• TABLE OF CONTENTS
HIDE
 Title Page
 Personnel
 Table of Contents
 Figures
 Brief history
 Scale discovered
 Fields examined
 Source of insect
 Infested nurseries
 Occurence in the east
 Varieties of fruits infested
 Remedies
 Life history
 How the insect spreads
 Recommendations
 Conclusion














Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 29
Title: The San Jose scale
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027176/00001
 Material Information
Title: The San Jose scale
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: p. <89>-111, <2> leaves of plates : ill. ; 22 cm.
Language: English
Creator: Rolfs, P. H ( Peter Henry ), 1865-1944
Publisher: Florida Agricultural Experiment Station
Place of Publication: Lake City Fla
Publication Date: 1895
 Subjects
Subject: San José scale   ( lcsh )
San José scale -- Control   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: P.H. Rolfs.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027176
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000919946
oclc - 18154354
notis - AEN0339

Table of Contents
    Title Page
        Title Page
    Personnel
        Page 90
    Table of Contents
        Page 91
        Page 92
    Figures
        Figure 1-2
        Figure 3-4
    Brief history
        Page 93
    Scale discovered
        Page 93
    Fields examined
        Page 94
    Source of insect
        Page 94
    Infested nurseries
        Page 95
    Occurence in the east
        Page 96
    Varieties of fruits infested
        Page 96
    Remedies
        Page 97
        Page 98
        Page 99
        Page 100
        Page 101
        Page 102
        Page 103
    Life history
        Page 104
        Page 105
        Page 106
        Page 107
    How the insect spreads
        Page 108
        Page 109
    Recommendations
        Page 110
    Conclusion
        Page 111
Full Text


Bulletin No. 29.


FLORIDA -



AGRICULTURAL EXPERIMENT

STATION.




THE SAN JOSE SCALE



P. H. ROLFS.



The Bulletins of this Station will be sent free to any address in
Florida upon application to the Director of the Experiment
Station, Lake City, Fla.



JACKSONVILLE, FLA.
VANCE PRINTING COMPANY.
1895.


-&ugust, 1895.
















BOARD OF TRUSTEES.


HON. WALTER GWYNN, President .. . Sanford
HON. W. D. CHIPLEY, Vice-President ... .Pensacola
HON. F. E. HARRIS, Ch'n Executive Committee Ocala
HON. A. B. HAGAN, Secretary . ... .Lake City
HON. S. STRINGER . ... Brooksville
HON. C. F. A. BIELBY . . .. .DeLand
HON. J. F. BAYA . . Lake City




STATION STAFF.


O. CLUTE, M. S., LL. D . . Director
P. H. ROLFS, M. S . .Horticulturist and Biologist
A. A. PERSONS, M. S . . .Chemist
C. A. FINLEY. . . Director's Secretary
A. L. QUAINTANCE, M. S .Assistant in Biology
H. K. MILLER, M. .. Assistant in Chemistry
JOHN F. MITCHELL .. .Foreman of Lake City Farm
J. T. STUBBS . Supt. Sub-Station, DeFuniak Springs
W. A. MARSH . .. .Supt. Sub-Station, Fort Myers











THE SAN JOSE SCALE.


TABLE OF CONTENTS.
Brief History.
Scale Discovered in Florida.
Fields Examined.
Source of Insect.
Infested Nurseries.
Occurrence in the East.
Varieties of Fruit Infested.
Remedies:
Kerosene Emulsion, formula.
Resin Wash, formula.
Kerosene Emulsion and Resin Wash compared.
Resin Wash-application of.
Spray Thoroughly.
Do not use winter Resin Wash in winter in the
latitude of Florida.
Kerosene Emulsion discussed.
Comparison of cost of two remedies.
Spray During Dry Season.
Persistency of Pest.
Natural Enemies.
Life History.
How the Insect Spreads.
A Practical Illustration.
Caution.
Send Specimens.
Recommendations.
Conclusion.




























CL
Figure 1-a. San Jose Scale on a California pear-natural size.
b. Female Scale as seen from above-enlarged.


b


Figure 2 -San Jose Scale on apple branch, showing natural size, and number ;
above and to the left, scales enlarged.

































d

Figure 3 -c. Adult female containing young-greatly enlarged.
d. Anal fringe of same still more enlarged.


Figure 4 Adult male of San Jose Scale-greatly enlarged.


These illustrations were kindly secured for us by L. 0. Howard, Chief ol the
Division of Entomology, U. S. Dept. of Agriculture.













SAN JOSE SCALE.


(Aspidiotus Perniciosus, Com.)
This insect was brought into California about 1870.
It is thought to have been brought from Chili. About
1873 it was known as the San Jose Scale from its inhab-
iting the San Jose district. In 1880 Prof. J. H.
Comstock collected it and named it as above. By 1892
this insect had spread through all the fruit-growing
regions of California, and northward into Oregon and
Washington. While it was being imported to our State,
about that time, no one seemed to be acquainted with the
pest.
It resembles the less destructive scales so much that
its introduction and spread among the growers of decid-
ious fruits at DeFuniak was not looked upon with suspi-
cion until it had made serious inroads into orchards, and
had killed out at least one. The ordinary long scale of
the apple resembles this insect so much, to the untrained
eye, that several orchardists insisted that it "never did
any harm on our apple trees."
When it was learned through Insect Life that this
pest had made its appearance in the East, dilligent atten-
tion was paid to all orchards that were reported as not
doing well.
SCALE DISCOVERED.
While taking part in a farmers' session of the Cha-
tauqua at DeFuniak, Mr. G. W. Mellish handed me some
specimens of infested twigs that were at once suspected as
93













SAN JOSE SCALE.


(Aspidiotus Perniciosus, Com.)
This insect was brought into California about 1870.
It is thought to have been brought from Chili. About
1873 it was known as the San Jose Scale from its inhab-
iting the San Jose district. In 1880 Prof. J. H.
Comstock collected it and named it as above. By 1892
this insect had spread through all the fruit-growing
regions of California, and northward into Oregon and
Washington. While it was being imported to our State,
about that time, no one seemed to be acquainted with the
pest.
It resembles the less destructive scales so much that
its introduction and spread among the growers of decid-
ious fruits at DeFuniak was not looked upon with suspi-
cion until it had made serious inroads into orchards, and
had killed out at least one. The ordinary long scale of
the apple resembles this insect so much, to the untrained
eye, that several orchardists insisted that it "never did
any harm on our apple trees."
When it was learned through Insect Life that this
pest had made its appearance in the East, dilligent atten-
tion was paid to all orchards that were reported as not
doing well.
SCALE DISCOVERED.
While taking part in a farmers' session of the Cha-
tauqua at DeFuniak, Mr. G. W. Mellish handed me some
specimens of infested twigs that were at once suspected as
93








being cases of San Jose Scale. On taking these to the
laboratory at Lake City the suspicion was confirmed by
a study with the microscope. As a report of the presence
of this insect would be very damaging to any fruit-grow-
ing section specimens were forwarded to Mr. William H.
Ashmead, an entomologist investigator in the United
States Department of Agriculture, so as to avoid any pos-
sible mistake. Mr. Ashmead pronounced it the San Jose
Scale. This was the first intimation that the entomol-
ogist of the Department of Agriculture had of the presence
of this pest in Florida. On April 7, 1894, they pub-
lished a notice of the presence of this scale at DeFuniak.
I intended to publish a notice of the same nature in the
agricultural papers, but as the above-mentioned notice
appeared before our notice was mailed it was not sent
out.
FIELDS EXAMINED.

As soon as it was definitely known that the pest was
in the State, the Experiment Station Entomologist was
sent at once to the infested orchards to ascertain to what
extent the insect had spread, and also to learn just how
badly the orchards were infested.
On examination several orchards were found to be
infested to such an extent that it seemed unprofitable to
work on them. Out of about 1,200 acres of orchards that
lie around DeFuniak, 160 or 200 acres were found to be
infested.
SOURCE OF INSECT.

After locating the infested orchards, and noting the
severity in each of them, dilligent inquiry was made to
ascertain the source of infection. It was at first thought
the pest came from a single orchard and that it possibly
originated from a single tree, but further study showed
that this was not the case, but that some infested nursery








being cases of San Jose Scale. On taking these to the
laboratory at Lake City the suspicion was confirmed by
a study with the microscope. As a report of the presence
of this insect would be very damaging to any fruit-grow-
ing section specimens were forwarded to Mr. William H.
Ashmead, an entomologist investigator in the United
States Department of Agriculture, so as to avoid any pos-
sible mistake. Mr. Ashmead pronounced it the San Jose
Scale. This was the first intimation that the entomol-
ogist of the Department of Agriculture had of the presence
of this pest in Florida. On April 7, 1894, they pub-
lished a notice of the presence of this scale at DeFuniak.
I intended to publish a notice of the same nature in the
agricultural papers, but as the above-mentioned notice
appeared before our notice was mailed it was not sent
out.
FIELDS EXAMINED.

As soon as it was definitely known that the pest was
in the State, the Experiment Station Entomologist was
sent at once to the infested orchards to ascertain to what
extent the insect had spread, and also to learn just how
badly the orchards were infested.
On examination several orchards were found to be
infested to such an extent that it seemed unprofitable to
work on them. Out of about 1,200 acres of orchards that
lie around DeFuniak, 160 or 200 acres were found to be
infested.
SOURCE OF INSECT.

After locating the infested orchards, and noting the
severity in each of them, dilligent inquiry was made to
ascertain the source of infection. It was at first thought
the pest came from a single orchard and that it possibly
originated from a single tree, but further study showed
that this was not the case, but that some infested nursery







had sent a shipment of trees, and the indications are
that there have been repeated importations.
The first orchard in which they made their appear-
ance is now practically killed out: there are less than 5
per cent. of the trees remaining, and these are scattered
over the whole field. No efforts were made until last
year to destroy the insects. It is said to be about six
years since the first orchard showed a diseased condition.
It would seem very remarkable indeed if this were
the only place in the State infested, because the nursery
stock comes largely from the same places. However,
only one other location has been found, and this was
stamped out immediately by burning the infested trees.
As this was on stock only one year from the nursery, the
loss was not very heavy. The nursery that sent the
stock out was visited immediately, but no trace of scale
could be found on the premises. Just how the trees
became infested could not be learned.
If there are no other districts in Florida infested by this
scale it seems quite probable that no new importations will
be made. The fruit growers are quite aware of the danger
attending such an introduction, and the nurserymen will
do all they can to keep from receiving such notoriety.
The greatest danger, then, to our State is that the insect
may be present in not a few groves and orchards in
small numbers without the owners being aware of it.
INFESTED NURSERIES.
Competent entomologists have reported two nur-
series in New Jersey. several on Long Island, N. Y., and
one in Missouri. None of the Southern establishments
have been discovered as disseminating or containing
diseased stock, but that should not allow us to be any
the less cautious and suspicious. It does not follow that
because the scale has not been discovered in an orchard
or nursery that it is not there.







It occurred several times, while I was inspecting
orchards at DeFuniak, that only one tree out of a hun-
dred was found to contain any insects at all, but the
presence of a single infested tree is as dangerous to an
orchard as a single case of cholera is to a community.
We have all reason to believe that the dissemina-
tion of diseased trees by nurserymen was entirely free of
any bad intention, and due to an ignorance of the pres-
ence of the scale. As soon as the presence of this pest
was discovered all efforts were made to stamp it out.
OCCURRENCES IN THE EAST.
So far the insect has been found, in the East, in the
following States: Missouri, Indiana, Ohio, Maryland,
New Jersey, New York, Pennsylvania, Virginia, and
Florida. New Jersey and Missouri seem to be largely
responsible for its dissemination in the East. They have
been traced directly from New Jersey to California. They
were brought to New Jersey on some Kelsey plum trees
in 1886 or 1887. While the original trees were destroyed
it as not done until after the scale had infested consid-
erable other nursery stock.
VARIETIES OF FRUITS INFESTED.
There are a great many varieties of fruits infested,
especially those belonging to the Rose family, (order
Rosacex). All varieties of pears, plums and peaches are
liable to be attacked, apples, cherries and quince
are also attacked, but as these are not grown for profit
in this State, they need not be considered further than
that they are hosts for these pests. We have reports also
of their occurring on English walnuts, European elm,
persimmon and rose bushes.
The Japanese plums (not loquats or medlars) are
most severely attacked; next to these are peaches. Apple
trees are often attacked severely, but these are so few and







It occurred several times, while I was inspecting
orchards at DeFuniak, that only one tree out of a hun-
dred was found to contain any insects at all, but the
presence of a single infested tree is as dangerous to an
orchard as a single case of cholera is to a community.
We have all reason to believe that the dissemina-
tion of diseased trees by nurserymen was entirely free of
any bad intention, and due to an ignorance of the pres-
ence of the scale. As soon as the presence of this pest
was discovered all efforts were made to stamp it out.
OCCURRENCES IN THE EAST.
So far the insect has been found, in the East, in the
following States: Missouri, Indiana, Ohio, Maryland,
New Jersey, New York, Pennsylvania, Virginia, and
Florida. New Jersey and Missouri seem to be largely
responsible for its dissemination in the East. They have
been traced directly from New Jersey to California. They
were brought to New Jersey on some Kelsey plum trees
in 1886 or 1887. While the original trees were destroyed
it as not done until after the scale had infested consid-
erable other nursery stock.
VARIETIES OF FRUITS INFESTED.
There are a great many varieties of fruits infested,
especially those belonging to the Rose family, (order
Rosacex). All varieties of pears, plums and peaches are
liable to be attacked, apples, cherries and quince
are also attacked, but as these are not grown for profit
in this State, they need not be considered further than
that they are hosts for these pests. We have reports also
of their occurring on English walnuts, European elm,
persimmon and rose bushes.
The Japanese plums (not loquats or medlars) are
most severely attacked; next to these are peaches. Apple
trees are often attacked severely, but these are so few and








so scattered in this district that they are not of much
economic importance. Of the pears the LeConte and
Keiffer varieties are least attacked. These varieties are
almost immune, but as they support the insect, an
infested LeConte or Keiffer tree must always be considered
a source of infection for less hardy varieties. Some
Bartletts are so deformed by the pest that they could
scarcely be recognized. Professor Smith finds that the
LeContes suffer more from the insect than the Keiffers in
New Jersey, while observations indicate that the reverse
is true here. In an orchard that is made up of plums
and LeContes the insects have nearly ruined the plums,
while the pears are apparently as vigorous as though no
scale were present. There are thirty-seven trees to the
row, and the two kinds are planted alongside of one
another. The orchard was cultivated regardless of
variety. Beyond the fourth row of pears, from the
plums it was difficult to find any scale.
Adjoining this orchard there was an orchard of sixty
trees obtained from a large Georgia nursery. In 1892 it
was noticed that this was diseased, in the fall of '94
three-fourths of the trees were dead, ten trees were still
healthy looking, but covered with scale, and the rest were
sickly.
REMEDIES.
The remedies used were those suggested by the Div.
of Entomology, U. S. D. A.; Kerosene Emulsion and Resin
Wash. Below are given formula and directions for pre-
paring these insecticides:

KEROSENE EMULSION.
Soap (hard or whale oil)............................ pound
W ater ..... ..... .... ... ............ 1 gallon
Kerosene............................ ...... 2 gallons







PREPARATION.
Dissolve a half pound of hard soap in a gallon of
boiling water. The soap will dissolve more quickly if it
is cut into small pieces, and the water, with the soap in it,
stirred while heating: The heating may be done in an
ordinary iron kettle. When the water is heated to boil-
ing and the soap all dissolved, the kettle may be removed
from the fire and the kerosene added, care being taken not
to ignite the kerosene. After the kerosene has been added
the mixture should be thoroughly churned for ten min-
utes. A good way is to force it through a spray pump
back into the kettle several times. Emulsion prepared
over a fire with the water near boiling kept two years
without separating entirely.
In making kerosene emulsion there are two points to
be kept in mind constantly. 1st. To keep the water and
kerosene just as hot as possible without igniting the kero-
sene. 2d. That during this time the material must be
thoroughly and vigorously agitated. Merely stirring with
a paddle will not do. Nor will it make emulsion by using
warm water. The nearer the igniting point of the kero-
sene and the harder the material is churned, the better
will be the emulsion.
The emulsion may be tested by placing a corked
bottle full of it in a cool place for twenty-four hours; if no
clear liquid rises to the top nor dark liquid settles to the
bottom, the emulsion may be considered good.
Some trouble has been reported from the use of hard
water; it is therefore recommended that rain water be
used in those districts that have hard water.
When ready to use take one part of the preparation
and nine of water; stir it until it is mixed evenly, and
apply.
This insecticide is recommended for insects that
obtain their food by piercing plants and sucking the








sap, as plant lice. It is also an excellent remedy for the
young scale before the wax has been secreted. This has
also proven an excellent wash to kill lice and other par-
asites on animals. Care must be taken, however, that no
free kerosene remains, as this will rise on the mixture and
coming in contact with some tender-skinned animals
might cause the hair to fall. When diluted with twelve
parts of water it has given excellent results in killing
lice on cattle. It is applied to the animal with a spray
or force pump.
RESIN WASH
is one recommended by the Division of Entomology,
United States Department of Agriculture, as a summer
wash for the San Jose scale.
Resin.................. .............. .............. 20 pounds
Caustic Soda (70.per cent strength)............. 5 pounds
Fish O il ................... .. ................... 3 pints
Water to make.................................. 100 gallons
PREPARATION.
Place the resin, soda and fish oil in a large kettle,
put in enough water to cover four or five inches deep;
then boil for an hour or an hour and a half, when the
liquid will be a dark, coffee-brown color. Water is
added gradually and the liquid stirred to keep it mixed
evenly.
RESIN WASH FOR WINTER.
Resin................. ........... ......... .. 30 pounds
Caustic Soda (70 per cent strength)............ 9 pounds
Fish Oil.............................. 4 pints

THE TWO REMEDIES COMPARED.
Both the Kerosene Emulsion and Resin Wash were
used in orchards at DeFuniak with good effects.
Resin Wash-At first the formula for summer Resin
Wash was used, but the strength was gradually increased








to that of the Winter Resin Wash. This killed all the
young scale and nearly all of the older ones, but a few of
the places on the trees were not touched and consequently
it failed to kill all insects. During the fall the insects
secrete themselves between the bud and the portion that
holds the leaf. These places form small pockets, or
recesses, that the insecticide does not enter, hence does
not cover them. Insects hidden in such places escape to
start new broods.
SPRAY THOROUGHLY.
In using either of the above insecticides it must be
remembered that only such insects are killed as are cov-
ered with the material, hence, any portion of the tree left
unsprayed may carry the disease over. This was very
noticeable this year; wherever last year's work had been
done thoroughly there were few insects to be found.
Some trees were tried as special tests, and com-
pletely covered with the wash, with a view of noticing
the effect on the tree; no live scale could be discovered by
a most dilligent search and the trees were not killed.
An orchard that was considered worthless last year,
when treated to a thorough spraying of Winter Resin
Wash was almost entirely free this year. However, it
did nearly as effective work on the flower buds for this
spring, nearly all of which were killed.

DON'T USE THE WINTER WASH IN WINTER.
The term "Winter Resin Wash" was given to this
formula because the trees in the Northern climates pass
through a long dormant state in winter, and are not
easily hurt in this condition. In such climates it was
found that the trees could stand a much stronger insecti-
cide during the winter. In our State the fall merges
into spring, and the trees do not take on the dormant
winter state. Very often the early peaches begin to








bloom in December, and continue to send forth a few
blossoms during warm spells until the spring bloom has
disappeared.
A very interesting fact was developed during the
work. Where the Winter Resin Wash was used later
than the first week of November it killed a great many
flower buds. The damage increased with the thorough-
ness of the spraying, and with the advance towards
spring. In some orchards where the application was
thorough and late (about February) practically all the
fruit buds were killed, but no other damage was percepti-
ble.
A very good illustration of the critical strength of
the Resin Wash occurred in a seven-acre orchard. In
the forenoon the usual winter wash was used, at noon
the strength was increased. The portion of the orchard
treated in the afternoon bore practically no fruit, and the
scale was also much less severe. The orchard was
sprayed about November 1.
KEROSENE EMULSION.
This substance was used about double strength on
several orchards, including the one on the DeFuniak
branch Experiment Station. Superintendent Stubbs had
this orchard treated about the last of October. The
insects were not severe on the premises. This year there
seemed to be even more than there were last year.
As this seems to be the usual verdict on the use of
Kerosene Emulsion we would not recommend it as the
most effective remedy. It has the advantage over Resin
Wash that it is not liable to injure the trees or fruit, and
that it can be used at any time during the summer. It
would probably have little value as a winter wash.
If used it will be necessary to repeat the spraying at
shorter intervals than in the case of the Resin Wash.









COMPARISON OF KEROSENE EMULSION AND RESIN WASH.
Cost of material for making 100 gallons Kerosene
Emulsion:
5 Pounds Hard Soap, at 3c............................... .15
20 Gallons Kerosene, at 18c............................ 3.60

$3.75
Cost of material for making 100 gallons Resin
Wash:
20 Pounds Resin, $1.80 per barrel.................... .18
5 Pound Caustic Soda, .6 ............................... 32
3 Pints Fish Oil, .60 per gallon....................... .222

.73
The formula for summer wash is used, because it is
as effective as the Kerosene Emulsion. The labor of
preparing is about the same for each. The Winter
Resin Wash, on the same basis, will cost $1.19- per hun-
dred gallons.
SPRAY DURING DRY SEASON.
Several orchards were sprayed just before heavy
rains. The result of the work .in such cases was far from
as satisfactory as in the cases where the spraying was fol-
lowed by dry weather. The reason for the less effective-
ness in the rainy season is that the insecticide, which
forms a coating over the insect to smother it, is washed
off before the insect is killed.

PERSISTENCY OF THE PEST.

It is certainly very difficult to eradicate the pest
when it has once established itself. While the spraying
solution may kill all it comes in contact with, it will be
found exceedingly difficult to reach every insect on the
tree. There will be very little trouble, however, to keep
the pest down, and to prevent its spreading to young









orchards, if one uses the spraying solutions at the proper
times and uses them thoroughly.
There are other insecticides and other methods that
might be used in combatting this insect, but as these
could not at the time be tested we cannot report on them.
The use of cyanide gas and tents is commended
where one has a small orchard. This method is said to
kill out the last remnant of the scale, but it is expensive
and tedious.
NATURAL ENEMIES.
The officers of the Division of Entomology, in the
Department of Agriculture, have discovered several insect
enemies of this serious pest. but as these parasites do so
little effective damage to the progress of their host, it is
not wise to depend on them.
During the spring Mr. G. H. Hallowell, President
West Florida Highland Fruit Growers' Association, found
an interesting and seemingly an effective enemy of this
scale. The find was reported to the DeFuniak Breeze.
Mr. Hallowell kindly sent us some specimens of these
parasites. Upon rearing them to maturity, they proved
to be our omnipresent friend, the twice stabbed lady-bird
(Chilocorus Birulner.s'). On July 26, the orchard was
visited and it was very evident that "No trust can be
safely placed in these natural enemies. A little active
work will benefit the farmer more than all the natural
Enemies can possibly advantage him in ten years to
come."
The following discussion of the Life History, and How
the Insect Spreads, has been taken from Bulletin 106 of
New Jersey Experiment Station, by Dr. J. B. Smith.








LIFE HISTORY.
"As the study of this insect is a matter of national
importance, it has been taken in hand by the Division
of Entomology of the United States Department of Agri-
culture. Indeed, the insect had been studied and its life
history ascertained in California years ago, so we are
quite familiar with its general habits and development.
I deemed it unnecessary to duplicate work and made no
attempt at original study. I have confined myself to
observing the development and habits of the insect in
our State, and to ascertaining those points that are prac-
tically important in its treatment. The life history that
follows is therefore taken, in its essential features, from
Circular No. 3, Second Series, of the United States
Department of Agriculture, Division of Entomology, sup-
plemented by my New Jersey observations. The illustra-
tions are also from the above mentioned circular, electro-
types being procured by the courtesy of the officers of the
Department.
"The San Jose scale belongs to the group of armored
insects, to which the common oyster-shell bark-louse of
the apple belongs. It differs from that species in that
the scale is perfectly round, or at most very slightly
elongated and irregular. In these particulars it resem-
bles the 'scurvy scale,' Chinnaspis furfurus, or 'Harris
louse,' as it seems to be quite universally called in this
State; but it is decidedly smaller and more convex than
the latter species. Its round shape and small size dis-
tinguish it at a glance from all the other species infesting
deciduous fruit trees in our State. It is quite flat, a lit-
tle raised in the center, pressed close to the tree around
the edges, resembles the bars of the twigs in color, and
when full grown is decidedly less than one-eighth of an
inch in diameter, perhaps the majority of the scales do
not equal one-sixteenth of an inch, where they are closely








crowded together; but where a few only are found on the
succulent shoots, or on fruit, they become larger, and the
females may, in extreme cases, reach nearly one-eighth
of an inch. The males rarely exceed one-sixteenth inch
in diameter. At or near the middle of each scale is a
small, round, slightly elongated black point; or this
point may sometimes appear yellowish.
When occurring upon the bark of twigs or leaves in
large numbers the scales lie close to each other, frequently
overlapping, and they are at such times difficult to dis-
tinquish without a magnifying glass. The general appear-
ance which they present is a grayish, very slightly rough-
ened, scurfy deposit. This is much more prominent on
the trees like the peach, or those varieties of apple and
pear that have a reddish color, and when these are thickly
infested they seem to be coated with dust or ashes. When
the scales are crushed by scraping, a yellowish, oily liquid
will appear, coming from the soft yellow insects beneath
the scales, and this will at once indicate to one who is not
familiar with their appearance the existence of healthy,
living insects beneath the scaly covering.
These are easely scraped off with the finger nail,
and the bark beneath them will be seen to be darker in
color, as will be seen by comparing the places from
which the scales have been removed with the spots upon
which the scales do not occur, while the circumference
beyond the scales frequently becomes changed in color
to a somewhat purplish or crimson shade. Where the
scales do not occur so thickly they are more perceptible,
and upon young, reddish twigs the contrast is quite
noticeable, as the scales there appear light gray. Younger
and smaller scales are darker in color than the older and
larger ones, and sometimes appear quite black, while, on
the other hand, those that are just set may be white or
yellowish.








During the winter the insect is to be found in the
half-grown or nearly full-grown condition, and as soon as
the trees resume activity in spring the insects resume
their feeding. In New Jersey they reach their full
growth during the latter part of May, and the young
begin to hatch and crawl from under the female scales
during the first week in June, and from this time through
the summer there is a constant succession of generations.
The first living larvae that I received reached me on
June 11th, having been gathered June 10th, and at that
time I found on the twigs a number of young scales that
had just set, indicating that active larve had been about
at least three or four days previously. Up to June 15th
every infested tree examined showed active young
larvae, and after that time there seemed to be a period of
about a week or ten days during which no larvae were
noticed. Early in July, however, young larvae were
again active and crawling about everywhere, and this
condition of affairs continued throughout the balance of
the summer extending through October, and even into
the first part of November until, in other words, the
trees had become quite dormant. The young louse is
an active, crawling creature, very minute and yellowish
in color. The young spread out upon the new growth
of the tree, settle down, and each begins to secrete a scale.
The male is an active two-winged insect, while the full-
grown female loses her legs and antennae, and bears a
very slight resemblance to a living creature.
"The insect affects not only the young twigs and
limbs, but covers as well the trunk to the surface of the
ground, and exists upon the leaves and upon the fruit.
When it is abundant the fruit is destroyed, or at least
rendered unfit for market. One of the most character-
istic points in the appearance of the insect upon fruit
is the purple discoloration around the edge of each scale,








So far as we know, this result is confined to this species
alone. Upon the leaves the insects have a tendency to
collect along the midrib on the upper side of the leaf in
one or more quite regular rows, and also to some extent
along the side ribs. The infested leaves turn brown, but
do not have a tendency to fall as a result of the damage.
There are two points of interest and importance to
be noted in this life history. The first is, that the insect
passes the winter beneath the scales in a partly grown
condition. Usually they are about half grown, but some
will be younger, and some will be older. They seem to
continue reproduction until the tree is entirely dormant
and no further food is obtainable. On the other hand,
they do not seem to renew growth very early in the
spring, but are slow to begin reproduction; no larvae
having been noted until June, as has been already stated.
The second point is, that once they begin there is prac-
tically no period during the summer at which the young,
active, crawling lice are not to be found upon the tree.
The length of time during which a given female will
continue to reproduce has not been ascertained, but it
seems likely from what has been observed that breeding
continues for quite a long time, and that the female
scales that have lived during the winter may continue to
live on and reproduce during the greatest portion of the
summer, when their daughters and grand-daughters are
already full grown, with nearly full-grown progeny.
There may be, therefore, upon a plant at one time, young
born of as many as three, or even four distinct genera-
tions. As nearly as I have been able to ascertain, from
my observations during the present season, a little less
than a month is required to bring an insect to maturity.
That is a larva hatched today will be ready one month
hence to bring forth living young in turn, and this will
allow at least four, if not five, distinct broods during the
Summer and fall."








HOW THE INSECT SPREADS.
It has been stated that the full-grown male of this
insect is winged. It is very minute, scarcely noticeable
without a lens, very light and frail, at the mercy of the
least puff of wind, and incapable of any great journey.
The female has no perceptible legs, and is utterly incapa-
ble of motion. She resembles a yellowish, or orange, flat-
tened seed, in bulk many times that of the male, but
firmly fixed to one point by the scaly covering, which is
at once her protection and her grave. The young are
active for a very brief time, two or three days at most,
and they crawl with considerable rapidity and great per-
sistence, so that they might possibly descend from one
tree and crawl for a number of yards to another; but the
spread in this manner is insignificant. Where trees are
close together they mayjpass from the branch of one tree
to another; but I have found that they rarely crawl long
in any one direction; they rather move around, rapidly
enough, yet irregularly and at random. Usually they
do not go farther than is necessary to find a good place
to fix, and at once begin to form a scale. This process
is rather interesting and can be watched. As soon as the
young louse has inserted its beak into the plant, and has
begun to feed, a change comes over it, and within a few
hours it is entirely covered with a fine, white, waxy film.
This turns first yellow, and then gray, or even black, and
the creature is a fixture, absolutely incapable thereafter
of shifting its location under any possible circumstances.
Strong winds may carry the young bodily from one tree
to another; but the principal method of spread is by
means of other insects which are winged, and by birds.
The active young lice will soon crawl upon any small
winged insect, particularly if the latter is of a dark color,
and they may be carried by it to considerable distances.
They also crawl upon the feet of birds which visit the








trees, and may thus be carried for miles. They are often
found upon ants, and ants, as everyone knows, are great
travelers. This difficulty in moving from one place to
another, and the dependence upon external agency for
their distribution, will account for the fact that trees here
and there in an orchard newly set out may be very badly
infested, while not a trace will be seen on the trees on
either side. Few birds or insects visit a young orchard
that is at all well kept, and the distance between the
trees, especially if the land is cultivated, is altogether too
great to be covered by the young lice, even did they
know enough to make a bee-line for the nearest point.
The result is that nearly every young scale fixes upon
the tree on which it was hatched, killing it more rapidly
than would otherwise be the case; but at all events con-
fining and preventing spread to points not theretofore
infested. This also explains why nursery stock is so
evenly troubled: here the trees are grown just as closely
together as is possible in rows, and there is no hindrance
to crawling from one to the other.
"As the insects must feed for a time in spring before
attaining their full growth, it follows that only such as
are fixed to the tree itself have any chance of reproduc-
ing their kind. Those that fix to the leaves fall with
them, and as they dry or decay the insect dies for want
of food before attaining maturity."
A PRACTICAL ILLUSTRATION
of how the insect spreads was afforded in Florida.
Growing in an infested orchard were some melons which
were kindly offered to a friend about three miles away,
who took some from the orchard in a wagon to his home.
A year later scale developed on the place that was free
before. The first appearance was on a tree under which
the team had been hitched while the melons were taken
to the kitchen.









The case is clear enough; the team and wagon driven
into the infested orchard became the means of carrying
the insect through a distance of three miles. No doubt
these were the young crawling scale that had restlessly
wandered onto the harness or wagon, and then crawled
off again when the opportunity afforded escape.
('CAUTION.
It is strongly urged upon all dealers of fruit trees in
this State, and in other States as well, to be exceedingly
careful in disseminating fruit trees grown by some one else.
After this all stock will be regarded as suspicious by our
fruit growers. It is exceedingly damaging to have the
unenviable reputation of sending out diseased stock. The
Experiment Station reports on specimens sent for exami-
nation. It is not known for what purpose the informa-
tion is desired, and, in the majority of cases, the enquirer
is not known.
One case came under my observation where the
nurseryman seems entirely innocent of intention at fraud,
and ignorant of the fact; possibly he handled a few trees
from another nursery.
SENT) IN SPECIMENS.
All persons are urged to send specimens of suspi-
cious looking twigs to the experiment station for exami-
nation. In the beginning the insect can be stamped out
with comparatively small loss.
RECOMMENDATIONS.
1. If the San Jose scale is on a lot of trees just
received from a nursery, burn them immediately, wrap-
ping, box and all.
2. If the trees have been set out you will do wisely
if you destroy them, and do not plant the place to trees
subject to this disease for a year.
3. If there is only here and there a bearing tree








badly affected, it will be cheaper to grub it out and burn
it on the spot.
4. If the orchard is generally affected, spray with
resin wash or kerosene emulsion during the dry season.
Repeat the spraying about every ten days or two weeks.
5. Do not use the winter wash later than the first of
November in this latitude; it is liable to kill the flower
buds.
6. We recommend that all stock received in quantity
be thoroughly fumigated in the original package. For
this purpose use potassium cyanide, 1 oz., sulphuric acid,
1 oz., water, 2 oz., for a box 4x4x6 feet; for other sizes
use same proportions. Put the water in a saucer or sim-
ilar dish, add the acid, then the cyanide. Close package
up quickly and be sure not to breathe any of the fumes;
it is a deadly poison. Keep the package closed for twenty-
four hours.
7. If a young orchard is to be planted in an infested
district, be sure to have a strip of woodland left between
the new and the old orchards. Be careful also not to
carry implements from the old orchard to the young.
By exercising dilligent care the insect may be confined
to the old orchard.
CONCLUSION.
The San Jose scale is an exceedingly pr,'i~riiOus
insect; it can be controlled by spraying with resin wash
or kerosene emulsion. The remedy is practicable and
profitable; this was demonstrated in an orchard of twenty
acres. The insect, when thoroughly established, can be
be exterminated by the use of these sprays only with great
difficulty if at all.
The spraying should be repeated; one spraying is
good, but two are better.




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