of lignification in parts of the walls of the phloem
cells centrifugal to the depression in the cambium. The cells of the
pericycle in this region have a greater radial diameter than the
normal. The first cells to show lignification are usually those
adjacent to the fibres, but occasionally lignification may start at
the centre of a phloem group and extend centrifugally.

Prior to lignitication of the phloem, a swelling of the walls of the

571

diseased cells extends centrifugally from the fibres. Large
quantities of pectic substances in these walls are indicated by the
deep blue colour imparted at this stage by ferrous sulphate and
potassium ferrocyanide. Gradual lignification of the cells ensues,
and in severe cases most or all of the primary phloem is destroyed.
The intercellular spaces formed by the separation of the primary
walls of adjacent cells become filled with a brown deposit, which at
a certain stage takes the lignin stain. Following the gradual
degeneration of the cells and subsequent loss of turgor, the phloem
elements collapse unless rapid lignification lends rigidity to the
walls.

Obliteration of the phloem is constantly associated with leaf roll,
and Quanjer (Meded. R. Hoog. Land-, Tuin, en Boschbowwsch. ;
Wageningen, vi, p. 41, 1913) regards it as an infallible symptom of
that disease. It is, however, also a concomitant of various other
disturbances, and its value as a diagnostic internal symptom in leaf
roll depends less on its mere presence than on its universal distribu-
tion and the absence of necrosis in other tissues.

Borses (J. O.). Onbekende Factoren bij het kweeken van
ziektevrij pootgoed. {Unknown factors in the propagation of
disease-free seed.|—Tijdschr. over Plantenziekten, xxix, 7,
pp. 113-126, 1923.

The possibility of regenerating, by means of judicious selection,
some of the more important potato varieties is discussed.
Encouraging results in this direction have been obtained in Fries-
land with the Eigenheimer variety, and in several different localities
with Roode Star, Bravo, and Zeeuwsche Blauwe. In Germany
several growers have succeeded in selecting resistant strains of the
‘degenerating’ Industrie variety. There are, however, limits to
the efficacy of this method, as has been shown by the repeated
failure of attempts to cultivate the Eigenheimer and Paul Kruger
[President] varieties in the sandy soil of the Veen Colony districts.
The latter variety is fast losing its commercial importance owing to
the difficulty of growing it on a large scale. For breeding purposes,
however, it is very valuable, and in a recent series of hybridization
experiments the best product was obtained from a cross between
Franschen and Paul Kruger.

With reference to the transmission of the so-called ‘degeneration’
diseases, the author investigated the possibility of their being trans-
mitted, in the absence of potatoes, from weeds or other plants, by
the following experiment which he carried out in 1920.

He divided each of four potato tubers into six parts and planted
them in six plots, one part of each potato in each plot, in an
enclosed garden containing no other potatoes or Solanaceae. Six of
the progeny from these developed leaf roll, and one mosaic. The
diseased plants came from different tubers, so that infection very
probably did not originate in the seed tuber and was more likely
to be due to some external cause. The author considers that the
virus probably originated from other plants (not Solanaceous) in
the garden.

The importance of early digging of seed tubers, based on the
theory that the mosaic virus spreads from the plant to the tuber

572

[see this Review, ii. p. 519] is discussed. With early-ripening
varieties this method is quite practicable, but in a late-maturing
variety, e. g. Paul Kruger, the tubers are too small for digging in
the middle of June (the critical time for infection). Possibly the
removal of the foliage would serve the same purpose, since the
object of early digging is to sever the connexion between the in-
fected leaves and the tubers. The actual degree of maturity of the
tubers at the time of digging is a secondary consideration.

Dorst (J. C.). Aantasting van de Aardappelplant door Rhizoc-
tonia solani en haar bestrijding door sublimaat. [The infec-
tion of the Potato by Rhizoctonia solani and its control by
corrosive sublimate.]|—Tijdschr. over Plantenziekten, xxix, 6,
pp. 97-106, 1923.

The symptoms and distribution of the Rhizoctonia disease of
potatoes, caused by R. solani, are described. The incidence of the
disease in Holland is stated to be very heavy on the varieties
Eersteling, Midlothian Early, Schotsche Muis, Geeltjes, Eigenheimer,
and Zeeuwsche Blauwe, but whether this is due to the inherent
_ susceptibility of these varieties or to their continual cultivation on
infected soil is difficult to determine. The disease is very prevalent
in Holland on sandy clay soil and on reclaimed pasture land. A
striking feature of the crops grown in the latter type of soil is the
tendency to tuber formation above the ground. The application of
fresh organic manure appears to increase the incidence of the
disease.

The eradication of the causal organism from the soil can only be
gradually accomplished by suitable crop rotation, by the removal
of weeds and potato refuse, and by seed disinfection. The latter
can be thoroughly effected by immersion for one hour and a half in
a solution of 1 per cent. corrosive sublimate (0-5 hl. to 1 hl. of pota-
toes). The temperature of the water used in the solution should
not be lower than 5° C. or injuries to the tubers may result, Ex-
cellent results have been obtained in Friesland by disinfection
with corrosive sublimate, the advantages of which are briefly
described.

De Lona (W. A). Sulphur and soil acidity.—Scient. Agric., iii, 10,
pp. 354-356, 1923.

It has been definitely shown that the development of potato
scab [ Actinomyces scabies] can be controlled by the application of
sulphur to the soil. In order to determine the requirements for
optimum results from this method of treatment under Nova Scotia
conditions, investigations were undertaken at the Truro Agricultural
College on the effects of the application to infested soil of 300, 400,
500, and 600 lb. of sulphur per acre. The sulphur was applied at
three different periods, namely, four weeks before, during, and four
weeks after planting the potatoes. The inoculated form of sulphur
[see this Review, i, p. 82] was chiefly used, but for comparative pur-
poses a series of the same amounts of flowers of sulphur applied at
the time of planting was included. The experiment recorded in
this paper was started in boxes in the greenhouses in January
1922, although field experiments are also being carried out. The

573

soil in the boxes was fertilized at the rate of 500 lb. per acre with
a 4-8-4 mixture composed of nitrate of soda, acid phosphate, and
muriate of potash. The sulphur applied was thoroughly mixed
with the top four inches of soil.

The results of monthly determinations of the lime requirements
showed a marked increase of acidity in all cases where sulphur was
applied. Up to 5001b. the amount of acidity produced increased
with the quantity of sulphur applied, beyond this amount the
results were conflicting, an increase of the lime requirement some-
times being produced and sometimes not. The uninoculated form
produced as much acidity as the inoculated. The maximum lime
requirement was obtained in every case at the second test, namely,
about eight weeks after the planting of the potato setts.

Since the control boxes were treated in all respects similarly to
the others, except for the absence of sulphur, it appears reasonable
to conclude that the increase of acidity shown by the increased
lime requirement was due, directly or indirectly, to the application
of the sulphur.

The actual increase in lime requirement was found to be largely
in excess of that expected theoretically, even supposing the whole
of the sulphur to be oxidized to sulphuric acid. The sulphur may
have caused the plants to produce more acid, or there may be some
stimulation of the bacterial population of the soil. Of these pos-
sibilities the second seems to be the most promising and is supported
by the work of others, although further investigation is necessary
before the matter can be cleared up.

Rosa (J. T., Jr.). Spraying Irish Potatoes.— Missouri Agric.
Exper. Stat. Bull., 198, 8 pp., 2 figs., 1923.

Spraying potatoes with Bordeaux mixture has not yet become
general in Missouri, probably owing to the relative scarcity of early
and late blight [Alternaria solani and Phytophthora infestans] in
the spring and early summer. In other States experiments have
shown that proper spraying with Bordeaux generally increases
yields even when these diseases are absent.

Experiments with the varieties Early Ohio in 1921, and Irish
Cobbler in 1921 and 1922, at Columbia, are described in this paper,
which indicate the beneficial action of such sprays in the preven-
tion of tipburn and hopperburn. A serious objection to the spray-
ing of the Early Ohio variety with Bordeaux mixture is the
formation of second growths on the tubers [see this Review, ii, p.
466]. This objection, however, does not apply in the case of Irish
Cobbler. In 1922 spraying this variety four times, when the
plants were four to six inches in height, with lead arsenate alone
and with Bordeaux plus lead arsenate, gave increased yields of 21-2
and 123-6 per cent., respectively, over the control. Leaf hoppers
became abundant at the end of June, and severe burning appeared
early in July on the unsprayed plants. The increased yield is
probably due almost entirely to tuber growth made by the sprayed
plants after the untreated controls have begun to die. Thus by
digging comparatively late (August) a considerably larger crop
can be obtained from the sprayed plants.

574

KOHLER (E.). Ueber den derzeitigen Stand der Erforschung des
Kartoffelkrebses. [On the present position of research on
wart disease of the Potato.|—Arb. Biol. Reichsanst. fiir Land-
und Forstwirtsch., xi, 4, pp. 289-313, 2 pL, 19238.

In this paper the author gives a detailed resumé of the present
knowledge regarding wart disease (Synchytrium endobioticum), in-
cluding its distribution, life-history, and symptoms, and incidentally
adds the results of his own investigations of this disease. His
series of experiments on the development and cytology of the
organism, while differing in certain aspects, agreed in the main with
those obtained by Miss Curtis [see this Review, i, p. 80]. The main
points of difference may be summarized as follows. According to
the author, the first extrusion of chromatin from the nucleolus into
the nuclear cavity of prosoral nuclei is effected solely by means of
the linin network, which stains exactly like the nucleolus. The
linin network does not become detached from the nucleolus until
the extrusion of granules of chromatin into the nuclear cavity
has been affected. In the final stages the linin network is visible
only as a structure devoid of chromatin (the ‘amoeboid body’ of
Percival), which remains until the division of the primary nucleus,
or dissolves and becomes dispersed in the nuclear cavity. Both
resting sporangia and prosori were observed to contain ‘amoeboid
bodies *. In subsequent extrusions the chromatin is exuded drop by
drop from the nucleolus and absorbed by the linin network of the
nuclear space.

According to Miss Curtis the full complement of nuclei of the
prosorus at the time of cleavage and after mitosis has taken place
is about 32, but the author observed a considerably larger number.
As regards the fate of the chromatin immediately after its extrusion
from the nucleus of the resting sporangium the author differs
from Miss Curtis. According to him the chromidia extruded into the
protoplasm swell owing to the formation of one or more vacuoles
which increase considerably in size, and the actual chromidial
substance is finally concentrated in a somewhat thin, irregular
layer at the periphery of the vacuoles. This layer is ruptured by
the progressive increase of the latter and the chromidial mass
divided into irregular fragments which are further disintegrated
into fine granules and are then distributed in the protoplasm. The
fusion of the zoospores was not observed by the author.

In 1922 the author carried out an experiment on the resistant
Citrus potato variety, the results of which showed that the degree
of infection decreased as the size of the tubers increased. Tubers
weighing over 40 gm. were not attacked, and even on the smaller
tubers the warts were no larger than a pea, in spite of the presence
of numerous summer sori. Further observations on the Adonis
variety, on which the warts were also small, indicated that the
parasite flourishes independently of abnormal cell division in the
affected tissues. It is highly probable that susceptible varieties
exert some powerful attraction, the nature of which is obscure,
which induces the zoospore to penetrate the epidermis. Conversely,
immune varieties appear to owe their freedom from the disease to
the absence of this specific attraction.

575

By means of pure line selection, immune types of the varieties
Tannenberg, Wohlgeschmack, and Romaner were obtained.

Further investigations were made on the causes which bring
about immunity, but the results were chiefly negative. Dealing
first with the colour of the sprouts, the author divided potatoes into
the three following groups, according to this character. 1. Those
with green sprouts (without anthocyanin). 2. Those with predomin-
antly reddish-purple anthocyanin (denoting an acid reaction of the
cell sap). 3. Those with predominantly bluish-purple anthocyanin
(denoting an alkaline reaction of the cell sap). There appeared,
however, to be no correlation between the potatoes in these various
groups and immunity.

It was also ascertained by means of experiments with susceptible,
resistant, and immune varieties that there was no connexion between
the solanin content of the various organs and susceptibility to, or
immunity from, the disease. It was thought that the hydrogen-
ion concentration of the epidermal cells might have an important
bearing on immunity and susceptibility. In order to test this
hypothesis it was necessary to find an indicator which could be
absorbed by the living cells. Neutral red was found to be the only
colour indicator thus absorbed and it was found that both suscep-
tible and immune varieties took on a similar coloration.

Regarding the control of the disease, the author is of the opinion
that the use of immune varieties is the only practical solution, and
lists eight German varieties which are immune, as well as various
English and American immunes. He summarizes very fully the
evidence at present available on the attempts at sterilizing soil
infected with the parasite.

There are numerous references to the work of previous investi-
gators and a bibliography is appended.

ScHANDER & RICHTER. Ueber den Nachweis von Dauersporen
von Chrysophlyctis endobiotica Schilb. (Kartoffelkrebs) in
der den Kartoffeln anhaftenden Erde, |The detection of
resting spores of Chrysophlyctis endobiotica Schilb. (Potato
wart disease) in the soil adhering to Potatoes.|—Centralbl. fiir
Bakt., Ab. 2, lviii, 19-24, pp. 454-461, 1923.

The increasing prevalence of wart disease of potatoes, caused by
the fungus Chrysophlyctis endobiotica [Synchytrium endobioticwm |,
in Germany necessitates the immediate introduction of a method
whereby the soil particles adhering to potato consignments can be
rapidiy and thoroughly inspected for the presence of the causal
organism.

The results of a preliminary series of experiments showed that
direct microscopical examination of the soil was not a reliable
method when the proportion of soil to diseased tissue from the
excrescences was 100 to 1, since spores were easily concealed by
the larger particles. The possibility that the specific weight of
the spores might be less than that of soil particles of the same
size suggested that if spores and soil particles were mixed with
water and stirred, the latter would sink and form a deposit at the
bottom of the tube while the spores floated. This proved to be the
case in a series of tests in which 10 gm. of soil, containing 600 to

576

1,000 spores per gm., were placed in a tube with five times the
amount of water, the proportion of soil to diseased tissue being 100
to 1. After one minute the coarser soil particles had settled and
the liquid above was decanted into a second tube, where it was left
standing for five minutes. Microscopical examination of the sedi-
ment in the second tube revealed the presence of resting spores.
The latter were also present in the liquid after 24 hours’ standing ;
they were extracted by centrifuging and added to those in the
sediment. This was then mixed with a little water and examined
under the microscope ; it was found that one drop contained 10 to
15 spores, which, surrounded by minute soil particles and cell
remains, were easily recognizable. The results of further tests
showed that this method was still reliable when the proportion of
soil to diseased tissue was 2,000 to 1. At this ratio there are 300
to 500 spores of the fungus per kg. of soil, corresponding to 0-5 gm.
or 0-5 ec. of warty tissue.

Suggestions are made regarding the practical application of this
method to the inspection of potato consignments transported by
rail or sea. Not only should the potatoes be superficially inspected
in the vans but a microscopical examination should also be made
if possible from the soil fallen on the floor of the wagons. In
doubtful cases about 50 tubers should be removed to the laboratory
for closer inspection on the lines described above. Should the
decay of the tuber be due to Phytophthora the consignment may
be released, but if there is any trace of wart disease the potatoes
must be taken to the nearest distillery or starch factory |see this
Review, ii, p. 336]. Attention is drawn to the danger of using
vans which have been occupied by infected potatoes for the trans-
port of agricultural implements, live stock, hides, and the like, to
which the spores of the fungus may easily adhere. Such vans
should be disinfected with a 3 per cent. solution of cresol sulphuric
acid and the infected soil and other refuse burnt, buried, or mixed
with a disinfectant.

Percu (T.). A root disease of Hevea (Xylaria thwaitesii
Cooke.)—Trop. Agric., 1x, 2, pp. 100-101, 3 pl., 1928.

In 1921 and 1922 mature Hevea trees were found to be suffering
from a root disease, apparently caused by a Xylaria, which had
previously been recorded only once, in 1910.

On the affected roots the fungus forms black, flat, irregular bands,
sometimes in a network, and extensive patches or plates. The
bands, which appear to result from the fusion of small patches
into a continuous line, are smooth, sometimes longitudinally ridged,
and white internally. They generally exceed 2 mm. in width
and are less than 1 mm, in thickness. A root may be partly
covered with a network of these bands through which the pale
cortex is visible, whilst the remainder is concealed under a con-
tinuous black sheet.

In the early stages of the disease the wood of the roots does not
show any very marked symptoms. In advanced stages, however,
the characteristic features of the disease, which are quite distinet
from those of any other root disease of Hevea, are readily recogniz-
able. When the root is split longitudinally the central region is

577

moist, but still hard, and dark brownish-grey in colour. Outside
this region the wood is drier and yellow-brown in colour, a black
line sometimes separating the two zones. Black lines and ovals
may be present, but are not a constant feature of the disease, as in
Ustulina. The hardness of the discoloured wood is noteworthy.
The inner tissues of the cortex become brown and friable, being
broken down sometimes into fragments united by fine strands of
rubber, but the external layer does not show much alteration.

The fructifications generally appear on the ground near a lateral
root or the collar of the tree. They occur in clusters, arising from
a basal mass in the soil or at ground level. In some cases three or
four stout stalks arise from the basal mass and divide above into
numerous fructifications; in other cases the fructifications all arise
from the same level. They are very variable in shape, up to four
inches in height and one inch in breadth, and have a light brown
outer layer which usually disappears as they mature, leaving a
black surface. They are somewhat corky and white internally.

The appearance of the fructification coincides approximately with
the death of the tree. In all material hitherto found, the fungus
has not been mature, since the infected trees have naturally not
been allowed to remain until the fungus matured. The spores and
perithecia of the fungus are rarely developed in the laboratory, but
in one case this was successfully accomplished, leaving no doubt
that the organism was a Xylaria.

In the first record of this disease the species was referred to as
X. zeylanica, but it would appear from an examination of the type
specimens of Ceylon species of Xylariu in the Kew Herbarium
that its correct name is X. thwaitesi.

RINGOET. a culture de L’Hévéa a la Station agricole de
Yangambi-Gazi (Province orientale) durant l’exercice 1921.
[The cultivation of Hevea at the agricultural Station of Yan-
gambi-Gazi (eastern Province) during 1921.]—Bull. Agric.
Congo Belge, xiv, 1, pp. 8-9, 1923.

Thread disease or streepjeskanker | Phytophthora] and mouldy-
rot [Sphaeronena jimbriatuwm| of Hevea rubber, of which the first
named is more common, are very often found in association. The
damage done in the East Indies by these diseases is considerable,
but in the Belgian Congo the dry climate does not encourage their
development, and cases are not of frequent occurrence. Regular
applications of 5 per cent. agrisol or brunolinum plantarium
solutions are made, and affected trees are given a rest.

Brown bast, though not unknown, has not assumed disquieting
proportions in the Belgian Congo. At the Station, out of a total of
2,342 trees, 344 or 14-7 per cent. are more or less affected. No
treatment has so far been applied, but trees yielding little or no
latex are givenarest. It is hoped to make a trial with hot tar,
which has been successful in Java.

Root diseases are also reported, but have not, as yet, been
identified.

578

Srevens (H. P.). Effect of mould on a sheet Rubber compounded
with litharge.— Bull. Rubber Growers’ Assoc., v, 6, pp. 341-
342, 1923.

A slight retardation in the rate of cure is always noted with
sodium silicofluoride prepared rubber when vulcanizing an ordinary
90-10 test mixing of rubber and sulphur [see this Review, 11, p.
139]. When the minimal proportion of sodium silicofluoride is
used, namely, 1 in 2,000 of latex, the retardation may not exceed
5 per cent., but with larger proportions it may amount to 10 or 15
per cent.

Vuleanizing tests, using the ordinary rubber sulphur 90-10
mixing and the same with the addition of 50 parts of litharge,
have been made with samples of rubber (1) coagulated with acetic
acid and (2) coagulated with sodium silicofluoride (1 Ib. to 150 galls.,
i.e. 1 in 1,500), soaked for half an hour in a saturation of sodium
silicofluoride, drip dried, and smoked as usual. The samples were
packed in a ease exposed to rain for one night. On unpacking the
case a fortnight later the acetic acid coagulated sheet was found to
be covered with mould, whereas the sample coagulated with and
soaked in sodium silicofiuoride was clean.

Tests of the two samples, compounded in one case with sulphur
only and in the second with litharge, showed that in the former
case the acetic acid control cured more rapidly than the sodium
silicofluoride prepared rubber, while with the addition of litharge
the reverse was the case. In the case of the litharged samples the
mouldy condition of the acetic acid prepared sheets probably
accounts for the low rate of cure as compared with that of the
sodium silicofluoride sheets. This reversion in the order of the rate
of cure by the addition of litharge demonstrates the importance of
its inclusion in the tests until a final decision as to the comparative
merits of acetic acid and sodium silicofluoride as coagulants is
reached.

Nortu (D. S.). The control of Sugar-cane diseases.—Reprinted
from Australian Sugar Jowrn., xiv and xv, 46 pp., 19238.

This paper is stated to be the first of a series which will embody
the results of investigations on sugar-cane diseases in Australia
made since 1907, and also of field measures commenced in 1919
with a view to controlling these diseases on lines similar to those
which in Fiji are claimed to have secured such effective control of
‘Fiji disease’ [see this Review, i, p. 187, and ii, p. 288] and other
sugar-cane diseases that they have caused no serious losses in the
crops of that Island of recent years.

In an interesting discussion of the means by which sugar-cane
diseases have reached Australia and Fiji, the author [who is
pathologist to the Colonial Sugar Refining Co.] takes both countries
together, since the free interchange of varieties between them [the
Company having large interests in both areas] has led to their
varieties and diseases being practically identical. Nevertheless,
though certain diseases have undoubtedly been introduced with
interchange of varieties into particular areas, they have not always
succeeded in becoming permanently established there. Fiji disease,
for instance, has never become established at any of the Company's

579

mills in Queensland, though it has been long prevalent and highly
destructive in New South Wales and Fiji; while Sclerosporu
sacchari has not been found in New South Wales, though it occurs
throughout Northern Queensland and Fiji.

The author thinks that Australia has a longer list of serious cane
maladies than any other country, having been more active than
most in introducing new varieties and their diseases from all over
the world. None of the diseases hitherto found is regarded as
endemic, New Guinea, from which many varieties have come, being
considered the home of those Australian diseases of which the
origin has hitherto been obscure. There is stated to be definite
evidence that this is the case with Fiji disease, while Sclerospora
succhari and the hitherto undescribed ‘ leaf scald’ (Bactercwm sp.)
are also suspected to have come from the same source. Little is
known of the sugar-cane diseases of New Guinea, and importations
from that island are held to be exceedingly dangerous.

Much success has attended the efforts to control diseases by the
use of resistant varieties, but the latter appear to have been intro-
duced without due care so that they brought new diseases with
them: each variety was sooner or later attacked in its turn, either
by a new disease or an old one resuscitated. No universally
resistant variety has hitherto been discovered ; Badila appears to be
the nearest approach to a generally resistant cane, but has been
badly damaged by Fiji disease and gumming in certain areas.
Furthermore, the use of resistant canes has often entailed a sacrifice
of yield and quality. Hence the author believes that other methods
of disease control are urgently required in Australia, and he
advocates those that have been tested and found effective in Fiji.
Each disease requires a different treatment, but they may be
grouped to some extent by their salient characters.

The five most virulent cane diseases of Australia constitute
a group characterized by the fact that a diseased cutting will
always produce a diseased plant. They are gumming (bacterium
vascularwm (Cobb) Greig-Smith), leaf scald (Bacteriwm sp.), leaf
stripe [downy mildew] (Sclerospora sacchari Miy.), Fiji disease
[Northiella sacchari Lyon (Phytamoeba sacchari MeWhorter)|, and
mosaic disease. Each of these diseases is also highly infectious by
some aerial (not, so far as is known, soil-borne) means of spread to
other canes in the vicinity. Each is caused by a strict parasite,
unable to thrive for long apart from its living host. Each is
‘incurable’, that is, the infected plant is permanently diseased.
The main source of infection is undoubtedly the use of diseased
stools for ‘seed’. For this group effective control is to be sought
in the measures of field sanitation outlined by the author. The
first of these is ‘seed’ selection, the aim being to avoid the planting
of diseased setts. With gumming and leaf scald, no field in which
infection may reasonably be suspected should be used for seed. For
success in seed selection an exact knowledge of the symptoms is
required, and much use has also been made of the known factors
which influence the occurrence of these diseases, such as the
prevalence of Fiji disease on rich land, of leaf stripe on poor, of
gumming in badly drained areas, of leaf scald on higher, dry land,
and of mosaic in hilly country. The second measure required is

580

the removal of sources of infection by ploughing out badly diseased
fields after harvest and by eradicating all the diseased stools in
milder cases. In widespread outbreaks, as when all the fields of
a farm have become severely infected, such drastic measures are
impracticable, and slower methods, such as the introduction of re-
sistant varieties as an adjunct to seed selection and eradication, must
be adopted. Other measures, applicable to certain diseases only,
are desirable. Such are the avoidance of knife infection with
gumming and leaf scald, improved drainage and cultivation, and
the like. .

In a second group are included red rot (Colletotrichum falcatum
Went), root disease of the type said to be caused by species of
Marasmius, and the sclerotial disease of the leaf sheath. Top rot
[see next abstract], rind disease (Melanconiwm sacchari Massee),
and pineapple disease (Lhielaviopsis paradoxa (de Seynes) v.
Hohnel) may, perhaps, be added to this group, though the two last
apparently only attack parts already dying or dead from other
causes. These are all considered to be due to weak facultative
parasites, capable of persisting on rotten cane or in the soil for
long periods. In soil so contaminated, cane may be severely
attacked under unfavourable conditions for its growth, such as
during periods of drought or floods. These diseases are not
incurable in the sense used above, for a healthy plant may some-
times develop from an infected sett. With them seed selection and
the eradication of diseased plants are measures of secondary value;
the reduction of soil infection by crop rotation, and the use of
resistant varieties are more important, while good cultivation,
manuring, and drainage will also help by promoting a thrifty, even
growth.

In the third group a great variety of leaf spots, such as true rust
| Puccinia kuehnii (Krueger) Butler], eye spot (Cercospora sacchari
van Breda) [? Helminthosporium sacchari Butler], and ring spot
(Leptosphaeria sacchari van Breda), are included. “The majority of
these, though conspicuous, are not usually sufficiently harmful to
warrant special control measures. They mostly appear at a
particular season, such as winter, and disappear later on without
seriously affecting the cane. Occasionally, however, particular
varieties have been badly damaged or even killed by certain of
these diseases, and new varieties have had to be substituted.

Apart from field control, stringent precautions against the
distribution of diseases with cane plants sent from one area to
another are required. The safeguards suggested are: (1) strict
attention at the forwarding end to ensure that only perfectly
healthy plants are sent: (2) planting in quarantine under careful
supervision by a plant pathologist, on receipt, until freedom from
diseases and pests can be guaranteed; (3) raising new varieties at
several different centres within the country from seed, instead of
obtaining them from abroad. Within a particular mill district,
bulk distribution of plants is sometimes necessary to. replace
diseased crops, but this should be carefully controlled by technical
supervision. Foreign importations should be limited to a few
varieties of outstanding promise at long intervals, and a quarantine
of two years should be imposed not only in such cases but usually

581

when plants are sent from state to state within Australia, or even
from one mill district to another unless adjoining and with similar
varieties and diseases. The essentials of an effective system of
quarantining are discussed at some length.

The necessity for such rigid precautions is chiefly due to the fact
that it is impossible to guarantee freedom from disease at the
forwarding end. It has been proved in the case of leaf stripe, Fiji
disease, gumming, and leaf scald that the disease may remain latent
in the growing cane for a long time with no symptoms that can be
detected. Concrete cases in support of this statement are quoted.
Mosaic disease was also widely disseminated with cane importations
before its symptoms were recognized.

The raising of seedling canes in Australia, where little of this
nature has hitherto been effected, is discussed and also the testing
of varieties, special emphasis being laid on the common experience
that diseases are far more prevalent in variety blocks than else-
where, and that experiment stations engaged in variety-testing are
very liable to disseminate diseases. The growing by farmers
of a number of varieties instead of one or two standard canes is
deprecated.

An interesting account is given of the application of the above
considerations to farm practice in the Richmond River district of
New South Wales. Every farm is periodically visited for the
purpose of assisting the farmer in the selection of his seed and the
recognition of diseases present in his crop. Advice is given
regarding suitable varieties to be grown and, when required, on all
matters of cultivation, drainage, and the like, as affecting disease
control. A history of each field is recorded in field plan books which
comprises area, variety, source of seed, incidence of diseases, and
cultivation data. From this information the progress of diseases
from year to year can be followed and steps taken to renew the
stock from safe areas when required. Plot trials are laid out on
a number of farms, planting, weighing, and the like being controlled
by the Company’s scientific staff, and much information as to
the resistance of disease of different varieties is thus being obtained.

Mosaic and Fiji diseases are proving fairly easy to control by
these measures, but gumming and leaf scald have given trouble for
various reasons which delayed the taking of effective measures.
Accurate estimates of the losses from these four diseases in one
mill district gave over 9 per cent. in each of the years 1920 and
1921, estimated on the cane tonnage.

Tryon (H.), Top rot of the Sugar-cane. An inquiry into the
nature and origin of a disease affecting Sugar-cane in the
Herbert River and other districts of Queensland.—()i/ceéiis-
land Bureau of Sugar Experiment Stations. Divn. of Path.
Bull. i, 56 pp., 9 pl., 1923.

The author states that this memoir was written in 1905 but has
not previously been printed, though a summary of it appeared in
the Queensland Agric. Journ., xxi, pp. 498-505, 1906. The work
on which it is based was carried out in 1903, but the disease
appears to have been recorded many years earlier and to have
caused losses in Queensland as far back as 1891.

582

The first external symptom is etiolation of the central shoot of
unexpanded leaves, whose tips become, at the same time, dry,
somewhat drooping, and brownish-green. Two or three of the
expanded leaves nearest this shoot show similar changes, and a
brown or reddish streak on each side of the midrib may also be
found on them. Later on the central shoot dies and the expanded
leaves gradually become more and more affected, until all are
withered. As this occurs the shoot itself rots at its base and may
fall over or be easily pulled out from the top of the cane. The
leaf sheaths belonging to the internal leaves show progressively
greater destructive changes as the centre of the apical bud is
approached, when exposed by stripping. These changes are
greatest at the insertion of the sheath on the stem node, and are
always more severe than the changes in the corresponding leaf
blades would suggest. The inner sheaths may be completely rotted,
those next outside show dark purplish areas extending upward
from the base and surrounded by red markings, while those farther
out have only red bands, or lines, continuous at the base but broken
into spots or blotches, suggestive of splashings from a paint brush,
higher up. The apical part of the stem is found, on stripping away
all the leaf sheaths, to have markings in continuation of those on
the sheaths, at first reddish-brown, then brown and collapsed.
These markings extend down from the node into the internode
below, and evidently originate in anterior changes in the leaf
sheaths.

On sectioning an affected shoot in the earliest stages, before any
external symptoms are visible, the innermost white leaves, just
above the apical point of the stem and wholly enclosed within the
bud, show a purple or brown discoloration on each side of the mid-
rib. Later on this discoloration reaches the stem through the nodes
on which the affected leaves are inserted, these being usually a
short distance behind the still intact growing point. The upper
affected internodes of the stem become soft at the same time
as the inner portion of the central leafy shoot rots, while four or
five of the next lower internodes show browning of the stem tissues
with here and there a red fibre, especially at the nodes. The outer
tissues of the stem, immediately below the nodes, are more deeply
discoloured than those farther in, corresponding with the brown
markings in the epidermis already mentioned. In the lower part
of the affected portion of the stem, only the nodes may be dis-
coloured. Sometimes even at this stage of the disease, the apex of
the stem completely rots away, leaving a cavity filled with moist
brown fragments of disintegrated tissue. This complete rotting of
the stem apex normally occurs, however, somewhat later in the
course of the attack, and forms a cavity bounded by the bases of
the leaf sheaths, and containing a strongly smelling mass of decayed
tissue. Longitudinal fissures may penetrate the softer tissues still
farther down. and at times nothing but the rind and bundles is left
in the internodes. The decay may progress down to the base of
the cane or be arrested at some point higher up. The discoloration
referred to above, both in the inner sheaths and in the tissues of
the stem, originates, according to the author, in the phloem of
the vascular bundles. There is no gum fiux in the affected
tissues.

583

Quite similar changes, allowing for the differences in size and
differentiation, may be found in the tiller-buds below soil level,
especially after ratooning. These may be rotted even when still
surrounded by a normal bud sheath.

At the same time that the main shoot is checked in growth by
the onset of top rot, the dormant buds at many of the nodes lower
down commence to sprout. In many cases these shoots develop
into canes. Sometimes the apical point of the main shoot escapes
damage until such time as the disease lower down is checked;
it then continues to grow and a normal cane may be produced
except for certain markings in the leaves or in a few nodes.
Unless the growing point becomes involved, recovery takes

lace.
if The attack develops irregularly in the cane stool, often affecting
only some of the shoots and these not necessarily in the order of
their development, though the primary shoots are most commonly
the first to be attacked.

The varieties most affected were Rappoe (Rose Bamboo), the
chief cane cultivated on the Herbert River, and Striped Singapore.
Meerah and white Bamboo (Louzier) were also susceptible. No
disease was seen in Lahaina, Violet, or Cheribon.

Top rot is usually most virulent in March in cane nine or ten
months old, but can attack much younger plants. There is no
evidence that it arises from the use of diseased cuttings for plant-
ing, and seed selection does not appear to be a satisfactory method
of control. Cuttings from diseased stools may produce healthy
plants, and in some cases diseased plant cane appears to have given
a healthy ratoon crop. There is some evidence of spread to adjacent
plants in the field, and also, though less satisfactory, of persistence
of the infection in the soil of certain areas. Soil conditions do
not greatly affect its incidence, though it was more common on
sandy soils; virgin soils are not immune, while rich manuring
appears to have favoured the disease. Low-lying areas were
most commonly affected in 1903. The author believes that a low
rainfall during the early part of the growing period of the crop
(May to October), followed by excessive rain in January, predisposes
to attack.

No organism to which the disease could be attributed was found
in the innermost sheaths of the apical bud—the first to show
symptoms of attack. Later on secondary organisms, fungi and
bacteria, attack the disorganized tissues and cause the foul-smelling
wet rot already mentioned. The author believes that the early
symptoms found at the tip of the shoot result from chemical changes
induced by a pathological condition of the roots of affected plants.
The lateral roots were found to be softened and decayed from the
tip back towards the main roots, and the latter were more or
less decayed in their turn. In the early stages of this decay the
normal white colour is replaced by a purple tinge. Cases were
seen in which the decay had been arrested and new healthy roots
had developed. This corresponded with recovery of the diseased
shoots.

The root decay is believed to be due to the attack of a parasitic
fungus, which is briefly described and figured, but not named. It

584

is suggested that it is possibly identical with an organism found
by Kamerling occasionally in the ‘ Wortelrot’ disease of sugar-cane
in Java. Various other organisms were found in the affected roots,
but no inoculation experiments with pure cultures appear to have
been carried out with any of them.

Treatment is not discussed, except for the suggestion that the
growing of resistant varieties may lead to control of the disease.
Karly planted cane is stated to escape injury from top rot in many
cases.

Corrt (J. H.). Wortelrot in EK 28 in Kediri. [Root rot in
EK 28 in Kediri.]|— Meded. Proefstut. Java Suikerind. 7,
pp. 291-307, 1928.

The results of recent experiments on the effect of different
periods of rotation on the control of root rot in the sugar-cane
variety EK:28 [see this Review, ii, p. 526] showed that this trouble
was more prevalent in biennial than in triennial crop rotation
(10-42 as against 3-42 per cent.) The extreme limit of the period
of non-occupation of the land by cane in biennial rotation is 173
months as compared with 294 months in triennial rotation. With
late maturing varieties, however, the period of non-occupation in
triennial rotation is only 18 months, this approximating closely to
the extreme limit in biennial rotation. The probability of root rot
is therefore greater in EK 28 when grown after late maturing
varieties, such as DI 52. Hence also the liability of EK 28, itself
a late ripening variety, to root rot when grown for many years in
succession on the same ground. In one experiment the percentage
of root rot in EK 28 immediately following the same variety was
7-17, as compared with 3-13 after other varieties.

Under Kediri conditions the incidence of root rot in EK 28 on
red laterite soils is very slight.

BranDEs (E. W.) & KiapHaak (P. J.). Cultivated and wild hosts
of Sugar-cane or Grass mosaic.—Journ. Agric. Res., xxiv, 3,
pp. 247-261, 4 pl., 1923.

The results of inoculation experiments, the technique of which is
described, carried out from 1919 to 1921 on over forty species of
cultivated and wild grasses proved the following thirteen to be
susceptible to the disease known as sugar-cane mosaic, but which
should be more properly termed grass mosaic: sugar-cane (Sac-
charwm officinarum), maize (Zea mays), sorghum (Holcus sorghwm),
pearl millet (Pennisetum glaucwm), eulalia (Miscanthus sinensis),
wild sugar-cane (Saccharum narenga), bull grass (Paspalum boscia-
num), erab grass (Syntherisma sanguinalis), yellow and giant foxtail
(Chaetochloa lutescens and C. magna), barn-yard grass (Lchinochloa
crusgalli), Panicum dichotomiflorum, and Brachiaria platyphylla.

The virus was artificially transmitted in one series of inoculations,
one half to two ces. of cell sap (obtained by squeezing young stalks
in a powerful press under mineral oil) being injected near the growing
point by Leur all-glass hypodermic syringes. In one instance
the virus was passed through a rather coarse Berkefeld filter, but
was still virulent in 75 per cent. of cases. In other experiments
the virus was shaken with various disinfectants before injection,

585

none of the inoculations being successful except on one plant in
a series of four in which the virus was treated with phenol.
Virulent virus, kept for 24 hours, was found to be unable to cause
the disease.

From these experiments it appears that the virus of grass mosaic
is less stable than that of other similar diseases, notably tobacco
mosaic. It loses much of its virulence during manipulation or
chemical treatment.

The ingects used in the insect transmission series of experiments
were Aphis maidis, Kolla similis, and Draeculacepha mollipes,
only the first of which was proved to act as a carrier of mosaic.

Certain varieties of sugar-cane belonging to the slender North
Indian type (which includes Uba, Kavangire, and others) formerly
regarded as immune, were found to be susceptible to mosaic, but
the disease attacked them in such a mild form as to be scarcely
noticeable.

In the course of the experiments a method of transferring aphids
from one plant to another was developed by which small bits of
infected leaves covered with aphids were clipped off and tied to
healthy plants. Controls (a) with similar infected portions with
the aphids removed and (b) with healthy leaves covered with non-
virulent aphids were necessary.

The result of tests in Southern Georgia for resistance to mosaic
of forty varieties of maize planted in close proximity to infected
Louisiana Purple sugar-cane plants showed that of the twenty-three
infected, the northern and western varieties were much less liable
to attack than the southern ones. This is believed to be due to the
subnormal development of the former, which frequently induces
resistance to experimental infection, rather than to any inherent
immunity. It was shown by data on the yield of seventeen
varieties of southern field maize that mosaic caused a reduction in
weight ranging from 0-4 to 50-6 per cent.

Field observations in Georgia indicate that natural infection of
sorghum (especially the Honey and Sugar Drip varieties), pearl
millet, crab grass, bull grass, giant foxtail, and Brachiaria is wide-
spread near affected cane in the sugar-cane belt.

The results of experiments to determine the possibility of seed
transmission of mosaic were negative. This supports the con-
clusions of various authorities in Java, who found that sugar-cane
seedlings from mosaic parents remain healthy unless infected from
external sources. It appears, therefore, that the virus is not trans-
missible by the seed.

RAGUNATHAN (C.). The occurrence of teleutospores in Hemileia
vastatrix B. & Br.— Trop. Agric., |x, 2, p. 128, 1923.

In order to obtain information on the occurrence of teleutospores
of Hemileia vastatrix in Ceylon, periodic observations of Coffea
arabica, C. robusta and C. liberica were made at Peradeniya between
May 1921 and April 1922. Teleutospores were found in every
month except August and October 1921 and April 1922, their
absence presumably being due to the development of new foliage
in August and April and to the heavy rains in October. No
definite statement can be made regarding the reasons for the

586

occurrence of the teleutospores except that it is dependent on
climatic conditions.

On Ist February 1922 a single teleutospore of Hemileia canthit
was observed on Canthium campanulatum. This had produced
a promycelium in the sorus. The teleutospore was much smaller,
and the promycelium more slender and brighter in colour, than in
H. vastatrix.

Iro (S.).. Uromyces of Japan.—Jouwr i. Coll. Agric., Hokkaido Imp.
Univ. (Sapporo, Japan) xi, 4, pp. 211-287, 3 pl., 1922. [Ree’d
1923].

The author gives a complete list of the species of Uromyces and
Pileolaria recognized in the Japanese flora, fifty-six of the former
genus, and three of the latter. Nineteen are endemics, twenty-
three occur also in America, and twenty-three in Europe. There
are eight new records for Japan, nine species, before recorded, are
excluded from the flora, six are now recognized as synonyms, and
three do not belong to these genera at all. The single new species
U. viciae-unijugae is allied to U. heimerlianus P. Magn., but is
distinguished by the thicker wall of both the uredo- and teleuto-
spores. The species are arranged according to the natural orders
of their host plants, and where required, a key is given for the
species occurring in each order. Under each species are given all
references to its literature, a full synonymy, localities with dates
and collectors’ names, and its world distribution. The work closes
with a list of the accepted fungi and a host index.

Mayor (E.). Etude expérimentale d’Urédinées hétéroiques. [Ex-
perimental investigation of heteroecious Uredineae. |— Bull. Soc.
Neuchétel. Sci. Nat., pp. 67-78, 1928.

The first part of this paper deals with Hyalospora polypodii-
dryopteridis (Moug. & Nestl.) P. Magnus, the uredo- and teleuto-spore
stages of which occur on Dryopteris linnaeana and D. robertiana
respectively. This fungus is very widely distributed throughout
Europe and has also been reported from the United States. Its
life-history, however, was hitherto incompletely known as the host
of the pyenidial and aecidial stages had not been discovered.

In June 1919, at Perreux [Sadne-et-Loire] the author observed
aecidia on the three-year-old needles of Abies pectinata seedlings
growing among ferns which in the previous year had been severely
infected by H. polypodii-dryopteridis. Subsequent observations
showed that the pyenidia of the fungus developed only on two-
year-old needles and the aecidia on three-year-old ones. In May
1920, teleutospores were collected on D. linnaeana growing near
the Abzes affected in 1919. Four seedlings of A. pectinata were
inoculated with these teleutospores the same day and developed
the typical symptoms of infection in April 1921, numerous pyenidia
being present on the needles. Repeated attempts to secure the
development of aecidia gave negative results.

In May 1922 aecidia were collected on Abies pectinata growing
on the site mentioned above and inoculated into very young fronds
of D. linnaeana and D. robertiana. Those of the latter withered
almost immediately, while D. linnaeana remained healthy until

587

June, when the first uredospores appeared. The teleutospores
developed in the spring of 1923. The fungus therefore requires
a minimum period of four years to complete its life-cycle. The
pyenidia and aecidia of H. polypodii-dryopteridis are very
inconspicuous, and infection never takes place on a large scale,
which accounts for these stages having been so long overlooked.

FLeROFF (B. K.). K quTonorun Ustilago avenae Pers. 10 1aHHHM
KYIbTypH in vitro. [Contribution to the cytology of Ustilago
avenae Pers. based on cultures in vitro].—Trans. Myc. & Phyto-
path. Sec. Russian Bot. Soc., 1, Trans. Moscow Branch, pp. 23-
36, 1 pl., 1923.

After a brief review of the work done by other investigators in
the study of the Ustilaginaceae, the author describes his culture
experiments im vitro by which he established the existence of two
races of Ustilago avenae differing from each other in the germina-
tion of their spores. Both races were collected on unnamed species
of cultivated oats, the first in the province of Vladimir, and the
second in the vicinity of Moscow.

In water and weak nutritive media the spores of both races
produced promycelia with typical clamp-connexions and a small
number of sporidia, which fused together (conjugated) and gave
rise to a mycelium, but in a more concentrated medium (gelatine 8
per cent., KH,PO, 0-05 per cent., MgSO, 0-02 per cent., glucose
5 per cent., Liebig’s extract 1 per cent.) the differences were clearly
apparent. The germinating spores of race 1 produced a large
number of conidia which were never seen to fuse together or to
give rise to mycelium ; in a few days the whole surface of the agar
was covered with comparatively large colonies of budding conidia.
On transferring such colonies into a liquid medium (the formula of
which is given) the fungus continued its budding. After 6 to 7
days the conidia began to increase in size, became rounded and
finally formed chlamydospores, which germinated on attaining
maturity. These chlamydospores differed from those produced in
nature by their thicker walls and by their larger size (some being
about twice as large). The mycelium of race 1, produced in a weak
nutritive medium as described above and then transferred to a more
concentrated one, immediately began to produce sporidia which
multiplied by budding and never fused together. Race 2, however.
on the same concentrated medium and under similar conditions,
produces conidia which after 4 to 5 days give rise to a mycelium.
The same occurs in a liquid medium, the growth of the mycelium
being like that ordinarily found in smuts. About a fortnight after
their development in the liquid medium, the unicellular hyphae
start to branch after developing transverse septa, while a few of
them begin to swell and to break up into separate cells, with
thickened, brown walls, which are finally transformed into spores,
The formation of spores is, however, considerably less abundant
than in race 1, and they much more resemble the natural spores
both by their size and the structure of their walls. In’germinating
these spores produce a promycelium with typical clamp-connexions.

With regard to the cytology of U. avenae the author determined
that the spores of this fungus obtained in vitro are formed from a

588

uninucleate cell without any preliminary nuclear fusion, and that the
mycelium on which the spores are borne is uninucleate throughout
all the stages of its development. On the other hand a binucleate
mycelium develops in those cases in which there is either a fusion
of two cells of the promycelium or of two conidia, and a similar
condition may arise at times by the simple division of the nucleus,
in a conidium developing into mycelium. The reduced type of
sexuality already known to exist in the smuts can thus, he points
out, be still further reduced in culture.

SmiTH (J. H.). On the apical growth of fungal hyphae.— An. of
Bot., xxxvil, 146, pp. 341-343, 1923.

An account is given of detailed observations regarding the
growth of fungal hyphae, the tests bemg undertaken by the author
in order to check the generally accepted statement in text-books
that the growth of hyphae is apical. The fungi tested were species
of Phytophthora, Aspergillus, Penicillium, Pyronema, Rhizoctonia,
Rhizopus, Botrytis, and Fusariwm. Spores, or fragments of
mycelium were sown on clear prune agar poured on cover-slips,
which were then inverted over Van Tieghem cells and the prepara-
tions incubated at 24° to 25°C. After germination, when the
hyphae had reached a convenient size, the lengths of the segments
already formed were measured, at varying intervals of time, over
a period of from five to fifty-six hours. Where septa were absent
or difticult to distinguish, the intervals between successive branches
were determined.

The experiments have demonstrated that growth takes place at
the tip and that no appreciable elongation occurs in any other part
of the hypha. In view of the wide range of genera tested, this
would appear to be the general rule for fungi and may be con-
trasted with the growth of filamentous bacteria, in which each of
the segments expands at the same rate, and of algae, in which both
apical and intercalary growth occurs.

Berit (M.). Enumération des champignons signalés au Congo Belge.
[List of fungi recorded in the Belgian Congo. ]—Bul/. Jard.
Bot. de l Etat (Bruaelles), viii, 1 pp. 67-101, 1923.

The mycological flora of the Belgian Congo is still very little
known. So far only 593 species have been recorded, distributed
among about 326 genera and 42 families. The author, in this paper,
after a short introduction, gives a list of all records of Belgian
Congo fungi, arranged according to their orders; the reference to
the work in which each species was first described and the reference
in Saccardo’s Sylloge are supplied in each case. The habitat is noted
in many instances, and those species represented in the Congo
Herbarium in Brussels are indicated.

Da Camara (EK. deS.). Minutissimum mycoflorae subsidium Sancti
Thomensis Insulae. I. Mycetes. [A small contribution to
the fungus flora of St. Thomas Island. I. Mycetes.]. Reprinted —
from Anais do Inst. de Agron., 3 pp., 2 pl., Coimbra, 1928.

Hight species of microfungi are recorded, of which two are new,
namely, Culospora theobromae, in the cortex of Theobroma cacao,

589

which differs principally from C. bahiensis Speg., in its smaller
ascospores (35 to 45 by 7-5 to 10,4) and in its asci always con-
taining 8 spores, and Macrophoma nicotianae found on the stems of
Nicotiana tabacum.

CouTinuo (A. X. P.). Florae mycologicae Insulae St. Thomae
(Sinu Guineensi) contributio. {Contribution to the mycological
flora of the Island of St. Thomas (Gulf of Guinea).] Reprinted
from Anais do Inst. de Agron., 26 pp., 3 pl., Coimbra, 1922.

This paper gives a list of 76 fungi (of which 74 are Basidio-
mycetes) collected by the author in the island of St. Thomas during
1920 while he was engaged in pathological work. References to
the literature, the hosts, localities, and a short Latin description
are appended to each species. The author describes and figures ten
new species, of which three are wood-inhabiting Polypores.

The following Polyporaceae are recorded: on Theobromu cacao;
Poria ferruginosa, Homes pectinatus, Polyporus zonalis, Tranetes
gibbosa, T. sprucei, ? 7. sepium (Rav.) Berk., and 7. sanguineum :
on Cocos nucifera; Fomes ochrolaccatus, F. multiplicatus, F.
applanatus, Polystictus occidentalis, P. sanguineus, and Trametes
ohiensis: and on Elaeis guineensis; Fomes applanatus and F.
Seren.

Fruit and Vegetable Quarantine, Notice of Quarantine No. 56,
with Regulations.— U.S. Dept. of Agric. Fed. Hort. Board,
August 1923,

Under this quarantine order, coming into etfect on 1st November
1923, and framed with the purpose of preventing the introduction
into the United States of certain injurious insects, including fruit
and melon flies (7’rypetidue), the importation into the United
States is forbidden of fresh fruits and vegetables (i.e. the edible,
more or less succulent, portions of food plants in the raw or un-
processed state, such as bananas, oranges, grapefruit, pineapples,
tomatoes, peppers, lettuce, &e.) from abroad and of plants or
portions of plants (i.e. leaves, twigs, or other portions of plants, or
plant litter or rubbish as distinguished from clean fruits and
vegetables or other commercial articles) used as packing materials
in connexion with shipments of such fruits and vegetables, the
whole subject to the exceptions mentioned below. All special
quarantines and other orders hitherto in force restricting the entry
of fruits and vegetables remain in full effect, with the exception of
Quarantine No. 49 with regulations, on account of the citrus black
fly, which is superseded by this Quarantine.

The following is a compendium of the most important regulations
appended to the order:

All importation of fruit and vegetables must be free from plants
or portions of plants, as defined above. Dried, cured, or processed
fruits and vegetables, including dried products, cured figs, dates,
and raisins, &c., nuts, and dry beans, peas, &e., may be imported
without permit or other compliance with these regulations. Subject
to the restrictions now in force or which may hereafter be pro-
mulgated as to certain countries and districts, the following fruits
may be imported from all countries under permit and on compliance

590

with these regulations: bananas, pineapples, lemons, sour limes,
and grapes of the European or Vinifera type. Subject to the same
restrictions, any vegetables may be imported from any country
under permit and on compliance with these regulations, at such
ports as shall be authorized in the permits, on presentation of
evidence satisfactory to the United States Department of Agri-
culture that such vegetables are’ free from infestation with
dangerous insects, including fruit flies (Trypetidae), and that their
importation will not be the means of bringing such pests to the
United States.

In addition, the following exceptions are authorized for the
countries concerned :

Commonwealth of Australia—States of Victoria, South Australia,
and Tasmania. Upon compliance with these regulations and under
such additional conditions and safeguards as may be prescribed in
the permits, all fruits and vegetables from these three States will
be permitted entry at Seattle, Wash., and Portland, Oreg., and at
such other ports as may be specified in the permits.

Japan: Upon compliance with the regulations under Quarantine
No. 28, oranges of the mandarin class, including satsuma and
tangerine varieties, may be imported from Japan through the port
of Seattle and such other northern ports as may be certified in the
permits.

Mexico and Central America: Avocados or alligator pears may
be imported from Mexico and Central America upon compliance
with the restrictions of the order of 27th February 1914. Irish
potatoes may be imported from Mexico upon compliance with the
regulations of the order of 22nd December 1913.

Chile and Argentina: Upon compliance with these regulations
fruits and vegetables, other than those already exempted in the
first paragraph of the compendium above, may be imported from
Chile and Argentina under such conditions and through such
northern ports as designated in the permits.

West Indies: Upon compliance with these regulations all citrus
fruits from the West Indies may be permitted entry at New York
and at such other ports as designated in the permits.

Jamaica: Entry of pineapples from Jamaica is restricted to the
port of New York or such other northern ports as specified in the
permits.

Canada: Fruits and vegetables grown in the Dominion of
Canada may be imported from Canada free of any restrictions
under these regulations.

Application for permits to import fruits or vegetables authorized
in these regulations is to be made to the Federal Horticultural
Board in advance of the proposed shipments, stating the country or
locality of origin of the produce, the port of first arrival, and the
name and address of the importer in the United States to whom
the permit should be sent. If through no fault of the importer
a shipment should arrive before the permit is received, the goods
will be held in customs custody at the port of first arrival, at the
risk and expense of the importer, for a period not exceeding 20
days. A separate permit must be obtained for shipments from
each country and for each port of first arrival in the United States.

591

The permits of importation are issued m quadruplicate, one copy
of which is supplied to the applicant for presentation to the customs
officer at the port of first arrival.

All importations of fruits or vegetables are subject as a con-
dition of entry, to such inspection or disinfection, or both, at the
port of the first arrival as shall be required by the inspector of
the Department of Agriculture and shall be subject to re-inspection
at destination, at the option of that Department. Should any
shipment be found so infected with fruit flies or other dangerous
pests that in the judgment of the inspector of the Department of
Agriculture it cannot be cleaned by disinfection or treatment, or to
contain leaves, twigs, or other portions of plants as packing or
otherwise, the whole shipment may be refused entry. All charges
for storage, cartage, and labour incident to inspection and disin-
fection other than the services of the inspector, shall be paid by
the importer.

Wart Disease of Potatoes Order of 1923.—Journ. Min. Agric.,
Xxx, 4, pp. 363-366, 1923.

The main features of the Wart Disease of Potatoes Order of
1923, which revokes all previously existing Orders on the subject,
may be summarized as follows. ‘The appearance of the disease on
any land in England and Wales must immediately be reported to
the Ministry of Agriculture. Potatoes visibly affected with wart
disease [Synchytrium endobioticum]| must not be offered for sale.
The only potatoes allowed to be planted on land known to have
been infected at any time by wart disease are those stocks of
approved immune varieties which have been inspected while
growing and officially certified as true to type.

The following areas are declared by the Order to be infected.
The whole of Wales, the counties of Monmouth, Cheshire, and
Staffordshire, the county of Lancashire south of the Ribble,
together with Preston and Fulwood, North Salop, Birmingham,
and Sutton Coldfield, and certain parishes in the counties of
Worcester and Derby. No potatoes grown in an infected area
may be removed or consigned to any place in England and Wales
which is not in an infected area. This does not apply to ‘ware’
potatoes of approved immune varieties. All potatoes planted or
sold for planting must be officially certified either as having been
grown on land free from wart disease, or as having been inspected
and found to be free from the disease, or as being of an approved
immune variety true to type. When potatoes are sold for planting
the seller must furnish the buyer with the number of the relative
certificate. Potatoes grown outside Great Britain and Ireland
must not be sold for planting in England and Wales except under
a licence from the Ministry. The arrangements in connexion with
the issue of certificates are explained (a charge of 2s. 6d. per acre
being made when an inspection is required), and the restrictions
governing the sale of Scotch and Irish ‘ ware’ potatoes enumerated.

An Act to regulate the sale of Insecticides, Fungicides, Vermin
Destroyers, and Weed Destroyers; and for other purposes.
Queensland, 20th August, 1923.

Under the present Act any person in Queensland manufacturing

592

or dealing in insecticides, fungicides, vermin or weed destroyers
(called in brief in the Act ‘ Pest destroyers’) must, within 30 days
of the passing of this Act or of setting up in such trade, whichever
is the later date, and thereafter in each following year on or before
the 3lst January, give notice in writing in the prescribed form to
the Under Secretary of the Department of Agriculture and Stock
in Brisbane, of his name and place of business, the distinctive name
of every pest destroyer he then sells or proposes to sell during the
current year, and the places where the same can be purchased from
him. Additional notice is also required to be given of each new
pest destroyer or of any alteration in the constituents of those
already registered, before commencing to deal in such new or
altered pest destroyers.

Every notice is to be accompanied by: the fees prescribed (5s.
for each pest destroyer to be registered and 2s. 6d. for each of those
already registered for the current year, the constituents of which are
altered as above); a fair average sample for analysis of each pest
destroyer mentioned; a statutory declaration by the dealer stating —
the distinctive name of each pest destroyer, that each sample is
a fair average sample of the pest destroyer it represents and is not
substantially different from the pest destroyer which the dealer will
supply throughout the year under its distinctive name, the con-
stituents of each pest destroyer, the constituents thereof which
are claimed to be active constituents, the percentage in which each
constituent is contained therein and what percentage of each con-
stituent is contained in that part of the pest destroyer which is
soluble in cold water, the net weight which shall be contained in
each respective package when sold; a specimen copy of the invoice
relating to each such pest destroyer; and a specimen copy of the
prescribed label to be affixed to each package. Each such label is
to show: the distinctive name of the pest destroyer; the net
weight contained in the package; a statement of the active con-
stituents; all directions, if any, for the use of the pest destroyer;
the name and address of the wholesale dealer; and such other
matters as may be prescribed.

A label as prescribed above is to be affixed, on or before delivery
to the buyer, on each package of pest destroyer. Every dealer
who sells any pest destroyer of a greater value than 5s. must
also sign and give to the buyer an invoice showing: the name
and address of the dealer; the net weight of the pest destroyer
supplied, with the name thereof; a warranty, the wording of which
is given, that the constituents of the pest destroyer so sold, and the
percentage in which each constituent is contained therein and in
that part thereof which is soluble in cold water, accurately
correspond with the constituents and percentages stated in the
statutory declaration supplied as above. Every buyer shall be.
entitled, on complying with the regulations, to submit a sample of
a pest destroyer bought by him to an official analyst for analysis,
and to receive a certificate of the results of such analysis.

Other sections of the Act deal with the appointment and duties
of inspectors, penalties, and other details regarding the administra-
tion of the Act.

INDEX OF
PAGES
Adams, J. F.. 376
Agati, J. A. 279
Allen, R. F. : 401
Allyn, O. M. : 446
Anderson, H. Ww. . 270
Anderson, P.J. . 251, 460
Appel, 0. : : 509
Armstead, D.. 544
Armstrong, S. F. 57
Arnaud,G. . . 493
Artschwager, E. F. 569
Ashby, S. F. 4 183
Atanasoff, D.. 285
Atwood, W. M. 266
Ausborn 550
Bacon, C. W. . 421
Badoux, H. 246
Bailey, LW. 515
Bailly, P. 11
Ballard, E. . 367
Ballard, W. S. 268
Ballings, M. 370
Bally, W - 368
Barrett, J.T. . 406
BarssjH, P.- . = i200
Bartholomew, E. T. 87, 406
Bartlett, H. H. : Sede
Bausch, H. 551
Beach, W.S. . 433
Beauverie, J. . 361
Beeli, M. : . 588
Bennett, C. W. 82, 371
Bennett, J. P. 87
Benoist, J. Pe gh! ath as eT
Bertus, L.S. . : : : . 527
Bevan, W. . 2 : . 394
Bewley, W. F. 148, 250, 346, aps
Biers, FM. .
Binz, A.. ; sei
Bioletti, F. T. . . 438
Birmingham, W. A. . 299
Bisby, G. R. : 386, 423
Blaringhem, L. . 3862
Blin, H.. 2 eo
Blumer, S. . 180
Bonanni, A. . 415
Bonar, L. 50, 76
Borg, J . 452
Borg, P. . ; , z . . 585
Botjes,J.O. . é s - 519, 571
Bouillard, R. . : , on] Oe
Bourne, B. A. 467
Bowman, J. J. 407
Boyce, J.S. . 482
Boyle, L. W. . . 458
Brandes, E.W. . 217, 381, 584
Branstetter, B. B. . . 218
Bredemann, G. 162
Brentzel, W. E 313

VOL. IL.

AUTHORS

PAGES
Brereton, W. Le G. 437
Briggs, W. R. . 364
Briton-Jones, H. R. 113, 449
Brittlebank, C.C. aoe
Britton, W.E. 219
Brothuhn, G.. : . 224
Brown, J. G 49, 153, 217
Brown, N. A. 355, 370
Brown, W.. 24, 328
Bruner,S.C. . 258, 524
Bryce, G. 370, 374
Bubak, F. 4 . 142
Buchheim, A. . d4l1
Bunting, R. H. 495, 497
Biiren, G. v. . . 242
Burger, 0. F. . 309, 364
Burr, S. . 567
Butler, E. J. . 379
Butler, O 18, 507
Caballero, A 191
Cadoret, A. . 119
Campanile, G. 310
Carleton, M. A. 321
Champion, H. G. 41
Chan, T. A. B. 463
Chardon, C. E. 390
Chavastelon 530
Chevalier, A. . 225
Ciferri, R. 91, 166, 167
Claus, E. - ; : 422
Clayton, E. E. - = ‘ 428, 477
Clinton, G. P. = - Sey
Coert, J. H. 584
Colby, A. S. 218
Coleman, L. C. 380
Cook, F. C. 522
Cook, M. T. 109, 377
Coons, G. H. 73, 204, 513
Corley, G. L. 500
Cortini- Comanducci, LF dppcenealy
Cotton, A. D.. P 207, 385
Coutinho, A. va RP: . 589
Crawford, R. F. 92
Crépin, C. 27, 101, 334
Csete, A. oe

Cunningham, G. H.
68, 121, 165, 275, 319, 320, 373

Curtis, K. M. 122, 504
Da Camara, E. de S. 588
Dade, H.A. . 210
D’Angremond, A. . 36
Darnell-Smith, G. P. 3538
Dash,J.S. . 33
Davies, DEV. 401
Davison, F. R. 81
Day, L. H.. 546
De Busk, E. F. 364
De Koning, M. 430

594

PAGES
De Long, W. A. . ° . Ota
Demaree, J. B. ‘ : . 283
De Monicault, P. . : : ay Le
De Wildeman, E. . ; . 350
Dickson, B, T. A 26, 547 ©
Dickson, J. G. : : 536,
Dietz,S.M. . - : 209
Diffloth, P. “ . . 582
Doidge, E. M.. 141, 352, 386
Doolittle, S. P. 512, 514
Doran, W. L. . 281, 516
Dorst, eC 5 : 572
Drechsler, Cx és - ‘ 5
Dreger, C. : : 538
Duboys 5 : : . 288
Dacelaw. : : ; Q 2 160
Ducomet, V. . 5 feu
Dufrénoy, J. 49, 95, 185, 431, 512, 560
Duggar, B. M. ; . 133

Durrell, L. W. : . 213
Dutton, W. C. c : - fake

iBarlewk sens . 525
Eastham, J. W. 395, 532
Eaton, B. J. . - - . 396
Eddy, E. D.~ . ‘ : : : 5
Edson, H. A. . é : - op Stet)
Edwardes, J. . : : . . 427
Elliott, J. A. . . ; 92, 215
Elmer, O. H. . - & : zn el
Eriksson, J. . é : 2 5
Esdorn, I. : : ° - . 557
Essig, F. M. . ‘. : : eA:
Faes, H. . ; C : 43, 45
Farley, A.J. . = : : . 506
Fawcett, G. L. . 62, 338
Fawcett, H.S. 66, 406, 539, 542
Fellows, H. . c 5 = BY
Ferdinandsen, C. . : 198, 218, 563
Firor, 3. We. . ; : : 3) Ekoo
Fisher, D. F. . - “ 5 . 455
Fitch, M. W. . : 506
Fleroff, B. K. . 587
Foéx, E. . : - 173, 334
Folsom, D. . : . ; toi A
Fracker, S. B.. : . 345
Franchini, G. 176, 77, 228, 230, 424, 523
Fraser, W. 12 : : . 459
Freeman, W.G. ; - . 3894
Friederichs, K. ; : : . 368
Fromme, F. D. : - 244, 346
Fulton, H. R.. : : : ei 2S
Funke, G. L. . . : . 23, 330
Gadd, C. H. ‘ : . 543
Gandrup, J. . : : ‘ . 3823
Garbowski, L.. : s : 2269
Gard, M.. : : . 187, 347, 528
Gardner, M. W. 40, 455, 485
Garner, W, W. 80, 421
Gassner, G. . 554, 557
Giumann, E. . 87, 145, 341
Gehring, A. A, : 224, 510
Gibson, F. - : é . 249
Girola, C. D. . : : - appl ley
Glasson, A. K. 2 : ; . 390
Gleisberg, W.. 351, 432

todfrey, G. H. : ; . 435

Harter, L. L.

INDEX OF AUTHORS

PAGES
Godkin, J. 357
Gomme, W. . 3809
Goss, R. W. . 386, 521
Gossard, H. A. : . 452
Gram, E. 289, 421, 487
Graulund, R. . C : . 457
Greenbaum, S. Sh | . 410
Greenwood, F. W.. 432
Griffee, F. - 210
' Griffiths, M. A. 458
Groh, H. : 3 : 3 . 886
Grove, W. B.. 5 : : = Ted
Hahn,G.G. , : - - : 3
Halls Ras s 3 - Breit
Hamblin, C. O. : 5 F . 437
Hammond, A. A. . : : 276
Hara, Ke. ; 2 3 238
. Harland, S. C. 544
Harrison, T. H. 120

418, 419, 464, 486, 564, 565

Hasendhrl, R. 284
Hawkins, a AL es $ : . 268
Haywood, JK : : . 168
Heald; ED. : - . 264, 458
Hecke, L. > 3 . 114, 400
Hedgecock, G. ren - 5 5 3, 348
(Hemmiy T . 5 . ss wlG
Heng], F. : : : - 582
Henning, E. : ° : 5 19
Herbert, D. iN é - > . 164
Higgins, iB. B: : 5 ° Sie
Higham, J. F. . 386
| Hiltner, E. 403
' Hiltner, L. 503
| Hind) ROR... é 2 : 468
Hintikka, Td: “, - = . 349
Hockey, J. F. : é 2 sisted
Hopkins, E. F. 24, 308, 414
Horne, T. ‘ 4 : 2 ey ipo
Horton, E. . : : . 168
- Héstermann, G. 220, 222, 223, 457
Hotson, J. W. : : . 483
Howard, A. . 307
. Howard, G. L C. x 3 - 3807
Howard, N. O. : - ‘ . 185
Howitt, J. E. . 4 : - . 436
Hubert, E. E. : E : . 90
Humphrey, C.J. . : * . 481
Hungerford, C. W. 13, 86, 100
Hunt, N. ke - : ; a 3, 348
Hurd, A.M. . : . . . 361
Hursh, iC: -R: * : : aierils:
Ito, S. 586

Jackson, H. S. . : 3 4 aT

Janchen, E. - : : . 422
_Janini Janini,R. . : : - 405
Janson, A. . : - 3 Aaa WG!
Jardine, J. T.. 206

Jardine, N. Ki. f ; t : 478.

. Jarvis, E. : . = AO
Jarvis, H. = : - 3 cae &)°)
Jegen, G. : = 3 . 802

' Jennison, ef M. : : : . 8d
Jewson, S. T.. : x ~ 825

Jochems, S. C.
Johnson, J. .
Johnston, S.
Johnston, T. H.

Jolkevitch, A. I.

Jones, L. R.
Jones, 8. G.
Jgrstad, I.
Junge, E.

Kasai, M.
Kauffman, C. H.
Keissler, K.
Kelly, W. W. .
Kelsall, A...
Kendrick, J. B.

Kentish Wright, O. ;

Kerber, H. M.
Killian, C.
King, C. J.
Kinney, E. J..
Klaphaak, P. J.
Kock, G.. -
Kofoid, C. A. .
Kohler, E.
Konig.
Kopke, E. Ww.
Kotila, J. E.

Kreuzpointer, J.

Kulkarni, G. S.
Kuyper, J

Lacey, M.S. .
Lachaine, O. W.
Lafferty, H. A.
Lagerberg, T. .
Laidlaw, W.
Lambourne, L.
Lang, F.
Langeron, M..
Lauritzen, J. I.
Ledeboer, F.

Lee, H. A. 62, 68, 88, 89, 108, 141, 469

Lehman, S. G.
Le Moult, L.
Leonian, am isle
Levin, L..
Levine, M. .
Levine, M.N..
Levy, E. B.
Semeg 7.
Line, J

Link, G. K. K.
Lipscomb, G. F.
Long, A. W.
Ludwigs, K.

Lundegardh, H.

Liistner, G.
Lutman, B. F.
Lyneh, W. D.

Maas, J.G.J.A. .
MacCallum, B.D. .

MacInnes, J. .
Maffei, L .
Magness, J. R.
Mahner, A.

Mains, E.B .
Malaquin, A .

396, 498, 494

131, 457, 499

PAGES
314, 346

566

66, 136, 137
195

201

223

281
189
342
225

. 549

40, 485

. 284
189

74, 584

12, 308

99, 119, 347
. 116, 181

498, 494

472 |
484 |

INDEX OF AUTHORS

Manaresi, A. .
Maneval, W. E.
Mangin,L. .
Manny Hei.
Manns, T. F. .
Martin, G. H.
Mason, F. A. .
Massey, L. M.
Matsumoto, T.
Maublane, A.
Mayor, E.

McCormick, F. IN ;

McDonald, a

McDonnell, C. C.

McGinty, R. A.
McKay, M.B..

McKinney, H. H. :

McLean, F. T.
McLuckie, J. .

McMurtrey, J. E.

McRae, W

McWhorter, F. Ps 4

Medalla, M. G.
Meier, F.C. .
Meinecke, E. P.
Melchers, L. E.
ae 1G JOKE.
Melin, E
Miége, E.
Milbrath, D. G.
Miles, A.C...
Millard, W. A.
Miyake, C.
Mizusawa, Y..
Mole, D. C.
Molz, ries
Montemartini, an
Moreau, L.
Morettini, A. .
Morquer, R. .
Morris, H. E..
Morrison, F. B.
Morstatt, H.
Moss, E. G.
Moss, E.H. .
Miller, H. C..
Miiller, K.
Miiller, Kz /On

Miiller-T hurgau, H.

Munerati, O.
Munro, D. G.

Nadson, G. A

Nagpurkar, 8. D.

Nakada, N
Nakajima, T. .
Nakata, K.
Nannizzi, A. .

Narasimhan, M. =F ;

Neal, D. C.
Nelson, R.

| Newhall, A. G.

Newton, M.
Newton, R. G.
Nicholls, H, M.
Nicolaisen
Nishimura, M.
Nisikado, Y.
Noack, M.

88, 89

2 BRE
125, 151, 301
Stace O88
519, 567
230, 416

427

Oo hat BTe
. 170, 416

. 197

437

322

. 300

. 221

. - 257

417, 562

80, 421

96

170, 416, 550
416

470, 471

ao, 299, 302

262
448

566

+. 888
. 413
. 524
502, 524
. 294
22, 563
. 441
77, 227
. 482
357
519
304
529
315
230
457

596 INDEX OF
PAGES
Nobécourt, P.. - 81, 446

Noble, R. J. . : . 398
Nordmann : : : : . 120
Norris, D. : : : : . 9367
North, D.S. . ; 3 2 . 578
Nowell, W. . : : ; 110
Oberstein : 5 ‘ - . 224
O'Byrne, F. M. R ; 3 - 363
Orton, W. A. . - ; : . 280
Osborn, T.G.B. . . . 152, 291, 292
Osmun, A, V.. 440, 460

Osterwalder, A

269, 278, 275, 277, 278, 302
Paine, S.G. . . : one OO 47
Palm, B. T. ; : 35, 346
Pape, H.. = ; 2 . . 449
Paravicini, E.. : - : . 422
Parker, J. H.. ‘ . : 5) alle
Parker, T. : é : ‘ . 375
Partridge, G. . - : 2 . 465

Patouillard, N, r ; JAMO

Paxton, G. E., 61
Peltier, G. L. . : : : Se
Perotti, R. s : . : . 327
Perret, C. - 568
Petch, T. 7, 294, 473, 576
Peters ae . 484
Pethybridge, G. H. 2 AGS
Peyronel, B. . : : 5 onelit:
Phillips, E. H. . : : 130
Pichler, F.. . 324

Pierce, L. - ; : - pL,

Plunkett, O. A. 2 E ; . 534
Pole Evans, I.B. . : by RLS
Pole Evans, M. E 83
Pommer, E. . 510
Poole, R. F. : 30, 91, 102
Pope; WwW. LT. . A =) ie .- 321
Priestley, J. H.. . ; . 331, 384
Pritchard, F J. . 5 < 51540
Prowse, V. McN. . ; 395
Putterill, V. A. . 126, 271, 451
Quaintance, A. L. 168
Rabbas . = : ; “ snt2zs
Raeder, J. M. . ‘ : : 5 oe
Ragunathan, C, : : - 585
Rahman Khan, A.. 307

Rambousek, F. + : 466

Ramsbottom, J. . - : . 134
Ramsey, G. B. - i “ . 296
Rands, R. D. . a i 246
Rankin, W. H. 17
Rao, K.A. . 418
Rast, L. E. . ; 66
Ratcliffe, G. T. : 441
Rathbun, A. E. 4 5
Rayner, M. C. : 326
Reckendorfer, F. : “ - 533
Reddy, C.S. . : : . 313, 357
Remy, T.. 510
Rhynehart, J. ‘G. 5. LA
Richards, B. L. ; - 85, 89
Richardson, A. D. . ; - . 430
Richter . - - ; : . 575
Riehm, E.. . : : . 169, 552

AUTHORS

PAGES

Ringoet . ° . : - 577
Ritzema Bos, J. ; 504, 544
Rivier, A. ‘ * <i LOZ
Roberts, J. w. = 5 - nly
Roldan, E. F.. 5 - . 261
Rosa,gaTa) . “ - 466, 573
Rosen, H.R. . . 158, 447, 497
Rostrup, S. . 3 : . . 487
Ruban, G. 5 : : - - 463
: Russell, H. L. = * ‘ serena
Ruth. .WiaeAe : . - 225, 323
Ryan, R. W. . é : - - 534
i GaN c . 529
Salmon, E. os 132, 168, 308, 381
Sampson, K, . . 400, 401
Samuel,G.. - 152, 291, 298, 309
Sanderson, A.R. . Bie Wife:

Sandsten, E. P. : 5 2 :
Savastano, L. . . 5 . 408, 404
Schaffnit, E.
Solider

Schellenberg, H. C. : : . 483
Schikora, F. . . - . 410
Schilling, Ee : : 2 als
Schlumberger, O. : 175
Schmitz, H. 51, 187
Schribaux : : : A 3) BIS
Schultz, E.S.. : 5 387
Schwarz, M. B. : - 92
Scott, C.E. . : - 190
Scott, I. T. 347
Seaver, F. J. . . ; 562
Selby, A.D. . . - - - 505
Severin, H. H. P. . . ¢ . 516
Shapovaloy, M. 29, 387, 389

Sharples, A. . 232, 291, 337, 425, 426

Shaw, F. J. F.. : - ati fen
Shear, C.L. . : : 226
Sidenius, E. . 5 5 - 295
Siggers, P. V.. : 5 : 34
Simmonds, H. W. . ; “ » 215
Simmonds, P.M 2 - ; . 459
Skubez, V. 2 16
Small, W. d 156, 163, 263, ee
Smith, C.0. . . é -

Smith, E. F. . : : : ‘10, =
Smith, E. H. . : F : 130
Smith, J.H. . : é : - 588
Smith, K.M.. - : 134
Smith, L.J. . - - é . 264
Smith, T.0. . : : . Ap te:
Snell, K.. : ; é 3 169
Snell, W.H. . 2 2 . 146
Snow, L. M. 5 - 163
Soursac, L. . : : . 193
South, F. W. . : - : . 238
Spaulding, P.. : : : «1 Sst
Speare, A. T.. . ; 311
Spieckermann, A. : 517
Spierenburg, D. . - : : 1
Spinosa, J. P.. - - 64
Staehelin, M . = : é 43, 45
Staiger, R. 4 < : «} ie
Stakman, E.C.. . 158, 499
Stanford, H. R. a, ead
Stell, F. . 335, 486

Steup, T. ; - - :
Stevens, F, iy. 5 : ~ | SO Se

INDEX OF AUTHORS

Stevens, H. P. . 3 . 139, 578

Stewart, F. C.. - r : -
Stiegler, A. . ° , 3 A
Stoddard, E.M. . . : .
Stone, R. E. . - = :
Stutzer, A. -
Sundararaman, S..
Surcouf, J. M. R.
Sutcliffe, H.
Swezy, O. 3 :
Swingle, D. B. 125, 221,
Tabor, R. J.

Takimoto, K, .

Takimoto. S. .

Tanaka, T.

Tattersfield, F, - -
Taylor, J. W.. - .
Taylor, W. A.. - “ P
Taylor, W. H.. : : E
Tellez. O. 2 :
Tempany, H. A.

Thatcher, R. W.

Thomas, P. H.

Thomas, R. C.

Thompson, N. F.

Tisdale, W. B.

Tisdale, W. H.

Tits, D: °

ee nie, C. M.

' Tonduz, P. -

Tower, W. V..

Traverso, G. B.

Trinchieri, G..

Trost, J. F. : : ;
Trotter, A. . : A F
Troup, R.S. . - : °
Truesdell, W. H. .

Tryon, H. ; :

Tunstall, A. C.

413,

430,

67,
384,

Uphof, J. C. T.

Valckenier-Suringar, J. .
Valleau, W. D. = :
Van der Bij], P. A.

Bree Ney TB. hb) Haun tail

Van Hall, C. J.J. .
Van Harreveld, P..
Van Luyk, A..
Van Poeteren, N.
Vasters, J.

Veve, R. A.
Villedieu

79, 139, 249,

502, !

PAGES
Villedieu, G. . ‘ - A . 374
Vincens, F. : - 95
Vinet, E. 437
Vivet, E. - “ ° 104
Voglino, R. . - e ee > ae
Voukassovitch, P. . 312
Vriend,J. . . 35
Waite, M. B. . 168
Wakefield, F. W. . 391
Waksman, S. A. 85, 233
Walker, J. C.. 104
Walker, M. N. 512
Walton, R. C. 452
Ware, W. A. . 450
Waterhouse, W. Hs < . 807
Waters, R. 123, 273, 316
Weber, A. = - : - . 245
Weber, G. F. . A . 159, 211, 356
Weimer, J. L.
418, 419, 464, 486, 564, 565
Weir, J.R. . . 484, 531
Weiss, C. 0. . : . - 278
Weldon, G. P. . 374
Welles, GC. G.. 89, 141, 261, 444
Welsford, E. J, 355
Weniger, W. . 498

Weston, W.H. . : . L
Whetzel, H. HH. . 3 . 3805, 386
Whitehead, T. ° : :

Wieler, A . ° :
Wilbrink, G. . - - . 236, 468

Wilcox, R. B.. é : 128
Willaman, J.J. . . : ool
Willey, F. 209
Wilson, M. . 50
Wiltshire, S. P. 318

Wingard, S.A. . .- . 194; 244

Winkler, H. “ . : . 166
Winston, J. R. F : - 364, 407
Wober As? 7. : : : . 824
Woffenden, L. M. . 5 . . 384
Wolf, F. A. Aa 157, 478
Wormald, H.. 132, 308, 547
Young, H. C.. . . 82, 460
Woung, PAs i . ° 534
Zade, A.. 3 d 3 : . 214
Zappe, M.P. . s . uo « (219
Zeller, S. M. . 3 . = E heal
Zellner, J. : i R “ - 284
Zimmermann, H, . ‘. 58
Zundel, G. L. . 458

GENERAL INDEX

Abaca, see Musa textilis.

Abies grandis, Echinodontium tinctorium,
Fomes annosus, and F. pinicola on, in
U.S.A., 5381.

— pectinata, Hyalopsora polypodii-dryopte-
ridis on, in France, 586.

— —, Peridermium elatinum on, in Britain,
430.

— spp., Peridermium elatinum on, 431.
(See also Fir),

Acacia, Armillaria fuscipes on, in Ceylon,
295.

—, Cercosporella theae on, in Ceylon, 294.

—., Fomes applanatus on, in Ceylon, 295.

—, — rimosus on, in S. Africa, 142.

—, Irpex destruens on, in Ceylor, 295.

— mollissima, Polyporus lucidus on, in S,
Africa, 142.

— —, Trametes obstinatus on, in S. Africa,
142.

Acer, Rhytisma acerinum on, in U.S.A.,
481.

—, Torula ligniperdain wood of, in U.S.A.,
34.

— pseudoplatanus, see Sycamore.

— saccharinum, Cytospora chrysosperma on,
in Canada, 96.

Achorion gallinae, physiology and toxic
action of, 410.

— quinckeanum, physiology and toxic
action of, 410.

— schoenleinii, physiology and toxic action
of, 410.

Acokanthera veneta, infection of cats with
amoebae from latex of, 230.

Acrostalagmus, growth of, in calcium ni-
trate solution, 553.
— glaucus and <A. sacchari on rotted
sugar-cane setts in Argentina, 339.
Acrothecium on bulrush millet and maize
in India, 259.

Actinomyces on beet in Norway, 203.

— bovis, physiology of, 410.

— chromogenus, see A. scabies.

— scabies on beet in Czecho-Slovakia, 466.

——, on potato, control by green manur-
ing in Britain, 208, 519; by sulphur
in British Columbia, 519; in Nova
Scotia, 572; in U.S.A., 109; effect of
hydrogen-ion concentration on, 85,
520; manuring experiments against,
519 ; occurrence in Bermuda, 306; in
Britain, 138, 208, 519; in British
Columbia, 519; in Canada, 26, 465;
in Dutch E. Indies, 8, 423; in Ne-
braska, 386; in N. S. Wales, 354; re-
lation of soil temperature to, 137,
520; ‘solbar’ against, 132; toxicity
of sulphur to, 460,

Adelia acuminata, infection of, by Pseudo-
monas savastanoi, 12.

Accidium cinnamomi on Cinnamomum iners,
in Java, 297.

Aegerita webberi parasitic on white fly in
Florida, 369.

Aeginetia indice on sugar-cane in the
Philippines, 109.

Agaricus citri on citrus in Spain, 405.

Agave cantula, Colletotrichum agaves on, in
the Philippines, 108.

— zapupe, Colletotrichum agaves on, in the
Philippines, 108.

Aglaospora aculeata on tea in Ceylon, 294.

Agropyron, Puccinia glumarum on, in
California, 392.

— repens, Bacterium coronafaciens var. atro-
purpureum on, in U.S.A., 357.

—— , biology of Claviceps sclerotia on, 115.

— —, Septoria agropyri on, in U.S.A., 356.

— tenerum, Ustilago on, in Canada, 253.

Albizzia amara, Polyporus lucidus on, in S.
Africa, 142.

— fastigiata, Polyporus lucidus on, in S.
Africa, 142.

— moluccana, Botryodiplodia theobromae on,
in Uganda, 157.

Aleurobius farinae infesting fungus cul-
tures, 325.

Alfalfa, see Lucerne.

Alkali causes bright speck disease of
oats in Norway, 202; in relation to
Bacterium malvacearum in Arizona, 154.

Allescheria boydit on man in Texas, 226,

Allium ascalonicum, see Shallot.

— cepa, see Onion.

— porrum, see Leek.

— sativum, see Garlic.

Almond (Prunus amygdalus), Bacterium
cerasi on, in California, 393.

—, Exoascus deformans on, in New Zea-
land, 373.

—, Puccinia pruni-spinosae on, in New
Zealand, 320.

Alnus viridis, ectotrophie mycorrhiza of,
283.

Aloe arborescens, Polyporus sanguineus on, in
S. Africa, 142.

— marlothii, Polyporus sanguineus on, in
S. Africa, 142.

Alopecurus myosuroides, biology of Clavi-
ceps sclerotia on, 115.

Alternaria on broccoli in U.S.A., 301.

— on citrus in California, 541.

— on cucumber in California, 152.

— on dates in Arizona, 154.

— on lemons in California, 393.

— on orange in N.S. Wales, 354.

— on rice in U.S.A., 335.

a on

GENERAL INDEX 599

[Alternaria] on sugar-beet in Korea, 524.

— atrans, on cowpeas and soy-beans in
Arizona, 250.

— brassicae on cabbage in Trinidad, 335.

— — var. citri, biometrics of, 391.

— citri on citrus in California, 543.

— — on oranges in U.S.A., 214, 309.

— oleracea on broccoli, cabbages, and
cauliflowers in California, 302.

— radicina on carrots in U.S.A., 5.

— solani, factors influencing spore ger-

mination of, 516.

—-— on potato in Bermuda, 306, 386 ;
in Canada, 26; in Dutch E. Indies,
422; in Missouri, 573; in Morocco,
54; in Nebraska, 386 ; in New Jersey,
109.

— — on tomato in Dutch E. Indies,
422 ; in Germany, 201.

— — on various Solanaceae in Dutch E. ©

Indies, 422.
— tenuis on timber in U.S.A., 185, 186.

Amaranthus retroflecus, cucumber mosaic |

transmissible to, 513.

Amelanchier asiatica, Gymnosporangium
idetae on, in Japan, 238.

— canadensis, Bacillus amylovorus on, 163.

Ammonia as a cause of staling in fungus
cultures, 330.

Amoeba causing Fiji disease of sugar-
cane, 234,

Amoeba laciucae in latex of lettuce, 177.

Amoebae from plant latex, inoculation |
of cats with, 230 ; inoculation of mice >

with, 229, 424.

— in latex of Apocynaceae, Asclepia- |

daceae, Urticaceae, and fig, 177; of
Euphorbias, 176, 229.

— of human dysentery, action of plant
latex on, 523.

Amylase, influence of acidity on, of
Aspergillus niger, 23, 24 ; production by
Aspergillus niger, 331; in spores of
Rhizopus, 419.

Anacardium occidentale, Fusarium udum on,
in Uganda, 163.

Anamas sativus, see Pineapple.

Andropogon sorghum, see Sorghum,

— — saccharatus, Rhizoctonia ferrugena on, ‘

in Barbados, 261.

Anemone, aecidial stage of Puccinia pruni-
spinosae on, in New Zealand, 320.

Angelica, Protomyces macrosporus on, 242.

Animals transmitting plant diseases,
561.

Antirrhinum, Fusarium udum on, in
Uganda, 163.

—, Verticillium albo-atrum can infect in
Britain, 150.

Aphanomyces laevis on beet in Germany,
200.

— magnusi causing disease of crayfish in
Germany, 410. P

Aphids, Bacillus amylovorus can live in
honey dew of, 453.

—, Cladosporium aphidis may control, 413.

—, transmission of cucumber mosaic by,
513; of hop mosaic by, 382; of sugar-
cane mosaic by, 34; of tomato mosaic
by, 40; of potato leaf roll by, 291; of

spindling tuber disease of potato in
U.S.A. by, 387.

Aphis adusta, see A. maidis.

— maidis, food plants of, in Java, 33,
34, 236; in Porto Rico, 390; trans-
mission of sugar-cane mosaic by, 33,
34, 236, 241, 381, 390, 524, 585.

— rubiphila, transmission of raspberry
mosaic, and leaf curl disease by, 548.
— sacchari, possible transmission of

sugar-cane mosaic by, 237, 339.

Apium graveolens, see Celery.

Aplanobacter dissimulans on tomato, 347.

— michiganense on tomato, 246, 347.

— rhizoctonia on lettuce in Ohio, 445.
Apocynaceae, amoebae in latex of, 177 ;
action of latex of, on protozoa, 523.
Apoplexy of the vine in France, 326,

437, 528.

Aposeris foetida, Protomyces kreuthensis on,
243.

Aposphaeria pinea stated to be same as
Ceratostomella pini, 342.

— pulviscula on Salix alba in Holland, 94.

— sepulta on citrus in Spain, 405.

Apple (Pyrus malus), Armillaria mellea on,
in Canada, 304; in S. Australia, 353.

—, Bacilius amylovorus on, in Canada,
304; in Montana, 125, 439; in New
Zealand, 273; in Ohio, 505; in
U.S.A., 163; varietal resistance to,
in U.S.A., 125.

—, bitter pit of, 164.

— blotch in N. S. Wales, 354.

—, Botrytis on, in storage in New Zealand,
128.

—, brown bark spot of, in U.S.A., 221.

—, brown heart of, 124.

—, chlorosis of, in 8. Africa, 353.

—, Coniothecium chomatosporum on, in
Queensland, 122; in S. Africa, 271;
in S. Australia, 292.

—, cool storage troubles of, in Australia,
124; in New Zealand, 123, 316; in
U.S A., 455.

—, Corticium salmonicolor on, in Mauritius,
203.

— diseases, control of, in Illinois, 453 ;
in Ohio, 505; in U.S.A., 225.

—, flesh collapse of, in New Zealand,
317.

—, Fusarium putrefaciens on, in Switzer-
land, 302.

—, — willkommii on, in Denmark, 218 ;
in Oregon, 90, 206.

—, Fusicladium dendriticum on, see Venturia
inaequalis,

—, Gloeosporium malicorticis on, in Queens-
land, 123.

—, Glomerella on, in storage, 123.

—, — cingulata on, in Illinois, 454; in
New York, 546; in Ohio, 505.

—, Gymnosporangium on, carried by
junipers, 563.

—, — juniperi-virginianae on, in New
York, 546 ; in Pennsylvania, 445.

—, — yamadae on, in Japan, 237.

—, internal browning of, in U.S.A., 268.

—, leaf edge disease of, in Denmark,
488,

600

[Apple], Leptothyrium pomi on, control in
Connecticut, 220; in Ohio, 505 ; in S.
Africa, 536; injury caused by, in S.
Africa, 536.

— mildew, see Podosphaera leucotricha and
P. oxyacanthae.

—, Myxosporium corticolum on, in England,

—, Nectria coccinea on, in Oregon, 90;
differences between N. gailigena and,
90.

—, — galligena on, in Britain, 318; in
the Crimea, 172; in Oregon, 206;
differences between N. coccinea and,
90; Fusarium willkommii, conidial stage
of, 90, 218; Venturia inaequalis aids
infection by, 318.

—, Neofabraea malicorticis on, in Oregon,
206.

—, Nummularia discreta on, in Illinois,
270.

—, oiled wraps for storage of, 68.

—, Penicillium on, in New Zealand, 123.

—, — expansum on stored, in U.S.A.,
456.

—, — glaucum on, in Denmark, 218.

—, Phacidiella discolor on stored, in
Switzerland, 273.

—, Phoma stage of Contothectum chomato-
sporum on, in Queensland, 123.

—, Phoma pomi on, in Ohio, 442, 505.

—, Phomopsis mali on, in California,
393.

—, Phyllosticta briardi on, in Astrakhan,
535.

—, — solitaria on, in Illinois, 454; in
Indiana, 455; in Ohio, 442, 505; in
Pennsylvania, 444.

—, Physalospora cydoniae on, control in
Connecticut, 220; in Illinois, 454;
in Ohio, 505; in Pennsylvania, 444;
occurrence in Astrakhan, 535.

—, Phytophthora cactorum on, in U.S.A.,
433.

—, — syringae on, in Ireland, 182.

—, Podosphaera leucotricha on, control in
Germany, 121,131, 220, 223, 269 ; occur-
rence in Britain, 209; in Germany,
201, 220, 223, 269; in Italy, 294;
varietal resistance to, in Germany,
120.

—, — oxyacanthae on, in Tasmania, 305;
probably in Italy, 294.

— scab, see Venturia inaequalis.

— scald, distinct disease from brown
heart, 124 ; occurrence in New Zealand,
123; use of oiled wraps to prevent, in
U.S. A., 455; varietal susceptibility to,
in U.S.A., 456.

—, Schizophyllum commune on,
Africa, 271; in U.S.A., 90.
—, Sclerotinia cinerea f. mali on, in

England, 547.

—, —fructigena on, in N.S. Wales, 120.

—, Sclerotiwm on, in S, Africa, 110.

—, sour sap of, in N.S. Wales, 353.

—, Sphaeropsis malorum on, see Physalo-
spora cydoniae.

—, spray injury to, in Denmark, 488.

—, Stereum purpureum on, in Britain,

in S.

GENERAL INDEX

209; in New Zealand, 68; in S.
Africa, 451.

[Apple], Venturia inaequalis on, ascospore
ejection in, 122; associated with
Nectria galligena in Britain, 318 ; con-
trol in Arkansas, 440 ; in Britain, 376;
in Canada, 255, 304 ; in Connecticut,
220; in Germany, 169; in Illinois,
453; in Michigan, 71, 371; in Mon-
tana, 489; in New Hampshire, 281;
in N. S.Wales, 553 ; in New York, 506 ;
in New Zealand, 121; in Ohio, 442,
505; in Wisconsin, 257, 492; occur-
rence in Arkansas, 440; in Astrakhan,
207, 5385; in Canada, 255, 304; in
Connecticut, 220 ; in the Crimea, 172 ;
in Germany, 169; in Massachusetts,
440 ; in Michigan, 371; in Montana,
439; in New Hampshire, 281; in
N.S. Wales, 353; in New Zealand,
121, 122, 123; in Ohio, 442, 505; in
Wisconsin, 257, 492 ; spreads in cool
storage, 123; toxic action of sulphur
on, 281 ; varietal susceptibility to, in
Massachusetts, 440.

Apricot (Prunus armeniaca), Bacillus amylo-
vorus on, in U §.A., 163.

—, Bacierium cerasi on, in California, 393.

—, chlorosis of, in S. Africa, 353.

—, Exoascus deformans on, in New Zea-
land, 3738.

—, Ganoderma sessile on, in Argentina, 17.

—, gummosis of, in France, 119.

—, leaf edge disease of, in Denmark,
488.

—, Puccinia pruni-spinosae on, in New
Zealand, 320.

—, Schizophyllum commune on, in 8. Africa,
271.

—, Sclerotinia fructigena on, in N.S.
Wales, 120.

—, Stereum purpureum on, in New Zea-
land, 68; in S. Africa, 451, 452.

— (Japanese), see Prunus mume.

Arachis hypogaea, see Groundnut.

Arbutus unedo, stem tumours of, 136,

Areca palm (Areca catechu), Phytophthora
arecae on, in Mysore, 22, 563.

Arenaria, Melampsorella caryophyllacearum
on, 431.

Armillaria on cinchona in Dutch E.
Indies, 9.

— on tea in Dutch E, Indies, 9.

— fuscipes on Acacia and tea in Ceylon,
295.

— mellea, biology of, 431.

— —, enzymes of, 284,

— — on apple in Canada, 304; in S.
Australia, 353.

— — on birch in the Pyrenees, 431.

— — on cherry in U.S.A,, 481.

— — on chestnuts in the Pyrenees, 431,

— — on citrus in N.S. Wales, 354.

— — on coffee in Uganda, 409.

— — on conifers in U.S.A., 531.

— — on cork oaks in the Pyrenees, 431.

— —on fruit trees in U.S A., 481.

— —on oaks in US.A., 481.

— — on pears, varieties resistant to, in
California, 394,

GENERAL INDEX

[Armillaria mellea] on Pinus insignis in S.
Australia, 298.

— — on Pinus maritima in France, 431.

— — on raspberry in U.S.A., 278.

Arrhenatherum elatius, biology of Claviceps
sclerotia on, 115.

Arsenates, fungicidal value of, 168, 169.

Artocarpaceze, action of latex of, on
protozoa, 523.

Artocarpus incisa, see Bread-fruit.

Aschersonia aleurodes parasitic on scale
insects, 369.

— cubensis parasitic on various insects,
in Florida, 369.

— flavocitrina parasitic on white fly in
Florida, 369.

— turbinata parasitic on scale insects
and white fly in Florida, 369.

Asclepiadaceae, action of latex of, on
protozoa, 525.

Asclepsias, amoebae in latex of, 177.

—, cucumber mosaic transmitted from,
in U.S.A., 106

— syriaca, cucumber mosaic transmis-
sible to, 512.

Ascochyta boltshauseri, see Stagonosporopsis
hortensis.

— citrullina identical with A. cucumis,
342.

— cucumis, notes on, 342.

— gossypii on cotton in Arkansas, 215,
441,

— lycopersici on tomatoin Denmark, 448;
in Germany, 201.

— melonis identical with A. cucumis, 342.

— pisi on bean in New Zealand, 505.

— — on peas in Denmark, 487;
New Zealand, 505.

— — on lucerne in Norway, 202.

— — on lupin in New Zealand, 505.

— — on vetch in New Zealand, 505.

Ash (Fraxinus), infection of, by Pseudo-
monas savastanoi, 12.

—, mosaic disease of, in England, 489.

—, Septobasidium bogoriense on, in Java,
145

in

—, Torula ligniperda on, in U.S.A., 34.

Aspen (Populus tremula), Fomes igniarius
on, in Utah, 97.

Aspergillus, hyphal growth of, 588.

— on timber in U.S.A., 185.

— luchuensis on leather, 244.

— niger, diastase of, 330.

— —, influence of acidity on amylase of,
23, 24.

— —, nutrient requirements of, 82.

— — on figs in California, 150.

— — on timber in U.S.A., 186.

— repens, action of temperature and CO,
on, 25.

Aster, Coleosporium on, in U.S.A., 349.

—, Phytophthora omnivora on, in Switzer-
land, 303.

—, stem blight of, in Canada, 255,

— wilt in N.S. Wales, 354.

Asterocystis radicis, Chytridiaceous fungus
allied to, on various plants in Italy,
173.

Aureobusidium, fungus on vine resem-
bling, in N. S. Wales, 354.

x

601

[Aureobasidium], systematic position of,
7.

— vitis on vine in Australia, 152; in
France, 153.

Auricularia auricula-judae on tea in India,
343.

— mesenterica, ash analysis of, 284,

Avena sativa, see Oats.

— spp., Leptosphaeria avenaria on. in
Wisconsin, 159.

Avocado pear (Persea gratissima), die-back
of, in Hawaii, 321.

— —, Oidium on, in Bermuda, 306.

Bacillus amylobacter associated with rot-
ting of potato, 91.

— amylovorus, biology of, 452; control
of, in New Zealand, 274; dissemina-
tion of, 125, 274, 452; hosts of, 163 ;
legislation against, in Australia, 395 ;
in New Zealand, 144, 274; occurrence
in British Columbia, 395; in New
York, 546; in New Zealand, 273.

——on apple in Canada, 304; in
Montana, 125, 439; in New Zealand,
273 ; in Ohio, 505; varietal resistance
to, in Montana, 125.

— — on pear, control of, in California,
125, 394, 546; in New Zealand, 2738;
in U.S.A., 274; disseminated by bees,
125; occurrence in Canada, 304; in
New Zealand, 273; in U.S.A., 125,
163, 274, 394, 546; varietal resistance
to. in California, 126; in Montana,
125; in-U.S.A., 274, 394.

| — — on quince in Montana, 125; in

|
|

a.

U.S.A., 163.

— —, Pyrus calleryana, P. serotina, and
P. ussuriensis resistant to, 125, 274,
275.

— aroideae on tomato in Virginia, sprays
against, 346.

— atrosepticus on potato, biology and
morphology of, 85; causes rolling of
the leaf in France, 568; occurrence in
Canada, 26, 332, 465; in Denmark,
488; in Dutch E. Indies, 423; in
Germany, 200; in Manitoba, 424; in
Nebraska, 386; in Norway, 202.

— bussei on swedes and other roots in
Germany, 200.

— carotovorus on cabbage in Bermuda,
306 ; in Trinidad, 335.

— — on tomato in England, 347.

— — on turnip in Bermuda, 306; in
Norway, 203.

— — on violet in England, 119.

— — pathogenic to frogs, 446.

— coli in relation to bud rot of coco-nut
in Cuba, 268.

— croci on saffron crocus in Japan,
427.

— D, F, and flavidus causing top rot of
sugar-cane in Argentina, 338.

— lacerans on swedes and other roots in
Germany, 200,

— lathyri, Bruchus rufimanus probably
transmits to broad beans, 100.

— — on broad bean and sweet pea in
England, 99.

a)

~

602

[Bacillus lathyri] on tomato, control, 100,
430 ; occurrence in Denmark, 246; in
England, 99, 347; in New Zealand, 430;
in Pennsylvania, 443 ; seed dissemina-
tion of, 443.

— maculicola on tobacco in Switzerland,
303

— mesentericus associated with Phoma
Jerraristi on tomato, 91.

— mycoides, Chermes transmits, 561.

— vnelliae on parsley in the Philippines,
445,

— phytophthorus, see B. atrosepticus.

— pseudozoogloeae on tobacco in Dutch E,
Indies, 9.

— solanisaprus, see B. atrosepticus

— spongiosus on cherry in Germany,
201.

— spp. in top rot of sugar-cane in
Argentina, 338.

— tracheiphilus on watermelon in U.S.A.,
280.

Bacteria causing tumours of
sempervirens in France, 95.
—, effect of, on raw and textile cotton,

544,

— normally present in roots of Phanero-
gams, 327.

— on diseased elms in Holland, 2.

— on diseased maize in U.S.A., 106.

—, protection of stored fruit against,
67.

— transported in soil by nematodes,
561,

Bacterial disease of bean in Switzerland,
303.

— — of cannas in Ceylon, 7.

— — of cherry in Holland, 53.

— — of cucumber in Germany, 201.

— — of lettuce in Arizona, 154; in
Switzerland, 303 ; in Texas, 256.

— — of peas in Switzerland, 303.

— — of pepper in Dutch E. Indies,
88

Sequoia

— — of prickly pear in Australia and
Florida, 397.

— — of tomato in Switzerland, 303.

— diseases of Philippine plants, 444.

— — of tomato in Pennsylvania, 443.

— fixation of nitrogen in leaves of
Rubiaceae, 418.

— ring disease of potato in Dutch
E. Indies, 422; in India, 333; in
Norway, 202.

— rot of cotton bolls in S. India, 367.

— — of maize in Arkansas, 441,

— — of potato in Canada, 465.

— —of sugar-cane setts in Argentina,
339.

— spot of cabbage (suspected) in Holland,
54.

— — of chilli pepper in Georgia, 196,
197.

Bacterium causing leaf-scald of sugar-
cane in Australia, 579.

— angulatum, action on various sugars,
158.

— — on tobaeco, control in Virginia,
245 ; dissemination, 245, 476; occur-
rence in the Transvaal, 477; in

GENERAL INDEX

Virginia, 244;
476.

[Bacterium] aptatum on sugar-beet in
Korea, 524.

— araliavorus on ginseng in Korea, 502.

— campestre, see Pseudomonas campestris.

— cerasi on stone fruits in California,
393.

— citrarefaciens, see B. citriputeale.

— citriputeale, B. citrarefaciens identical
with, 392.

— — on citrus in California, 392, 5438.

— — on Quercus wislezenii in California,
393.

— coronafaciens on oats (suspected) in
Britain, 208, 401.

— — var. atropurpureum on brome grass,
oats, and Agropyron repens in U.S.A.,
357.

— destructans, see Pseudomonas destructans.

— erodii on pelargonium, 371.

— exitiosum on tomato in Denmark, 246;
in Pennsylvania, 444.

— glycineum, action on various sugars,
158.

— hibisci on Hibiscus in Japan, 413.

— lacrymans on cucumber, 152, 196.

— malvacearum on cotton in the Philip-
pines, 445 ; relation to alkali in Ari-
zona, 154; seed disinfection against,
in Arizona, 154, 217.

— mori on mulberry in S. Australia, 292.

— olivae on olives in Italy, 322.

— panaxi on ginseng in Korea, 502.

— pelargonii on pelargonium in U.S.A.,
370.

— phaseoli, see Pseudomonas phaseoli.

— radicicola, galls caused by, 378.

— savastanoi, see Pseudomonas savastanot.

— sojae action on various sugars, 158.

— solanacearum on Chrysanthemum coro-
narium in the Philippines, 262.

— — on eggplant in the Philippines,
261, 262, 445. :

— — on groundnut in Dutch E. Indies,
9, 351.

— — on Hibiscus cannabinus in Sumatra,
314.

— — on Lantana aculeata in Sumatra,
346.

— —, Mimosa invisa highly resistant to,
in Sumatra, 295, 346.

—-— on potato in Dutch E. Indies, 8,
423 ; in India, 333.

—— on soy-beans in Dutch E. Indies, 10.

— — on Stachytarpheta indica in Sumatra,
35.

— — on tobacco in Dutch E. Indies, 8 ;
in Florida, 474; in the Philippines,
109, 261, 445; in Sumatra, 35, 295,
314. ‘

— — on tomato in Norway, 203; in
Pennsylvania, 444; in the Philip-
pines, 261, 445; in Sumatra, 35.

— — on wild hosts in Sumatra, 346.

— tabacum action on various sugars, 158.

— — on tobacco, 476; control, 38, 39,
345, 474, 476; occurrence in Carolina,
473; in Connecticut, 37; in Florida,
474; in Massachusetts, 440; in S.

soil infection with,

a
|
|
!

GENERAL INDEX

Africa, 37, 476; in Virginia, 245; in
Wisconsin, 345; viability of, 38, 40.
[Bacterium] tumefaciens, appositional

growth in galls caused by, 55.

_— —, differentiation from Pseudomonas

savastanoi, 12.

— —, effect of X-rays on, 494.

— —, fasciation of cabbage, castor,
nasturtium, pelargonium, and tobacco
produced by, 10.

— —, gall-formation by, 55, 378, 396,
494,

— —, induced resistance of Chrysanthe-
mum and rose to, 355.

— -— in New York, 546.

— —, legislation against, in Washing-
ton, 278.

— — on marguerites in Denmark, 488.

— — on raspberry in Lllinois, 219; in
Washington, 278; in Wisconsin, 493.

— — on sugar-beet in Korea, 524.

— — on vine in France, 532.

— —, varietal resistance of Prunus to, in
California, 394.

— vascularum on sugar-cane, control by
drainage in Queensland, 428; occur-
rence in Australia, 140, 354, 579;
varietal resistance to, 140, 579.

— vignae on cowpea in Indiana, 485.

Baioud or white disease of date palm in
Algeria, 328.

Bajra, see Pennisetum typhoidewm.

Bakerophoma sacchari on sugar-cane in the
Philippines, 109.

Banana (Musa sapientum), bunchy top of,
in N.S. Wales, 131, 354, 372.

—, Fusarium cubense on, in Panama, 321 ;
in the Philippines, 108; in St. Lucia,
261; in the West Indies, 217. (See
also Panama disease of).

—, Gloeosporium musarum on,
Philippines, 279. -

—, heart rot of, in the Philippines,
108.

—, Panama disease of, 108, 131, 217,
261, 321, 354, 372.

—, Phoma musae on, in the Philippines,
108.

—, Pseudomonas musae in relation to
Panama disease of, 217.

— wilt in Java and the West Indies,
217; in Panama, 321. (See also
Panama disease of).

Barberry (Berberis) eradication, arsenite
and salt formulae for, 399; effects on
Puccinia graminis in Denmark, 199,
487, 499; in U.S.A, 106, 399, 439; in
Western Europe, 499 ; legislation for,
in Denmark, 199; in U.S.A., 106.

—. Puccinia graminis on, in Australia,
307; in Canada, 303; in Denmark,
199, 487; in Europe, 499.

Barley (Hordeum), bright speck disease
of, in Denmark, 488.
—. Erysiphe graminis on,
487, ,
—, finger-print disease of, in Norway,

202.

in the

in Denmark,

—, Fusarium on, in Denmark, 487,
—, — hordearum on, in Morocco, 54.

603

[Barley], Gibberella saubinetii on, in Hol-
land, 53

—, Helminthosporium on, in Holland, 53.

—, — gramineum on, in Austria, 538 ; in
California, 61 ; in Germany, 161, 169,
200 ; in N. Dakota, 498 ; in Norway,
202; in Wisconsin, 491; perithecia
of, 53, 61; seed treatment against, in
Austria, 588; in Germany, 399, 416,
509, 511, 552. (See also Pleospora tri-
chostoma).

—, — oryzae on, in Japan, 321.

—, — sativum on, in California, 61.

—, — teres on, in Germany, 200. (See
also Pleospora teres).

—, Leptosphaeria on, in Denmark, 487.

—, mycorrhiza of, in Italy, 172, 173.

—, Ophiobolus on, in Denmark, 487.

—, Pleospora graminea, see P. trichostoma.

—, — teres on, in Denmark, 487. (See

also Helminthosporium teres).

, — trichostoma on, in Denmark, 487;

on germinated grain of, in Holland,

53. (See also Helminthosporium grami-

neum).

—, Pseudomonas alboprecipitans can infect,
447,

—, Rhynchosporium secalis on, in Canada,
304; varietal resistance to, in Cali-
fornia, 392.

— seed steeps in Germany, 511.

—, Septoria passerini on, in Italy and
U.S.A., 356.

—, spot necrosis of, in Norway, 202.

—, Typhula graminis on, in Germany, 58.

—, Ustilago hordei on, chemotherapeutical
studies of, 551, 553; control in Ger-
many, 161, 170; in Sweden, 19; in
U.S.A., 458; in Wales, 400; effect of
ultraviolet and X-rays on, 324 ; occur-
rence in Denmark, 487; in Germany,
161; in Sweden, 19.

—, — nuda on, control in Austria, 538 ;
in Germany, 400; in U.S.A., 458;
effect of ultraviolet and X-rays on,
324; influence of fertilizers on, in
Germany, 504.

Basidiomycetous fungus
asphalt shingles, 187.

Basisporium gallarum in cultures from
maize, dewberry, and wheat, 296,

— — on tomato in California, 296.

Basswood (Tilia americana), Torula ligni-
perda on, in U.S.A., 34.

Bean, Ascochyta boltshauseri on, see Sta-
gonosporopsis hortensis.

—, — pisi on, in New Zealand, 505.

—, bacterial disease of, in Switzerland,
303.

—, Bacterium phaseoli on, see Pseudomonas
phaseoli.

—, Bacillus lathyri on broad, in Britain,
99.

—, Botrytis on broad, affected by Bacillus
lathyri in England, 100.

—, Cercospora fabae on broad, 342.

—, Colletotrichum lindemuthianum on, con-
trol with uspulun, 20; occurrence in
Bermuda, 306; in Trinidad, 3365.
(See also Glomerella lindemuthianum).

destroying

604 GENERAL’ INDEX

[Bean], effect of Bordeaux mixture on
chlorophyll of, 323.

—, Erysiphe polyyoni on, in Bermuda,
306 ; use of ‘ Pri’ sulphur against, in
Germany, 171.

—, Glomerella lindemuthianum on, in Den-
mark, 488.

—, Isariopsis griseola on, in Holland,
54.

— (Lima), see Phaseolus lunatus.

— mosaic in Norway, 203; protozoa
associated with, in U.S.A., 227, 514:
transmission of, by Macrosiphum solani-
Solii, 77.

— Pseudomonas phaseoli on, in Bermuda,
306; in Norway, 203; in the Philip-
pines, 445.

—, Rhizoctonia on, in Trinidad, 335.

—, Sclerotinia libertiana on, in Bermuda,
306.

—, slime bodies in relation to mosaic of,
514, 515.

—, Stagonosporopsis hortensis on, in Nor-

way, 203.

—, stimulating effect of Bordeaux mix-
ture on, 507.

—, Uromyces fabae on, in Morocco, 54.

Beauveria densa (Isaria densa) on cock-
chafers in France, 412.

— globulifera, see Sporotrichum globuliferum.

Beech (Fagus sylvatica), Mycelium radicis
fagi in mycorrhiza of, in Germany,
463.

Beet (Beta vulgaris), Actinomyces on, in
Norway, 203.

—, — scabies on, in Czecho-Slovakia,
466.

—, Alternaria on, in Korea, 524

—, Aphanomyces laevis on, in Germany,
200.

—, Bacterium aptatum on, in Korea, 524.

—, — destrucians on, see Pseudomonas de-
structans. 7
—, — tumefaciens on, in Korea, 524.

—, bright speck disease of, in Denmark,
488.

—, Cercospora beticola on, in Japan, 485;
in Korea, 524; in Morocco, 54; seed
borne dissemination of, 198; vitality
of, 485.

—., Colletotrichum omnivorum on (suspected),
in Korea, 524.

—, Corticium solani on, in Denmark, 487 ;
in Korea, 524.

—, effect of seed disinfectants on, in
Brunswick, 224, 510;. in Hungary,
18.

— mosaic in Britain, 208; in Denmark,
487.

—, Oidium on, in France, 101.

—, Peronospora schachtii on, in Denmark.
487, 563; in Germany, 485; in Hol-
land, 538; overwinters in host tissues,
485 ; spread of, 484,

—, Phoma on, in Bavaria, 510; in U.S.A.,
89.

—, — betae on. control in Germany, 224 ;
in Korea, 524; disseminated on seed,
198, 524; heart rot attributed to, 466,
484; occurrence in Czecho-Slovakia,

466 ; in Denmark 487;
200, 224; in Korea, 524.
[Beet], Physarum cinereum on, in Korea,

in Germany,

—, Pseudomonas destructans on, in Korea,
524,

—, Pythium de Baryanum on, in Denmark,
487 ; in Germany, 200, 224.

, Rhizoctonia on, in Korea, 524.

—, — violacea on, in Czecho-Slovakia,
467 ; ; in Holland, 53.

— root rot caused by soil conditions in
Czecho-Slovakia, 466.

—, Sclerotium rolfsii on, in Korea, 524.

—, Septobasidium mompa on, in Korea,
524.

—, Uromyces betae on, in Morocco, 54.

— (wild), Peronospora schachtii and Uvro-
myces betae on, in Denmark, 563.

Berberis, see Barberry.

Berseem (Trifolium alexandrinum), legisla-
tion against importation of, in India,
240.

Beta maritima, Oidiwm on, in France,
101.

— vulgaris, see Beet and Mangold.

Betula, see Birch.

‘Bios’, action on yeast of, 284.

Birch (Betula alba), ‘ Wisa’ disease of,
in Finland, 349.

—, Armillaria meliea on, in the Pyrenees,
431.

Bitter pit of apple, cause of, 164.

Blackberry (Rubus), eastern blue stem
disease of, in U.S.A., 129.

— mosaic in New York, 352.

‘ Boixat’ disease of garlic in Spain, 191.

Boletus cryptarum, see Fomes cryptarum.

— elegans forms larch mycorrhiza in
Sweden, 77, 78.

Boraginaceae, specialization of Erysiphe
horridula on, 180

Bordeaux mixture causing second growth
of potato tubers in Missouri, 466.

— —, effect of, on the chlorophyll of
the bean, 323.

— —, stimulatory action of, 507.

— oil emulsion for control of citrus
diseases, 204, 206, 363, 364, 367, 539.
Botryodiplodia theobromae on Albizzia moluc-

cana, in Uganda, 157.

— — on cacao in Trinidad, 110.

— — on sugar-cane in Cuba, 525.

— — on tea in India, fungicides against,
343, 344. (See also Thyridaria tarda).
Botrytis, apical growth of hyphae of,

588.

— on apple in store in New Zealand,
123.

— on broad bean affected iby Bacillus
lathyri in England, 100.

— on elm in Holland, 2.

— on narcissus in England, 489.

— on pine seedlings in U.S.A., 5.

— on tomato in Denmark, 246; in
England, 490.

— cana, relation of, to Sclerotiwm cepi-
vorum, 191.

— cinerea, effect of temperature and CO.
on, 25; of sulphur on, 460.

)

E GENERAL INDEX 605

[Botrytis cinerea}, factors influencing spore
germination of, 516.

— — on citrus in California, control
of, 540, 542.

— — on flax in Holland, 53.

— —on lemon in California, 540, 542.

— — on lupin in New Zealand, 504.

— — on peach in Holland, 94.

— — on tomato in England, 347.

— — on vine in France, 532; in
Switzerland, 45, 302.

— stephanoderis parasitic on Cricula tri-
fenestrata and Stephanoderes hampei in
Dutch E. Indies, 369.

— vulgaris on citrus in Spain, 405.

Brachiaria platyphylla susceptible to sugar-
cane mosaic, 584, 585.

Brachybasidium pinangae on Pinanga kuhlii;
341.

Brachypodium sylvaticum, biology of Clavi-
ceps sclerotia on, 115.

Brachysporium trifolii, mutation of, 76.

Bramble, see Blackberry.

Brassica, fasciation produced by Bacterium
tumefaciens in, 10.

—, Pseudomonas campestris on, in Norway,
203.

— alba, see Mustard. e

— campestris, see Turnip and Swede
Turnip.

— — var. sarson, see Mustard (Indian).

— chinensis, see Cabbage (Chinese).

— nigra, see Mustard.

— oleracea, see Cabbage, Cauliflower,
Broccoli, Brussels sprouts, Kale, Kohl-
rabi.

Bread-fruit (Artocarpus incisa), ripe rot of,
in British Guiana, 355.

Bremia lactucae on salad in Denmark,
488.

Brine used for elimination of Claviceps pur-
purea in N. Dakota, 498.

Broccoli (Brassica oleracea), Alternaria on,
in U.S.A., 301.

Brome grass (Bromus inermis), Bacterium
coronafaciens var. atropurpureum on, in
U.S.A., 357.

—, Septoria bromi on, in U.S.A., 356.

Bromus, Puccinia glumarum on, in Cali-
fornia, 392.

— ciliatus, Ustilago bromivora on, in Cana-
da, 254,

— inermis, see Brome grass,

Broussonetia papyrifera, ‘ witches’ broom’
on, in Sicily, 404.

Brown bark spot of fruit trees in U.S.A.,
221.

— bast of Hevea rubber, effect of tapping
on, 8, 155, 178, 233, 396; etiology of,
232; occurrence in Belgian Congo, 577 ;
in Dutch E. Indies, 8; in Malaya,
232, 396, 425; in S. India, 32; in
Uganda, 155; studies on, 178, 232,
425.

— heart of apples in cold storage, 124.

— root diseases of camphor and Hevea
rubber, 291, 396. (See also Fomes
lamaoensis).

Bruchus rufimanus probably transmits
Bacillus lathyri to broad beans, 100.

‘Brusone’ of rice, disease resembling,
in India, 31, 32.

Brussels sprouts (Brassica oleracea), Phoma
oleracea on, in Holland, 54.

Bryophyllum calycinum, Bacterium tume-
Jaciens on, 379.

Buckthorn, see Rhamnus cathartica.

Bud rot of coco-nut in British Guiana,
355; in Ceylon, 7; in Cuba, 268; in
Malaya, 396: in Fiji, 215, 311; in
Guadeloupe, 33; in Jamaica, 184; in
the Philippines, 109; in Surinam,
107; in Trinidad, 394.

— — of oil palm in Dutch E. Indies,
9; in Surinam, 107.

Bulbine semibarbata, Puccinia semibarbaiae
on, in S. Australia, 292.

Bulbocodium vernum, Urocystis colchici on
(suspected), in Holland, 54.

Bulrush millet, see Pennisetum typhoideum.

Bunt of wheat, see Tilletia.

Cabbage (Brassica oleracea), Alternaria
brassicae on, in Trinidad, 335.

—, — oleracea on, in California. 301.

—, Bacillus carotovorus on, in Bermuda,
396 ; in Trinidad, 335.

—, bacterial spot of (suspected), in
Holland, 54.

—, Bacterium campestre on, see Pseudomonas
campestris.

—, — tumefaciens causing fasciation of,

—, Cystopus candidus spreads from weeds
to, in Denmark, 563.

—, Erysiphe on, in Trinidad, 335.

—, Fusarium conglutinans on, in Canada,
258; in Delaware, 301; in Texas,
256; in Trinidad, 335, 486; tem-
perature relations of, 67; varietal
resistance to, 258, 301, 486.

—, Orobanche aegyptiaca on, in Astrakhan,
207.

—, Peronospora parasitica on, in Trinidad,
335.

—, Phoma lingam on, control, 104, 301;
rainfall in relation to, 105 ; seed treat-
ment for, 104,

—, Phyllosticta brassicicola on,
Australia, 292.

—, Plasmodiophora brassicae on, action of
radium on, 494; control in Germany,
222; in U.S.A., 444; earthworms as
disseminators of, 351; gall formation
by, 377, 378, 379, 494; occurrence in
Canada, 258 ; in Denmark, 487, 563; in
Germany, 222; in Norway, 203; in
Pennsylvania, 444; in Silesia, 351 ;
in Tasmania, 304 ; in Wisconsin, 258 ;
spreads from weeds to, in Denmark,
563 ; temperature and moisture re-
lations of, 258 ; treatment by uspulun,
222; varietal susceptibility to, 151,
223, 432, 512.

—, Pseudomonas campestris on, in Ber-
muda, 306,

—, Pythium de Baryanum spreads from
weeds to, in Denmark, 563.

—, Rhizoctonia on, in Trinidad, 335.

—, Sclerotinia on, in Bermuda, 806.

in S.

606 - GENERAL INDEX

[Cabbage], Chinese (Brassica chinensis),
mosaic, amoeboid bodies in, 241.

Cacao (Theobroma cacao), Calospora theo-
bromae on, in St. Thomas Island,
588.

—, Cephaleuros minimus on, in Ceylon, 7.

—, — virescens on, in Trinidad, 111.

—, ‘collar crack’ disease of, in Togoland,
210.

—, die-back of, in Trinidad, 110.

—, Diplodia (Botryodiplodia) theobromae on,
in Trinidad, 110.

—, Fomes pectinatus on, in St. Thomas
Island, 589.

—, Marasmius perniciosus on, in British
Guiana, 355.

—, ‘mealy pod’ disease of, see Trachy-
sphaera fructigena.

—, Phytophthora faberi on, in Ceylon, 7 ;
in the Gold Coast, 204; in Guade-
loupe, 33; in San Thomé, 112; in
Trinidad, 111; in West Indies, 183.

—, Polyporus zonalis on, in St. Thomas
Island, 589.

—, Poria ferruginosa on, in St. Thomas
Island, 589.

—, Rosellinia bunodes and R. pepo on, in
Trinidad, 111.

— thread blight in the Gold Coast,
204; in Trinidad, 111.

—, Trachysphaera fructigena on, in the
Gold Coast, 203, 495, 497.

—, Trametes gibbosa, T. sanguineum, T.
sepium, and T. sprucei on, in St. Thomas
Island, 589.

—, Tricholoma-like fungus on, in Togo-
land, 210.

Caeoma conigenum on pine cones in Ari-
zona and Mexico, 3.

— strobilina on pine cones in Florida
and Mississippi, 3.

Caffaro powder, effect on wheat of seed
treatment with, 322.

Cajanus indicus, see Pigeon pea.

Calamagrostis canadensis, Puccinia lolit on,
in U.S.A., 209.

— epigeios, biology of Claviceps sclerotia
on, 115.

Calceolaria, Phytophthora omnivora on, in
Switzerland, 303.

Calcium caseinate as spray spreader,
225, 375.

— cyanamide, control of cereal smuts

' by, in Germany, 503.

Calluna vulgaris, mycorrhiza of, 326.
Calonectria graminicola on cereals in Nor-
way, 202. (See also Fusarium nivale).
Calonyction, Coleosporium ipomoeae on, in

U.S.A., 348.

Calophyllum burmanni, Corticium on, in
Ceylon, 473.

Calosanthes, Septobasidium bogoriense on,
in Java, 145.

Calospora theobromae on cacao in St.
Thomas Island, 588.

Camellia, Pestalozzia guepini on, in Den-
mark, 488.

Camphor (Cinnamomum camphora), Hy-
menochaete causing brown root disease
of, 291.

| Canna, bacterial disease of, in Ceylon, 7.

Cannabis sativa, see Hemp.

Cantaloupe (Cucumis melo), Colletotrichum
lagenarium can infect, 256.

Canthium campanulatum, Hemileia canthii
teleutospores on, in Ceylon, 586.

Capnodium on tea in Java and Sumatra, 9.

— brasiliense on coffee in Uganda, 408.

— citri on citrus in Spain, 405.

Capsella bursa-pastoris, Plasmodiophora bras-
sicae on, in Germany, 223.

Capsicum inoculated with Verticillium albo-
atrum in Britain, 150,

— annuum and C. frutescens, see Chilli.

Carbon dioxide, effect of, on fruit-rotting
fungi, 24; on soil Fusaria, 382.

— — produced in fungus cultures re-
tards staling, 330.

Carex, Puccinia pringsheimiana on, in Den-
mark, 563.

Carica papaya, see Papaw. .

Carissa arduina, Macowaniella congesia on,
in S. Africa, 141.

Carnation (Dianthus), Fusarium udum on,
in Uganda, 163.

—, Vermicularia herbarum on, in France,
370.

Carrot (Daucus,carota), Alternaria radicina
on, in ae 5, 6.

—, bright speck disease of, in Denmark,

—, Macrosporium carotae on, in U.S.A.,
61, 352.

—, Sclerotinia libertiana on, in Pennsyl-
vania, 444.

Carum, Protomyces macrosporus on, 242.

Carya ovata, see Hickory.

Caryophyllaceae, Melampsorella caryopiyl-
lacearum on, 431.

Casein as spray adhesive and spreader,
225, 376, 563.

Cashew-nut, see Anacardium occidentale.

Cassava (Manihot utilissima), fungus
disease of, in Zanzibar, 355.

Cassytha. legislation against, in Zanzibar,
480.

Castanea, see Chestnut.

Castor, see Ricinus communis,

Casuarina equisetifolia, Corticum salmonicolor
on, in Mauritius, 203.

— —, ‘smut’ disease of, in Mauritius,
203.

— stricta, Ganoderma sessile on, in Argen-
tina, 17.

Cats inoculated with amoebae from latex
of plants, 230.

Cauliflower (Brassica oleracea), Alternarta
oleracea on, in California, 301.

—, Plasmodiophora brassicae on, treatment
by uspulun, 222.

Celery (Apium graveolens), Puccinia apit
on, controlled by uspulun in Ger-
many, 20.

—, Pythium on, in Bermuda, 306,

— root rot in U.SA., 109.

—, Sclerotinia libertiana on, in New Jersey,
102 ; in Pennsylvania, 444.

—, Septoria apii on, in Canada, 255; in
Morocco, 54; seed-borne dissemination
of, 198.

“— =

GENERAL INDEX 607

[Celery], Septoria petroselini var. apii on,
in Bermuda, 306.

—, uspulun stimulates germination cf
seeds of, 20.

Cellocresol, use of, against Podosphaera
leucotricha in Germany, 223.

Celtis kraussiana, Lenzites betulina and L.
guineensis on, in S Africa, 142.

— —, Trametes subflava on, in §. Africa,
142.

Cenangium abietis on Pinus strobus in Swit-
zerland, 246.

Cephaleuros minimus on cacao in Ceylon, 7.

— mycoidea on cloves in Malaya, 426.

— — on Hevea rubber in Malaya, 426.

— — on pepper in Malaya, 426; in
Sarawak, 337.

— — on tea in Malaya, 426.

— virescens on cacao in Trinidad, 111.

— — on tea in Java, 9; Septobasidium
bogoriense predisposes to attacks of, in
Java, 145.

Cephalosporium on maize in U.S.A., 106.

— on rice in India, 259,

— boydii, stage of Allescheria boydii, 226.

— sacchari on maize in Missouri, 213.

— — on sugar-cane in Barbados, 261;
in the Philippines, 109.

— stage of Graphium on elm in Holland,
2, 93.

Cephalotheciwm roseum on timber in U.S.A.,
185, 186.

Cerastium, Melampsorella caryophyllacearum
on, 431.

Ceratostomella on Pinus palustris in U.S.A.,
107.

— on timber in Scotland, 49, 50; in
U.S.A., 107, 185.

—, Sphaeronema pilifera probably identical
with, 342.

— piceae, Cladosporium and Graphium
stages of, 50.

— — oon Pinus sylvestris in Scotland,
50.

— pini on conifers in Scotland, 49;
Aposphaeria pinea identical with, 342.
Cercospora apii on parsnip in 8. Australia,

292.

— arachidis var. macrospora on groundnut
in Italy, 174.

— beticola on beet in Japan, 485; in
Korea, 524; in Morocco, 54; seed-
borne dissemination of, 198 ; viability
of, 485.

— cerasella on cherry in Astrakhan,
535; in Japan, 416. (See also Myco-
sphaerella cerasella).

— circumscissa on plum in Astrakhan,
535.

— coffeicola on coffee in Uganda, 156,
408.

— columnaris synonymous with Isariopsis
griseola, 342.

— fabae on Vicia faba similar to C.
rautensis on Coronilla, 342.

— juncina, differences between Cercospo-
rina juncicola and, 281.

— kopkei on sugar-cane in Cuba, 525; in
the Philippines, 109.
melonis on cucumber in Denmark, 488.

[Cercospora] nicotianae on tobacco in Fleri-
da, 475; in the Philippines, 109.

— persunata on groundnut in Dutch E.
Indies and Africa, 351.

— phaseolorum not related to C. columnaris,
342.

— rauiensis on Coronilla similar to C.
fabae on Vicia faba, 342.

— sacchari on sugar-cane in Australia,
580.

— vaginae on sugar-cane in Barbados,
261 ; in Cuba, 525.

— violae on violet in Morocco, 54.

Cercosporella theae on Acacia and tea in
Ceylon, 294, 473.

Cercosporina juncicola on Juncus in Japan,
281.

Chaetochloa lutescens, Pseudomonas alto-
precipitans on, in Arkansas, 447.

— —and C, magna susceptible to sugar-
cane mosaic, 584, 585.

Chaetomium on timber in U.S.A., 185,
186.

Cheiranthus cheiri, see Wallflower.

Chemotherapeutical index of fungicides,
551, 552, 554, 557.

Chenopodium, Peronospora on, in Mauritius,
203.

— album, Thielavia basicola on, in Ireland,
117,

Chermes transmits Bacillus mycoides, 561.

Cherry (Prunus cerasus), Armillaria mellea
on, in U.S.A., 481.

—, Bacillus amylovorus can live in nectar
of, 453.

—, — spongiosus on, in Germany, 201.

—, bacterial disease of, in Holland, 53.

—, Bacterium cerasi on, in California, 593.

—, black knot of, in S. Australia, 353.

—, brown bark spot of, in U.S.A., 221.

—, Cercospora cerasella on, in Astrakhan,
353 ; in Japan, 416.

—, Coccomyces hiemalis on, control in
Canada, 258 ; in U.S.A., 73, 454, 492 ;
occurrence in New York, 546.

—, Cylindrosporium padi on, in N.S.
Wales, 354; in U.S.A., 110.

—, Exoascus minor on, in New Zealand,
373.

—, Fusicladium cerasi on, in Germany,
201.

—, Gnomonia erythrostoma on, in Switzer-
land, 277.

—, gummosis of, in France, 120.

—, Monilia on, in Germany, 201, 457;
varietal resistance to, in Germany,
457.

—, Mycosphaerella cerasella on, in Japan,
416.

—, Puccinia pruni-spinosae on, in New
Zealand, 320.

—, Sclerotinia cinerea on, control in Illi-
nois, 454.

—, — — f. pruni on, in England, 547.

—, — fructigena on, control in Australia,
276 ; occurrence in Crimea, 172.

—, Taphrina minor on, see Exoascus minor.

Chestnut (Castanea), Armillaria meilea on,
in the Pyrenees, 431.

—, Cronartium conigenum on, in U.S.A.,3.

608

{Chestnut, Cronartium] strobilinum on, in
U.S.A., 3.

— diseases, control by use of immune
varieties, 512.

—, Endothia parasitica on, danger of intro-
ducing into Europe, 189 ; introduction
into U.S.A. and losses caused by, 148;
occurrence in China and Japan, 189 ;
in U.S.A., 107, 148, 191, 481; varietal
resistance to, 107, 481.

—, Fusicoccum on, in California, 190.

— ink disease in France, 188, 481.

—, Mycelophagus castaneae believed to
cause ink disease of, 188.

Chickweed, see Stellaria.

Chicory (Cichorium intybus), Sclerotinia
libertiana on, in the Pyrenees, 193.

Chilli (Capsicum annuum and C. frutescens),
bacterial spot of, in Georgia, 196, 197.

—, cucumber mosaic can infect, 512.

—. Diplodia lycopersici on, in Holland, 54.

—. Phytophthora capsici on, in New
Mexico, 101.

Chionanthus virginica, Pseudomonas sava-
stanoi can infect, 12.

Chlorosis of fruit trees in Crimea, 172 ;
in S. Africa, 353; treatment of, 172,
3538, 552.

— (‘Sand drown ’) of maize and tobacco
caused by magnesium deficiency in
U.S.A., 80, 421.

— of vine, treatment of, 552.

Chomelia asiatica, nitrogen fixing leaf
nodules of, in Ceylon and India, 418.

Chromosporium maydis identical with
Penicillium crustaceum, 167. *
Chrysanthemum alpinum, Protomycopsis

chrysanthemi on, 248.

— coronarium, Bacterium solanacearum on,
in the Philippines, 262.

— frutescens, Bacterium tumefaciens on,
gall-formation by, 55; production of
varieties resistant to, 355.

— leucanthemi, Protomycopsis leucanthemi on,
243.

— mildew, ‘Pra’ sulphur against, in
Germany, 171.

Chrysophlyctis endobiotica, see Synchytrium
endobioticum.,

Chytridiaceous fungus in mycorrhiza of
various plants in Italy, 173.

Cichorium intybus, see Chicory.

Cinchona, Armillaria on, in Dutch E.
Indies, 9.

— canker in Dutch E. Indies, 10.

—, Corticium salmonicolor on, in Dutch E.
Indies, 9.

—, Dendrophoma cinchonae on, in Indo-
China, 96.

—, Guignardia yersini on, in Indo-China,
96.

—, Moniliopsis aderholdi on, in Dutch E.
Indies, 10.

—, Phlyctaenia cinchonae on, in Indo-
China, 96.

—, Phoma cinchonae on, in Indo-China, 96.

—, Phyllosticta cinchonaecola on, in Indo-
China, 95.

—, — honbaensis on, in Indo-China, 95.

—, — yersini on, in Indo-China, 95.

GENERAL INDEX

[Cinchona], Physalospora cinchonae on, in
Indo-China, 96.

— root disease in Dutch E. Indies, 10.

—, Rosellinia on, in Dutch E. Indies, 9.

—, Septobasidium bogoriense on, in Java,
145.

—, stem rust of, in Dutch E. Indies, 10.

Cinnamomum burmanni, see Cinnamon.

— camphora, see Camphor.

— iners, Aecidium cinnamomi on, in Java,
297.

Cinnamon (Cinnamomum burmanni), Phyto-
phthora cinnamomi on, in Sumatra, 9,
246.

Cintractia spinificus on Spinifex hirsutus,
effect of, 292.

Citromyces on timber in U.S.A., 185.

Citron (Citrullus vulgaris), Colletotrichum
lagenarium can infect, 256.

Citrullus vulgaris, see Citron and Water-
melon.

Citrus, Agaricus citri on, in Spain, 405.

—, Alternaria on, in California, 541.

—, — citri on, in California, 548.

—, Aposphaeria sepulta on, in Spain, 405.

—, Armillaria mellea on, in N. 8. Wales,
354.

—, Bacterium citrarefaciens on, synony-
mous with Bact. citriputeale, 392.

—, — citriputeale on, in California, 392,
543.

—, Botrytis cinerea on, in California, 540,
542.

—, — wulgaris on, in Spain, 405.

— canker, see Pseudomonas citri.

—, Capnodium citri on, in Spain, 405.

—, Cladosporium fumago on, in Spain,
405.

—, — herbarum on, in Spain, 405.

—, Colletotrichum gloeosporioides on, in
Spain, 405.

— collar rot in N. S. Wales, 353.

—, Corticium salmonicolor on,
Philippines, 108.

—, Dematium monophyllum on, in Spain,
405.

—, Diplodia on, in Argentina, 62; in
California, 541, 543.

— diseases in the Philippines, 108; in
Spain, 405,

—, Echinobotryum citri on, in Spain, 405.
—, entomogenous fungi for the control
of seale insects on, in Florida, 369.
—, Entomophthora fumosa parasitic on

mealy bug on, in Florida, 311.

— exanthema in N.S. Wales, 353.

—, Fusarium on, in Argentina, 62; in
California, 540, 543,

—, — limonis on, in Spain, 405.

—. greasy spot of, in the Philippines,
108.

— gummosis in Argentina, 62, 64; in
California, 541, 543; in Spain, 405.
—, Macrophoma destruens on, in Australia,

396.

—, Melanomma medium on, in Spain, 405.

— melanose, see Phomopsis citri.

—, Meliola on, in the Philippines, 108.

—, — citri and M. penzigi on, in Spain,
405.

in the

——

GENERAL INDEX 609

[Citrus], Morphea citri on, in Spain, 405.

—, mottled leaf of, in the Philippines,
108.

—, Nectria hematochroma on, in Argentina,
62.

—, Oospora hyalinula on, in Spain, 405.

—, Penicillium digitatum on, in Spain,
405 ; causes a rise of temperature in
the fruits of, 83.

—, — glaucum on, in Spain, 405.

—, — roseum on, in California, 541, 543.

—, Phoma omnivora on, in W. Australia,
395.

—, Phomopsis californica on, in California,
66

—, — citri on, control in U.S.A., 106,
363, 364, 407.

—, Physalospora citricola on, in Spain,
405.

—, Phytophthora parasitica on, in Argen-
tina, 62; in California, 540, 542; in
the Philippines, 108.

—, — terrestris on, see P. parasitica.

—, Pleosphaeria hesperidum on, in Spain,
405.

—, Polyporus obliquus on, in Spain, 405.

—, Pseudomonas citri on, eradication in S.
Africa, 352; in U.S,A., 106; intro-
duced into U.S.A. on Japanese orange,
143; not known in Italy, 404 ; occur-
rence in Mauritius, 203; in the
Philippines, 108; in S. Africa, 352 ;
infects through stomata, 63; relation
of age of host to infection, 63; varie-
tal resistance to, 63.

— psorosis in California, 542.

—, Pythiacystis citrophthora on, in Cali-
fornia, 539, 542; temperature rela-
tions of, 542; varietal resistance to,
540.

—, Rhizoctonia violacea on, in Spain, 405.

— root rot in Italy, 404.

— scab, cause and distribution, 364;
Cladosporium citri incorrect name for
cause of, 365; control, 366 ; in Florida,
363 ; in Porto Rico, 539; varietal sus-
ceptibility to, in Florida, 365.

— sealy bark in S. Africa, 352.

—, Sclerotinia libertiana on, in California,
542.

—, Septobasidium bogoriense on, in Celebes
and Java, 145.

— sooty mould in Argentina, 64 ; in the
Philippines, 108.

—, Sphaerella gibelliana on, in Spain,
405.

—, Sphaerium wolffensteiniani on, in Spain,
405.

—, study of fungi attacking, in Porto
Rico and Virgin Islands, 562.

—, Trametes obstinatus on, in 8. Africa,
142.

—, ‘witches’ broom’ on, in Italy, 404,

Citrus aurantium, see Orange.

— aurantifolia, see Lime.

— decumana, see Grapefruit.

— limonum, see Lemon,

— medica, see Lime.

— nobilis, see Orange.

— sinensis, see Orange.

Cladosporium on cucumber in California,
152.

— on ginseng in Korea, 503.

— on Setaria italica in Ceylon, 7.

— on timber in U.S.A., 185.

— aphidis for control of plant lice and
Phylloxera, 413.

— carpophilum on peach in California,
127; in Connecticut, 220 ; in Illinois,
454; in New Jersey, 506; varietal
resistance to, in California, 127.

— citri in relation to citrus scab, 366.

— cucumerinum on Cucurbitaceae in
Denmark, 488.

— — on cucumber in Germany, 201;
in Norway, 203.

— — on melon, in Norway, 203.

— —on watermelon in U.S.A., 280.

— fuleum on tomato, 245; control by
solbar in Germany, 132, 529; occur-
rence in Denmark, 246, 488 ; in Eng-
land, 347; in Germany, 182, 529; in
Norway, 203 ; in Trinidad, 335.

— fumago on citrus in Spain, 405.

— graminum, variation in conidia of, 391.

— herbarum on citrus in Spain, 405.

— — on peach in Holland, 94.

— — on wheat in Uganda, 264.

— laricis f. pini-pineae on stone pine in
Italy, 297.

-— stage of Ceratostomella piceae, 50.

Claviceps, dissemination of sclerotia of,
115.

— purpurea on rye, artificial cultivation
of, in Austria, 114, 400; biology of
sclerotia of, 116; control in N. Da-
kota, 498.

— — on rye x Secale montana hybrids,
artificial cultivation of, in Austria,
400.

— —on rye x wheat hybrids in France,
363.

— — on wheat in France, 115, 160.

— — f. natans Phalaris arundinaceae on
Phalaris arundinacea, 116.

— wilsoni on Glyceria fluitans, biology of
sclerotia of, 115.

Clonostachys on timber in U.S.A., 185.

Clove (Eugenia caryophyllata\, Cephaleuros
mycoidea on, in Malaya, 426.

—, diseases of, in Zanzibar, 355.

Clover (Trifolium), dry spot disease of, in
Norway, 202.

—, Erysiphe polygoni on, in Canada, 504.

—, Gibberella saubinetii on, in Holland,
53.

—, leaf curl of, in Italy, 325.

— mosaic, effect of temperature on, 77 ;
protozoa in relation to, 227, 514, 515 ;
occurrence in Arkansas, 441.

—, Peronospora trifoliorum on, in Morocco,
54,

—, Phyllachora trifclii on, renamed Piow-
rightia trifolii, 546.

—, Polythrincium trifolii on, in France,
544; perfect stage of, 546.

—, Rhizoctonia violacea on beet following.
in Czecho-Slovakia, 467.

—, — — on, in England, 450.

—, Sclerotinia trifoliorum on, in British

N 3

610

Columbia, 395; in England, 450;
varietal resistance to, 512.

[Clover], Sphaerulina trifolii on, in U.S.A.,
414,

—, Typhula trifolii on, in Norway, 202.

— (Egyptian) (Trifolium aexandrinum),
see berseem.

Coal gas, toxic action of, on plants, 331.

Coccomyces hiemalis on cherry, control in
Canada, 258; in Illinois, 454; in
Michigan, 73; in New York, 546; in
Wisconsin, 492.

Cochlearia armoracia, see Horse-radish.

Cockchafer, Isaria densa on, in France,
412.

Cocoe (Xanthosoma sagittifolium), rot of,
in Jamaica, 103.

—, Vasculomyces xanthosomae on, in Ja-
maica, 103.

Coco-nut (Cocos nucifera), Aphelenchus coco-
philus on, in British Guiana, 355;
probably in Cuba, 268.

—, Bacillus coli not believed to cause bud
rot of, in Cuba, 268.

— bleeding disease in Malaya,
(See also Thielaviopsis paradoxa).
— bud rot in British Guiana, 355; in
Ceylon, 7; in Cuba, 268; in Malaya,
396 ; in Fiji, 215,311; in Guadeloupe,
33; in Jamaica, 184; in the Philip-
pines, 109; in Surinam, 107; in

Trinidad, 394,

—, Fomes applanatus, F. multiplicatus, and
F. ochrolaccatus on, in St. Thomas Is-
land, 589.

— leaf disease in Dutch E. Indies, 9.

—, legislation against diseases of, in
Malaya, 238 ; in Tanganyika, 192.

—, ‘nut-fall’ of, in Ceylon, 543; in
Malaya, 396.

—, Oryctes rhinoceros not believed to
cause bud rot of, in Cuba, 268.

—, Pestalozzia on, in Ceylon, 7; in Dutch
E. Indies, 9.

—, — palmarum on, in Ceylon, 527 ; in
the Philippines, 109.

—, Phytophthora causing nut-fall of, in
Ceylon, 7; probable cause of bud rot
of, in Fiji, 215.

—, — faberi on, in Cuba, 268,

—, — palmivora on, in Jamaica, 184,
268.

—, Polystictus occidentalis and P. sanguineus
on, in St. Thomas Island, 589.

—, Thielaviopsis paradoxa on, in Florida,
23; in Guadeloupe, 33; in Madras,
79; in the Philippines, 109.

—. Trametes ohiensis on, in St. Thomas
Island, 589.

Cocos nucifera, see Coco-nut.

Coffea, see Coffee.

Coffee (Coffea), Armillaria mellea on, in
Uganda, 409.

— berry borer destroyed by Botrytis
stephanoderis and Spicaria javanica in
Dutch E. Indies. 368.

—, Capnodium brasiliense on, in Uganda,
408.

—. Cercospora coffeicola on, in Uganda,
156, 408.

396.

GENERAL INDEX

[Coffee], Colletotrichum coffeanum on, in
Uganda, 156, 408, 409.

—, — incarnatum on, in Ceylon, 7..

—, Corticium koleroga on, in India, 448.

—, — salmonicolor on, in Duteh E.
Indies, 9.

—, die-back of, in Ceylon, 7; in Uganda,
156, 408.

—, Fomes lamaoensis on, in Dutch E.
Indies, 9; in Uganda, 409.

—, Glomerella cingulata on, in Uganda,
408.

—, Hemileia vastatric on, in Ceylon, 7,
585, in India, 448; in Uganda, 155,
156, 408; spraying tests against, in
India, 448 ; teleutospores of, in Ceylon,
585 ; varietal resistance to, in Uganda,
155.

—, Hypochnus on, in Dutch E. Indies, 9.

—, legislation against importation of,
in India, 240.

—, mottling of leaves of Robusta, in
Dutch E, Indies, 9.

—, Phoma on, in Uganda, 408.

—, Polyporus coffeae on, in Uganda, 156,
409.

—, Septobasidium borgoriense on, in Java,
145.

—. spraying against leaf diseases of, in
India, 448.

—, study of fungi attacking, in Porto
Rico and Virgin Islands, 562.

—, Trachysphaera fructigena on, in the
Gold Coast, 495.

—, Ustxlina zonata on, in Kenya, 260.

—, ‘witches’ broom’ of, in Uganda, 409,

Coix lacryma-jobi, Helminthosporium oryzae
on, in Japan, 281.

Coleosporium on aster in U.S.A., 349.

— ipomoeae, host plants of, in U.S.A.,
348.

— ribicola, host plants of, in U.S.A,,
348.

— solidaginis, host plants of, in U.S.A.,
349.

Coleus, stimulating effect of Bordeaux
mixture on, 508.

‘Collar crack’ of cacao in Togoland,
210.

Colletotrichum on fig in Uganda, 157.

— agaves on maguey in the Philippines,
109.

— — on sisal in the Philippines, 108.

— — on zapupe in the Philippines,
108.

— atramentarium on potato in Pennsyl-
vania, 390.

— cereale, cereal seed treatment against,
in N. Dakota, 498.

— circinans on onions, cause of varietal
resistance to, 492; occurrence in S.
Australia, 292.

— coffeanum on coffee in Uganda, 156,
408.

— falcatum on sugar-cane in Australia,
580; in Barbados, 261 ; in Cuba, 525;
in Java, 8; in the Philippines, 109.

— gloeosporioides on citrus in Spain,
405.

| — — on limes in Trinidad, 394.

GENERAL INDEX

[Colletotrichum gloeosporioides] on grapefruit
in the Philippines, 108.

— — on mandarin orange in N. S.
Wales, 354.

— — on oranges in the Philippines,
108.

— gossypii on cotton, seed disinfection
by heat against, 500.

— —, toxicity of sulphur to, 460.

uae on sorghum in Uganda,

— incarnatum on coffee in Ceylon, 7.

— lagenarium can infect cantaloupe,

citron, cucumber, gourds, and
squashes, 256.
— — on watermelon in Texas, 256;

in U.S.A., 280.

— lindemuthianum, nutrition of host in
relation to attack by, 162.

— — on beans, effect of uspulun on,
20; occurrence in Bermuda, 306;
in Trinidad, 3535. (See also Glomerella
lindemuthianum).

— —, promotion of sporing in, by lactic
acid, 24.

— lini on flax in Germany, 118; in
Michigan, 313.

— linicolum on flax in Ireland, 116;
identical with C. Jini, 118, 313.

— oligochaetum on cucumber in England,
250.

— — on cucurbits in Astrakhan, 207.

— omnivorum (?) on sugar-beet in Korea,
524.

— panicicolau on ginseng in Korea, 502,

— phomoides on tomato, 245.

— trifolii on lucerne in Arkansas, 441;
in S. Africa, 110.

Collybia velutipes on red currant in Hol-
land, 53.

Commelina benghalensis, Kordyana celebensis
on, 341,

Commelinaceae, species of Brachybusidium
and Kordyana on, 341.

Coniothecium chomatosporum on apple and
pear in Queensland, 122; inS. Africa,
271; in S. Australia, 292.

— scabrum on orange in §S. Australia,
292.

Coniothyrium on red currant in Holland,
53.

— caryogenum, pecan kernel spot not due
to, in U.S.A., 283.

— diplodiella on vine, control and distri-
bution of, 45; occurrence in Ontario,
436 ; in Switzerland, 302.

— fuckelii on raspberry in Germany,
201; in Holland, 53.

Convoloulus, Coleosporium ipomoeae on, in
U.S.A., 348.

Copper acetates as fungicides, 18.

— compounds as preventatives of bunt
in wheat in Italy, 322.

— —, influence of treatment with, on
the production of wheat, 322.

— dust treatment against Tilletia tritici
on wheat in Canada, 253, 459; in
Italy, 322; in U.S.A., 74, 264, 458,

— lime dusts as fungicides in Canada,
253, 459, 549; in U.S.A., 204, 264.

611

[Copper] sprays, influence on potato
tubers of, in U.S.A., 522.

— sulphate not injurious to animals fed
on grain treated with it, 512.

Corchorus, see Jute.

Cordyceps militaris on larvae of insects in
Sweden, 76.

Coronilla, Cercospora rautensis on, 342.
Corticium, brown root disease of rubber
caused by a fungus resembling, 291.
— on Calophyllum burmanni, Erythroxylon
coca, Hemidesmus indicus, Oxyanthus tubi-

florus, and tea in Ceylon, 473.

— javanicum, see C. salmonicolor.

— koleroga on coffee in India, 448.

— salmonicolor on apples and pears in
Mauritius, 203.

— —on Casuarina equisetifolia in Mauri-
tius, 203.

— — oncinchonain Dutch E. Indies, 9.

— — on citrus in the Philippines, 108.

— — on coffee in Dutch E. Indies, 9.

— —on rubber in Dutch E. Indies, 8;
in Malaya, 396.

— — on tea in Java and Sumatra, 9.

— —, Septobasidium bogoriense predisposes
to attacks of, 145.

— solani on beet in Denmark, 487; in
Korea, 524.

— — on Stilaria in Denmark, 563.

— — on ginseng in Korea, 503.

— —on pine seedlings in U.S.A, 5.

— — on potato, effect of, 85; occur-
rence in Canada, 26.

— —, relations between, and [hizoctonia
solani, 471.

— —, see also Rhizoctonia solant.

— vagum, see C. solani.

Corynespora melonis on cucumber in Ger-
many, 201.

Cosmos, Fusarium udum on, in Uganda,
163.

—, Phomopsis stewarti on, in U.S.A., 261.

Cotton (Gossypium), Ascochyta gossypii on,
in Arkansas, 215, 441.

—, Bacterium malvacearum on, in Arizona,
154; in the Philippines, 445; in
U.S.A., 217; seed disinfection against,
154, 217.

—, bacterial boll rot of, in S. India,
367.

—, Colletotrichum gossypii on, seed dis-
infection by heat against, 500.

—, Fusarium vasinfectum on, control by
potash fertilizers in U.S.A., 66 ; occur-
rence in Arizona, 154; in Arkansas,
441.

—, legislation against importation of, in
India, 240.

—, Ozonium omnivorum on, see Phymato-
trichum omnivorum.

—, Phymatotrichum omnivorum on, in Ari-
zona, 154, 501; in U.S.A., 441.

—, Phytophthora palmivora in boll rot of,
in W. Indies, 185.

—, raw and textile, effect of bacteria
and fungi on, 544,

—, Rhizoctonia solani on, in Arizona, 154.

—, Rhizopus nigricans causing boll rot of,
in Egypt, 449.

612

[Cotton], seed disinfection with uspulun
increases yields of, in Mexico, 509.
—, Verticillium albo-atrum can infect, 150.

— wilt, see Fusarium vasinfectum.

Cowpea (Vigna), Alternaria atrans on, in
Arizona, 250.

—, Bacterium vignae on, in Indiana, 485.

—, leaf curl of, in Dutch E. Indies, 10.

— mosaic in Arkansas, 441.

—, sunburn injury to, in Arizona, 249.

Crataegus, eradication ot, for control of
Bacillus amylovorus in New Zealand,
273.

— oxyacantha, Bacillus amylovorus on, 162.

— pyracantha, Bacillus amylovorus on, 163.

Crayfish, Aphanomyces magnusi causing
disease of, in Germany, 410.

Crepis aurea, Protomyces crepidicola on, 242.

— biennis, Protomyces crepidicola on, 242,
243.

— paludosa, Protomyces crepidis-paludosae
on, 243.

— pontana, Protomyces crepidicola on, 242.

Cricula_ trifenestratu, Botrytis stephanoderis
parasitic on, in Dutch E. Indies, 369.

Crinkle joint disease of wheat in Canada,
304.

Crithidia, action of latex of plants on, 523.

Crocus sativus, see Saffron.

Cronartium conigenum on chestnut and
oak in N. America, 3.

— —on pine cones in N. America, 3.

— ribicola, account of disease of pines
and Ribes caused by, 3.

— —, factors influencing spore germi-
nation, 516,

— — introduction into U.S.A., and
losses caused by, 143.

— —, legislation against, in British
Columbia, 253, 395; in Canada, 107;
in U.S.A., 4; in Washington, 483;
in Western U.S.A., 4.

— — on currants in Canada, 304; in
Switzerland, 483; in U.S.A.,4, 107, 205.
— — on gooseberry in Switzerland,

483 ; in U.S.A., 4, 107, 205.

— —on pine in British Columbia, 253,
395 ; in Europe, 49 ; control in U.S.A.,
4, 107, 205; in Western U.S.A., 4.

— — on Pinus strobus in U.S.A., 205.

— —, susceptibility of species of Ribes
to, 205, 483.

— —, viability of teleutospores of, 4.

— strobilinum on chestnut and oak in N.
America, 3.

— —on pines in N. America, 3.

Crown or ‘juvenile’ disease of oil palm
in Dutch E. Indies, 9.

— gall, see Bacterium tumefaciens.

Cruciferae, susceptibility of different, to
Plasmodiophora brassicae, 432.

—, Phoma napobrassicae on, in Denmark,
487.

—, Pseudomonas. campestris on, in Ber-
muda, 306.

Cryptosporella viticola on vine in France,
532.

Cucumber (Cucumis sativus), Alternaria on,
following sun scald, in California, 152.

—, bacterial disease of, in Germany, 201.

GENERAL INDEX

[Cucumber], Bacterium lacrymans on, ac-
count of, 196; dissemination and
control of, in California, 152.

—, Cercospora melonis on, in Denmark,
488.

—, Cladosporium on, following sun scald
in California, 152.

—, — cucumerinum on, in Germany, 201 ;
in Norway, 203.

—, Colletotrichum lagenarium can infect,
256.

—, — oligochaetum on, in England, 250.

—, Corynespora melonis on, in Germany,
201.

—, Diplodina lycopersici on, in England,
208.

— diseases controlled by ‘solbar’ in
Germany, 132.

—, LErysiphe cichoracearum on, in Cali-
fornia, 152.

—, Fusarium on, in California, 152.

— mildew, ‘Pri’ sulphur against, in
Germany, 171.

— mosaic, control in California, ‘152;
hosts of, 512 ; intracellular bodies in
relation to,514 ; occurrence in England,
489 ; probably transmitted by seed in
England, 491 ; transmitted by aphids,
513; transmitted from Asclepias in
U.S.A., 107 ; transmitted to Amaran-
thus retroflecus, 513; to Asclepias syriaca,
512; to Physalis, 513; to Phytolacca
decandra, 512 ; two types of, in Britain,
491.

—, Oidium on, in Astrakhan, 207.

—, Orobanche aegyptica on, in Astrakhan,
207.

—, Pseudoperonospora cubensis on, in Ger-
many, 201; in Massachusetts, 440.

—, Sclerotinia on, in California, 152.

—, Verticilliwm albo-atrum can infect, in
England, 150.

Cucumis sativus, see Cucumber.

— melo, see Cantaloupe and Melon.

Curcurbita mosaic disease in Sumatra, 35.
(See also Squash),

— pepo, see Marrow.

Cucurbitaceae, Cladosporium cucumerinum
and Macrosporium melophthorum on, in
Denmark, 488.

Cucurbits, Coiletotrichum oligochaetum on,
in Astrakhan, 207.

—, mosaic, hosts of, 512.

Cupressus, see Cypress.

Cuprosolfol against vine diseases in
Italy, 326.

Curly needle disease of Pinus muricata
and P. insignis in N.S. Wales, 299,
354; in S. Australia, 298.

Currants (Ribes), Coleosporium ribicola on,
in U.S.A., 348.

—, Collybia velutipes on, in Holland, 53.

—, Coniothyrium on, in Holland, 53.

—, Cronartium ribicola on, in Canada,
304 ; in Switzerland, 483; in U.S.A.,
4, 107, 205.

—, leaf edge disease of, in Denmark,
488.

—, mildew of, ‘ Pri’ sulphur against, in
Germany, 171.

GENERAL INDEX 613

(Currants], Mycosphaerella grossulariae on,
control in Illinois, 454,

—, Polyporus ribis on, in Germany, 201.

—, Pseudopeziza ribis on, in Switzerland,
277.

—, Sphaerotheca mors-uvae on, in Italy,
277.

Curtisea faginea, Fomes connatus and F.
rimosus on, in 8. Africa, 142.

Cutworms, Entomophthora megasperma on,
in Natal, 412.

Cyclamen persicum, Gloeosporium attacking,
in Germany, 269.

Cycloconium oleaginum on
Morocco, 54.

Cydonia sinensis, Gymnosporangium asiati-
cum on, in Japan, 237.

— vulgaris, see Quince.

Cylindrosporium padi on cherry in N.S.
Wales, 354; in U.S.A., 110.

Cymatophora duplaris and C. flavicornis,
Cordyceps militaris on larvae of, in
Sweden, 76.

Cynodon dactylon, Helminthosporium oryzae
on, in Japan, 231.

Cynometra cauliflora, Phytophthora differing
from P. meadii on, in Ceylon, 7.

Cyphomandra betacea, Alternaria solani on,
in Dutch E., Indies, 422.

Cypress (Cupressus), ‘ witches’ broom’ on,
in Italy, 404.

Cystopus candidus, biological strains of,
563.

— —on cabbage in Denmark, relation
of weeds to, 563.

Cystospora batata on sweet potato in New
Jersey, 31.

Cytospora, British species of, 391.

— chrysosperma on Acer saccharinum in
Canada, 96.

— — on poplar in Canada, 96; in
U,S.A., 96, 205.

— prunorum on peach in Holland, 94.

— sacchari on sugar-cane in Argentina,
339.

Cytosporina on elm in Holland, 2.

— citriperda on mandarin orange in
Italy, 310.

olives in

Dactylis glomerata, biology of Claviceps
sclerotia on, 116.

Dahlia, Entyloma (?) calendula on, in
Holland, 54.

‘Dartrose’, see Vermicularia varians.

Date palm (Phoenix dactylifera), Alternarta
on, in Arizona, 154.

— —, baioud or white disease of, in
Algeria, 328.

— —, Helminthosporium on, in Arizona,
154,

— —, Macrosporium on, in Arizona, 154.

— —, n’faroun disease of, in Algeria,
328.

Datura, Alternaria solani on, in Dutch E.
Indies, 422.

— stramonium, tomato mosaic not trans-
missible to, in Indiana, 40,

Daucus carota, see Carrot.

Delphinium, Fusarium

Uganda, 163.

udum on, in

Dematium on elms in Holland, 2.
— monophyllum on citrus in Spain, 405.

'— puillulans (?) on elms in Holland, 2.

‘Dendrin’, use of, against apple mildew
in Germany, 223.

Dendrophoma cinchonae on cinchona in
Indo-China, 96.

Dendrostilbella boydii a conidial stage of
Allescheria boydii, 227.

Dewberry (Rubus caesius), mosaic of, in
New York, 352.

Dianthus, see Carnation.

Diaporthe perniciosa on plums in England,
209.

Didymella applanata on raspberry in Den-
mark, 488; in Germany, 128, 201,
457 ; in Switzerland, 278, 302.

— lycopersici on tomato in Denmark,
488.

Didymopsis omnivora, mycorrhizal fungus
resembling, in Italy, 283.

Dielsiella identical with Cycloschizon, 141.

Diplodia causing gummosis of citrus in
Argentina, 62; in California, 5438.

—, gumming caused by inoculation of
orange and lemon with, in California,
541,

— on maize and Pennisetum typhoideum in
India, 259.

— on rubber in Malaya, 396.

— cacaoicola, see Botryodiplodia theobromae.

— citricola on orange in S. Australia,
292.

— lycopersici on chilli in Holland, 54.

— natalensis on grapefruit from W. Indies,
65.

— theobromae, see Botryodiplodia theobromae.

— tubericola on potatoes from Java, 423,

— —on sweet potato in Texas, 256.

— — on watermelon in U.S.A., 256,
280,

— zeae on maize in U.S.A., 56, 106, 218,
257, 442, 446; varietal resistance to,
in Indiana, 56.

Diplodina lycopersici on
Britain, 208.

— —on tomato in Denmark, 246.

Dipodium punctatum, mycorrhiza of, in
N. S. Wales, 78.

Discella carbonacea on Salix alba in Holland,
94,

Distichlis spicata, spread of Puccinia sub-
nitens from, to spinach in U.S.A., 101.

Doona zeylanica, Poria, hypolateritia on, in
Ceylon, 295.

Dothichiza, similarity of, to Phomopsis, 51.

— populea on poplar in Canada, 96.

Douglas fir, see Pseudotsuga taxifolia,

Dry-mix sulphur lime, formula for, 506,

Dryopteris linnaeana and MD. _ robertiana,
Hyalopsora poiypodii-dryopteridis on, 586.

Dry rot of potato in Dutch E. Indies, 8,
423.

Dusts, use of, against fruit diseases, 71,
219, 492, 506; oat smut, 459, 549 ;
tomato late blight, 346 ; vine diseases,
858; wheat smuts, 73, 206, 253, 264,
322, 400, 458, 459.

cucumber, in

Earthnut, see Groundnut.

614 GENERAL INDEX

Earthworms as disseminators of Plasmo-
diophora brassicae, 351.

Echinobotryum citri on citrus in Spain,
405.

Echinochloa crus-galli a host of sugar-cane
mosaic, 584.

Echinodontium tinctorium on logs of fir and
hemlock in U.S.A., 531.

Eggplant (Solanum melongena), Sicha
solanion, in Dutch E. Indies, 422

—, Bacterium solanacearum on, a the
Philippines, 261, 262, 445.

—, mosaic-like disease of, in Astrakhan,
535.

—, Orobanche aegyptiaca on,in Astrakhan,
207.

—, Verticillium albo-atrum can infect, in
England, 150; occurs on, in U.S.A.,
110.

Egyptian clover, see Berseem.

Elaeis guineensis, see Oil palm.

Elaeodendron croceum, Fomes rimosus on, in
S. Africa, 142.

Elderberry (Sambucus nigra), Gloeosporium
Fructigenum var. sambuci on, in Switzer-
land, 299.

Eleusine coracana, Piricularia on, in India,
259.

— —, Phyllachora eleusines on, in Uganda,
264.

— —, Ustilago eleusinis on, in India, 308.

— indica, Helmtnthosporium oryzae on, in
Japan, 231.

— —, mosaic disease of, in Hawaii, 241.

Elm (Ulmus), bacteria on, in Holland, 2.

—, Botrytis on, in Holland, 2.

—, Cephalosporium on, in Holland, 2.

—, Cytosporina on, in Holland, 2.

—, Dematium on, in Holland, 2.

—, — pullulans (?) on, in Holland, 2.

—, die-back of, in Germany, 201.

—, Fusarium on, in Holland, 2, 93.

—, Graphium on, in Holland, 2.

—, — ulmi causing disease of, in Holland,
93 ; evidence not accepted, 431,

—, Monilia on, in Holland, 2.

—, obseure disease of, in Holland and
neighbouring countries, 1, 93, 431,
484 ; attributed to Graphium ulmi, 93;
to Scolytus beetles, 484; varietal sus-
ceptibility to. 1, 93.

—, Phoma on, in Holland, 2.

—, Ramularia on, in Holland, 2.

— Sphaeropsis ulmicola on, in Wisconsin,
481.

—, Verticillium albo-atrum-can infect in
Britain, 150.

‘ Elosal’, control of apple mildew with,
in Germany, 121 ; of vine Oidium with,
in Germany, 255.

Elymus, Puccinia glumarum on, in Cali-
fornia, 392.

Empusa aulicae, control of brown-tail
moth by, in U.S.A., 312.

— fresenii parasitic on aphids, 311.

— grylli parasitic on grasshoppers in
Natal, 412.

— lageniformis parasitic on aphids, 311.

— lecanii parasitic on Coccus viridis in
Java, 311.

F Endomyces vernalis, growth inhibited by

Spicaria purpurogenes, 567.

Endothia parasitica on chestnut, danger of
introducing into Europe, 189; intro-
duction into U.S.A., 148; losses
caused by, 143; occurrence in China
and Japan, 189; in U.S.A., 107, 143,
191, 481; varietal resistance to, 107,
481.

Entomogenous fungi in Ceylon, 370 ; in
Dutch E. Indies, 368 ; in France, 313 ;
in 8. Africa, 70, 412; in U.S.A., 312,
369.

Entomopeziza soraueri, see Fabraea macu-
lata.

Entomophthora fumosa parasitic on Pseudo-
coccus cityi in Florida, 312.

— megasperma parasitic on cutworms in
Natal, 412.

Entomosporium on loquats in S, Africa,
70.

— maculatum, see Fabraea maculata.

Entyloma (?) calendula on dahlia in Hol-
land, 54.

Epichloe sasae on Sasa spiculosa in Japan,
238.

Epicoccum hyalopes on rice in Uganda,
157

Epitrix cuéumeris probably transmits
tomato mosaic in Indiana, 40.

Ergot, see Claviceps purpurea.

Ericaceae, tubers at base of, 136.

Erica arborea, Torula ligniperda on, in
Europe, 34.

Eriosbotrya japonica, see Loquat.

Erwinia phytophtiora, see Bacillus atrosep-
ticus.

Erysiphaceae, papaw attacked by one of
the, in Bermuda, 306.

Erysiphe on cabbage in Trinidad, 335.

— cichoracearum, biological specialization
of, 180.

— — on cucumber, control in Cali-
fornia, 152.

— graminis on barley, 487.

— — on cereals in Germany, 162; in
Morocco, 54.

— — on oats in Wales, 401.

— — on’ wheat in Denmark, 487; in-
creases acidity of infected plants, 361.

— horridula, biological specialization of,
on Boraginaceae, 180.

— polygoni, genetics of resistance to, in
Oenothera, in U.S.A., 74.

— — on beans, control in Germany,
171; occurrence in Bermuda, 306.

— — on clover in Canada, 304.

Erythrina, Septobasidium bogoriense on, in
Dutch E. Indies, 145.

Erythroxylon coca, Corticium on, in Ceylon,
473.

Esca disease of vine, see Apoplexy of
vine.

Ethylene, toxic action of, on plants,
332.

Eucalyptus, tumours formed in, 135.

— globulus, Ganoderma sessile on, in
Argentina, 17.

Euclea macrophylla, Palawaniella eucleae on,
in 8. Africa, 141.

a OS

GENERAL INDEX 615

[Euclea] natalensis, Isipinga areolata on, in
S. Africa, 141.

Eugenia caryophyllata, see Clove.

—_ ee Fusarium udum on, in Uganda,

63.

Euphorbia, protozoa in latex of, 54, 176,
177, 229, 424, 523.

— arkansana, Uromyces dictosperma on, in
U.S.A., 472, 4738.

— dentata and E. presiii,
eminens on, in U.S.A., 472.

Excoecaria emarginata, protozoa in latex
of, 229.

Exoascus deformans on almond, apricot,
Becune, and peach in New Zealand,
373.

— — on peach, control in Germany,
166; in New Zealand, 165, 373; in
U.S.A., 73, 374, 454, 506, 546 ; occur-
rence in Astrakhan, 535.

— minor on cherry in New Zealand,
373.

— — on Prunus chamaecerasus in Ger-
many, 373.

— pruni on plum in Canada, 255; in
New Zealand, 373; in U.S.A., 439.
Exosporium preisii on Phoeniz in Denmark,

4

Fromyces pro-

Fabraea maculata on pear in New Jersey,
110; in S. Africa, 71.

— — on quince in S. Africa, 71; in
Switzerland, 275, 302.

Fagus sylvatica, see Beech.

Fasciation produced by Bacterium tume-
faciens, 10.

Festuca elatior, Puccinia lolii on, in U.S.A.,
209.

Ficus carica, see Fig.

— elastica, crown gall formation in, 494.

Fig (Ficus carica), amoebae in latex of,
177; harmless to cats, 230.

—, Aspergillus niger on green and dried,
in California, 130.

—, Colletotrichum on, in Uganda, 157.

—, die-back of, in France, 188.

—, Ganoderma sessile on, in Argentina,
17.

—, Kuehneola fici on, in Uganda, 157.

Fiji disease of sugar-cane caused by
Phytamoeba sacchari, 235; in Australia
and Fiji, 578; in N. S. Wales, 354;
in the Philippines, 88, 109, 234; risk
of introduction to western hemi-
sphere, 469.

Filao, see Casuarina equisetifolia.

Fir (Abies), Fomes annosus on, in Saxony,
482.

—, Torula ligniperda on, in Europe, 34.

—, see also Abies.

Fireblight, see Bacillus amylovorus,

Flax (Linum usitatissimum), Botrytis cinerea
on, in Holland, £3.

—, Colletotrichum lini on, in Germany,
118; in Michigan, 313.

—, — linicolum on, in Ireland, 116;
stated to be identical with C. lini, 118,
313.

— droop in Ireland, 117.

[Flax], Fusarium lini on, in Canada, 304 ;
in Kenya, 260; temperature relations
of, in U.S.A., 67.

—, Gloeosporium lini on, see Colletotrichum
lini.

— heat canker in U.S.A., 313.

—, Melampsora lini on, in Canada, 304;
in Ireland, 117; in Morocco, 54;
specialized races of, 117.

—, Polyspora lini on, in Ireland, 116.

—, Sclerotinia libertiana on, in Ireland,
118.

— seed disinfection, 116.

—, Thielavia basicola on, in Ireland, 117.

— wilt, see Fusarium lini.

‘Flick’ spraying apparatus against vine
diseases in Austria, 532.

Fomes on Hevea rubber in Dutch E.
Indies, 8.

— annosus, forest rejuvenation for con-
trol of, in Germany, 430.

— — on fir trees in Saxony, 482.

— —on pines in Holland, 430.

— —on stumps of fir, larch, and pine
in U.S.A., 531.

— — tissue decay caused by, 98.

— annularis on Olea laurifoliain S. Africa,
142.

— applanatus on Acacia in Ceylon, 295.

— — on coco-nut in St. Thomas Island,
589.

— — on oil palm in St. Thomas Island,
589.

— — on Olea laurifolia in S. Africa, 142.

— —on tea in Ceylon, 295.

— australis on Olea laurifolia in 8. Africa,
142,

— conchatus on Melia azedarach in S.
Africa, 142.

— connatus on Curtisea faginea in S, Africa,
142.

— cryptarum, oak timber decayed by, in
Versailles Palace, 97.

— demidoffii on Juniperus procera in
Kenya, 529.

— fomentarius, ash analysis of, 284.

— — on poplar in France, 198.

— geotropus on Ocotea bullata, Podocarpus,
and Virgilia capensis in S. Africa, 142.
— igniarius, ash analysis of, 284 ; effects

of, on oak, 284,

— —on aspen in Utah, 97.

— —on vine in France, 326, 437, 528.

— juniperinus on junipers in U.S.A.,
530.

— — on Juniperus procera in Kenya,
529.

— lamaoensis on coffee in Duteh E.
Indies, 9 ; in Uganda, 409.

— — on Hevea rubber in Ceylon, 7,
291.

— — on tea in Ceylon, 291; in India,
343.

— laricis on Douglas fir in U.S.A., 205.

— — on stumps of fir, larch, and Pinus
ponderosa in U.S.A., 531.

— leucophaeus on Olea laurifolia in S
Africa, 142.

— lignosus in Uganda, 156.

| —— on Hevea rubber in Ceylon, 7,

616

374; in Malaya, 396; toxicity of lime
to, 374.

[Fomes] muiltiplicatus on coco-nut in St.
Thomas Island, 589.

— ochrolaccatus on coco-nut in St. Thomas
Island, 589.

— pectinatus on cacao in St. Thomas
Island, 589.

— pinicola on Pinus ponderosa in Oregon,
482.

— — on stumps of fir and larch in
U.S.A., 531.

— pseudoferreus on Hevea rubber in Dutch
E. Indies, 8; in Malaya, 396.

— rimosus on Acacia, Curtisea faginea,
Elaeodendron croceum, Kiggelaria africana,
Olea laurifolia, Pleurostyla, Ptaeroxylon
utile, and Rhus laevigata in S. Africa,
142.

— — on Robinia pseud-acacia in Michigan,
189.

— — on Schotia latifolia, Scolopia mundtii,
and Yymalos monospora in S. Africa,
142.

— roseus on Douglas fir in U.S.A., 205,
551.

— — on structural timber in U.S.A.,
146.

— — temperature relations of, 147,
148.

— rifo-flavus in greenhouses, mines, &c.,
in France, 98.

— senec on oil palm in St. Thomas
Island, 589.

— — on Sizygium in S. Africa, 142.

— vegetus on Olea laurifolia in S, Africa,
142,

— yucatensison Olea and Trema bracteola
in 8. Africa, 142.

Formaldehyde, chemotherapeutical in-
dex of, 556.

— injury to seed grain, J60, 266.

—, physiological effects of, on wheat
seed, 266.

— seed treatment against cereal dis-
eases in Canada, 253, 256, 459; in
Czecho-Slovakia, 550; in Germany,
161, 399, 416, 511, 552, 560; in N. Da-
kota, 498; in Sweden, 19; in U.S.A.,
458, 549; in Wales, 400; against
Helminthosporium gramineum in Wis-
consin, 491; against wheat bunt in
Austria, 538; in Canada, 258, 254,
459; in England, 308; in Germany,
555; in U.S.A., 73, 206, 264, 458; in
Wales, 400.

— soil treatment against Fusariwm in
pine seedlings, 300; against onion
smut, 206, 460,

— tank for onion smut treatment, 460.

— treated seed not injurious to animals,
512.

Fragaria vesca, see Strawberry.

Fraxinus, see Ash.

Fruit, amount of poison remaining on
sprayed, 168.

— diseases in Astrakhan, 535; in Aus-
tralia, 353; in California, 393; in
Canada, 255, 304; in Denmark, 488;
in England, 209; in Germany, 201;

GENERAL INDEX

in Holland, 53; in Illinois, 453; in
Malta, 452; in Michigan, 71; in New
York, 351, 546 ; in Ohio, 442 ; in Pen-
sylvania, 444; in Switzerland, 302;
in Uganda, 157; in Wisconsin, 257,
492.

[Fruit], handling of, for market, 67.

— quarantine in U.S.A., 589.

— rotting fungi, effect of temperature
and CO, on, 24.

— trees, sudden death of, in Tyrol in
1922, 16.

Fuchsine as a colouring matter for dis-
infectants of Hevea rubber in Java,
323.

Fumago vagans on tomato, 245.

Fungi, list of new genera of, 534.

—, synthetic culture media for, 82, 83.

Fungicides, chemotherapeutical studies
of, 551-560.

—, regulations for sale of, in Queensland,
591.

—, testing of, in Germany, 169.

Fungolit against cereal smuts in Ger-
many, 399.

Fungus cultures, mite infestation of,
325.

— —, ‘staling’ of, 328.

Fusafine for disinfecting seed grain in
Germany, 161.

Fusariol against Urocystis occulta in Ger-
many, 170.

Fusarium cultures, ‘ staling’ in, 330.

— hyphae, apical growth of, 588.

— on barley in Denmark, 487.

— on cereals, apparatus for seed treat-
ment against, 224; occurrence in Ger-
many, 200; in Norway, 202; seed
sterilization with mercury salts
against, 552.

— on citrus in California, 540, 543,

— on cucumber in California, 152.

— on elm in Holland, 2, 93.

— on hops in England, 132.

— on maize in India, 259; in Indiana,
56. j

— on peas in Canada, 304; in New
Zealand, 482.

— on Pennisetum typhoideum in India,
259.

— on pine seedlings in U.S.A., 5.

— on potato in Bermuda, 306; in Cana-
da, 26; in Dutch E. Indies, 423; in
Manitoba, 424; in store in India, 335.

— on raspberry in Holland, 53.

— on roots of various plants in Italy,
283.

— on rye in Bavaria, 281, 509; in Hol-
land, 55.

— on spinach in U.S.A., 100.

— on sugar-cane in Barbados, 260,
467.

— on sugar-cane setts in Argentina,
339.

— on tomato in England, 347; in Mor-
oceo, 54; temperature relations of,
in U.S.A., 67, 136.

— on wheat, occurrence in Denmark,
487; in S. Africa, 536; tolerance to
acidity and alkalinity of, 12.

GENERAL INDEX

[Fusarium] stage of Nectria hematochroma
on citrus in Argentina, 62.

— wilt of tomato, relation of soil tem-
perature to, 67, 136.

— arthrosporicides on timber in U.S.A,
185.

— avenaceum on wheat, influence of CO,
and hydrogen-ion concentration on,
383.

— batatatis on sweet potato in New Jersey,
30.

— blasticola on pine seedlings in Sweden,
299,

— caeruleum on potato in Norway, 202.

— conglutinans on cabbage in Canada,
258; in Delaware, 301; in Texas, 256;
in Trinidad, 335, 486; temperature
relations of, 67; varietal resistance
to, 258, 301, 486.

— cubense on banana in Panama, 322;
in the Philippines, 108 ; in St. Lucia,
261; in the West Indies, 217; rela-
tion of, to Panama disease, 217, 322.

— culmorum on pine seedlings in Sweden,
300.

— — on wheat in Kenya, 260; in-
fluence of CO, and hydrogen-ion con-
centration on, 383.

— discolor sulphureum on potato in Mani-
toba, 424.

— erubescens on tomato, 245.

— eumartii on potato in Nebraska, 386 ;
in Pennsylvania, 443.

— euoxysporum on pine seedlings in
Sweden, 300.

— ferruginosum on tomato in Britain,
149.

— gemmiperda associated with disease of
pear buds in Holland, 53.

— herbarum on wheat, influence of CO,
and hydrogen-ion concentration on,
383.

— hordearum on barley in Morocco, 54,

— hyperoxysporum on sweet potato in
New Jersey, 30.

— limonis on citrus in Spain, 405.

— lini, influence of soil temperature on,
67.

— — on flax in Canada, 304; in Kenya,
260.

— lycopersici on tomato, 245; in Arkan-
sas, 440; in England, 148, 347; in
Indiana, 10, 40; in Mississippi, 441;
in Missouri, 347; in Texas, 256; in
U.S.A., 40,428; relation of hydrogen-
ion concentration and soil moisture to,
477; temperature relations of, 428 ;
transmitted by seed, 92; varietal re-
sistance to, 40, 441.

— macroxysporum on pine seedlings in
Sweden, 299.

— malli on onions in Bermuda, 306; in
Ontario, 436.

— metachroum on pine seedlings in
Sweden, 299.

— minimum, see F. nivale.

— moniliforme on maize in Missouri,
213 ; in Pennsylvania, 442; in U.S.A,
106 ; in Wisconsin, 257.

— nivale on cereals in Norway, 202.

617

[Fusarium nivale] on rye in Germany,
control of, 161, 200, 417, 511.

—niveum on watermelon in U.S.A,,
280.

— orthoceras on tomato, 245.

— oxysporum, fungus resembling, on
rotted stored potatoes in Texas, 256.

— —, nutrient requirements of, 82.

— — on potato, control in Oregon,
206; factors affecting and methods
of infection of, 521 ; occurrence in Ber-
muda, 306; in Canada, 246, 332, 465 ;
in Manitoba, 424; in Nebraska, 386,
521 ; in Oregon, 206; in Pennsylvania,
443; in Texas, 256; temperature re-
lations of, 522.

— — on sweet potato in Mississippi,
441,

— — on tomato, 245; in Britain, 149.

— putrefaciens on apples in Switzerland,
302.

— radicicola, nutrient requirements of,

— redolens, fungus resembling, on pine
seedlings in Sweden, 299,

— roseum on rice in Uganda, 157.

— sclerotioides, fungus resembling, on
pine seedlings in Sweden, 300.

— — on tomato in Britain, 149.

— solani on melon, insect transmission
of, 561.

— —on pine seedlings in Sweden, 299.

— — on potato in Morocco, 54; rela-
tion of, to other organisms, 91.

— stages of Nectria coccinea and N. galli-
gena compared, 90.

— subcarneum on pine seedlings in
Sweden, 300.

— subulatum on pine seedlings in Sweden,
299.

— sulphureum on tomato, 245; in Den-
mark, 246.

— trichothecioides on potato in Nebraska,
386.

— udum on carnation and various other
plants in Uganda, 163.

— vasinfectum on cotton, control by
potash fertilizers in U.S.A. 66;
occurrence in Arizona, 154; in Ar-
kansas, 441,

— —on peas in Germany, 201.

— willkommii, apple and pear fruit
attacked by, in Denmark, 218.

— —characters of, as conidial stage of

fectria galligena, 90.

Fusicladium on fruit trees,
against, in Germany, 132.

— on loquat in S. Africa, 70.

— cerasi on cherry in Germany, 201.

— dentriticum, see Venturia inaequalis.

— effusum on pecan in Mississippi, 441.

— nirinum, see Venturia pirina.

— saliciperdum on Salix alba in Holland,
93.

Fusicoccum, fungus resembling, in rotted
pears in Holland, 53.

— on chestnut in California, 190.

— on Pinus insignis in 8. Australia, 298.

Fusoma parasiticum on hops in England,
132.

‘solbar’

N 4

618

Galanthus nivulis, see Snowdrop.

Ganoderma sessile on apricot, Casuarina
stricta, Eucalyptus globulus, fig, Gourliea
decorticans, pear, plum, pomegranate,
Robinia pseud-acacia, Tipuana tipa, and
various other forest and fruit trees in
Argentina, 17.

—, See also Fomes, Polyporus.

Garlic (Allium sativum), Macrosporium
parasiticum on, in Spain, 191.

—, Peronospora schleideni on, in Spain,
191.

—, Sclerotium cepivorum on, in Spain,
191.

Gas, toxic action of coal, on plants, 331.

Geranium, see Pelargonium.

Germisan, chemotherapeutical index of,
556.

— not injurious to animals, 512.

—, use of, against root rot of beet in
Germany, 224, 510; against cereal
diseases in Germany, 161, 162, 170,
281, 399, 416, 511, 550.

Gibberella saubinetii, influence of CO, and
hydrogen-ion concentration on, 383;
of hydrogen-ion concentration on, 308.

— — on barley in Holland, 53.

— — on clover in Holland, 53.

— — on maize in U.S.A., 106, 2138, 257,
442, 536; relation of soil moistureand
temperature to, in U.S.A., 257, 536.

— — on oats in Holland, 53.

— — on rice in Uganda, 157.

— — on rye in Holland, 53.

— — on wheat in Canada, 304 ; in Hol-
land, 53; in U.S.A., 257, 536; rela-
tion of soil moisture and temperature
to, in U.S.A., 257, 536.

Ginger (Zingiber officinale), Vermicularia
zingibereae on, in India, 249.

‘ Ginoechiatura’ of wheat in Italy, 561.

Ginseng (Panax quinquefolium), Alternaria
solani on, in Korea, 502.

—, Bacterium araliavorus on, in Korea,
502.

—, — panaxi on, in Korea, 502.

—, Cladosporium on, in Korea, 503.

—. Colletotrichum panacicola on, in Korea,
502.

—, Corticium solani on, in Korea, 503,

—, Mucor on, in Korea, 503.

—, Phoma panacicola on, in Korea, 503.

—, — panacis on, in Korea, 503.

—, Phyllosticia panax on, in Korea, 503.

—, Phytophthora cactorum on, in Korea,
503; in U.S.A., 433.

—, Sclerotinia on, in Korea, 503.

Gliocladium on timber in U.S.A., 185.

Gloeosporium on cyclamen in Germany,
269.

— on rose in N.S. Wales, 354,

— on rubber in Malaya, 140.

— on vine, in Arizona, 155.

— ampelophagum on vine in France, 5382 ;
in N. S. Wales, 487; in S. Africa,
353 ; in S. Australia, 353.

— fructigenum on vine in New Zealand,
534.

— — var. sambuci on elderberry in Swit-
zerland, 299.

GENERAL INDEX

[ Gloeosporium | limetticolum on limes in the
Philippines, 108.

-— lini on flax in Germany, believed to
be identical with Colletotrichum lini-
colum, 118.

— lunatum for control of Opuntia in
Australia, 397.

— malicorticis on apple in Queensland,
128.

— musarum on banana in the Philip-
pines, 279.

— pini stated to be identical with Lepto-
stroma pinastri, 342.

— psidii on guava and orange in Mexico,
414,

— ribis on gooseberry in S. Australia,
292.

— venetum on raspberry, occurrence and
control in U.S.A., 219, 258, 278, 454,
493.

— toxicity of sulphur to, 460.

Glomerelia on apple in storage, 123,

— cingulata on apple, occurrence and
control in U.S.A., 454, 505, 546.

— — on coffee in Uganda, 156, 408.

— — on tea in Assam, 344.

— — on vine in France, 532.

— — toxicity of sulphur to, 460.

— lindemuthianum on French and wax
beans in Denmark, 488.

— rufomaculans var. cyclaminis on cycla-
men in U.S.A., 270.

Glyceria fluitans, biology of Claviceps wilsoni
on, 115.

Glycine, see Soy-bean.

Gnomonia erythrostoma on cherry, attacked
by Trichothectum roseum in Switzerland,
277.

Gomphocarpus fruticosus, action of latex of,
on protozoa, 523.

Gooseberry (Ribes grossularia), Coleosporium
ribicola on, in U.S.A., 348.

—, Cronartium ribicola on, in Switzerland,
483 ; in U.S.A., 4, 107, 205; quarantine
regulations against, in U-S.A., 4.

—., Gloeosporium ribis on, in S. Australia,
292.

—, Phytophthora on, in Holland, 53.

—, — omnivora on, in Switzerland,
303.

—, Polyporus ribis on, in Germany, 201.

—, Pseudopeziza ribis on, in S. Australia,
353.

—. Sphaerotheca mors-urvae on, in Crimea,
69, 70 ; in Denmark, 563; in Germany,
132, 169, 171, 201, 223; in Holland,
53; in Italy, 277, 293; in Norway,
548 ; in Sweden, 457; in U.S.A., 454;
tests of control measures against, in
Crimea, 69, 172 ; in England, 376; in
Germany, 171, 228; in Holland, 53;
in Illinois, 454; in Norway, 548; in
Sweden, 457.

Gossypium, see Cotton.

Gourd, Colletotrichum lagenarium on, in
U.S.A., 256. (See also Cucurbita,
Lagenaria).

Gourliea decorticans, Ganoderma sessile on,
in Argentina, 17.

Grapefruit (Citrus decumana), Colletotrichum

.

ee

GENERAL INDEX

gloeosporioides on, in the Philippines,
108.

[Grapefruit], Diplodia natalensis on stored,
from W_ Indies, 65.

—~, Penicillium digitatum causes rise of
temperature in, 85.

—, Phomopsis caribaea on stored, from W.
Indies, 65.

—, — citri on, in U.S.A., 106.

—, Pseudomonas citri on, in Japan and
the Philippines, 64; in U.S.A., 106;
relation of age of tissues to infection
by, 64; susceptibility to, due to sto-
matal structure, 63.

— scab, use of Bordeaux oil emulsion
against, in Porto Rico, 539.

Grape vine, see Vine.

Graphiola phoenicis on Phoenix in Den-
mark, 488.

Graphium, absence of, in life-cycle of
_Sporotrichum carougeani, 21.

— on elm in Holland, 2.

— on timber in U.S.A., 185, 186.

— penicillioides (?) an imperfect stage of
Ceratostomella piceae, 50.

— stilboidewm on rice in Uganda, 157.

— ulmi on elm in Holland, 93, 481.

Grasshoppers, Empusa grylli on, in
Natal, 412.

Grass mosaic, see Maize and Sugar-cane
mosaic,

Green manure for control of Actinomyces
scabies on potato, 520.

Grevillea robusta, Fusarium udum on, in
Uganda, 163.

— — wet root rot fungus on, in Uganda,
157.

Grey speck disease of oats, 493 ; similar- *

ity to sugar-cane root rot, 526.

Grossularia, see Gooseberry.

Groundnut (Arachis hypogaea), Bacteriwm
solanacearum on, in Dutch E. Indies,
9, 351.

—, Cercospora personata on, in Dutch E,
Indies, 351.

—, cur] disease of, in Dutch E. Indies, 9.

—, Puccinia avachidis on, proposed legis-
lation to exclude from Africa, 351.

—, two obscure diseases of, in 8. Africa,
352. °

Guaiacum officinale, Phoma and Phomopsis
stewarti on, in Barbados, 261.

Guava (Psidium guajava), Gloeosporium
psidii on, in Mexico, 414.

Guignardia bidwellii, danger of mistaking
Coniothyrium diplodiella for, 45, 436.

— — on vine in France, 532.

— yersini on cinchona in Indo-China,

Gummosis of apricot and cherry, 120; of
citrus, 62, 64, 203, 539-43 ; of sugar-
cane, 8, 140, 354, 579.

Gymnosporangium, Japanese species of,
237.

— on apple and pear in Denmark, 563,

— asiaticum, hosts of, in Japan, 237.

— clavipes, factors influencing spore ger-
mination of, 516,

— globosum, structure of galls caused by,
378,

619

[Gymnosporangium] hemisphaericum, hosts
of, in Japan, 238.

— idetae, hosts of, in Japan, 238.

— juniperi-virginianae on apple in U.S.A.,
444, 546.

— —, structure of galls caused by, 378.

— sabinae on pear in Astrakhan, 535 ; in
Crimea, 172.

— shiraianum, hosts of, in Japan, 238.

— yamadae, hosts of, in Japan, 237.

Haplographium on timber in U.S.A.,
185, 186.

Hawthorn, see Crataegus.

Helianthus annuus, see Sunflower.

Helicobasidium mompa, Septobasidium bogo-
riense not identical with, 146.

Helminthosporium on barley in India, 259 ;
in Holland, 53.

— on cereals, apparatus for seed treat-
ment against, in Germany, 224.

— on dates in Arizona, 154.

— on millet in India, 259.

— on rice in India, 259; in U.S.A.,
334.

— on rubber in Malaya, 396.

— on Setaria italica in U.S.A., 61.

— ou sugar-cane in India, 259.

— on wheat in N. S. Wales, 354 ; in the

Sudan, 61; in U.S.A., 59, 106; strains
of, 60.

—, saltation in, 60.

— avenae on oats in Wales, 401.

— gramineum on barley in Austria, 538 ;
in Germany, 161, 169; in Norway,
202; in U.S.A., 491, 498; losses from,
in Germany, 200; perithecia of, in
California, 61; in Holland, 53; seed
treatment against, in Austria, 538 ; in
Germany, 399, 416, 509, 511, 552
(See also Pleospora trichostoma).

— oryzae on rice in Dutch E. Indies, 8;
in Japan, 139, 230; in Uganda, 157;
susceptibility of other cereals and
grasses to, in Japan, 231; temperature
relations of, 232.

— sacchari (?) on sugar-cane in Australia,
580; in Barbados, 261; in Cuba, 525,

— sativum on barley in California, 61.

— — on Hordeum murinum in California,
61.

— —on wheat in Canada, 304.

— sorokinianum on wheat in Uganda,
156, 264.

— teres on barley in Germany, 200.
also Pleospora teres).

— turcicum on maize and sorghum in
Uganda, 264.

(‘See

Hemidesmus indicus, Corticium on, in
Ceylon, 473.
Hemileia canthii, teleutospore of, on

Canthium campanulatum in Ceylon, 586.

— vastatrix on coffee in Ceylon, 7, 585 ;
in India, 448; in Uganda, 155, 156,
408 ; spraying tests against, in India,
448 ; teleutospores of, in Ceylon, 585 ;
varietal susceptibility to, in Uganda,
155.

Hemlock, see Tsuga,

620 GENERAL INDEX

Hemp (Cannabis sativa), uspulun stimu-
lates germination of, 162.

Heracleum sphondylium, Volkartia umbelli-
ferarum on, 248.

Herpetomonas, action of Euphorbia latex
on, 424.

— muscae domesticae, inoculation of
Euphorbia with, 178.

Heterodera radicicola associated with Fusa-
rium udum on Antirrhinum in Uganda,
163; with Armillaria mellea on cork
oaks in the Pyrenees, 451.

Hevea brasiliensis, see Rubber.

Hibiscus, Bacterium hibisci on, in Japan,
413.

— cannabinus, Bacterium solanacearum on,
in Sumatra, 314.

— —, root disease of, in Surinam, 107.

= — Sclerotium rolfsii on, in Sumatra,
315.

Hickory (Carya ovata); Rosellinia caryae on,
in U.S.A., 50.

Hippeastrum, amoeboid bodies in mosaic
of, 241.
Holcus lanatus, biology of Claviceps sclero-

tia on, 116.

— —, Puccinia lolii on, in U.S.A., 209.

— mollis, biology of Claviceps sclerotia on,
116.

— sorghum, see Sorghum.

— — sudanensis, see Sudan grass.

Honey, Bacillus amylovorus can live in,
452.

Hopperburn of potato in Canada, 26;
distinct from tipburn, 28.

Hops (Humulus lupulus), Fusarium be-
lieved to cause canker of, in England,
132.

—, Fusoma parasiticum on, canker prob-
ably not due to, in England, 132.

—, mosaic of, in England, 382.

—, Plasmodiophora humuli on, in Tas-
mania, 305.

—, Sphaerotheca humuli on, tests of fungi-
cides against, in England, 168.

Hordeum murinum, Helminthosporium sati-
vum on, in California, 61.

— vulgare, see Barley.

Hormiscium on timber in U.S.A., 185.

— colocasiae and H. xanthosomae synonyms
of Vasculomyces xanthosomae, 103.

Hormodendron on timber in U.S.A., 185.

Horse-radish (Cochlearia armoracia), root
rot of, in New Jersey, 109.

Humulus lupulus, see Hops.

Hyalopsora polypodii-dryopteridis, life-his-
tory and hosts of, in France, 586.

Hydrogen-ion concentration, germina-
tion of various fungi affected by, 24,
179; in relation to Actinomyces scabies,
85, 520; to Aspergillus niger, 23, 331 ;
to Colletotrichum lindemuthianum, 24; to
Fusarium of wheat, 12, 382 ; to F. lyco-
persici, 347 ; to Gibberella saubinetii, 308 ;
to Puccinia graminis, 13, 361; to Rhi-
zoctonia solani, 419, 420; toxicity of
sulphur influenced by, 460.

Hylesinus piniperda associated with Cerato-
stomella piceae and C. pini on spruce in
Britain, 50.

Hymenochaete causing brown root disease
of camphor and rubber in Ceylon and
Malaya, 291.

— noxia, see Fomes lamaoensis.

Hypochnus on coftee in Dutch E. Indies, 9.

— on rubber in Dutch E. Indies, 8.

— sacchari on sugar-cane in Cuba, 525.

— solani, see Corticium solani.

— theae on tea in Assam, 344, 345; in
Dutch E. Indies, 9.

Ice scald of stored peaches, 68.

Ink disease of chestnut in France, 188,
431.

Inonotus schini on Schinus molle in U.S.A.,
49.

Insects, fungi parasitic on, see Entomo-
genous fungi.

— as disseminators of disease, 22, 131,
148, 152, 474.

Ipomoea, Coleosporium ipomoeae on, in
U.S.A., 348.

— batatas, see Sweet potato.

Iron sulphate for control of chlorosis of
vines and fruit trees, 172, 552.

Trpex destruens on acacia and tea in Cey-
lon, 295.

Tsaria clonostachoides on tomato, 245.

— densa on cockchafers in France, 412.

Isariopsis griseola, Cercospora columnaris
synonymous with, 342.

— — on beans in Holland, 54.

Tsipinga areolata on Euclea natalensis in S.
Africa, 141.

— contorta on Trichocladus ellipticus in S.
Africa, 141.

Iska disease of the vine, see Apoplexy
of vine.

Jasmine (Jasminum), susceptible to
Pseudomonas savastanot in U.S.A., 12.

Jowar, see Sorghum.

Juglans, see Walnut.

Juncus effusus var. decipiens, Cercosporine
juncicola on, in Japan, 281.

Juniper (Juniperus), Fomes juniperinus on,
in U.S.A., 530.

— Gymnosporangium on apple and pear
associated with, in Denmark, 563.

Juniperus chinensis, Gymnosporangium asia-
ticum on, in Japan, 237.

— — var. procumbens (sargenti), Gymno-
sporangium asiaticum on, in Japan, 237.

— conferta, see J. littoralis.

— littoralis, Gymnosporangium hemisphae-
ricum and G. shiraianum on, in Japan,
238.

— procera, Fomes juniperinus on, in Kenya,
529.

— rigidis, Gymnosporangium idetae on, in
Japan, 238.

Jussieua, mosaic disease of, in Dutch E.
Indies, 35.

Jute (Corchorus), Macrophoma corchori on,
in India, 260; relation of, to Rhizoc-
tonia, 260.

Juvenile disease of oil palm in Dutch E.
Indies, 9.

Kale (Brassica oleracea var. viridis), Bac-

ee

—

GENERAL INDEX

terium campesire on, see Pseudomonas
campesiris.

[Kale], control of Plasmodiophora brassicae

on, by uspulun, 222.

— campestris on, in Bermuda,

Kalimat, active principle of, 416; con-
trol of Urocystis occulta on rye by, in
Germany, 170; use of, against cereal
diseases in Germany, 399, 416, 417.

ont thujina on Thuja plicata in Ireland,

48,

Kiggelaria africana, Fomes rimosus on, in
S. Africa, 142.

Kohlrabi (Brassica oleracea var. caulo-rapa),
Bacterium campestre on, see Pseudomonas
campestris.

— mildew of, controlled by ‘Pri’ sul-
phur, 171.

— Pseudomonas campestris on, in Bermuda,
306.

— radium action on club-root of, 494.

Kordyana, revision of genus, 341.

— celebensis on Commelina benghalensis,
341.

— —, Monotrichum commelinae parasitic
on, 341.

— pinangae, see Brachybasidium pinungae,

— polliae on Commelinaceae, 341.

— tradescantiae on Commelinaceae, 341.

Kreteschmaria micropus on rubber in
Malaya, 32.

— — on tea in India, 343.

‘Kroepoek’ disease of tobacco in Dutch
E. Indies, 9.

‘Kringrot’ disease of rubber in Dutch
E. Indies, 8.

Kuehneola fici on fig leaves in Uganda,
157.

Kurtakol, control of cereal diseases by,
in Germany, 161.

Lactic acid, promotion of sporing of
Colletotrichum lindemuthianum by, 24.

Lactuca, see Lettuce.

Laestadia on tea in Java and Sumatra, 9.

Lampong disease of Piper nigrum in
Dutch E. Indies, 87, 88.

Lantana aculeata susceptible to Bacterium
solanacearum in Sumatra, 346.

Lagenaria vulgaris var. gourda, Mycosphue-
rella citrullina on, in Japan, 16

Larch (Larix), Armillaria mellea, Fomes
annosus, F. laricis, F. pinicola, Polyporus
schweinitzii, and Trametes pini on stumps
of, in U.S.A., 531.

— mycorrhiza produced by a Rhizoctonia
in Italy, 283 ; synthesis of, with Bole-
tus elegans and Mycelium radicis sylvestris
in Sweden, 78.

— roots attacked by Mycelium radicis
abietus, in Sweden, 78.

Larix, see Larch.

Laserpitium latifolium and L. siler, Proto-
myces macrosporus on, 242.

Lasiodiplodia tubericola, see Diplodia tuberi-
cola.

Latex of plants, action of, on protozoa,
424, 523.

621

[Latex,] amoebae in, of Apocynaceae,
Asclepiadaceae, Urticaceae, and fig,
177 ; of Euphorbias, 176, 229; of let-
tuce, 177.

—, inoculation of cats and mice with
protozoa from, 229, 230, 424.

Lathyrus articulatus, L. nissolia, and L.
pratensis, Uromyces pisi on, in Moscow,
341.

— odoratus, see Sweet pea.

Laurus nobilis, die-back of, in France,
188.

Lavandula vera, see Lavender.

Lavender (Lavandula vera), Pholiota praecox
on, in France, 225.

Lead nitrate effectual as seed disinfec-
tant, 509.

Leaf curl of clover in Italy, 325.

— — of cowpea in Dutch E. Indies, 10.

— — of groundnutin Dutch E. Indies, 9.

— — of Phaseolus mungo in Dutch E.
Indies, 10.

— — of raspberry in Canada, 17, 253,
548; in U.S.A., 17, 129 ; transmission
of, by Aphis rubiphila, 548.

— — (‘krepoh’) of tobacco in Dutch
E. Indies, 9.

Leaf edge disease of apple, apricot, and
red currants in Denmark, 488.

Leaf fall of cherry in New Jersey, 110.

— — of various deciduous trees in New
Jersey, 110.

Leafhopper injury of potato, distinct
from tipburn, 28.

Leafhoppers as carriers of sugar-cane
mosaic, 381.

Leaf roll of potato, certification against,
in Canada, 332, 465; in France, 569 ;
control in British Columbia, 519; in
Denmark, 291; in France, 519; in
Pennsylvania, 443; description of,
569 ; effect of altitude on, in France,
569 ; influence of environment on, in
Canada, 519 ; in Denmark, 289 ; iodine
water test for, 569; occurrence in
Canada, 26, 255, 332, 424, 465; in
Denmark, 289, 487, 563; in Dutch E.
Indies, 8, 422; in France, 174, 288,
518, 568 ; in Germany, 200; in Hol-
land, 571; in Manitoba, 424; in
Morocco, 54; in Nebraska, 386; in
Norway, 202; in Pennsylvania, 443;
in U.S.A., 106, 569 ; phloem necrosis
in, 569; protozoa in, 227, 513; trans-
missible to deadly nightshade in Den-
mark, 563; transmission of, 175, 291,
569, 571; varietal resistance to, in
Canada, 255; in Denmark, 488; in
France, 174, 288, 518; in Germany,
175; in Holland, 571; in U.S.A., 84.

— — of tomato in Denmark, 246; in
Morocco, 54.

Leaf scald of shade trees in New Jersey,
110.

Leather, species of Penicilliwm on tanning
material and, 244.

Leek (Allium porrum), Peronospora schleideni
on, in Denmark, 488.

—, Urocystis cepulae on, in Britain, 208.

Legislation against Bacillus amylovorus in

622 GENERAL INDEX

Australia, 395; in New Zealand, 144,
274.

{Legislation | against Bacterium tumefaciens
in Washington, 278.

— against barberry in Denmark, 199;
in U.S.A., 106.

— against coco-nut diseases in Malaya,
238 ; in Tanganyika, 192.

— against Colletotrichwm gloeosporioides on
limes in Trinidad, 394.

— against Cronartium ribicola in British
Columbia, 253, 395; in Canada, 107 ;
in U.S.A., 4, 483.

— against plant diseases in Brazil, 48;_

in Malaya, 238; in Germany, 47; in
Guadeloupe and Martinique, 240; in
India, 239; in Italy, 197; in Sey-
chelles, 191; in U.S.A., 143, 240, 589 ;
in Zanzibar, 480; limitations of, 198.

— against potato diseases in Bermuda,
307; in Denmark, 199; in India,
239; in Italy, 387; in U.S.A., 480.

— against potato wart disease in Czecho-
Slovakia, 422; in Denmark, 421; in
England and Wales, 591; in Germany,
336, 421, 518; in Holland, 421; in
Italy, 387 ; in Norway, 202, 421; in
S. Africa, 10.

— against Rhamnus cathartica in Canada,
528.

— against sugar-cane diseases in India, |

239; in Malaya, 238;
528.

— against Trifolium alexandrinum in
India, 240.

— for sale of fungicides in Queensland,
591.

— proposed against diseases of ground-
nut in Africa, 350.

Leguminosae, Sclerotinia sclerotiorum on,
in Denmark, 487.

— slime bodies in sieve tubes of, 515.

Leishmania donovani and L. tropica, Euphor-
bia inoculated with, 177.

— tropica, culture of, in latex of Euphor-
bia, 424.

Lemon (Citrus limonum), see also Citrus.

—, Alternaria on, in California, 393.

—, Botrytis cinerea on, in California, 540,
542.

— gummosis, varietal resistance to, in
Argentina, 65 ; in California, 540.

—, internal decline of, in California,
392, 406.

in. Uganda,

— juice, stimulating effect of, on yeast |

growth, 284.
—, Phomopsis californica on, in California,

—~, Pythiacystis citrophthora on, in Cali-
fornia, 539, 542; temperature rela-
tions of, 542; varietal resistance to,
540.

—, shell bark of, in California, 66, 393.

—, ‘ witches’ broom’ of, in Italy, 404,

Lentinus lepideus on timber in U.S.A.,
dissemination and temperature rela-
tions of, 146.

Lenzites betulina on Celtis kraussiana, Olea
laurifolia, Pinus, and Quercus in S.
Africa, 142.

[Lenzites| guineensis, see L. betulina.

— saepiaria, cellulose and lignin-split-
ting enzymes not produced by, 284.
— — on Pinus ponderosa in Oregon, 482.

— — on slash wood in U.S.A., 531.

— — on timber in U.S.A., dissemina-
tion and temperature relations of,
146.

— —, toxicity of yellow pine crude oil
to, 51.

— trabea on timber in U.S.A., dissemina-
tion and temperature relations of, 148.

Leontodon autumnalis, Protomycopsis leonto-
dontis and P. arnoldii on, 243.

— hispidus, Protomyces kriegerianus on,
243.

— montanus, Protomycopsis arnoldii and P.
leontodontis on, 243.

Leptoporus rufo-flavus, see Fomes rufo-
Slavus.

Leptosphaeria on barley and wheat in
Denmark, 487.

— avenaria, ascigerous stage of Septoria
avenae, on oats in Wisconsin, 159.

— herpotrichoides on cereals in Germany,
200.

— —on wheat in France, control of, 11.

— michotii on rice in Uganda, 157.

— sacchari on sugar-cane in Argentina,
340 ; in Australia, 580; in Barbados,
261; in Cuba, 525 ; inthe Philippines,
109.

— tritici on wheat in Uganda, 156, 264.

Leptostroma laricinum and L. pinastri re-
ferred to Melanconiaceae, 342.

— pinastri stated to be identical with
Gloeosporium pint, 342.

Leptothyrium pomi on apple, control in
Connecticut, 220; in Ohio, 505; in S.
Africa, 536; injury caused by, in S.
Africa, 536.

Lettuce (Lactuca sativa), Amoeba lactucae
in latex of, 177.

—, amoebae from, monkeys inoculated
with, 230.

—, Aplanobacter rhizoctonia causing rosette
disease of, in Ohio, 445.

—, Bacillus carotovorus on, frogs inoculated
with, in France, 446.

—, bacterial disease of, in Arizona, 154;
in Switzerland, 303; in Texas, 256.
—, Bremia lactucae on, in Denmark, 488.

— diseases in the Pyrenees, 193.

— drop, see Sclerotinia libertiana.

— mosaic, seed transmission of, in New
York, 432.

—, Marssonia panattoniana on, in Ger-
many, 201.

—, Ozonium omnivorum on, in Arizona,
154,

—, Pythiwm on, in Bermuda, 306.

—, Sclerotinia libertiana on, in Bermuda,
306; in France, 102, 193; in New
Jersey, 102; in Pennsylvania, 444.

—, — minor on, in New Jersey, 102.

— tipburn in Colorado, 528.

Lignum vitae, see Guaiacum officinale.

Ligustrum ovalifolium susceptible to Pseudo-
monas savastanot in U.S.A., 12.

Liliaceae, Urocystis colchici on, 450.

GENERAL INDEX

Lily, Phytophthora on, in Bermuda, 306.

Lima bean, see Phaseolus lunatus.

Lime-sulphur, fungicidal value of, 168.

—, toxicity of, to Fomes lignosus, in Cey-
lon, 374.

Lime (Citrus aurantifolia and C. medica),
a gummosis of, in Mauritius,

3.
—, Colletotrichum gloeosporioides on, and
legislation against, in Trinidad, 394.
—, Gloeosporium limetticolum on, in the
Philippines, 108.

Linum angustifolium and L. catharticum,
Melampsora lini on, in Ireland, 117.

— usitatissimum, see Flax.

Liriodendron tulipifera, Torula ligniperda on,
in U.S.A., 34.

Lolium, biology of Claviceps on, 115.

— perenne, Puccinia lolii on, in U.S.A.,
209.

— —, Urocystis bolivari on, in Spain, 142.

Longitarsus parvulus carries Polyspora lini
to flax in Ireland, 116.

Loquat (Eriobotrya japonica), Entomosporium
on, in 8S. Africa, 70.

—, Fusarium on, in Uganda, 163.

—, Fusicladium on, in S. Africa, 70

—, Sclerotinia fructigena on, in N. S&S.
Wales, 120.

Loranthus, legislation against, in Zanzi-
bar, 480.

Lucerne (Medicago sativa), Ascochyta pisi
on, in Norway, 202.

—, Colletotrichum trifolii on, in Arkansas,
441; in S. Africa, 110.

—, intracellular bodies in phloem of,
515.

—, Phymatotrichum omnivorum on, in Ari-
zona, 501.

—, Rhizoctonia violacea on, in France, 371.

—, Urophlyctis alfalfae on, in France, 493.

Luffa acutangula, Mycosphaerella citrullina
on, in Ceylon, 7.

Lupin (Lupinus), Ascochyta pisit on, in
New Zealand, 504.

—, Botrytis cinerea on, in New Zealand,
504.

Lupinus, see Lupin.

Lycopersicum esculentum, see Tomato.

— pimpinnellifolium, tomato mosaic trans-
mitted to, in Indiana, 40.

Lysol as a fungicide against bunt of
wheat, 74.

Macowaniella congesta on Carissa arduina in
S. Africa, 141.

Macrophoma corchori in relation to Rhizoc-
tonia, 260.

— — on jute in India, 260.

— cucurbitacearum and M. decorticans pos-
sibly synonyms of Ascochyta cucumis,
342. :

— destruens on citrus in W. Australia,
395.

— nicotianae on Nicotiana tabacum in St.
Thomas Island, 589.

— theicola on tea in Ceylon, 7.

Macrosiphum solanifolii transmits mosaic
disease of bean, 77.

Macrosporium on dates in Arizona, 154.

623

[ Macrosporium] on tomato in Indiana, 41 ;
in Morocco, 54.

— curotae on carrot in U.S.A., 6, 352.

— caudatum on Zinnia in Denmark,
488.

— cladosporioides, biometrics of, 391.

— cucumerinum, see Cladosporium cucume-
rinum.

— longipes on tobacco in S. Africa, 476.

— melojhthorum on Cucurbitaceae in
Denmark, 488. (See also Cladosporium
cucumerinum).

— parasiticum on garlic in Spain, 191.

— sarcinaeforme, nutrient requirements
of, 83.

— —, toxicity of sulphur to, 460.

— solani on tomato, 245; in Denmark,
246.

— tomato on tomato, 245,

Maguey, see Agave cantula.

Magnesium deficiency causing ‘sand
drown’ of maize and tobaccoin U.S.A.,
80, 421.

Maize (Zea mays), Acrothectum on, in
India, 259.

— bacteria on, in U.S.A., 106.

—, bacterial root rot of, in Arkansas,
441.

—, Cephalosporium on, in U.SA., 106.

—, — sacchari on, in Missouri, 213.

—, Diplodia on, in India, 259.

—, — zeae on, in Illinois, 447; in India-
na, 56; in Missouri, 213; in Ohio,
442; in Pennsylvania, 442; in Wis-
consin, 106; in U.S.A., 257; varietal
resistance to, in Indiana, 56.

—, endosperm character and disease re-
sistance of, 56.

—, Fusarium on, in India, 259; in India-
na, 56.

—, — moniliforme on, in Missouri, 213 ;
in Pennsylvania, 442; in Wisconsin,
257 ; in U.S.A., 106.

—, Gibberella saubinetii on, in Missouri,
213; in Pennsylvania, 442; in Wis-
consin, 257, 536; in U.S.A., 106;
temperature and moisture relations
of, 257, 536,

—, Helminthosporium oryzae on, in Japan,
231.

—, — turcicum on, in Uganda, 264.

— mosaic, amoeboid bodies in, 134;
Aphis maidis can transmit, 33, 236;
hosts of, 584; Peregrinus maidis can
transmit, 33; transmitted to and
from sugar-cine, 33, 236,241; varietal
resistance to, in Georgia, 585.

—, mycorrhiza of, in Italy, 172, 173.

—, Penicillium on, in Indiana, 56.

—, Pseudomonas alboprecipitans can infect,
447,

—, —dissolvens on, in Arkansas, 158,

—, Puccinia maydis on, germination of
teleutospores of, in Missouri, 179; oc-
currence in Uganda, 264.

—, Puccinia sorghi on, see P. maydis.

— ‘sand drown’ caused by magnesium
deficiency in U.S.A., 81, 421.

—, Sclerospora on, in Uganda, 156, 264,

—, — javanica on, in Dutch E, Indies, 9.

624

[Maize, Sclerospora] philippinensis and S.
spontanea on, in the Philippines,
359.

—, Ustilago maydis, see U. zeae.

—, — zeae on, influence of ultra-violet
and X-rays on, 324; occurrence in
Astrakhan, 207; in Canada, 255.

Man, Allescheria boydii on, in Texas,
226.

—, physiology of fungi pathogenic to,
410.

—, Sporotrichum carougeant N sp. on, in
Madagascar, 21.

Manganese, control of grey speck dis-
ease of oats by, 403.

Mango (Mangifera indica), ripe rot of, in
British Guiana, 355.

Mangold (Beta rugaris), bacterial disease
of, in Switzerland, 303.

— mosaic in Britain, 208.

—, Peronospora schachtii on, in Germany,
4814.

—, uspulun stimulates germination of
seeds of, 20.

Manihot, Septobasidium bogoriense on, in
Java, 145.

— utilissima, see Cassava.

Manila hemp, see Musa textilis.

Maple, see Acer.

Marasmius on Musa textilis in the Philip-
pines, 108.

— root rot disease of sugar-cane in Aus-
tralia, 580; causation of, doubted in
Argentina, 340; in Barbados, 260,
467.

— perniciosus on cacao in British Guiana,
355.

— sacchari on sugar-cane in Barbados,
260, 467; in Cuba, 525; in Guade-
loupe, 33; (?)in Java, 469; in the
Philippines, 109.

— stenophyllus on sugar-cane in Cuba,
525.

Marguerite, Bacterium tumefaciens on, in
Denmark, 488.

Marrow, see Vegetable Marrow.

Marsdenia, Septobasidium bogoriense on, in
Java, 145.

Marssonia panationiana on lettuce in Ger-
many, 201

— potentillaeg on strawberry in Canada
and U.S.A., 15; is conidial stage of
Mollisia earliana, 16; varietal suscepti-
bility to, 16.

Martynia louisiana, cucumber
transmissible to, 512.

Matthiola, see Stocks

Medicago sativa, see Lucerne.

Melaleuca leucodendron, wet root rot fungus
on, in Uganda, 157.

Melampsora lini, biologic specialization in,
117.

— — on Linum angustiflium and L.
catharticum, in Ireland, 117.

— — on flax in Canada, 304; in Ire-
land, 117; in Morocco, 54.

— pinitorqua on pines in Cyprus, 529.

Melampsorella caryophyllacearum, hosts of
aecidial stage (Peridermium elatinum) of,
431,

mosaic

GENERAL INDEX

ne on conifers, notes on,

42.

Melanconium on tomato, 245.

— sacchari on sugar-cane in Argentina,
339, 340; in Australia, 580; in Cuba,
525 ; in the Philippines, 109.

Melanomma medium on citrus in Spain,
405,

Melanopsammopsis ulei on Hevea rubber in
British Guiana, 354.

Melanose of citrus, see Phomopsis citri.

Melanospora zamiae on rice in Uganda,
157.

Melia azedarach, Fomes conchatus on, in S.
Africa, 142.

Melica ciliata, biology of Claviceps sclerotia
on, 115.

Melilotus resistant to Sclerotinia trifoliorum
in British Columbia, 395.

Meliola on citrus in the Philippines,
108.

— arundinis on sugar-cane in the Philip-
pines, 109.

— citri on citrus in Spain, 405.

— penzigi on citrus in Spain, 405.

Melon (Cucumis melo), Cladosporium cu-
cumerinum on, in Norway, 208.

—, Fusarium solani transmitted by larval
faeces to, 561.

—, Mycosphaerella citrullina on musk-, in
Japan, 16.

—. Oidium on, in Astrakhan, 207.

—. Orobanche aegyptiaca on, in Astrakhan,
207.

—, Pseudoperonospora cubensis on, in Mas-
sachusetts, 440.

—, Sclerotinia libertiana on, in France,
102.

Mentha arvensis, Rhizoctonia vicolacea on, in
England, 451.

Mercury compounds, fungicidal proper-
ties of, 557; stimulating action of,
18, 20, 161, 162, 509, 510, 551, 552;
use of, against beet diseases, 18, 224,
510; against cereal diseases, 19, 161,
170, 171, 202, 281, 416, 511, 550, 551,
555, 557. :

Merulius lacrymans (?) on asphalt shingles,
187.

Metarrhizium anisopliae parasitic on Cleonus
punctiventris, 412.

— — weakly parasitic on Oryctes rhino-.
ceros in Ceylon, 370.

Mice inoculated with latex protozoa in
France, 229.

Microcera fugikuroi parasitic on various
insect pests of citrus in Florida, 369.
Microsphaera alni and M. alni var. quercina,

oak mildew referred to, 293.

— alphitoides, see M. quercina.

— betae, beet mildew resembling, in
France, 102.

— quercina causing oak mildew in Italy,
293, 294; spread from cultivated to
wild hosts in Denmark, 563.

Microsporon audouini, M.lanosum, M. fulvum,

and M. pubescens, physiology and toxie
action of, 410.
Microstroma, taxonomy of, 167.

| — tonellianum on plum in Italy, 166;

GENERAL INDEX

relation of, to Awreobasidium vitis var. |

album, 167.

Millet (Italian), see Setaria italica.

Mimosa inevisa resistant to Bacterium
solanacearum in Sumatra, 295, 346.

— —, Sclerotium rolfsii on, in Sumatra,
295.

Miscanthus sinensis susceptible to sugar-
cane mosaic, 584, 585.

Mites infesting fungus cultures, 325.

Molinia coerulea, biology of Claviceps
sclerotia on, 115.

Mollisia earliana on strawberry in Canada
and U.SA., 16, 255.

Monilia, influence of CO, and temperature
on, 26.

— on cherry in Germany, 201, 457;
varietal resistance to, 457.

— on elm in Holland, 2.

— on fruit trees, ‘solbar’ against, in
Germany, 132.

— candida carried by Xyleborus dispar,
561.

— cinerea on peach in Holland, 94.

Moniliopsis aderholdi on cinchona in Duteh
E. Indies, 10.

— — on garden plants in Germany,
283.

— —, relations between Rhizoctonia solani
and, 470.

Monilochaetes infuscans on sweet potato in
New Jersey, 31.

Monotrichum commelinae parasitic on Kor-
dyana celevensis in Dutch E. Indies,
341.

‘ Mopog’, see Moniliopsis aderholdi.

Morphea citri on citrus in Spain, 405.

Morus, Septobasidium bogoriense on, in Java,

145. (See also Mulberry).
Mosaic diseases, cross inoculations
with, 21.

— of ash in England, 489.

— of Phaseolus radiatus var. aurea in
Japan, 52.

— of beans in Norway, 203; protozoa
associated with, in U.S.A., 227, 514;
transmitted by Macrosiphum solanifolii
i U.8,A.,: 77

— of beet in Britain, 208; in Denmark,
487.

— of blackberry in New York, 352,

— of Chinese cabbage, amoeboid bodies
in, 241.

— of clover in Arkansas, 441 ; protozoa
in relation to, 227, 514, 515; relation
of temperature to, in U.S.A., 77.

— of cowpea in Arkansas, 441.

— of cucumber, hosts of, 512; intra-
cellular bodies in relation to, 514;
occurrence in California, 152; in
England, 489; carried in seed, 491;
transmission of, 107, 512, 513; two
types of, in Britain, 491.

— otf Cucurbita in Sumatra, 35.

— of cucurbits, hosts of, 512.

— of dewberry in New York, 352.

— of eggplant, disease resembling, in
Astrakhan, 535.

— of grasses, hosts of, 241, 584; not
transmitted by seed, 585; transmitted

625

by Aphis maidis, 585. (See also Maize
and Sugar-cane mosaic).

[Mosaic] of Hippeastrum, amoeboid bodies
in, 241.

— of hops in England, 382.

— of Jussiewa in Sumatra, 35.

— of lettuce transmitted by seed in New
York, 432.

— of maize, amoeboid bodies in, 134;
Aphis maidis can transmit, 33, 236;
hosts of, 584 ; transmitted by Peregrinus
maidis, 33; transmitted to and from
sugar-cane, 33, 236, 241; varietal re-
sistance to, in Georgia, 585. (See also
Grass and Sugar-cane mosaic).

— of mangold in Britain, 208.

— of Melilotus in Arkansas, 441.

— of Passiflora in England, 489.

— — — foetida in Sumatra, 35.

— of pea-bean, effect of temperature on,
77

‘.

— of Petunia in England, 489, 491 ; intra-
cellular bodies in phloem of, 513.

— of Physalis in Sumatra, 35 ; in U.S.A.,
40, 474, 518.

— of potato, amoeboid bodies in, 134;
certification against, in Canada, 332,
465; in France, 569; control by
roguing in British Columbia, 519; in
U.S.A., 106; by use of unripe seed
tubers in Germany, 519; in Holland,
572; factors influencing, 77, 519;
intracellular bodies in phloem of, 613;
occurrence in Astrakhan, 535; in
Canada, 26, 332, 424, 465, 519; in
Denmark, 487; in Dutch E. Indies,
422; in England, 489, 491 ; in France,
288; in Germany, 175, 200; in
Morocco, 54; in Nebraska, 386; in
Norway, 202; in U.S.A., 106; trans-
missible from cucumber and possibly
to Phytolacca, 513; transmission of,
175; from wild plants in Holland,
571; varietal resistance to, in Den-
mark, 488; in France, 288; in Ger-
many, 175; in Holland, 571; in
Ontario, 255 ; in U.S.A., 84, 106.

— of raspberry in Canada, 17, 253, 547 ;
in New York, 351, 546; in U.S.A., 17,
129; transmission of, probably by
Aphis rubiphila, 548.

— of solanaceous weeds in tobacco
plantations in Sumatra, 35.

— of Solanum dulcamara transmitted
from tomato in England, 491.

— — — carolinense transmitted to to-
bacco in Florida, 474,

— — — nigrum transmitted from tomato
in England, 489, 491 ; in Indiana, 40,

— of sorghum, 584 ; in Hawaii, 241; in
Java, 236.

— of soy-bean, effect of temperature on,
éé.

— of Sudan grass in Hawaii, 241.

— of sugar-beet in Britain. 208.

— of sugar-cane, amoeboid bodies in,
241; control in Argentina, 339; in
Australia, 579, 581; in Cuba, 524,
525; in Hawaii, 241; in Java, 34,
237; in the Philippines, 141; in

626

Porto Rico, 106; in Trinidad, 394; in
U.S.A., 106; effect of sunlight on,
242; hosts of, 33, 34, 236, 241, 390,
584; occurrence in Argentina, 339;
in Australia, 579; in Barbados,
260; in Cuba, 524, 525; not in
Guadeloupe, 33; in Hawaii, 33, 241;
in Java, 8, 33, 34, 237; not in
Mauritius, 203; in the Philippines,
88, 109, 141, 468; in Porto Rico, 106,
890; in Trinidad, 394; in U.S.A.,
106, 205 ; transmitted by Aphis maidis,
381, 585; in Cuba, 524; in Hawaii,
33, 241 ; in Java, 237; in Porto Rico,
390; by Peregrinus maidis, 381; pos-
sibly by Aphis sacchari in Argentina,
339; in Java, 237; possibly by Caro-
linaia, 381; varietal resistance to, in
Argentina, 339; in Cuba, 524, 525;
in Java, 34, 257 ; in the Philippines,
89, 141, 468; in U.S.A., 106. (See
also Grass and Maize mosaic).

[Mosaic] of sweet potato in Arkansas,441.

— of tobacco, effect of temperature on,
77; intracellular bodies in, 513;
occurrence in Dutch E. Indies, 9, 35;
in England, 489, 491; in Florida,
474; in the Philippines, 109; in the
Transvaal, 477 ; size of virus particles
of, 133; transmitted from cucumber
through Capsicum in U.S.A., 513; from
tomato in England, 491 ; from other
Solanaceae in Florida, 474; in Suma-
tra, 35.

— of tomato, aphids and probably flea-
beetles transmit, 40; carriers of, in
England, 491; effect of temperature
on, 77; hosts of, in England, 491;
in Indiana, 40; occurrence in Astra-
khan, 535; in Denmark, 246; in
England, 547, 489; in Indiana, 40;
protozoa in, 227 ; intracellular bodies
in, not protozoa, 514, 516 ; transmitted
to Petunia, Solanum, and tobacco in
England, 491 ; to Lycopersicum, Physalis,
and Solanum in Indiana, 40.

— plants, amoeboid bodies in, 134, 241;
protozoa in, 227; various bodies in
phloem of, not protozoa, 513-516.

Mottle necrosis of sweet potato in
U.S.A., 486.

Mottling of coffee leaves in Dutch E.
Indies, 9.

Mould of sheet rubber, prevention of,
139, 427, 578.

Mucor on ginseng in Korea, 503.

— on rubber in Malaya, 396.

— on timber in U.S.A., 185.

— stolonifer, enzymes and toxins of, 81.

Mulberry (Morus), Bacterium mori on, in
S. Australia, 292.

Musa sapientum, see Banana.

— textilis, heart rot of, in the Philip-
pines, 108,

— —, Marasmius on, in the Philippines,
108.

— —, Phoma musae on, in the Philip-
pines, 108.

— —, root rot of, in the Philippines, 108.

Mustard (Brassica alba and B. nigra),

GENERAL INDEX

Plasmodiophora brassicae on, in Den-
mark, 487; in Germany, 432; in
Norway, 203; tests with uspulun
against, 222.

{Mustard] (Indian) (Brassica campestris
var. sarson), Urocystis coralloides on, in
India, 259.

Mycelium radicis abietis parasitic on larch
in Sweden, 78.

— — fagi in beech mycorrhiza in Ger-
many, 463.

— — sylvestris in larch mycorrhiza in
Sweden, 78.

Mycelophagus castaneae suggested cause of
chestnut ink disease in France, 188.
Mycological works published in 1920,

226 ; in 1922, 417.

Mycorrhiza of Alnus viridis in Italy, 283.

— of barley in Italy, 173.

— of beech in Germany and Tyrol, 463.

— of Calluna, 326; synthesis of, 327.

— of cereals and other plants in Italy,
Rhizoctonia associated with, 283.

— of Dipodium punctatum in N.S. Wales,
78, 79.

— of larch in Italy, Rhizoctonia associated
with, 283 ; in Sweden, synthesis of ,77.

— of maize in Italy, 172, 173.

— of oats in Italy, 173.

— of orchids, 134.

— of rye in Italy, 173.

— of wheat in Italy, 172.

—, two distinct fungi nearly always con-
cerned in forming, 283.

Mycosphaerella cerasella on cherry and
other species of Prunus in Japan, 416.

— citrullina on Lagenaria vulgaris var.
gourda in Japan, 16.

— — on Luffa acutangula in Ceylon, 7.

— — on musk-melon in Japan, 16.

— on watermelon in U.S.A., 280.

— fragariae on strawberry in Illinois,
control, 455.

— grossulariae on currants and goose-
berry in Illinois, control, 454.

— pinodes, see Ascochyta pisi.

— rubina on raspberry in U.S.A., 278.

— sentina on pear in Switzerland, 275,

~ 802. ;

— striatiformans, leaf stripe of sugar-cane
in Argentina not due to, 340.

Myxosporium corticolum on apple in Eng-
land, 209.

Nadsonia elongata, growth inhibited by
Spicaria purpurogenes, 567.

Narcissus, Botrytis on, in England, 489.

Nasturtium (Tropaeolum), Bacterium tume-
faciens causes fasciation and prolepsis
of, 10.

Naucoria suborbiculata on sugar-cane in
Argentina, 340.

Nectarine (Prunus persica), Exoascus de-
formans on, in New Zealand, 373.

—, Puccinia pruni-spinosae on, in
Zealand, 320.

—, Sclerotinia cinerea on, in New Zea-
land, 275.

Nectria cinnabarina on fruit trees in New
Zealand, 319.

New

GENERAL INDEX

[Nectria cinnabarina| on red currant in
England, 320.

— coccinea, differences between N, galli-
gena and, 90.

— —on apple in Oregon, 90.

— gualligena, differences between JN.
coccinea and, 90.

— —, Fusarium willkommii conidial stage
of, 90, 218.

— —on apple in Crimea, 172; in Eng-
land, 318; and pear in Oregon, 90,
206 ; Venturia inaequalis aids infection
by, 318.

— hematochroma, Fusarium stage causes
gummosis of citrus in Argentina, 62.
eas blight of stone pine in Italy,
Nematodes transmit disease in soil, 561.
Nematospora phaseoli on Lima bean in Vir-

ginia, 194.

sy haa malicorticis on apple in Oregon,

Nerium oleander, see Oleander.

ca disease of date in Argentina,

Nicotiana, see Tobacco.

pee? Fusarium udum on, in Uganda,
163.

Nitrogen fixation by bacteria in leaves
ot Chomelia asiatica, 418.

Northiella sacchari on sugar-cane in Aus-
tralia, 579.

— —, proposed alteration of name to
Phytamoeba sacchari, 235. (See also
Fiji disease of sugar-cane).

‘Nosperal’ against apple mildew in
Germany, 223,

Nozema united with Phytophthora, 183.

Nummularia discreta on apple in Illinois,
control, 270; varietal susceptibility
to, 270.

Oak (Quercus), Armillaria mellea on, in
U.S.A., 481 ; on cork-, in France, 431.

—, Cronartium conigenum can infect, in
U.S.A., 3.

—, — strobilinum can infect, in U.S.A., 3.

—, Lenzites betulina on, in 8. Africa, 142.

—, Microsphaera quercina on, in Den-
mark, 563 ; in Italy, 293, 294.

—, Polyporus igniarius consumes tissue
elements of, equally, 284.

—, — sulphureus on, in 8. Africa, 142.

—, sap-stain of, in U.S.A., 185.

— timber decayed by Phellinus (Fomes)
cryptarum in Versailles Palace, 97.

—, Torwla ligniperda on, in Europe, 34.

Oats (Avena sativa), Bacterium coronafaciens
on, in Britain, 208, 401; var. atro-
purpureum on, in U.S.A., 357.

—, bright speck disease of, in Denmark,
488 ; in Norway, 202.

—, Erysiphe graminis on, in Wales, 401.

—, grey speck disease of, control and
oceurrence, 403; similarity to sugar-
cane root rot, 526.

—, Helminthosporium avenae on, in Wales,
401.

—, Leptosphaeria avenaria on, in Wiscon-
sin, 159,

627

[Oats], mycorrhiza of, in Italy, 172.

—, Pseudomonas alboprecipitans can infect,
447,

—, Puccinia coronata on, see P. lolii.

—, — graminis on, in Canada, 303; in
Denmark, 563 ; in Wales, 401 ; breed-
ing for resistance to, in U.S.A, 210.

—, — lolii on, alternate hosts of, in
US.A., 209; biologic specialization
of, in U.S.A., 209 ; legislation against,
in Canada, 528; occurrence in Bri-
tain, 208; in Canada, 255, 303, 528 ;
in U.S.A., 209; in Wales, 401.

—, seed disinfection tests with, in Ger-
many, 511, 551; in Sweden, 19.

—, Septoria avenae (pyenidial stage of
Leptosphaeria avenaria) on; in Wiscon-
sin, 159.

—, — graminum on, in Morocco, 54.

—, soil acidity disease of, in Germany,
200, 499.

—, Ustilago avenae on, control in Austria,
538; in Canada, 253, 256, 549; in
Czecho-Slovakia, 550; in Germany,
161, 169, 170, 399, 417, 504 ; in Wales,
400 ; cultures of, in Russia, 587 ; in-
fluence of fertilizers on, in Germany,
504; method of infection by, 214;
occurrence in Austria, 538 ; in Canada,
253, 255, 303, 549; in Czecho-Slo-
vakia, 550; in Denmark, 487; in
Germany, 161, 169, 170, 200, 214, 399,
417, 504; in Russia, 587; in Wales,
400, 401.

—, — levis on, in Canada, 304, 459; in
U.S.A., 458 ; in Wales, 401.

Ocotea bullata, Fomes geotropus on, in S.
Africa, 142.

Oenothera, genetics of resistance to Pry-
siphe polygoni in, 75.

Oidium on avocado pear in Bermuda,
306.

— on. beet in France, 101.

— on cucumber in Astrakhan, 207.

— on melons in Astrakhan, 207.

—onrubber in Dutch E. Indies, 8; in
Uganda, 155, 156.

—'on timber in U.S.A., 185.

— on tobacco in Dutch E. Indies, 9; in
S. Africa, 477.

— on vegetable marrow in Astrakhan,
207.

— cydoniae on quince in Switzerland,
302.

— lactis, Spicaria purpurogenes
growth of, 567.

— lycopersici on tomato in Germany,
201.

— quercinum, see Microsphaera quercina.

— tuckeri, see Uncinula necator.

Oil palm (Elaeis guineensis), bud rot of, in
Dutch E. Indies, 9; in Surinam, 107.
—, crown or juvenile disease of, in

Dutch E. Indies, 9.

—, Fomes applanatus and F, senex on, in
St. Thomas Island, 589.

—, obscure disease of, resembling coco-
nut bud rot, in Malaya, 396.

Olea, Fomes yucatensis on, in 8. Africa,
142.

inhibits

628

[ Olea] europaea, see Olive.

— laurifolia, Fomes annularis, F. applana-
tus, F. australis, F. leucophaeus, F. rimosus,
and F. vegetus on, in S. Africa, 142.

— —, Lenzites betulina on, in S, Africa,
142.

— —,Polyporus lucidus on,inS. Africa, 142.

— verrucosa, Polyporus lucidus on, in S.
Africa, 142.

Olive (Olea europaea), Bacterium olivae on,
in Italy, 322.

—, — savastanoi, see Pseudomonas sava-
stanoi.

—, Cycloconium oleaginum on, in Morocco,
54.

—, Pseudomonas savastanoi on, in Italy,
415; in US.A., 12.

Omphalia saccharicola on sugar-cane in
Argentina, 340,

Onion (Allium cepa), Colletotrichum circinans
on, in S. Australia, 292; relation of
pigment to resistance to, 492.

—, Fusarium mali on, in Bermuda, 306 ;
in Ontario, 436.

—, Peronospora schleideni on, in Bermuda,
306.

—, Urocystis cepulae on, control in U.S.A.,
206, 460; life-history of, 251; oe
rence in Britain, 208; in U.S.A., 20
251.

—, Vermicularia circinans on, see Colle-
totrichum circinans.

Oospora hyalinula on citrus in Spain, 405.

— lactis on tomato in New Jersey, 91.

— pustulans on potato in Canada, 26 ; in
England, 390, 567 ; relation to Spongo-
spora subterranea, 389, 567.

Ophiobolus on barley and wheat in Den-
mark, 487,

— cariceti on wheat, influence of various
chemicals on, 11; occurrence in
Britain, 208; in France, 11; in N.S.
Wales, 354; in S. Africa, 536; in
U.S.A., 106, 206.

— graminis, see O. cariceti.

— herpotrichus on cereals in Germany,
200.

Opuntia, biological control of, in Austra-
lia, 397.

Orange (Citrus aurantium, C. sinensis, etc.),
see , also Citrus.

—, Alternaria on, in N.S. Wales, 354.

—, — citri on, in U.S.A., 214, 309.

—, bark rot of, in the Philippines, 108.

—, Colletotrichum gloeosporioidzs on, in N.S.
Wales, 354; in the Philippines, 108.

—, Coniothectum scabrum on, in S. Austra-
lia, 292.

—., Cytosporina citiiperda on mandarin, in
Italy, 310.

—, Diplodia citricola on, in S. Australia,
292.

—, — natalensis from grapefruit can in-
fect, 65.

—, Gloeosporium psidii on, in Mexico, 414.

— gummosis in Argentina, 62 ; in Cali-
fornia, 539, 542; various fungi can
cause slight, 541.

—, Penicillium digitatum causes rise in
temperature of, 83.

GENERAL INDEX

[Orange], Phoma citricarpa on, in N. S.
Wales, 354.

—_— macrophoma on, in §. Australia,
292.

—, Phomopsis caribaea doubtfully parasitic
on, 65.

—, Phytophthora parasitica on, in Cali-
fornia, 540, 542; in the Philippines,
108.

—, — terrestris on, see P. parasitica.

—, Pseudomonas citri on, in the Philip-
pines, 62, 63; introduced into U.S.A.
on Japanese oranges, 143; relation of
stomata to infection by, 62; relation
of tissue maturity to infection by, 63 ;
varietal reaction to, 62, 64.

—, psorosis or scaly bark of, in the
Philippines, 108.

—, Pythiacystis citrophthora on, in Cali-
fornia, 539, 542; in S. Australia, 309;
temperature relations of, 542; resis-
tance to, 540.

—, root rot of bitter, in Italy, 404.

—, Septoria depressa on, in S. Australia,
292.

—, sooty mould of, in Argentina, 64.

Orchid mycorrhiza, 134.

Orobanche aegyptiaca on cabbage, eucurbits,
eggplant, and tomato in Astrakhan,
207.

Oryctes rhinoceros, coco-nut bud rot attri-
buted to, 268.

— —, Metarrhizium anisopliae weakly
parasite on, in Ceylon, 370.

Oryza sativa, see Rice.

Osmanthus aquifolium, Pseudomonas savasta-
noi can infect, 12.

Oxyanthus tubiflorus, Corticium on, in Cey-
lon, 473.

Ozonium omnivorum, hibernation of, in
Texas, 256,

— — on cotton in U.S.A., 154, 441, 501.

— — 6n lettuce in Arizona, 155,

— — on lucerne in Arizona, 501,

Palawaniella eucleae on Euclea macrophylla

in 8. Africa, 141.

Palm seedling disease in N. 8. Wales,

354.

—, see also Areca, Coco-nut, Oil palem:
Panax quinguefolium, see Ginseng.
Panicum colonum, Aphis maidis and A.

sacchari on, in connexion with sugar-

cane mosaic in Java, 34, 236.

— crus-galli, Helminthosporium oryzae on,

in Japan, 231.

— —, possible spread of sugar-cane

mosaic from, 33,

— dichotomiflorum, sugar-cane mosaic can

infect, 584.

— miliaceum, Helminthosporium oryzae on,

in Japan, 231.

— repens and P. ramosum, Piricularia re-
sembling P. oryzae on, in India, 259.
— sanguinale, Helminthosporium oryzae on,

in Japan, 231.

— —, Piricularia resembling P. oryzae on,

in In@ia, 259.

— —, possible spread of sugar-cane

mosaic from, 33, 34.

GENERAL INDEX 629

Papaw (Carica papaya), Erysiphaceous
fungus on, in Bermuda, 306.

—, Phytophthora faberi on, in Ceylon, 7.

—, Pucciniopsis caricae on, in Bermuda,
306.

‘ Parakol’ as a fungicide against Phyto-
phthora on rubber, 140.

Parastigmatea nervisita on Stephania her-
nandifolia in S, Africa, 142.

Paritium, Septobasidium bogoriense on, in
Java, 145.

Parsley (Petroselinum sativum), Bacillus
nelliae on, in the Philippines, 445.

Parsnip (Pastinaca sativa), Cercospora apii
on, in S. Australia, 292.

—, Protomyces macrosporus on, 242.

Paspalum boscianum, sugar-cane mosaic
can infect, 584, 585.

— sanguinale, see Panicum sanguinale.

Passiflora, mosaic of, in England, 489;
woodiness of, in N. S. Wales, 354.

— foetida, mosaic of, in Sumatra, 35.

Passion flower, see Passiflora.

Pastinaca sativa, see Parsnip.

Pavetta indica, nitrogen fixing leaf nodules
of, 418.

Pea-bean mosaic, effect of temperature
on, 77.

Peach (Prunus persica), Botrytis cinerea on,
in Holland, 94.

—, brown bark spot of, in U.S.A., 221.

—, Cladosporium carpophilum on, in Cali-
fornia, 127; in Connecticut, 220; in
Illinois, 454; in New Jersey, 506;
varietal resistance to, in California,
127.

—, — herbarum on, in Holland, 94.

—, Cytospora prunorum on, in Holland,
94

—, die-back of, in Holland, 94.

—, Exoascus deformans on, in Astrakhan,
535 ; in California, 374; in Germany,
166; in Illinois, 454; in Michigan,
73; in New York, 546; in New Zea-
land, 165, 373; sulphur fungicides
against, in New Jersey, 506.

—, ice scald of, 68.

—, improvements in spraying, in U.S.A.,
225.

—, Monilia cinerea on, in Holland, 94.

—, Polyporus versicolor on, in S. Africa, 142.

—, Pseudomonas pruni on, in U.S.A.,
219.

—, Puccinia pruni-spinosae on, in Bermuda,
306 ; in New Zealand, 320,

—, Sclerotinia cinerea on, control in Austra-
lia, 69; in Illinois, 454; in Michigan,
72; in New Jersey, 506; in New
Zealand, 275.

—, — fructigena on, control in Australia,
276; in Connecticut, 220.

—, Sphaerotheca pannosa on, in Crimea,
172.

—, Stereum purpureum on, in New Zea-
land, 68; in S. Africa, 451, 452.

—, Traneschelia punctata on, see Puccinia
pruni-spinosae.

—, Ustulina zonata on, in Kenya, 260.

Peanut, see Groundnut.

Pear (Pyrus communis), Armillaria mellea

on, varietal resistance to, in California,
394,

[Pear], Bacillus amylovorus on, control in
California, 125, 394, 546; in New Zea-
land, 273; in U.S.A., 274 ; dissemina-
tion by bees, 125; legislation against,
in New Zealand, 144, 274; losses from,
in California, 125; occurrence in
Canada, 304; in New Zealand, 273;
in U.S.A., 125, 163, 274, 394, 546;
varietal resistance to, in U.S.A., 125,
126, 274, 394.

—, brown bark spot of, in U.S.A.,
221.

—, chlorosis of, in S. Africa, 353.

—, Coniothecium chomatosporum on, in
Queensland, 122; in S. Africa, 271;
in S. Australia, 292.

—, Corticum salmonicolor on, in Mauritius,
203.

—, Fabraea maculata on, in New Jersey,
110; in S. Africa, 71.

—, Fusarium gemmiperda on, in Holland,
53.

—, — willkommii on, in Denmark, 218;
in Oregon, 90, 206.

—, Fusicladium pirinum on, see Venturia
pina,

—, Fusicoccum on, in Holland, 53.

—, Ganoderma sessile on, in Argentina,
Ae

—, Gymnosporangium on, associated with
junipers in Denmark, 563.

—, — sabinae on, in Astrakhan, 535; in
Crimea, 172.

—, Mycosphaerella sentina on, in Switzer-
land, 275, 302.

—, Nectria coccinea on, in Oregon, 90.

—,— galligena on, in Oregon, 90, 206.

—, Phacidiella discolor on, in Switzerland,
273.

—, Phomopsis ambigua (?) on, in Holland,
53.

—. — mali on, in California, 393.

—. Physalospora cydoniae on, in Astrakhan,
535.

—, Phytophthora cactorum on, in U.S.A.,
433. :

—, Roesleria hypogaea on, in Holland,
53.

—, Septoria piricola on, in Astrakhan,
535.

—, Sphaeropsis malorum on, see Physalo-
spora cydoniae.

—, spray injury to, in Denmark, 488.

—, Stereum purpureum on, in New Zea-
land, 68; in S. Africa, 452.

—, Ustulina zonata on, in Kenya, 260.

—, Venturia pirina on, ascospore ejection
in, 122; control in Germany, 169; in
Illinois, 454; in Michigan, 72; in
New Zealand, 121; in S. Africa, 126;
occurrence in Astrakhan, 207, 535 ;
in Crimea, 172; in Denmark, 218;
in Germany, 169; in Illinois, 454;
in N.S. Wales, 353; in New Zealand,
121, 122.

—, Xylaria polymorpha on, in Switzerland,

—, Japanese sand, see Pyrus sinensis.

630

Peas (Pisum), Ascochyta pisi on, in Den-
mark, 487; in New Zealand, 505.

—, bacterial disease of, in Switzerland,
303.

—, Fusarium on, in Canada, 304; in
New Zealand, 432.

—, — vasinfectum on, in Germany, 201.

—, intracellular bodies in phloem of,
514.

—, Sclerotinia sclerotiorum on, in Denmark,
487.

—, Thielavia basicola on, in Switzerland,
303.

—, Uromyces pisi on, specialization of, in
Russia, 341.

Pecan (Carya), Coniothyrium caryogenum
not the cause of kernel spot of, in
U.S.A., 283.

—, Fusicladium effusum on, in Mississippi,
44],

— rosette in Georgia, 135.

Pectinase secretion by Rhizopus, 418,
565 ; effect of temperature on, 464.
Pelargonium, action of radium on crown

galls of, 494.

—, Bacterium erodii on, 371.

—, — pelargonii on, in U.S.A., 370.

—, fasciation of, produced by Bacterium
tumefaciens, 10.

—, Pythium de Baryanum on, in Holland,
54.

Penicillium, apical growth of, 588.

— on apples in New Zealand, 125.

— on maize in Indiana, 56.

— on timber in U.S.A., 185, 186.

— on tomato in England, 347.

— crustaceum on stored quinces in Italy,
167, 168.

— decumbens in the leather industry,
244,

— digitatum on citrus in Spain, 405;
causes a rise of temperature in the
fruits, 83.

— expansum in the leather industry,
244,

— — on stored apples in U.S.A., 456.

— glaucum, effect of CO, and tempera-
ture on, 25.

— — growth of, inhibited by Spicaria
purpurogenes, 567.

— — on apple in Denmark, 218.

— — on citrus in Spain, 405.

— —, toxins of, 81.

— lanosum in the leather industry, 244.

— roseum, citrus gummosis can be caused
by, in California, 541, 543.

— viridicatum in the leather industry, 244.

Pennisetum glaucwm, sugar-cane mosaic
can infect, 584.

— purpureum, Sphacelia on, in Uganda,
264.

— spicatum, Sphacelia on, in Tanganyika,
264,

— typhoideum, Acrothecium, Diplodia, and
Fusarium on, in India, 259.

— —, Puccinia penniseti on, in Uganda,
264.

— —, Sphacelia on, in Uganda, 264.

— —, Tolyposporium penicillariae on, in
India, 259.

GENERAL INDEX

Pentalonia nervosa associated with ‘bunchy
top’ of banana in N.S. Wales, 373.

Pepper (Capsicum), see Chilli.

— (Piper nigrum), bacterial disease of,
in Dutch E. Indies, 88.

—, Cephaleuros mycoidea on, in Malaya,
426; in Sarawak, 337.

—, Lampong disease of, in Dutch E.
Indies, 87.

— seedling disease in N. S. Wales,
354,

Peregrinus maidis transmits maize mosaic,
33.

— — transmits sugar-cane mosaic, 381.

Peridermium on pine transmitted by
squirrels, 561.

— acicolum on pines in U.S.A., 348.

— complanatum var. acicola and var. corti-
cola on Pinus longifolia in India, 42.

— elutinum on Abies pectinata in Britain
and Ireland, 430.

— —on Abies balsamea, A. cephalonica,
A. nordmanniana, A. pinsapo, and A,
sibirica in Europe, 431.

— conigenum on pine (? Pinus chihuahuana)
in Arizona and Mexico, 3.

— montanum on pines in U.S.A. pro-
bably distinct from P. acicolum, 349.
— stage of Cronartium ribicola on pine, 3.
Peronospora, biologic specialization in,

485,

— on Chenopodium in Mauritius, 203.

— effusa on spinach in Denmark, 488;
in Texas, 256.

— hyoscyami on tobacco in N.S. Wales,
354.

— parasitica on cabbage in Trinidad, 335.

— pygmaea, water necessary for spore
germination of, 517.

— rubi on raspberry in Germany, 201.

— schachtii on beet in Denmark, 487,
563 ; in Germany, 484; in Holland,
53 overwinters in host tissues, 485 ;
spread of, 484.

— — on mangolds in Germany, 484.

— schleideni on garlic in Spain, 191.

— — on leeks and shallots in Denmark,
488.

— — on onions in Bermuda, 306.

— trifoliorum on clover in Morocco, 54.

— viticola, see Plasmopara viticola.

Persea gratissima, see Avocado pear.

Pestalozzia on coco-nut in Ceylon, 7; in
Dutch E. Indies, 9.

— on dead needles of pine in N. S,
Wales, 299.

— on tea in Ceylon, 7; in Dutch E.
Indies, 9.

— fuscescens var. sacchari on sugar-cane
in the Philippines, 109. .

— guepini on Camellia in Denmark, 488.

— hartigii f. pini-pineae on stone pine in
Italy, 297.

— palmarum, differences between P. theae
and, in Ceylon, 527.

— — on coco-nut in Ceylon, ‘527; in
the Phillippines, 109.

— —on rubber in Malaya, 396.

— theae, differences between P. palmarum
and, in Ceylon, 527.

el

GENERAL INDEX 631

[Pestalozzia theae| on tea in Assam, 344 ;
in Ceylon, 527.

Petroselinum sativum, see Parsley.

Petunia, mosaic disease of, in England,
489, 491.

—, trypanosome-like bodies in phloem
of, 513.

Peucedanum, Protomyces macrosporus on,
242,

Phacidiella discolor on stored apples and
pears in Switzerland, 273.
Phalaris arundinacea, Claviceps purpurea f.
natans Phalaris arundinaceae on, 116.
Pharbitis, Coleosporium ipomoeae on, in
U.S.A , 348.

Phaseolus lunatus, Nematospora phaseoli on,
in Virginia, 194.

— multiflorus, see Bean.

— mungo, leaf curl of, in Dutch E.
Indies, 10.

— radiatus var. aurea, mosaic of, in
Japan, 52.

— vulgaris, see Bean.
Phellinus (Fomes) cryptarum, oak timber
decayed by, in Versailles Palace, 97.
Phloem necrosis of potato, description
of, 569. (See also Potato leaf roll.)
— of mosaic plants, intracellular bodies
in, 227, 513-516.

Phleum pratense, dry spot disease of, in
Norway, 202.

Phlyctaena cinchonae on cinchona in Indo-
China, 96.

Fhoenix, Exosporium preisii and Graphiola
phoenicis on, in Denmark, 488.

— dactylifera, see Date palm.

Pholiota praecox on lavender in France,
225.

Phoma on apple in Ohio, 505 ; in Queens-
land, 123.

— on beet in Bavaria, 510; in U.S.A.,
89; relation of rainfall to, in U.S.A.,

— on coffee beans in Uganda, 408.

— on conifers, notes on species of, 342.

— on Guaiacum officinale in Barbados,
261.

— on potato tubers associated with skin
spot in Germany, 390.

— on Salix alba in Holland, 94.

— apiicola, nutrient requirements of, 83.

— tetae on beet, control in Germany,
224; in Korea, 524; disseminated on
seed, 198, 524; heart rot attributed
to, 466, 484; occurrence in Czecho-
Slovakia, 466; in Denmark, 487 ; in
Germany, 200, 224; in Korea, 524.

— citricarpa on orange in N.S. Wales,

7

— destructiva on tomato, 245; in Norway,
203.

— ferrarisii on tomato in Italy, 91.

— —, Ramularia ferrarisii conidial stage
of, 92.

— glumarum on rice in Uganda, 157.

— hennebergii on wheat synonymous with
Septoria nodorum, 497.

— lingam on cabbage in U.,S.A., 104,
301; rainfall in relation to, 105;
seed treatment for, 104.

[Phoma] macrophoma on orangein S. Aus-
tralia, 292

— musae on Musa textilis in the Philip-
pines, 108.

— — on banana in the Philippines,
108

— napobrassicae on Cruciferae in Den-
mark, 487.

— — on swedes in New Zealand, 98.

— oleracea on brussels sprouts in Hol-
land, 54

— omnivora on citrus in W. Australia,
395.

— panacicola on ginseng in Korea, 503.

— panacis on ginseng in Korea, 503.

— pomi on apple in Ohio, 442, 505.

Phomopsis, similarity of Dothichiza to, 51.

— abietina, suggested identity of Sclero-
phoma pitya with, 342.

— ambigua on pear in Holland. 53.

— californica on citrus in California,
66.

— caribaea on grapefruit from W. Indies,
65.

— citri on citrus, control in U.S.A., 106,
363, 364, 407.

— juniperovora on pine seedlings in
U.S.A., 5.

— mali on apple and pear in California,
393.

— sojae on soy-bean in N. Carolina, 151.

— —, toxicity of sulphur to, 460.

— stewarti on Cosmos in U.S.A., 261.

— —on Guaiacum officinale in Barbados,
261.

Phragmidium potentillae-canadensis, factors
influencing germination of, 179.

Phragmites communis, biology of Claviceps
selerotia on, 115.

Phycomyces nitens, factors influencing
germination of, 464.

Phyllachora eleusines on Eleusine coracana in
Uganda, 264.

— sacchari on sugar-cane in the Philip-
pines, 109,

— trifolii on clover renamed Plowrightia
trifolii, 546.

Phyllosticta brassicicola on cabbage in S.
Australia, 292.

— briardi on apple in Astrakhan, 535.

— cinchonaecola on cinchona in Indo-
China, 95.

— honbaensis on cinchona in Indo-China,
95.

— nicotianae on tobacco in Florida, 474,

— panax on ginseng in Korea, 503,

— sacchari on sugar-cane in Argentina,
340.

— solitaria on apple, control in Illinois,
454; in Indiana, 455; in Ohio, 442,
505 ; in Pennsylvania, 444.

— yersini on cinchona in Indo-China,
95.

Phymatotrichum omnivorum on cotton and
lucerne in Arizona, 501. (See also
Ozonium omnivorum.)

Physalis, cacumber mosaic transmissible
to, 513.

— mosaic in Sumatra, 35; in U.S.A.,
40, 474, 513.

632

[ Physalis], tobacco mosaic transmitted by,
in Florida, 474; in Sumatra, 35.

— heterophylla, overwintering of tomato
mosaic on, in Indiana, 40.

— peruviana, Vermicularia varians on, in
France, 26.

— pubescens, P. subglatrata, and P. vir-
gintiana, overwintering of tomato
mosaic on, in Indiana, 40.

Physalospora cinchonae on cinchona in
Indo-China, 96.

— citricola on citrus in Spain, 405.

— cydoniae on apple, control in Con-
necticut, 220; in Illinois, 454; in
Ohio, 505; in Pennsylvania, 444;
occurrence on apple and pear in
Astrakhan, 535

— —, ‘staling’ of, in cultures, 329.

— salicis on Salix alba in Holland, 94.

Physarum cinereum on sugar-beet in Korea,
524.

Phytamoeba sacchari in Fiji disease of
sugar-cane, 235.

— — (Northiella sacchari) on sugar-cane
in Australia, 579.

Phytobacter lycopersicum on
Astrakhan, 207.

Phytolacca decandra, cucumber
transmissible to, 512.

Phytopathological services
organization of, 478.

Phytophthora, antheridial characters of,
183.

—, apical growth of, 588.

—(?) bud rot of coco-nut in Fiji, 215.

—, list of species of, 183.

— ‘nut-fall’ of coco-nut in Ceylon, 7,
543.

— on Cynometra cauliflora in Ceylon, 7.

— on gooseberry in Holland, 53.

— on Hevea rubber, fuchsine for colour-
ing disinfectants against, in Java,
323; occurrence in Belgian Congo,
577; in Ceylon, 7 ; in Dutch E. Indies,
8, 323; in Malaya, 396; in S. India,
32; in Uganda, 155; parakol fungi-
cide against, in Malaya, 140.

— on lily bulbs in Bermuda, 306.

— on rhubarb in Illinois, 435.

— arecae on areca palm, control in
Mysore, 22, 563.

— cactorum distinct from P. fagi, 435.

— —on apple in U.S.A., 435.

— — on ginseng in Korea, 505; in
US.A., 433.

— — on pear in U.S.A., 433.

— — on rhubarb in Pennsylvania, 433.

— capsici on chilliin New Mexico, 101.

— cinnamomi on Cinnamomum burmanni in
Dutch E. Indies, 9, 246.

— cryptogea on tomato, 245 ; in Denmark,
246 ; in England, 346.

— erythroseptica on potato in Britain,
208, 385; from Dutch E. Indies,
423.

— faberi on cacao in Ceylon, 7; in Gold
Coast, 204; in Guadeloupe, 33; in
San Thomé, 112; in Trinidad, 111;
in W. Indies, 183.

— on coco-nut in Cuba, 268.

tomato in
mosaic

in Italy,

GENERAL INDEX

| (Phytophthora faberi] on papaw in Ceylon,
i

-

— — on rubber in Ceylon, 7; in
Malaya, 396.

— —, oospores of, 183.

— fagi biologically distinct from P.
cactorum, 435.

— infestans on potato, associated with
other organisms in rotting of, 91;
control by heating tubers, 305; occur-
rence in Bermuda, 306; in Britain,
207; in British Columbia, 395; in
Canada, 26, 465 ; in Dutch E. Indies,
422; in France, 174; in Germany,
169, 200 ; in Malta, 535; in Massachu-
setts, 440; in Mauritius, 203; in
Missouri, 573; in Morocco, 54; in
Norway, 202; seed _ certification
against in Canada, 465; tests of new
fungicides against, in Germany, 169;
toxic action of metallic oxides on,
374 ; varietal resistance to, in France,
174; in Germany, 175.

— — on tomato, 245;
246 ; in Virginia, 346.

— meadii erroneously recorded on Cyno-
metra cawiflora in Ceylon, 7.

— — on rubber in S. India, 32.

— melongenae only a variety of P. para-
sitica, 436.

— nicotianae (?) on Ricinus communis in
Sumatra, 296.

— — on tobacco in Dutch E. Indies, 8,
36, 296; (?)in Florida, 476; stable
manure disseminates in Java, 36.

— omnivora on calceolarias, asters, and
gooseberry in Switzerland, 303.

— palmivora morphologically like P.
faberi in W. Indies 185.

— — on coco-nut in W. Indies, 184,
268.

— — oncotton bolls in W. Indies, 185.

— parasitica on citrus in Argentina, 62 ;
in California, 540, 542; in the Philip-
pines, 108.

on tomato, 245; in British
Columbia, 395 ; in England, 346.

— — var. rhei on rhubarb in U.5.A.,
435 ; can infect apple, carrot, parsnip,
potato, tomato, and turnip, 436.

— syringae on apple in Ireland, 182.

— terrestris, see P. parasitica.

Picea, see Spruce.

Picris hieracioides, Protomyces picridis on, 248.

Pigeon pea (Cajanus indicus), Fusarium
udum on, in Uganda, 163.

Pinanga kuhlii, Brachybasidium pinangae on,
341.

Pine (Pinus), Armillaria mellea on, in the
Pyrenees, 431; in S. Australia, 298 ;
in U.S.A., 531.

—, Botrytis on seedlings of, in U.S.A, 5.

—, Caeoma conigenum on, in Arizona and
Mexico, 3.

—, — strobilina on,
Mississippi, 3.

—. Cenangium abietis on, in Switzerland,
246.

—, Ceratostomella on, in U.S.A., 107.

—, — piceae on, in Scotland, 50.

in Denmark,

in Florida and

i i

GENERAL INDEX 633

[Pine], Cladosporium laricis f. pini-pineae on
stone-, in Italy, 297.

—, Coleosporium ipomoeae on, in Florida
and Texas, 348.

—, — ribicola on, in U.S.A., 348.

—, Corticum solani on seedlings of, in
U.S.A., 5.

—, — vagum on, see C. solani.

—, Cronartium conigenum on, in Arizona
and Mexico, 3.

—, — ribicola, disease caused by, on, 3 ;
factors influencing spore germination
of, 516; introduced into U.S.A. on,
from Germany, 143; legislation
against, in Canada, 107, 253, 395 ; in
U.S.A., 4, 483; losses caused by, in
U.S.A., 148; occurrence in British
Columbia, 253, 395; in Europe, 49;
in U.S.A., 4, 107, 205; vitality of
teleutospores of, 4.

—, — strobilinum on, 3.

—, curly-needle disease of, in N. S.
Wales, 299, 354; in S. Australia, 298.

—, damping-off of seedlings of, in
Sweden, 299 ; in U.S.A., 5.

—, Fomes annosus on, in Holland, 430;
in U.S.A., 531.

—, — laricis on, in U.S.A., 531.

—, — pinicola causing decay of felled, in
Oregon, 482.

—, Fusarium on seedlings of, in U.S.A., 5.

—, — culmorum, F. macroxysporum, F.
metachroum, F. cf. redolens, F. cf. sclero-
tioides, F. solani, F. subcarneum, and F.
subulatum on seedlings of, in Sweden,
299, 300.

—, Fusicoccum on, in S. Australia, 298.

—, Lenzites betulina on, in S. Africa, 142.

—, — sdepiaria causing decay of felled,
in Oregon, 482.

—, Melampsora pinitorgua on, in Cyprus,
529.

—, needle blight of stone-, in Italy, 296.

—, Peridermium stage of Cronartium ribi-
cola on, 3.

—, — on, transmitted by squirrels, 561.

—, — acicolum on, in U.S.A., 348.

—, — complanatum var. acicola and var.
corticola on, in the Himalaya, 42.

—, — conigenum on, in Arizona and
Mexico, 3.

—, — montanum on, in U.S.A., proba-
bly distinct from P. acicolum, 849.

—, Festalozzia on dead needles of, in
N.S. Wales, 299.

—, — Murtigii f. pini-pineae on stone-, in
Italy, 297.

—, Phomopsis juniperovora on seedlings of,
in U.S.A., 5.

—. Polyporus anceps causing decay of
felled, in Oregon, 482.

—, — schweinitzii on, in U.S.A., 531.

—, — volvatus on, in U.S.A., 187.

—, Poria subacida on, in U.S.A., 531.

—~, Pythium de Baryanum on seedlings of,
in U.S.A., 5.

—, Rheosporangium aphanidermatus on
seedlings of, in U.S.A., 5.

—, Rhizina undulata on, in the Pyrenees,
431.

[Pine], Rhizoctonia violacea on,in Germany,
201.

—, sap stain and moulds on, in U.S.A.,
185.

—, Sphaeropsis on dead needles of, in
N.S. Wales, 299.

—, Thelephora terrestris (T. laciniata) on, in
S. Australia, 298.

—, Trametes pini on, in the Pyrenees,
431; in U-S.A., 531.

Pine oil (yellow) as a wood preservative,
51.

Pineapple (Ananas satirus), Thielaviopsis
paradoxa from coco-nut can infect, in
Florida, 23.

—, — — on, in the Philippines, 109.

— wilt i in the Philippines, 109.

Pinus spp., see Pine.

Piper nigrum, see Pepper.

Piricularia causing ‘stackburn’ of rice
in U.S.A., 334.

— on Eleusine coracana, Panicum repens, P.
ramosum, P. sanguinale, Setaria italica,
and wheat in India, 259.

— oryzae on rice in India, 258; in
Uganda, 157, 263, 264.

Pisum arvense and P. sativum, see Peas.

Plant disease inspection in Ceylon, 478.

— — services in Italy, 478.

— galls, mechanism of formation of,
494 ; origin and structure of, 377.

— pathology in Crimea, 171; in Den-
mark, 198, 199.

— —, text-book on, 562.

— protection literature, bibliography of,
417,

— quarantine conference in U.S.A., 143.

Plasmodiophora brassicae on cabbage, action
of radium on, 494; control in Ger-
many, 222; in U.S.A., 444; earth-
worms as disseminators of, 351; gall
formation by, 377, 378, 379, 494;
occurrence in Canada, 258; in Den-
mark, 487, 563; in Germany, 223;
in Norway, 203; in Pennsylvania,
444; in Silesia, 351; in Tasmania,
304; in Wisconsin, 258; spreads
from weeds to, in Denmark, 563 ; re-
lation of soil moisture and tempera-
ture to, 258; varietal resistance to,
in Germany, 151, 223, 432, 512.

— — on Capselia bursa-pastoris in Ger-
many, 225.

— — on Cruciferae in Germany, 4382.

— —on mustard in Denmark, 487 ; in
Germany, 432 ; in Norway, 203; tests
with uspulun against, 222.

— —on stocks in Germany, 222.

— — op swedes, varietal resistance to,
in Britain, 151.

— — on turnips in Denmark, 487,

— — on wallflower in Germany, 228.

— humuli on hops in Tasmania, 805,

— vascularum (?) on sugar-cane in Bar-
bados, 468.

Plasmopara halstedii on sunflower in
Japan, 315.

— viticola on vine, control in Algeria,
104; in Austria, 532, 533; in Cyprus,
894; in France, 531; in Germany,

634.

254; in Italy, 326, 562; in Malta,
536; in N. S. Wales, 354 ; in Switzer-
land, 44; critical periods for attack
in Algeria, 104 ; forecasting in Italy,
6; occurrence in Algeria, 104; in
Australia, 292; in Austria, 532, 533;
in Cyprus, 394; in Germany, 201,
254 ; in Italy, 6, 326, 562; in Malta,
536; in Morocco, 54; in N. S. Wales,
354; in S. Australia, 292, 353; in
Switzerland, 302.

Plectodiscella veneta, see Gloeosporium vene-
tum.

Pleosphaeria hesperidum on citrus in Spain,
405.

Pleospora graminea, see P. trichostoma.

— teres on barley in Denmark, 487.
also Helminthosporivm teres).

— trichostoma on barley in Denmark,
487; in Holland, 53. (See also Hel-
minthosporium gramineun).

Pleurostyla, Fomes rimosus on, in S. Africa,
142,

Plowrightia trifolii ascigerous stage of
Polythrincium trifolii, 546.

Plum (Prunus domestica), Bacterium cerasi
on, in California, 393.

—, brown bark spot of, in USA, 221.

—, Cercospora circumscissa on, in Astra-
khan, 535.

—, chlorosis of, in S. Africa, 353.

— Diaporthe perniciosa on, in England,
209.

—, Exoascus pruni on, in Canada, 255;
in Montana, 439; in New Zealand,
373.

—, Ganoderma sessile on, in Argentina, 17.

—, improvements in spraying, in
US.A., 225.

—, Microstroma tonellianum on, in Italy,
166, 167.

—, Polystigmina rubra on, in Astrakhan,
535.

—, Puccinia pruni-spinosae on, in New
Zealand, 320.

—, Sclerotinia cinerea on, in Michigan, 72 ;
in Illinois, 454; tissue changes caused
by, 8.

—, — — f. pruni on, in England, 547.

—, — fructigena on, control of, in Aus-
tralia, 276:

—, Stereum purpureum on, in New Zea-
land, 68; in S. Africa, 451, 452.

Plumeria alba, cats inoculated with
amoebae from latex of, 230.

Poa, Rhizoctonia violacea on, in England,
451.

— annua, biology of Claviceps sclerotia
on, 116.

— nemoralis, biology of Claviceps sclerotia
on, 116.

— pratensis, Septoria resembling S. gra-
minum on, in U.S.A., 357.

— —, — nodorum and S. tritici can in-
fect, 212.

Podocarpus, Fomes geotropus on, in S.
Africa, 142.

Podosphaera leucotricha on apple, control

f
(See

and occurrence in Britain, 209; in .

’ Germany, 120, 131, 201, 220, 223,

GENERAL INDEX

269; in Italy, 294; varietal resis-
tance to, in Germany, 120.

[Podosphaera| oxyacanthae on apple in
Tasmania, 305; probable occurrence
in Italy, 294.

Poison deposited on fruit and vegetables
after spraying in U.S.A., 168.

Polygonum aviculare, Rhizoctonia violacea on,
in England, 451.

Polyosma, Septobasidium bogoriense on, in
Java, 145.

Polyporus anceps on Pinus ponderosa in
Oregon, 482.

— borealis, ash analysis of, 284.

— coffeae on coffee in Uganda, 156, 409.

— fomentarius, see Fomes fomentarius.

— fruticwm on Rubiaceous plants in S$.
Africa, 142.

— igniarius, see Fomes igniarius.

— inzengae, see Fomes fomentarius.

— lucidus on Acacia mollissima in S.
Africa, 142.

— —on Albizzia amara and A. fastigiata
in S. Africa, 142.

— — on Olea laurifolia and O. verrucosa
in S. Africa, 142.

— —on Salix in 8. Africa, 142.

— obliquus on citrus in Spain, 405.

— patouillardii on Scolopia mundtii in S,
Africa, 142.

— ribis on currants in Germany, 201.

— — on gooseberry in Germany, 201.

— sanguineus on Aloe arborescens and A.
marlothii in S, Africa, 142.

— schweinitzii on Douglas fir in U.S.A,
205.

— — on stumps of Douglas fir, larch,
pine, and spruce in U.S.A., 531.

— shoreae on Shorea robusta in Bengal,
350.

— sulphureus on oak in §. Africa, 142.

— versicolor on peach in S. Africa, 142.

— volvatus on Pinus ponderosa in U.S.A.,
187.

— zonalis on cacao in St. Thomas Island,
589.

Polyspora lini on flax in Ireland, 116.

Polystictus abietinus on charred slash wood
in U.S.A., 531.

— — on living and dead wood in
U.S.A., 484.

— biformis, P. cinnabarinus, P. conchifer,
P. floridanus, P. hirsutus, and P. lacteus
on living and dead wood in U.S.A.,
484.

— microloma, ash analysis of, 284.

— occidentalis on coco-nut in St. Thomas
Island, 589.

— pergamenus and P. pinsitus on living
and dead wood in U.S.A., 484.

— sanguineus on coco-nut in St. Thomas
Island, 589.

— versicolor, damage by, often attributed
to Schizophylium commune, 90.

— — on living and dead wood in
U.S.A., 484.

— zonatus on living and dead wood in
U.S.A., 484.

Polystigmina rubra on plum in Astrakhan,
535.

ee

EEE ne

GENERAL INDEX 635

Polythrincium trifolii on clover in France,
544,

— —, Plowrightia trifolii ascigerous stage
of, 546

Pomegranate (Punica granatum), brown
rot of, in N. 8S. Wales, 354.

— Ganoderma sessile on, in Argentina,
17.

Poplar. (Populus), Cytospora chrysosperma
on, in-Canada, 96; in U.S.A., 96,
205.

—, Dothichiza populea on, in Canada, 96.

—, Fomes fomentarius on, in France, 198.

— ot purpureum on, in S, Africa,

Populus tremula, see Aspen.

Poria on rubber in Dutch E. Indies, 8.

— carbonaria on charred slash wood in
U.S.A., 531.

— ferruginosa on cacao in St. Thomas
Island, 589.

— hypobrunnea on rubber in Ceylon, 7.

— selecta on charred slash wood in
U.S.A., 531:

— subacida on pine and spruce in
U.S.A., 531.

— weirii on Thuja plicata in U.S.A., 531.

Potassium permanganate for control of

- Uncinula necator on vine in France,
463.

Potato (Solanum tuberosum), Actinomyces
scabies on, control by green manuring
in Britain, 208, 519; by sulphur in
British Columbia, 519; in Nova
Scotia, 572; in U.S.A., 109; effect of
hydrogen-ion concentration on, 85,
520; manuring experiments against,

' 519; occurrence in Bermuda, 306 ; in
Britain, 138, 208, 519; in British
Columbia, 519; in Canada, 26, 465;
in Dutch E. Indies, 8, 423; in Ne-
braska, 386; in N. S. Wales, 354;
relation of soil temperature to, 137,
520; ‘solbar’ against, 132; toxicity
of sulphur to, 460.

—, Alternaria solani on,in Bermuda, 306,
386; in Canada, 26; in Dutch E.
Indies, 423; in Missouri, 573; in
Morocco, 54; in Nebraska, 386; in
New Jersey, 109.

—, Bacillus amylobacter associated with
rotting of, 91.

—, — atrosepticus on, in Canada, 26, 382,
465 ; in Denmark, 488; in Dutch E.
Indies, 423; in France, resembling
leaf roll, 568; in Germany, 200; in
Manitoba, 424; in Nebraska, 386; in
Norway, 202; revised description of,
85.

—, — solanisaprus, see B. atrosepticus.

—, bacterial ring disease of, in Dutch E.
Indies, 422; in India, 333; in Nor-
way, 202.

—, bacterial rot of, in Canada, 465.

—, Bacterium solanacearum on, in Dutch
E. Indies, 8, 423 ; on stored, in India,
333.

—, black dot disease of, see Vermicularia
varians.

—, black heart of, in Nebraska, 386; re-

lation to temperature and oxygen,
8

[Potato], bright speck disease of, in Den-
mark, 488

—, Chrysophlyctis endobiotica on, see Syn-
chytrium endobioticum.

—, Colletotrichum atramentarium associated
with skin spot of, in Pennsylvania,
390.

—, Corticium solani on, see Rhizoctonia
solani.

—, — tagum on, see Rhizoctonia solant.

— dartrose, see Vermicularia varians.

—, degeneration of, in British Columbia,
519; in Colorado, 289; in France,
288, 518, 568; in U.S.A., 106. (See
also Mosaic, Leaf roll, &c.).

—, Diplodia tubericola on, from Dutch E.
Indies, 423.

— diseases in S. Africa, 386.

—, dry rot of, in Dutch E. Indies, 8,
423.

—, frost necrosis of, in Nebraska, 386.

—, Fusarium on, in Bermuda, 306; in
Canada, 26; in Dutch E. Indies, 423 ;
in Manitoba, 424; in store in India,

—, — caeruleum on, in Norway, 202.

—, — discolor sulphurewm on, in Manitoba,
424,

—, — eumartii on, in Nebraska, 386; in
Pennsylvania, 445.

—, — oxysporum on, control in Oregon,
206 ; factors affecting and methods of
infection, 521; occurrence in Bermu-
da, 306; in Canada, 26, 332, 465; in
Manitoba, 424; in Nebraska, 386, 521 ;
in Oregon, 206 ; in Pennsylvania, 443 ;
in Texas, 256 ; temperature relations
of, 522. :

—, — solani associated with rotting of,
91; occurrence on, in Morocco, 54.
—, — trichothecioides on, in Nebraska,

386.

—, hollow heart of, in Nebraska, 386.

—, internal brown spot of, in Nebraska,
386.

—, ‘ Krauselkrankheit’ of, in Germany,
200.

— leaf roll, certification against, in
Canada, 332, 465; in France, 569;
control in British Columbia, 519;
in Denmark, 291; in France, 519;
in Pennsylvania, 443; description
of, 569; effect of altitude on, in
France, 569; influence of environ-
ment on, in Canada, 519; in Den-
mark, 289; iodine water test for,
569; occurrence in Canada, 26, 255,
332, 424, 465; in Denmark, 289, 487,
563; in Dutch E. Indies, 8, 422; in
France, 174, 288, 518, 568; in Ger-
many, 200; in Holland, 571; in Mani-
toba, 424; in Morocco, 54; in Ne-
braska, 386; in Norway, 202; in
Pennsylvania, 443; in U.S.A., 106,
569; phloem necrosis in, 570; pro-
tozoa in, 227, 513; transmissible to
deadly nightshade in Denmark, 563 ;
transmission of, 175, 291, 569, 571;

636 GENERAL INDEX

varietal resistance to, 84, 174, 175,
255, 288, 488, 518, 571.

[Potato], legislation against diseases of,
jin Bermuda, 307; in Denmark, 199 ; Indies, 423,
in India, 239 ; in Italy, 387; in U.S.A., | —, sclerotial disease (? Sclerotinia liber-
480. tiana) of, in Canada, 27.

— mosaic, amoeboid bodies in, 134; | —, Sclerotinia libertiana on, in Ireland,
certification against, in Canada, 332, 118; in Norway, 202.

465; in France, 569; control by | —, Sclerotium rolfsii on, in U.S.A., 887;
roguing, in British Columbia, 519; parasitic action of, 388, 389. -

in U.S.A., 106; by use of unripe seed | — seed certification in Canada, 253,
tubers in Germany, 519; in Holland, 332, 465 ; in France, 288, 569.

572; factors influencing, 77, 519; in- | — — treatment by heating in Tasmania,
tracellular bodies in phloem of, 513; 305 ; by trypaflavin in Germany, 169;
occurrence in Astrakhan, 535; in by uspulun in Austria, 422; in Ger-
Canada, 26, 332, 424, 465, 519; in many, 510.

Denmark, 487; in Dutch E. Indies, | — —, use of unripe, against mosaic, 519,
422 ; in England, 489, 491 ; in France, 571.

288 ; in Germany, 175, 200 ; in Mani- | — skin spot, relation of, to Oospora pustu-
toba, 424; in Morocco, 54; in Nebra- lans and Spongospora subterranea, 389,
ska, 386; in Norway, 202; in U.S.A., 567.

106; transmissible from cucumber | —, spindling tuber disease of,in U.S.A.,
and possibly to Phyfolacca, 513; trans- 387.

mission of, 175; from wild plants in | —, Spondylocladium atrovirens on, in Cana-
Holland, 571; varietal resistance to, da, 26

in Denmark, 488; in France, 288; in | —, Spongospora subterranea on, in Algeria,
Germany, 175; in Holland, 571; in 568; in Britain, 208; in British
Ontario, 255 ; in U.S.A., 84, 106. Columbia, 395; in Canada, 26, 465;

—, mosaic-like disease of, in Astrakhan, in N.S. Wales, 354; relation to skin
535. spot in Britain and U.S.A., 389, 567;

—, net necrosis of, in Nebraska, transmissible to deadly nightshade in
386. Denmark, 563.

—, new disease of, in Morocco, 86.

—, Oospora pustulans on, in Canada, 26 ;
in England, 390, 567; relation to the
skin spotand powdery scab diseases in
England and U.S.A., 390, 567.

way, 202; in Western U.S.A., 29;
relation of soil temperature to, 136.
[Potato], Rosellinia on, in Dutch E.

.

— ‘sprain’ in Dutch E. Indies, 8, 423.

— spraying, effect on composition and
yield of tubers, 522; on transpiration,
508; second growth of tubers caused
by Bordeaux mixture, 466, 573;

—, phloem necrosis in, 569. stimulatory effect of, 508, 523, 573;

—, Phoma associated with skin spot of, tests in Missouri, 573; in New Jersey,
in Germany,*390. 109.

—, Phytophthora erythroseptica on, from | — streak disease, account of, 285; oc-

Dutch E. Indies, 423; in England,
208, 385.

—, — infestans associated with other

organisms in rotting of, 91; control
by heating tubers, 305; occurrence in
Bermuda, 306; in Britain, 207; in
British Columbia, 395; in Canada,
26, 465; in Dutch E. Indies, 422;
in France, 174; in Germany, 169,
200; in Malta, 535; in Massachusetts,
440; in Mauritius, 203; in Missouri,
573; in Morocco, 54; in Norway,
202; seed certification against, in
Canada, 465 ; tests of new fungicides
against, in Germany, 169; toxic
action of metallic oxides on, 374;
varietal resistance to, in France, 174;
in Germany, 178.

—, Pythium de Baryanum on, in Canada,
26.

—, Rhizoctonia on, in Dutch E. Indies,
423.

—,— solani on, control in British Colum-
bia, 519; in Holland, 572; in Mani-
toba, 386; in U.S.A., 86; effects of,
29, 85; occurrence in British Colum-
bia, 519 ; in Canada, 465; in Germany,
29; in Holland, 53, 572; in Manitoba,
386, 424; in Nebraska, 386; in Nor-

currence in Holland, 53, 285; phloem
necrosis in, 570; synonymy and dis-
tribution of, 285; trypanosome-like
bodies in, 518; varietal resistance to,
84.

—, Synchytrium endobioticum on, con-

tamination of soil by, 575 ; gall forma-
tion by, 494; legislation against, in
Czecho-Slovakia, 422; in Denmark,
421; in England and Wales, 591; in
Germany, 335, 421, 518; in Holland,
421; in Italy, 387; in Norway, 202,
421; in S. Africa, 10 ; life-history of,
574; nature of immunity from, 574;
occurrence in Canada, 26 ; in Czecho-
Slovakia, 422; in England and Wales,
208, 591; in Germany, 30, 200, 421,
517, 575; in Holland, 54, 421; not in
Italy, 387; in Norway, 202, 421; in
S. Africa, 10, 352; in Sweden, 422;
in U.S.A., 143, 443 ; soil sterilization
against, 443; suggested use of X-rays
against, 325; transmissible to deadly
nightshade, 563; varietal immunity
from, tests in France, 174; in Ger-
many, 84, 175, 518, 575; in Scotland,
83, 84; in U.S.A., 84, 443.

— tip burn (physiological) in U.S.A.,
9

-

PE

—————

GENERAL INDEX 637

[Potato] tuber wounds, healing of, 384.

— tubers, rotting of, in Astrakhan,
535.

—, Vermicularia varians on, leaf roll caus-
ed by, 27 ; occurrence in Canada, 26 ;
in France, 27, 173, 334; in S. Austra-
lia, 292.

—, Verticillium on, in Dutch E, Indies,
423 ; in Pennsylvania, 443.

—, — albo-atrum on, in Canada, 332, 465 ;
in Morocco, 54 ; in Oregon, 206 ; from
tomato will infect, 150.

— wart disease, see Synchytrium endobio-
ticum.

‘Pra’ sulphur as a fungicide against
mildew in Germany, 171.

Prickly pear, see Opuntia.

Protoascus colorans causing ‘ yellow grains’
of rice, 334.

Protomycetaceae, specialization of, on
Umbelliferae and Compositae, 242;
systematic position of, 243.

Protomyces crepidicola on Crepis biennis, 243.

— crepidis-paludosae on Crepis paludosa,
243.

— kreuthensis on Aposeris foetida, 243.

— kriegerianus on Leontodon hispidus, 243.

— macrosporus, specialized forms and
hosts of, 242.

— pachydermus on Taraxacum officinale,
243.

— picridis on Picris hieracioides, 243.

Protomycopsis arnoldii on Leontodon autum-
nalis and L, montanus, 248.

— chrysanthemi on Chrysanthemum alpinum,
243.

— leontodontis on Leontodon autumnalis and
L. montanus, 243.

— leucanthemi on Chrysanthemum leucanthe-
mum, 243.

Protozoa, action of latex of plants on,
424, 523.

— in latex, culture and morphology of,
176, 177; mice and cats inoculated
with, 229, 230, 424.

—, inoculations with various, into latex
of Euphorbiaceae, 177.

— in mosaic and allied diseases, 227;
evidence against, 513-516.

Prune (Prunus domestica), Bacillus amylo-
vorus on, 163.

—, brown bark spot of, in U.S.A.,
221.

Prunus americana nigra, Bacillus amylovorus
on, in U.S.A., 163.

— amygéalus, see Almond.

— armeniaca, see Apricot.

— cerasus, see Cherry.

— chamaecerasus, Exouscus minor on, in
Germany, 373.

— domestica, see Plum and Prune.

— itokasura, Mycosphaerella cerasella ba in
Japan, 416.

— mume, resistant to crown gall in n Cali-
fornia, 394,

— persica, see Nectarine and Peach,

— triloba var. plena, Bacillus amylovorus on,
in U.S.A., 164.

—, varietal resistance of, to Bacterium
tumefaciens, in California, 394.

[Prunus] yamasakura, Mycosphaerella cera-
sella on, in Japan, 416.

Pseudococcus citri, control of, by Entomo-
phthora fumosa in Florida, 311.

—— — on coffee associated with Polyporus
coffeae in Uganda, 156.

Pseudomonas alboprecipitans on Chaetochloa
lutescens in Arkansas, 447; can infect
barley, maize, oats, rye, Sudan grass,
and wheat, 447.

— campestris on Brassica spp. in Norway,
203.

— — on cabbage, kohlrabi, kale, turnip,
and other Cruciferae in Bermuda, 306.

— citri on citrus, eradication in S. Africa,
352; in U.S.A., 106 ; introduced into
U.S.A. on Japanese orange, 143; not
known in Italy, 404; occurrence in
Mauritius, 203; in the Philippines,
108; in S. Africa, 352; in U.S.A.,
106 ; relation of age of host to infection
by, 63 : relation of stomata to infection
‘by, 62 ‘ varietal resistance to, 63.

— destructans on sugar-beet in Korea,
524,

— — (?) on white turnip in Wales, 196.

— dissolvens on maize in Arkansas, 158.

— juglandis on walnut in S. Australia,
292.

— musae in relation to Panama disease
of banana, 217.

— phaseoli on beans in Bermuda, 306 ;
in Norway, 203; in the Philippines,
445,

— pruni on peach in U.S.A., 219.

— savastanoi on olive in Italy, 415; in
U.S.A., 12; can infeet Adelia, Chion-
anthus, Fraxinvus, Jasminum, Ligustrum,
and Osmanthus, 12; structure of galls
caused by, 377.

Pseudoperonospora cubensis on cucumber in
Germany, 201 ; in Massachusetts, 440,

— — on melon in Massachusetts, 440.

— — on watermelon in U.S.A., 280.

Pseudopeziza ribis on currants in Switzer-
land, 277.

— — on gooseberry in S. Australia, 353.

— tracheiphila on vine in Austria, 532,
533; in Germany, 201; in Switzer-
land, 302.

Pseudotsuga taxifolia, Armillaria mellea on,
in U.S.A., 531.

— —, Fomes luaricis on, in U.S.A., 205,
531.

— —, — roseus on, in U.S.A., 205, 531.

— —, Polyporus schweinitzii on, in U.S.A.,
205, 531.

— —, Trametes pini on, in U.S.A., 107,
205, 531.

Psidium guajava, see Guava.

Psorosis of citrus in California, 542.

— of orange in the Philippines, 108.

Ptaeroxylon utile, Fomes rimosus on, in 8.
Africa, 142.

— —, Trametes incondita on, in 8S. Africa,
142.

Puccinia andropogoni, germination of
teleutospores of, in Missouri, 179.

--apii, controlled by uspulun in Ger-
many. 20.

Pa
638

[Puccinia] arachidis on groundnut, danger
of importing into Africa, 351.

— asparagi, germination of teleutospores

of, in Missouri, 179.

— coronata, see P. lolii.

— dispersa on rye in Austria, 588; in
Canada, 303.

— glumarum, influence of excessive nitro-
genous manuring on, 162.

— —on Agropyron, Bromus, Elymus, and
Sitanion in California, 392.

— — on wheat, genetics of resistance to,
57; influence of climate on, 361;
occurrence in Austria, 538 ; in France,
361; in India, 307; not in Uganda,
263 ; varietal resistance to, in India,
307.

— graminis on barberry in Australia,
307; in Canada, 303; in Denmark,
199, 487 ; in Europe, 499.

— — on oats, genetics of resistance to,
in U.S.A., 210 ; occurrence in Canada,
303.

— — on oats and rye spreads from
grasses in Denmark, 563.

— —onrye in France, 362.

— — on rye and wheat hybrid in .

France, 362.

— — on wheat, barberry eradication
against, in Denmark, 199, 487, 499;
in U.S.A., 106, 399, 439 ; in Western
Europe, 499; biologic forms of, in
Canada, 253, 358; in U.S.A., 158;
cytology of resistance to, 359, 401; hy-
drogen-ion concentration in relation to

resistance to, 13, 361; influence of |

climate on, 361; losses caused by, in
Denmark, 199; occurrence in Astra-
khan, 207; in Australia, 307; in

Canada, 253, 303, 357; in Denmark, |
199; in France, 361; in India, 307; »
in Uganda, 264; in U.S.A., 106, 112, |

158, 489; temperature relations of,
13; varietal resistance to, in India,
307 ; in Morocco, 54; in U.S.A., 106,
112, 158, 392 ; viability of spores of, 14.

— helianthi, germination of teleutospores
of, in Missouri, 179.

— —on sunflower in Canada, 304.

— kuehnii on sugar-cane in Australia,
580 ; in the Philippines, 109.

— lolii, biologie specialization of, in
America, 209.

— — on Calamagrostis canadensis, alter-
nate hosts of, in U.S.A., 209.

— — on oats, alternate hosts of, in
U.S.A., 209; biologic specialization
of, in U.S.A., 209; legislation against
in Canada, 528 ; occurrence in Britain,
208; in Canada, 255, 303, 528; in
Wales, 401.

— —on Rhamnus alnifolia, R. californica,
and R. caroliniana, in U.S.A., 209.

— — on Rhamnus cathartica in Britain,
208 ; in Canada, 303, 528 ; in U.S.A.,
209.

— — on Rhamnus frangula, R. lanceolata,
and R. purshiana in U.S.A., 209.

— malvacearum, factors influencing spore
germination of, 516.

GENERAL INDEX

[ Puccinia] maydis, germination of teleuto-
spores of, in Missouri, 179.

— — on maize in Uganda, 264.

— menthae var. americana, germination of
teleutospores of, in Missouri, 179.

— penniseti on Pennisetum typhoideum in
Uganda, 264.

— peridermiospora, germination of teleuto-
spores of, in Missouri, 179.

— pittieriana on tomato, 245.

— pringsheimiana on Carex in Denmark,
563.

— pruni-spinosae on almond, anemone,
apricot, and nectarine in New Zealand,
320.

— — on peach in Bermuda, 306; in
New Zealand, 320.

— — on plum in New Zealand, 320.

— ruelliae, germination of teleutospores
of, in Missouri, 179.

— semibarbatae on Bulbine semibarbata in
S. Australia, 292.

— sorghi, see P. maydis.

— subnitens on Distichlis spicata and
spinach in U.S.A., 100.

— sydowiana, germination of teleuto-
spores of, in Missouri, 179.

— triticina on wheat, infiuence of climate
on, 861; occurrence in Austria, 538 ;
in Canada, 254, 303; in France, 361 ;
in India, 307 ; in Uganda, 156, 264 ;
varietal resistance to, in India, 307;
in U.S.A., 118, 392.

— windsoriae, germination of teleuto-
spores of, in Missouri, 179.

Pucciniopsis caricae on papaw in Bermuda,
306.

Punica granatum, see Pomegranate.

Pyrethrum cinerariaefolium, Sclerotinia liber-
tiana on, in France, 103.

Pyronema, apical growth of hyphae of,
588.

Pyrus calleryana resistant to Bacillus
amylovorus in U.S.A., 275.

— communis, see Pear.

— coronaria, Bacillus amylovorus on, in
U.S.A., 163.

— malus, see Apple.

— serotina resistant to Bacillus amylovorus
in U.S.A., 274.

— sinensis, Gymnosporangium asiaticum on,
in Japan, 237.

— —, — shiraianum on, in Japan, 238.

— —, Roestelia koreaensis on, in Japan,
237. ‘

— spectabilis, Gymnosporangium yamadae
on, in Japan, 237.

— toringo, Gymnosporangium asiaticum on,

in Japan, 237.

— —, — yamadae on, in Japan, 237.

— ussuriensis resistant to Bacillus amylo-
vorus in U.S.A., 125, 274.

— zumi, Gymnosporangium hemisphaericum
on, in Japan, 238.

Pythiacystis citrophthora on citrus in Cali-
fornia, 539, 542; temperature relations
of, 542; varietal resistance to, 540.

— — on orange in S. Australia, 309.

— — on stone fruit in California, 393.

Pythium on celery in Bermuda, 306.

-

GENERAL INDEX

[Pythium] on lettuce in Bermuda, 306.

— on roots of various plants in Italy,
283.

— on tobacco in Sumatra, 296,

— de Baryanum on beet in Denmark,
487; in Germany, 200, 224,

— — on cabbage spread from weeds in
Denmark, 563.

— — on Pelargonium in Holland, 54.

— on pine seedlings in U.S.A, 5.

— on potato in Canada, 26.

— on seedlings in Norway, 203.

— on tomato, 245.

Quercus, see Oak.
— wislezenii, Bacterium
in California, 393.
Quince (Cydonia vulgaris), Bacillus amylo-
vorus on, in U.S,A., 125, 163.

—, LEntomosporiwum maculatum on,
Fabraea maculata.

—, Fabraea maculata on, in S. Africa, 71;
in Switzerland, 275, 302.

—, Gymnosporangium asiaticum on,
Japan, 237.

—, Oidium cydoniae on, in Switzerland,
302.

—, Penicilliwm crustaceum on stored, in
Italy, 167, 168.

—, Sclerotinia linhartiana on, in Switzer-
land, 302.

citriputeale on,
see

in

Radish (Raphanus sativus), stimulatory
effect of Bordeaux mixture on, 507.
Radium, action of, on neoplasias of

plants, 493.

—, failure of, to control cereal smuts,
324,

Ragmus flavomaculatus and R. morosus in
relation to bacterial infection of cotton
bolls in S. India, 367.

Ramularia on elms in Holland, 2.

— ferrarisii probably conidial stage of
Phoma ferrarisii on tomato in Italy, 92.

Raphanus sativus, see Radish.

Raspberry, Gloeosporium venetum on, in
Illinois, 219 ; in Washington, 278.
—, black (Rubus occidentalis), Bacteriwm

tumefaciens on, in Illinois, 218.

—, —, eastern blue-stem of, in U.S.A.,
128, 219, 352.

—, —, Gloeosporium venetum on, in Illinois,
219, 454; in Washington, 278; in
Wisconsin, 258, 493.

—,—, leaf curl of, in Canada, 17, 253,
BAT s in U.S.A., 17, 129 ; transmission
of, by Aphis rubiphila, 548.

—, —, mosaic of, in Canada, 17, 253,
547; in U.S.A, 17, 129, 352; trans-
mission of, probably by Aphis rubiphila,
548.

, —, western blue-stem of, in New
York, 352.

—, red (Rubus idaeus), Armillaria mellea
on, in U.S.A., 278.

—,—, Bacterium tumefaciens on, in U.S.A.,
218, 278, 493.

—, —, Coniothyrium fuckelii on, in Ger-
many, 201; in Holland, 53.

639

mark, 488; in Germany, 128, 201,
457 ; in Switzerland, 278, 302.

[Raspberry, red], Fusarium on, in Hol-
land, 53.

, leaf curl of, in Canada, 17, 253,
547 ; aU SvAr eno! transmission
of, by Aphis rubiphila, 548,

—, —, mosaic of, in Canada, 17, 253,
547; in U.S.A, 17, 129, 351, 546;
transmission of, probably by Aphis
rubiphila, 548.

» —, Mycosphaerella
Washington, 278.
—, —, Peronospora rubi on, in Germany,

201.

— yellows, see Leaf curl and Mosaic.

Rhamnus alnifolia, R. californica, and R.
caroliniana, Puccinia lolii on, in U.S.A.,
209.

— cathartica, Puccinia lolii on, legislation
against, in Canada, 528; occurrence
in Britain, 108; in Canada, 303; in
U.S.A., 209.

— —, Torula ligniperda on, in Europe, 34.

— frangula, R. lanceolata, and R. purshiuna,
Puccinia lolii on, in U.S.A., 209.

Rheosporangium aphanidermatus on pine
seedlings in U.S.A., 5.

Rheum, see Rhubarb.

Rhizina undulata on Pinus maritima in the
Pyrenees, 451.°

Rhizoctonia, apical growth of hyphae of,

rubina on, in

— on bean, cabbage, and tcmato in
Trinidad, 335.

— on potato in Dutch E. Indies, 423.

— on sugar-beet in Korea, 524.

— ferrugena on Andropogon sorghum sac-
charatus in Barbados, 261.

— grisea on sugar-cane in Barbados, 261.

— pallida on sugar-cane in Barbados,
261, 467.

— (?) solani in mycorrhiza, 283.

— solani, nutrient requirements of, 83.

— — on cotton in Arizona, 154,

— — on potato, control in British
Columbia, 519; in Holland, 572; in
Manitoba, 386 ; in U.S.A., 86; effects
of, 29, 85; occurrence in British
Columbia, 519; in Canada, 465; in
Germany, 29; in Holland, 53, 572;
in Manitoba, 386, 424; in Nebraska,
386; in Norway, 202; in Western
U.S.A., 29; relation of soil tempera-
ture to, 156,

—— on sugar-cane in Barbados, 260, 467.

— — on tomato in Denmark, 246; in
Norway, 203.

— —, physiology of, 419, 470, 471.

— —, relations between, and Hypochnus
solani, 471; and Macrophoma corchori,
260 ; and Moniliopsis aderholdi, 470.

— —, soil temperature relations of, in
U.S.A., 186.

— violacea on beet in Czecho-Slovakia,
467 ; in Holland, 53.

— — on citrus in Spain, 405.

— —on clover (red) in England, 450,

— —on lucerne in France, 371.

» —, Didymella applanata on, in Den- | — — on Mentha arvensis in England, 451.

640

[Rhizoctonia violacea] on pine in Germany,
201.

— —on Poa and Polygonum aviculare in
England, 451.

— — on Veronica agrestis in England,
451.

Rhizopus, apical growth of hyphae of,
588.

— arrhizus and R. artocarpi, temperature
relations of, 564.

— chinensis, R. delemar, R. maidis, and
R. microsporus, pectinase production
by, 464; rotting of sweet potato by,
464; temperature relations of, 464,
565.

— nigricans on cotton in Egypt, 449.

— — on tomato, 245.

— —, factors influencing spore germina-
tion of, 516; influence of CO, and
temperature on, 25; of temperature
on amylase in spores of, 419 ; nutrient
requirements of, 82; rotting of sweet
potato by, 418, 464, 565; temperature
relations of, 464, 565.

— nodosus, oryzae, and reflexus, pectinase
production by, 464; rotting of sweet
potato by, 464 ; temperature relations
of, 464, 565.

— tritici, influence of temperature on
amylase in spores of, 419; pectinase
production by, 464; rotting of sweet
potato by, 464 ; temperature relations
of, 464, 565.

Rhizosphaera kalkhofjii,
identical with, 342.

Rhubarb (Rheum), Phytophthora on, in
Illinois, 435.

—, — cactorum on, in Pennsylvania,
433.

—, — parasitica var, rhei on, in US.A.,
435.

Rhus laevigata, Fomes rimosus on, in S.
Africa, 142.

Rhynchosporium secalis on barley in Cali-
fornia, 392; in Canada, 304; varietal
resistance to, 392.

Rhytisma acerinum on maple in U.S.A.,
481.

Ribes, Cronartium ribicola on species of, in
Canada, 304; in Switzerland, 483; in
U.S.A, 3, 107, 205.

— alpinum, Cronartium ribicola can infect,
483.

— americana, Cronartium ribicola on, in
USS.A., 4.

— cynosbati, Cronartium ribicola on, in
U.S.A., 4.

— gordonianum, Cronartium ribicola can in-
fect, 483.

— grossularia, see Gooseberry.

— nigrum, R. rubrum, see Currants.

— odoratum, Cronartium ribicola on, in
U.S.A., 4.

— petraeum, Cronaitium ribicola can infect,
483.

— rotundifolium, Cronartium ribicola on, in
US.A., 4.

— sanguineum, Cronartium ribicola can in-
fect, 483.

— uva crispa, Cronartium ribicola on, 483.

Sclerophoma pini

GENERAL INDEX

Rice (Oryza sativa), Alternaria on, in
USS.A., 335.

— brusone,
India, 32.

—, Cephalosporium on, in India, 259.

—, LEpicoccum hyalopes on, in Uganda,
157.

—, Fusarium roseum on, in Uganda, 157.

—, Gibberella saubinetii on, in Uganda,
157.

Bek: alot stilboideum on, in Uganda,

ol.

—, Helminthosporium on, in India, 139 ;
in U.S.A., 334.

—, — macrocarpum on, 230.

—, — maculans on, 230.

—, — oryzae on, in Dutch E. Indies, 8;
in Japan, 139, 230; in Uganda, 157;
susceptibility of other cereals and
grasses to, in Japan, 231; tempera-
ture reiations of, 232.

—, — sigmoideum on, 230.

—, Leptosphaeria michotii on, in Uganda,

disease resembling, in

—, Melanospora zamiae on, in Uganda,
157.

—. Phoma glumarum on, in Uganda,

—, Piricularia on, in U.S.A.. 334.

—, — oryzae on, in India, 258; in
Uganda, 157, 263.

—, Protoascus colorans causing
grains of, 334.

—, root rot of, in Dutch E. Indies, 8.

—, sclerotial disease of, in India, 259.

—, ‘stack-burn’ of, in U.S.A., 334.

— ‘straighthead’ of, in India, 31.

Ricinus communis, Bacterium tumefaciens
causing fasciation of, 10.

— —, Phytophthora nicotianae (?) on, in
Sumatra, 296.

Robinia pseud-acacia, Fomes rimosus on, in
Michigan, 189.

— —, Ganoderma sessile on, in Argentina,
17.

— —, slime bodies in phloem of, 515.

— —, Trametes robiniophila on, in Michi-
gan, 189.

Roesleria hypogaea on pear in Holland, 53.

Roestelia koreaensis on Japanese sand pear
(Pyrus sinensis), 237.

Rome convention of 1914, application of,
LOW.

‘Roncet’ disease of the vine in Malta,
536.

Rose (Rosa), Bacterium tumefaciens on,
production of varieties resistant to,
356.

—, fungicidal injury to, in Denmark,
488.

—, Sphaerotheca pannosa on, control in
Germany, 131, 171; by soft soap in
Sweden, 458.

—, wet root rot fungus on, in Uganda,
157.

Rosellinia on cinchona
Indies, 9.

— on potato in Dutch E. Indies, 423.

— on tea in Dutch E. Indies, 9.

— arcuata on tea in India, 343.

yellow

in Duteh E.

GENERAL INDEX

ie sellinia] bunodes on cacao in Trinidad,
a4.

— caryae on hickory in U.S.A., 50.

— pepo on cacao in Trinidad, 111.

Rosette of wheat in U.S.A., 106.

‘Rotbrenner’, see Pabictopesce trachei-
phila.

Rubber, Para (Herea brasiliensis), brown
bast of, effect of tapping on, 8, 155,
178, 233, 396 ; etiology of, 232; oceur-
rence in Belgian Congo, B77 : in
Dutch E. Indies, 8; in India, 32;
Malaya, 232, 396, 425; in Uganda,
155 ; relation of bacteria to, 232; of
yield to, 233; studies on, 178, 282,
425,

—,—, brown root disease of, in Malaya,
291, 396. (See also Fomes lamavensis).

—, —, Cephaleuros mycoidea on, in Malaya,

ie Corticium (?) on roots of, in Malaya,

, —, Corticium salmonicolor on, in Dutch
E. Indies, 8; in Malaya, 396.

—, —, die-back of, in Dutch E. Indies, 8.

—, —, Diplodia on, in Malaya, 396.

—.—, Fomes on, in Dutch E. Indies, 8.

—.—, — lamaoensis on, in Ceylon, 7,
291.

—,—, — lignosus on, in Ceylon, 7, 374;
os Malaya, 396; toxicity of lime to,

74.

—. —, — pseudoferreus on, in Dutch E.
Indies, 8 ; in Malaya, 396.

—, —, Helminthosporium on, in Malaya,
396.

—, —, Hymenochaete on, in Ceylon, 291.

—, —, Hypochnus on, in Dutch E.
Indies, 8.
—, Kretzschmaria micropus on, in
~ Malaya, 32.
—. —, ‘kringrot’ of, in Dutch E.
Indies, 8.
—. —, legislation regarding importation

of, in Malaya, 238 ; in India, 240.

—, —, Melanopsammopsis ulei on leaves of,
in British Guiana, 354.

—,—, mould preventives on sheet, 139,
427, 578.

—,—, Mucor on, in Maiaya, 396.

—, —, Oidium on, in Dutch E. Indies, 8 ;
in Uganda, 155, 156.

—, —, Pestalozzia palmar um on, in Malaya,
396.

—, —, Phytophthora on, fuchsine for

colouring disinfectants against, in
Java, 323; occurrence in Belgian
Congo, 577; in Ceylon, 7; in Dutch
E. Indies, 8, 323; in India, 32; in
Malaya, 396; in Uganda, 155; para-
kol as a fungicide against, 140.

—,—-—, /faberi on, in Ceylon, 7; in
Malaya, 396.
—, —, — meadii on, in India, 32,

—-,-, ’ Poria on, in Dutch E. Indies, 8.
—, —, — hypobrunnea on, in Ceylon, 7.
—, —, Sphaeronema on, in Dutch E.
oo 8.
—, — _Jfimbriatum on, in Belgian
~ Song, 577; in Malaya, 396, 426,

641

[Rubber, Para], Sphaerostilbe repens on, in
Malaya, 396.

—, —, tests of new disinfectants for, in
Malaya, 140.
—, —, thread blight of, in Malaya, 396.
—, —, Ustulina zonata on, in Ceylon, 7;
in Kenya, 260 ; in Malaya, 32, 396.
—, —, Xylaria thwaitesii on, in Ceylon,
576.

Rubiaceae, bacterial nitrogen fixation in
leaves of, 418.

—, Polyporus fruticum on, in S. Africa, 142.

Rubus caesius, see Dewberry.

— fruticosus, see Blackberry.

— idaeus, see Raspberry (red).

— occidentalis, see Raspberry (black).

— phoenicolasius, leaf curl of, 129; in
Canada and U.S.A., 17.

— strigosus, leaf curl of, in Canada and
UES FAS LT,

Rush, see Juncus.

‘ Rustikol’ as a disinfectant for rubber,
140.

_ Rye (Secale cereale), bright speck disease

of, in Denmark, 488.

—, Claviceps purpurea on, controlled by
formalin and salt, 498 ; cultivation of,
in Austria, 114, 400; dissemination of
sclerotia of, 115.

—, Fusarium on, in Holland, 53; in
Bavaria, 281, 509.

—, — virale on, control, in Germany,
161, 200, 417, 511; in Norway, 202.
— mycorrhiza of, in Italy, 172.

—, Pseudomonas alboprecipitans can infect,
447.

—, Puccinia dispersa on, in Austria, 538 ;
in Canada, 303.

—, — graminis on, in Denmark, 568 ; in
France, 362.

— seed disinfection tests in Germany,
511; in Norway, 202.

—, Septoria nodorum and S. tritici can in-
fect, 212.

—, — secalis on, in U.S.A., 356,

—, soil acidity disease of, in Germany,
200 ; importance of lime in control of,
499, 500.

—, Urocystis occulta on, control of, in Ger-
many, 170, 417; in Sweden, 19;
occurrence in Denmark, 487.

Saccharum officinarum, see Sugar-cane.

— narenga, sugar-cane mosaic on, in
U.S.A., 584,

Saffron (Crocus sativus), Bacillus croci on,
in Japan, 427.

Salix, Polyporus lucidus on, in 8, Africa,
142.

— alba var. vitellina pendula, Aposphaeria
pulviscula on, in Holland, 94.

— — —, Discella carbonacea on, in Hol-
land, 94.

— — —, Fusicladium saliciperdum on, in
Holland, 93.

— — —, Phoma intricans on, in Holland,
94,

— — —, Physalospora salicis on, in Hol-
land, 94,

Saltation in Helminthosporium, 60,

642 GENERAL INDEX

Sambucus nigra, see Elderberry.

Sandal (Santalum album), spike disease
of, transmission by grafting and
haustoria, 380.

‘Sand drown’, chlorosis of maize and
tobacco in U.S.A., 81, 421.

Santalum album, see Sandal.

Sap-stain of timber, control in U.S.A.,
185.

Sasa spiculosa, Epichloe sasae on, in Japan,
238.

Schinus dependens, Trametes trogii on, in
France, 300.

— moille, Inonotus schini on, in U.S.A., 49.

Schizophyllum commune, biology of; in S.
Africa, 271; parasitism of, on fruit
trees in S, Africa, 272; in U.S.A., 90.

Schotia latifolia, Fomes rimosus on, in S.
Africa, 142.

Sclerophoma piceae identical with S. pityo-
phila, 342.

— pini identical
kalkhoffii, 342.

— pitya identical with S. pi/yophila and
possibly with Phomopsis abietina, 342.
— pityella identical with S. pityophila,

342.

— pityophila on conifers, 342.

Sclerospora on maize in Uganda, 156, 264.

— on sorghum in Uganda, 157, 264.

— graminicola on Sudan grass in S&S.
Africa, 10.

— javanica on maize in Dutch E. Indies,

with Rhizosphaera

— philippinensis on maize, dissemination
of, in the Philippines, 359.

— sacchari on sugar-cane in Australia,
579; in the Philippines, 109.

— spontanea on maize, dissemination of,
in the Philippines, 359.

— —on sugar-cane in the Philippines,
360.

Sclerotinia on ginseng in Korea, 508.

— on cabbage in Bermuda, 306.

— on cucumber in California, 152.

— cinerea, apothecia of, in New Zealand,
275. ;

— —on cherry, control in Illinois, 454.

— — on fruit in New Zealand, 165, 275,
321,

— — on peach, control in Australia,
69 ; in Illinois, 454 ; in Michigan, 72;
in New Jersey, 506; in New Zealand,
275.

— — on plum, biochemistry of, 81;
control in Illinois, 454; in Michigan,
72.

— —, toxicity of sulphur to, 460.

— — f. mali on apple in England, 547.

— — f. pruni on cherry and plum in
England, 547.

— fructigena, apothecia of, in N. S.
Wales, 120.

— —, factors influencing spore germina-
tion of, 516.

— —onapple in N.S. Wales, 120.

— — on apricot in N. S. Wales, 120.

— — on cherry, control in Australia,
276 ; occurrence in Crimea, 172.

— on loquat in N.S. Wales, 120.

[Sclerotinia fructigena| on peach, control in
Australia, 276 ; in Connecticut, 220.
— — on plum, control in Australia,

276.

— — on stone fruit in N. S. Wales, 353.

— fuckeliana on vine in New Zealand,
534.

— libertiana on beans in Bermuda, 306.

— — on carrot in Pennsylvania, 444.

— — on celery in New Jersey, 102; in
Pennsylvania, 444.

— —on chicory in the Pyrenees, 193.

— —on citrus in California, 541, 542.

— — on flax in Ireland, 118.

— — on lettuce in Bermuda, 306; in
France, 102, 193; in U.S.A., 102, 444.

— —on melon in France, 102.

— —on potato in Canada, 26, (?) 28 ; in
Ireland, 118; in Norway, 202.

— — on Pyrethrum cinerariaefolium in
France, 103.

— — (?)on sunflower in Canada, 304 ;
in Holland, 544; in Montana, 439,
544,

— — on tomato in Canada(?), 28; in
Germany, 201.

— linhartiana on quince in Switzerland,
302.

— minor on lettuce in New Jersey, 102.

— sclerotiorum on peas in Denmark,
487.

— — on tomato in Denmark, 246. (See
also S. libertiana).

— trifoliorum on clover in British Colum-
bia, 395; in England, 450; varietal
susceptibility to, 512.

Sclerotivm on apple in S. Africa, 110.

— on sugar-cane in the Philippines,
109.

— cepivorum on garlic in Spain, 191; re-
lation of, to Botrytis cana and Sphacelia
allii, 191.

— griseum, see Rhizoctonia grisea.

— rolfsii, hosts of, in N. S. Wales, 354.

— —on Hibiscus cannabinus in Sumatra,
315.

— — on Mimosa invisa in Sumatra, 295.

— —on potato in U.S.A., 387 ; parasitic
action of, 388, 389.

— — on sugar-beet in Korea, 524.

— — on sugar-cane in Cuba, 525; in
the Philippines, 109.

— — on tobacco in the Philippines,
109; in Sumatra, 314.

— — on tomato in Denmark, 246.

— — on watermelon, control in U.S.A.,
280.

— sefosum on tomato in England, 347,
489.

Scolopia munatii, Fumes rimosus on, in S.
Africa, 142.

— —., Polyporus patouillardii on, in S..

Africa, 142.

Seolytus beetles in relation to elm
disease in France, 484.

Secale cereale, see Rye.

— montanum, Claviceps purpurea on hy-
brids of rye and, in Austria, 400.

Seed certification in Canada, 253, 332,
465; in France, 288, 569.

GENERAL INDEX

[Seed] disinfection apparatus in Ger-
many, 224.

Selinum, Protomyces macrosporus on, 242.

Senecio vulgaris, Thielavia basicola on, in
Ireland, 117.

Septobasidium bogoriense, morphology of,
145 ;
chona, Citrus, Coffea, Erythrina, Fraxinus.
Manihot, Marsdenia, Morus, Paritium,
Polyosma, Solanum, Stachy‘arpheta, and
Thea in Java, 145.

— mompa on sugar-beet in Korea, 524.

Septogloeum arachidis, see Cercospora per-
sonata.

Septoria on Poa pratensis in U.S.A.. 357.

—_ er on Agropyron repens in U.S.A.,
356.

— apii on celery, control in Canada,
255 ; disseminated on seed, 198; oc-
currence in Morocco, 54.

— avenae (Leptosphaeria avenaria) on oats
in Wisconsin, 159.

— bromi on brome grass in Italy and
U.S.A., 356.

— depressa on orange in S. Australia,
292,

— glumarum, see S. nodorum.

— graminum on oats and wheat in Mo-
roceo, 54.
— — var. ¢,
avenae, 159.
— lycopersici on tomato, control in Ber-
muda, 307; in U.S.A., 346, 443; oc-
currence in Denmark, 246; in Ger-

many, 201; in S. Australia, 292.

— nodorum can infect Poa pratensis and
rye, 212.

— — on wheat in Arkansas, 497; in
Canada, 304; in U.S.A., 211; suppos-
ed perithecial stage of, 212.

— passerini on barley in Italy and U.S.A.,
356.

— petroselini var. apii on celery in Ber-
muda, 306.

— piricola on pear in Astrakhan, 535.

— secalis on rye in U.S.A., 356.

— tritici can infect Poa pratensis and rye,
212.

— — on wheat, distinct from S. grami-
num, 212; from S. nodorum, 497; oc-
currence in U.S.A., 212.

Sequoia sempervirens, bacterial tumours of,
in France, 95.

Sereh disease of sugar-cane, control by
hot water in Java, 468; disease re-
sembling, in the Philippines, 109;
occurrence in Java, 8; in Singapore,
469,

Service berry, see Amelanchier canadensis.

Sesleria coerulea, biology of Claviceps sclero-
tia on, 115.

Setaria glauca, Helminthosporium oryzae can
infect, in Japan, 231.

— italica, Cladosporium on, in Ceylon, 7.

— —, Helminthosporium foot rot of wheat
can infect, 60.

— —, — on, in U.S.A., 61.

— —, — oryzae can infect, in Japan,
231.

— —, Piriculavia on, in India, 259.

avenue distinct from S.

occurrence on Calosanthes, Cin- |

643

Shallot (Allium ascalonicum), Peronospora
schleideni on, in Denmark, 488.

Shingles, asphalt, destroyed by Basidio-
mycete resembling Merulius lacrynians,
187.

Shorea robusta, Polyporus shoreae on, in
Bengal, 350.

Silver leaf disease, see Stereum purpureum.

Sisal (Agave cantula), Colletotrichum agaves
on, in the Philippines, 108.

Sitanion, Puccinia glumarum on, in Cali-
fornia, 392.

Sizygium, Fomes senex on, in S. Africa,
142.

Slime bodies in relation to protozoa in
virus diseases of plants, 514, 515.

— disease, see Bacillus solanacearum.

Smerinthus populi, Cordyceps militaris on
larvae of, in Sweden, 76.

Smoke injury acting through soil altera-
tions, 20; promoting infection by
Fomes annosus, 482.

Snapdragon, see Antirrhinum.

Snowdrop (Galanthus nivalis),
galanthi on, in Germany, 449.

Sodium silicofluoride for prevention of
moulds on sheet rubber, 139, 427,
01d.

Soil acidity disease of cereals in Ger-
many, 200, 499.

— fungi, a synthetic medium for the
estimation of, 233.

Solanum, mosaic disease of, in Sumatra,
35.

—, Septobasidium bogoriense on, in Java,
145.

— carolinense, overwintering of tomato
mosaic on, in Indiana, 40; tobacco
mosaic on, in Florida, 474.

— dulcamara, tomato mosaic transmis-
sible to, 491.

— integrifolium, tomato mosaic trans-
missible to, in Indiana, 40.

— meiongena, see Eggplant.

— nigrum, mosaic disease of, in England,
489; transmissible from tomato to, in
England, 491; in Indiana, 40.

— tuberosum, see Potato.

— wendlandii, Alternaria solani on, in
Dutch E. Indies, 422.

Solbar, tests of, as a fungicide, in Ger-
many, 131, 223, 529.

Solidago, Coleosporium solidaginis on, in
U.S.A., 349.

Solupar, tests of,
Malaya, 140.

Sorghum (Andropogon sorghum), Colleto-
trichum graminicolum on, in Uganda,
263, 264,

— diseases in N.S. Wales, 354.

—, Helminthosporium foot rot of wheat can
infect, 60.

—, — oryzae can
231.

—, — turcicum on, in Uganda, 264.

—, mosaic of, 584; in Hawaii, 241; in
Java, 236.

—, Sclerospora on, in Uganda, 157, 264.

—, Sphacelotheca sorghi, influence of
temperature on infection by, 12;

Jrocystis

as a fungicide in

infect, in Japan,

644. GENERAL INDEX

occurrence in Egypt, 113; in India, ,
12; in Uganda, 156, 264.
[Sorghum], Tolyposporium filiferum on, in
Egypt, 113. a
—, Ustilago reiliana on, in Egypt, 113; in |
Uganda, 156, 264.

Sorghum sudanense, see Sudan grass.

— vulgare, see Sorghum.

Sorosporium reilianum, see Ustilago reiliana.

Soy-bean (Glycine), Alternaria atrans on,
in Arizona, 250.

—. aphid injury to, in Arizona, 250.

—~, Bacterium solanacearum on, in Dutch
E. Indies, 10.

—, — glycinewm and Bact. sojae on, dis- |
tinguished by action on various sugars, |
158.

— mosaic, effect of temperature on, 77.

—, Phomopsis sojae on, in N. Carolina, °
151.

—. sunburn injury to, in Arizona, 249.

Sphacelia on Pennisetum purpureum in |

Uganda, 264.

— on Pennisetum spicatum in Tanganyika, :

264.
—on Pennisetum typhoideum in Uganda,
264,

— stage of Claviceps purpurea, cultures of, |

114,

— allii, Sclerotium cepivorum in relation to,
ik

Sphaceloma ampelinum, see Gloeosporium
anpelophagum.

Sphacelotheca sorghi on sorghum in Egypt,
113 ; in India, 12; in Uganda, 156,
264; influence of temperature on in-
fection by, 12.

Sphaerella gibelliana on citrus in Spain,
405.

Sphaerium wolffensteiniani on citrus in
Spain, 405.

Sphaeronema on Hevea rubber in Dutch E.
Indies, 8.

— fimbriatum on Hevea rubber in Belgian
Congo, 577; in Malaya, 396, 426.

— — on sweet potato, measures against
introducing into British Columbia,
532; varietal resistance to, in Missis-
sippi, 441.

— pilifera probably a Ceratostomella, 342.

Sphaeropsis on dead needles of pine in
N.S. Wales, 299.

— malorum, see Physalospora cydoniae.

— ulmicola on elm in Wisconsin, 481.

Sphaerostilbe coccophila parasitic on scale
insects in Florida, 369.

— repens on Hevea rubber in Malaya,
396.

— — on tea in India, 343.

Sphaerotheca humuli on hops, fungicidal
tests with, 168.

— mors-urae on currant in Italy, 277.

—— on gooseberry in Crimea, 69, 70;
in Denmark, 563; in Germany, 132,
169, 171, 201, 223; in Holland, 53;
in Italy, 277, 293; in Norway, 548;
in Sweden, 457; in U.S.A., 454; tests

of control measures against, in Crimea, |
69, 172; in England, 376; in Ger- |

many, 171, 223; in Holland, 53; in

Illinois, 454; in Norway, 548; in
Sweden, 457.

| Sphaerotheca] pannosa on peach in Crimea,
172.

— — on rose, control in Germany, 132,
171; in Sweden, 458.

Sphaerulina trifolii on clover in US.A.,
414.

Spicaria farinosa var. verticilloides, control
of vine moth by, in France, 313,
413.

— javanica parasitic on coffee berry
borer in Dutch E. Indies, 368

— purpurogenes, biology and morphology
of, 566; inhibiting action of, on
other organisms, 567.

— verticilloides, see S. farinosa var. verti-
cilloides.

Spinach (Spinacia oleracea), Fusarium on,
in U.S.A., 100.

—, Peronospora effusa on, in Denmark,
488 ; in Texas, 256.

—, Puccinia subnitens on, in Oregon, 100.

—, X organisms in connexion with a
disease of, in Holland, 54

Spinifex hirsutus, Cintractia spinificus on, in
Australia, teratology of, 292.

Spondias lutea, wet root rot fungus on, in
Uganda, 157.

Spondylocladium atrovirens on potato in
Canada, 26.

Spongospora subterranea on potato in
Algeria, 568; in Britain, 208; in
British Columbia, 395; in Canada,
26, 465; in N. S. Wales, 354; relation
of skinspot to, 389, 567 ; transmissible
to deadly nightshade in Denmark,
563.

— — on tomato, 245.

Spore germination, factors influencing,
516.

Sporidesmium mucosum var. pluriseptatum
on vegetable marrow in Astrakhan,
535.

Sporisorium maydis, synonym of Peni-
cillium crustaceum, 167.

Sporotrichum beurmanni,
toxins of, 410, 411.

— carougeani on man in Madagascar, 21.

— globuliferum, probable control of vine
Phylloxera by, 413.

— —, control of soil dwelling pests by,
413.

— gougeroti, enzymes of, 410.

Spraying and dusting experiments with
fruit in U.S.A., 71, 219.

—, recent advances in, 225.

—, spreading agents in, 225, 375, 376.

Spruce (Picea), Polyporus schweinitzti on, in
U.S.A., 531.

—, Poria subacida on, in U.S.A., 531.

—, sap-stain of, in U.S.A., 185.

—, Torula ligniperda on, in Europe, 34.

—, Trametes pini on, in U.S.A., 531.

Squash (Cucurbita), Colletotrichum lagena-
rium can infect, 256.

Squirrels transmitting Peridermium on
pines. 561.

Stachybotrys alternans on timber in U.S.A.,
185.

enzymes and

—=

7

GENERAL INDEX 645

Stachytarpheta, Septobasidium bogoriense on,
in Java, 145.

— indica, Bacterium solanacearum on, in
Sumatra, 35.

Stack-burn of rice in U.S.A., 334.

Stagonosporopsis hortensis on bean in Nor-
way, 203.

‘Staling’ of fungal cultures, 328.

Stellaria, Hypochnus solani on, in Denmark,
563

—, Melampsorella caryophyllacearum on,

Stemonitis on timber in U.S.A., 185.

Stephania hernandifolia, Parastigmatea ner-
visita on, in S. Africa, 142.

Stephanoderes hampei, Botrytis stephanoderis
on, in Dutch E. Indies, 369.

Stereum purpureum on apple in Britain,
209 ; in New Zealand, 68; inS., Africa,
451.

— — on apricot in New Zealand, 68;
in S. Africa, 451.

— — on peach in New Zealand, 68; in
S. Africa, 451.

— —on pear in New Zealand, 68; inS.
Africa, 452.

— —on plum in New Zealand, 68; in
S. Africa, 451.

— —on Populus alba in S. Africa, 451.

— —, susceptibility to, increased by
attacks of leaf rust, 321.

— rugosiusculum identical with S. pur-
pureum, 452.

Sterigmatocystis nigra, see Aspergillus niger.

Stock (Matthiola), Plasmodiophora brassicae
on, 222.

Strawberry (Fragaria vesca), Bacillus
amylovorus on, in U.S.A., 163.

—, Marssonia potentillae on, in Canada
and U.S.A., 15.

—, Mollisia earliana on, in Canada and
U.S.A., 16, 255.

—, Mycosphaerella fragariae on, control in
Illinois, 455.

Striga orobanchoides on tobacco in S.
Africa, 476.

Sudan grass (Sorghum sudanense), Helmin-
thosporium foot rot of wheat can infect,
60.

— —, mosaic of, in Hawaii, 241.

— —~, Pseudomonas alboprecipitans can in-
fect, 447.

— —, Sclerospora graminicola on, in S.
Africa, 10.

Sugar-beet, see Beet.

Sugar-cane (Saccharum officinarum), Acro-
stalagmus glaucus and A. sacchari on
rotted setts of, in Argentina, 339.

— —, Aeginetia indica on, in the Philip-
pines, 109.

— —, Bacillus D, F, and flavidus causing
top rot of, in Argentina, 338.

—, bacteria rotting setts of, in Argentina,
339.

—, Bacterium causing leaf scald of, in
Australia, 579.

—, — vascularum on, control by drainage
in Queensland, 140; occurrence in
Australia, 140, 354, 579; varietal re-
sistance to, 140, 579.

[Sugar-cane], Bakerophoma sacchari on, in
the Philippines, 109.

—, Botryodiplodia theobromae on, in Cuba,
525.

—, Cephalosporium sacchari on, in Bar-
bados, 261 ; in the Philippines, 109.
—, Cercospora kopkei on, in Cuba, 525; in

the Philippines, 109.

—, — sacchari on, in Australia, 580.

—, — vaginae on, in Barbados, 261; in
Cuba, 525.

—, Colletotrichum falcatum on, in Australia,
580; in Barbados, 261 ; in Cuba, 525;
in Java, 8; in the Philippines, 109.

—, Cytospora sacchari on rotted setts of, in
Argentina, 339.

—, Fiji disease of, cultures of organism
causing, 234 ; etiology of, 234 ; occur-
rence in Australia and Fiji, 578, 579 ;
in N. S. Wales, 354; in the Philip-
pines, 88, 89, 109, 234.

—, Fusarium on, in Argentina, 339; in
Barbados, 260, 467.

—, gummosis of, in Java, 8. (See also
Bacterium vascularum).

—, Helminthosporium sacchari on, in
Australia (?), 580; in Barbados, 261;
in Cuba, 525.

» Hypochnus sacchari on, in Cuba, 525.

— leaf scald (Bacterium sp.) in Australia,
579.

— leaf stripe, see Phyllosticta sacchari.

—, legislation against importation of, in
India, 239; in Malaya, 238; in
Uganda, 528.

—, Leptosphaeria sacchari on, in Argen-
tina, 340; in Australia, 580; in Bar-
bados, 261; in Cuba, 525; in the
Philippines, 109.

—, Marasmius root disease of, in Austra-
lia, 580; causation of, doubted in
Argentina, 340; in Barbados, 260,
467,

—, — sacchari on, in Barbados (not para-
sitic), 260, 467 ; occurrence in Cuba,
525 ; in Guadeloupe, 33; (?) in Java,
469 ; in the Philippines, 109.

—, — stenophyllus on, in Cuba, 525.

—, Melanconium sacchari on, in Argentina,
339, 340; in Australia, 580; in Cuba,
525; in the Philippines, 109.

—, Meliola arundinis on, in the Philip-
pines, 109.

— mosaic, amoeboid bodies in, 241;
control in Argentina, 339 ; in Austra-
lia, 579, 581; im Cuba, 524, 525; in
Hawaii, 241; in Java, 34, 237; in the
Philippines, 141; in Porto Rico, 106 ;
in Trinidad, 394; in U.S.A., 106;
effect of sunlight on, 242 ; host plants
of, 33, 34, 236, 241, 390,584; occurrence
in Argentina, 339; in Australia, 579 ;
in Barbados, 260; in Cuba, 524, 525;
not in Guadeloupe, 33 ; in Hawaii, 33,
241; in Java, 8, 33, 34, 237; not in
Mauritius, 203; in the Philippines,
88, 109, 141, 468; in Porto Rico, 106.
890 ; in Trinidad, 394; in U.S.A., 106,
205 ; transmitted by Aphis maidis, 381,
585; in Cuba, 524 ; in Hawaii, 33, 241;

646 GENERAL INDEX

in Java, 237; in Porto Rico, 390; by
Peregrinus maidis, 381; possibly by
Aphis sacchari in Argentina, 339; in
Java, 237; possibly by Carolinaia, 381 ;
varietal resistance to, in Argentina,
339; in Cuba, 524, 525; in Java, 33,
237 ; in the Philippines, 89, 141, 468;
in U.S.A., 106. (See also Maize
mosaic).

[Sugar-cane], Naucoria suborbiculata on, in
Argentina, 340.

—, Northiella sacchari on, see Fiji disease.

—, Omphalia saccharicola on, in Argentina,
340.

—, Pestalozzia fuscescens var. sacchari on,
in the Philippines, 109.

—, Phyllachora sacchari on, in the Philip-
pines, 109.

—. Phyllosticta sacchari on, in Argentina,
340,

—, Phytamoeba sacchari, name given to
Northiella sacchari, the cause of. Fiji
disease, 235.

—, Plasmodiophora vascularum on, organism
resembling, in Barbados, 468.

—. Puccinia kuehnii on, in Australia,
580; in the Philippines, 109.

—, Rhizoctonia grisea on, in Barbados,
261.

—, — pallida on, in Barbados, 260, 467.

—, — solani on, in Barbados, 260, 467.

— root disease in Argentina, 340; in
Barbados, 260, 467; in Mauritius, 203.

— root rot in Java, control by hot water,
469; etiology of, 526; occurrence in,
8, 526, 584; similarity to grey speck
disease of oats, 526.

—, Sclerospora sacchari on, in Australia,
578, 579; in the Philippines, 109.

—, — spontanea on, in the Philippines,
360.

—, sclerotial disease of the leaf sheath
of, in Australia, 580.

—, Sclerotivm on, in the Philippines,
109.

—, — rolifsii on, in Cuba, 525; in the
Philippines, 109.

—, sereh disease of, control by hot
water in Java, 468; occurrence in
Java, 8; in Singapore, 469.

—, sereh-like disease of, in the Philip-
pines, 109.

—, Thielaviopsis ethaceticus on, see T. para-
doxa.

—. — paradoxa on, in Australia, 580; in
Barbados, 261; in Cuba, 525; in
Java, 8; in the Philippines, 109.

—, top rot of, in Argentina, 338; in
Queensland, 581.

—, Trichoderma lignorum on, in Barbados,
467.

—, Ustilago sacchari on, in the Philip-
pines, 89, 109.

— yellows in Argentina, 339.

— yellow stripe disease, see Mosaic

Sulphur, control of Actinomyces scabies on
potato by, 109, 519, 572; of sweet
potato diseases by, 31; fungicidal
action of, 281, 460.

— dusts for controlling fruit diseases in

New Jersey, 506; for smuts in Canada,
549.

{Sulphur] glue mixture as a fungicide for
fruit trees in New Jersey, 506.

—, ‘Pra’, as a fungicide against mildew
in Germany, 171.

Sunburn injury to cowpeas and soy-
beans in Arizona, 249.

Sunflower (Helianthus annuus), Plasmo-
para halstedii on, in Japan, 315.

—, Puccinia helianthi on, in Canada, 304.

—, Sclerotinia (?) libertiana on, in Canada,
304; in Holland, 544; in Montana,
439, 544.

—, stimulatory effect of Bordeaux mix-
ture on, 508.

‘Superol’ as a disinfectant for rubber,
140.

Supersulphur for controlling wheat bunt
in Sweden, 171.

Swede turnip (Brassica campestris), Bacil-
lus lacerans and B. bussei on, in Ger-
many, 200.

—, Phoma napobrassicae on, in New Zea-
land, 98.

—, Plasmodiophora brassicae on, varietal
resistance to, 151.

Sweet pea (Lathyrus odoratus), Bacillus
lathyri on, 99.

— —, slime bodies in relation to mosaic
of, 515.

— —, Verticillium albo-atrum on, in Bri-
tain, 150.

Sweet potato (Ipomoea batatas), Cystospora
batata on, in New Jersey, 31.

— —, Diplodia tubericola on, in Texas,
256.

— —, Fusarium batatatis and F. hyper-
oxysporum on, in New Jersey, 30.

— —, — oxysporum on, in Mississippi,
44],

— —, Monilochaetes infuscans on, in New
Jersey, 31.

— — mosaic in Arkansas, 441.

— —, mottle necrosis of, in U.S.A.,
486.

— —, Rhizopus. delemar, R. maidis, R.
nigricans, RF. nodosus, R. oryzae, R. re-
Jlecus, and R. tritici causing rot of, 464,
565; pectinase production by, 464,
566 ; temperature relations of, 465.

— —, Sphaeronema fimbriatum on, measures
against introduction into British Co-
lumbia, 532; varietal resistance to, in
Mississippi, 441.

Sycamore (Acer pseudoplatanus), Verticil-
lium albo-atrum can infect, in Britain,
150.

Syncephalastrum on timber in U.S.A.,
185.

Synchytrium endobioticum on potato, con-
tamination of soil by, 575; gall for-
mation by, 494; legislation against,
in Czecho-Slovakia, 422; in Denmark,
421; in England and Wales, 591; in
Germany, 535, 421, 518: in Holland,
421; in Italy, 387; in Norway, 202,
421; in S. Africa, 10; life-history of,
574; nature of immunity from, 574;
occurrence in Canada, 26; in Czecho-

. 5 =
a a a

GENERAL INDEX

Slovakia, 422; in England and Wales,
268, 591; in Germany, 30, 200, 421,
517, 575; in Holland, 54, 421; not in
Italy, 387; in Norway, 202, 421; in
S. Africa, 10, 352; in Sweden, 422;
in U.S.A., 143, 443; soil sterilization
against, 443 ; suggested use of X-rays
against, 325; transmissible to deadly
nightshade, 563; varietal immunity
from, tests in France, 174; in Ger-
many, 84, 175, 518, 575 ; in Scotland,
84; in U.S.A., 84, 443.

[Synchytrium endobioticum] on tomato, 245 ;
in U.S.A., 443.

Syntherisma sanguinalis, sugar-cane mosaic
on, 584.

Synthetic culture media for fungi, 82;
for soil fungi, 233.

Taphridium, Volkartia may be identical
with, 243.

Taphrina deformans,
mans.

-— minor, see Exoascus minor.

— pruni, see Exoascus pruni.

Taraxacum officinale, Protomyces pachyder-
mus on, 248.

Tea (Thea) Aglaospora aculeata on, in Cey-
lon, 294.

—, Armillaria on, in Dutch E. Indies, 9.

—. — fuscipes on, in Ceylon, 295.

—, Auricularia auricwa-judae on, in
India, 343.

—. Botryodiplodia theobromae on, in India,
fungicides against, 343,344. (See also
Thyridaria tarda).

—. Capnodium on, in Dutch E. Indies, 9.

—, Cephaleuros virescens on, in Java, 9.

—. Cercosporella theae on, in Ceylon, 294,
473.

—, Corticiwm on, in Ceylon, 473.

—,—javanicum on, see C. salmonicolor.

—, — salmonicolor on, in Dutch E.,
Indies, 9.

—, Fomes lamavcensis on, in Ceylon, 291 ;
in India, 343.

—, Glomerella cingulata on, in Assam, 344.

—, Hypochnus theae on, in Assam, 344 ;
in Dutch E. Indies, 9.

—. Kreteschmaria micropus on, in India,
343.

—, Laestadia on, in Dutch E. Indies, 9.

—, Macrophoma theicola on, in Ceylon, 7.

—, Pestalozzia on, in Ceylon, 7 ; in Dutch
E. Indies, 9.

—. — theae on, in Assam, 344; in
Ceylon, 527; differs from P. palmarum
on coco-nut in Ceylon, 527.

—, Rosellinia on, in Dutch E. Indies, 9.

—, — arcuata on, in India, 343.

—. Septobasidium bogoriense on, in Java,
145.

—, Sphaerostilbe repens on, in India, 343.

—, Thyridaria tarda on, in Dutch E.
Indies, 9. (See also Botryodiplodia theo-
bromae).

—. Ustulina zonata on, in Dutch E.
Indies, 9; in India, 343 ; in Kenya, 260,

Thapsia, Protomyces macrosporus on, 242.

Thea, see Tea.

see Exoascus defor-

647

Thelephora terrestris (T. laciniata) on pines
in S. Australia, 298.

Theobroma cacao, see Cacao,

Thielavia basicola on Chenopodium album in
Ireland, 117.

— — on flax in Ireland, 117.

— — on peas in Switzerland, 303.

-—— — on Senecio vulgaris in Ireland, 117.

— — on tobacco in Florida, 475; in
Kentucky, 37; in the Philippines,
109 ; relation of soil temperature to,
136 ; varietal resistance to, 37.

— — on watermelon in Oregon, 68.

Thielaviopsis ethaceticus, see T. paradoxa.

— paradoxa on coco-nut in Florida, 23 ;
in Guadeloupe, 33; in Madras, 79 ; in
the Philippines, 109.

— — on pineapple in Florida, 23; in
the Philippines, 109.

— — on sugar-cane in Australia, 580;
in Barbados, 261; in Cuba, 525; in
Java, 8; in the Philippines, 109.

Thuja plicata, Keithia thujina on, in Ire-
land, 348.

— —, Portia weirii on, in U.S.A., 531.

Thyella, Coleosporium ipomoeae on,in U.S.A.,
348.

Thyridaria tarda on tea in Dutch E.
Indies, 9. (See also Botryodiplodia theo-
bromae).

Tilia americana, see Basswood.

Tillantin B, tests of, for seed disinfec-
tion, 170.

Tilletia on wheat, control in Canada, 254;
in England, 308 ; in Oregon, 206; in
Washington, 264; relation of spore
load to infection by, 262.

— ‘caries’ on wheat, control in Ger-
many, 511; in Sweden, 171; occur-
rence in Denmark, 487.

— levis on wheat, control in Canada,
258, 459; in Germany, 399, 503; in
U.S.A., 458; influence of fertilizers
on, 503; occurrence in Canada, 253,
303, 459; tests of fungicides against,
in Germany, 554, 557.

— tritici on wheat, apparatus for seed
treatment against, in Germany, 224 ;
control in Austria, 538; in Canada,
253, 459 ; in France, 74 ; in Germany,
161, 169, 170, 399, 416; in Italy, 322 ;
in Sweden, 19; in U.S.A., 73, 458; in
Wales, 400; influence of fertilizers on,
503; of ultra-violet rays, X-rays, and
radium on, 324; occurrence in Canada,
253, 303, 459 ; in Germany, 161, 169,
200, 224, 399, 416; in U.S,A., 13, 73;
relation of soil moisture and tem-
perature to, in U.S.A, 13; tests of
fungicides against in Germany, 553,
554, 557; varietal resistance to, in
California, 392.

Timber, blueing of coniferous, in Britain,
49, 50; in U.S.A., 107, 185.

—, Ceratostomella on, in U.S.A, 107, 185.

—, — picea and C. pini on, in Britain,
49,

—, Lentinus lepideus on, in U.S.A., dis-
semination and temperature relations
of, 146.

648

[Timber], Lenzites saepiaria on, in U.S.A.,
51, 147.

—, — trabea on, in U.S.A., dissemination
and temperature relations of, 148.

—, list of fungi causing mould of, in
U.S.A., 185.

—, Phellinus (Fomes) cryptarum on, at
Versailles Palace, 97.

—, sap-stain and moulds of, control in
U.S.A., 186

—, Torwla ligniperda on, 34.

Timothy grass, see Phlewm pratense.

Tip burn of lettuce in Colorado, 528.

—— of potato, etiology and develop-
ment of, in Vermont, 28.

Tipuana tipa, Ganoderma sessile on, in
Argentina, 17.

Tobacco (Nicotiana), Bacillus
on, in Switzerland, 303.

—, — pseudozoogloeae on, in Sumatra, 9.

—, Bacterium angulatum on, control in
Virginia, 245; dissemination, 245;
476; occurrence in S. Africa, 477; in
Virginia, 245; physiology of, 157;
soil infection with, 476.

—, — solanacearum on, in Dutch E. Indies,
8, 35, 295, 314; in Florida, 474; in
the Philippines, 109, 261, 445.

—, — tabacum on, control, 38, 39, 345,
474, 476; occurrence in S. Africa,
37, 477; in U.S.A., 37, 245, 345, 440,
473, 474, 476; physiology of, 157;
viability of, 38, 40.

—, — tumefaciens causing appositional
growth in galls on, 55; producing
fasciation in, 10; producing two types
of crown gall on, 397.

—, brown spot of, in S. Africa, 477.

—, Cercospora nicotianae on, in Florida,
475; in the Philippines, 109.

—, ‘frenching’ of, in S. Africa, 477.

—,‘kroepoek’ of, in Dutch E. Indies,
9

maculicola

— leaf curl in Dutch E. Indies, 9.

—, Macrophoma nicotianae on, in St.
Thomas Island, 589.

—, Macrosporiwm longipes on, in S. Africa,
476,

— mosaic, effect of temperature on, 77 ;
intracellular bodies in, 513; occur-
rence in Dutch E. Indies, 9, 35; in
England, 489, 491; in Florida, 474;
in the Philippines, 109; in the Trans-
vaal, 477; size of virus particles of,
133; transmitted from cucumber
through Capsicum in U.S.A., 513; from
tomato in England, 491; from other
Solanaceae in Florida, 474; in Suma-
tra, 35.

—, Oidium on, in Dutch E. Indies, 9; in
S. Africa, 477.

—, Peronospora hyoscyami on, in N. S.
Wales, 354.

—, Phyjllosticta nicotianae on, in Florida,
474,

—, Phytophthora nicotianae on, in Dutch E.
Indies, 8, 36, 296; in Florida, 476 ;
stable manure disseminates in Java,
36.

—. Pythium on, in Sumatra, 296.

GENERAL INDEX

[Tobacco] ‘sand drown’ associated with
ae deficiency in U.S.A., 80,
421,

—, Sclerotium rolfsii on, in the Philip-
pines, 109 ; in Sumatra, 314.

—, Striga orobanchoides on, in S. Africa,
476.

—, Thielavia basicola on, in Florida, 475 ;
in Kentucky, 37; in the Philippines,
109; soil temperature relations of,
136; varietal resistance to, 37.

Tolyposporium filiferum on sorghum in
Egypt, 113.

— penicillariae on Pennisetum typhoideum in
India, 259.

Tomato (Lycopersicum esculentum), Alter-
naria solani on, in Dutch E. Indies,
422; in Germany, 201.

—, Aplanobacter dissimulans on, 347.

—, — michiganense on, 246, 347; organ-
ism resembling, on, in Pennsylvania,
444,

—, Ascochyta lycopersici on, in Denmark,
448; in Germany, 201.

—, Bacillus aroideae on, in Virginia,
sprays against, 346.

—, — carotovorus on, in England, 347.

—, — lathyri on, in Denmark, 246; in
England, 99, 347; in New Zealand,
430; in Pennsylvania, 443.

—, — mesentericus associated with Phoma
Jferrarisit on, 91.

—, bacterial disease of, in Switzerland,
303 ; in Pennsylvania, 443.

—, Bacteriuh exitiosum on, 246 ; in Penn-
sylvania, 444.

—, — solanacearum on, in Norway, 203 ;
in Pennsylvania, 444; in the Philip-
pines, 261, 445; in Sumatra, 35.

—, Basisporium gallarum on, in California,
296.

—, Botrytis on, in Denmark, 246; in
England, 490.

—, — cinerea on, in England, 347.

—, bright speck of, disease resembling,
in Denmark, 488.

—, Cladosporium fulvum on, in Denmark,
246, 488; in England, 347; in Ger-
many, 132, 529; in Norway, 203; in
Trinidad, 335; use of solbar against,
132, 529.

—, Didymella lycopersici on, in Denmark,
488.

—, Fusarium on, in England, 347; in
Morocco, 54 ; temperature relations of,
in U.S.A., 67, 136.

—, — ferruginosum on, in Britain, 149.

—, — lycopersici on, 245; in Arkansas,
440 ; in England, 148, 347 ; in Indiana,
10, 40; in Mississippi, 441; in Mis-
souri, 347; in Texas, 256; in U.S.A.,
40, 428; relation of hydrogen-ion con-
centration and soil moisture to, 477 ;
temperature relations of, 428; trans-
mitted by seed, 92 ; varietal resistance
to, 40, 441.

—, — oxysporum on, 245; in Britain, 149.

—, — sclerotioides on, in Britain, 149.

— leaf roll in Denmark, 246; in Moroe-
co, 54.

GENERAL INDEX

[Tomato], Macrosporium on, in Indiana.
41; in Morocco, 54.

—, — solani on, 245; in Denmark, 246.

—, — tomato on, 245

—, Melanconium on, 245.

— mosaic, aphids and probably flea- ,
beetles transmit, 40; carriers of, in |

England, 491; effect of temperature
on, 77; hosts of, in England, 491; in
Indiana, 40 ; occurrence in Astrakhan,
535; in Denmark, 246; in England,
347, 489 ; in Indiana, 40; protozoa in,
227 ; intracellular bodies in, not pro-
tozoa, 514, 516; transmitted to Petunia,
Solanum, and tobacco in England, 491;
to Lycopersicum, Physalis, and Solanum
in Indiana, 40.

rT OA ik lycopersici on, in Germany,

—, Oospora lactis on, in New Jersey, 91.

—, Orobanche aegyptiaca on, in Astrakhan,
207.

—, Penicillium on, in England, 347.

—, Phoma destructiva on, 245; in Norway,
208.

—, —ferrarisii on, in Italy, 91.

—, Phytobacter lycopersicum on, in Astra-
khan, 207

—, Phytophthora cryptogea on, 245; in
Denmark, 246; in England, 346.

—, — infestans on, 245; in Denmark,
246 ; in Virginia, 346.
—, — parasitica on, 245; in British
Columbia, 395 ; in England, 346.

—, — lerrestris on, see P. parasitica.

—, Puccinia pittieriana on, 245,

—, Pythium on, 245.

—, Rhizoctonia on, in Trinidad, 335.

—, — solani on, in Denmark, 246; in
Norway, 208.

—, Rhizopus nigricans on, 245.

—, Sclerotinia libertiana on, in Canada (?),
28; in Germany, 201.

—, — sclerotiorum on, in Denmark, 246,

—, Sclerotium rolfsii on, in Denmark,

—, — setosum on, in England, 347, 489.

—~, Septoria lycopersici on, control in Ber-
muda, 307; in U.S.A., 346, 443; oc-
currence in Denmark, 246; in Ger-
many, 201; in S. Australia, 292.

—, Spongospora subterranea on, 245.

—, spotted wilt of, in N. S. Wales, 354.

—, stimulatory effect of Bordeaux mix-
ture on, 507.

—, Synchytrium endobioticum can infect,
in U.S.A., 443,

—, Vermicularia varians on, in France,
—, Verticillium albo-atrum on, 245; in
Britain, 148, 347 ; in Denmark, 246.

—, — lycopersici on, 245.

—, winter blight or streak of, in Canada,

Top rot of sugar-cane in Argentina, 338 ;
in Australia, 581.

Torula ligniperda on various timbers in
US.A. and Europe, 34,

Trachysphaera fructigena on cacao in Gold
Coast, 495, 497.

649

| Trachysphaera fructigena] on coffee in Gold
Coast, 495.

Trametes gibbosa on cacao in St. Thomas
Island, 589.

— hispida, see T. trogii,

— incondifa on Ptaeroxylon utile
Africa, 142.

— obstinatus on Acacia and Citrus in S.
Africa, 142.

— odorata on slash wood in U.S.A., 531.

— ohiensis on coco-nut in St. Thomas
Island, 589.

— pini on conifer stumps in U.S.A,
531.

— — on Douglas fir in U.S.A.,
205.

— — on Pinus maritima in the Pyrenees,
431; in U.S.A., 5381.

— radiciperda, see Fomes annosus.

— robiniophila on Robinia pseud-acacia in
Michigan, 189.

— sanguineim on eacao in St. Thomas
Island, 589.

— sepium on cacao in St. Thomas Island,

— serialis on timber in U.S.A., 146.

— sprucei on cacao in St. Thomas Island,
589.

— suaveolens, ash analysis of, 284,

— subflava on Celtis kraussiana in 8. Africa,
142,

— trogii on Schinus dependens in France,
300.

Tranzschelia punctata, see Puccinia pruni-
spinosae.

Trees, Polystictus on living, in U.S.A.,
484.

Trema bracteola, Fomes yucatensis on, in 8,
Africa, 142.

Trichocladus ellipticus, Isipinga contorta on,
in S. Africa, 141.

Trichoderma on timber in U.S.A., 186.

— lignorum on sugar-cane in Barbados,
467.

Tricholoma-like fungus on cacao in Togo-
land, 210,

T ichophyton acuminatum, T. gypseum aster-
oides, and T. rosaceum, physiology and
toxie action of, 411.

Trichothecium roseum on Gnomonia erythro-
stoma in Switzerland, 277.

Trifolium, see Clover.

— alexandrinum, see Berseem.

Triticum, see Wheat.

Tropaeolum, see Nasturtium.

Trypaflavin, effect of, on potato tubers
in Germany, 169.

Trypanosomes in latex-bearing plants,
176, 229, 424, 523.

— in leaf roll and mosaic plants, 227,
518, 515, 516.

Tsuga canadensis, Torula ligniperda on, in
U.S.A., 34.

— heterophylla, Echinodontium tinctorium on,
in U.S.A., 581.

— mertensiana, Echinodontium tinctorium on,
in U.S.A., 581,

Turnip (Brassica campestris), Bacillus caro-
fovorus on, in Bermuda, 806; in Nor-
way, 203,

in S.

107,

650

{Turnip}, Bacterium campestre on, see
Pseudomonas campestris.

—, Plasmodiophora brassicae on, in Den- |

mark, 487.

—, Pseudomonas campestris on, in Ber- |

muda, 306.

—, — destructans on, in Wales, 196.

—, Swedish, see Swede turnip.

Typhula graminis on barley in Germany,
58.

— trifolii on red clover in Norway, 202.

Tyroglyphus longior infesting fungus cul-
tures, 525.

Ulmus, see Elm.

Ultra-violet rays, fungicidal action of,
324,

Umbbelliferae, specialization of Proto-
mycetaceae on, 242.

Uncinula necator on vine, control in
Austria, 532 ; in France, 463, 530; in
Germany, 132, 255; in Italy, 326; in
Malta, 536; in New Zealand, 533;
in §S. Australia, 353; occurrence in
Astrakhan, 207, 535; in Austria, 532 ;
in Cyprus, 394; in France, 463, 532 ;
in Germany, 201, 255; in Italy, 326;
in Malta, 536; in Morocco, 54; in
New Zealand, 533; in S. Australia,
353.

Ungulina annosa, see Fomes annosus.

— inzengae, see Fomes fomentarius.

Uredo fici, see Kuehneola fict.

— kuehnii, see Puccinia kuehnii.

Urocystis bolivari on Lolium perenne in
Spain, 142,

— cepulae on onion, control in U.S.A.,
206 ; life-history of, 251; new appara-
tus for treating, 460; occurrence in
Britain, 208 ; in U.S.A., 206, 251.

— colchict (suspected) on Bulbocodium
vernum in Holland, 54.

— coralloides on Indian mustard (Brassica),
in India, 259.

— galanthi on snowdrop in Germany,
449,

— occulta on rye, control in Germany,
170, 417; in Sweden, 19; occurrence
in Denmark, 487.

— tritici on wheat, factors influencing
germination of, 398.

Uromyces of Japan, 586.

— betae on beet in Morocco, 54.

— — on wild beet in Denmark, 563.

— dictosperma on Euphorbia arkansana in

Indiana, seed transmission of, 472,

473.

— fabae on beans in Morocco, 54.

— pisi on Lathyrus and peas, specializa-
tion of, in Moscow, 341.

— proeminens on Euphorbia dentata and E.
preslii in Indiana, seed transmission
of, 472, 473.

— viciae-unijugae in Japan, 586.

Urophlyctis alfalfae on lucerne in France,
493.

Urtica latex, inoculations of mice with,
424,

GENERAL INDEX

Urticaceae, amoebae in latex of, 177.

—, human trypanosomes can live in
latex of, 523.

Uspulun, chemotherapeutical index of,
552, 556.

—, fungicidal action of, on bunt spores,
162, 512, 555.

— not injurious to animals, 512.

—, stimulatory action of, 20, 162, 422,
509, 510.

—, use of, against barley smuts in Ger-
many, 161; beet root rot ifGermany,
224, 510; celery rust in Germany, 20 ;
Colletotrichum lindemuthianum on beans
in Germany, 20; Fusarium nivale on
rye in Germany, 161, 511 ; Gibbereila
saubinetti in Holland, 53; Helmintho-
sporium gramineum on barley in Austria,
538; in Germany, 161, 399, 416, 511 ;
oat smut in Czecho-Slovakia, 550 ;
Plasmodiophora brassicae in Germany,
222; Pythium on tobacco in Sumatra,
294; Urocystis occulta on rye in Ger-
many, 170; wheat bunt in Germany,
161, 599, 416, 511; in Sweden, 171.

Ustilago avenue, cytology and culture of,
in Russia, 587.

— — on oats, control in Austria, 538 ;
in Canada, 253, 256, 549 ; in Czecho-
Slovakia, 550; in Germany, 161, 169,
170, 399, 417, 504; in Wales, 400;
effect of ultra-violet and X-rays on,
324; influence of fertilizers on, in
Germany, 504; method of infection
by, 214; occurrence in Austria, 538 ;
in Canada, 253, 255, 303, 549; in
Denmark, 487 ; in Germany, 161, 169,
170, 200, 214, 399, 417, 504; in
Russia, 587; in Wales, 401.

— bromivora on Bromus ciliatus in Canada,
254.

— —, smut resembling, on Agropyron
tenerum in Canada, 254.

— eleusinis on Eleusine coracana in India,
308, 309.

— hordei on barley, chemotherapeutical
studies of, 551, 553; control in Ger-
many, 161, 170; in Sweden, 19; in
U.S.A., 458 ; in Wales, 400 ; effect of
ultra-violet and X-rays on, 324;
occurrence in Denmark, 487 ; in Ger-
many, 161 ; in Sweden, 19.

— levis on oats in Canada, 304, 459; in
U.S.A., 458; in Wales, 401.

— maydis, see U. zeae.

— nuda on barley, control in Austria,
538; in Germany, 400; in U.S.A.,
458 ; effect of ultra-violet and X-rays
on, 324; influence of fertilizers on, in
Germany, 504.

— reilianw on sorghum in Egypt, 113; in
Uganda, 156, 264.

— sacchari on sugar-cane in the Philip-
pines, 89, 109.

— tritici on wheat, control in Austria,
538 ; in Germany, 400, 550 ; influence
of fertilizers on, in Germany, 504;
occurrence in Austria, 538 ; in Canada,
303; in Germany, 400, 550; in
Uganda, 264.

a

EEE ee. ee

id

GENERAL INDEX

[ Ustilago zeae] on maize, influence of ultra- :

violet and X-rays on, 324; occurrence
in Astrakhan, 207; in Canada, 255.

Ustulina zonata in Uganda, 156.

— — on coffee in Kenya, 260.

— — on peach and pear in Kenya,
260.

— —on Hevea rubber in Ceylon, 7; in
Kenya, 260; in Malaya, 32, 396.

— — on tea in Dutch E. Indies, 9; in
India, 343; in Kenya, 260.

Vasclomyces xanthosomae on cocoe in
Jamaica, 103.

Vegetable marrow (Cucurbita
Oidium on, in Astrakhan, 207.

— —~, Sporidesmium mucosum var. pluri-
septatum on, in Astrakhan, 535.

Venturia inaequalis, factors influencing
spore germination in, 516.

— — on apple, ascospore ejection in,
122; associated with Nectria galligena
in Britain, 318; control in Arkansas,
440; in Britain, 376; in Canada, 255,
304; in Connecticut, 220; in Ger-
many, 169; in Illinois, 453 ; in Michi-
gan, 71, 371; in Montana, 439; in
New Hampshire, 281; in N. S. Wales,
553 ; in New York, 506 ; in New Zea-
land, 121; in Ohio, 442, 505 ; in Wis-
consin, 257, 492; occurrence in Ar-
Kansas, 440; in Astrakhan, 207, 535;
in Canada, 255, 304; in Connecticut,
220; in Crimea, 172; in Germany,
169 ; in Massachusetts, 440 ; in Michi-
gan, 371; in Montana, 439; in New
Hampshire, 281; in N. S. Wales,
353; in New Zealand, 121, 122, 123;
in Ohio, 442, 505; in Wisconsin, 257,
492; spreads in cool storage, 123;
toxic action of sulphur on, 281;
varietal susceptibility to, in Massa-
chusetts, 440.

— pirina on pear, ascospore ejection in,
122; control in Germany, 169; in
Illinois, 454; in Michigan, 72; in
New Zealand, 121; in S. Africa, 126;
occurrence in Astrakhan, 207, 535 ;
in Crimea, 172; in Denmark, 218;
in Germany, 169; in Illinois, 454; in
N. S. Wales, 353; in New Zealand,
121, 122.

Vermicularia circinans, see Colletotrichum
circinans.

ir herbarum on carnations in France,

70,

‘veoh on Physalis peruviana in France,

— — on potato, leaf roll caused by, 27 ;
occurrence in Canada, 26; in France,
27, 173, 334; in S. Australia, 292.

— — on tomato in France, 26.

— zingibereae on ginger in India, 249.

Veronica agrestis, Rhizoctonia violacea on,
in England, 451.

Versailles Palace, destruction of timber
in, by Fomes cryptarum, 97.

Verticillium on potato in Dutch E. Indies,
423; in Pennsylvania, 443.

pepo),

651

[Verticillium] albo-atrum on eggplant in
New Jersey, 110.

— — on potato in Canada, 332, 465; in
Morocco, 54; in Oregon, 206.

— — on sweet pea in Britain, 150.

— — on tomato, 245; can infect Antir-
rhinum, Capsicum, cotton, cucumber,
eggplant, potato, sycamore, and Ulmus
in Britain, 150; occurrence in Britain,
148, 347 ; in Denmark, 246.

— lycopersici on tomato, 245.

Vetch (Vicia), Ascochyta pisi on, in New
Zealand, 505.

Vicia spp., see Vetch.

— faba, see Bean (broad).

Vigna catjang and V. sinensis, see Cowpea.

Vine (Vitis), apoplexy of, see Fomes
igniarius.

—, Aureobasidium (?) on, in N. S. Wales,

54.

—, — vitis on, in France, 153; in S.
Australia, 152.

—, Bacterium tumefaciens on, in France,
532.

—, black measles of, in California, 438.

—, Botrytis cinerea on, in France, 532 ; in
Switzerland, 45, 302.

—, California disease of, in California,
438,

— chlorosis, treatment with iron sul-
phate, 552.

—, Coniothyrium diplodiella on, in Ontario,
436 ; in Switzerland, 45, 302.

—, Cryptosporella viticola on, in France,
532.

—, die-back of, in France, 188.

— diseases in Illinois, control of, 454.

—, Fomes igniarius on, in France, 326,
437, 528.

—, Gloeosporium on, in Arizona, 155.

—, — ampelophagum on, in France, 532 ;
in N. S. Wales, 437; in S. Africa,
353; in S. Australia, 353.

—, — fructigenum on, in New Zealand,
534,

—, Glomerella cingulata on, in France,
532.

—, Guignardia bidwellii on, in France,
532.

—, obscure disease of, in Australia,
153.

—, — fruit rot of, in Arizona, 155.

—, Oidium of, see Uncinula necator.

—, physiological diseases of, in Cali-
fornia, 438.

—, Plusmopara viticola on, control in
Algeria, 104; in Austria, 532, 533; in
Cyprus, 394; in France, 531; in Ger-
many, 254; in Italy, 326, 562; in
Malta, 536; in N. S. Wales, 354; in
Switzerland, 44; critical periods for
attack in Algeria, 104; forecasting in
Italy, 6; occurrence in Algeria, 104;
in Australia, 292; in Austria, 532,
533; in Cyprus, 394; in Germany,
201, 254; in Italy, 6, 326, 562; in
Malta, 536; in Morocco, 54; in N. S.
Wales, 354; in S, Australia, 292, 353 ;
in Switzerland, 302.

— Pseudopeziza tracheiphila on, in Austria,

652

532, 533; in Germany, 201; in Swit-
zerland, 302.

[ Vine], ‘ roncet’ disease of, in Malta, 536,

—, scald of, in New Zealand, 534.

—, Sclerotinia fuckeliana on, in New
Zealand, 534.

—, shanking of, in New Zealand, 534.

—, Sphaceloma ampelinum on, see Gloeo-
sportum ampelophagum,

—, Uncinula necator on, control in Austria,
532; in France, 468, 531; in Ger-
many, 132, 255; in Italy, 326; in
Malta, 5386; in New Zealand, 583; in
S. Australia, 353 ; occurrence in As-
trakhan, 207, 535; in Austria, 532;
in Cyprus, 394; in France, 463, 532 ;
in Germany, 201, 255; in Italy, 326;
in Malta, 5386; in Moroeco, 54; in
New Zealand, 533; in S. Australia,
353.

—, warted leaves of, in New Zealand,
534.

—, water berries of, in California, 438.

Violet (Viola), Bacillus carotovorvs on, in
England, 119.

—, Cercospora violae on, in Morocco, 54.

Virgilia capensis, Fomes geotropus on, in
S. Africa, 142.

Virus diseases of plants, 379, 513, 514,
515. (See also Mosaic, Leaf roll).

Viticultural station, Lausanne, work of,

Vitis, see Vine.

Volkartia, perennial in the underground
parts of its hosts, 243.

— separation from Taphridium doubtful
243.

— rhaetica, systematic position of, 248.

— umbelliferarum on Heracleum sphondy-
lium, systematic position of, 243.

‘Vrotpootje’ disease of wheat in S,
Africa, relation to Fusarium and
Ophiobolus cariceti, 536.

?

Wallflower (Cheiranthus cheiri), Plasmo-
diophora brassicae on, 223.

Walnut (Juglans regia), die-back of, in
France, 187, 347.

—, Pseudomonas juglandis on, in S. Aus-
tralia, 292.

—, wound dressing for, 550.

—, black (Juglans californica), obscure
disease of, in California, 393.

Watermelon (Citrullus vulgaris), Bacillus
tracheiphilus on, in U S.A., 280.

—, Cladosporium cucumerinum on, in
U.S.A., 280.

—, Colletotrichum lagenarium-on, in Texas,
256; in U.S.A., 280.

—, Diplodia tubericola on, in Texas, 256;
in U.S A., 280.

—, Fusarium niveum on, in U.S.A., 280.

—, Mycosphaerella citrullina on, in U.S.A.,
280.

—, Oidium on, in Astrakhan, 207.

—, Orobanche aegyptiaca on, in Astrakhan,
207.

—, Pseudoperonospora cubensis on, in
US.A., 280.

—, Sclerotium rolfsii on, in U.S.A., 280.

GENERAL INDEX

[Watermelon], Thielavia basicola on, in
U.S.A., 68, '

Weeds as carriers of crop diseases in
Denmark, 563.

Weeping willow (Dutch), see Salix alba
var. vitellina pendula,

Weizenfusariol against cereal diseases
in Germany, 161.

Wheat (Triticum), bright speck disease of,
in Denmark, 488; in Norway, 202.

— bunt, see Tilletia.

—, Cladosporium herbarum on, in Uganda,
264,

—, Claviceps purpurea on, in France, 114,
160.

—, copper dusts increase the productivity
of, in Italy, 322.

—, crinkle joint of, cause unknown, in
Canada, 304.

—, Erysiphe graminis on, in Denmark,
487; increases acidity of infected
plants, 361.

—, formaldehyde injury to, 266.

—, Fusarium on, in Denmark, 487; in
S. Africa, 536; tolerance to acidity
and alkalinity of, 12.

—, — avenaceum on, influence of CO,
and hydrogen-ion concentration on,
383.

—, — culmorum on, in Kenya, 260; in-
fluence of CO, and hydrogen-ion con-
centration on, 383.

—, — herbarum on, influence of CO, and
hydrogen-ion concentration on, 383.

—, Gibberella saubinetii on, in Canada,
304; in Holland, 53; in U.S.A., 257,
536; relation of soil moisture and
temperature to, in U.S.A., 257, 536.

—, ‘ginocchiatura’ of, in Italy, 561.

—, Helminthosporium on, in N. S. Wales,
354; in Sudan, 60; in U.S.A., 59,
106; strains of, 60.

—, — sativum on, in Canada, 304.

—, — sorokinianum on, in Uganda, 156,
264.

—, Leptosphaeria on, in Denmark, 487.
—, — herpotrichoides on, in France, in-
fluence of various chemicals on, 11.

—, — tritict on, in Uganda, 156, 264.

—, mycorrhiza of, in Italy, 172.

—, Ophiobolus on, in Denmark, 487,

—, — cariceti on, influence of various
chemicals on, 11; occurrence in
Britain, 208; in France, 11; in N. S.
Wales, 354; in S. Africa, 586; in
U.S.A., 106, 206.

—, Phoma hennebergii on, synonymous
with Septoria nodorum, 497.

—, Piricularia on, in India, 259.

—, Pseudomonas alboprecipitans can infect,
447,

—, Puccinia glumarum on, genetics of
resistance to, 57; influence of climate
on, 361; occurrence in Austria, 538;
in France, 361 ; in India, 307; not in
Uganda, 263; varietal resistance to,
in India, 307.

—,— graminis on, aecidial stage of, in
Australia, 307; barberry eradication
against, in Denmark, 199, 487, 499;

GENERAL INDEX

in U.S.A., 106, 399, 489; in Western
Europe, 499; biologic forms of, in
Canada, 253, 358; in U.S.A., 158;
cytology of resistance to, 359, 401;
hydrogen-ion concentration in relation
to resistance to, 13, 361; influence of
climate on, 361; losses caused by, in
Denmark, 199; occurrence in Astra-
khan, 207; in Australia, 307; in
Canada, 253, 303, 357; in Denmark,
199; in France, 361; in India,
307; in Uganda, 264; in U.S.A,
106, 112, 158, 439; temperature rela-
tions of, 13; varietal resistance to, in
India, 307 ; in Morocco, 54 ; in U.S.A.,
106, 112, 158, 392 ; viability of spores
of, 14.

[ Wheat, Puccinia] triticina on, influence of
climate on, 361 ; occurrence in Austria,
538 ; in Canada, 254, 303; in France,
361; in India, 307; in Uganda. 156,
264; varietal resistance to, in India,
307; in U.S.A., 113, 392.

—, ‘rosette’ disease of, in U.S.A., 106.

— scab, see Gibberella saubinetii.

—, Septoria graminum on, in Morocco, 54.

—, — nodorum on, in Arkansas, 497,
498 ; in Canada, 304; in U.S.A., 211;
supposed perithecial stage of, 212.

—, — tritici on, in U.S.A., 212; stated
to differ from S. graminum, 212, 497 ;
from S. nodurum, 497.

—, soil acidity disease of, in Germany,
499.

—, stimulating effect of seed disinfec-
tants on, in Italy, 322; in Saxony,
550.

—, Tilletia on, control in Britain, 308 ;
in Canada, 254; in France, 74; in
Oregon, 206; in Washington, 264;
factors influencing infection by, 262.

—, — ‘caries’ on, control in Sweden,
171; occurrence in Denmark, 487 ;
tests of mercury fungicides against, in
Germany, 511.

—,— levis on, control in Canada, 253,
459 ; in Germany, 399,503 ; in U.S.A.,
458; influence of fertilizers on, 503;
occurrence in Canada, 253, 303, 459;
tests of fungicidesagainst, inGermany,
555, 557.

—, — tritici on, apparatus for seed treat-
ment against, in Germany, 224 ; con-
trol in Austria, 538; in Canada, 253,
459; in France, 74; in Germany,
161, 169, 170, 399, 416; in Italy, 322;
in Sweden, 19; in U.S.A., 73, 458 ;
in Wales, 400; influence of fertilizers
on, 503; of ultra-violet rays, X-rays,

653

and radium on, 324; occurrence in
Canada, 253, 303, 459; in Germany,
161, 169, 200, 224, 399, 416; in U.S.A.,
13, 73 ; relation of soil moisture and
temperature to, in U.S.A., 13; tests
of fungicides against, in Germany,
553, 554, 557 ; varietal resistance to,
in California, 392.

[| Wheat], Urocystis tritici on, germination
of, 398.

—, Ustilago tritici on, control in Austria,
538 ; in Germany, 400, 550; influence
of fertilizers on, 504; occurrence in
Austria, 538: in Canada, 303; in
Germany, 400, 550; in Uganda, 264.

—, ‘vrotpootje’ disease of, in S. Africa,

— and rye hybrid, Olaviceps purpurea and
Puccinia graminis on, in France, 362.
White pine blister rust, see Cronartium
ribicola.

‘Wisa’ disease of birch in Finland, 384.

‘Witches’ broom’ on Broussonetia papyri-
Sera in Sicily, 404.

— — on citrus in Sicily, 404.

— — on coffee in Uganda, 409.

— — on cypress in Sicily, 404

Wound dressing for trees, 530.

X organism found ina spinach disease
in Holland, 54.

X-rays, control of bunt and smut of
cereals by, 324.

Aanthosoma sagittifolium, see Cocoe.

Aylaria thwaitesii on rubber in Ceylon,
576

— polymorpha on pear in Switzerland,
302.

Ayleborus dispar, association of Monilia
candida with, 561.

Aymalos monospora, Fomes rimosus on, in
S. Africa, 142.

Yeast, action of ‘ bios’ on, 284.

— spot of lima beans in Virginia, 194,

‘Yellow grains’ of rice in U.S.A., caused
by Protoascus colorans, 334,

Yellows of cabbage, see Fusarium conglu-
tinans.

—of raspberry, see Raspberry leaf curl
and mosaic.

Yellow stripe disease of sugar-cane, see
Sugar-cane mosaic,

Zapupe, see Agave zapupe.

Zea mays, see Maize.

Zingiber officinale, see Ginger.

Zinnia, Macrosporium caudatum on, in
Denmark, 488,

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