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Agricultural HF xperiment Station.

ot the Macylan 4d

BULLETIN No. 82.
Ag Cultural Exo er imen C

THE SAN JOSE SCALE.

COLLEGE PARK, MD.

April, 1895.

ear li sire

Z tert ron /

MARYLAND

gricultural egerintent Station,

ADVISORY COMMITTEE OF BOARD OF TRUSTEES.

GOVERNOR FRANK BROWN.........0.. seccseceeee Annapolis.
THE Hon. MARION DE KALB SMITH.......... Chestertown.
THE HON. ‘SPENCER -C2 JONES: ..cc0e tense. e+e Rockville.
THE EON! JAMES Hi; PRESTON. 0.c2)..20eescets Baltimore.
THESEION. DAVID SEEBWRID 1.2. sets-ceecs cate Clear Spring.
CVAVION Je DRNEDI.. 3 ore pete eee Snow Hill.

OFFICERS OF THE STATION.

ROBERT oO Ha MibimmRee sass. Director.

HARRY J. PATTERSON, B.S8..Chemist.

JAS.) FROBINGONgs.snuceoseee Horticulturist.

CAV HRI YS Ce asso Physiologist and Entomologist.
MILTON, WHITNEY .2040c0be. fou Physicist.

SOTHORON Kary, B. S.......... Assistant Physicist.
ERNEST H. BRINKLEY......... Assistant Agriculturist.
JOS. be OWENS, MAD te.0.:. Treasurer.

CHARLES (Ws RIDER sss... 5-2 Stenographer.

Loeated on the B.& O. R.R., 8 miles N. of Washington, D.C.

iN iS) = ee

The bulletins of the Station will be mailed free to any citizen of Mary-
land who sends his name and address to the station for that purpose.
Correspondents will please notify the Director of changes in their post
office address, or of any failure to receive the bulletins.
ADDRESS,

MARYLAND AGRICULTURAL EXPERIMENT STATION,
COLLEGE PARK, MARYLAND,

LETTER OF SUBMITTAL.

MARYLAND AGRICULTURAL EXPERIMENT STATION,

DEPARTMENT OF PHYSIOLOGY AND ECONOMIC ENTOMOLOGY

b]

COLLEGE PARK, MD.
MaRcH 10, 1895.

Srr:—

I take pleasure in submitting herewith a bulletin on the San Jose
Scale, the most important, perhaps, of the insects which now affect the
fruit interests of the State. Another bulletin on some of the inseets
which have lately attracted attention is in course of preparation.

Respectfully yours,

CAV eR iu ny.
To Robert H. Miller, Esq.,

Director, Maryland Agricultural Experiment Station.

INTRODUCTION.

No insect is just now of more importance to the fruit-growers of
Maryland than that which has been designated as the San Jose Scale, a
name, given to it because it first became known, or was first particularly
noticed around San Jose, California. It is exceptionally injurious, usu-
ally causing the death of the affected trees; occurs on a great variety of
deciduous trees and has great power of multiplication. It was only im
the Autumn of 1893 that the presence of this insect, which is one of the
worst with which California fruit-growers have had to deal, was sus-
pected on the Atlantic Coast. It was then thought to be restricted in
its range, and I had hopes that it might be effectually stamped out.
sut during the past year it has been found at, or reported from, so many
new localities in the East, all the way from Florida to New York, in-
cluding the States of Maryland and Virginia, that there is no hope of
being able to exterminate it. It has come to stay, but as it is possible to
very materially limit its injury and spread, and by proper precautions
to preyent its introduction into districts in which it does not yet occur,
[ feel warranted in giving a pretty full account of the species in the
present bulletin.

As will be seen from the context of this bulletin, it is already
reported from points in Charles, Kent, Talbot, Anne Arundel, Prince
George’s, Washington and Frederick counties, Maryland, and it is my earn-
est hope that all into whose hands this bulletin may fall and who recog-
nize the scale upon any of their trees will at once send to the Station speci-
mens with as full account as possible of the extent of the infection, Other
species, not in the same way to be dreaded, will frequently be confounded
with it, and the entomologist will be glad to examine specimens that
may be suspected and make proper report and, where necessary, visit the
localities. It is only by making a thorough survey of the State for
infected centers that we may hope to succeed in limiting or still further
restricting the range of the species, and in this work the fruit-growers
themselves may materially assist by correspondence with the Station and
should do so for their own good.

The illustrations were prepared for the Department of Agriculture

and are used by the courtesy of Secretary Morton.
. Co Vieia

THE SAN JOSE SCALE.
(Aspidiotus perniciosus Comstock.)
A Serious and Recent Importation into Maryland.

Bye Di Ce Wie Radley:

PAST HISTORY OF THE SPECIES.

The following history of the species up to the year 1892, may be re-
produced from my Annual Report as Entomologist of the Department of
Agriculture for 1893.

In the Annual Report of this Department for 1880, Prof. J. H.
Comstock described under the above name,,an insect which he had col-
lected in Santa Clara County, Cal. He stated that from what he had
seen of the species, he considered it to be the most pernicious scale-insect
known in this country. He had never seen any other species so abundant
as this was in certain orchards, and was told that it infested all the de-
ciduous fruits grown in California, except the peach, the apricot and
the black Tartarian cherry. As a remedy he suggested the use of strong
alkaline washes.

Until very recently the San Jose Scale has been confined to the Paci-
fic Coast, but has extended north to Washington, and south to the Mexi-

can border, and has be-
come, perhaps, the chief
enemy to Pacific coasthor-
ticulture. Considerable
attention has naturally
heen paid to the species
_ by California horticultu-
rists.

In 1883, Matthew Cooke
published figures of the
larva, male pupa, and
adult male, together with
the adult female scales
on twig and fruit. He
stated that the insect was
first noticed by fruit ship-
pers as infesting fruit in
1873, at San Jose, Santa
Clara County. From that
time it spread rapidly un-
til 1880, and but little
effort was made to ex-
terminate it. In the win-
ter of 1881-82, crude pe-
troleum was applied ex-
tensively ; in some cases
’ ! with good results, but in

Fic. 1.—San Jose Scale: a, pear, moderately infested— the majority of instances
natural size: b, female scale—enlarged. e e J
—(from Insect Life.) with great harm to the

88 MARYLAND AGRICULTURAL EXPERIMENT STATION.

trees, many trees dying from the effects. The remedies recommended
were one pound of concentrated lye to a gallon of water, and six pounds
of caustic soda to twelve ounces of potash, and eight gallons of water.
‘These remedies were to be applied only at the dormant seasons. While
the tree is in leaf: one pound of whale-oil soap, one-third of a pound of
sulphur, and an ounce and a half of lye or caustic soda to a gallon of
water was recommended.

In 1894 the late Dr. 8. F. Chapin, in his biennial report as State
Inspector of fruit pests, mentioned the San Jose scale, but stated that in
Santa Clara County, where it first appeared, there had been a most gratify-
ing decrease in its numbers, and in the destructive effects following its
presence, both results having been brought about by the intelligent and
well directed efforts of the fruit-growers. He stated that the scale had
been/found at that time in many different localities in the State, but had
not caused any great decrease in orchard products. He urged that the
pest should be watched and treated in its incipiency.

In the biennial report of the State Board of Horticulture of Cali-
fornia for 1885-86, the late W. G. Klee, then State Inspector of fruit
pests, published a short account of the insect, illustrating its character-
istic appearance upon twig, leaf and fruit. Mr. Klee stated that the in-
sect has three distinct broods—one in June, one in August, and one in
October; but that these broods overlap, and in consequence the summer
washes are not thorough remedies unless frequently repeated. He there-
fore recommended winter treatment, consisting of the cutting back and
thorough thinning of all trees above twenty feet in height, together with
thorough scrubbing of the rough bark of the old trees, and the applica-
tion of one-half pound of concentrated lye, one-half pound of commercial
potash, and five quarts of water.

In the Proceedings of the Eighth Fruit-Growers’ Convention, pub-
lished in the report of the State Board of Horticulture for 1887-88, Prof.
C. H. Dwinelle, is said to have reported the most perfect success in fight-
ing the San Jose scale in Sonoma County, Cal. A seriously infested or-
chard was treated with absolutely complete success by means of a wash
composed of one-half pound of commercial potash, one-half pound of
caustic soda, and five quarts of water. This was applied when the trees
were in a dormant condition.

In the report of the same Board for 1889, a reprint is given of Com-
stock’s description in an article upon scale-insects and remedies. Several
formule for summer and winter washes are given, the most successful of
which, and the one which has come into most general use, being the so-
called lime-sulphur-salt wash. This wash consists of forty pounds
of unslaked lime, twenty pounds of sulphur, fifteen pounds of
rock salt, and water to make sixty gallons. The summer washes com-
prise potash and caustic soda, and whale-oil soap and sulphur, with a slight
admixture of caustic soda and potash. In the report of the Board for
1891, Mr. Alexander Craw published an article entitled “insect pests and
their extermination,” in which he briefly discusses this species. He con-
siders it to be a very serious pest of deciduous trees, but states that the

BULLETIN NO. 32, MARCH, 1895. 89

remedies just mentioned are so cheap and effective, that no excuse can be
tolerated for a seriously infested orchard. He further states that a
Chaleid fly(Aphedinus fuscipennis Howard) had been found doing such ef-
fective work in subduing the species in an orchard in the neighborhood
of Los Angeles, that a complete restoration of the orchard was confidently
expected.

In Bulletin 26, of this Division, Mr. Coquillett, in his report of the
scale-insects of California, devotes four pages to this species. He states
that its origin is uncertain, but that the fact of its being so frequently
found upon plants imported from Japan would seem to point to that
country as its original home. He states that the species never attacks
citrus or coniferous trees, and that the LeConte pear, when grawing in
the midst of other varieties of pear, is almost exempt. The twice-stabbed
ladybird (Chilocorus bivulnerus) is mentioned as being the most abundant
and efficacious enemy of the scale, although Mr. Coquillett has never
known an instance where even one single tree has been entirely or very
nearly freed from the scales by the work of this beetle. The article
concludes with a series of experiments with washes. The result of these
experiments was that the resin and caustic soda wash recommended by
Mr. Coquillett, in Bulletin 23, of the Division, was found to be superior
to the others. This wash 1s to be applied only during the dormant
season, and consists of thirty pounds of resin, nine pounds of seventy
per cent. caustic soda, four and a-half. pints of fish oil, and water to
make one hundred gallons.

Mr. Coquillett’s testimony as to the good offices of Chilocorus bivul-
nerus, coincides with that of other observers, but a surprising instance,
which indicates that the species may occasionally prove effective, was
mentioned in Zhe California Fruit Grower, in 1892. It was there stated
that Mr. N. W. Motheral, procured a number of these beetles in San
Diego county, (date not given) and placed them in some orchards in
Tulare county, which were badly infested with the scale. They did not
appear to multiply greatly until the spring of 1892, when immense num-
bers appeared simultaneously and completely cleared the orchards of the
county of the scale.

An interesting ladybird of the genus Scymnus was found in 1892, by
Dr. Blaisdell, preying upon the San Jose scale at the Coronado parks,
near San Diego. This species was described by Dr. Blaisdell, as Scvanus
lophanthae n. sp., but is one of the species imported by Mr. Koebele, from
Australia, and has not proved very effective in destroying the Aspidio'us.

In the September, 1892, number of the Agricultural Gazette, of New
South Wales, Mr. A. Sidney Olliff, reported the receipt of a typical series
of Aspidiotus perniciosus on the fruit, leaves, and twigs of pear from West
Maitland, New South Wales. Mr. Olliff further stated that although
this species had not previously been recorded as occurring in Australia,
it had been known to some fruit-growers for a number of years.

In an important paper read by Mr. Alexander Craw, before the State
Horticultural Society, of California, December, 1592, the San Jose scale
is stated to be unquestionably of foreign origin, and it is further sur-

SO MARYLAND AGRICULTURAL EXPERIMENT STATION.

mised, on the authority of Mr. John Britton, of San Jose, that it was in-
troduced into California upon trees received from Chile by the late
James Lick.

In Bulletin 7,of the New Mexico College of Agriculture, published

in June, 1892, Mr. C. H. Tyler Townsend, entomologist of the station,
-ecords the occurrence of the species at Las Cruces upon apple, pear,
plum, peach, quince and rose, and states that it was brought into New
Mexico on young trees from California. The winter eggs are mentioned
in Mr. 'Townsend’s account as turning orange-yellow in sprihg and hatch-
ing the first or second week in May.

ITS HISTORY IN THE ATLANTIC STATES.

Early in August, 1893, specimens of this species were first brought to —
my attention, while yet government entomologist, by Prof. B. 'T. Galloway,
Chief of the Division of Vegetable Pathology, U. S. Department of Agri-
culture, who received it on a pear sent by Dr. C. H. Hedges, of Charlottes-
ville, Va., who had mistaken it for a fungus disease. Recognizing the
importance of the matter, 1 drew attention to this introduction at the
meeting of the Association of Economic Entomologists, at Madison,
Wis., the latter part of the same month. On the supposition that it
might be restricted to Dr, Hedges’ trees, I took active steps to furnish all
possible information about the subject, and endeavored to interest the
State Board of Agriculture of Virginia. I had the infested region at_
Charlottesville, carefully investigated by Mr, EK. A. Schwarz and Mr, D.
W. Coquillett, whose reports were published in /nsect Life, Vol. 6, pp.
247 and 253. The insect was found upon pear, peach, plum, apple,
quince, rose, currant, gooseberry and raspberry. The careful survey of
the field thus made seemed to justify the belief that this was a local and
restricted outbréak. Ata meeting of the State Board of Agriculture at
Newport, Va., | read a paper upon the subject, urging active measures
for its extermination, and pledging, on Secretary Morton’s account, the
active co-operation of the National Department in such measures.

Believing that the most effective way to exterminate it was by the use
of what is known as the gas treatment, i. e., the fumigation of the trees
under a tent by means of hydrocyanic acid gas, this being known as a
most effective insecticide and most likely to reach and kill all the insects,
ny first efforts were in this direction. It was the first time that efforts,
had been made to employ the gas treatment in the Eastern States, though
this treatment has been used for many years and is very popular in the
orange groves of California. Mr, Coquillett, who had been the agent of

BULLETIN NO. 32, MARCH, 1895. 9]

the Division at Los Angeles and who had discovered and developed this
‘gas treatment, was fortunately with me in Washington at the time, so
that the treatment was entrusted to him. We had some difficulty, in the
first place, in getting the tents manufactured, and still further difficulty
in putting them in operation. There are various contrivances in California
used for the operation of these tents, the simplest of which, perhaps, for aver-
age sized or small trees, are poles with which the two ends of a quadrangular
tent are thrown over the tree, the tree itself supporting the sheet. In
the Charlottesville case the tents were constructed of eight ounce duck
and made in the form of an octagonal sheet, and were oiled with boiled
linseed oil, two of them measuring twenty-eight and the other two forty-
four feet in diameter. The fumigation was subsequently reported to
have been successful in destroying the insect without injuring the trees,
though some of these had already begun to leaf out or were in blossom.
Later developments, however, showed that a few of the sects had escaped
death just as I had found to be the case in the gas treatment at Mont-
serrat.

During the period when the experiments were being made, or during
March and April, 1894, fate had decreed that I should be absent in the
West Indies. After making all due arrangements to havethe work of ex-
termination thoroughly prosecu-
ted, and after having finished my
Annual Report to the Department
in which an illustrated article
upon this San Jose Scale was in-
cluded, I suddenly decided to
make a trip to the West Indies,
more particularly to study two
scale-insects, viz., the Purple Scale
(Mytilaspis citricola) and the Or-
ange Scale (Chionaspis citri) which
under the denomination of
“blights,” had been for some years
killing out not only acres, but
square miles of limes on the Is-

Fig. 2.-San Jose Scale: Apple Branch, with Jand of Montserrat. This trip
scales in situ-natural size.—(from eee
Tnineel ive, was taken at the earnest solicita-

tion of the Montserrat Company,
of Birmingham, England, without any cost to the Department of Agii-

eulture and without any remuneration to myself. The importance of the

92 MARYLAND AGRICULTURAL EXPERIMENT STATION.

matter and the indirect bearing of the results on the management. of
these two scales, which also affect citrus trees in Florida, justified my re-
quest for leave of absence for this purpose. Very thorough fumigation
was being carried on there by an expert, Mr. R. T. Mullard, from Los
Angeles, as the washes usually effective with us, seemed less so there.
The condition of things was most interesting and exceptional, and I felt
that a study of it might prove valuable, not only to the Montserrat peo-
ple, but to our own.

It was during this absence from the Department that specimens of the
San Jose Scale were brought by M1’. E. Dows to Mr. L. O. Howard, my Assis-
tant-in-charge, from Riverside, Charles county, Maryland. He at once had
the matter investigated. Some twenty acres are planted to an orchard which
contains some 2000 peach trees, having some 250 apple trees mixed with
them. The introduction could be traced to the planting in the Spring of
1888, from stock obtained from the old established and well-known nur-
series of John R. Parry, at Parry, N. J. Many of the older trees
were found to be dead, and most of the others badly affected. Adjacent
orchards within a radius of two miles, the stock of which had been ob-
tained from other nurseries, were found to be quite free from the scale.

Later in March further specimens were received at the Department
from De Funiak Springs, Fla. Here the insect, as subsequent evidence
showed, was found not only upon peach and pear, but also upon pecan
and persimmon. Mr. Howard, as Acting Entomologist, now deemed the
matter of sufficient importance to issue a circularof warning. This gave
a summary of the information at hand with certain figures that I had or-
dered prepared for an intended article in /ysect Life. The circular was
widely distributed both directly to Eastern fruit growers and through the
newspapers, and, as a result, a number of new localities of infection were
discovered, and among them Neavitt, Talbot county, Md. The infested
orchard is located on one of the inlets of the Chesapeake Bay and con-
tains about fourteen acres of peach trees, and all of the trees having
been badly affected. So far as investigation could determine, both by
Mr. Coquillett and Mr. Howard, the first trees planted in this orchard
were received from the well-known nursery of my old friends, the Stark
Brothers, of Louisiana, Mo.

Later, Mr. Marlatt discovered another infested locality in Maryland,
on the place of Capt. R. 8. Emory, at Chestertown, in Kent county, and
the original trees were here also traced to the New Jersey nursery afore-
mentioned.

a

BULLETIN No. 32, MARCH, 1899. 93:

The following correspondence is of interest in connection with the
history of the species in the Atlantic States, and may be published now,
since there can no longer be any object in keeping secret the name of
the nurserymen who have been unwittingly instrumental in disseminat-
ing the pest. The Parrys have been most public-spirited in their efforts
to stamp out the species, so far as their own nurseries are concerned, at a
great sacrifice to themselves; and from a verbal report made to me by
Mr. William Parry during the late meeting of the American Pomological
Society in California, I am satisfied that there will be less danger in
future from receiving stock from these nurseries than perhaps from
others which have nt been so thoroughly disinfected.

APRIL 20th, 1894.

Mr. Wm. Parry,

* PARRY. N. J
Dear Str :—

I have just received from a gentleman in Lewisburg, Pa., pear
twigs affected by the San Jose scale and he informs me that the insect
was introduced upon pear trees which he purchased from you, I send
you enclosed a copy of an emergency circular just issued from this
Division, and hope it will induce you to examine your nursery stock and
make every effort to destroy the insect. Above all things, I would
strongly urge you not to send out any nursery stock this spring unless
you are absolutely sure that it is clean. Can you give me the facts (not
for publication, if you have any objection), as to how this scale could
have reached your nursery ? Yours truly,

CoV ean EN.
Entomologist.

“

Parry, N. J., April 25th, 1894.
Pror. C. V. RILEY,

Dept. or AGr., Division oF ENTOMOLOGY, WASHINGTON, D. C.
Dear Sir :—

We are in receipt of your esteemed favor of April 20th, and are
surprised and alarmed to learn we have the San Jose Scale although
from samples sent Professor Smith, of New Jersey State Experiment
Station, he expressed fears such was the case and we have made an
appointment with him to visit our grounds—and as you recommend we
will not send anything of which we have any doubts.

We have no positive evidence how this scale reached us. We have
been in the habit of getting from California fruit and nut trees, prin-
cipally from Japan yarieties and generally imported. From your bulletin

te
94 MARYLAND AGRICULTURAL EXPERIMENT STATION.

I infer it does not attack nut trees nor Japan persimmons. By referring
to our books, I find that in the spring of 1887, we ordered of John Rock,
San Jose, Cala, a quantity of Kelley’s Japan plums. These were
shipped us by order of John Rock from Stark Bros., Louisiana, Mo,
They were received in unsalable condition so that they were not sold by
us but trenched out in nursery rows to recover. They never did recover,
but stood in the nursery two or three years and were dug up and burned,
and my recollection is they were infested with an insect and think it
very probable that it was introduced in our nursery in that way. We
would prefer that our name would not be published in connection with
this pest, as we realize it would ruin our business. We also realize the
danger of distributing any stock infested with it, and have since receipt
of your letter destroyed over $1,000 of young iftrsery stock, fearing,
possibly, it might have been exposed to the same insect. And, hereafter,
will make arrangements to have grown for us such stock as is liable to
the attack until we get rid of it—and grow only that free from it. * *

Thanking you kindly for calling our attention to it and esteeming
any information or assistance you can render usin connection therewith.

I am very respectfully,
JOHN R. PARRY.

Mr. Joon R, Parry, APRIL %%th, 1894.
Pomona NuRSERIES, Parry, N. J.
Dear Sir :—

IT have your long and satisfactory letter of the 25th inst. If you
succeed in more positively ascertaining how the scale reached you, I shall
esteem it a favor if you will notify me. In consideration of your intelli-
gent appreciation of the situation and your promise to avoid further
shipments of infested stock as well as to make every effort to destroy the
insect in your nursery, it will be best, and most in aceord with my own
desires, for the department to say nothing in print regarding the means
by which this insect has become distributed from your nursery for the
present at least. No particular good could be accomplished by it, in
view of your promise, though ultimately the historic fact will have to
be recorded. I shall be glad if you will keep me posted as to the result
of your operations against the insect.

Yours very truly,
Cy Vo iiEnye
Entomologist.

Pror. C. V. Riuey, Parry, N. J., May Ist, 1894.
DIVISION oF ENTOMOLOGY, WASHINGTON, D. G.
Dear Sir :—
Yours received. We think the San Jose scale was introduced into
our grounds by stock (Kelley’s plum) shipped by Stark Bros., Louisiana,

BULLETIN NO. 32; MARCH, 1895. 95

Mo., upon order John Rock, San Jose, vale, as stated in previous
‘ommunication,

We have destroyed nearly all our one feral trees, as well as nursery
rees, of Japan plums which appear to be favorites of the scale. We
have also dug out many large trees of Bartlett, Idaho and other pears.

Professor Smith, of New Jersey Station, visited our grounds yester-
day and probably has reported to you. Should there be any new develop-
ments, or anything of interest transpire in connection with our efforts to
exterminate the scale, will advise you.

tespectfully,
JOHN R. Parry.

The insect formed the subject of two important papers at the Sixth
Annual Meeting of the Association of Economic Entomologists in
Brooklyn the following August. One of these was by Mr. Howard,
giving a full account of the work done by the Department of Agricul-
ture and its results, and the other by Prof. J. B. Smith, of the Agricul-
tural Experiment Station, of New Jersey. Asa result of the discussion
at that meeting, the occurrence of the insect was subsequently established
in parts of Columbia county, N. Y., lying on the Hast bank of the Hud-
son river, below Albany, and in several localities on Long Island.

Still later in the season, as shown by some further notes of the sub-
ject by Mr. Howard, which he has prepared for No. 4, Zusect Life, not
yet out, but of which he has favored me with proofs, other localities
for the insect were discovered, viz., Southern part of Georgia; Clermont
county, Ohio; Neweastle county, Delaware; City Point, Prince George’s
county, Virginia, and at Bristol, Pennsylvania; while three other
localities were added to Maryland, one in Prince George’s county, one in
Anne Arundel county, and one in Washington county.

There can be no question but that future investigation will show
that the insect is quite widely disseminated in many other localities
yet undiscovered, not only in orchards and nurseries, but also in isolated
grounds, and that this general statement will apply to Maryland as well
as to the other States in which it has obtained a foothold; and, while the
energetic efforts that have already been made to stamp it out will go far
toward doing so, we must accept the situation, and acknowledge that the
species has come to stay. While, therefore, I consider that its entire ex-
termination from so many points of infection over so large an area is im-
practicable and not to be hoped for, yet there isno reason why its spread to
other localities may not be very materially, if not entirely checked. This,
howeyer. can only be done by intelligent action, not only on the part of

96 MARYLAND AGRICULTURAL EXPERIMENT STATION.

individuals, but by systematic and concerted action of communities in
the State, made obligatory, if need be, by proper legislation. As prelimi-
nary, a pretty thorough entomological exploration of the State would be
advisable, and, in the meantime, the information conveyed in this bulle-
tin, if widely disseminated, with that which has already gone out from
the National Department of Agriculture, may help to produce the desired
results.
LIFE HISTORY OF THE SPECIES.

In order not to repeat too much in detail the phases of development
common to this and other species of Scale-insects which belong to the
same sub-family, viz: the Diaspine, or Armored-scales, it may be well, in °
this connection, to state a few characteristics which belong to almost all
of them. ‘This sub-family includes many of our worst scale-insects, like
the Red Scale of the Orange in California (Asprdiotus aurantit) the
Scurvy Scale of the apple (Chzon-

aspis furfurus), the Oyster-Shell
~ Bark Louse of the apple (AGtilas-
pis pomorum) and many others.
The young or newly hatched in-
dividuals are almost microscopic
creatures of white or pale yellow
color, with body of oyoid form,
flattened, with six legs, two short
feelers having a varying number
of joints, but rarely more than
eight, and with two filamentous
hairs at the end of the body.
They are active but a brief period,
sometimes but a few hours or even
minutes, rarely more than a day
or two and settle upon the bark
Fig. 3.—San Jose Seale: a, young larva—sreatly near where they are born if there

enlarged: b, antenna of same—still more ,. é

enlarged.—(from Insect Life.) is a chance and it is not already
too thickly covered with the parent scales. A long thread-like proboscis
is gradually thrust under the epidermis and the insect becomes fixed and a
flocculent waxy secretion begins to cover it. ‘This increases until the larva
underneath molts. ‘The first larval skin becomes part of the secretion or
shield and is known as the larval scale and the insect under it after this
first molt loses its legs and feelers, ‘The covering still further increases,

: AMT HVS HTM MTT
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BULLETIN NO, 32, MARCH, 1895, a

and a second molt takes place, and we have a covering which is known
as the medial scale, and which either surrounds or extends from one end
of the larval scale, according to the species. In the male the form of this
scale is usually very much narrower than in the female, and often ribbed;
it is, also, often markedly of a different color, or pure white, while the
female scale is usually darker, or imitates the color of the bark. Thus
the sexes are now distinguishable by their scales or shields while the
insects, themselves, are also readily distinguished at this stage, the male
having transformed to a pupa, with the limbs, feelers and wings for-
shadowed, and the female remaining a mere yellow mass without such
organs,

In the male a third molt takes place under this medial scale, and a
delicate two-winged fly with long feelers and a single anal style backs out
from the rear end. His color is usually pale, with a reddish or dusky
band across the middle of the thorax, and the wings have but two deli-
cate veins, The antenne are variously jointed, the more common nuin-
ber of joints being eight. In the female scale, on the contrary, there is no
particular difference of form after the second molt, She still grows and
is destined to remain underneath her scale, which becomes much larger
and forms what is known as the anal sack. Here after a third molt, she
becomes fertile and either produces her young alive or lays her eggs. In
either case the young in due time issue from the scale, and begin again
the cycle of life, as already related. In those Species in which the scale
is more or less circular, like the one we are considering, the stages of the
scale growth are not so readily separated as in the elongate species which
resemble an oyster or a mussel shell. The larval scale is however, usually
conspicuous, as a central raised point.

The different species of the sub-family are distinguished from each
other not only by the peculiarities of their scales, which do not always
offer trustworthy separating characters, but by the peculiar arrangement
of the secretory pores on a darker and more chitinized anal plate, and by
the peculiarities of the margin of this plate, especially in the female.

Our particular San Jose Scale is quite circular in form, very flat and
pressed close to the bark. It grows from 1-16 to 1-8 of an inch in diam-
eter in the female and about half this size in the male, It has the gen-
eral color of the bark and the larval scale in the centre is a slightly
raised point varying from yellowish to nearly black in color. It is
perhaps, the smallest scale which occurs in Maryland, and is further
¢haracterized and distinguished from all others, which the fruit grower

9s MARYLAND AGRICULTURAL EXPERIMENT STATION.

has to deal with, by producing around the edge a reddish stain or discol-
oration, which penetrates for some depth in the formative tissues of the
bark, and is particularly noticeable when the scales are sparse and not
too crowded, or when upon fruit of an ordinary pale color. Another
peculiarity is, the relatively large size and bright yellow color of the
newly hatched young. Ata short distance, when a branch or a tree is
badly affected and the scales overlap each other, the tree looks as though
it had been covered with lime or ashes, and when crushed or pressed or
scraped the mature insects beneath the scales, if alive or fresh, produce
a yellowish and rather greasy liquid. The accompanying figures, with
the explanations underneath, show very well their appearance upon the
pear, (Fig. 1); their general appearance on an apple branch, (Fig. 2); a
ventral view of the young scale with a larger view of one of its antenne

FIG. 4.—San Jose Scale: male adult—greatly enlarged.—(from Tnsect Life.) -

(Fig. 3); a dorsal view of the male (Fig. 4); and a ventral view of the
female (Fig. 5); with her young developing, and with a large outline of a
portion of the anal plate—the three last figures being very largely mag-
nified and the natural size approximately indicated within an accompany-
ing circle. The ordinary fruit grower would hardly be able to separate
it from several other common insects which have existed in Maryland
from time immemorial, were it not for the smaller size and the reddening
effect which it produces upon the bark.

The observations made in California, as well as those made in the
East and especially at the Department of Agriculture and recorded

BULLETIN NO. 32, MARCH, 1895. 99

in Mr. Howard’s paper already referred to, would indicate that
there are no very exact limitations between the various generations or
_broods of this insect, and that there may be some five annual generations
in the latitude of Washington, each generation occupying on the average
some forty days. The females hibernate in various stages of development
but mostly as mature and impregnated females, since the male does
not hibernate. The speciesis viviparous, i. e., the young are born alive. This
has been made quite clear by the observations in the East and especially
3 at Washington, though some writ-
ers have stated that eggs are pro-
duced. It is quite probable that
both statements may be based on
facts, and that there may be vari-
ation in this respect according to
Posen locality or conditions.
One thing however, is clearly de-
termined, viz. that the species
may be viviparous throughout the
yeal
The large number of genera-
tions is exceptional though there
is some compensation in that the
individual is less prolific than in
those species which produce fewer
or but one annual generation.
The individuals which have hi-
FIG. 5—San Jose Seale: c, adult female contain-bernated acquire full development

ing young—greatly enlarged: d, annal. begin to produce young by
fringe of same—still more enlarged.— ue ee s :
(from Insect Life.) the end of May or the first of June

WV

hy

NG 2 ae
S a)

and from this time on there is a succession of generations. As in almost
all other species of scale-insects the male scales, produced most in Sum-
mer, are, for the most part, formed on the leayes and show a tendency to
gather along the midrib on the upper side.

The matter of most practical importance in the life history of the
species is that 7¢ continues multiplication from the beginning of June until
late in the Autumn, or until Winter weather has fairly set in, and that dur-
ing this time there ts practically no period when the insect will not occur in
almost every condition.

100 MARYLAND AGRICULTURAL EXPERIMENT STATION.

ORIGINAL HOME OF THE SPECIES.

From previous writings upon the subject, more particularly in Cali-
fornia, it has been assumed that this particular insect was derived from
South America and particularly from Chili, but later evidence obtained
by Mr. Howard and brought together in his last communication upon the
subject, (Zusect Life, volume 7, page 290, 291) indicate that it is probably
a native of the Pacific Coast, and that it may have spread thence to those
countries in which it is known to oceur, viz., Chiliand parts of Australia
and the Island of Kauai (where it has been found by Mr, Albert Koebele,)
just as it has been introduced thence into the Eastern States.

PARASITES AND NATURAL ENEMIES.

A widespread and minute parasite which attacks a number of other

seale-insects of the same sub-family was reared from specimens origin-

Fic. 6.— Aphelinus diaspidis How.: greatly enlarged (from Insect Life.)

ally collected at Riverside, Md , and has since been found elsewhere, as
it was also previously known to occur in California. It sometimes does
very effective work. It is a very minute Chalcid-fly (Aphedinus fuscipennts
How.) which the average fruit-grower would not be able to distinguish
from very many others of the same genus, and of which the accompany-
ing figure of an allied species, very much enlarged, will convey a suffi-
ciently accurate idea. The mature fly, having undergone its transforma-
tions beneath the scale, issues from a minute circular hole, and, whenever
such minute and regular holes are discovered upon the scales, the presence
of this, or some allied species of parasite, may be safely inferred.
Another species (Anaphes gracilis How.) which also preys upon allied
scale-insects, and especially on the common Oyster-shell Bark-louse of

BULLETIN NO. 32, MARCH, 1895. LOL

the apple, has also been reared at the Department from the scales taken
at Riverside.

Among predaceous insects which feed upon it, the following are
recorded in my report, as U. 8. Entomologist, as observed at Charlottes-
ville, Va. The common little Malachiid Beetle (Col/ops guadrimaculatus)
was observed feeding in small numbers upon the newly hatched larve.
The Coecinellid beetle ( Pentitia miveZa) and its larvee were very abundant on
the infested trees, and this species, Mr. Schwarz thinks, ita very important
enemy of the scale. The beetles seem to prefer the full-grown female scales,
while the larva feed upon Aspidiotus larvae. The larve customarily trans-
form to the pupa state within the calyx of the pears. This little cavity was al-
ways found literally filled with a mass of young and old scales, full-grown
Pentilia larvee and pups, and recent imagoes. The fact that this beetle,
which is essentially an Eastern species, so readily and effectively began
to feed upon this introduced scale is a very interesting one, entomologic-
ally, and would justify an effort to introduce and colonize itin Californie.

A few of the lady-birds introduced from Australia, have also been
found to prey upon it in California, and especially a steel-blue species,
Orcus australasie, and it would be well to bring specimens to the East.

MODE OF SPREADING.

It follows, from what has already been stated of this and other
allied species of scale-insects, that of their own accord they can spread
but a very short distance annually. Indeed it is a question whether the
insect could ever spread from tree to tree wherever the trees are some
distance apart and the branches do not interlock, were it not for other
agencies which aid them. The principal methods by which these insects
are carried from one tree to another and from one place to another, while
yet in the newly hatched larval condition are, (1) by the agency of wind,
(2) that of running water, (3) by being carried upon the feet or feathers
and hair of birds or other animals, and (4) particularly by means of flying
and crawling insects and gossamer spiders which frequent the same
trees. In this connection I quote the following from my last report as
United States Entomologist:

“Some interesting observations were made by Mr. Schwarz, upon the
transporting of the young Coccid larve by other insects. This very Pen-
tilia was, unconsciously, an active agent in this dangerous work. Hardly
one of the beetles could be found which did not carry on its back at
least one Aspidiotus larva, and sometimes three or four were found upon
a single wing-cover of a beetle. A small black ant (Monomorium minu-

102 MARYLAND AGRICULTURAL EXPERIMENT STATION.

¢um) was adundant upon the pears, attracted by the juice emerging from
the cracks, and almost every one of these ants carried on its back one or
more specimens of the Coccid larvee. Specimens of a little Chrysomelid
beetle ( Zypophorus canellus) were also found upon the trees. Red and
blaek specimens of these beetles occurred, and the interesting observation
was made that while the Aspidiotus larvee crawled freely upon the black
individuals, no specimens were to be found upon the red ones. This
same peculiar fact was also found to hold with the ants, since the red ant
(Formica schaufusst) was abundant upon the pears, but no specimens
were found bearing Aspidiotus larve, while, as just stated, the little
black Monomorium was always found carrying specimens. Curiously
enough, no ladybirds other than Pentilia were seen. The common Twice-
stabbed ladybird (Chzlocorus bivulnerus), which is so active an enemy of
seale-insects and plant-lice throughout the Southern States, was absent.”
The scale-insects are, however, primarily carried to long distances,
while shielded by the scales, through the instrumentality of man, upon
scions and nursery stock. The agency of wind has frequently been noted
in the more rapid spread of the insects in the direction of prevailing
winds. ‘This agency is not only direct, wherever the wind is sufficiently
strong, as in severe storms passing over infested districts at the right
season, butit is also indirect in that the flight of insects bearing the
young scale-insects is also influenced therely. The young scale-insect is
“not easily dislodged from the twig or branch of a tree, but there is every
reason for believing that when the tree is very badly infested so that the
scales are literally piled one upon another, the young lice, finding no
means of support thereon, more readily attach themselves to the bodies
of other creatures or deliberately let themselves drop, to be carried by
wind or by running water, this last means being much more effective in
aiding their spread in countries which are dependent on artificial water-
supply and where irrigating ditches run near or through the orchards.

As already indicated, it has been proved to have been introduced
from California on nursery stock at Parryville, N.J., and there are prob-
ably other centres of infection, ike that in Missouri, from which the in-
sect has been brought directly from California. It would be unjust,
however, to charge the nurserymen with the sole responsibility of this
distribution, because there is every reason to believe that it has been in-
troduced into other localities upon fruit, the rejected rind or peel of
which, carrying the insect, has been thrown out of car windows or from

BULLETIN NO. 32, MARCH, 1895. 103

houses. This conclusion is justified by the frequency with which the in-
sect has been found in our large Eastern markets, upon fruit, especially
pears.

PREVENTIVE MEASURES.

It is obvious, from what has preceded, that most of the influences
at work in helping the insects to spread are essentially local, and would
hardly cause it to overrun the State for very many years to come. Yet,
through man’s instrumentality, there is constant danger of importa-
tion from infested regions long distances away, either upon fruit or
nursery stock. It is, as a consequence, very desirable and necessary that
every fruit grower in the State, whose trees are now free from the attacks
of this pest, should be on his guard against such introduction. Mo fruit
should be brought on from an open market without first being inspected,
and no buds, scions or trees from any nursery should be received without
a similar, first careful inspection.

REMEDIES,

When the emergency circular, already referred to, was issued by Mr.
Howard from the Department of Agriculture, remediai suggestions
necessarily had to be based on past experiments with this species con-
fined to California, and with other species in other parts of the country.
This experience was given in the following form:

Insecticides.—W here trees are found to have become badly infested
the safest and, in the long run, the most economical course will be to cut
them down and burn them, trunk and branch. Where the infestation is
less marked, insecticide washes and sprays may be used, The young lice,
before they have begun to secrete scales (and at this time they can only
be discovered with the help of a magnifying glass), may be destroyed by
spraying with kerosene-soap emulsion. A formula for this mixture fol-
lows:

PRETO S GING Soe cay ersee cece tees scaccotecver-secmrenterens gallons... 2 =67 per cent.
Common soap or whale-oi] soap.............pound....% )-

NV fea fagremece oe ae ties cesar 1 a ch aes eee es gallons... _ 3
Heat the solution of soap and add it boiling hot to the kerosene ;
churn the mixture by means of a force pump and spray nozzle for five or
ten minutes The emulsion, if perfect, forms a cream which thickens
upon cooling, and should adhere without oiliness to the surface of glass.
If the water from the soil is hard, or has a large percentage of lime, add
a little lye or bicarbonate of soda, or else use rain water. For use against
scale-insects, dilute one part of the emulsion with nine parts of cold water.
For the older scales, the washes may be divided into those which can

be used in summer without damage to the trees, and those which are so
strong that they can only be applied during the winter season when the
tree is dormant. None of the summer washes are perfectly cfiicacious, and

Su Deh Cent.

104 MARYLAND AGRICULTURAL EXPERIMENT STATION.

it is doubtful whether any of them will prove of more benefit than the
kerosene emulsion just mentioned. Owing to the fact that we have had
no summer experience with this insect in the East, we can not state posi-
tively the strengths of certain washes which may be used successfully with-
out damage to the trees during the summer. In California, however, one
of our agents, Mr. D. W. Coquillett, has used with success, during the
summer, a resin wash which was made in the fellowing proportions:

PRO SIM tacecvesececebacas elec ss Bakes nas 20d ee ac ese a eee ee ee) COLE LS 20
Caustic soda (yo per cent. streneth). ent On eee 5
SIV] 0% (ov!) Beenie Sree seoab tances cfc tts tenersestoe PICS eaeee ee 3
Wratersufiicient ito "make... ce eee ee gallons......100

It is probable that this mixture will not be too strong for eastern
trees, since, in general, with other insecticides, the climate of California
seems to render trees rather more susceptible to injury than is the case
in the East. For a winter wash the same ingredients may be used in the
following proportions : :

INS OEE te 20 Sits: Sa ee eS pounds... 30
Gaustic soda (70 per cent. Strensth)e..eene,.-e dove 9
OAS IOUS S22 oa cect cc ae aca oe ea neon ee 4%
Waters uiicient. to snake ewseceeee ee ee reece eral gallons......100

The most favored winter remedy in California, however, is the lime,
salt, and sulphur mixture. This is generally used throughout the State
by progressive fruit growers. It consists of :

WiislaRed: line tsc.s.:2i2 222 ere eka Bo Ses vel amet. h) OU nS
‘SiUU |e) 01) (eee eee es aero, Oak ee ee Se MeO EYGIS =
SSUOCKES alt te..-2 sce A ea ge ee ret ened _pounds=-a4.
Water to make. ie wees SALLONS as

This wash will do great damage to the trees if applied during the
growing season, and should be used only in winter. All the sulphur and
half the lime are placed in a kettle, and 83 gallons water added, after
which the contents of the kettle are boiled briskly for about an hour. The
solution, which at first is yellow from the sulphur, will turn very dark
brown, assuming more or less of a reddish tint, and will finally change
from a thick batter to a thoroughly liquid condition, the product being
ordinary sulpbide of lime. All the sulphur is added to the remaining five
pounds of lime and the latter slaked, after which the slaked lime and salt
are added to the sulphide of lime already obtained, the whole being then
diluted with water to make fifteen gallons. This should be strained before
application, as it does not form a perfect liquid solution, on account of the
considerable quantity of undissolved lime, which will soon settle to the
bottom, unless the solution is constantly stirred while being sprayed.

In the experience of the Division in California and Washington,
this solution has not been as successful as could be desired, but it has
considerable popularity among the fruit-growers of California.

The Gas Treatment.—This method has not been extensively used
in California against this insect, but has been used with very consider-

BULLETIN NO. 32, MARCH, 1895. 105

able snecess against the so-called Red Scale upon orange and lemon trees.
It is an expensive operation, but is unquestionably more thorough than
spraying. ‘Trees infested with different kinds of Aspidiotus have been
entirely freed by a single application of this gas.

The treatment consists in enveloping the tree in an air-tight ‘tent
and afterwards filling the tent with hydrocyanic acid gas, generated from
fused potassium cyanide, sulphuric acid, and water. This gas is much
lighter than air and as soon as generated rapidly rises and fills the
tent. It is of course fatal to all forms of animal life, and care must be
exercised in using this treatment. The tent is usually constructed in
the form of an octagonal sheet, of what is ordinarily known as 8-ounce
duck, and is afterwards oiled with boiled linseed oil.. A tent of this
kind, measuring 40 feet in diameter, will cost about $50, and other sizes
in like proportion. Almost any glazed earthenware vessel will answer
the purpose of a generator. The potassium cyanide used is usually of
60 per cent. strength and the sulphuric acid is of the ordinary commer-
cial brand. The proportions are, 1 ounce by weight of cyanide 1 fluid
ounce of the acid, and 3 fluid ounces of water. This is sufficient for 150
cubic feet of space inclosed by the tent.

The water is first placed in the generator, the acid added, and after
the generator is placed under the tent the cy anide is added to the solu-
tion. The cost of the chemicals mentioned is small. The tree is sub-
jected to the action of the gas for about half an hour. In treating trees
10 feet high or less, the tent can be placed over the tree by hand, but
for those of greater height than this some sort of apparatus must be used
for the purpose of elevating the tent over the tree. An apparatus in the
form of a tripod, with a pulley at the top, serves this purpose very well.

The following table of the relative amount of ingredients to height
and girth of tree top will be found useful:

Height Diameter | Water Sulphuric | Potasisium |
of tree. (of tree top. : acid. | eyan de.)
| |
Feet. Feet. | Fluid ozs. | Fluid ozs. Ounces.
6 4 | 7 | $ | 4
8 6 | 2a 1 |
10 8 43 | 22 | Q1
12 10 8 4 4
ie, | 14 | 16 8 8
14 10 10 5 5
14 | 14 | 19 | 94 94
16 12 16 8 8
16 16 29 144 144
18 14 26 13 18
Q 16 | 36 18 18
22 18 | 52 26 26
24 20 | 66 38 33 |

The best results will be obtained by treating the trees during the
colder portion of the year or at night, as the gas is more liable to injure

L106 MARYLAND AGRICULTURAL EXPERIMENT STATION.

the trees when used in very warm weather than it is when the weather is
cooler.

The very poisonous character of the potassium cyanide itself and of
the hydrocyanic acid gas must be strongly impressed upon those who un-
dertake to use this treatment for the first time. The cyanide must be
kept where children and animals can not get at it; it must be kept in
tightly closed vessels, and must be plainly labelled “ Poison.”” During the
process of treatment every care must be taken to prevent human beings
or domestic animals from inhaling the gas.

Judging from the experiments at Charlottesville, Va., under the
auspices of Mr. Coquillett, and from those which were conducted so-
extensively in Montserrat on limes, even this gas treatment fails to
destroy all the eggs where the insects are at all thickly crowded on the
tree, so that a single fumigation can hardly be depended upon to be per-
fectly effective in extermination. I learn also from Mr. Howard that
the pear trees seem to have materially suffered in the cracking of the
bark, as a consequence of this gas treatment.

Summer and Winter Washes.—It so happens, also, that the
different insecticides vary in their efficacy according to climatic and other
conditions, and there is yet a wide field for careful experimentation
bearing on these differences. In an address recently given before the
American Pomological Society at its late session (Jan. 30, 1895,) in Los
Angeles, Cal., I commented on these facts in the following language,
which may be repeated in this connection :

“We must know the effect of a specific insecticide, or a certain mix-
ture, upon the vitality of a given plant at a particular time of day, ata
particular season, with a particular sun exposure, and under certain
conditions of the plant, both as to vigor and exposure. “We must know
how different species of plants are affeeted under the same conditions.
We have much to learn yet as to the possibilities of combining a fungi-
cide and an insecticide. In some cases this combination may be made
with great advantage, in other cases it is just as clear that no advantage
has been derived. But what I wish particularly to call your attention
to, is that all these different insecticides will act somewhat differently
according to the varying conditions indicated, and that experience
between the states east of the Rocky Mountains and the Pacific Coast is.
more particularly conflicting. The kerosene-emulsions, and especially
the whale-oil kerosene-emulsions, haye proved of the utmost value in the
warfare against the scale-insects of the East; while some of the washes,.
especially your winter washes, which haye, according to the best of evi-
dence, given satisfaction to you, haye proved, by contrast, of much less.

BULLETIN NO. 32, MARCH, 1895. 107

value with us in the East. This has been particularly noticeable in a
series of experiments which I conducted during the years 1893 and 1894,
through Messrs. Marlatt, Coquillett and Pergande, and the results of
which are embodied in a paper by the former, /vsect Life, Vol. VII,
pages 115-126). Some of the reasons for these varying experiences are
not far to seek. Asa State, California has many peculiarities, especially
this, the southern portion of the State. It is essentially the land of
scale-insects, and why? In the East the majority of our most injurious
species produce but one generation annually, and the periods of hatching
and developing, and the stages in which hibernation takes place are pretty
definitely marked. Thus, for a period of about two weeks, generally in
the month of May, all the young will hatch from eggs that were hiber-
nated under the female scale. And by spraying the plants affected dur-
ing this comparatively brief period, when the young and tender insects
are so easily destroyed, the plants are, for the most part, easily protected-

“The species which hatch out very irregularly and produce more than
one generation annually are the exception there. Here with you, on the ,
contrary, all your most injurious species go on multiplying the year round,
and there is scarcely any definite demarkation between the different broods,
or the periods of hatching or the different stages of development. ‘There
is hardly any absolute period of rest, properly speaking, to be compared
with the winter period of from four to nearly eight months in the East.
Thus the winter washes, more particularly, vary in their effect in the two
sections, as the scales in the East, being more thoroughly dormant, are
not so easily killed.”

It is evident, from the irregular and continuous production of the
young of the San Jose scale during the summer months that the summer
washes, useful if repeated with sufficient frequency, can hardly be
depended upon to exterminate the insect or entirely rid the tree
affected with it. The necessity of their frequent use makes them,
also, more expensive. Any treatment that will be effective by
one application is preferable, especially if this can be applied in the
dead of the year when other horticultural operations do not command
so much time. Hence our chief reliance must be on what are known.
as winter washes, or on the gas treatment already described.

The lime-salt-and-sulphur wash which is used with so much satis-
faction against this insect in California proved much less satisfactory in a
series of experiments which I had made during the winter 1893-1894
both on the Department grounds on other species of armored scales and
on my own place at Sunbury. The experiments were made on American

108 MARYLAND AGRICULTURAL EXPERIMENT STATION.

and Japanese Euonymus affected by Chzonaspis cuonymi as also on a
hedge of Japanese quince affected by the common Scurvy Scale Chionaspis
Surfurus. 'The resin washes were also found in experiments upon the
same insects to be less effectual than they are in California.

The results since obtained at the Department of Agriculture give a
very high relative value to the ordinary commercial whale-oil soap, ap-
plied at the rate of two pounds or more to the gallon of water, and next
to this the resin wash used five or six times stronger than indicated in
the ordinary formula. My own more recent experience this winter con-
firms the efficacy of the strong whale oil soap solution. Unfortunately
both these washes are expensive, but in this as in so many other things
the best, even if the most expensive, is the cheapest.in the end, and
where trees have already become infested by this pernicious insect they
will be very likely to succumb in the end, unless some remedial measures
are taken or unless some special efforts are made to introduce and
encourage the parasites and natural enemies already treated of.

Mr. Howard, in his latest article, already referred to, summarizes
in the following record a series of experiments in- November and Decem-
ber, 1894, under rather disadvantageous circumstances, becanse of heavy
rains intervening:

Whale-oil Soap.

1. Three pounds dissolved in one gallon of water. Fatal to all the scales on the
trees sprayed with it.

2. Two pounds in one gallon of water. Same result.

3. One and one-half pounds in one gallon water. Fatal to ninety per cent. of the
scales.

4. One pound in one gallon of water. Fatal to eighty per cent. of the scales.

5. One-half pound in one gallon of water. Fatal to one-half the scales.

Resin Wash:

6. Six times summer strength. Resin, 120 pounds; caustic soda, 30 pounds; fish-oil,
15 pints ; water sufficient to make 100 gallons. Fatal to all the scales on the tree sprayed
with it.
7. Four times summer strength. Resin, 80 pounds; caustic soda, 20 pounds; fish-oil,
10 pints; water sufficient to make 100 gallons. Fatal to eighty-five per cent. of the
scales.
Kerosene Emulsion.

8. Pure. Fatal to ninety per cent. of the scales.

9. One part of emulsion and one of water. Fatal to eighty per cent. of scales.

10. One part of emulsion and two of water. Fatal to one-half the scales.

ll. One part of emulsion and three of water. Fatal to thirty per cent. of scales.

12. One part of emulsion in four of water proved fatal to only a small percentage of
scales. (On potted plants in Insectary.)

13. One part of the emulsion in six of water, fatal to a very small percentage of
scales. (On potted plants in Insectary.)

BULLETIN .NO. 32, MARCH, 1895. 109

Hard Laundry Soap:
14. Two pounds dissolved in one gallon of water. Fatal to eighty-five per cent. of
the scales.
15. One and one-half pounds in one galion of water. Same result.
16. One pound in one gallon of water. Fatal to sixty per cent. of the scales.
17. One-half pound in one gallon of water. Fatal to twenty per cent. of scales.
18. One-fourth pound in one gallon of water. Fatal to ten per cent. of scales.
Concentrated Potash Lye:
19. Two pounds in one gallon of water. Fatal to eighty-five per cent. of scales.
20. One pound in one gallon. Fatal to seventy-five per cent. of the scales.
21. One-half pound in one gallon. Fatal to one-half the scales.
22. One-fourth pound in one gallon. Fatal to twenty per cent. of the scales.

Fish-oil Soap, Home-made:

23. One and one-half pounds in one gallon of water. Fatal to half the scales.
24. One pound in one gallon. Fatal to twenty per cent.
25. One-half pound in one gallon of water. Fatal to five per cent. of the scales.

Oregon Winter Wash:

26. (Ordinary strength.) Sulphur, 15 pounds; slaked lime, 15 pounds; bluestone, 1%
pounds; water sufficient to make 100 gallons. Fatal to acomparatively small percentage
of the scales.

27. (Double strength.) Sulphur, 30 pounds; slaked lime, 30 pounds; bluestone, 2/2
pounds; water sufficient to make 100 gallons. Quite a large percentage of the scales
escaped destruction.

California Lime-sulphur-and-salt Wash:

28. (Ordinary strength ) Sulphur, 25 pounds; lime, 50 pounds; salt, i8 pounds; water
sufficient to make 100 gallons. Fatal to a comparatively small percentage of the scales.

29. (Double strength.) Sulphur, 50 pounds; lime, 100 pounds: salt, 86 pounds; water
to make 100 gallons. A rather large percentage of the scales not destroyed.

Nore.—Experiments 8 to 11 and 14 to 25 were followed in from seven to ten hours
after the application of the washes by a hard shower of ten or fifteen minutes’ duration.
Experiments 3 to 7 had been on the trees a little over twenty-four hours previous to this
rainfall. The other experiments were of earlier date, and were not influenced by rains
for a considerable time after the applications were made.

Insecticide Apparatus.—In Bulletin No. 23, of the Station, in
treating of the best means of spraying apple trees for preventing the
ravages of the Apple Worm or Codling Moth, I have given some account
of the machinery required in connection with the use of the arsenites.
On large trees and for orchards the same machinery will apply for the use
of the washes and emulsions just treated of for scale-insects, and may
be repeated here.

A good, strong double-acting force pump should be purchased and
mounted on a large stout barrel with the supply tube reaching well
down to the bottom. It has become the custom to mount the pump in
the end of the barrel, but except in the case of the Nixon Tripod, it will
be almost as easy to mount it on the side of the barrel, which is easily
held in place by a skid near either end, and is then more compact and
stable than when standing on the end while the handle of the pump
comes lower and is more easily worked.

It will be well to buy the pump without the attachments. About
25 feet of } inch cloth insertion rubber tubing is attached to the discharge

110 MARYLAND AGRICULTURAL EXPERIMENT STATION.

orifice, or to each of the orifices in case there are two. To the end of the
tube is fitted one of the modifications of the Cyclone or Riley nozzle and
the outer 8 or 10 feet are clamped or wired to a light pole or bamboo
fishing rod for convenience in elevating the nozzle into the larger trees.
The tank or barrel is mounted on a cart or sled and driven between the
tree rows, one man driving and pumping and other holding and directing
the extension pole and nozzle.

I have mentioned the cyclone nozzle for the reason that, all things
considered, I believe it, in some of its modifications, to be the best for
orchard work. The Climax nozzle manufactured and sold by the Nixon
Nozzle & Machine Company is also a good nozzle, but it is rather large
and clumsy, its spray hardly so fine, and it will not answer for fungicides
containing lime, since it clogs easily. The Vermorel modification of the
Cyclone nozzle possesses a little attachment which quickly unclogs
the orifice when once stopped up, and is therefore preferable. More-
over, neither the Cyclone nor the Vermorel modifications is patented,
W hich, other things being equal, is in their fayor. Both are manufact-
ured by Thomas Somerville & Sons, Washington, D. C., and Robert
Leitch & Sons, also of Washington, or may be made by any brassand iron
worker from the descriptions in my official reports.

For application to nursery stock or to smaller trees one of the
smaller hand-pumps advertised by various manufacturers, especially
pump-makers, as hydronets or aquapults, will answer the purpose, though
better still would be the use of what are known as knapsack pumps.—

The price of these ranges from $10.00 to $20.00.
IMPORTANCE OF THE MATTER: FINAL ADVICE.

It is very doubtful whether the fruit-growers of the Eastern States
or whether those of Maryland have yet awakened to a realization of the
importance of taking active measures to stamp out if possible, this
pernicious scale-insect, or at least to protect from it trees not yet affected.
It has been introduced within comparatively few years, and there is
therefore, an excellent chance of restricting its range, or of ridding
particular orchards of it. Prof. J. B. Smith, Entomologist of the
New Jersey Experiment Station, has issued a special bulletin upon
the insect, which is more widely distributed in that State than elsewhere
in the East and which, in fact, as we have already seen, has been largely
distributed to other parts from that State. He closes his bulletin with
a series of recommendations which have been very widely distributed and
even copied in the official bulletins of other states, and which, though
excellent in themselves, are, I fear, rather calculated to discourage those
who have extensive orchards to disinfect. The chief of these recom-
mendations are as follows:

BULLETIN NO. 32, MARCH, 1895. gigi

First. “Every orchard that has been set out within the last six
years should be thoroughly examined to ascertain whether or not the
scale is present.

Second. If it proves to be present and is confined to a few trees,
the trees had better be taken out and destroyed, unless the infestation is
so slight that the trees can be gone over with a stiff brush and all the
scales actually brushed off.

Third. If the orchard is young, and the trees are not too large to
be handled, it will be best to use a stiff brush and, taking each tree
separately, brush off all the scales. This looks like a good deal of
mechanical work ; but it will pay in the end. It can be doneat any time
during the winter; it will be absolutely effective and, with care, there
need be no further trouble from this insect in an orchard so treated.

Fourth. If the trees are too numerous to be treated by hand, or
are too large to be conveniently handled, prune back liberally, removing
as much wood as the tree can easily spare. The cuttings should be carted
off and burnt as a matter of precaution, and what remains of the trees
should be. washed with the potash solution above described. This should
be done as soon as may be, and a month later, during a moderately mild
spell, the trees should be again treated, this time with the kerosene emul-
sion, made as above described and diluted five times. The object of this
double treatment is, first, by means of the potash to dissolve or corrode
the scales to a greater or less extent, and to kill off a considerable pro-
portion of the insects themselves. At the end of a month the potash will
probably have been washed down and all dissolved away, so as to exert
no further action. ‘The scales, however, will be thinned down, riddled or
loosened from their hold, and an application of the kerosene emulsion
then made will give it abundant opportunity to reach the insect. If both
these materials are applied thoroughly, the kerosene will finish any work
left undone by the potash and not a single specimen need escape.

I have serious doubts whether anything is to be gained by the stiff
brush treatment urged by Prof. Smith, involving, as it does, an infinite
amount of labor and the severe pruning which he conjoins with it, since
crushing off the scales is impracticable on the smaller twigs and branches.
Any winter wash that is effective will obviate the necessity for this pre-
liminary labor.

The other treatment recommended is most valuable, but requires two
sprayings, viz., one of the potash solution and one of the kerosene emul-
sion. As a result of later experiments the past winter, as set forth tn this
“bulletin, tt becomes evident that any thorough spraying of the two-pound-to-the-
gallon-solution of the whale-otl soap will be perfectly effective, and may be
depended upon as a substitute for the treatment urged by Prof. Smith. Cost
of materials and convenience in obtaining will otherwise influence each
individual in the choice of the comparatively few satisfactory winter
washes, as indicated in this bulletin.

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THE SAN JOSE SCALE.

A SERIOUS AND RECENT. IMPORTATION INTO MARYLAND.

GABLE OF CONT Bb hwiks:

PAG
imtroduction, Counties affected in Maryland... 2. .200... scams necececsewn cies . 86
feaspellistory, Of THE SPeCles. .2.-.-<.eseqqe- sete semana secs sieececa eae Bese Oil
Its History in the Atlantic States.................0sseeeeeeeeceeer eee seeeeeees 90
Wihen first ascertained to occur im Maryland... i... 00s2 ise. vedsmcesamentes 92
Distributed from: Parry, New Jersey....5.:-.- 02-00) erscecsesese nna rnverscesas 93
Life History of the Species.........-......00-..0+ gutastan sence jem eee 96
Its important peculiarities from a practical point of view............... 99
Original Home of the Species........+.seeeseseveseeeeee eee ees eee eseeeeeee sees 100
iMeeearasitessand natural, Hmeniles......n.c2 00s. cee ew ances cisistne sale eepenenewee 100
Mode of spreading........2....ceseseceeesersecrereececcenerencceeceacnsessecsceees 101
Preventive Measures..........0ssesseseeee sabaslec dese seraciine sactine seeennaceomanet 103
EMOTES, wsiarsna's Goines y 00 «esi'ecloncinierecs ost neuisiea bi omneslepae Aeoeaie ae naeoers eaee seit 103
Summer and effective Winter Washes............c.sccsececesoeseceeeneerrnerse 106
The most important Washes.........-..ssseeeseseeceseecesceeeeere esse een ence 108

Importance of the matter: best way to eradicate ; final advice........... 110

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