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Issued by |
_. THE PLANT DISEASE SURVEY, DIVISION OF MYCOLOGY AND DISEASE SURVEY
| BUREAU OF PLANT INDUSTRY, SCILS, AND AGRICULTURAL ENGINEERING
_ AGRICULTURAL RESEARCH ADMINISTRATION
UNITED STATES DEPARTMENT OF AGRICULTURE
PLANT DISEASE ‘SURVEYS
IN THE SOUTHEASTERN UNITED STATES IN 1943
June 15, 1944
Plant Disease Reporter is issued as a service to plant pathologists
ighout the United States. It contains reports,summaries,observations,
d comments submitted voluntarily by qualified observers. These reports
n are in the form of suggestions, queries,and opinions,frequently pure-
tentative, offered for consideration or discussion rather than as mat-
of established fact. In accepting and publishing this matcrial the.
ey serves merely as an informational _
or the subject matter.
sion of Liycology and Disease Surv ves i
g housc. It does not assume responsibility
Ae eg SL ee er
rect a : a Ae ea SE
. > S eee . PO Tose eet
232
PLANT _ _DISEASE SURVEYS.
\
iN THE SOUTHEASTERN UNITED STATES 5S IN 1943
Plent Disease Reporter
Supplement 148 — . ~ dune 15, 1944
J CONTENTS
Virginie, by Carlton F. Taylor .....+++-++s-s 233
West. Virginia, by Carlton F. Taylor . « « « «ss 239
Kentucky, Baie tes ee la es es ae es we ah5
Tobacco Diseases in Kentucky, 1943, by
. 0... Waites endive ie Seance - so we SG ee 247
Tennessee, oy Wa: a Bg ie als ee i ea te a 29
Diseases of Soybeans and Peanuts in the
Carolinas, by he (Bay Gee eer Bie ie es wt 25k
Georgia, by G.\ Ms, SSbGGe veo = aie meee we
Florida, by G. M s Stone _@ s e e e e @ e e a e
Alabama, by G. M, Stone and J. fg BES. tac Re? a 276
a e
NN
On
tw 0
Mississippi and Louisiana, by L. H. PEGESOn: w «a5 28C
Arkansas, by Howard We Larsh. « ..« ic ss « 6 6.0% 28h,
Miesouss,,. by-Sha, |W BRCRZ oo eae tal ee iy) iw we Le, oe 29h,
233
EMERGENCY PLANT DISEASE SURVEY IN VIRGINIA
1913
Carlton F. Taylor
Work on the Emergency Plant Disease Prevention Project was started in
Virginia in August, 1943. At that time small grains had already been
harvested, as had early season vegetables, and only midsummer and autumn
crops were available for observation. This report is confined largely
to those diseases seen by the writer. Tne two exceptions are the infor-
‘Mation drawn from an unpublished report by Dr. G. K. Parris and Mr. H. W.
Ridgway on a survey of tomato diseases on the Eastern shore of Virginia,
and a report on tobacco diseases in Virginia prepared for the writer by
Dr. W. A. Jenkins.
Crop losses reported are estimates, based on counts or the writer's
estimate in conjunction with the estimates of pathologists, County Agents,
and growers. Percentage losses are reported only where the writer had
"reason to believe that sufficient information was at hand to make the re-
port reasonably accurate.
The identity of many of the fungi was either determined or eewened?
by Dr. Leland Shanor on the basis of material forwarded him by the writer.
‘VEGETABLE CROPS
ASPARAGUS OFFICINALIS, ASPARAGUS. pewmiosnens asparagi was abundant on
the stems of 70% of the plants in one field.
BRASSICA CAIPESTRIS, RUTABAGA. Boron deficiency was found to be caus-
ing considerable loss in one locality in western Virginia. In this local-
ity from 5CO to 6CO acres of rutabagas are produced annually to be mar-
keted in late August and early September. In 1943 approximately 10%
(estimate by the dealer and by the County Agricultural Agent) of the acre-
age suffered from boron deficiency. This represented practically a 10%
market loss since no means of removing all affected roots from a lot was
known, hence Begs from affected fields were not marketed.
BRASSTICA CLERACEA var. BOTRYTIS, BROCCOLI. Peronospora parasitica
(downy Eigen was observed on most of the older leaves in two fields.
Mosaic was present as a trace in one field.
BRASSICA CLERACBA var. CAPITATA, CABBAGE. Alternaria circinans (A.
brassicae) was very prevalent in western Virginia. This infection devel-
oped late in the season so that appreciable loss is doubted. It was
observed in one field in eastern Virginia. Fusarium oxysporivm f. con-
glutinans (yellows) was of rare occurrence. in one large field approxi-
mately 30% of the plants had been affected. Peronospora parasitica (downy
mildew) was found on cabbage leaves in several fields but was causing
little loss. Xanthomonas campestris (black rot) was found as a trace in
one Tield.
CAPSICUL: FRUTESCENS, PEPPER. Pseudomonas solanacearum was suspected
to be the cause of death of several rf piants in one field. liosaic (virus)
Was observed in several fields, different sections of one field varying
from 2 to 20% of the plants affected.
234
_ CUCURBITA PEPO var. CONDENSA, SUMMER SQUASH. Erysiphe cichoracearum =
fades aed tee was observed as.a trace in one field. _Pseudoperono- e
spora cubensis (downy mildew) was observed in one field, but appeared to
have caused little loss. 3
DAUCUS CARCTA, CARROT. Alternaria carotae (leaf blight) was observed %
in many gardens. All specimens examined microscopically yielded this
fungus.
IPOMOEA BATATAS, SWEETPOTATO. Actinomyces ipomoeae (pox) was observed
occasionally as causing little damage. Fusarium sp. (blue stem) had S
caused a moderate loss in yield in one field. Stem infection was severe 3
in this field. Monilochaetes infuscans (scurf) had affected at least 15%
of the roots in one field and was general in other fields. Phyllosticta 3
batatas (leaf spot) was abundant, but seemed to be causing little damage.
Rhizopus nigricans (soft rot) was causing a follow-up rot in many roots 3
affected with blue stem. Z
LYCOPERSICON SSCULENTUM, TCMATO.-
Alternaria solani (early blight) was severe in all early-planted fields,
leaf spots having ving caused from 50 to 90% defoliation when harvest was ap-
proximately two-thirds completed. The yeild loss probably approached 10%.
Fusarium oxysporium f. lycoversici (wilt) was a major disease in eastern
Virginia. Here the Rutgers varity is used widely. However, the frequent
occurrence of varietal mixtures made it difficult to correlate the wilt
positively with the Rutgers variety.
Phytophthora infestans (late blight) was distributed widely in south- _
western Virginia. Both leaves and fruits were affected, though the fruit ~
rot aes was seen more commonly. The highest infection observed was one
of 10% of the fruit and 2% of the leaves. :
Phytophthora parasitica (buckeye rot) was observed much more rarely -
than the late blight rot and appeared to have caused little loss. ;
Sclerotium rolfsii (southern blight) was an important cause of loss in
eastern Virginia. Losses ranged from 3 to 80% of the plants (Parris).
Septoria lycopersici (leaf spot) was much less damaging than the Alter- —
naria spot throughout the State.
_ Mosaic (virus)-infected plants were observed in many eiaiiee in a few
fields a high percentage of the plants were infected. In one field both =
the common tobacco strain and cucumber mosaic were abundant. By October
. these virusés. oe spread until most of the plants showed symptoms of both
ais stetace :
Blossom-end rot pies ok a affected csiemond 5% of the crop. in
* western. cae
a a ee LF Oe eee ae
PET2OS@LINU CRIS PUM, PARSLEY
Heterodera marioni (rootknot) had caused about 10% loss in one field
of young parsley plants. . |
PHASECLUS VULGARIS, BEAN. | . 4
Bacterial blight (specific type not determined) was observed occasional-
ly, in no case was it observed to be causing measurable lass. a
Colietotrichum lindemuthianum (anthracnose) was observed in all vortions |
of the State, but was causing heavy loss in only a few small suiewiceen:.} in a
western Virginia. ae
235
Paepekohe polyvsoni (powdery mildew) was found as a trace in many fields.
In one 6-acre field all leaves and seme of the remaining pods were at-
tacked heavily. However, loss was slight as most of the crop had been
harvested before the infection became severe. Loss for the state was
negligible.
Uromyces phaseoli var. typica frist) was common in home plantings,
usually Deine more severe on unnamed home grown varieties. It was pre-
sent as a trace in several commercial plantings.
Bagucict (Heterodera marioni) was of general occurrence, in one field
being responsible largely | for. a yeild.difference of 50 bushels as com-
pared with 3CO bushels per acre in 2 fields on the same farn.
_ Mosaic (virus) was frequently seen, affecting as high as 5% of the plants
in some fields. Oarlie
SOLANUM HELONGENA,-EGGPLANT. Fusarium sp. (wilt) had caused vascular
discolorations in 5C% of the plants in one field, many of these plants
being wilted. Phomopsis vexans (fruit rot) was present on nearly 50% of
the fruits in one field in n October, the owner estimating a loss of about
25% from this cause during the season.
SOLANU: TUBEROSUM, POTATO. Phytophthora infestans (late blight) was
observed as a trace in a very few of the fields observed. The mountain-
ous area in the 5 western counties was not visited. Leaf roll, mosaic,
and spindle tuber (virus) were prevalent and causing yield reduction in
eastern Virginia. In one field a few plants were seen which showed symp-
toms typical of yellow dwarf.
SPINACIA OLERACEA, SPINACH. Peronospora effusa (downy mildew) had not
developed in eastern Virginia at the end of October. Reports received
-from this section indicate that in November a moderate infection of this
disease ee ee
CEREAL AND FORAGE CROPS
SOJA MAX, SOYBEAN... Alternaria Spe, Cercospora sojina, and Phyllosticta
glycineum were ider.tified from material collected in a field suffering
severely from leaf spots in eastern Virginia. Xantnomonas phaseoli var.
sojense (bacterial pustule) was observed on soybeans in all sections of
Virginia. In most cases the loss was considered to be slight.
SORGHUL VULGARE, SORGHUM. Helminthosporium turcicum was prevalent in
':-a field in eastern Virginia.
TRITICUM AESTIVUM, .WHEAT. Puccinia~graminis: tritici.{stem rust), on
the basis. of .straw stacks seen and onthe reports of growers, was very
- severe. in sections - of western Virginia. Yields as low as 5 bushels per
acre were reperted;: Se Se ame mostly to the attacks of stem rust.
VIGNA SINENSIS, COVP Amerosporiun oeconomieun -( Leaf. spot.) was abun- -
_ dant in one field Pa in southeastern Virginia.
ZEA MAYS,- FSELD -CGRN. Helminthosporium maydis was identified By Drs
ek es oe.
“aa Leland Shanor from leaf lesions collected in southeastern Virginia. Hel-
__ minthosporium turcicum was. identified as the cause of a larger leaf lesion
gin, the. same field. The total injury ed by coe unss Sarre eax
Dain ean Midi seas Se ee aid ik
236
FRUIT CROPS
AMYGDALUS PERSICA, PEACH. Monilinia fructicola (brown rot) was of
extremely rare occurrence. Yellows (virus) was observed as affecting
a few trees in northern Virginia. One affected tree was observed near
Hansonville in southwestern Virginia. Drought during midsummer tended
to reduce the size of the fruit and was an important faetor in reducing
losses caused by brown rot. Frost during the spring caused complete
destruction of the crop in many orchards and was responsible for a very
light crop in the State.
MALUS SYLVESTRIS, APPLE. Corticium galactinum (white root rot) was
tentatively diagnosed as the cause of death of two trees examined. Er-
winia amylovora (fire blight) was much less abundant than during the _
past few years. Glomerella cingulata (bitter rot) had affected approxi-
mately 10% of the Grimes Golden apples in a close-planted, poorly-sprayed
block. It was seen in no other orchard. Gymnosporangium juniperi-vir-
ginianae (rust) was observed in many apple orchards. It ranged from
slight to severe leaf infections, in a few instances having caused suf-
ficient defoliation to have reduced the fruit size. Physalospora obtusa
(black rot) was observed as a trace in a few orchards. Venturia inaequa-
lis (scab) caused a considerable loss in unsprayed or poorly-sprayed
orchards, but was unimportant in well-sprayed orchards. Xylaria mali
(black root rot) was found to be killing trees in 4 of 6 3-to 13-year
orchards examined in Clark and Frederick Counties. A total of 16 trees
of approximately 526C had been killed by this disease. In older orchards,
in which no accurate check was made, a number of trees were killed by
this organism. ;
PRUNUS CERASUS, CHERRY, SOCUR.. Coccomyces hiemalis (leaf.spot) develop-
ed rapidly during June; but. the following drought checked the epiphytotic,
loss being less than in recent years. Dibotryon morbosum (black knot)
was observed as severely damaging one small tree in a home garden in
Washington County. Monilinia fructicola (brown rot) was of little impor-
tance in 193. : :
VITIS SP., GRAPE. Cercospora viticola was found in abundance in one
location in western Virginia. Guignardia bidwellii (black rot) was very
destructive throughout the State. | |
SPECIAL CROPS
ARACHIS HYPOGAEA, PEANUT.
Mycosphaerella arachidicola was the cause of the leaf spot collected
in August, while M. berkeleyi was the most abundant species on collections
in the same areas in October. In the opinion of those familiar with the
problem, infection and loss was somewhat less than in recent seasons.
Sclerotium rolfsii (southern blight) killed few entire plants in most
fields, the number being less than 5% in any field seen. However, in
some fields, which at first glance showed little death of plants, many
plants were found to have one or two dead stems.
In company with Dr. S. A. Wingard, 3 days were spent in examining pea-
nuts at harvest time. Mr. E. T. Batten, Superintendent of the Holland |
237
Station, estimated that approximately 30% of the peanuts of proper matur-
ity in that scction were rotted, the rot ranging from 5 to 50% in dif-
ferent fields. Accurate counts were difficult because of the tendency
.of the rotted nuts to be lost in digging. The incidence’ of rot was cor-
_ .related with crop rotation, being more extensive where peanuts followed
peanuts than in fields not recently planted to peanuts or to other sus-
ceptibie crops. In general, rot was more severe on plants of which some
stems hed been killed than on plants that showed no wilt.
At the Holland Experiment Station adjacent plots of peanuts following
peanuts and peanuts following soybeans were examined. Immediately after
digging (aechanical) the pods from 4 consecutive plants in each plot were
opened and the condition of the nuts recorded. While these counts are
of limited extent, the plants examined appeared representative of the
plots. The data are presented in Tabie l.
Table 1. Effect of rotation on rot of peanuts.
Peanuts following
Pesmits _ ocyoesns
Attached Loose* Attached Loose
_to vine in soil to vine im soil
Pods very immature g = 10
3
Pods sl. immature, probably usable 15 2 29 a
Pods mature, nuts sound | 5 1 36 A:
Pods over-mature, nuts sound 1 14 7 4.
.Mature to over-mature, nuts rotted:
_ Scierotium rolfsii 13 14 17 8
shrivelled, prob. Sc. rolfsii 13 | 12 2 i
; miscellancous rots. _ Ly yee: 3 1
_ Harvested crop:
sound | 21 (277 £38) -- 72 (4) (76)
motied: ) 30 ri (50): ~ 22 (16) (38)
* Pods lost in normal digging operations
The rot of’ pcanut pods was due principally to Sclerotium rolfsii. Of
the several samples ccllected from various fields, microscopical examina-
tion by Dr. iingard revealed that a low percentage of the pods centained
feusbing structures of Thielavia, Penicii. aus Rhizopus, and other sgh
ee GOSSYPIU:, CCTICN. Alternaria gossypina (leat spot) was very abundant.
Fusarium moniliforme (boll -x rot) was. present on less than 1% of the bolls
_-ingone fietd. fanta thomonas malvacearum (angular leaf spot) was abundant.
-- NECOTIANA TABACUM, TCBACCO
. This section has been abbreviated from a report prepared for the writer
-sby Dr. i. A. Jenkins of the Tobacco Experiment Station at Chatham.
~ Peronospora tabacina (downy.mildew) caused individual plant bed losses
anging from negligible to 90%; average losses ranging between 25 and 10%.
239
The sustained epiphytotic contributed to the late planting of at least
1/3 of the tobacco acreage in Virginia and to severe losses later in the
season (PDR 27:298, 1943). —
Phytophthora parasitica var. nicotianae (black shank) was seen on
several farms in Pittsylvania, Halifax, Charlotte, Franklin, and Mecklen-
burg Counties from which there had been no reports of the disease in pre-
vious seasons. In only a few instances did the infestations appear to
have been of recent origin.
Pseudomonas solanacearum (Granville Wilt) continued to. spréad local-
ly in both the bright and dark fire-cured belts. Losses ranged froma
few plants to as high as 70% of the plants in some fields.
Rhizoctcnia solani (sore shin) was general throughout the bright tobac-
co belt. In most cases the total loss was negligible. In Patrick County
severe losses were reported locally.
Sclerotium rolfsii (southern blight) was seen in only a field or two
in Pittsylvania County. %
Thielaviopsis basicola (black root rot) was observed fairly generally
throughout the area. Owing to the late season and the use of resistant
varieties in the bright tobacco belt, the disease caused little notice-
able damage except locally. _
Heterodera marioni (rootknot) was present and appeared to be spreading
slowly in certain sections of Pittsylvania, Halifax, and Dinwiddie Coun-
ties.
Brown root rot (cause undetermined) was found on 2 farms in Halifax
County.
Mosaic (virus) was general throughout the tobacco area, field infec-
tions ranging from 10 to 90%.
Ring spot (virus) was scattered, though on the increase in the =
tobacco belt. Losses probably were insignificant.
"Ruffle leaf" (probably genetic anomaly) was found in a single field
in Franklin County during the season. Essentially every plant in this
field was affected and the crop was rendered unfit for harvest.
MISCELLANEOUS CROPS
TPOMOBA HEDERACKA , Albugo ipomoeae-panduranae (white
rust) was abundant in immediate proximity to sweetpotato fields.
TPOMOHKA PURPUREA, WILD MCRNING GLORY. Albugo ipomoeae-panduranae
(white rust) was abundant in immediate proximity to sweetpotato fields.
Coleosporium ipomoeae (rust) was observed frequently. Cercospora viridula
(leaf spot) was collected in western Virginia.
PINUS STROBUS, WHITE PINE. Chlorotic dwarf (cause unknown) was diag-
nosed tentatively as the cause of chlorosis and dwarfing of a few trans-
planted white pines in gardens in Biacksburg.
Needle blight (probably nonparasitic) affected many white pines in Floyd
and i Jontgomery Counties. Early in the season this injury was diagnosed
by Dr. S. A. ‘Jingard as being caused by the death of feeding roots due to
excessively high soil moistures. A similar trouble is described in more
detail in the summary for West Virginia.
PRUNUS SEROTINA, WILD BLACK CHERRY. Phyllosticta prunicola (leaf eS
wes abundant in two locations in eastern Virginia. Tranzschelia pruni-
spinosae (rust) was abundant at one location in eastern Virzinia.
_
239
EMERGENCY PLANT DISEASE SURVEY IN WEST VIRGINIA IN 1943
Carlton F, Taylor
Work on the Emergency Plant Disease Prevention Project was started in
West Virginia July 27, 1943. While many crops had been harvested at that
time, the writer had been in a position to observe diseases in portions
of the State during the carly season. During the remainder of the season
an attempt was made to visit each crop region at least once at a time
Suitable for examination of the most common crops grown.
Data on cereal crop diseases were obtained from Mr. William Watson, in
charge of the Barberry Eradication program in West Virginia; the source
of such data are indicated in the text. Members of the Department of Plant
Pathology made available other data on crop loss.
Following ere the observations on plant diseases in West Virginia in
39,3;
VEGETABLES
BETA VULGARIS, BEET. Cercospora beticola (leaf spot) was prevalent
throughout the State but appeared to cause little loss. Nematode (un-
identificd) was the probable cause of galls on a specimen submitted to
the Experiment Station for diagnosis.
BETA VULGARIS var. CICLA, SWISS GHsRD. Cercospora beticola (leaf spot)
caused the discard of more than 50% of the leaves in many plantings.
BRASSICA OLERACEA var. CAPITATA, CABBAGE. Fusarium oxysporum f. con-
glutinans (yellows) was observed on few plants. The use of wilt-resistant
varieties is general in West Virginia. Plasmodiophora brassicae (club
root) was found in one garden in Morgantown.
BRASSICA RAPA, TURNIP. Phyliosticta tabifica (leaf spot) was abundent
in gardens in two sections cf the State.
CUCULIES SATIVUS, CUCUMBER. Colletotrichum lagenarium (anthracnose)
killed the vines in a greenhouse planting; this developed aftcr a normal
crop had been harvested, so probably caused little loss. Many garden
plantings in Monongalia County were killed by this disease.
DAUCUS CAkCTA, CARROT. Alternaria carotae (leaf blight) was widely dis-
tributed. A reduction in yield of 5% is estimated.
LYCOPERSTCO! ESCULENTUM, TOMATO. alternaria solani (carly blight) was
--general throughout West Virginia. It was estimated that 40% of all tomato
foliage in the State was killed by this disease. Many ficlds were de-
foliated in carly stages of production.
Cladosporium fulvum (leaf mold) was found in two locations in gardens
_ with very poor air drainage. Where observed the percentage of infection
was high. It is assumed that some loss in yield was incurred.
Fusarium oxysporum f. lycopersici (wilt) caused extensive loss in plant-
ings of non-resistant Le ena , mostly in novelty-type varicties.
Phytoohthora infestans (iete blight) was of major importance in the
' mountainous districts. In some plantings all of the leaves had been killed
end 2/3 of Ee fruit had rotted by early September. In Pocahontas County
250
a was estimated that a crop loss af 25% was caused oe ys Nene Bip
is estimated that the loss for the State was not more than 2%.
Phytophthora parasitica (buckeye rot) was much less abundant than late
blight. In adjacent Victory gardens with unstaked plants of the saine
variety and age, heavily straw-mulched vines had no rotted fruits in .
September, while unmulched plants had 44% of the fruits rotted by this
organism, . .
Septoria lycopersici (leaf spot) was found frequently but caused severe
loss in few fields. Over the entire State it caused not morc than 1/5 as
much leaf destruction as did Alternaria. :
Nematode (probably Heterodera marioni) was observed to be sogen ta af-
fecting all tomato plants in a garden in Logan. | 4
Mosaic (virus) was’rare in most plantings. In one planting of 1000:
plants all plants were affected severely and production was negligible. -
In garden plantings the incidence of mosaic varied from O to 25%. In one
greenhouse mosaic apparently was contracted from adjacent petunias, neces-
sitating the discard of a lot of experimental plants. The ess for the
State due to mosaic probably was not more than 1%.
Tip blight (virus) was present in the greenhouse where discovered in
1942, but in very much reduced amounts. A clean-up campaign was Cenueee
sible for this reduction,
Blossom end rot (non-parasitic) caused severe losses in the drought-
affected commercial areas in the eastern part of the State. Counts of af-
fected fruits ranged as high as 02%, The loss for that section was esti-
-mated at from 15 to 20%. A state-wide loss of 10% was estimated.
Lightning killed all of the plants in a small area in one field.
-PHASEOLUS LUHATUS, LIMA BEAN. Bacterial blights were observed in sever-
al plantings, but appeared to have caused little damage.
Phytophthora phaseoti (downy mildew) was present on approxinately 15% a
of the pods in one semi-commercial garden in mid-September. Ffosaic symp-
toms were present on 5% of the plants in a commercial field.
PHASEOLUS VULGARIS, BEAN. Colletotrichum lindemuthianum (anthracnose)
was not found in most of the gardens examined. In a few gardens the loss —
approached 100%. In most cases it appeared that the source of inoculum a
lay in rows planted to home-grown seed. 2
Fusarium sp. (root rot) killed as high as 20% of the plants in ccpesen 4
gardens in the vicinity of Morgantown, No observations were made on the a
prevaience of this disease throughout the State.
Pseudomonas medicaginis var. phaseolicola and Xanthomonas pha haseoli 5;
(bacterial blights) rarely were observed to have caused appreciable loss a
and in most cases could be traced to the use of home-grown seed. In one sg
large garden all of the leaves and 5% of the pods were infected on Septem-
ber 8, “
Uromyces phaseoli var. typica (rust) was observed in several localities, i
but had caused appreciable defo defoliation in only one or two cases.
_ SCLANUM TUBEROSUM, POTATO. Actinomyces scabies (scab) appeared more >
prevalent than in past seasons. Several cases of very severe loss (more ‘
than 50% of sri inarket value of the crop) were encountered. This appeal ——
2h
Alternaria solani (early blight) was prevalent on early maturing varie-
ties in the lower portions of the State. In the mountainous regions it
was less damaging because, if the potatoes were not protected by sprays,
late blight killed the foliage in advance of the early blight. A loss of
6% for the State was estimated. -
Corynebacterium sepedonicum (ring rot) was observed in several lots of
harvested. tubers..
Erwinia carotovora (bacterial soft rot) was the probable cause of the
loss of as many as 5% of the tubers in several fields. Usually this dis-
ease was correlated with excessive injury from the wheels of the potato
spray machinery.
Pellicularia filamentosa (Corticium solani) (rhizoctonosis) was not
studied in relation to. sprout injury in the spring. Sclerotia were. ob-
served on the tubers in a few fields, 37% of the tubers affected being the
most severe infestation noted. In this field 4% of the tubers were pitted,
these pits resembling those typical of insect injuries followed by Rhi-
‘zoctonia.
Phytophthora infestans . (late blight) caused reductions in yield of more
than Og in unsprayed or poorly sprayed fields. Most of the loss was due
to reduced tuber size due to foliage loss. Tuber rot was slight owing to
to the very dry weather preceding and during the harvest period. The total
loss in yield for the State was estimated at 17%. During early August at
the height of the epiphytotic, unsprayed fields were observed to have pro-
gressed from one or two focal points of infection to destruction of 80% of
the foliage in from 8 tc 10 days,
Pythium sp. was suspected of being the cause of "leak" observed in many
fields at harvest time. The maximum infection noted was not more than 2 or
3%, the loss for the State being negligible.
Spondylociadium atrovirens (silver scurf) was observed on the tubers from
many fields. Infection was ‘slight and it is believed that this disease
caused no reduction in market value.
Bluestem (virus) was less sever re than in 1940 and 1941. A loss of 3%
was estimated.
Spindle tuber (virus) symptoms were observed in several lots of harvest-
ed tubers, in one lot approximately 10% being affected.
Virus diseases such as mosaic, leaf roll, and others were observed in
many fields, During the season of this survey the plants had passed the
optimum period for the diagnosis of such diseases.
Hooper burn (leaf hopper) caused heavy loss in production in the same
areas affected by a blight. A loss of yield of 6% for the State was
estimated.
CEREALS, GRASSES, AND FORAGE CROPS
AVENA SATIVA, OAT. Puccinia coronata (crown rust) caused an estimated
loss in yield of 2% (Watson). Pucciria praminis var. avenae (stem rust)
was estimated as causing a loss of ie 5%.
Ustilago avenae (loose smut). Data were taken by the writer on plots
from 32 samples of oats taken from farmers! grain drills and planted at an
experiment station. The smut counts showed a range of from O to 18%,
ere >
: AR:
ot)
pi wsite
_ was very much less severe than in 1942. Ustilago maydis (U. zeae) (smut)
o> RE ORS ee Soe rao ena ce eae
— <a _ re ae oe ae (4 Sa
Ie = ye ae:
22a et
we Stan re
21,2
averaging 3.98%. Only one sample yielded a positive test for the presence _
of a seed treatment. It is believed that these data are representative —
of the State. : : . ure
HORDEUM VULGARE, BARLEY. Gibberella zeae (scab) was reported as a 4A
loss, approximately half as destructive as in 1942. Puccinia anomala *
(leaf rust) was reported as a loss of 1% (Watson). Puccinia graminis var.
tritici (stem rust) was reported as a trace (Watson). Ustilago sp. (loose ‘
smut) was estimated to have caused a loss of 3%.
POA PRATENSIS, BLUE GRASS. Ustilago striaeformis (smut) on the basis ‘
of information made available by J. G. Leach ard others, affected as ee
as 25% of the plants in some pastures.
SECALE CEREALE, RYE. Claviceps purpurea (ergot) was seaseeed ina Page ‘
fields, :
SOJA MAX, SCYBEAN. Xanthomonas phaseoli var. sojunee (bacterial pustule) :
was observed in most sections of the State, but in no case did it appear
to be causing appreciable damage. |
SORGHUM VULGARE, SORGHUM, = Puccinia purpurea was found on the —
leaves in one planting. a “
TRITICUM AESTIVUM, WHEAT. Gibberella zeae (scab) was less severe than ?
in 1942 but was estimated as causing a loss of about 4%. Puccinia grami-
nis var. tritici (stem rust) was prevalent in the southeastern part of
the State where the native barberry is abundant. The loss due to this
* disease in West Virginia in 1943 was estimated at between 10 and 15% 4
(Watson). Puccinia rubigo-vera var. tritici (leaf rust) was estimated as ;
causing a loss of approximately 1% (Watson). Ustilago tritici (loose
smut) was estimated as causing a loss of 3%.
ZEA MAYS, FIELD CORN. Helminthosporium turcicum (leaf blight) was ob-
served to be causing severe leaf injury in but 4 of all corn fields within
view of the roads travelled in the course of this survey. This disease
le nS et
was present in most of the fields, but usually Besos a low percentage
of the ears.
FRUIT
AMYGDALUS COiMUNIS, ALMOND. One tree in Brook County, the ‘only almond
tree observed, showed advanced symptoms of yellows (virus). a
AMYGDALUS PERSICA, PEACH. Monilinia fructicola (Brown rot) caused minor ce
loss, probably due to. dry weather at harvest time. Virus yellows is 4
widespread on non-commercial plantings, an estimated 20 of such trees
being affected. In commercial orchards the loss was much less than 1% of
the trees, Frost killing of the buds reduced the crop by at least 50%.
AMYGDALUS PERSICA var. NECTARINA (NECTARINE). One tree in Jefferson
County shoved symptoms of yellows (virus). This was the only nectarine
tree seen. a na
MALUS SYLVESTRIS, APPLE. Armillaria mellea was considered responsible
for the death of 4 of 245 dead trees in the 3- to l4-year age class. .
Erwinia. amylovora (fire blight) was much less severe than in recent years.
Gloeodes pomigena (sooty blotch) was abundant on fruit from unsprayed)= a
orchards. }
a nunii ail
aS ae. ae Pa 4 |
: eh
Glomerella cinzulata (bitter rot) was rarely seen in the drought-affec-
ted eastern portion n of the State. . In the Chio Lege i one count of 60%
infected fruit was obtained; many trees reached 20% infected fruit.
These were isolated cases and the loss for the State as a whole was negli-~
Pape, .
2 PS ae a Jue eras (cedar-apple rust) was more preva-
dent than during recent years. Leaf infections caused a considerable
amount of premature deral ee in some orcnards, in a few cases this
condition being agsravated by spray injury initiated in the rust lesions.
In one Rome Beauty orchard 20% of the fruit was reduced in grade from U.S.
No. 1 to No. 1 Canner, a few with very deep lesions being graded as cider
apples. iittle fruit. infection was seen in most orchards.
Helmintnososorium panulosym (black pox) was found in unsprayed orchards.
Jliosyorara nei foliorun (leaf spot} was observed in abundance in an
unsoraved or cnecd.
Leptothyrivm pomi (fly speck) was abundant on fruit from unsprayed
orerarcis:, ;
Mycosphaerella pom {fruit soot) was found rarely.
Pay: lcesticua s Solitaria (blotch) was rarely found in the dry eastern
portion of the: State. Where rainfall was more esbundant it was found on
susceptible varieties. Mighty per cent of the fruit were infected on one
Gane tree an-the Ohio Valley.
Phvsalosnora, obtusa caused very es ioss in sprayed orchards.
-Phrto “opnehore, ce cactorum (crown rot} was tentatively diagnosed as the
cause of death of more than 1OCO ee to 10-year-old trees. It was first
called to the attention of Dr. A. B. Groves cf the Winchcstcr Rescarch
Laboratory by a grower who lost more than 50C trees from this disease.
Venturia aia inaequalis (s cab) was much more prevalent than during recent
seasons. The less was more severe in the western than in the eastern por-
tion of the State; many pcorly sprayed orchards being defoiiated by mid-
summer due to scab. The loss due to scab was estimated at 16.4% (12% yield
and k.4% quality).
Xylaria mali (black root rot) appeared to be more prevalent than during
Feeen. years, his was assumed to be an effect of drought, less: loss of
root system peing tclerated than in normel years. It is probable that a
tendency to visit orcherds where tree loss had been reported in t hose
cases where »rior inrcrmation was availeble provided en upward bias in the
estimates of tree loss for the area.
Bitter pit (non-parasitic) was present in many orchards, occasionally
causing scvere loss. The loss for the State probably wes lower than 1%.
Internal bark necrosis (non-parasitic) was found occasionally, but was
of minor importance.
Frost injury on the night of lay 1 reduced the crop by about 40% in the
eastern part of tne State and by approximately S04 in the remainder of
the State.
a OP) VY on re Seeley ta. dh 2h ey . wo 3 BATS So age oe eee! hte ae cr eae Le
; F, rd
2h),
-PRUNUS spp., CHERRY, SOUR AND SWEET. Coccomyces hiemalis (leaf spot)
was mach less severe than in recent years in the dry eastern portion of
the State. Here unsprayed vewide were only partially defoliated at
the end of the seascn in contrast to recent years when unsprayed trees
were defoliated in Weahee sie oh Leaf spot was severe in other portions
of the State. Monilinia fructicola (brown rot) was of minor importance
in 1943. . prea Ne
RUBUS spe, RASPBERRY. Elsinoé veneta (anthracnose) was found on speci-
mens submitted to the 2 aoa Station by a County Agricultural Agent.
Mosaic (virus) was seen frequently but no data were coliected on,its preva-
lence.
ViTIS sp., GRAPH. Guisnar dia bidwell: can (black rot) probably caused
the destruction of weil “over 50% of. vhis fruit in 194.3. Losses of 30%
were common in unsprayed plantings. Plasmopora viticole (downy mildew)
infected 100% of the leaves in many plantings and, in some cases, caused
a 50% defoliation by late September. Yield loss was slight since most of
the grepes in these plantings had been destroyed by black rot. Uncinula
ator (f oe mildew) was present on many of the leaves in one vineyard.
TREES
PINUS STROBUS, WEITE PINE. Needle blight (probably non-parasitic).
In June of 1°42 the writer had occasion to examine a few hundred acres
or white pine forest (natural stand) in whica a die-back of needles was
prevalent. The svmotoms agreed ciosely with those later described by
Spaulding and Hansbrough (Spaulding, Perley, end Hansbrough, J. Re The
needle bliignt of eastern white pine. Mimeographed report issued by the
Division of Forest Patnology, Feoruary, 1943. Two pages). Needle tips
were a reddisn-brown and the affected parts appeared to be dead. At that
time it was suggested that this was a drought effect. With the advent of
heavy rains new growth developed, these new needles remaining in excellent
condition throughout 1943. Tne needles affected in 1942 dropped during
the winter of 1942-H3. :
In 1943, during an excessively wet spring, similar foliar symptoms de-
veloped. In :Jest Virginia affected pines were observed in most sections
where tnc white pine occurs naturally. Cn most trees all needles were af-
fected severely, or other trees the injury was confined to the leaf tips
cn portions of the tree. During the period from mid-July to late Cctober
no noticeable change occurred in the appearance of the affected trees. A
similer injury in Virginia was noted bv Dr. S. A. Wingard of the Virginia
Agricultural Jixperiment Station and diagnosed as being caused by the de-
struction of rootlets in saturated soil moistures. Large numbers of pines
were affectcd in easter: West Virginia. No data are available as yet on
the survival of trees iffected in 19/43.
Chlorotic dwarf (cause unknown) was diagnosed by May and Swinge of the
Division or Forest Patnology %s the cause of stunting of white pines in
two plantings in West Virginia.
QUERCUS ALBA, (WHITE OAK). Many meture white oak trees were killed by
an unidentified trouble in southern West Virginia in 1943. Beyond the fact
that the two-lined chestnut borer was present in the affected trees, no
diagnostic data were obtained in a brief survey. Arrangements were made
to revisit the area in 1944 in company with forest pathologists if the
‘disease! reappears. .
215
(eae KENTUCKY PLANT DISEASE SURVEY, 1943
R, A. Hyre
The following is a summary of surveys made in September. Credit is due
Dr. Valleau and his staff for assistance in identification of specimens.
. VEGETABLE CRCPS
i
IPCMOFA BATATAS, SWEETPCTATO
Twenty-two fields were examined carefully, centering around Graves County
in western kentucky and Jefferson County (Louisville ) in north-central
Kentucky. The fields varied from 1 to 5 acres in size with one 10-acre
field included... The variety was largely Nancy Hall.
(Fusariua oxysporum f. batatas (F. batatatis and F. hyperoxysporum) stem
rot, was virtuelly the only disease encountered. The loss varicd from
about 20% in lower western Kentucky to about 10% around Louisville. One
-feld each at Lexington and Hopkinsville was free from stem rot while about
5% was present in one field each in McCracken, Todd, and Warren Counties.
In 2 fields examined the Porto Rico variety had from 1/3 to 1/5 as much
“stem rot as Narcy Halls in the same ficlds. In 2 acres of Maryland Golden
a trace of stem rot was found while ediacent Nancy Halls had 10%.
Endoconidionhora (Ceratostonuella) fimrrieta, black rot. Harvested pota-
toes were scsen on only one farm in Jefferson ‘County, and e trece of black
rot was preseit there. .
Mosaic (virus) was seen only in Todd County where 0.5% occurred in 1-1/2) .
acres. |
LYCOPERSICON ESCULE"TUM, TOMATC,
Eleven fields, averaging 3 to 4 acres each, were examined in the western
half of the'State. Severe drought conditions injured the crop.
£lverneria solani, early biignt, owine to dry weather, was unimportant ex-
cept in the single field examined in Warren County which was 50% defoliated.
Bacillus sp., soft rot was of iittle importence except in some cases
where it fclicwed and destroyed fruit alreadv damaged by sun scald.
uses ve ne Digs Sey See pee GODT SI EL. wets was oer in 33 Be HP 11 fields.
a trace in cne field in ipeb ice nee
Colletotrishum phomoices, anthracnose, was found only in the 2 fields
surveyed near Lexington (Fayette County) but caused little loss.
_ Sun scald. The-tomato plants were not staked and with sparse foliage
' resulting from the drought sun scaic of the fruit was almost universally
: present and severe. For example, the crop on 7 acres in. Hancock County was
_ almost a wotal loss from sun scaid since the farmer could not afford to
hire the tomatoes picked and haul them to the factory because of the low
a price offered by the camiery.
26
CEREAL CROPS
SORGHUM VULGARE, SCRGHUM
Cexcospore sorghi (?). A purple leaf spot was very general in and
around Harian County.
ZEA MAYS, MATZE (INDIAN CORN) rm
Twenty fields of corn were examined, covering the State. A severe
drought in the western part of the State curtailed the survey.
Bacterium stewartii, bacterial wilt. The late infection, or pacuseses
leaf bligit, was found in all fields examined, varying from 15 to 85% of
the plants affected. The actual leaf area killed generally was estimated
to be about 5 to 10%, occasionally reaching as much as 20 to 25% from
all leaf diseases of which bacterial wilt was dominant in all areas ex-
cept around Harlan and Letcher Counties in eastern Kentucky, and was
frequently the sole leaf disease preserit in western Kentucky.
_ Cercospora zeae-maydis, leaf spot, was the dominat leaf disease in
Harien and Letcner Counties. This disease was not known to occur in
Kentucky prior to this survey.
Fusariun moniliforme, ear rot,-was frequently found following ear worm
injury but the damage was slight. So few ear rots of any kind were found
that tne survey was discontinued.
Helminthosporivm spp. were found most frequently in the eastern part of
the state but were much less abundant than bacterial leaf blight.
Puccinia sorghi, rust, was recorded to the extent of 3% of plants af-
fected in “just one feria:
Us tilago maydis (U. zeae), smut, was found to the extent of 3% of plants
affected in gluse 2) ieldss
Firing i A firing and drought injury of the leaves was so abundant in
western Kertucky that it rendered the surveying of leaf diseases diffi-
cult.
FRUIT CROPS
AMYGDALUS PERSiCA, PEACH
Three orcnerds were examined. The crop was almost eliminated by spring
freezes. :
Xanthomonas pruni, bacterial spot. In a McCracken County orchard bac-
terial leaf spot was general but not severe.
Spray injury. Ina Livingston County orchard marginal spray injury of
the Red Bird variety was severe.
MALUS SYLVESTRIS, APPLE
Fifteen orchards were visited. Many of them were along the Ohio River.
A late spring freeze misled many growers as to their probable crop and,
as a result, tne spraying suffered.
| Benoa eae information was obtained from Mr. W. D. Armstrong, Horti-
culturist, ‘Jestern Kentucky Experiment Station, Princeton.
Gloeoes pumgena, sooty blotch. The presence of sooty blotch in 4
small and one large orchard indicated the omission of some sprays.
OM ote fd NY ki ey an a oem Ly) tt uh) “ f oh
Patent E :
Al]
iaciied “peing severe in Sean aug Tn a ViGendenede County orchard a
cooper spray was not applied until bitter rot was already present and -then
it "kept.on coming". This, year diseases, Ts Sate ii bitter rot,. have
been a major factor in fruit production of the Grimes Golden, and Golden
Delicious varieties. The variety King David has nearly been eliminated
in Kentucky ly sitter: rot’.
Gymnosvoraugium clavines, quince rust, was causing concern and was general-
ly present, but not in great abundance.
Peptoonvr Lure pomi, fiy speck, was found.in the same 4 small orchards ,
and one large orchard in which sooty blotch was found.
pe Oost oa solitaria, blotch, was severe in one orchard each in
Christian, tjebsver, -, and Henderson. Counties and was present in Warren
Courity. . Jt wes seen im a severe form on the variety Arkansas Black, was
general on,.Grimnes Gclden, occtyrred on age Winesap, Maimnoth Black
Twig, and Stayman, and was oresent on Golden Delicious.
Phyiospora ‘obtusa, black rot, frog-eye Black rot of the fruit was
four. fro traces to considerable ancunis in 7 of the. U5 orchards. . The
frog-eye leaf spot caused considerable demage. sy
Venturia inaccualis, scab, was present in 13 of the 15 orchards sur-
veyed, and was severe on some varieties in 5 of them. In general it was
a bad scab year in Kenvucky, but the disease was fairly well controlled
in well-spraved orchards. In other orchards scab and codling moth did
not leave "enough apoies.for the second brood ef codling moth",
Arsenical injury of the calyx end was the main problem in one Henderson
County orchard. e
ae
SPECIAL CROPS
CANNABIS SATIVA, HEMP. Numerous fields observed from the car and a
few entered, but no diseases were noted. The stands were very irregular.
NICOTIANA TABACUM, TOBACCU. A summary of diseases on this crop, fur-
nished py iJ. D. Vallcau and E. M. Johnson, follows:
TOEACCO DISEASES IN KENTUCKY, 1943
7
We Dw. Valleat and he Ma Johnsen:
The plant bed season of 1943 was unusually wet. The worst outbreak of
wildrire [Pseudomonas tabaci] occurred in Central Kentucky in at least
the pest 25 4 years emphasizing the importance of protracted wet weather
in initiating an outbreak of this disease which has been comparatively
rare in Central Kentucky. Wildfire was found in avproximately 50% of un-
treated plant beds examined in Fayette and surrounding counties. The
severe outbreak of wildfire and angular leafspot [Pseudomonas angulata]
tested the value of the bordeaux treatment in preventing the diseases.
Kentucky Agricultural Experiment Station
248
Where applied early enough (before outbreak of the disease) bordeaux —
usually gave complete control throughout the plant bed season. An occa-
sional instance was seen where a few plants in a small spot in a treated
bed were infected, evidently in a spot missed in sprinkling. About 10%
of the beds were treated early enough to prevent infection and much treat-
ing was done after infection appeared. Although plant bed infection was
heavy, practically no wildfire or angular leafspot has been seen or re-
ported to us this summer except in areas of fairly high rainfall several
fields set from wildfire-infested beds appeared to be badly injured early in
the season,
Blue mold [downy mildew, Peronospora tabacina] was reported twice in
Central Kentucky (June 3 and 8) and from nowhere else in the State, al-
though it is probable that there was a light infection in other places.
_ At setting time there were 2 hot periods. On June 4, 5, and 6 tempera-
tures reached 92, 91 and 95° F; and on June 12, 13, 14, 15, and.16, maxi-
mums were 95, 96, 92, and 91° F. Stalks set June 4 were scalded, if the
_ plants were shanky, and most leaves were killed. By June 7 the plants looked
as though they might live although only the stalk and smallest leaves re-
mained. Tobacco reset that day, when the maximum temperature was 88° F
lived and grew rapidly; but rows not reset in the same plot continued to
die for several days;and plants surviving in these rows grew slowly as
compared with reset plants. In numerous fields throughout the State that
were set during or within 2 or 3 days prior to the hot periods stands were
poor and were not reset because plant died so gradually. Various reasons,
such as drouth and wire worms, were given for poor stands, but there
seems to be no doubt that the primary cause was the heat.
A drouth occurred over much of the State during July and August. Under
these conditions mosaic [virus] spread very slowly and suckers after cut-
ting showed unusually little mosaic. Kentucky 52 (NN) mosaic-resistant
burley, where used by farmers who have been troubled with mosaic, has
given perfect control. Kentucky 52 was of very high quality when cured.
Steak [virus] usually develops in burley tobacco in several counties
northwest, north, and northeast of Fayette County in July. This year there
was practically no streak during the drouth in July or August, but tobacco
still standing the second week in September following rain developed an
average of about 4C% streak in 14 fields examined in Owen County. Fields
along roadsides or waste places where sweetclover was growing showed heavy
infection (up to 100%); while fields surrounded by closely cropped pastures
or cultivated land were nearly free, It seems probable that infection oc-
curred during July and August when second year sweetclover died and in-
sects left it, but because of slow growth virus movement did not occur
until after September rains when translocation of food materials and virus
would be expected to be accelerated.
Black shank [Phytophthora parasitica var. nicotianae) was found in Wood-
ford, Carroll, and Bath Counties and in a new location in Scott County
higher up the Elkhorn Creek than previous outbreaks. In Bath County heavy
infection was found for more than a mile along Slate Creek. Sone was |
noticed in the creek bottom the previous year following a flood that cover-
ed some of the vlantings with water soon after setting. The trouble was
believed at that time to be.drowning. In 1942 infection was carried to a
ts
A Hae
(ht igs
ore
planting on a steep hillside about 300 yards up a draw from Slate Creek.
‘This field was heavily infected again in 1943, ard a planting on still
higher ground in newly plowed land set immediately after the hillside
plot was also heavily infected.
Fusarium wilt [Fusarium oxysporum f. nicotianae] seems to be on the in-
crease; at least we are receiving many more reports of it than in the
past. Kentucky 33 burley is being successfully used in infested areas;
an occasional. plant shows signs of infection but usually recovers. Wilt
was reported in Simpson County to be causing serious loss in fields of
One-Sucker dark tobacco.
Specimens of bacterial black stalk (Ky. Bul. 437) were received from
Marion, Fayette, Bath, Mason and Lewis Counties.
Potash starvation was prevalent in Burley tobacco. In spite of almost
ideal curing conditions following cutting, potash-starved tobacco appeared
to be curing poorly. Upper leaves were harsh, lifeless and very dark
brown.
Two cases of leaf spotting caused by phosphorus deficiency were observed,
in one instarice following a crop of vetch and rye turned under. In early
August the.older leaves of the small plants showed scattered necrotic
spots. The leaves had a very low phosphorus content and the addition in
the spring of superphosphate to a part of the field had a marked effect
on growth,
TENNESSEE PLANT DISEASE SURVEY, 1943
Hath. Hyre
Following is a summary of surveys made in August, September, and October.
Dr. G. Ds Sherbakoff gave much assistance in diagnosing and verifying
specimens,
Western Tennessee suffered a severe drought this summer. Dodder (Cuscuta
Spe was observed in many GOUntT es. often to. a considerable extent. . It was
especially common on the annua lespedeza.
VEGETABLE DISEASES
CAPSICUM FRUTESCENS, PEPPER
Two l-acre fields were observed in western Tennessee. Sclerotium
rolfsii, southern blight, caused a 20% loss in one acre in Gibson County.
Sun scald caused 25 to 30% loss in one acre in Shelby County.
CUCUMLS Sa'TIVUS, CUCUMBEH
Colletotrichuin lagenarium, anthracnose, was generally present in the
only field observed in Madison County.
IPOMOEFA BATATAS, SWEETPOTATO.
In addition to surveying sweetpotatoes in the field the records of the
state inspectors on sweetpotatoes entered for certification were obtained
. from Professor G. lM. Bentley, State Entomologist and Plant Pathologist,
to whom the writer is indebted.
- *CITRULLUS VULGARIS , WATERMELCN. Only one field of any size was observed»
Colletotrichum 1a enarium, anthracnose caused loss estimated by the grower
at 654 loss (OI, CO.) in one field of Stone Mountain. Fusariuin oxysporum f.
niveum, wilt, is known to be important locally throughout” the State,
Pie aa
> ra
Pe oe
SS ae ay
’ were condemned.: In central Tennessee 6% of 40 acres of Porto Ricos and
Focay cen oxysporum fv: battabie (F. edits and F. hyperoxysporum i
stem rot. In 6 fields surveyed in the large sweetpotato area of western
Tennessee the amount of stem rot varied from a trace to 50% in the Nancy —
Hall variety. The Porto Rico variety usually contained considerably |
less. Mr. Hazlewood, Superintendent of the Western Tennessee Agricultural ©
Experiment Station, stated that stem rot will cause 20 to 25% loss year a
‘in and year out in western Tennessee. Considerably less was found in ll
fields examined in central and eastern Tennessee. ech
In the certification program 0.1% stem rot disqualifies. Because of
stem rot sweetpotatoes of the Nancy Hall variety were not entered for
certification in Gibson, Henry, and Weakley Counties in western Tennessee, —
Of 86 acres of Porto Ricos in 29 fields entered for certification 63%
26% of 137 acres of Nancy Halls in 63 fields were condemned. In eastern ©
Tennessee none of 6 acres of Porto Ricos and 21% of 71 acres of Nancy
Halls in 40 fields were condemned. |
Heterodera marioni, root knot, in the form of 1 or 2 mm. holes on the
surface with disfiguration extending into the roots, is becoming more
important in eastern Tennessee and is seen on many of the roots marketed.
By peeling, after cooking, and weighing. 47 pounds of sweetpotatoes, with
and ti thout nematode injury, a loss of 11% was ascribed to nematode in-
jury with 35 to 100 nematode scars per 1/2-pound root. ;
Endoconidiophora (Ceratostomella) fimbriata, black rot. In the first
field inspection of 71 acres, mostly Nancy Halls, in eastern Tennessee 14
plants with black..rot were found. A trace of black rot on a few early
harvested sweetpotatoes was found in western Tennessee. A large grower
there stated that black rot was no longer a problem with the conmercial
growers in that area.
Mosaic (virus). Only a trace (65 plants in 71 acres) of mosaic was
found in eastern Tennessee.
\
LYCOPERSICCN ESCULENTUM, TOMATO Bar
Twenty-eight fields were surveyed in 19 counties pore ene all parte see
of the State. |
Alternaria solani, early blight, in eastern Tennessee was very general
and resulted in up to 50% defoliation of the plants by mid-harvest season. —
It was progressively less prevalent toward central Tennessee, and in- =
western Tennessee it was virtually non-existent because of the drought. =e
Bacillus sp., soft rot, was umversally present late in the harvest sea-
son but the loss was light. 4
Fusarium oxysporum f. lycopersici, wilt, was found in one county (David-
son) in central Tennessee and in 2 counties in western Tennessee. In
Davidson County 43% wilt occurred in 8 acres in one field and 15% in 3 4
acres in another ficld. In these 2 fields alone the estimated loss to Ree
the farmers was ~500. Ina 3-acre field planted to tomatoes at least 2. .
years in succession, using the same untreated seed bed, 100% wilt was Ԥ
present. In western Tennessee wilt was associated with poor cultural practices.
Heterodera marioni, rootknot, was observed in 3 counties in castern os
Tennessee. A 4-acre field in Sevier County was a total loss Sse 9500+)
chiefly due to rootknot. ;
‘abe: ti tthe d a Na ease Ness anes
251
- Phytophthora infestans, late blight of the foliage and fruit was found
once, on a small patch of tomatoes at Pressmen's Home, Tennessee. The
diagnosis was verified by Dr. C. D. Sherbakoff.
Phytophthora parasitica, buckeye rot, was serious in Jefferson County
and was found in Knox and Warren Counties. In Jefferson County a cannery
estimated 85% loss of the fruit on 500 acres ($55,000).
Mosaic (virus), Insignificant losses could be attributed to mosaic.
In the dry scuthwestern part of the state red spider nearly destroyed
many small patches of tomatoes. It was not a problem elsewhere in the
State,
Sun scald was serious in only a few fields visited. :
PHASEOLUS VULGARIS, BEAN vi
The important bean area of Tennessee is in Johnson and Carter Counties.
Nine fields (204 acres) of the main crop and 3 fields (25 acres) of the
late crop were surveyed. Only small plots (except 10 acres near Nash-
ville) were seen cutside these counties.
Colietotrichum lindemuthianum, anthracnose, was severe in local areas
in Jchnson and Carter Counties. Fifty-three acres seen were abandoned
because of it, 18 acres had 10 to 45% loss, and 100 acres were anthrac-
nose-free. This was in the main crop. It was dry for the late crop and
anthracnose was no problem. |
Pellicularia filamentosa (Corticium vagum), pod rot, affected from 20
to 35% of the pods in 3 of 6 Victory gardens examined.
Fusarium solani f. phaseoli (F, martii phaseoli), dry root rot, was
responsible for 40% loss in 2 fields totaling 22 acres, one at Nashville
and one in Johnson County.
Heterodera marioni, rootknot, resulted in 50% loss in a Knox honors
Victory garden and apparently was the cause of 100% loss of § acres in
Sevier County.
Isariopsis griseola, angular leaf spot, was frequently found in Johnson
County” but was of little economic importance,
Xanthomonas phaseoli, bacterial blight, affected most of the plants in
a i-acre field in Union County.
RHEUM RHAPCrTiCUM, RHUBARB.
Two small fields were observed. In Sevier County a l-acre plot was
marketed the first year because of Phytophthora sp., crown rot. Crown
rot destroved the second plot observed.
SOLANU:i TUBERCSUM, POTATO.
Only about 10 acres of potatoes in ‘the. field were observed.
Phytophthora infestans, late blight, verified by Dr. C. D. Sherbakoff,
was present over a 3-acre field at Pressmen's Home with 50% defoliation
in the worst-affected: areas, The potatoes were just beginning to bloom.
- The farm superintendent said it was the second time he had scen late
blight there in some 25 years. According to the State Inspector no late
blight was present on the Cumberland Plateau this year.
Dr. ‘G. Steiner identified meadow nematode (Pratylenchus pz Pagan as
the -eause of considerable loss to 5 acres of Chippewas on the Cwnoerland _
Plateau,
-
252 : ee | “aca
A trace of spindle tuber (virus) in Sequoias was seen at a grader at
Crossville. ai,
CEREAL DISEASES aay
SORGHUI VULGARE, SORGHUM. About 6 sorghum patches of 1 or 2 acres
each were observed. Colletotrichum lineola, anthracnose, was severe at
Pressments Home. A purple leaf spot was abundant at Pressmen's Home
and was present in Union County in eastern Tennessee, and in Robertson
County in central Tennessee.
ZEA MAYS, MATZE, INDIAN CORN. Thirty- Five fieids of corn were surveyed,
19 in eastern Tennessee and 8 each in central and western Tennessee.
Bacterium stewartii, leaf blight phase, was found in all parts of
Tennessee; from a few percent to 60% or more of the leaves were affected.
Cercospora sorghi, leaf spot. A slight amount was found in upper east
Tennessee.
Cercospora zeae-maydis, leaf spot, identified by Dr. Charles Chupp, was 7
found in 6 eastern and one central Tennessee Counties in a severe form |
in some of them. It was the dominant leaf spot in some areas. It had
not been known to occur in the State previously.
Diplodia zeae, dry rot, was found in measurable amounts only at the
Experiment Station at Knoxville where it varied from about 1 to 8.5% oP
the ears affected in 7 open-pollinated varieties.
Fusarium moniliforme, ear rot, was of no economic ees and was
found following cornear worm injury. ;
:
;
Helminthosporium spp., were abundant in castern Tennessee ed to-a less
extent in central Tennessee. They were virtually absent in western Tennes-
see. At Crossville, H. turcicum was the dominant species; it was also
found quite generally in eastern Tennessee. At Knoxville 3 different
species or races were found. j
Puccinia sorghi, rust, was found only occasionally.
Ustilago maydis (U. zeae), smut, was found in about 25% of the fields,
especially in eastern Tenet varying from 1 to 6% of the cars affect- ;
ed.
“Potassium deficiency was severe in sae ae Tennessce extending
toward the western end of the State,
FRUIT DISEASES
AMYGDALUS PERSICA, PEACH
Five orchards were observed. The crop generally was frozen out this
yeare
Xanthomonas pruni, bacterial spot. A trace was found in a western
Tennessee (ea! ley County) orchard; it was of general occurrence ina
middle Tennessee (Davidson County) orchard; arid destroyed an cstimated
7% of the foliage in an estern Tennessee (Bradley County) orchard.
Monilinia fructicola, brown rot. In one Bradley County orchard the
grower estimated a 30% loss (50 bushels valued at $175.) in a 2% crop.
Dead trees. About 13% of the trees ina large orchard in Roane County —
were dead or dying. The cause is unknown, but is probably borers.
Ree Pert rer eu Shy w 253.
2
Je
7 ea ee
- [ee ot
_ MALUS SYLVESTRIS, APPLE.
Seventeen orchards were visited representing the eastern, central, and
western parts of the State. In addition, considerable inforimation was
obtained from iir. A. N. Pratt, State Horticulturist. A serious killing
frost during bloom greatly reduced yields and led to inadequate spraying
of the remaining fruit.
Glocodes nomigena, sooty blotch, occurring in eastern and central
Tennessee indicated the omission or slighting of early sprays.
Glomerella cingulata, bitter rot, was found in 6 orchards in castern
and central Tennessee. It resulted in serious losses in 2 orchards.
Gymnosporargium clavipes, quince rust, diagnosed by Dr. Paul Ihller, was
found in castern, central, and western Tennessee, usually in small amounts,
but causing concern and resulting in as much as 10 to 15% loss on some
varieties in a few orchards.
Gymnosporangium juniperi-virginianae, cedar rust, was found in an oc-
casional orchard and was severe on the foliage of a large orchard in
Johnson County.
Leptothyrium pomi, fly speck, generally accompanied sooty blotch but
was of little cconomic importance.
Phyllostica solitaria, blotch, was found in only 2 orchards where the
spraying was scriously neglected.
Physalospora obtusa, black rot, was universally present and was, per-
haps, the most serious apple disease this year. Black rot of the fruit
frequently followed codling moth injuries which were all too nuacrous,
and frog-eye of the leaves was often serious.
Venturia inaecvalis, scab, was found in the eastern part of the State
and was a problem only when spraying was neglected. It was virtually
absent in the dry western part of the State.
External cork, verified by Dr. W. D. Mills of Cornell University, was
found in central Tennessee in varying but not great amounts.
DISEASES OF SPECIAL CROPS
\ ARACHIS HYPOGAEA, PEANUT. ‘A number of fields were observed in western
Tennessee. By tne end of August the foliage was quite discasc-free be-
cause of the drought. Sclerotium rolfsii, southern blight was of minor
importance, 2% infection was found in one Madison County ficld, and a
trace in another. .
CANNABIS SATIVA, HEMP. In all but one of a number of fields observed,
generally from the car, no diseases were noted. Sclerotium rolfsii,
southern blight, was not observed except at the Experiment Station at
Knoxville where about 10% of the plants in about one acre were affected
late in July and the disease was spreading.
GOSSYPIUi HIRSUTUM, UPLAND CCTTON. | .
Cotton was not closely observed. Fusarium oxysporum f. vasinfectum, wilt,
in one 4- or 5-acre field in Madison County, destroyed nearly all the
plants in a few spots. Due to potassium deficiency "red rust" was very
general and quite severe in western Tennessee. 7
NICOTIANA TABACUM, TOBACCC. Very little time was given to tobacco and
only a few isolated observations are given here.
25k
Severe infection with Cercospora nicotianae, frog-eye, was observed in
aereg in Favry County with the lower 3 to 5 leaves dead and perhaps a
20% less. Specimens of Conopholis americana, squaw-root were sent to
Dr. Sherbakoff from Gilés County. The parasite was general over the
field. The los; is unknown, Pseudomonas tabaci, wildfire, was severe in
a 2-acre field i: Green County and the farmer was cutting the tobacco
green to save it. ee
One to 2% mosaic (virus) was noted in several fields in Cocke and Green
Counties. Loss was negligible. An acre planting in Sevier County had 7%
ringspot (virus) infection. |
DISEASES OF SOYBEANS AND PEANUTS
Ay
IN THE CAROLINAS IN 1943
R. E.- Atkinson i i“
SOYBEAN. This report covers only the diseases found in the latter part
of the growing season. Most of the fields were visited in September and
Cctober. At that time the early varieties were ripe and had shed their
leaves.
Soybeans are grown principally in the Coastal Plains section of North
and South Carclina. In 1942 in this eastern section of North Carolina
242,000 acres of soybeans were planted. In South Carolina cowpeas are
much more popular as a hay crop and soybeans are grown to a limited extent.
In the course of the survey varietal test plots at the Pee Dee Hxperi-
ment Station, Mdisto Experiment Station, and the Coker Seed Company test
farms st Hartsville were visited in South Carolina. In North Carolina the
Piedmont and the Willard Experiment Station varietal tests were observed.
In addition, 126 fields of soybeans were inspected in North Carolina,
totaling aporoximately 2520 acres. In South Carolina only 45 fields were
inspected, totaling approximately 1,440 acres.
The severe drouth conditions along the eastern seaboard extended through
North and South Carolina. It affected soybeans disastrously and yields of
beans, never as high as in midwestern States, were at unprecedented lows.
Many fields planted for seed were cut for hay.
Bacterial Pustule. The severe defoliation commonly observed was always
accompanied by severe spotting of leaves by Aanthomonas phaseoli var.
sojense, but was usually attributed to the drouth. Bacterial pustule was
by far the most prevalent and most severe disease on soybeans in both
States, It was present in all areas of the two States except for a few
fields in the Piedmont region of South Carolina, where the Ctootan variety
L This report was compiled by the author with the cooperation of Dr. S. G.
Lehman, Plant Pathologist, N. C. State College, and Dr. George iM. Arm-
Strong, Head, Botany and Bacteriology Department, Clemson College:S.(.;
and the section on peanuts with the cooperation of Dr. Luther Shaw, .
Chairman of Plant Pathology, North Carolina State College, Releigh, N. Geum
259
is still generally grown. The most popular varieties in South Carolina
are the Vclstate and the Arksoy, the latter being more severely infected
than other varieties. In North Carolina fields of Mammoth Yellow, Tokyo,
and Biloxi were commonly seen heavily infected with this bacterium.
In test plots the bacterial spot was notably severe on Seminole, Vol-
state, Tokyo, Bilexi and White Biloxi, Mammoth Yellow, Arksoy, Rose Non
Pop, Charlee and Edsoy. It was less severe on Ogden and Clemson Non
Shattering.
Bacterial Blight. It was difficult to differentiate with certainty
between Racterial pustule and Bacterial blight in the field. Perhaps in
one of 10 fields a few spots would be found that were apparently caused
by Pseudomonas glycinea. Nothing was observed in North and South Carolina
in 1943 that would confirm the impression that bacterial blight is usually
evident in every fieid and probably the most conspicuous and common dis-
ease of the soybean; at least that did not hold true in this region in
1943.
Mosaic. iiosaic was especially common on Seminole, Avoyelles, Biloxi
and Yelredo in test plots. It was quite apparent that there are many dif-
ferent types of symptoms produced on the same variety that may be due to
different viruses. In many instances leaf hopper injury rendered the ~
mosaic symptoms difficult to see except on young leaves. The varietal
expression of symptoms produced by both viruses and bacteria needs further
study.
Mosaic was an important problem only in several fields of the Seminole
variety grown near iicBee, South Carolina. This grower had contracted
with the government to grow 350 acres of Seminole, (an edible variety
especially suited to the tropical conditions) which was to be used for
planting. The drouth had reduced expected yields to around 5 bu. per
acre. ieaf hoppers were abundant and the fields had been damaged by the
feeding of this insect.
In his contracted fields 10% of the plants had mosaic, only 1% causing
a severe stunting and rendering the plants practically sterile. This
severe form is probably due to seed=borne or seedling infection.
In a field of 3 acres planted with selected seed fully 80% of the plants
had mosaic. In the central part of the field half of the pvlants had the
severe type of symptoms. This central area bordered on a field of corn
with cowpeas planted between: the rows. The cowpeas were uniformly in-
fected with mosaic. According to the grower there was an abundance of
leaf hoppers in this field also.
The presence of mosaic in these contracted fields would apnoear to limit
the seed to use for human consumption. To use the seed for planting would
be decidedly unwise.
Frogeye. Frogeye (C ercospora sojina) was found in trace amounts in all
the test plots, but in 2 areas it was severe and causing damage In
southeastern North Carolina several fields of Biloxi and one field of
Otootan were severely damaged by defoliation. Lesions on these varieties
were observed on the leaves, stems, and pods. On Biloxi 25% and on Ctootan
LO% of the. remaining leaf surface was affected.
In southwestern South Carolina on Otootan and another See c eam
variety the leaf spot was 100% prevalent but damage was less extensive.
In test fields Gercospora was observed on Edsoy, badens. Steck. okootan,
Laredo, Cherlee, ‘and Missoy. Palmetto was very resistant or iemune. _ The
disease was more prevalent in late plantings.
nthracnose. This disease was found in all test’ plots on the Rocusun .
variety, which had from 25 to 100% of the pods blasted by the fungus Glo-
merella givcines. Varieties growing in adjacent rows were not infected.
At the Piedmont Station the fungus was also found on Ralsoy. At Monetta
and Florence in South Carolina this disease was reported on Georgia 723.
Downy ‘ildew. Peronospora manshurica was found in trace amounts in
all areas of the 2 States, although it was not important exceot as a pos-
sible source of seed infestation. Downy mildew was most severe in north-
eastern North Carolina where in late fields of Mammoth Yellow-and ‘ood's aa
Yellow the disease was 100% prevalent. Some plants were so thoroughly in- ©
fected that the disease appeared to be systemic. No infection was found
on the pods and the area was not again visited so the condition of the seed
is not known.
Southern Blight. This disease was found throughout the 2 States. The
response to the disease varie1 greatly. In a field of Arksoy 20% of the
plants were killed by Sclerotium rolfsii. in another field of 30 acres /.
10% of the plants were “killed and close by in a fiela of the same variety
only 3% of the plants were kil2ed. In a field of Biloxi 10% ofthe plants
were killed just as they reached maturity.
In southvestern South Carolina the lesser corn borer heavily damaged
Tields of peanuts, cowpeas, and soybeans. Although S. rolfsii is not
ordinarily thought of as a weak cr secondary parasite, many plents almost
girdied by the borer were attacked by S. rolfsii. It would be interesting
to know tne degree of interaction bétween the insect and the fungus. In
one ficld the yicld was reduced at least 20% by the fungus and the insect.
At “'iindsor, North Carolina 2 severe outbreak of southern blight in the pe
test plots enabled the tentative classification of the varieties on the
basis of their reaction to the disease. In several replications, Palmetto,
Manioxi, Seminole, Biloxi, White Biloxi, and Yelredo were rated very sus-
ceptible, Mammoth Yellow, Macoupin, and Arksoy, susceptible, and Mamotan
6640, Clemson Non Shattering, and Wood's Yellow as resistant. In a nearby
field of Arksoy there was 15% reduction in stand by S. rolfsii while a
field of “jood's Yellow had less than 1% of the plants affected. - mon
Miscellaneous Diseases. Charcoai rot caused by Sclerotium bataticola
was found in trace amounts in many fields. In all test plots the variety
Boone was ‘100% infected. Cther early varieties were revortcd infected.
_Macroophomina phaseoli was collected on Seminole on stems 2 to 3 fect above
the ground. The pycnidia and spores were identified by Dr. S. G. Lehman. 3
Fusarium wilt (Fusarium sp.) was especially severe in test plots on
Yelredo, “i1t was also collected, and Fusarium isolated in South Carolina ~
by Dr. Armstrong. Rootknot (Heterodera marioni) was found in many fields,
but the damage caused was difficult to estimate.
Nematospora sp., the cause of yeast spot of soybean, was Hepepbee from-
many localities by Dr. S. G. Lehman (PDR 27:22):602. Nov. 1, 1943). : ae
Pod and stem blight (Diaporthe sojae) and brown spot (Septoria glycines) ~
were not scen this year. a
t here
ou
Fibs Solan ph Sitti (aS Oe et com f
‘ ‘Unidentified Diseases. A circular brownish spot, not quite so reddish
brown and less angular than that caused by Septoria glycines, was found
on Nanda, “Wood's Yellow, Brunette, Tokyo, Wannamaker, Delsta, and Seminole
at the Pee Dee Station. The first 3 varieties were heavily infected. At
the Coker Sced Company plots 26 miles away the disease was not seen. In
northeastern North Carolina some fields had only a trace, others were
plastered with the spot. In one field severe spotting was associated with
complete defoliation. In microscopic examination of leaves from different
. fields spores of Helminthosporium were found in considerable numbers.
Tsolations have thus far failed to yield cultures of Helminthosporium, the
most common fungus isolated being Alternaria tenuis.
At the Picdmont Experiment Station a white stem spot was found on
Clemson Non Shattering, Volstate, Tennessee Non Pop, Wood's Yellow, and
Mammoth Yellow.- No fungus could be found fruiting on or near these spots,
and there was no evidence of insect punctures or eggs present. The color
of the soot was due to the dead bleached epidermis which was tautly stretch-
ed over a sunken canker-like cavity. The white epidermis was often split
or cracked. isolations from these spots have failed to yicld any certain
fungi consistently.
PEANUTS. Peanuts are grown in 3 areas of the Carolinas. In the oldest
area, in northeastern North Carolina where peanuts are grown most inten-
Sively,-over 200,000 acres were planted in i942. The oldest pveanut-growing
area in South Carolina extends along the state line across from Augusta,
Georgia, toward Charleston, South Carlonia. In this area, 36,000 acres of
peanuts were planted last year. The newest is a more or less continuous
area in the 2 States, and coincides with the border bright leaf tobacco
belt. In the new area over 20,COO acres were as to peanuts in South
Carolina and 30,000 in North Carolina.
The estimated loss from peanut leafspot has varied in past years from 1
to 2% in South Carolina to 20 to 30% in North Carolina, Virginia, and
Georgia. The reason for this discrepancy was one of the purposes of the
peanut disease survey. Another object was to ascertain if the leafspot
was severe cnough in the new areas to make a blanket recommendation that
all growers dust peanuts.
Leafspot. The leafspot caused by Cercospora spp. is universally present.
It was found in every field examined and undoubtedly oceurs before harvest
in all plantings. The prevalence, however, varied from a trace to 100%,
and the severity from 0 to 50%. In some fields only a tuft of heavily
spotted leaves remained on the stems at harvest time. In general, the dis-
ease was less scvere this season than for many years. The decreased sever-
ity was probably due to the severe drought of late summer and carly fall
which also decreased yields in all areas.
Leafspot is closely associated with maturity and does not become severe
until about two weeks before harvest. Thus, in fields side b» side the
- same variety will vary greatly in the amount of leafspot, devending on
the date of planting. This was particularly conspicuous in a ficlid in
which adjacent rows were planted at different times by the same planter,
and with the same seed. The rows planted early had severe leafspot with
25% defoliation. The part of the field planted later had only a scatter-
ing of spots on the lower leaves and no defoliation.
“ - — = a oo) , ef se
258 Beara
There was less leafsoot in the new than in the older areas, in general, —
but many fields in the new area had leafspot as severe as in the older ;
areas. The low infection in the newer area may have been due to the poor
stands, wnich were very common in the fields in this area. The poor
stands have been attributed, after a careful survey by VY. ©. Nettles, Ex-
tension Entomelogist at Clemson, to clogging or some other mechanical
failure of the planter. Poor stands are rare in the old peanut-growing
area in North Carolina.
The average defoliation was 50% in the old peanut-growing areas of North
and South Carolina, respectively, and 30% in the new area. This probably
means that the loss was from 10 to 20% in the old areas and from 5 to 10%
in the new area,
It would seem therefore, that if a farmer has a good stand, dusting for
the control of leafspot should be recommended in all areas.
scuthern Blignt. Dead plants or branches killed by Sclerotium rolfsii
varied from 0 to 10%. It seemed to be as common in the new area as in the
Older areas. No relation between the previous crop and the prevalence of
the fungus was observed. Perhaps if the prevalence of susceptible weed
hosts in the previous crop were known, a relaticnship might be established.
A plant may be completely killed by S. rolfsii but more often only a few
dead branches mark the attack of the fungus. Dead and partially dead .
plants have been found to total as high as 10% of the plants. Many affec-
ted plants were apparently vigorous and healthy, the only sign of disease
being the loose strands of the fungus growing among the fallen leaves at
the crown of the plant. That these plants are severely damaged cannot be
doubted for often when they are pulled and shaken only a few nuts remain -
attached. The pegs (gynophores) were rotted through by the fungus at soil :
level. Some of the nuts left in the soil were sound and undamaged; usual- - —
ly about half of them were rotted. Plants adjacent in the row to plants
killed by S. rolfsii may or may not be affected.
Nut Rot. Another and apparently unrelated source of great loss to the
farmer is the rot of peanuts in the soil. This has not been adequately
surveyed but on plants dug at random in fields sometimes half of the nuts
on a plant were rotted. There are apparently many insects that damage
nuts in the soil but most of the rotted nuts were free from any obvious
insect injury. This nut rot was not associated particularly with injury
to tops by Sclerotium rolfsii but the possibility that this fungus by
damaging the pegs, predisposes the nuts to rot should be investigated.
Shortly after these peanut rots were reported (September 16) rotted pea-
nuts were cultured. Mcst rotted mits yielded the :common molds -as': Penicillium,
Trichoderma, and Rhizopus. The fact that these organisms are non-varasitic
stressed the possibility stated above, that damage to the pegs by S. roif-
sii might predispose the nuts to rot.
About the :iddle cf Gctober when peanut harvest was in progress the <a
writer returned to Raleigh, North Carclina. By this time alarmed reports
were coming in from'farmers in the old peanut area who were finding a high
percentage of rotten peanuts. The expected 2/3 of a crop had dwindled in
many cases so greatly that fields were not worth stacking and picking. Al-
though great reductions in yield were undoubtedly due to a poor growing
season which prevented setting of nuts except at the crown of the plant,
a reduction of at least 50% in several counties was due to the rotting of
y
‘
q
4
ct
_ Was general in many fields examined and was severe in 3 fields. About
le, on the average for the fields examined, of the plants were killed by
7
Page fare eo
Seas .
ean 3
sis 259
nuts in the ground and to the severence of the peg by S. rolfsii causing
the nuts to drop off the vine. The nut rot was not severe in the old
peanut growing area of South Carolina. The condition of the nuts after
picking was not observed in the new area.
Miscellaneous Diseases. Bacterial wilt (Pseudomonas solanacearum) was
revorted from:Northampton-County and nematode injury (Heterodera marioni)
was found in a field of the Virginia Bunch variety in Bertie County, North
Carolina.
Leaf hopper "burn" was followed by various fungi, mostly species of
Alternaria, which caused the tips of the injured leaflets to turn black
and die.
SUMMARY CF PLANT DISEASE SURVEYS IN GEORGIA, 1943
G. M. Stone
VEGETABLE CROPS
ABELMOSCHUS ESCULENTUS, OKRA. A high percentage of the plants were
wilted by Fusarium wilt (F. oxysporum f. vasinfectum) in a field in the
Augusta area, and the disease was also found in gardens in this area,.in
north Georgia, and the Griffin area. Rootknot (Heterodera marioni) was
prevalent in practically all gardens examined. .
BRASSICA OLERACHA var. BOTRYTIS, CAULIFLOWER. Bacterial leaf spot
(Pseudomonas maculicola) was general throughout 16 acres on the crop just
beginning to head near Darien, but caused little damage. Nearly 100% in-
fection by black rot (Xanthomonas campestris), with about 15% of the plants
dead at the time of observation, occurred in 16 acres at Woodbine.
BRASSICA OLERACEA var. CAPITATA, CABBAGE. Most fields examined in the
mountain section of north Georgia had been cut over at least one time.
In these fields the remaining plants were usually severely infected by
black leaf spot (Alternaria circinans). Worm damage was heavy and an un-
determined soft rot followed the worm injury in many heads.
CAPSICUM FRUTESCENS, PIMENTO PEPPER. The following diseases were ob-
served in the commercial area at Griffin. Only a few pods were found af-
fected by anthracnose (Glomerella cingulata). Bacterial spot (Xanthomonas
vesicatoria) was found in all fields examined, infection varying from
general but light infections in some fields to severe infections in others.
Plants in a few fields had been heavily defoliated. Little damage to the
fruit resulted. A limited amount of blossom-end rot (physiogenic) was
found, but more occurred than of anthracnose or ripe rot. Cercospora leaf
spot (C. cavsici) was general in all fields examined and causing heavy de-
foliation with killing back of the tender branches in several fields.
Mosaic (virus) was general in all fields examined; usually a high percent-
age of the plants were infected. Ripe rot (Vermicularia capsici), which
is most cestructive in wet seasons, was found this year in only one
‘crop delivered to the canner in Griffin. Rootknot (Heterodera marioni)
southern blight (Scelerotium rolfsii).
it was estimated that at least 25% of the entire Georgia cron was lost
due to disease. |
IPOMOBA BAT.:TAS SWEETPCTATO. Black rot (Endeconidiophora (Ceratostomella)
fimbriata) was general; an occasional crop with heavy losses was observed.
Leaf spot (Phvilost: losticta batatas) was general but infection was light with
no apparent « caniage. ~ Stem rot (Fusarium oxysporum f. batatas) occurred
generally over the State, but no more than 1% of the plants were affected
except in an occasional field.
LYCCPERSICCH ESCULENTUM, TCOMATOC.. Several small fields (1/2 to 1 acre)
in north Gecrgia were observed to be severely damaged by early blight
(Alternaria solani). The leaves and tender branches were killed and a
high percentace or of the fruit was rotted. Blossom-end rot (physiogenic)
was also prevalent and rootknot (Heterodera marioni) was moderately severe
in the sume fields. Ina 3-acre field in Augusta, scuthern blight (Sclero-
tium rolfsii) was the principal cause of the loss of 50 to 60% of the
stand, while 1C to 15% of the remaining plants were wilted by Fusarium
wilt (. oxysperum f. lycopersici).
PHASEOLUS VULGARIS, BUNCH BEANS. The late crop was examined in the
mountain section of north Georgia. Anthracnose (Colletotrichum linde-
muthianum) caused severe damage in 2 fields planted with seed of ‘unknown
origin. Bacterial blight (Fant hononas phaseoli) cccurred in scattered in-
fections on stems and oods in one field. Mosaic (virus) was general in
most fields. In several fields as many as 35% of the vlants were diseased.
Powdery mildew (Erysiphe yolygoni) was general in all fields; in scme all
above-ground parts were affected and damage was severe. Scattered infec-
tion, of Rnizoctonia stem and pod rot (R. solani) was observed on stems
and pods in one field. Rootknot (Heterodera marioni) was found in many
creek-bottom fields. It was causing severe damage in 2 fieids. Rust
(Uromyces ohaseoli var. typica ) (U. appendiculatus) was found in all fields
examined. Severe infections occurred in many fields, with the pods "rust-
Same
DISEASES CF SPECIAL CROPS
ARACHIS HYPOGAEA, PEANUT. Cerccspora leaf spot (C. personata and ¢. 2
arachidicola; no effort was made to distinguish between the 2 species) |
was found generally over the entire State. It was decidedly more severe
in the old neanut-growing area in south Georgia. Defoliation was heavy
in many fields of Spanish peanuts; apparently it was less severe on the
runner types. Damage in the old belt amounted to at least 10%.
Phyllosticta leaf spot (apparently P. phaseolina) was reported by Naomi
C. YJoodruff of the Georgia Experiment Station. It was found scattered in
several fields where it caused little damage.
Southern blight (Sclerotium rolfsii) was almost as widespread as the
Cercospora leaf spot. it caused greatest damage in the old belt where a
high percentage of the plants were infected. Losses were extremely
heavy in some sections, especially where harvest was delayed. Damage was
greater than itias reported earlier.
veer RT
, GOSSYPIUi SPs COTTON. Angular leaf spot (Xanthomonas malvacearum)
was general in all fields but, infection was light. Anthracnose (Glome-
rella gossypii) occurred on scattered bolls in several fields. In one
field from 5 to 10% of the plants. -were wilted by Fusarium wilt (F. oxy~
sporum f, vasinfectum); 2 fields. were observed with severely wilted
"spots". Scattered bolls in several fields examined were affected by |
Fusarium boll rot (Fusarium spp.).‘ Severe infestation by rootinot (Hetero-
dera marioni) was observed in a field in the Griffin area.
_ SACCHARUM CFFICINARUM, SUGAR CANE. Red rot (Colletotrichum falcatum)
is reported to have been prevalent in banks in 1943, but losses were moder-
ate. Mosaic (virus) was general on susceptible varieties. Losses were
heavy in many patches.
NICCTIANA TABACUM, TOBACCO. Except for a few isolated cases of fairly
high percentages, not more than 1% of the plants were infected by bacter-
ial wilt (Pseudomonas solanacearum). Downy mildew (Peronospora tabacina)
was epidemic in Georgia in the spring of 1943. About 80% of the plants
in beds were killed. However, sufficient plants survived to set the crop.
(From oral report by J. G. Gaines, Coastal Plain Experiment Station,
Tifton).
MISCELLANEOUS HOSTS
CARYA ILLINOENSIS, PECAN. Early infections by scab (Cladosporium ef-
fusum) were heavy on susceptible unsprayed varieties over the entire south-
eastern belt pecan area. Losses for the entire season on unsprayed /sus-
ceptible trees ranged from 25 to 75%. Brown leaf spot (Cercospora effusa)
and downy spot (Mycosphaerella caryigena). were prevalent under the same
conditions as scab. Rosette (zine deficiency) was of minor importance in
1943 (Information furnished by John R. Cole, Pecan Field Laboratory,
Albany).
VIGNA SiiZNSIS, COWPEA. Bacterial leaf spot (Pseudomonas syringae)
(Bacterium vignae) was found scattered in several fields. Cercospora leaf
spot (C. cruenta) was general in all fields examined but caused little
damage. Five to 10% of the vlants in one field were wilted by Fusarium
wilt (F. oxysvorum f. tracheiphilum) (F. vasinfectum var. tracheiphilum).
Leaf spot (Anerosporium oeconomicum) was found in all fields examined but
was very scattered in distribution and apparently caused no damage.
Powdery mildew (Erysiphe polygoni) caused general and severe damage in
many fields where plants were defoliated and tender branches killed back.
ZEA MAYS, CORN. Ear rot (Fusarium moniliforme) was severe on several
varieties in the University variety test at Athens, and was prevalent in
fields examined in south Georgia. Smut (Ustilago maydis) (U. zeae) was
found scattered in all fields examined. :
SULIARY CF OBSERVATIONS ON PLANT DISEASES IN FLORIDA
DURING THE EMERGENCY PLANT DISEASE PREVENTION PROJECT SURVEYS ~
JULY 25 TO DECHBER 31, 1943.
Arthur Se Rhoads
VEGETABLE CROPS
Weather conditions during late September and the first half of October
were generally unfavorable for farm operations in the truck crop sections
of Florida. Heavy rainfall greatly delayed operations, with extensive
losses to seedbeds and early plantings in some sections. Later in the
season leck of soil moisture retarded crop production in some sections
without subirrigation. General shortage and high cost of labor, particu-
larly of experienced workers, proved to be a great handicap to growers and
in many cases portions cf crops had to be sacrificed where there was little
likelihood of their proving profitable with the excessive labor cost. Dam-
age from cold weather caused extensive losses to many of the more tender
crops in different sections of north central and central Florida.
BRASSICA CLERACEA var. BOTRYTIS, CAULIFLOWER. Xanthomonas campestris,
black rot, was found to be serious in one 5-acre planting at Sanford, where
the disease adparently had been attacking plants since they were fairly 4
young and was causing wilting and dying of plants large enough to begin
forming heads. The plant loss was estimated to be 3C% and the disease
appeared to be spreading rapidly.
BRASSICA OLSRACEA var. CAPITATA, CABBAGH. Peronospora perasitica, downy
mildew, was found to be of widespread occurrence in practically all the
cabbage-growing areas visited in north central and central Florida, fre-
quently resulting in heavy loss of plants in the seedbeds where growers
were not in position to dust or spray at frequent intervals or failed to
do a timely or thorough job. Evidence of this disease was noted on the .
older leaves of heading piants in a number of iocalities but in no case .
did it appear to cause any appreciable injury to the crop. .
Rhizoctonia root rot was observed to cause losses in parts of new plant-
ings at a few places but they were mostly small and local in extent. A
more serious case of this troubie was observed in a much older 5-acre
planting at “inter Garden, where the plant loss was estimated at 5h.
Cne grower at Zellwood, who had 50 acres of cabbage seedbed sown in
drills, reported that this planting was lost by cold weather, the tempera-
tures going dowm to 25, 26, 27 and 36° F. on 4 consecutive mornings. This
was an especially serious loss as he claimed to have had sale contracts
for 2 million slants and the cold kilied them about a week before they
would have becn ready for marketing. 4
CAPSICU:: FRUTESCENS, PEPPERS. Plantings of peppers were greatly retarded 4
by excessively wet soil conditions and some acreage at ‘Jinter Varden and %
Minorville was killed, while in other cases the plants recovered but tended
to remain abnormally small. ,
Cercospora. candsici, leaf spot, was of widespread occurrence in one of the 7
few fields seen at Sanford, where it caused considerable defoliation. In |
the ‘inter Garden area, however, where the new blight-resistant ‘/jordbeater
varicty vas grown exclusively, the amount of leaf spot was negligible.
Her aged bey Ten eS PO eee! Se ae eee a 4
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263
Rhizoctonia solani apparently was responsible for occasional dying of
plants in one l6é-acre field at Winter Garden. Miscellaneous fruit rots
occurred in most fields visited, especially where fruit rested on the
ground, but losses from this cause were relatively small and partly aided
by worms.
Pepper plantings examined in the northern part of the State were remark-
ably free from diseases and particularly mosaic, which was later observed
to occur very extensively in some plantings in the vicinity of Dania on
the lower East Coast.
CICHORIUM EMDIVIA var., ESCAROLE. Alternaria-cichorii, leaf spot, was
observed in one.lecal area in one large field being cut at Sanford,
necessitating heavy trimming to eliminate the unsightly-appearing outer
leaves. This disease also was noted occurring quite generally in a 2-acre
planting at Minorville. It is rarely troublesome during the cooler por-
tion of the year and during that season fields are planted solidly, with
no space left to permit driving through with spray machines.
CUCUMLS SATIVUS, CUCUMBERS. Pseudoperonospora cubensis, downy mildew,
was the only disease that proved to be troublesome in plantings in the
Wauchula section and those found at a few other points. The mildew was
being held under control fairly well by dusting but in some cases the
dusting did not appear to have been done with particular thoroughness of
coverage so far as the lower sides of the leaves were concerned. One
planting of 1 1/2-acres was so severely attacked by mildew as to probably
reduce the yield by 50%, especially as picking had not yet begun. Cold
winds caused considerable leaf injury in two 10-acre plantings at Clear-
water and Jinter Garden, respectively. Rootknot (Heterodera oe was
rather prevalent in one 1C-acre planting at Winter Garden. |
_CUCURBITA PEPO var. CONDENSA, SQUASH. Little in the way of diseases
was observed in scattered plants of squash in Alachua and Marion Counties,
most of which were small. Pseudoperonospora cubensis, downy mildew, was
observed in some plantings but had not become sufficiently sevcre to re-
sult in any particuler crop curtailment. A trace of blossom blight (Choane-
phora cucurbitarum) was observed in a few plantings and cucumber mosaic
(virus) was noted on a few fruits in one planting. The plantings in these
2 northern counties were all killed prematurely by early frost.
DAUCUS CAROTA, CARROTS. Poor stands in young plantings on muck soil at
Zellwood were attributed partly to dryness and coarseness of the surface
.S0il in portions of the fields and to cold injury while the plants were
‘still very young. No diseases were observed in any of the plantings ex-
amined, 3
IPOMOEA BATATA, SWEETPOTATO. Plantings of sweetpotatoes examined at
various points in north central and western Florida appeared quite free
from diseases so far as the vines were concerned. The only diseases ob-
__served were white rust (Albugo ipomodeae-panduranae) and leaf blight (Phyl-
‘-losticta batatas) and neither were sufficiently severe to be of any
particular consequence,
LYCOPERSICON ESCULENTUM, TOMATOES. Alternarie solani, early blight, was
_. found to- have caused considerable infection of leaves of plants in one
- local area of an unusually fine 30-acre planting on prairie land west of -
_ Rockledge, which was nearly ready for picking. However, this disease was
26h
kept urder control by spraying and a very profitable crop made. The suc-
cess oi this Dianting was jeeperdized by heavy rainfali earlier in the
season but an additional pump was secured and installed in time to save.
all but ebout an acre in a depressed area that could not be drained so ef-
fectively,.
PHASECLUS VULGARIS, SNAP BEANS. Only a few small plantings were observed
and these mostly efter most of the crop had been picked. Nost of these
showed areas where the plants were more or less yellowed am occasionally
somewhat stunted from infestation by jassids.
PISU:: SATZVUH, PEAS. Rhizoctonia root rot apparently was responsible
for dying and loss of from 35 to- 40% cf the plants in a 1 1/2-acre planting
at Wauchula. Cther small plantings suffered losses of varying extent from
cold.
SCLANUM MELOi GENA, EGGPLANTS. Phomonsis vexans, blight and tip-over,
was the most serious disease found on this crop, presenting a serious pro-
blem for growers in Alachua and Merion Counties southward to central
Florida, it commonly attacks plants in all stages from recent transplants
to those approaching maturity. The principal injury resulted from the
basal girdling of the plants, though lesions resulting in less serious
injury conmoniy developed at other points on the stems. Rotting of the
fruit was more or less common in most fields and other losses were report-
ed in transit. Nc appreciable leaf spotting was apparent. Plant losses
usually ranged from 10 to 25% in most fields examined and in a few cases
ran up as high as 75%.
Pseudomonas (Bacterium) solanacearum, bacterial wilt, was observed to
have taxen a heavy toll of plants in one 1C-acre field at Martin, where
Phomopsis blight also was particularly widespread and many plants were un-
usually severely infected by rootknot (Heterodera marioni). This vlanting
was said to have been a total loss.
Heterodera marioni, rcotknot, wes found infecting plants in a few
fields but the one just mentioned was the only one in which they were
especially severe. ,
Early frost kilied all the fall eggplant plantings in Alachua and Marion
Counties before their full productiveness was over.
CEREALS, GRASSES, AND FORAGE CROPS
CASSIA TORA, COFFEEWEED. Erysiphe polygoni, powdery mildew, was of
widespreed occurrence on plants at Ccala end Belleview. Rhizoctonia solani
apparently was responsible for the wilting and dying of patches of seed-
lings in a cover crop pilot at Quincy where coffeeweed was grown in rotation
witn tobacco, Héterodcra marioni, rootknot, was found infecting reots of
old plants severely in another cover crop plot.
CRCTALARTA. Oidium erysiphoides var. crotalariae, powdery mildew, oc-
curred abundantly on - on plants of C. retusa at Lake Alfred. Erysinhe poly
powdery mildew, was widespread on leaves of C. spectabilis, showy Crot9a-
laria, at liclrose, Devil's Millhopper near Gainesville, and Minorville.
CYMCDON DACTYLON, BERMUDA GRASS. An undescribded species of Helmintho-
sporium was associated with an extensive browning and dying of leaves in
a test plot at the North Florida Experiment Station at Quincy.
265
DESMCDIUii TORTUCSUM, BEGGARWEED. Oidium sp., apparently the conidial
stage of Microsphaerea diffusa, caused extensive mildewing of plants grow-
ing as a cover crop in a citrus grove at DeLand and as an escape at Gaines-
ville. No perithecia developed, however, even by the time the leaves were
._ killed by cold.
LUPINUS CUMULICOLA. Cercospora longispora was observed causing large,
conspicuous sooty spots on the leaves, with considerable defoliation, at
De Soto City.
ORYZA SATIVA, RICE (upland). A Helminthosporium-like eye-spot was of
general occurrence in a field examined at Perry. What appeared to be the
same disease was of widespread occurrence on spreading witch-grass or fall
Panicum (P. cichotomiflorum) that was growing abundantly adjoining the-rice
field and occurring scattered throughout it. Unfortunately, the fungus
was not fruiting on material collected on either host.
PANTCUH. An unidentified species of Ovularia was found causing dark
linear streaks on leaves of plants of P. haemitomum, maidencane, between
Largo and Semincle. (See also under rice).
PASPALUM URVILLEI, VASEY GRASS.. Puccinia levis, rust, was collected on
this grass at Island Grove and Yanford.
PENNISETUM PURPUREUM, NAPIER GRASS. Helminthosporium ocellum, cye-spot,
was of very general occurrence on susceptible varieties at the Experiment
Station but occurred sparingly or not at all in test plots of selections
for resistance to this disease.
PUERARIA THUNBERGIANA, KUDZU. Pseudomonas medicaginis var. phaseolicola,
bacterial leaf spot, was prevalent in plantings at Quincy but the snots
were small and the disease not sufficiently severe to result in much de-
foliation.
SOJA MAX, SOYBEANS. Frog-eye disease (Cercospora sojina) (C. daizu) and
bacterial pustule (Xanthomonas phaseoli var. sojense) were responsible for
defoliation in variety test plots of the Experiment Station at both Gaines-
ville and Quincy. Anthracnose (Colletotrichum glycines) commonly attacked
the pods in both these localities. The prevalence of this disease, however,
was not so important as it might seem since the pods usually failed to de-
velop any appreciable amount of seed anyway.
The consistent failure to secure seed production appears to constitute
the greatest drawback to soybean culture in Florida. The pods commonly
fail to fill out properly and shrivel and shed prematurely. This trouble
was apparent at Gainesville, Quincy and at other points in western Florida.
SORGHUM HALUPENSE, JOHNSQN GRASS. Cercospora sorghi, leaf spot, attacked
plants severely at Quincy. Colletotrichum lineola, anthracnose, also oc-
curred to a slight extent on the same plants. Puccinia purpuree, rust,
was prevelent on plants in the same locality.
SORGHUM VULGARE, SCRGHUM. Ascochyta sorghi was found occurring sporadi-
cally on plantings of the Texas Seeded Ribbon variety at both Quincy and
near Perry. Leaf spot (Cercospora sorghi) was found to be of frequent oc-
currence in some plantings, resulting in considerable premature dying of
leaves. Anthracnose (Colletotrichum lineola) was of common and widespread
occurrence in some plantings, also causing considerable premature dying of
the leaves, Zonate spot (Glococercosnora sorghi) was of f&irly common oc-
currence in plantings of the Texas Seeded Ribbon variety at_both Quincy
and near Perry, causing extensive blotching and dying of. Tegos Rust
(Puccinia sorghi) was found in but one of several plantings exainined in
western Florida, infection being noted on 25% of the plants in a portion a
of a field that still remained unstripped. Head molds due to Fusarium
and other saprophytic fungi that commonly attack the inflorescences during Be
the warm, humid rainy season of late summer resulted in greatly curtailed
seed formation in some varieties in test plots of the Experiment Station
at Gainesville.
STIZOLOBLUIi DEFRINGIANUM, VELVET BEANS. Leaf spot (Vercospora stizo-
lobiae) was of widespread occurrence and an important factor in defoliation |
in all plantings examined, but the velvet bean caterpillar Sen Ae
gemmatilis) was by far the greatest factor in defoliation.
Potash deficiency appears to have become a limiting factor in making
crops of velvet beans of late years in sections of western Florida where
fertilizer is not used. Test plots of the North Florida Experiment Sta-
tion at Monticello showed a marked response of plants to applications of
dolomitic limestone, potash, and phosphoric acid. Potash deficiency ap-
pears to be the main limiting factor, however. Plants with no fertilizer
consistently made a very weak growth, with scanty seed production. The
leaves of such plants became distinctly chlorotic and the margins fired
and died, and the plants became defoliated early.
VIGNA SINENSIS, CCWPEAS. Leaf spots due to Amerosporium oeconomicum and
Cercospora dolichi resulted in considerable defoliation in plantings at
Quincy. Rhizoctonia root rot apparently was the cause of. wilting and dy-
ing of seedlings in a cover crop plot at Quincy, where cowpeas were rota-
ted with tobacco, Rootknot (Heterodera marioni) also was observed as a
cause of unthriftiness of plants in another field at Quincy.
ZHA MAYS, CCRN (field). Puccinia sorghi, rust, caused widespread and
heavy leaf infection in the case of late plantings observed at Quincy and
Jay. This disease is said to attack late plantings in western Florida
rather severely as a rule.
FRUIT AND NUT CROPS
ALEURITES FORDIT, TUNGOIL. Clitocybe tabescens. Clitocybe root rot,
was observed to be of widespread cccurrence and highly destructive to
trees in commercial plantings at a number of points in northern Florida,
being associated especially with situations where oak trees were prevalent
prior to clearing. Ina 100-acre block near LaCrosse 69 trees were found
in various stages of decline from this disease, 41 of these occurring | in
one local area, and numerous others had been removed previously. |
Pellicularia koleroga (Vorticium stevensii) thread blight, was of wide-
spread occurrence and proved troublesome to trees on 130 acres of a large
‘planting at Lamont. The disease was confined chiefly to the lower-lying
land, especially where the trees were closely planted. In the lowest por
tion adjacent to the hammock forest virtually all the trees exhibited more
or less of the disease, The company spent nearly $8CO in pruning 30 acres
of trees in an attempt to control the disease, but with little evidence
of success. Spraying, however, has proved very effective. ‘Trees sprayed |
once in 1942 and again during the summer of 1943 appeared fairly free from
the disease.
2
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:
slp koi ul aaa Sa 267
ee AMYGDALUS PERSICA, PEACH. Uercosporella persicae, frosty mildew, was
found attacking the leaves of 2 trees.at Melrose. -
CARYA ILLINOENSIS, PECAN. Cercosporella. caryigena. (Mycosphaerella caryi-
gena), downy spot, was found occasionally on trees at Monticello. ‘Clado-
sporium effusun, scab, was of widespread occurrence on various varieties
at Monticello and other points, Causing a heavy dropping of nuts‘in some
cases. Elsinoé randii, nursery blight, was observed occurring commonly
in one nursery at Monticello, causing extensive defoliation and a ragged,
unsightly appearance of seedlings. Microsphaera alni, powdery mildew, was
found occasionally on nuts in 2 orchards at Monticello. Pestalotia uvicola
Was associated with large, irregular dead areas on leaves of trees in one
orchard at Monticello. Phoradendron flavescens, mistletoe, was observed
occurring with great frequency at most localities throughout Florida where
pecans have been planted, ranging from Dunedin on the lower ‘Jest Coast to
- Cocoa on the middle Bast Coast and northward to Monticello and DeLand. It
frequently grows in great profusion on.old, neglected trees.
CITRUS. Citrus groves in Volusia, Lake, Orange, Brevard, Polk, Highlands
and Pinellas Counties appeared to be in finer condition in general than
ever before. This is due to the widespread use of dolomitic limestone and
other soil amendments and nutritional sprays that has become the general
practice during the last few years. As a result of this modern program
of fertilization, groves are now characterized by much less gunmosis and
less dead wood from bronzing, frenching, exanthema (dieback) and other dis-
eases now conceded to result from deficiencies or lack of availability of
certain essential nutritional elements. The reduction of these widespread
causes that formerly contributed so greatly to the production of dead wood
has in turn brought about a great reduction in the prevalence and Se
of melanose.
Melanose (Diaporthe citri) was reported to be worse than usual this year
in the vicinity of DeLand, cwing to the cold in February, and also in Polk
and Pinellas Counties, owing to rainy weather following blooming. Scab
(Elsinoé fawcetti) did not appear to be particularly troublesome in any of
the sections visited. These diseases, which were formerly regarded as
serious factors in reducing fruit grade and marketability, are now consi-
dered relatively unimportant from an economic standpoint owing to the use
of such a large proportion of the fruit for canning. Melanose is still
an important factor’ in citrus fruit production, however, from the stand-
point. of the Phomopsis type of stem-end rot.
Botryodiplodia diplocarna was found to be of general occurrence on dying
branches of Tahiti lime trees in a rather neglected grove between Lotus
and Tropic on Merritt Island. It causes.a bluish-black discoloration of
the wood similar to that caused by Diplodia natalensis (Physalospora rho-
dina), but appears to be essentially secondary on branches weakened or
dying from various causes.
Stylar-end rot of Tahiti limes, considered to be a physiological break-
down of maturing fruit, also occurred to some extent on the imore mature
. fruit on a number of trees in the same grove.
Clitocybe tabescens, Clitocybe root rot, was observed to have developed
fo yon 3 additional grapefruit trees on rough lemon stock in a grove at Waverly
_ where this disease has been prevalent for a number of years. Ustulina vul-
20
garis was found fruiting at the base of two. trees and Ganoderma appla-
natum var, tornatum on the other. These 2 fungi have been observed by
the writer in: former years in this particular grove, occurring as sccond-
ary fungi on trees attacked by Clitocybe root rot.
Phytophthora parasitica, foot rot, continues to cause decline and death
of trees, cspecially in those sections where sweet seedling orange trees
are grown, |
Decline of trees on rough lemon stock was observed to be prevalent
throughout the ridge section from Lake Alfred south to Lake Placid and
also in Pinellas County on the West Coast. This trouble has been occurring
for many yeers but the cause has not been determined. It usually occurs
sporadically on trees in certain groves and appears to develop most fre-
guently in situations where they are periodically subject to drought. Tree
losses are causing some growers considerable concern.
Saline irrigation water proved extremely injurious in a number of groves
in the Indian Rocks, Seminola and Annona sections of Pinellas County, re-
sulting in extensive defoliation and dying back of large bearing trees.
The water table has been materially lowered over a period of years by ex-
cessive drainage and by subnormal rainfall over a period of years. Groves
suffered so severely from drought during the past year that it was neces-
sary to irrigate over a period of 9 out cf 11 months. After irrigating
for some time it was found that the water pumped from artesian wells had
become quite saline in some instances. Analyses of the water showed a wide
variation in salt content and in one or two instances showed about 4800
p.p.m. of NeCl. Samples taken from various wells showed that the salt con-
tent often increased greatly after but from 2 to 3 hours of pumping.
Cuscuta americana, dodder, was found forming an extensive imat cnveloping
—the tops of 2 large bearing orenge trees-Ina grove inthe Eloise scction near
Winter Haven.
Vines that overrun trees and cause injury in citrus groves arc reported
in PDR 27:692-693. |
MALUS SYLVESTRIS, APPLE. Pestalotia sp. was found associated with a
leaf spot on a single small tree 5 miles north of Milton. The spots were
smali and the disease appeared to resuit in no appreciable damage,
MORUS WIGRA, BLACK MULBERRY. Cercosporella mori, leaf spot, was collec- ~—
ted at Juincy, Greenville, and Gainesville, sometimes being sufficiently
severe to cause extensive defoliation. a
PSIDIU:! GUAJAVA, COMMON GUAVA. Colletotrichum gloecosporioides (Glome- 1
rella cingula nia), ripe rot, was of frequent occurrence at Tropic, territt,
and later at Homestead, the disease apparently gaining entrance at times
througn insect punctures.
VITIS HMUNSOCVIAVA, BIRD GRAPE. Phyllosticta viticola, the conidial stage
of Guignardia bidwellii, leaf spot, was of frequent and widespread occur-
rence throughout central and southern Florida, occurring with great pro-
fusion on Key Largo. q
VITIS ROTUMDIFCLIA, MUSCADINE GRAPE, Phyllosticta viticola, leaf spot, “|
occurred abundantly on wild vines at Quincy. Septoria ampclina, leaf spot, —
also occurred abundantly in the same locality. A large leaf-blotch caused —
by an as ycot undetermined Sphaeronema-like fungus was collected on wild
Vines between Bristol and Telcgia.
=
”
269
VITIS RUFOTOMENTCSA, REDSHANK GRAPE. Plasmopara viticola, downy mildew,
occurred abundantly on vines in one locality between Newman's Lake and
Orange Heights. An unusual fungus with grayish spore masses borne in
rounded heads on stalks, apparently a species of Diplococcum, also occurred
on other leaves of the same vines, causing a distinctive, irregularly zo-
nate type of spot. |
VITIS VULPTIA, FROST. GRAPE. Isariopsis clavispora, leaf blotch, was of
infrequent occurrence between Micanopy and iicIntosh.
SPECIAL CROPS
ARACHIS iYPCGAEA, PEANUTS. Cercospora leaf spot wes of general occur-
rence in all of the many fields examined from Marion ard Alachua Counties
in north-central Florida to Escambia County at the extreme western end of
the State. This disease usually resulted in defoliation ranging from 25 -
35%, and in one case 50%, in undusted fields. The small, short-spored
spot (Cercospora personata) was the predominant one found in matcrial ex-
amined from Marion, Alachua, Jackson, Jefferson, Santa Rosa, Okaloosa and
Escambia Counties. The large, long-spored leaf spot (Cercospora arachidi-
cola) was noted only in plantings at Aucilla, Quincy, and near Crestview.
Good control of this disease was secured by dusting in tests conducted by
the North Florida Experiment Station at Aucilla and Allentown. In.the
former locality sulfur dust was found to have given about 18% increase
over undusted plots and copper-sulfur dust about 2-3% higher increase in
yield of nuts on the Florida Runner variety.
Decay of nuts was reported in one field near Allentown. The nuts exam-
ined showed evidence of Rhizoctonia, and Diplodia natalensis was observed
fruiting on lesions on stems of the same plants.
GOSSYPIUM spp., COTTON. Diplodia natalensis (Physalospora rhodina) was
of more or less general occurrence as a cause of boll rot in many of the
cotton fields visited late in the season in Jackson, Holmes, Santa Rosa
and Escambia Counties. | ws
Diplodia natalensis and Sclerotium bataticola (Macrophomina phaseoli) were
both associated with a widespread dying of mature plants in one field at
Madison, where plants were said to have been dying gradually since the
seedling stage, resulting in about 25% loss, The latter fungus was asso-
ciated with a similar dying of mature plants in a field 10 miles east of
Tallahassee,
HIBISCUS SABDARIFFA, RCSELLE. Heterodera marioni, rootknot, was found
infecting roots of a test planting of this crop with extreme severity, on
nematode-infested land at the North Florida Experiment Station.
RICIiUS COMMUNIS, CASTOR BEAN. Botrytis cinerea, gray mold, occurred
abundantly in a »vlot-planting at Gainesville, attacking the inflorescences
in various stages of development. This disease, which has been of frequent
occurrence in parts of Florida for a considerable number of years, spreads
— rapidly during the warm, humid rainy summers and constitutes a serious
_ hindrance to seed production.
SACCHARUM, SUGARCANE. The numerous plantings examined in north and west
Florida appeared to be remarkably free from diseases, though in some cases
adversely affected by dry weather. Plantings of this crop in the northern
See Anan POR oem eGR oo Ny kA:
Maree ee ih enn i BNL ONIN ave?
. - j as
270.
part of the State are now limited largely to 3 disease-resistant varieties.
Eye-spot (Helminthosporium ocellum) occurred to some extent in one plant-
ing near Perry but did not constitute any appreciable factor of loss. Mo-
saic (virus) was noted only in small patches of one of the old-time var-
jieties at Quincy and Cak Grove. In both cases adjacent plantings of re-
Sistant varieties were free from this disease.
TREES, ORNAMENTALS, AND MISCELLANEOUS HOSTS
Observations already summarized on occurrence of Clitocybe root rot,
mistletoe, dodder, wood-rotting fungi, entomogenous fungi, lightning stroke,
etc., on wocdy plants, are not repeated here. (See PDR 27 (19): 486, Cct.
Ts (20): 556, Oct. 152522) 2632, Now. 1s, (23): 636-697, Now to. ee
694-696, 697, Dec. 1, 1943; and PDR 28 (7): 260-272, Apr. 1, 1944).
ACER CARCLINIANUM. Rhytisma acerinum, tar spot, was observed at Suwanee
Springs and at Suwanee Gables east of Old Tom...
AESCULUS PAVIA, RED BUCKEYE. The Phyllosticta stage of Guignardia aes aes-
culi was found causing leaf blotch and defoliation of a single LESS s
-Torreya State Park.
. ARECASTRU.! ROLIANZOFFIANUM, PLUMY CCCONUT. Ganoderma zonatum (G. sulca-
tum) was observed fruiting at the bases of dying trees at Cocoa and Clear-
water, Curly-top (menganese deficiency) was noted in young palms at Se-
bring, Dunedin, and various points along the East Coast.
ASTiMINA OBCVATA, BIGFLCWER PAWPAW. Cercospora asiminae, leaf spot, was
found on plants at DeScto City.
BACCHARIS HALIMIFCLIA, EASTERN BACCHARIS. .Dimeriella melioides, Had milcéw
was found on leaves of plants at Juniper Springs, Umatilla, near Meritt
Island, and between Jensen and Stuart.
BIGHONTA CAPRECLATA, CRCSSVINE. Caponodium elongatum, sooty mold, was
collected in Sanchez Hammock 10 miles northwest of Gainesville. Meliola
bidentata, black mildew, was found occurring fairly commonly at Gaines-
ville and points in the vicinity. ;
POFRHAAVIA ERECTA, ERECT SPIDERLING. ibugo platensis, white rust, was
of conmunon occurrence on this plant growing as a weed in a pecan grove at
Monticello,
BROUSSCNETIA PAPYRIFERA, PAPER MULBERRY. Cerccspora broussonetiae, leaf
spot, was observed at Quincy..
CALLICARPA Ai HRICANA, AMERICAN BEAUTYBERRY. Cercospora oe
leaf blotch, was collected at Melrose.
CALONYCTIC!: ACULEATUM, MCONVINE. Albugo troueeace sana a a white
rust, was collected at Boren ce |
CATALPA BIGMCKIOIDES, SCUTHERN CATALPA. Cercospora catalpae was observ~\. —
ed to be causing extensive spotting and defoliation of roadside trees near |
the entrance to Torreya State Park.
mD.iUS DisCD.RA, DECDAR CEDAR. Clitocybe tabescens, Clitocybe root rot,
was found to have practically killed an ornamental tree planted in a
residential property at Quincy. The disease stimulated a profuse exuda-
tion of resin from the base of the trunk, and upon dissection of the trunk
it was found that extensive zones of pathologic resin canals had developed
ee eT eo eee td ee Dag ee AS is O8S Aan : ;
allt re aS a ae Ay ? ,
Tein Clee : 291
{
Pe oot rings formed after the disease had attacked the tree, some
. of the canals being continuous from the base to the tip of the tree, which
_ was about 13 féet high. The wood of Cedrus normally is characterized by
the complete lack of resin canals. Pure cultures of the fungus were se-
-eured in isolations made from the roots.
CHAENOMELES JAPONICA, JAPANESE FLOWERING QUINCE. Cercospora cydoniae,
leaf spot, was of common occurrence on a few ornamental bushes at both
Monticello and Quincy, resulting in almost complete defoliation in all
cases,
CORNUS spp., DCGWOOD. Cercospora cornicola, leaf spot, was causing ex-
tensive defoliation of ornamental trees of flowering dogwood, C. florida,
at Gainesville and Quincy. Meliola nidulans, black mildew, was fairly com-
mon at times on plants of small-fruited dogwood, C. microcarna, about
Gainesville and Silver Springs. The fungus develops profusely on twigs and
even good-sized stems.
CRATARGUS spp., HAWTHORN. Entomosporium maculatum, the conidial stage
of Fabraea maculata, leaf blight, was observed to be causing considerable
defoliation of trees of Ravenel hawthorn, ©. ravenelii, in Sugarfoot Ham-
mock west of Gainesville. Phyllactinia corylea, brown mildew, was found
with good development of perithedia, on oneflower hawthorn, C,. uniflora,
in Sugarfoot Hammock.
CUSCUTA spp., DODDER. C. americana was found on orange trees (PDR 27:
692). C. compacta was found occurring abundantly on a number of native
shrubs in the vicinity of lakes and bayheads at Gainesville, eo ya
Evinston, and lionticello (See PDR 27:556, 696-697; 28: 269). ©
ELAEAGNUS sp. Cercospora elaeagni, leaf spot, occurred abundantly on
a group of these shrubs planted at Oakland. Colletotrichum sp. also oc-
_ curred in association with these spots.
-ELEPHANTOPUS spp. Coleosporium elephantopodis, rust, was collected at
Gainesville on stems and leaves of E..carolinianus. The uredinia were
parasitized by Ramularia coleosporii. The rust. occurred sparingly on plants
of E. tomentosus in Torreya State Park.
EMILIA SOMNCHIFOLIA. Puccinia. /€miliae, rust, was abundant on plants at
Cocoa. . ;
, ERYTHRINA HERBACEA, EASTERN CORALBEAN. An apparently new species of
Cercospora was found occurring abundantly on leaves of plants in scrub
woods at De Soto City, the infected leaves having the appearance of having
been attacked by a rust. This is the first record at Gainesville of the
occurrence of a Cercospora on this host in Florida.
EUPATORIUi! CAPILLIFCLIUM, DCGFENNEL. Cuscuta compacta, dodder, was
found occurring abundantly on stems of this tall weed at Evinston and
Gainesville,
FRAXINUS CAROLINIA, CAROLINA ASH. Cylindrosporium fraxini, leaf spot,
was found occurring abundantly at Newnan's Lake near Gainesville. This
appears to be the first record of this disease for Florida and also on a
new host for the fungus. The collection was made jointly with lir. Erdman
West.
GORDONIA LASIANTHUS, LOBLOLLYBAY GORDONIA. Meliola cryptocarpa, black
_Mmildew, was collected at Altoona,
299
GREVILLEA ROBUSTA, SILK OAK. Gummosis was observed on the trunk of a
large ornamental tree at Leesburg. The cause of this trouble was not ap-
parent but it has been attributed to Diplodia natalensis (Physalospora
rhodina) in other instances. In the butt of a recently felled companion
tree showing no particular evidence of gummosis, short zones of pathologic
gum canals were found in the interior wood, marking a point where gum
formation had occurred previously.
HAMAMELIS VIRGINIANA, WITCH HAZEL. Gonatobotryum maculicola, leaf spot,
was found in Torreya State Park, this being the first record of this unique
fungus in Florida. Records of it heretofore have been confined to a few
northeastern States.
HYDROCOTYLE sp., PENNYWORT. Puccinia hydrocotyles, rust, occurred
abundantly on this plant on low wet wet ground along the Indian River at Cocoa.
HYPTIS MUTABILIS, WCOD SAGE. Puccinia hyptidis-mutabilis, rust was found
to occur commonly in the vicinity of Gainesville. It was collected at
Windsor and Lowell also. :
HYPTIS RADIATA. Puccinia hyptidis, rust, occurred abundantly on plants
between Orange Heights and Melrose. A later collection made unusually
late in the season in the same locality showed that the rust had become
extensively parasitized by Dariuca filum.
ILEX CASSINE, DAHOON. Cercospora . ilicicola, leaf spot, was found oc-
curring sparingly at Melrose. This fungus does not appear to have been
recorded from Florida previously. Capnodium elongatum, sooty mold, oc-
curred abundantly on bushes in the same locality.
Englerulaster orbicularis, black spot, occurred so profusely on leaves
of bushes in the same locality and aiso in Sanchez Hammock near Gainesville
as to greatly reduce the value for Christmas decorations. Although the
fungus was immature it was commonly overrun in both these localities by
silvery gray patches of CE ee but there was no evidence of sporulation
by this apparently parasitic fungus.
Pestalotia annulata, was found causing large leaf spots, mostly terminal,
on plants at Umatilla.
Phacidium curtisii, tar spot, was found occurring but sparingly on plants
at Melrose and oniy a trace of it was seen on plants in Sanchez Hammock,
Silver Springs and other points. The dahoon holly does not appear to be
nearly so susceptible to this disease as the American holly.
ILEX CORITACZA, LARGE GALLBERRY. Englerulaster orbicularis occurred —
abundantly on leaves of plants at Umatilla. Phyllosticta ilicicola, leaf
eters was collected on a few leaves of plants in the same locality.
BX .OPACA,.:. AMERICAN HOBRLY. Capnodium: clongatum . was observed in
Soa Hammock northwest of Gainesville. Engleruiaster orbicularis,
black spot, was found occurring commonly at various points in the vicinity
of Gainesville. Phacidium curtisii, tar spot, was observed to occur com-
monly in the vicinity of Gainesville.
TPOMOBA TRICHOCARPA. Puccinia crassipes, rust, was found fruiting abun-
dantly on leaves of vines at Ocala, occurring in association with Coleo-
sporium ipomoeae.
ITEA VIRGINICA, VIRGINIA SWEETSPIRE. Septobasidium sinuosum, felty
fungus, was collected at Melrose and south of Barberville, the collections
being limited to a single specimen in each case. This is a hitherto un-
reported host record for the occurrence of this fungus.
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idiella rufula was. found occurring “Tene. on dead twigs of
shrubs south of Barberville and at Glencoe, 3 miles west of New Smyrna.
LANTANA SELLOWIANA, TRAILING LANTANA. Puccinia lantanae, rust, was
-_ collected at Gainesville.
LEONOTUS NEPETAEFOLIA, LIONSEAR. Puccinia leonotodis (P. Henn.) Arth.,
II, rust, was collected on this plant growing as a weed in an abandoned
sand pear orchard 7 miles north of Ocala on November 8, 19/43. This col-
lection, the determination of which was verified by Dr. George B. Cummins,
- is the first record of the occurrerce of this rust in the United States,
it being previously known in the West Indies.
LIQUIDAMBAR STYRACIFLUA, SWEETGUM. Conopholis americana, squaw-root,
was found growing from roots of trees in Sanchez Hammock northwest of
Gainesville and at Magnesia Springs. | ‘
LYONIA FERRUGINEA, FETTERBUSH. Hxobasidium vaccini, eae galls, were of
fairly common occurrence on plants at Altoona. Phacidium nigrum, tar-spot,
was observed occurring commonly in the vicinity of Gainesville, near Lynne
- on: the Ocala National Forest, and west of Astor Park.
_LYONIA LIGUSTRINA var. FOLIOSIFLORA, BRACTED HE-HUCKLEBERRY. Puccini-
astrum myrtilli, rust, was observed occurring sparingly at Micanopy.
Rhytisma andromedae-ligustrinae, tar ei was SS on senescent
leaves of the same plants. —
MAGNOLIA VIRGINIANA, SWEETBAY MAGNOLIA. Meliola magndliae, black mildew,
was a common leaf blemish at Melrose. Phyllosticta glauca, leaf spot, was
found to be of extremely common and widespread occurrence,- collections
having been made at a number of points from Crestview and DeLand south to
Royal Palm State Park. Where leaf infections are abundant considerable
defoliation results. |
.Phyllosticta magnoliae, leaf spot, was found causing extensive defolia-
tion at Longwood. This disease is very similar to the. preceding except
that the spots average considerably larger ,and the ears? are larger and
not rod-like as in the preceding.
MELIA AZEDARACH, CHINABERRY. Cercospora el eee ee spot, was
observed occurring abundantly on a tree south of Lotus on Merritt Island
and to be of common occurrence on trees at Gainesville.”
MYRICA CERIFERA, SOUTHERN WAXMYRTLE. Irenina manca, black mildew, was ~~
found occurring fairly abundantly in the vicinity of y of Gainesville, Melrose,
along the Ocklawaha River several milés east of Silver Springs, Barber—
ville, and in Royal Palm State Park. ~~
Galls (cause unknown) were. observed rather eonunnis on stems of bushes
in the vicinity of Gainesville, Melrose and Juniper Springs. In the young-
er galls the bark was intact but in older ones promienent circular to
elongated swellings occurred and the hypertrophied wood tissue was devoid
_of bark on-the older part. This gall formation was observed in former
years on waxmyrtle and also flameleaf sumac (Bhus copallina) on Merritt
Island. | | See CMT eT
NERIUM OLS@ANDER, OLEANDER. Sphaeropsis sp., witches' broom, was observed
on a number of ornamental bushes at Sanford, DeLand, Cocoa, City Point,
Rau Gallie, Miami, and Coconut Grove.’ “This disease is reported to have
become. increasingly widespread and destructive about Miami during the last
few years. It -characteristically appears again in the new growth that
develops after infected plants are cut back severely, thus appearing to
Ok.
be systemic. VWJitches' brooms were found to have deveiocen in the first
growth that put out in 2 of a series of cuttings being propag zated at the
Deering Estate.
NYSSA OGECHE, CGEECHEE TUPELO. An unidentified leaf spot was observed
to be causing extensive defoliation of trees along the road between Chip-
ley and Bonifay and in the river bottom on the Holmes-Washington County
line. No disease has been reported on this tree in Florida vreviously.
Unfortunately, the fungus was not fruiting and could not be identified.
OPUNTIA, PRICKLYPEAR. Perisporium wrightii, black spot, was observed
to occur fairly commonly at Altoona, between DeLand and Orange City, and
at Crlovista. .In previous years the writer has found this disease occur-
ring commonly on various species of Opuntia along the East Coast from
Vero Beach north to near St. Augustine.
OSMANTHUS AMERICANUS, DEVILWCOD OSMANTHUS. Capnodium elongatum, sooty
mold, was found occurring abundantly at Gainesville. Meliola sp., was of
common occurrence at Gotha. The fungus has been considered to be M.
amphitricha Fr, but this vague species was excluded by Stevens in his
monograph of the genus. Phyllosticta sinuosa, leaf spot, was of widespread —
occurrence in western Florida, collections having been made 10 miles —
northwest of Perry and at Torreya State Park. .
PERSEA HULIILIS , SILKBAY PERSEA. Phyllosticta micropuncta, leaf spot,
was observed in scrub woods west of Astor Park.
PHORADEMDRCL FLAVESCENS, MISTLETOE. This parasitic plant was found to
be of widespread and frequent occurrence throughout northern and central
Florida but appears to occur infrequently in western Florida and on the
lower Hast Coast. It extends southward in the State at least to Lake
Placid and Clearwater and was recently found on Key Largo. It occurs most
frequently on various oaks, including laurel, water, turkey, bluejack,
and myrtle oaks, hickory, pecan, swamp black gum tupelo, and black cherry.
It occurs with extreme frequency in areas of oak scrub, Mistletoe has
been recorded as occurring on more than 50 species of trees and shrubs in
the State. Host records have been reported in PDR 27(23):637-638, Nov.
15, 1943, and 28 (7):262-269, Aprii 1, 1944. 2
Sphaeropsis visci, leaf blight, nitherto unreported for Florida, has
been found to be of very common and widespread occurrence. Other fungi
found on mistletoe are Septobasidium pseudopedicellatum, and Tryblidiella
fusca, new host records in both cases (PDR vol. 28, p. 269).
PINUS sop., PINE. Cronartium fusiforme, southern fusiform rust, was
found occurring occasionally on P. caribaea, slash pine, at points about
Alachua County and in various counties in western Florida. It occurs to
some extent in planted slash pine forests in SuwannecCounty. The disease
appears to occur much less frequently on this host than on Pinus taeda
or P. echinata. It was found occurring frequently in various west Florida
counties on P. echinata, shortleaf pine, being especially abundant between
Tallahassee and Quincy and about Quincy. It was of common occurrence on
P. taeda, loblolly pine, in Alachua, Jefferson, Gadsden, Taylor and Dixie
Counties. It frequently attacks young trees with great severity, often
seriously deforming them.
PLEIOBLASTUS CHINO. Puccinia melanocephala, rust, was found occurring -
on this bamboo which had escaped from cultivation and become a veritable
pest. The uredinia were extensively parasitized by Monosporium uredini-
colum Stevens. Meliola tenuis, black mildew, also occurred on other
QTD
eerie in the same locality.
QUAMOCLIT VULGARIS, CYPRESSVINE. Coleosnorium ipomoeae, rust, was
found causing extensive infection on vines between Largo and Seiinole.
PCINSETTIA HETEROPHYLLA. Uromyces proeminens var. poinsettiae, rust,
was of common occurrence on this weed at Tropic, Merritt Island.
POLYCODIUM FLORIDANUM, DEERBERRY. Pucciniastrum myrtilli, rust, was
found causing slight infection cn plants at Cocoa. Rhytisma vaccinii, tar
spot, occurred to some extent on plants at Cocoa and in great profusion
on large numbers of plants in the scrub woods at Altoona.
PRUNUS CARCLINIANA, -CAROLINA LAURELCHERRY. Exudation of gum from the
base of a young street tree was observed at Quincy but no cause was found.
Another adjacent, similarly affected tree that had just been sawed off at
the ground showed more or less concentric series of pathologic resin canals
developed in the wood. | |
QUERCUS spp., OAK. Microsphaera alni, powdery mildew, was found on
leaves of young laurel oaks, .. laurifolia, at Gainesville, Evinston, Oak
Hill, and Titusville. Oidium spe, probably. the conidial stage of Mi. alni,
was found on a young white oak tree, Q. alba, in Torreya State Park, but
perithecia were lacking.
Trabutia erythrospora, tar spot, was.of common’ occurrence on old leaves
of live oak, Q. virginiana, trees at Gainesville, Melrose, and Brooksville.
The funges coes not appear to develop mature spores until some time afters
the leaves have fallen.
Wood-rotting fungi were reported in PDR 28(7):261-262.
Conopholis americana, squaw root, was found growing from roots of laurel
oak trees in Sanchez Hammock 10 miles northwest of Gainesville and at
Magnesia Springs, and from roots of a water oak, Q. nigra, at the latter
place.
Phoradendron flayescens, mistletoe, was observed to be conmon especially
on laurel oak. See PDR ° 1. c., under Phoradendron.
RHUS COPALLINA, FLAMELEAF SUMAC. Cercospora rhuina was found to:be of
widespread occurrence throughout north centrai and central Florida, fre-
quently causing premature shedding of the attacked leaflets.
RCSA PALUSTRIS, SWAMP ROSE. Phragmidium speciosum, rust, was found
“producing telia on a single stem tip in Sugarfoot Hammock west of Gaines-
ville, where it has been observed in former years.. The uredinial stage
was cee overwintering on persistent leaves in another locality at Gaines-
ville,
RUBUS ? ARGUTINUS, BLACKBERRY. Irenina manca, black mildew, was abundant
on plants at Altoona.
SABAL ETONTA, ETCNIA PALMETTO. Myriangium sabaleos Weedon, leaf spot,
was found at De Soto City. This is a new host record for this little
known fungus, which appears to have been known only on cabbage palmetto,
(Sabal palietto), on which it was described from a collection made at St.
Petersburg in 1923. As Miller has pointed out (Mycologia 32:589. 1940),
this does not appear to belong to Myriangium. |
_ SABAL PALETTO, CABBAGE PALMETTC. Ganoderma zonatum (G. sulcatum Murr.),
which occasionally ‘attacks palms, was observed fruiting at the base of a
living tree at Longwood. These species are now regarded as synonymous
by Dr. Murrill, the former having priority.
SERENOA REPENS, SAW PALMETTO. ‘Meliola palmicola, tae ? :
found to be an extremely common and nd widespread disease, it fine Fecal y ob=
served at many points throughout northern and central Florida. Gi
SIDA spp., TEAWEED. Ramularia areola, frosty mildew, was found causing E.
widespread infection of plants of Sida carpinifolia at points about ce
Gainesville and Citra, of S. acuta at ‘Umatilla, and be S. rhombifolia at
Bonaventure, |
SMILAX AURICULATA. Capnedi.um elongatum, sooty ma was found in San-
chez Hammock 10 miles northwest of Gainesville. Cercospora smilacis, leaf
spot, occurred abundantly at De Soto City.
SMILAX LAURIFOLIA, LAUREL GREENBRIER. Cercospora smilacis, leaf spot,
occurred abundantly 10 miles northwest of Perry. Pestalotia funerea was
found associated with a leaf spot at Umatilla.
TILIA FLORIDANA, FLORIDA LINDEN. Conopholis americana, squaw-root, was
found growing from roots of a tree at Magnesia Springs. ,
VACCINIUM ARBOREUM, FARKLEBERRY. Ophiodothella vaccinii was of common
occurrence as a cause of leaf spot at Suwanee Springs, Altoona, and Eustis. —
VERBESINA VIRGINICA, WHITE CROWNBSEARD. Coleosporium viguierae, rust, oc-
curred abundantly on plants near Merritt Island P. O., Merritt Island and ‘
on Hypoiuxo Island. . ;
VERNONIA OVALIFOLIA. Coleosporium vernoniae, rust, caused heey. infec-
tion of plants in Torreya State Park. |
XANTHIUM AMERICANUM, COCKLEBUR. Erysiphe iiohomaeea mio powdery ‘iden |
was found attacking leaves of plants near Milton, Allentown and Cak Grove 4
at the western end of Florida, and also at Ocala. Puccinia xanthii ~
attacked plants severely at Allentown and Oak Grove and less so at Ocala.
PLANT DISEASES OBSERVED IN ALABAMA IN 1943
G. M. Stone’ and J. L. Sead
VEGETALBE CROPS
ABEL:IOSCHUS ESCULENTUM OKRA. Leaf spots caused by Cercospora althaeina
and Phyllosticta hibiscina were found scattered in most plantings, causing
no apparent damage. Rootknot (Heterodera marioni) and Fusarium wilt (F.
oxysporum f. vasinfectum) were of major importance and caused severe dam-
age in a high percentage of gardens especially in the southern part of
the State, iki
BRASSICA CLERACEA var. ACEPHALA, COLLARDS. Rootknot (Heterodera marioni)
was prevalent in the southern part of the State, causing more damage than —
other diseases. Only scattered infections of blackleg (Phoma lingam) and
ringspot (Mycosphaerella brassicicola) were observed. Black rot (Xan-
thomonas campestris) (Bacterium campestre) was more prevalent than blackleg —
but did not occur in*sufficient amount to cause much damage.
BRASSICA OLERACEA var. CAPITATA, CABBAGE. Rootknot (Heterodera marioni)
was of major importance, being prevalent in the southern section and caus—
ing moderate damage in many fields. Black leaf spot (Alternaria circinans) —
’ * “ ee Te Be rs ets i tT pee er bel fr 7? a hte Se tie Ses bl bia nie Lar, orth} 4 is
. Ne A A ok a Nee
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oF 1 Le
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F-a
was of minor importance; it became prevalent late in the season after most
_ of the cabbage had been cut. Black rot (Xanthomonas campestris) and bac-
terial soft rot (Erwinia carotovora) were of greater importance than black
leaf spot; they were destructive in occasional plantings. Only a few in-
fections of black leg (Phoma lingam) and yellows (Fusarium oxysvorun f.
conglutinans) were seen. Southern blight (Scloerotium rolfsii) occurred
in occasional plantings.
BRASSICA RAPA, TURNIP. Rootknot (Heterodera marioni) was the most preva-
lent disease and caused considerable damage to many plantings in the south-
ern part of the State. Scattered infections, with little damage, of black
rot (Xanthomonas campestris), leaf spot (Colletotrichum brassicae), and
mosaic (virus), were observed.
TPOMCEA BATATAS, SWEETPOTATO. Rootknot (Heterodera marioni) was of
major importance in the southern part of the State. Scurf (Monilochaetes
-infuscans) was fairly general. In some crops a high percentage of the
plants were affected, but little damage resulted. Stem rot (Fusarium
oxysporum f. batatas) was generally distributed over the State but less
than 1% of the plants were infected. Leaf spot (Phyllosticta batatas)
was of minor importance; although it was found in most fields, no apparent
damage resulted. Java black rot (Diplodia tubericola) was found occasion-
-ally in the southern part of the. State. Dry rot (Diaporthe batatatis) was
common in storage but losses usually were low.
LYCOPERSICON ESCULENTUM, TOMATO. Diseases of major importance were
Fusarium wilt (F. oxysporum f. lycopersici), which was general and caused
losses that were quite often heavy where susceptible varieties were grown,
especially in home gardens, and early blight (Alternaria solani), southern
blight (Sclerotium rolfsii), and mosaic (virus), all of which- were more
prevaient in 1943 than usual and caused moderate damage.
Bacterial wilt (Pseudomonas solanacearum) was found to cause considerable
- damage in quite a few plantings in the southern part of the State,
Blossom-end rot (physiogenic) was general, being’ found in almost every
planting seen, but losses were not great.
Leaf spot (Septoria lycopersici) was rather prevalert but caused little
damage. : .
Anthracnose (Colletctrichum phomoides), bacterial canker (Corynebacterium
michiganense), bacterial spot (Xanthomonas vesicatoria), gray mold rot
(Botrvtis cinerea), and stem rot (Rhizoctonia soiani), were of slight in-
portance, being found only occasionally.
PHASEOLUS VULGARIS, GREEN BEANS. Rodtknot (Heterodera marioni), a root
rot caused by Diaporthe sp., and southern blight (Sclerotium rolfsii), were
the most important diseases, causing mderate to severe damage in many fields.
Mosaic (virus) was general, and considerably more prevalent in 1943 than
usual. Damage was moderate. |
Powdery mildew (Erysiphe polygoni) and rust (Uromyces phasecli var.
typica } were general, but of no consequence on the early crop. Eoth were
more severe on the late crop.
Bacterial blight (Xanthomonas phascoli) was not very prevalent and
_. . caused moderately low damage.
_ Anthracnose (Colletotrichum lindemuthianum), bacterial wilt (Pseudomonas
~— solanacearum), black root rot (Thielaviopsis basicola), leaf blotch (Cer-
— , €ospora cruenta), and stem rot (Sclerotinia sclerotiorum), were each found
278
in a few plentings, causing slight damage.
SCLANU:: TUPEROSUM, POTATO. Early blight, (Alternaria solani) was more
. destructive than usual and was of major importance on the early crop.
Seattered infections of bectcrial wilt (Pseudomonas selanacearum) and
Fusarium wilt (F. oxysporum) were noted; less than 1% of the dlants were
affected. Scab (Actinomyces scabies) was of minor importance, as was also
soft rot (Bacillus sp.) which was less prevalent than usual. Cnly an oc-
casional plant affected by southern blight (Sclerotium rolfsii) was noted.
CEREALS AND FORAGE CROPS
AVENA SATIVA, CATS. Crown rust (Puccinia coronata) is of major impor-
tance on oats in Alabama. Infections in 1943 were malerate. Loose smut
(Ustilago avenac) was prevalent in fields from untreated sced but losses
were considerably less than those caused by crown rust.
HORDEUM VULGARE, BARLEY. A rcot rot caused by a species of Helmintho-
sporium was of major importance in the "black belt" of Alabama and caused
severe damage to early plantings. Both loose and covered smuts (Ustilago
spp.) are prevalent in the State and rather destructive where -seed t reat-
ments are not practised. Leaf spot (Helminthosporium sativu and powdery
mildew (Erysiphe graminis) were found in most fields but apparently caused
little damage. !
LUPINUS ANGUSTIFCLIUS, BLUE LUPINE. Both Fusarium wilt (F. oxysporum f.
vasinfectum) and southern blight (Sclerotium rolfsii), which are usually
of minor imoortance, were ee eae a more prevalent than usual in 1942
and caused moderate damage.
PISUM SATIVU! var. ARVENSE, AUSTRIAN WINTER PEA. Blight and root rot
caused by Ascochyta sp. is the most important disease of this plant in
Alabama and is often the limiting factor in growing it. In 1943 it was
less severe than usual and caused moderate losses.
Downy mildew (Peronospora pisi) was less prevalent than Ascochyta blight;
however, it was more severe than usual and caused moderate loss.
SOJA MAX, SOYBEAN. The most important diseases are mosaic (virus) which
was more prevalent than usual, and southern blight (Sclerotium rolfsii)
which occurred in the usual amounts; both caused moderate loss.
A number cf diseases usually considered of minor importance were more
prevalent in 1943 than usual and caused moderate damage in some plantings;
these include bacterial leaf spot (Pseudomonas glycinea), downy mildew
(Peronospora manshurica), and pod and stem blight (Diaporthe sojae), and
also frog-cye leaf spot (Cercospora so jina) which caused less injury than
the others.
SCRGHUM VULGARE, SORGHUM. Leaf spot (Ascochyta sp.) was of major impor-
tance and caused severe damage in many fields. Leaf blight (Helmintho- —
sporium turcicum) and bacterial stripe (Pseudomonas andropogoni) occurred
generally to a moderate extent, causing severe damage in an occasional
field. Anthracnose (Colletotrichum lineola) was of minor importance, only
occasional irfections being noted.
TRIFCLIU]: PRATENSE, RED CLOVER. Powderv mildew (Erysiphe oolygoni) was
more prevaicnt than usual, occurring generally and causing moderate damage.
Anthracnose (Colletotrichum trifolii) was less prevalent than usual, only
scattered infections being observed.
f
ae
4 te
219
TRIFCLIUM REPENS, WHITE CLOVER. Rootknot (Heterodera marioni), the most
important disease, caused moderate damage. Leaf spot (Cercospora sp.) was
more prevalent than usual and caused siight to moderate damage. Botrytis
blight (Botrytis sp.), leaf blight (Stagonospora sp.}, and southern blight
(Sclerotium rolfsii), were less prevalent than usual.
TRITICU:H ARSTIVUM, WHEAT. Leaf rust (Puccinia rubigo-vera var. tritici)
is the most destructive wheat disease in Alabama. Infection in 1943 was
general and moderately heavy. Loose smut (Ustilago tritici) was found in
most fields but losses were low. Speckled leaf blotch (Septoria tritici)
was found scattered in most fields with no apparent damage resulting. Only
a slight amount of scab (Gibberella zeae) was seen in 1943.
VICIA spp., VETCH. Blight and root rot caused by Ascochyta sp. is of
major importance on common vetch; however, in 1943 it was less prevalent
than usual and caused only slight to moderate damage.
Red rot (cause unknown), usually of major importance on monantha vetch,
was less severe than usual, with slight to moderate damage.
VIGNA SINENSIS, COWPEA. Rootknot (Heterodera marioni), southern blight
(Sclerotium rolfsii) and Fusarium wilt (F. oxysporum *. tracheiphilun),
were found frequently on susceptible varieties in the southern part of the
State. Powdery mildew (Erysiphe polygoni) was considerably more prevalent
than usual, especially late in the season, and late crops were damaged
materially. Scattered infections, causing little damage, of bacterial
spot (Pseudomonas syringae) and Cercospora spot (C. cruenta), were noted.
ZEA HAYS, CORN. Dry rot (Diplodia zeae) and Fusarium ear rot (F. monili-
forme) were more prevalent then usual. Smut (Ustilago maydis) was found
in most fields but less than 1% of the plants were affected. Infection
by brown spot (Physcderma zeae-maydis) was heavier in 1943 than usual but
damage was considereddight. Leaf blight (Helminthosporium turcicum) oc-
curred in scattered infections causing little damage.
FRUIT CROPS
FRAGARTA, STRAUBERRY. The stem nematode, Ditylenchus dipsaci, and the
rootknot nematode, Heterodera marioni, were of major importance. Apparent-
ly the stem nesteatode caused greater damage.
Scattered infections by angular spot (Dendrophoma obscurans), leaf spot
(Mycosphaerella fragariac), and powdery mildew (Sphaerotheca humuli) oc~
curred in most plantings, apparently spat no damage.
Crown-rot (Pellicularia filamentosa) a eeeaa was observed oc-
casionally,
Of the fruit rots, leak (Rhizopus nigricans), was of major importance
and caused moderate to heavy losses, especially with poor handling. Brown
rot. (Rhizoctonia) and gray mold rot (Botrytis cinerea) were noted in oc-
casional infcctions. ~~
SPECIAL CROPS
‘ARACHIS HYPOGAEA, PEANUT. Bacterial wilt (Pseudomonas solanacearum) oc-
curred in scettered infections in the southern part of the State and was
of only slight importance. ;
280
Govacspons leaf spot (C. pe RS and C. arachidicola) was penerats
over the State, It caused little to no damage in the new peanut-growing
areas of the northern part of the State. Infection was much heavier in
the Old Belt", especially when the crop was grown in the same field for
the second year.. About 10 to 15% loss was caused in the "Old Belt".
Southern blight (Sclerotium rolfsii) was prevalent in the "Old Belt",
A high percentage of the plants were infected in many fields but total
damage is considered not to be so great as from Cercospora.
GOSSYPIUM, COTTCN. Damping-off (seedling diseases) were of major im-
portance although much less abundant this year than usual.
Rootknot (Heterodera marioni) was more prevalent on the sandy soils of
southern sections where it is the most important disease.
Fusarium wilt (F. oxysporum f. vasinfectum) was much more prevalent in
1943 than in 1942 and also more prevalent than in the average year.
Blight (Ascochyta gossypii) was considerably more prevalent in 1943 than
usual but this disease is considered to be of minor importance,
Angular leaf spot (Xanthomonas malvacearum) was observed in general, but
very light infections, Anthracnose (Glomerella gossypii) was found only
occasionally. Sparse infections of leaf spot (Alternaria sp.) were noted,
with no apparent damage.
SACCHARUM, SUGARCANE. Mosaic (virus) was of major importance. A high
percentage of the plants were diseased in susceptible varieties.
Red rot (Colletotrichum falcatum) was of minor importance but caused
heavy losses in occasional banks. .
LIST OF PLANT DISEASES OBSERVED DURING SURVEYS ~
IN MISSTSSIPPI AND LOUISIANA, AUGUST TC NOVEMBER, 1943 _
°
L. H. Person
VEGETABLE CROPS
ABELiMOSCHUS ESCULENTUS, OKRA. Heterodera marioni, rootknot: Miss.
ALLIUM spp. The following diseases occurred in Louisiana:
A. ASCALONICUM,.... SHALLOT. Phoma terrestris, pink root; Sclerotium
eepivorun, mine rot; stuntirg am am yellowing, probable virus. .
A. CEPA, ONION. Peronospora destructor, downy mildew; Stemphylium
ey ni (Macro socorium parasiticum), stalk rot.
A, SATIVUM, GARLIC. Sclerotium cepivorum, white rot.
BRASSICA CLERACEA var. BOTRYTIS, BRCCCOLI. Alternaria circinans (A.
brassicae), leaf spot: La. Xanthomonas campestris, black rot: Laws
B, OLERACEA var. CAPITATA, CABBAGE. Alternaria circinans, leaf spot:
La., iiiss. Peronospora parasitica, downy mildew: La. Sclerotinia
sclerotiorum, watery soft rot: La. Xanthomonas campestris, black |
rot: la.
CAPSICUii FRUTESCENS, PEPPER. Southern wilt was noted in both States;
the other reports are for La. Cercospora capsici, leaf spot;
Colletotrichum nigrum, anthracnose; Fusarium annuum, wilt; Gloeo-
sooriun piperatum, anthracnose; Sclerotium rolfsii, southern wilt;
281
Pseudomonas solanacearum, bacterial wilt; Xanthomonas vesicatoria, bac-
. terial: spot;. mosaic (virus).
CITRULLUS VULGARIS, WATERMELON. Alternaria cucumerina (Macrosporium
cucumerinum), leaf blight: La. Fusarium oxysporum f. niveum, wilt: La.,
Miss.
CUCUMIS SATIVUS, CUCUMBER. eocudoperonoapors cubensis, downy mildew: La.
Pythium sp., cottony leak: La. »
IPOMOEA BATATAS, SWEETPOTATO. Actinomyces lpomoea, soil rot: Lae
Diplodia tubericola, Java black rot: La.
Endoconidiophora (Ceratostomella) fimbriata: La. Fusarium oxy sporum £3
batatas, stem rot and wilt: both States. *Heterodera marioni, rootknot:
Miss. Monilochaetes infuscans, scurf: La. Phyllosticta batatas, leaf
spot: both States. Rhizopus nigricans, soft rot: both States. Sclero-
tium bataticola, charcoal rot: La. S. rolfsii, stem rot inthe plantbed:
La. Septoria oataticola, leaf spot: both States.
LYCOPERSICON HSCULENTUM, TOMATO. Alternaria solani, early blight and
nailhead spot: La. Corynebacterium michiganense, bacterial canker; La.
Fusarium oxysporum f. lycopersici, wiit: La. Heterodera marioni, root-
knot; La. Pseudomonas satanacearum, bacterial wilt: both States.
Sclerotium rolfsii, southern wilt: both States. Mosaic (virus): La.
Blossom-end rot (physiogenic): Miss.
PHASEOLUS LUNATUS, LIMA BEAN. Diaporthe phaseolorum, pod blight, and
Sclerotium rolfsii southern wilt: both in Miss.
P. VULGARIS, BEAN. Macrophomina phaseoli, ashy stem blight: Miss. Pythium
sp., stem one blight: Miss. Rhizoctonia microsclerotia, web blight;
both States. Rhizoctonia solani: La. (stem canker), Miss. (root rot).
sclerotium bataticcla, charcoal stem blight: La. S. rolfsii, southern
wilt: both States. Uromyces phaseoli var. tyvica, rust: both States.
Pseudomonas medicaginis var. phaseolicola, halo blight, and Xanthomonas
haseoli, common bacterial blight: both States. Mosaic (virus): La.
ae leaf and pod), Miss. :
PISUM SATIVUM, PEA. Ascochyta pisi, blight, and Erysiphe polygoni, powdery
mildew: both in La. :
SCLANUM MELONGENA, EGGPLANT. Phomopsis vexans, fruit rot: La. Sclerotium
rolfsii, southern wilt: both States. Pseudomonas solanacearum, bac-
terial wilt: La. ;
S. TUBEROSUM, POTATO.. Actinomyces scabies, scab: La. Alternaria solani,
early blight: La. Phytophthora infestans, late blight: La. Pythium
spe, tuber rot: La. Sclerotium rolfsii: La. (tuber rot), Miss. (south-
ern wilt). Corynebacterium sepedonicum, bacterial ringrot: La. Pseu-
domonas solanacearum, bacterial wilt: La. Virus diseases: mosaic in
Miss., mild and rugose mosaic, leaf roll, spindle tuber in La. Haywire
(undet.): La.
CEREALS, GRASSES, AND FORAGE C RCPS
AXONOPUS COMPRESSUS, CARPET GRASS. Physarum cinereum, slime mold: Miss.
MEDICAGO ARABICA, BURR CLOVER. Colletotrichum destructivum, anthracnose,
and C. trifolii, anthracnose: La. |
M. SATIVA, ALFALFA. Pleospora herbarum, leaf spot, and Uromyces striatus,
Tust: La,
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MELILOTUS INDICA, SOUR CLCVER. Colletotrichum Lee sehr ereoene
and Entvloma meliloti, white smut: La.
ORYZA SATIVA, RICE. The following diseases were observed in La.:
Cercospora oryzae, leaf spot; Entyloma oryzae, leaf smut; Helmintho-
sporium oryzae, brown spot; Hypochnus sasakii, banded sclerobial i: disease;
Leptosphaeri salvinii, stem rot; Piricularia oryzae, blast; Rhizoctonia
oryzae, sheath spot; white tip Rane. y
SOJA MAX, SOYBEAN. Except where indicated, these diseases were noted in
. bath States, ‘Gorcospora sojina (C. daizu), leaf spot: La...
Diaportne sojae, poa and stem blight. Sclerotium bataticola, charcoal
“rot. S. rolfsii, southern wilt. Pseudomonas glycinea, bacterial blight.
Xanthomonas phaseoli var. sojense, bacterial pustule. Mosaic (virus): |
SORGHUM VULGARE, SORGHUM. Except where indicated diseases were observed
in both States. Ascochyta sorghina, leaf spot: Miss. Cercospora sorghi,
. leaf spot. Colletotrichum graminicolum, anthracnose. Gloeocercospora
sorghi, zonate leaf spot. ~ Puccinia purpurea, rust: La. Titaeospora ~
andropogonis, sooty stripe. Pseudomonas andropogoni, bacterial stripe.
TRIFOLIUiit DUBIUM, HOP CLOVER. Erysiphe po polygoni, powdery mildew: La.
T. PRATENSE, RED CLOVER. Powdery mildew: La.
T. REPENS, WHITE CLOVER. Cercospora zebrina, leaf spot; Cymadothea-
trifolii, sooty blotch; and Pseudoplea trifolii, leaf spot: La, }
VICIA FABA, BROAD BEAN. Uromyces fabae, rust; and boron deficiency: La.
V. VILLOSA, VETCH. Ascochyta pisi, leaf spot; Colletotrichum sp., anthrac-
nose; and Peronospora viciae, downy mildew: La. | |
VIGNA SINENSIS, COWPEA. Cercospora vignae, leaf spot: La. Fusarium oxy-
sporum f, tracheiphilum, wilt: La. ~ Macrophomina phaseoli, stem canker:
La. Rhizoctonia solani, stem-canker: La. Sclerotium rolfsii, southern
Wilt: Miss. Mosaic (virus): Miss.
ZEA MAYS, CORN. Fusarium moniliforme: La. (ear rot), Miss. (stalk rot).
' . Helminthosporium sp., leaf spot: Miss. Physoderma zeae-maydis, brown
spot: both Stetes. Puccinia sorghi, rust: La. Rhizoctonia solani,
- damping-off: Miss. Ustilago meydis, smut: both States. Mosaic (virus):
La.
FRUIT AND NUT CROPS “eh
ALEURITES FORDII, TUNG TREE. Rhizoctonia microsclerotia, web blight: Miss.
CARYA ILLINOENSIS, PECAN. Cercospora fusca, brown spot: both States,
Cladosporium effusum, scab both States. Gnomonia nerviseda, vein spot:
Miss. Bunch (virus): La. .
CITRUS NOBILIS UNSHIU, SATSUMA ORANGE. Sphaceloma fawcettii, scab: La.
C. PARADISI, GRAPEFRUIT. Sphaceloma fawcettii, scab: La.
C. SINENSIS, ORANGE. Diaporthe citri, melanose: La.
FICUS CARICA, FIG. Macrophoma fici, canker: Miss. e
The following diseases were noted in La.: Cephalosporium sp., leaf ee
spot; Corticium sp., leaf blight; C. salmonicolor, twig blight; Pelli-
cularia filamentosa (Cortidium microselevotial, 1 leaf blight; P. koleroee
(C, stevensii), twig and leaf blight: Physopella. fici, rust.
- 283
FORTUNELLA JAPONICA, KUMQUAT. ODi.aporthe citri, melanose: Miss.
FRAGARIA, STRAVIBERRY. The following diseases were observed in Lae:
Botrytis cinerea, gray mold; Diplocarpon earliana, leaf scorch; Mycos-
phaerella fragariae, leaf spot; M. louisianae, purple leaf spot; and
Aphelencnoides fragariae, dwarf.
MORUS sp., MULBERRY. Sclerotinia carunculoides, popcorn disease; Miss.
PYRUS COMMUNIS, PEAR. Armillaria mellea, root rot: Miss. Cercospora
Minima, leaf soot: both States. Clitocybe tabescens, foot rot: La.
Corticium salmonicolor, twig blight: Miss. Fabraea maculata, leaf spot:
both States, Septobasidium mariana, felty fungus: Miss. Erwinia amy-
lovora, fireblight: both States. Heterodera marioni, rootknot: Miss.
VITIS spp., GRAPE AND MUSCADINE. Guignardia bidwellii, black rot; and
Rhizoctonia solani: Miss. ;
SPECIAL CROPS
ARACHIS HYPOGAEA, PEANUT. Cercospora personata, leaf spot; and Sclerotium
rolfsii, southern wilt: both States.
GOSSYPiUM, COTTON. Fusarium oxysporum f. vasinfectum, wilt, and Wantn eS
monas malvacearum, angubr leaf spot, were reported in both States.
Verticillium albo-atrum, wilt, was observed in Miss. The ‘following dis-
eases were noted in La.: Cercospora gossypina, leaf spot; Diplodia
gossypine , poll rot; Fusarium moniliforme, seedling rot; Glomerelila
gossypii, es Rhizoctonia solani, damping~-off; Hetercdera ma-
rioni, rootknot; crinkle-leaf ‘associated with high soil acidity and
manganese ae and rust due to potassium deficiency. |
SACCHARUM, SUGARCANE. The following diseases were noted in Lae:
Colletotrichum faicatum, red rot; Cytospora sacchari, sheath rot; _
Fusarium moniliforme, vokkah~-boeng; Pythium sp., root rot; Sclerotium
rolfsii, sheath rot; the virus diseases chlorotic streak and mosaic; and
multiple bud of pee anne cause.
TREES AND CRNALIENTALS
CRATAEGUS sp. Gymnosporangium globcsum, rust: Miss.
GLADIOLUS. Fusarium sp., bulb rot; Pseudomonas marginata, steia rot; and
Heterodera marioni, rootknot: Miss.
IRIS. Mosaic (virus): Miss.
LAGERSTRCEMIA INDICA, CRAPE MYRTLE. Uncinula australiana, powdery mildew:
Miss.
LIGUSTRUM sp., PRIVET. Microspheera alni, powdery mildew: iiiss.
MAGNOLIA GRAUDIFLORA. Meliola amphitricha, socty blotch: Miss.
PHLOX. Ervsivhe cichoracearum, powdery mildew: iiss.
PINUS TAEDA, LOBLCLLY PINE. Systremma acicola, brown spot: Miss.
-POPULUS sp., POPLAR. Melampsora sp., rust: Miss.
’ RHODODENDRON sp., AZALEA. Exobasidium azaleae, sient Sarg Miss.
QOvulinia azaleae, flower spot: La.
ROSA. Sphaerotheca pannosa, vowdery mildew: Miss.
NOS oo SOG ae Sy
SrA cans cae ae: a ie 4 Se ai te aie
donaed W. tare eth assistance of Avkensee Slate | OATS
Plant Pathologists and crop Specialists.
\
. ue Cae - ||
The 1943 season in Arkansas was abnormal in many respects, as seen in the®)
following climatological data (U. S. Départment of Commerce, Weather Bu- ~
reau, See ees Data, Arkansas Division Vol. 48 No. 3, Walter C. |
Hickmon):
Departure from Mean _— Departure from |
Mean temp. long-time average -precipitation long-time averag AS
Jane 41.8 +0.6 1.00 +3631 3
Feb. hed +3.9 1.00 2.36
Mar. h6.9 -5.6 5.66 $12.04
April 62.9 +1.4 2520: ian 1.73
May | tbe +1.8 7.89 #2495
June TD, Bot +267 PP Ze sel -1,19
July S269 ° #223 Lk 2659
Aug. Sh.e6 go ens Rea HS SAE, 2.53
Sept. 70.4 3.9 3223 “0608? ©
Oct. 61.3 a8 S16 Ae +0027
According to Dr. V. H. Young, the climatological conditions that pre- —
vailed during this year produced clear-cut examples of the effect of a
weather on diseases, and the major facts regarding parasitic and non-para-_
Sitic diseases were determined by the adverse weather conditions. — aq
Severe freezes during. early March nearly destroyed the Elberta peach —|
crop. Estimations of losses, in commercial orchards, resulting from these
freezes range from 50 to 75%. Spinach plantings were also injured by the
freezes of March, A reduction in the strawberry crop resulted fromthe
low temperatures that prevailed near the middle of April. During the lat-
ter part of April and early May the moisture in the soil began to be de- ~
pleted thus hindering the germination of .seeds and growth of crops; dry |
weather further injured the spinach and strawberry crops and greatly de- —
layed the planting of corn, cotton, peanuts, and other truck crops. The a
development and dissemination of fungi were also hindered during this
period, this was especially true of "blue mold" of spinach. In early May
(8-11) torrential rains brought the moisture curve to a very steep peak, —
causing floods, poor stands in various crops, and still more delay in the
planting of other crops. The usual procedure of spraying apples, grapes,
and peaches was impossible because of soft ground. Rainfall then declined
rapidly and almost no rain fell until late in the fall, resulting in one ©
of the most serious droughts in the recent history of the Stete,.
‘ The months of June, July, and August were extremely dry, and hot weatil
persisted causing various crops to deteriorate... In August the precipita-
tion was less than 30% of normal. Cotton opened prematurely; corn and ot
crops showed signs of burning due to the extreme drought. a
285
Late maturing crops benefited from the cool days in September and Octo-
ber but fall planted cereals made poor growth. The precipitation during
these 2 months was nearly normal.
VEGETABLE CROPS
CAPSICU! ANNUUM, PEPPER. Fruit spot (Alternaria sp.) was prevalent in
pepper plantings during 1943. In most of the large plantings a loss of
nearly 10% could be attributed to this disease. Many secondary organisms
entered the Alternaria lesions, causing further decomposition of the fruit.
Wilted pepper plants collected in the vicinity of Van Buren, revealed a
Fusarium upon culturing. A loss of nearly 5% of the plants to this infec-
tion was estimated.
Southern blight (Sclerotium rolfsii) was found in several plantings
throughout the State during 1943. In 2 plantings a loss of nearly 10%
could be attributed to this disease.
Verticillium wilt (Verticillium albo-atrum) was the most widespread dis-
ease of pepper in Arkansas during 1943. affected fields were observed in
several localities in which the causal organism was Verticillium albo-
atrum. Losses due to this disease fluctuated from a trace in some e plant-
ings ings to 35% in the most severely affected field.
_ CITRULLUS VULGARIS, WATERMELON. Fruits affected by anthracnose (Col-
letotrichum lagenarium) were found in two or three plantings in the State.
In one planting a loss of nearly 5% could be attributed to this disease.
Blossom-end rot (non-parasitic) was found without any trouble in all of
the plantings surveyed. Commercial plantings as well as home garden plant-
ings were infccted and many fruits were lost. Many secondary organisms,
such as. Rhizopus, Penicillium, aspergillus, etc., were observed in the
primary injury caused by blossom end rot.
Wilt (Fusarium oxysporum f. niveum) (F. bulbigenum var. niveum) was ob-
served in but a single planting in arkansas during the 1943 scason. In
this particular planting a susceptible varidy was see&d.. The loss, however,
was less than 5% in a planting of 125 acres.
_ CUCUMIS MELO, CANTALOUP. Leaf blight (Alternaria cucumerina) (ilacro-
sporium cucuierinum) was present in all of the plantings surveyed. ‘hile
it probably was the most serious disease of cantaloup seen during the past
season, the extent of injury was very light as the extreme drought pre-
vented the spread of the disease, although the primary infection was wide-
spread. The most severely attacked planting had a loss of over 15% of
the foliage due to necrotic areas.
Downy mildew (Pseudoperonospora cubensis) was found on the older leaves
of a few plants but was causing very little injury. Early infections were
observed in 2 plantings but due to the adverse weather conditions the
primary infections failed to develop further. |
Bacterial wilt (Erwinia tracheiphila), as observed during 1943, was
limited to 3 plants in a small planting of less than an acre.
TPOMOEA BATATAS, SWEETPOTATC. Black rot (Endoconidiophora (Cératosto-
_-mella) fimbriata) of sweetpotatoes was observed in only 3 plantings in
- southern Arkansas. The loss in each of these plantings was less epee 1%.
during the ont season was Mee Ee ot, eee SE oli bates
tas)(F. bulbigenum var. batatatis). In commercial plantings the losses
fluctuated from a trace up to 15%. In one small home planting a Loss of
nearly 40% was observed.
fk loss of 10% was attributed to leaf spot (Phyllosticta eee in one
planting consisting of 75 acres. Most of the plants in this beg
were infected. .
LYCOPERSICON ESCULENTUM, TOMATO. (Fusarium oxysporum f. Lyeopersici) (F.
bulbigenum var. lycopersici) was found to be fairly widespread in the |
State, causing losses fluctuating from 10 to 25%. i
Leaf spot (Septoria lycopersici) was present in most of the plantings _
surveyed, especially in the northwestern part of the State. Severe de-
foliation occurred in the early part of the season; however, owing to the «3
adverse summer weather conditions, late infections were prevented. a
Rootknot (Heterodera marioni) was found in several plantings in northwestem -
Arkansas, the loss in this area ranging from 2 up to 20%. Ina commercial
planting near Summers rootknot nematode affected 20% of the plants ina
5O-acre planting.
Tomato mosaic (virus) was widespread in Arkansas but caused very little
damage. In all of the plantings examined but one, infection was limited
to only a few plants. In the most severely attacked | ae Ze plane
were infected with mosaic in a 2-acre planting.
Drouth injury and sun scald (non-parasitic) were the cause of the great-
est losses to the tomato industry in Arkansas during the 1943 scason. In
some fields sun scald was much more. abundant than blossom-end rot and re-—
sulted in discarding fully 50% of the picking... .(H. R. Rosen).
Blossom—cend rot (non-parasitic) was extremely prevalent and widespread
during the 1943 season in Arkansas. Examples of this condition were found
in nearly every planting surveyed. In some fields as much as 25 to 35%
of the oicking had to be discarded due to blossom-end rot.
PHASEOLUS VULGARIS, BEAN. Anthracnose (Colletotrichum Lin@contninnte)
was very prevalent on the first snap bean crop where Michigan-grovm seed .
was planted. Losses of from 75 to 100% of the crop were not at all uncom- 4
mon. No losses were observed in those plantings in which the seed used Was
‘western-grown. (J. R. Shay)
Leaf snot (Cercospora sp. vresumably cruenta) was ehacruea an 2 ores
plantings. Very little loss resulted from these infections other than a
slight reduction in the leaf area, : R
Powdery mildew (Erysiphe polygoni i), which has frequently been serious. on: |
the late bean crop, was not reported this year, possibly because there Was 4
almost no lete crop owing to dry weather. (V. H. Young). a
Wilted bean plants (Fusarium sp.) was observed in 2 plantings in northern
Arkansas. The amount of loss due to these infections was less than ies “a
although wilted plants were not difficult to find in either planting. ¥
Several dead plants revealed sclerotia of Beteroti um bataticola, however
none of the plants was lodged.
Bean rust (Uromyce's phaseoli var. typica) (U. appendieni ney was seen
in a garden in Fayetteville on climbing beans. It was apparently ‘of no
importance during the 1943 season. (V. H. Young)
287
A 100% bean mosaic (virus) infection was observed in a 40-acre planting
in southwest Arkansas during the past season.
SOLANUM MELONGENA, EGGPLANT. Wilted plants were collected from 2 plant-
ings during the past season and Fusarium was isolated from their vascular
systems. In the most severe case a loss of nearly 15% of the plants re-
sulted in a 3 1/2 acre planting. Southern blight (Sclerotium rolfsii)
was observed causing a loss of nearly 15% in one planting,
CEREALS AND FORAGE CROPS
MEDICAGG SATIVA, ALFALFA. Leaf.spot (Pseudopeziza medicaginis) was dif-
ficult to locate. Specimens were found in plantings in northeastern Arkan-
sas; however, very little loss resulted from these infections.
Rust (Uromyces striatus var. medicaginis) was observed in several plant-
ings in northeastern and southwestern Arkansas. Inthe planting most
severely attacked a loss of 5 to 10% was observed.
ORYZA SATIVA, RICE. Cercospora leaf spot (Cercosvora oryzae), was the most
prevalent and widespread leaf spot on rice in Arkansas during the 1943.
season. Injury to affected plants was confined primarily to the reduction
of leaf area.. A marked difference in varietal susceptibility of the var-
ieties grown commercially in Arkansas was observed. In 2 or 3 plantings. of
Blue Rose and Zenith varieties losses of 4O to 60% of the photosynthetic
area were attributed to this leaf spot. Nira and Arkansas Fortuna varieties
were resistant. |
Leaf smut (Entyloma oryzae) was not very prevalent during 1943 in Arkan-
sas; however in one planting a loss of nearly 1% covld be attributed to
ties disease. Kamrose, Prolitic, and Zenith varieties were observed af-
fected by lear smut.
Brown spot (Helminthosporium oryzae) was found in most of the plantings
surveyed. In most instances, however, only a few spots were apparent on
the leaves and glumes. The amount of damage in most plantings was negli-
gible. In plantings in new rice areas. where susceptible varieties were
_ seeded moderate infections with losses from 3 to 5% were observed. The
greatest loss was observed where black rice infected with brown spot con-
taminated a planting of the variety Prolific.
Stem rot (Leptosphaeria salvinii) was not very serious in most of the
plantings; however, in 2 vlantings, in fields that had been seeded to rice
for 3 or 4 years in succession, losses of nearly 5% were observed. In
several crosses in the nursery plantings in Arkansas losses were greater
than 10%,
Blast (Piricularia oryzae) was limited to plantings in new rice land and
where susceptible varieties were seeded. Losses of nearly 20% were ob-
served in areas.where rice had been planted for the first time. Three
. Varieties, Prolific, Blue Rose, and Lady Wright, were observed with cna
symptoms on the leaves and heads.
White tip (non-infectious) is still prevalent in the rice growing regions
of Arkansas; although most of the rice growers are planting varieties that
are less susceptible to this condition. One field of the variety Blue Rose
revealed white tip to such a degree that a loss of 10% was estimated,
Straighthead (non-infectious) was one of the most. serious maladies of rice
in Arkansas during the 1943 season. In 2 plantings nearly 50% of ther i.
estimated yield was lost due to this condition.
Sun scald (non-infectious) was observed dn: large plantings during the
1943 season. The characteristic symptom, white heads devoid of kernels,
was observed with an estimated loss of nearly 50% in each of the plantings.
SOJA MAX, SOYBEAN. Frog-eye leaf spot (Cercospora sojina) was found
in 3 plantings and present only as a few spots in each instance, and the
amount of loss was negligible.
Pod and stein blight (Diaporthe phaseoli var. sojae) was widesoread in > |
Arkansas curing 1943, and considerable damage was done in certain plantings.
A loss of nearly 2% could be attributed to this fungus in 3 of the affected
plantings,
Loss due-to vilt (Fusarium oxysporum f. tracheiphilum) (F. yu eieeaaeee
‘var. tracheiphilum) never exceeded 1%, although it was not difficult to
locate wilted plants in several of the plantings surveyed,
Anthracnose (Glomerella glycines) was observed causing slight damage to
nursery Ee oie but the disease was era sie in only a single commercial
planting where the loss was negligible.
Downy mildew (Peronospora manshurica:) “was found on a few leaves in 2
‘plantings during the past season. Very little loss could be attributed
to this disease as only a few leaves were found infected within a single
variety.
Lodging due to charcoal rot (Scelerotium bataticola) was observed on early
maturing varieties. In no instance, however, was the loss greater than 1%.
Late-maturing varieties were showing symptoms of charcoal rot but lodging
had not occurred at the time of the last survey of the season. 3
Infections of bacterial blight (Pseudomonas glycines) were observed dur-
ing the 1943 season. In many plantings moderate to severe defoliation oc-
curred as a result of blight infections in combination with the pustule
disease. In degree of distribution and prevalence, blight was less than
the bacterial pustule disease in Arkansas during the 1943 season. \
Bacterial pustule (Xanthomonas phaseoli var. sojense) was the most wide-
spread and prevalent disease of soybean in Arkansas during the 1943 sea-—
son, In 3 or 4 plantings severe defoliation resulted. There was very
little difference in susceptibility of the various varieties grown com=
mercially in Arlcansas, although onelate planting of the variety Cgden was
relatively free from the disease,
In nursery plantings throughout the State large numbers of plants of
several varieties were attacked by mosaic (virus). In one variety in the
nursery planting at Clarksdaie, all of the plants were attacked. Affected
soybean plants were observed in most of the commercial plantings surveyed;
however, the loss was negligible.
SORGHU:i VULGARE, SORGHUM. Milo disease (Pythium arrhenomanes) was ob-
served in several plantings, but causing no loss greater than 1%. — Suscepti-
ble varieties were grown in all of the’ plantings where loss was sustained. 3
Covered kernel smut-(Sphacelotheca sorghi), as observed in 1943, was Hl
limited to 2 plantings and was very sparse in.development. In one of the *
plantings a loss of less than 1% could be attributed to it. Only.a few ~@
heads were found infected in the other plantings. i
Bacterial spot (Pseudomonas syringae) and bacterial streak (Xanthomonas —
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289
holcicola), were observed in nearly all of the plantings surveyed. The
amount of damage inflicted by these bacterial diseases was negligible,
‘although in some plantings they were widespread. Lodging due to the char-
coal rot fungus (Sclerctium bataticola) was observed in early maturing
varieties. A loss of less than 2% could be attributed to this fungus.
Most of the sorghum, however, had been planted since the early floods and
had not matured at the time of the last survey of the 1943 season.
VIGNA SINENSIS, COWPEA. Leaf spot (Yercospora cruenta) was prevalent
and widespread during the 1943 season in Arkansas. In most of the plant-
ings moderate to severe infections were observed. In one olanting the
photosynthetic surface was reduced nearly 60%. Severe defoliation occurred
on. the variety Big Blackeye early in the season; however, in most of the
plantings defoliation was too late to cause a great deal of loss.
Wilt (Fusarium oxysporum f. tracheiphilum) (F. bulbigenum var. trachei-
philum) was observed in 3 plantings where susceptible varieties had been
seeded. Losses in these plantings were estimated at nearly 3%.
Charcoal rot or lodging (Macrophomina phaseoli). The pycnidial stage,
Macrophomina phaseoli, was very prevalent.on cowpeas during the 1943 sea-
son, The only variety to show any apparent resistance to the disease was
the variety fron. Considerable loss resulted from the infections due to
this fungus, in commercial plantings up to 5% and in small variety plant-
ings in nurseries as high as 30%.
Bacterial canker (Pseudomonas syringae) was observed in 4 areas during
~ 1943. Losses fluctuated from a trace up to 5%. In none of the areas was
infection as severe as that observed in Oklahoma. hat
Leaf and .od blight (Xanthomonas phaseoli) [? Pseudomonas syringae | was
limited to a few plants in 2 plantings; the loss was negligible.
Plants infected with mosaic (virus) were observed in one small planting.
Very little loss resulted. | |
ZEA MAYS, FIELD CORN. Ear rots (Diplodia zeae, Fusarium moniliforme,
and Gibberella sp.), were found in some degree in all of the plantings sur-
veyed. Losses varied from a trace in some plantings to 2 or 3% in the
most severely attacked plantings. Diplodia and Fusarium infections were
found in plantings scattered throughout the State; whereas Gibberella was
observed in the area near Clarksdale, Examples of stalk rot caused by
Diplodia zeae were observed late in the 1943 season at Fayetteville.
Leaf spot (Helminthosvorium turcicum) was found quite frequently during
the 1943 season, The amount of damage was regligible in all of the in-
fected olantings.
A leaf spot infection was observed in which the associated Helmintho-
[Burkholder describes the organism causing a similar disease of cowpeas
‘in Texas as Xanthomonas vignicola n. sp. (Phytopath. 34: 430-432. Apr.
1944) See also Hoffmaster (Phytopath. 34: 439-441. Apr. 1944)].
* [Burkholder (1. ce.) states that he has not been able to obtain infection
» of cowpeas in inoculations with X. phaseoli].
290
sporium sp. did not resemble closely the species usually reported attack-
ing corn. |
Root injury (Pythium sp.), resembling very closely the symptoms charac-
teristic of the milo disease of sorghum, was observed causing losses in 3
or 4 plantings,
Brown spot (Physoderma zeae-maydis) was observed in all of plantings.
surveyed in the southern section of the State. In various plantings a
reduction in leaf area up to 5% could be attributed to the causal fungus.
Corn rust (Puccinia sorghi) was not severe and was more or less limited
in its distribution during 1943. Infections were observed in northwestern
Arkansas where the extent of damage was very slight. In no instance was
the leaf area reduced more than 1%,
Corn smut (Ustilago maydis) (U. zeae) was general in its distribution
throughout each olanting. T The extent of the injury fluctuated very little
in the fietds observed, infection usually resulting in a loss of approxi-
mately 5%. ! :
Charcoal rot (Sclerotium bataticola) was present and observed in some
degree in all plantings surveyed, especially in early maturing plantings.
Losses fluctuated from 1 to 10%. Characteristic infection of bacterial
wilt (Bacterium stewartii) was found in one planting during 1943. The
damage was icss than 1%. The insect vector was present in large numbers
in this planting. ‘ | :
FRUIT CROPS
AMYGDALUS PERSICA, PEACH. Peach scab (Cladosporium carpophilum). As a
result of the late severe freeze (larch 3) in Arkansas very few peach
fruits of the early varieties were set. Therefore, an extensive estimation |
of the loss due to scab on the varieties could not be determined. Foliage
infections were quite prevalent throughout the State with the exception of
well-sprayed orchards in the Crowley Ridge area. Fruits on late maturing
varieties afforded a good source of examples of peach scab. A loss of.
nearly 2% of the fruit in orchards near Hope could be attributed to scab;
-however, only the primary stages of the disease were apparent, no cracking —
or coalescing of the spots on the fruit being evident. . In the cxperimental ©
orchards at Hove most of the fruits were attacked by the scab fungus and ~
showed primary and secondary stages of the disease.
Brown rot (Monilinia (Sclerotinia) fructicola) was prevalent on fruits
still clinging to the trees at Hope, and the mummies present on the trees
as well as on the ground revealed that infection in this region had been
fairly heavy. Indications of brown rot were present in the large orchards ~
on Crowley's Ridge; however, the marketable fruit had been harvested.
Bacterial snot (Xanthomonas pruni) was one of the most common diseases
of peach during the past scason. Most of the trces in the severely in-
fected areas were defoliated to the extent that 9/10 of their leaves had ;
dropped. Fruit infections were apparent in several regions of the State. —
FRAGARTA spp., STRAWBERRY. Drought injury was the cause of severe losses
of strawberry plants in most of the strawberry plantings in the State. .
A loss of. ncarly 100% of the plants in several plantings in Jhite Count
was observed,
-.
291
Examples of leaf scorch (Dendrophoma obscurans) were observed in 2 plant-
ings in white County. The amount of damage done by these infections was
negligible. .
Leaf spot (Mycosphaerella fragariae) was prevalent in two or three plant-
ings in White County. A loss of 10% of the leaf area, due to necrotic
spots, was observed. Only a few plants were observed and collected reveal-
ing characteristic symptoms and signs of the red-stele disease (Phytoph-
thora fragariae). The infections were limited to 2 small garden plantings
and the disease was not found in the commercial plant-growing area of the
State.
MALUS SYLVESTRIS, APPLE. Sooty blotch (Gloeodes pomigena) was present
in: several orchards observed during the past season. Very little damage
resulted from these infections other than as a grading factor.
The most serious outbreak of apple cedar rust (Gymnosporangium juniperi-
virginianae), was observed in northwest Arkansas, where an orchard of over
L0 acres showed a foliage infection of 20%. Fruit infection was apparent
on approximately 2% of the fruits. Light to moderate defoliation was ob-
served in one crchard in northwest Arkansas.
Fly speck (Leptothyrium pomi) was apparent in orchards in northwest
Arkansas. Very little loss could be attributed to this disease, although
examples could be located without too much difficulty. In neglected or-
chards infection was comparable in extent to that usual for sooty blotch.
Apple blotch (Phyllosticta solitaria) was severe on early maturing sus-
ceptible varieties not properly sprayed. The foliage of Yellow Transparent
variety was heavily infected. Cbservation of blotch on fruit of susceptible
varieties was limited to a few fruits. Dry, hot weather reduced: the infec-
tions on late maturing varieties; however, blotch was found on several
susceptible varieties causing a loss of nearly 2%.
’ Black rot (Physalospora obtusa) was one of the most serious diseases of
unsprayed apples observed in Arkansas during the 1943 season. In such or-
chards losses of 5 to 15% were estimated. Characteristic frog-eye leaf
spots were apnarent in most of the orchards surveyed, as well as fruit and
twig infections.
Brown rot (iionilinia (Sclerotinia) fructicola), in most instances, was
associated with injury to the fruit, either mechanical or insect injury.
“Loss was negligible. _ .
Apple scab (Venturia inaequalis) was still noticeable in well-sprayed
orchards throughout the State; however, losses of less than 5% were esti-
mated. Infections fluctuated from a trace to 20%.
Fireblight (Erwinia amylovora) was light in most of the regions surveyed.
In one locality the infection could be considered moderate.
PRUNUS spp., CHERRY. Leaf spot (Coccomyces hiemalis) was the only dis-
ease observed on cherries in Arkansas during the 1943 season. The extent
of the loss was less than 5%. In one orchard in northwest Arkansas slight
defoliation resulted. |
_. RUBUS spp., CANE FRUITS. Anthracnose (Elsinoé veneta) was well establish-
ed in plantings scattered throughout the blackberry-growing region of the .
State. The most severe infections were located in the northwest section.
The losses fluctuated from 5 to 10% in most of the plantings.
Orange rust (Gymnoconia peckiana) is one of our most serious blackberry
)\ oF wy oe ey ee Fe Oe aie. \
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292 | iad | co ae
diseases which causes moderate losses but is not in evidence law in the
season, It was very prevalent early in the 1943 growing season. (Vv. H.
Young).
Leaf spot (Septoria rubi ) was severe enough in many tees to. cause
moderate defoliation. In 2 plantings a loss of nearly 15% of the foliage
area resulted,.
VITIS spp., GRAPE. Black rot (Guignardia bidwellit) was of .considera-
ble importance, Weather conditions in May and early June favored it and»
continued rains prevented proper timing of sprays. The hate ee
have been much worse if normal rainfall had continued into ditliye: © (Ne Tee
Young).
In several of the plantings scattered throughout the grape growing
region, black rot infections were not at all uncommon. Leaf and fruit
infections were observed in nearly all of the plantings surveyed. Esti-_
mated losses ranged from 5 to 25%, and in one planting to nearly 50%.
Downy mildew (Plasmopara viticola) was limited in its distribution, as
observed during the 1943 season. Primary infections were observed in
several plantings, but further, development of the disease was prevented by
the adverse weather conditions, Downy mildew was observed on a few rire:
in one planting, late in the season.
SPECIAL CROPS
ARACHIS HYPOGAEA, PEANUT. Leaf spot (Cercospora arachidicola and Cer-
cospora personata) was found in most of the plantings scattered through-
out the State. In plantings near Ozark, in the Arkansas River "bottom
land" leaf spot infections were observed causing considerable defoliation.
Both species, of Cercospora were present in this area. Other plantings —
throughout the State shawed fewer infections. The peanut crop was planted
too late and had made little growth when dry weather set in and finally
gave very low yields. Leaf spot failed to develop except in very favorable
places and actually caused little injury over most of the State.
Specimens of peanuts with’ stems attacked by a: pycnidial fungus were cute q
lected near Parkin. Culture studies revealed that the causal organism was
Diplodia frume¢nti. Loss due to this fungus in the infected area was near-
ly 5%.
Specimens of peanuts infected by a root pope ne une end collected. in
late July and early August. While microscopic and culture studics sug-
gested that the infections were due to Rhizoctonia it is probable that.
Sclerotium rolfsii was the primary cause of this disease. Very little loss —
could be attributed to these infections. Specimens of dead peanut plants
collected in the same field, late in the growing season, by Professor Young —
and sent to Dr. B. B. Higgins of the Georgia Experiment Stations: were
identified by the latter as southern blight. "
GOSSYPIU!: HIRSUTUM, COTTON. The outstanding features of the cotton dis=. @
ease situation were (1) delay in emergence and planting from carly drouth; —
(2) serious losses in stands from floods, washing, wet-spots, and damping-
off; (3) scrious nematode injury in sandy soils; (4) less Fusarium wilt —
than usual’, owing apparently to hot, dry weather. We have noted this in
previous drouth years; (5) less angular leaf spot, anthracnose on bolls,
293
and other boll injury, owing to dry weather; (6) very serious injury from
drouth and deficiency troubles. (V. H. Young).
Leaf spot (Alternaria sp.) was widespread and very prevalent during the
past season in Arkansas. Leaves infected by this fungus were apparent in
early August, suggesting that some ioss may be attributed to this disease.
Alternaria infections were primary in many instances and in several cases
secondary in nature.
Leaf spot (Cercospora sp.) was extremely prevalent and widespread during
the 1943 season. Moderate to severe defoliation occurred early in August.
Cercospora leaf spot, as observed this season, may have caused some reduc-
tion in the yield of cotton; however, in most seasons defoliation due to
Cercospora leaf spot occurs late and has very little, if any, effect on
yield. According to Dr. Young late summer leaf spots in Arkansas are, re-
gardless of the fungi present, only secondary to non-parasitic troubles,
1.¢., drought injury, potash deficiency, and probably other deficiencies in
some cases, and would be of minor importance if adverse soil or weather
conditions were not present.
Wilt (Fusarivm oxysporum f. vasinfectum) (F. vasinfectum) was observed
in 20 countics in Arkansas during the 1943 season. This is not to suggest
that cotton wilt is limited to these counties in Arkansas, but mcrely means
that plantings in these counties were observed and found to be infected
with this disease. The infections varied from 1% to nearly 30% in the
most severcly attacked plantings.
Root rot (Phymatotrichum ommivorum) had previously been reported from a
very limited area in Little River County. ‘Root rot was observed on "black
land" west and south of Foreman, Arkansas. The ooserved distribution dur-.
ing the past season ineluded scattered specimens from Foreman southwest
into southeastern Oklahoma. The degree of damage sustained in various
plantings fluctuated from 2 to over 10% depending upon the location of the
planting. The most severe infection was observed in the lowland southwest
of Foreman.
Wilt (Verticillium albo-atrum) was observed in 5 plantings scattered
through the State; aiways, however, associated with heavy alkaline soil.
The loss due to Verticillium wilt was far less than from Fusarium wilt.
The amount of loss fluctuated from a trace in one planting to nearly 3% in
the most severcly infected planting.
Angular leaf spot (Xanthomonas malvacearum) was observed in some degree
in many of the plantings surveyed. In one or two plantings in southwestern
Arkansas slight defoliation resulted from early infections. Although ahun-
dance of inoculum was present early in the season, late infections were
difficult to find, owing to adverse weather conditions prevailing during
most of the growing season.
Primary infections of bolls due to this bacterium were difficult to lo-
cate. Very few infected bolls were found.
Rootknot (Heterodera marioni) was observed causing some damage in north-
east Arkansas. A loss of nearly 1% could be attributed to rootinot in 2
plantings near Newport.
Rust (potassium deficiency). Cotton plants were observed in several
plantings showing signs of potassium hunger during 1943.
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29h
SUMMARY OF PLANT DISEASES OBSERVED IN MISSOURI DURING 1943
si i poe
Lee ee PA ere ee eS
The following summary of estimates on the plant disease losses in Mis-
souri for the year 1943 is based on the rather limited observation of ) a
the writer, supplemented by the observations of Dr. C. M. Tucker, Depart-
ment of Botany, W. R. Martin and J. W. C. Anderson, Extension Spcdalists
in Horticulture, of the University of Missouri, and Ivar Twilde of Jeffer-
son City, lWissouri, in charge of Barberry: Eradication in this State. In
general it has not been possible to report the trend of the plant disease
situation during the growing season, nor the relative severity of the
various diseases in the different sections of the State, owing to the late
start of the Emergency Plant Disease Prevention Project and the eon
time snent in the different areas.
The weather was unusual in several respects during the growing season.
The severe temperatures and frequent frosts during March and April were,
in general, very damaging to the fruit trees, except in the case of apples.
The wettest May on record occurred in 1943. Rains began on May 6 and oc-
curred almost daily until the 2lst, after which intermittent showers fell
at frequent intervals until the close of the month. Monthly amounts were
‘generally heavy to excessive, particularly over a wide belt extending
diagonally across the State from the southwestern corner to the east-
central bounary. Torn and other cultivated crops suffered gencrally from
too much moisture and lack of cmiltivation. In general al! crops on bot-
tom land along the larger streams where flood conditions prevailed were
severely damaged. June was warm and wet over much of the State, further
delaying the planting and cultivation of crops. High water in the major
streams prevailed throughout most of the month and lowlands remained
inundated in most sections. The last week in June afforded the first op-
portunity to get into fields since the last week of May. During July, .
precipitation was deficient in the southeastern and southwestern divisions —
of the State and drought conditions prevailed during the latter half of
the month, particularly in the southwest. August was, in general, hot
and dry, with severe drought prevailing in the southern and southwestern
sections, -Execpt in some south-central areas where severe drought con-
tinucd, conditions of the preceding months were generally relicved during
September and there was some recovery of crops from the effects of the
dry spell. -Subnormal temperatures prevailed generally throughout Septem-
ber. The growing season ended at about the average date for the northern
and central sections of the State, but about one to two weeks carlier than
the average in the southern sections, with killing frosts and freezing i
temperatures about the middie of October.
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296
VECETABLE CROPS
ALLIU:ni CEPA, ONION. This is not a crop of commercial importance in.
the State and its culture is almost wholly confined to home gardens.
Botrvtis allii (neck rot) appeared to be the only disease of importance
and was estimated to have been responsible for only a trace of damage.
UCUMIS SATIVUS, CUCUMBER. The culture of cucumber is for the most part
limited to the home garden, although there is limited production under
glass in the Kansas City area and in truck gardens in this area and near
St. Louis. Erwinia tracheiphila, bacterial wilt, was undoubtcdly the -most
importent disease encountered and probably peas for a 20% reduction
in yield. Mosaic (virus) was considered to be of minor importance and.
responsible for a trace of damage. b
LYCCPERSICON ESCULENTUM, TOMATO. Tomatoes are grown on a commercial
scale in various sections of the State, both in the field and under glass.
Ficld grown tomatoes were adversely affected by the weather in the south- .
western arca where the extended drought and diseases caused a probable 60%
reduction in yield. -In the northern counties, the frequent precipitation
throughout the growing season accounted for a general increase of fruit
rots end Sentoria blight as compared with their prevalence in the average
SEa SON.
Alternaria solani, early blight, was observed effecting the foliage in
a number cf plantings, but the stem lesions were noticeably less common
than in some years. Damage from this disease was considered minor, amount-
ing to no more than a trace.
Colletotrichum phomoides, anthracnose, did not appear to be a serious
problem except in a few isolated instances late in the growing scason.
For the State as a whole, a trace of damage could be attributed to this
disease.
Corynebacterium michiganense, bacterial canker, was observed in only a
few instances on southern-grown stock and, in general, was considered to
be of minor importance, causing a trace of damage.
Fusarium oxysporum f. lycopersici (F. bulbigenum var. lycopersici), wilt,
continues to be an important problem, particularly where wilt-susceptible
varieties arc grown for commercial processing. It was estimated that a
50% loss resulted from wilt infection.
Septoria lycopersici, Septoria blight, was prevalent and scrious in all
sections of the State, causing much defoliation by mid-summer. The yield
of the ‘early pickings was propably not greatly reduced, excent in that
much of the fruit set was lost as a result of severe sunscald. Subsequent
pickings werc noticeably short, however, and of inferior quality. It was
estimated that 15% of the crop was lost because of this disease, ? |
Xanthomonas (Phytomonas) vesicatoria, bacterial spot, was prevalent in
practically all fields, ranging from a trace to as much as 25% of the fruit
affected. It wes decidedly more prevalent in the northern, more moist
counties, The bacterial lesions themsclves do not seriously affect fruit
used for processing, but undoubtedly they provide avenues of entrance for
secondary, rot-producing organisms. A probable loss of 3% was cstimated
to have resulted from this disease.
Heterodora marioni, rootknot, was of importance in local situations,
oe | ; ) 297-
particularly in the southern section, and it appeared occasionally in
northern counties on southern grown planting stock. For the cntire State,
the damage resulting was considered to be of minor importance, amounting
to a trace.
Fruit rots caused by various secondary organisms following sunscald,
growth cracks, insect injuries, etc. were responsible for much loss through-
‘out the season in all sections, accounting for an estimated 15% reduction
Mosaic (virus) was observed. in a few instances but in no case was it a
serious problen. . Probable damage amounted to a trace.
_ Greenhouse-grown tomatoes are subject to certain diseases which do not,
ordinarily, become problems in the field.
Cladosporium fulvum, leaf mold, is undoubtedly the most serious problem
encountered in the culture of tomatces under glass. ._It was estimated that
this diseasc accounted for a 15% reduction in yield.
Despite a somewhat better opportunity to control Fusarium wilt under
greenhouse conditions than is possible in the field, it was estimated to
have caused a loss of 5% in the greenhouse tomato-yield.
Phytophthora parasitica, buckeye rot, is of considerable importance as
a factor in tomato production under glass. It was estimated to have caused
a L% loss. ae
oclerotium sclerotiorum, drop, becomes of major importance in certain
houses from time to time and may seriously affect production. On the aver-
age, however, the probable loss amounted to no more than 12 this pee
season.
Blossom-end rot, (physiogenic), is not uncommon in greenhouse tomato
plantings and it was estimated to have caused a 2% reduction in yicld.
PHASEOLUS VULGARIS, BEAN. The production of green snap beans is limited
almost "entirely to the home garden, although more extensive production
occurs to scme extent in truck gardens near the metropolitan centers.
Fusarium solani f. phaseoli (F. martii var. phaseoli), dry root rot,
was observed but considered to be of minor importance, causing a trace of
damage. Xanthomonas (Phytomonas) phaseoli, bacterial blight, was un-
questionably the most. serious disease problem on this crop, reducing the
yield an esti imeted 20%. Uromyces phaseoli var. typica, rust, was of minor
importance, responsible for only a trace of damage. Heterodora marioni,
rootknot, was important in localized situations in reducing yield, but for
the entire State, was considered to have reduced the yield only a trace.
Mosaic (virus) was observed but considered to be of little importance,
causing a trace of damage.
“SOLANUM TUBERCSUM, POTATO. The most important commercial potato produe-
ing area in the State is located near Kansas City on low-lands, which were
inundated during the spring floods. It was estimated that fully 50% of
the crop was lost, either in the field or indirectly because of tuber de-
cay in transit, as a result of the standing water. The loss due to other
factors was of minor importance.
Actinomyces scabies, scab, was considered to be of little importance,
accounting for a trace of damage. Erwinia phy toput hors ( E. carotovora),
_ blackleg, was estimated to have caused a 1.0% loss, as was Fusarium solani f.
eumartii (Fusarium wilt). Rhizoctonia solani, black scurf, was estimated
to have caused a trace of damage.
298
CEREALS AND FCRAGE CROPS
AVENA SATIVA, OATS. Erysiphe graminis, powdery mildew, was considered
to be of minor importance and responsible for a trace of damage. Fusarium
sp. and Pythium spp.. caused rceot necrosis, a serious and prevalent trou-
ble rcsulting in an estimated 5% reduction in yield. Puccinia coronata, ~
crown rust, was prevalent in all fields but according to the State Barberry
radication Office, was of minor importance as a factor in reducing yield.
A trace of Gamage was attributed to it. Puccinia graminis, stem rust, was
quite Bee a and in some instances severe damage resulted. The State
Barberry Eradication Cffice reported an estimated reduction in yield of
6.5% for the State, Ustilago avenae (loose smut) and U. kolleri (U. levis)
(covered smut) caused a combined loss estimated at 7% of . -the- yield.
HORDEUM YULGARE, BARLEY. Erysiphe graminis, powdery mildew, was of
minor importance and caused only a trace of damage. Gibberella zeae (G.
saubinetii),. scab, was prevalent and caused an estimated 2% reduction in
yield. Helminthosporium sp., Fusarium sp., and Ophiobolus graminis were
associated with foot rot, which was of minor importance and was cstimated
to have caused a trace of damage.
Helminthos port um ramineum, stripe, was responsible for a loss amounting
to a trace, Helminthospcrium sativum, spot blotch, was somewhat more preva-.
lent and scrious than in average years, causing an estimated 5% rcduction
in yield. |
Puccinia anomala, leaf rust, was prevalent in all sections of the State,
but only a trace of damage was thought to have resulted from the disease,
according to the State Barberry Eradication Office. Puccinia graminis,
stem rust, was observed in only a small percentage of fields and was ccn-
sidered to be of no importance in reducing the yield. No loss was reported
by the Statc Barberry Eradication Office. i
Pythium sppd., root nocrosis, was a serious problem and was responsible
for an estimated 10% reduction in yicld.
Rhynchosporium secalis, leaf scald, was of minor inporwenee and caused a
trace of damage,
Ustilago oe (U. hordei), covered smut, was responsible for an esti-
mated 5% loss. Ustilago nuda and U. intermedia, loose smut Ss, were estimated
to have Lge combined loss amounting to 3%.
MEDICAGO SATIVA, ALFALFA. Pscudopeziza medicaginis (leaf spot) and
Pyrenoveziza :ucdicaginis (yellow leaf blotch) are probably the most de-
structive diseases of alfalfa in this region. They were severe on the first
cutting and it was estimated that the yield was reduced 5%.
Rhizoctonia crocorum, violet rcot rot, was reported to be causing some
damage in localized areas, specimens having been sent in to the University
from ‘washington county. .
"Crown rot! due to decay following insect damage was observed in the
northwestern part of the State, affecting 3 to 5% of the stand in certain
fields. It appeared to be a problem only in relatively old stands. The
trouble was diagnosed by the Emergency Plant Disease Prevention Laboratory
at Stillwater, Oklahoma, as secondary decay following injury by the clover
root curculio, Sitona hispidula.
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SECALE CHREALE, RYE. Practically all of the rye planted in the State
is used as a fall and- winter pasture crop and is plowed under in the
spring. The diseases which occur are, therefore, considered to be of minor
importence, except those,influencing stand or affect leaf development.
Claviceps purpurea, ergot, was present to a very limited extent and
caused an estimated loss amounting to a trace. Puccinia rubigo-vera var.
secalis (?, meres) , Leaf rust, was considered to be of minor importance,
a aha of SUp.'s nee ATR cee was the most seriaus
causing pyth tum
disease problem 4
SOJA MAX, SOY BEE gm anighicka Floss. of diseases we were Sah opr on meee”
cept in individual fields, none of the diseases was considered to be par-
ticularly destructive and there seemed to be no apparent differences in
their prevalence in the various sections of the State.
-Diaporthe sojae, pod and stem blight, was observed in approximately 1/5
of the fields examined. In no instance was it destructive and it was
estimated to have been responsible for only a trace of damage,
Peronosoora manshurica, downy mildew, was observed in about half of the
fields late in the growing season. Since the disease appareitly did not
become established until the plants were quite fully developed and the
lesions were in the carly stages of development, probably no more than a
trace of d-emage resulted from the infections.
Pseudomonas (Phytomcnas) glycinea (bacterial blight) end Xanthomonas
(Phytomonas) phaseoli var. sojense (bacterial pustule), were present in
practically every field, but in varying amcunts. Infection ranged from
instances in which only a few of the lower leaves were involved to situa-
tions where 100% of the foliage showed the presence of lesions. In no
case were these diseases considered to be responsible for a great deal of
damage, in thet the total leaf area involved was rather small. It was
estimated that the probable reduction in yield amounted to about 3%.
_ Macrophomina phaseoli [? sclerotial stage], charcoal rot, was observed
affecting plents in only one field in southeastern idissouri, accounting
for a 3 to 54 kill. For the State, the damage would amount to no more than
a trace.
Bud blight (virus ?) wes prevalent in approximately 2/3 of the fields
examined. Its extent varied from field to field. In many, only a few
_ seattcred plants showed the characteristic symptoms; in others, practical-
_ ly all plants showed evidence of infection. In only a limited number of
fields was infection severe encugh to have caused an appreciable reduc-
tion in yicld and it was estim.ted that for the State, no more ‘than a lh
loss could be attributed to the disease. :
-TRITICUM AESTIVUM, WHEAT. Gibberellda zeae (G. saubinetii), scab, was
prevalent and caused an extimated 2% loss. _
Puccinia graminis, stem rust, varied in prevalence depending upon local-
ity and the variety of wheat grown, but in general it was not a serious
problem. it was estimated to have caused a trace of damage for the entire
State, according to the State Barberry fi oeeata on Office.
» Puccinia rubigo-vera var. tritici (P. triticina), leaf rust, was preva-
lent in all lccalities, but the losses resulting were considered to be
negligible, according to the State Barberry Eradication Office. A trace
of ddmege was reported.
_ Pythium snp., root necrosis, was one of the most serious disease pro-
blems, accounting for an estimated 10% reduction in yield.
308
Septoria tritici, speckled leaf blotch was of minor importance, causing
a trace of damage. <
Tilletia foetida (T. pees, ahd T. caries Cie tritici), bunt; caused:
an estimated 1% loss. —
Ustile goo ti “itici, loose smut, was of considerable importance, co
an estimated 6% reduction in yield.
Xanthomonas (Phytomonas) translucens var. undulosa, black chaff, was of
minor importance, causing a trace of damage.
ZEA MAYS, FIELD CORN. Bottom-land corn was subject to frequent and pro-
longed inundation during the spring rains in much of the State and as a
resuit got off to a very late start. Many fields were replanted and some
plantings were made as late as the latter part of June and early July.
Bacterial stalk rot (Phytomonas dissolvens) was a. problem locally in these
excessively moist situations and much of this late planted corn was killed
by the Cetober freezes before it had fully matured. In the southwestern
section, the severe July and August drought stopped the development of the
plants, precluding the possibility of a profitable yield.
Asvergilius spp., ear rot, was relatively common foliowing corn sears
damage, but orobably caused only a trace of damage.
Diplodia zeae, dry rot, was prevalent in all fields except some very
late planted ones in which the plants were still green and immature in
late Gctober, The stalk rot phase of the disease varied in prevalence
from an average of 11% infection in the southwestern, drought-affected
counties to an average of 33% infection in the northern section where more
normal precipitation occurred. Oniy 2% reduction in: yield was estimated
since most of the plants apparently became infected'relatively late ~
and had produced reasonably good ears. The ear rot phase varied little in
the different parts of the State and was estimated to have caused a 1%
loss.
Fusarium moniliforme, ear rot, was prevalent in ae regions, particular-
ly following ear worm damage. Although the percentage of ears infected
was fairly high in some fields, the actual loss was estimted to nave
amounted to ee pe
Gibberella zeae (G. saubinetii), ear rot, was likewise prevalent over the
State, varying considerably from field to field. The average loss proba- —
bly amounted to about 0.5%. :
Nigrospora oryzae, ear rot. This organism was very prevalent and was
found affecting a very high percentage of secondary ears. Since these
ears normally do not develop, this infection may be discounted in estimat-—
int the loss due to Nigrospora. The percentage of primary ears affected
averaged less than 0.5% and it was estimated that the actual damage re-
sulting amounted to a trace.
Penicillium spo., ear rot, was common following ear worm danage. The
loss, however, was estimated to be no more than a trace.
Phytomonas dissolvens, bacterial stalk rot, was important in localized
situations on flooded bottom-lands. No more than a trace of damage was 7
noted by the weiter, although reports were received at the University in- ~
dicating that in a few fields a relatively high percentage of bie was
affected. 7.
Bacterium (Phytomonas) stewartii, bacterial wilt, was observed but con- _"
sidered to be of minor importance, accounting for a trace of damage. He:
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