Title Page
 Board of trustees and station...
 Table of Contents

Title: Some common Florida scales
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00005162/00001
 Material Information
Title: Some common Florida scales
Alternate Title: Bulletin 51 ; Florida Agricultural Experiment Station
Physical Description: Book
Language: English
Creator: Gossard, H. A.
Publisher: Florida Agricultural Experiment Station
Manufacturer: H. & W. B. Drew Company
Publication Date: 1900
Copyright Date: 1900
 Record Information
Bibliographic ID: UF00005162
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aaa6480 - LTQF
aen1427 - LTUF
18155337 - OCLC
000920987 - AlephBibNum


This item has the following downloads:

Binder1 ( PDF )

Table of Contents
    Title Page
        Title Page
    Board of trustees and station staff
        Page 106
    Table of Contents
        Page 107
        Page 108
        Page 109
        Page 110
        Page 111
        Page 112
        Page 113
        Page 114
        Page 115
        Page 116
        Page 117
        Page 118
        Page 119
        Page 120
        Page 121
        Page 122
        Page 123
        Page 124
        Page 125
        Page 126
        Page 127
        Page 128
Full Text



Agricultural Experiment


Some Common

Florida Scales.



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, Florida.

1 0 ..

F~ ~ tfB t'^* *-^^

JANUARY, 1900.


HON. GEO. W. WILSON ........................Jacksonville
HoN. J. D. CALLAWAY ...................... ... Lake City
HON. L. HARRISON ............................ Lake City
HON. F. E. HARRIS.................................Ocala
HON. J. R. PARROTT ................... ....... Jacksonville
HON. E. D. BEGGS.................... ......... Pensacola
HON. C. A. CARSON. .......................... Kissimmee


W. F. YOCUM, A. M., D. D ................ ....... Director
H. E. STOCKBRIDGE, Ph. D........ ........ Agriculturist
H. K. MILLER, M. SC ................ ............ Chemist
H. A. GOSSARD, M. Sc.... ............. ...Entomologist
H. H. HUME, B. Agr............ Botanist and Horticulturist
W. P. JERNIGAN .......... .........Auditor and Book-keeper
JOHN F. MITCHELL .............. Foreman of Station Farm
JOHN H. JEFFRIES... Gardener in Horticultural Department
LUCIA MCCULLOCH .............. ............... Librarian
MINNIE HELVESTON ....... .............. ... Stenographer


Introduction ................... ......... ........... 108
The Purple Scale, Mytilaspis citricola ................ 108
The Long Scale, Mytilaspis gloverii ................... 112
The Turtle-back Scale, Lecanium hesperidum .......... 113
The Black Scale, Lecanium olece. ...................... 115
The Hemispherical Scale, Lecanium hemisphoericum. .... 116
The Wax or White Scale, Ceroplastesffloridensis...... 117
The Barnacle Scale, Ceroplastes cirripediformis ....... 119
The MealyBug, Dactylopius citri .......... ........ 120
General Observations Upon Spraying ............. 123
Sprays and Washes. ................................ 127



The frequency with which specimens of the following
scales are received at the Experiment Station, with inqui-
ries regarding their life histories and remedial measures
against them, furnishes the occasion for this brief bulletin,
While the principal plants upon which they have been re-
ported, namely, citrus and pineapples, occupy but a com-
paratively small acreage in Florida at present, the many
difficulties attending their successful production apparently
stimulates careful observation on the part of the producers,
and we, therefore, have had a greater number of queries
relating to these scales than to any other insects in the
The observations set forth are, for the most part, given
upon the authority of others, particularly of Hubbard and
Comstock, the particular excuse for publishing.what only
pretends to be, in a large measure, a review of their writings
being found in the fact that their papers are not accessible
to the Florida growers.
However, the writer is alone responsible for the eco-
nomic observations, and for the statement of facts not found
elsewhere. The lists of food plants given in Coccidae Amer-
canse, prepared by Professors Rolfs and Quaintance, have
been consulted, but their complete lists have not been given
in every case.
THE PURPLE SCALE, Mytilaspis citricola (Packard).
This is one of the commonest and most conspicuous
citrus scales in Florida. The insect seems to be widely
known wherever the orange is grown, either in this coun-

try or abroad. Hubbard observed in 1885 that it was more
abundant in the northern than in the southern portions of
the orange belt. The freezes since that time seem to have
reversed this order of distribution; this season's observations
have not discovered it in any of the northern nurseries, nor
in the more northern groves.
The scale of this species is one of the largest in the
genus. The scale of mature females sometimes reaches a

S citricola (Costock, Div. of Entomology, U. S. Dept. of
Agr., Ann. Report, 1880).-i. Scales on orange, natural size; la, scale of
female, dorsal view, enlarged; lb, scale of female with ventral scale and
eggs, enlarged; 1c, scale of male enlarged.
length of 0.12 of an inch (2 mm.), and that of the male 0.05
of an inch (1.4 mm.). The name, "Oyster Shell Bark-louse,"
has been applied to one member of the genus, Mytilapsis
pomorum, a common apple pest, because the general outline
of the scale, together with its ridgings and markings, are so
suggestive of an oyster shell in miniature; the purple scale,
of an inch (1.4 mm.). The name, "Oyster Shell Bark-louse,"
has been applied to one member of the genus, Mytilapsis
pomorum, a common apple pest, because the general outline
of the scale, together with its ridgings and markings, are'so
suggestive of an oyster shell in miniature; the purple scale,

Mytilaspis citricola, and in lesser degree, the long scale,
Mytilaspis gloverii, share this resemblance, and so it is not
uncommon to hear the term, "Oyster Shell Bark-louse," ap-
plied to any one of them by the general public. The form
may be described as broadly trumpet-shaped, increasing in
width behind, often curved like an oyster shell, but rarely
or never with the sides parallel. The surface is glossy and
smooth and from a light to a dark red-brown purple color.
The male scales being less than half the length of the fe-
males, of a more linear shape and straight outline, may
suggest some other species of insect upon superficial exami-
nation, but its identity cannot be confused with any other
species than the long scale, Mytilaspis gloverii, the female
of which is twice as long as the male citricola, and the
male of which is shorter and rather more slender, both ab-
solutely and relatively. The characteristic purple color
which the males give to a mass of scales belongs to no
other species of Mytilaspis.
The eggs are pearly white, very minute, elongate oval,
and are usually laid in four rows, but sometimes promiscu-
ously. Each female deposits from 25 to 70 eggs.
The newly hatched larva is irregularly oval in shape,
0.12 of an inch long, of a transparent white color, and with
fiery red eyes, which have been likened to grains of cayenne
pepper. This young insect wanders about a very short
time, and then settles upon the bark or leaves; when upon
the latter, preferably along the midrib, and is soon covered
with a white film of wax threads, some of which stand out
from the rest, and if not carried away by the wind, they
accumulate and form cottony tufts or tangles.
The shedding of the larva skin or first moult occurs
about three weeks after hatching, and the formation of the
true scale is begun. A second moult of the female occurs
three or four weeks later, and when nine or ten weeks old
egg-laying begins, the eggs being deposited beneath the
scale, from beneath which the young begin to issue in about
a week after the eggs are deposited, unless retarded by cold

The male goes through its second moult and changes
into a pupa several days earlier than the female, from which
it emerges as a winged fly. and is ready for mating at the
time the females are passing through their first moults.
There are three or four generations per year, but the
separation into distinct broods is often more or less con-
fused, one generation overlapping the succeeding one, so
that all stages of the insect may generally be found at al-
most any season of the year upon infested trees. Generally
speaking, the greatest numbers of migrating young may be
found in one of three periods, namely: in the spring usually
in March and sometimes extending into April: in June or
July, and in September or October. During mild winters a
fourth brood commences in January and straggles through
this and the following month.
The recorded food plants of the insect are as follows:
Banksia integrifolia, Croton. Eucalyptus. Murraya Ex-
otica, Orange and Ptelea trifoliata.
Natural Enemies.-Several minute hymenopterous par-
asites attack this scale, leaving the evidence of their work
in the shape of minute circular holes in the backs of the
scales, through which the small wasp-like flies have eaten
their way after having destroyed. while undeveloped slugs
or larval, the enclosed scale insects and their eggs. Various
species of lady-bugs feed upon this and other scales in all
stages of development, raising the scale and devouring both
the mother insect and the eggs when young migrating
scales or other food is not more convenient.
The "trash bugs" or larvm of the lace-wing flies also
devour many. These curious creatures may be recognized
at once by the flocculent masses of grayish trash which
they carry about on their backs as a means of protection.
Similar insects, belonging in a different genus, Hemero-
bius, still lace-wings, but without the trash mask in the
larval stage, are almost equally effective.
Remedies.-Kerosene emulsion, resin wash or whale oil
soap. See section on remedies in latter part of bulletin.

THE LONG SCALE, Mytilaspis gloverii (Packard).
The long scale is of a more linear shape than the purple
scale, with which it is often associated. The outline of the
body is not so often curved as is that of the purple scale.
The Female.-The female scale is brownish, about 0.11
of an inch (3 mm.) in length, and less than one-fourth as
wide. When crowded the scales adjust themselves to their
surroundings by taking all sorts of shapes, and many will
be dwarfed and malformed almost beyond recognition, ex-

. \ 4 i\

r .^ *i- ir

i .. *.

I6arx di.

Fig. 2.
Mytilaspis gloverii (Comstock, Div. of Entomology, U. S. Dept. of
Agr., Ann. Report, 1880).-2. Scales on orange, natural size; 2a, scale of
female, dorsal view, enlarged; 2b, scale of male, enlarged; 2c, scale of
female with ventral scale and eggs, enlarged.
cept by microscopic examination. The young insects them-
selves are of a translucent waxy white, with the outer edge
of the last joint yellowish. As they grow older, they in-
cline to purple, which becomes deeper as the insects in-

crease in age. The adult female is about 0.05 of an inch
(1.3 mm.) in length. The sucking proboscis is longer than
the body.
The iMale.-The scale of the male is smaller than that
of the female, about 0.04 of an inch (1 mm.) in length, and
usually straight. The color varies from shades of brown to
yellow when young, becoming darker with age, and reach-
ing a dark brown in the older females. Generally speak-
ing, densely clustered colonies, including both sexes, have
a reddish hue. The male insect is a minute, two-winged
fly, 0.01 of an inch in length. Its body is pale pink in color,
and about one-fourth as wide as long. The eggs are elon-
gate-oval in shape, passing from a light to a purple color
before hatching.
Life History.-The life history of this scale is so nearly
parallel with that of the purple scale that it is unnecessary
to enter into details. It has practically the same number of
broods, which occur at about the same time as those of the
other species. Sometimes the broods of the one species pre-
cede or follow those of the other by a few days. but they are
often simultaneous. The times of applying remedies, there-
fore: can be stated to be parallel with those chosen for the
purple scale. The parasites of the two species are. likewise,
the same.
Remedies.-Same as for preceding species.

THE TURTLE-BACK SCALE, Lecanitiu hesperidlm (Linn).
The turtle-back scale, with the others described in the
following pages, belong to a sub-family of naked or waxy
scales, known as Lecanae, and are not covered with a true
scale. The genus of Lecan iums are unprotected by any
covering, except their skins, which become toughened with
age so as to resemble parchment.
Description.-The full grown insect is from 1.12 to 1.16
of an inch (3 to 4 mm.) long, broadly oval, more or less
swollen and convex upon the disk, surrounded by a thin,
flat margin, which is notched on the sides and behind;

this shape, with the brownish color, gives it its popular
name. The legs are concealed beneath the body.
Life History.-The
young insect is of a yellow-
ish color, and always settles
flupon the bark and leaves of
tender growth. The adult
insects appear to be unable
S'' to pierce the bark of the
trunk or older branches,
always being found upon
wood of newest growth.
9 *' In the spring and early
summer, when new growth
'' is forming, the increase of
'' ''' the insect is most rapid,
v' / especially during the month
.I of June. Later in the sea-
S son the colonies disappear,
/' only a few gravid females
I remaining to restock the
Plants at the next favorable
.opportunity. The young,
hatching in the latter part
JfI of the season, often starve,

Fig. 3.
Lecanium hesperidium, (Comstock, Div. of Entomology, U. S. Dept.
of Agr., Ann. Report, 1880 -Adult females on orange, natural size.

because they are unable to reach tender twigs upon which
to feed.
Parasites.--This scale, being unarmored, is particularly
subject to attacks of the wasp-like chalcids, a number of
which attack it freely. The parasitized insects can be rec-
ognized by their bloated bodies, more or less suggestive of
miniature inflated balloons. By mid-summer the parasites
are usually present in such numbers that the insect would

be reduced below the possibility of inflicting much damage,
even if its feeding habits did not restrict it.
Among the more important food plants of this insect
are the maple, Camellia japonica, fig, grape, holly, laurel,
orange, palms, peach, poplar, plum, rose and willow.
Remedies.-Resin wash, kerosene emulsion or whale oil
THE BLACK SCALE, Lecanium olece (Bernard).
This scale is very similar to the preceding species,

Fig. 4.
Lecanimui ole:c (Comstock, Div. of Entomology, U. S. Depart. of Agr.,
Ann. Report, 1880).-Adult females on olive, natural size; a, female en-
nearly black in color, approaching hemispherical in form,
and longer than broad. Length from 0.16 to 0.20 of an inch

(4 to 5 mm.), height about 0.12 of an inch (3 mm.). The
middle of the back carries an elevated keel, which is crossed
at right angles by two elevated ridges, the latter dividing
the body into nearly three equal parts. The body is slightly
margined, the outer part of the disk being marked with
many small ridges, which extend from the margin half way
up to the centre of the back.
Egg.-Long, oval in shape, about 0.12 of an inch in
length, and of a yellowish color.
Life History.-The young larvae prefer the smaller
twigs of the plants which they infest, and usually settle
upon the leaves. The development of the species is slow,
so there is probably not more than one brood per year. It
lives upon all citrus plants, olive, pear, apricot, plum, pom-
egranate, apple, eucalyptus, rose, cape jessamine, live oak,
holly, oleander and some other plants.
Parasites.-The species is preyed upon by parasites be-
longing in the family of chalcidce mentioned in connection
with the preceding species, the same parasites probably
feeding more or less indiscriminately upon all the Lecani-
ums. Some predaceous caterpillars, such as Lcetilia cocco-
divora and others belonging to the family Tineidae, also
feed upon them, eating out the eggs and young larvae before
they have escaped from beneath the scale. Mites also con-
sume the eggs and young. The different species of lady-
bugs feed upon them freely.
Remedies.-Mild applications of kerosene emulsion,
resin wash or whale oil soap used as sprays.

THE HEMISPHERICAL SCALE. Lecani m h emiisph wrc, m
This scale is of a more rounded form than the other
common species of Lecanium, approaching the form of a
hemisphere; about 0.14 of an inch (3.5 mm.) in length, 0.12
of an inch (3 mm.) in width, 0.08 of an inch (2 mm.) in
height. The color varies from a light, almost reddish
brown, when young, to a dark brown, slightly tinged with

red when old. The insects found upon twigs are usually
more elongate than those found upon leaves.
Egg.-The egg is of an ellipsoidal shape, about 0.006 of
an inch (0.15 mm.) in length, and of a whitish color, inclin-
ing to yellow.
It feeds upon orange, palms, orchids, Camellia japoni-
cas, guavas, chrysanthemums and quite a number of other
The parasites are probably identical with those that
feed upon the preceding species, and the same remedies
would be found effective.

THE WAX OR WHITE SCALE. Ceroplastesjl,,, ,,! ..
This beautiful insect is U.0 to 0.12 of an inch (2 to 3
mm.) in length, of an oval form. convex above, and concave
beneath. The upper surface presents a rounded protuber-
ence in the centre, around which are arranged six or eight
smaller prominences or lobes, which are separated by a
groove from the central projection. The white covering
consists of soft wax, quite similar to the commercial article.
The color in clean specimens inclines to a beautiful flesh-
tinted white, the pinkish tinge being given by the reflection
of the light through the wax from the red insect beneath.
The insect itself bears on its upper surface six tubercles,
three on each side, and shows a short anal tube, the end of
which is seen projecting from the posterior or extremity of
the waxy covering at the bottom of a deep pit. The walls of
the body are very thiri, and enclose liquids or eggs of a dark
red color. The egg is 0.01 of an inch (0.25 mm.) long, and
of ellipsoidal form.
Life History.-The eggs. 75 or 100 in number, are ex-
truded from the body and hatched beneath the waxy scale.
The young, escaping from beneath the scale, attach them-
selves by their beaks to the surfaces of the leaves, chiefly
along the midribs and veins. As they approach maturity
they go to the bark of the twigs and smaller branches. The

exudations of wax first form in ridges, the marginal ones
uniting around the central one.
About a dozen or fifteen similar tufts of wax arise
around the centre, and the young louse, when about a week

7 '
', /i '" >t \

size; 2e, young female, enlarged; 25, adult female enlarged.
.J. Ceroplastes cirripediformnis.-Adult females, natural size; 3a, fe-
male, enlarged.

old, has been compared to an oval white star upon the leaf.
At this stage it has some superficial resemblance to some of

the stages of insects belonging in the Aleyrodide. The
adult insect is covered with six large plates, three upon
each side and three smaller plates located, one at each end
and one in the centre. The wax finally becomes covered
with dust and dirt, giving it an appearance quite different
from that possessed when its development was just com-
There are about three broods, each extending over three
or four months. The first brood occurs in April and May,
the second in July and August, and the third in October
and November. This insect is restricted to Florida. and is
very commonly found upon gallberry in great numbers. It
also occurs upon quince, apple, pear, the citrus fruits, ferns,
figs, myrtles, guavas and a number of other plants. As the
insects become aged many of them fall to the ground and
perish, being unable to reascend the plants from which they
fell. The insect does not often become numerous upon
orchard or grove trees, but sometimes gets thick enough to
cause some alarm.
Parasites.-This insect, like the Lecanium, is subject
to attack, some of the parasitic species previously men-
tioned also feeding upon this scale.
Remedies.-It is not often that the wax scales require
particular attention, but we have some reports indicating
that they may inflict considerable damage during a short
period. If fully developed they will probably lose their
hold and fall to the groung in a short time, so are not
worthy of much attention while in this stage. When the
growing larve become numerous they can probably be best
checked by an application of resin wash; the wax coating
would, perhaps, furnish protection in some degree against
kerosene applications or whale oil soap.

THE BARNACLE SCALE, Ceroplastes cirripediformis
This insect agrees with the preceding species in
possessing a white waxy covering, but is differently marked.

The average length is 0.20 of an inch (5 mm.); width, 0.16
of an inch (4 mm.), and height, 0.16 of an inch (4 mm.).
The naked insect is dark reddish brown in color, of sub-
globular shape, and with a strong spine-like projection at
the posterior end of the body. The general white color is
often mottled with shades of grayish or light brown, the
boundary lines of the plates remaining apparent, even at an
advanced age. The back is covered by a convex dorsal
plate, which is met on each side by six lateral ones, each of
which is marked by a radiating nucleus in the centre. The
posterior plate is larger than the others, possessing two
nuclei, thus indicating that two plates are joined together.
The eggs are 0.014 of an inch (0.35 mm.) in length, and of a
light reddish brown color.
Life History.-The newly hatched larva are dark
brown in color, and follow practically the same course of
development as Ceroplastes yj., .. ',. ., .
It feeds on orange, quince, Eyipatorium and probably
upon a number of the same food plants as C. fl'1,,/.i,1 ',
but the species is much more rare than the white scale.
Remedies.-Same as for the preceding species.

THE MEALY BUG, Dactylopius citri (Risso).
This insect, with other closely allied species, is very
common in Florida. The adult female is from about 0.14 to
0.16 of an inch (3.5 mm. to 4 mm.) in length, 0.08 of an inch
in width, and very flat. The color is dull brownish yellow,
the legs and antenna agreeing with the body in color.
There are 17 appendages on each side, and most parts of
the body are more or less powdered with particles lighter
than the ground color. The egg is about .01 of an inch in
length, of long ellipsoidal form, and light yellow color.
The two-winged male is about 0.033 of an inch (0.87 mm.)
in length, and has a wing expanse of 0.1 of an inch (2.5 mm.).
It is of a light olive brown color, with reddish attenne and
dark red eyes.
Life History.-The eggs are laid in a large cottony
mass at the posterior extremity of the abdomen, and require

considerable time to hatch. After hatching, the larvae ex-
hibit a marked tendency to settle along the midribs and
veins on the under side of the leaves or upon the younger
twigs, especially in the forks. When upon pineapples, it
seeks the bases of the leaves, often descending a short dis-
tance beneath the surface of the ground. This habit makes
it difficult to exterminate upon these plants.
It feeds upon house plants. orange. coffee, tobacco, cro-
ton, Ipomea, Learii, Habrothamnus. Peonia, Solanum
jasmoides and probably a number of others.

Figs. 7 and 8.
Dact!ilopivs citri.-Female and winged male. (After Comstock, Div.
of Entomology. U. S. Dept. of Agr., Ann. Report, 1880).
Natural Enemies.-This insect is especially subject to
attack by the chalcid flies and such predaceous caterpillars
as Letilia coccodivora. Lady-bugs also feed upon the
eggs and young.
Remedies.-The principal difficulty in handling mealy
bugs is not in killing them when they can be reached, but

in reaching them with insecticidal applications when upon
such plants as pineapple. Upon orange and plants above
ground they can be readily killed by kerosene emulsion,
resin wash, whale oil soap, decoctions of tobacco and salty
solutions. When upon pineapples, and it is wished to kill
the bugs without injury to the plants, perhaps an applica-
tion of kainit dissolved in water, one ounce in a quart, can
be used quite freely about the bases of the plants without
much danger of injury, if not used too frequently. A to-
bacco decoction, one pound in a gallon of water, is very
useful, and would not be dangerous to the plant under any
circumstances. Pyrethrum powder, used at the rate of one
ounce in two quarts of water, and thrown in the infested
parts of the plant with an atomizer, could also be adopted
with good results in some instances. Frequent applications
of mild insecticides are apt -to prove more satisfactory, in
this instance, than single severe treatments.


In discussing the question of artificial remedies, it may
as well be said at the outset that the determination of the
advisability of using them depends largely upon the partic-
ular circumstances belonging to each individual case: and
these circumstances can only become known as the result
of observation and experience, the larger and wider the
better. When available. the agencies employed by nature
herself are always to be preferred before artificial help.
Vigorous, healthy trees are seldom overrun by scales or in-
sect enemies, and if trees are seriously attacked, it can gen-
erally be taken as an indication that they are diseased in
some part, and that their strength and resisting powers are
depleted. The reasons for such weakness may be due to
physiological causes, to lack of proper fertilization, or to
other and more obscure factors. If the exciting cause of
the trouble can be discovered, of course the natural remedy
consists in removing it by appropriately modifying the
course of treatment and cultivation to which the tree has
been accustomed, by supplying the fertilizing element
which it lacks, or by doing whatever else may seem to
promise well in the premises. An application of fertilizer
sometimes proves an efficient corrective, but, on the other
hand, it may, if used too freely, over-stimulate the plant,
and later cause a reaction, which entails greater damage
than the first trouble.
Trees that are properly pruned, and in which the small
and shaded growth in the interior of the top is cut away,
are not so apt to be attacked as those which are left to
themselves. Shaded branches, like shaded plants, being
unable to perform assimilative processes perfectly, are, by
the enfeebled conditions thereby entailed, apt to become

harboring places, from which armies of scales will sally
forth whenever the physiological condition of the tree is for
any reason deranged. For similar reasons, groves in which
the trees are adequately spaced are more immune than
those in which they are crowded. It is almost impossible
to lay too much stress upon the necessity for free circula-
tion of air and the admission of sunlight.
Observation of the numbers of natural enemies at work,
coupled with the conditions and surroundings, as above dis-
cussed, will often give a clear indication to the experienced
grower as to the advisability of using insecticidal washes.
We do not believe that insecticidal sprays are used to
nearly the extent which their usefulness warrants, but, on
the other hand, there seems to be a pretty well founded
opinion that many who do spray are apt to overdo the
good work, especially in the first enthusiasm which marks
their introduction of the new process, and before experience
has taught them that there is a danger line in "much spray-
ing," as well as in multiplied numbers of bugs. Many men,
who have suffered from such an experience, have become
settled sceptics upon the whole subject of spraying, and are
distrustful of any measures of this character; others have
suffered in the same manner from no assignable cause, the
sprays having been applied as moderately and intelligently
as was possible in our present state of knowledge, and these
men have naturally joined the contingent who condemn
the practice. Some of these detractors allow nature to take
her course without further attention, sometimes, and gen-
erally, paying a greater or smaller price for their negli-
gence, sometimes happily finding, or rather being found, by
a stroke of good luck exceeding any reasonable expecta-
tion. Other and more persistent men, having abandoned
hope of relief through the spray pump, are led to study and
apply the natural agencies, which have been briefly dis-
cussed in the preceding pages with such intelligence and
success that it is admitted that they have little or no neces-
sity for using sprays. These latter men, being artists in
their profession, give a weight with many people to the

idea of "no spraying at all" that does not seem to us to be
warranted by either the facts of common observation or the
general experience of the past twenty years. While we
freely concede that some groves are in more danger from
the pump than from the insects that swarm over and
through them, and, again, that under ordinary circum-
stances it is within the limits of possibility tq so guide the
forces of nature as to render the application of sprays
largely unnecessary. it should not be forgotten that be-
tween these two extremes of practice is included that great
body of growers who will not risk the threatened sacrifice
of their annual crops. and. perhaps, of their orchards as
well, to the folly of inertia on the one hand. and who have
not had the experience nor. perhaps, the occasion, on the
other hand, to acquire that knowledge of natural agencies
sufficient to enable them to master an emergency which
may have overtaken them suddenly: and since the great
reliance of the successful non-sprayer consists, in the main.
of prevention and not cure. his knowledge is of not great
avail to the man who either has not taken the precaution-
ary preventive measures, or whose efforts in such direction
have failed for some reason, good or bad. It may be further
observed in this connection that. perhaps. there is no man,
however careful and foresighted, that would not find it to
his advantage to use sprays at times. We do not believe it
is possible for any man, under all circumstances, to success-
fully suppress or avert such an insect as the San Jose scale
without resorting to spraying or fumigation, admitting that
it sometimes practically disappears, without the orchard-
ist's assistance, from infested orchards in Florida and ad-
joining States which possess a warm atmosphere of more
than ordinary humidity, and, hence. favorable to the devel-
ment of fungus growths.
We have discussed this topic of spraying at some
length, because, for some reason, it appears that many
Florida growers express themselves in an unusually con-
servative manner regarding the use of sprays.
Assuming, then, that more or less spraying will be

done, and is necessary, we will consider briefly the best
ways of applying them, and the materials which should be
We have known some orange growers who made a reg-
ular practice of spraying the trunks, larger limbs and inte-
rior shoots of their trees every one or two years with a mild
insecticide, such as whale oil soap, used at the rate of one
pound in from three to six gallons of water, and reported
that they found such application, if correctly timed, suffi-
cient to keep their groves practically clean. Of course,
such groves were not badly infested to begin with, or
stronger applications would have been needed. Others fol-
low the plan of watching for particular trees that are af-
fected to a greater degree than the rest, and of confining
their operations to these trees, not giving any application
at all to trees not in seeming need of treatment. It would
seem to us that the latter is the more desirable policy,
though either one might be better than never spraying at
all under any circumstances. We may remark here that it
is seldom that a tree needs applications oftener than once in
two years if the treatments are correctly timed; except for
special reasons even the San Jose scale, in orchards, does not
often need more than a biennial course of treatment, and it
may be laid down, as a general principle, that a number of
mild applications judiciously following each other give more
satisfactory results, from the standpoint of both bugs and
plants, than single severe treatments.


Kerosene.-Perhaps no substance has a wider range of
usefelness than the preparations of kerosene in the form of
emulsions, mechanical mixtures, and soaps. No one insecti-
cide has been so generally used, and with such satisfactory
results, as the standard kerosene emulsion in use for so
many years. This has proven especially true on the Atlan-
tic coast and in humid countries. While mechanical mix-
tures of kerosene have the advantage of being readily used.
and, perhaps, are more penetrating for insects like the ar-
mored scales, they have not been extensively used in Flor-
ida for the particular insects described in this bulletin, and
until they shall have been more widely tried, we are unable
to pass positive judgment as to their desirability as com-
pared with the emulsion. Of the insects herein treated, the
emulsion may be recommended for the two species of Myti-
laspis, for the Lecaniums, the mealy bugs and the wax
scales before the waxy covering entirely shields the body.
Resin IWash.-After the kerosene preparations the resin
washes have been in greatest favor as remedies for scale in-
insects, and in dry climates, such as are found in the West,
they have generally been more satisfactory than kerosene.
The experience of the Eastern and Atlantic coast States has
generally given the preference to kerosene, yet there are
many fruit men in Florida who prefer the resin wash. It
will be effective against all the insects listed herein, and
should, perhaps, be preferred before kerosene against the
wax scales if they are fully developed.
Whale Oil Soap.-The fish oil soaps furnish another
spray very commonly used, the quickness with which this
material can be prepared for use being a strong argument
in its favor by many people. It should be observed that not

all fish oil soaps are good insecticides, and, in fact, but two
of those that are widely used are of such uniform composi-
tion and strength that they are generally recommended by
entomologists. One of these soaps is known as Leggett's
Anchor Soap, and is manufactured by Leggett Bros., New
York City. Another is Good's Potash Whale Oil Soap, No.
3, manufactured by Jas. Good & Co., of Philadelphia. These
soaps, used at a strength of two pounds dissolved in one
gallon of water, almost equal the kerosene emulsions arid
resin wash against even armored scales. It is especially
desirable for use when a number of successive mild appli-
cations are required at intervals, when the strength of the
solutions can be readily varied.

University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs