The San Jose scale and its control


Material Information

The San Jose scale and its control
Series Title:
U.S. Dept. of Agriculture. Bureau of Entomology. Circular ;
Physical Description:
ii, 18 p. : ill. ; 23 cm.
Quaintance, A. L ( Altus Lacy ), 1870-1958
United States -- Dept. of Agriculture
United States -- Bureau of Entomology
U.S. Dept. of Agriculture
Place of Publication:
Washington, D.C
Publication Date:


Subjects / Keywords:
San José scale -- Control   ( lcsh )
San José scale   ( lcsh )
non-fiction   ( marcgt )


Statement of Responsibility:
by A.L. Quaintance.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029686182
oclc - 78485041
System ID:

Full Text



Issued August 12, 1l10.

L. 0. HOWARD, Entomologist and Chief of Bureau.


In ( 'hlret' of D'ciduou.. Fruif Inscl It I icsfif/ufltions.



R 33


L. 0. IOWAN iV I, Entomologist ailtil Chief of Bir-fan.
C. L. 1m A I.A.f, .:.i.'.int Enl toiologsV fnld A. citing C/'i f in I. scn'ce of Chief.
R. S. CLIFr.N, fire Nssisant.
\V. F. TASTET, C(ilf (C'hrk.

1. II. I 'I|ITTfENF.N, in ch/argc ofl,',( k crop w ild slorcd pfodlt i,.scct
A\. I. ]I','KI\S, ;I cl,'/i' ofjr'fcsl i.ic1 inl rstigatjl;oils.
\V. 1). IINrTF: in cl :. M. VKI{HSTE:I{, ;/i civrh,' of crIr, i atllIjoraygc ilisi ct hi viltigatfions.
A. L. QUAIN'r.\ NCE. in (, lii9i Of ,i cidnous fruit ilsccl il restigations.
E. F. Pm|.i.ii', ;S, 'n rjill of bee culture.
I). M. I 1, FI :,-. in RiOLLA P. ('Ci : ii-:. in ',rfn.ff of /dito ri 1 iorl'.
Mi. 1E(L (01.1 ID, librarian.

in rest igat ions.


A. L. QU'AINTAx' I-:, inl c 1r1r. .

" l;FI. JOlHNS'IN, S. \\. FoS.TI--, I1'. L. JENNF: P. R. JOINS, A. G. I[AMMAHI, It. W.
BlA.t I EH C. \\. IIOoKI(:, J. R. HORTON, \V. PosriIr-, J. I. (iLL. agenils (1nd
1,/ji p, s.
E:. W S'r'r, C(. II. (; i\ :. J. F. Z I :I .I, m 1 ,0to0oIgWlO icl vIssitifnts.
[Cir. 12-4]

CIRCULAR No. 124. Issued .i\giist 12, 1910.

United States Department of Agriculture,
L. 0. HOWARD, Entomologist and Chief of Bureau.

In ',f,','/of Decid o i.s Frit Insect Iuii, .il/lions.
The San Jose or Cliinese .scale .l.pidwiotus ir c'"'.i.s (Comistock)
infests l)ractically aill p)ortiins of its host 1)plaints that are above
groun(ld-tlie triiiiik. liilbs, and branchl,.--and when abundant it may
occur oin the leaves and fruit. Injury results from the (extraction, by
the scale inllsects, of the juices of thle l)luit. At first this merely
clhecks growth, but as the il-,ect.s increase in nuiulber the speedy kill-
ing of the branches and twigs follows, resulting fiiially in the death
of tle plants. III a(41dition to tlie extractioin, by the -cales, of sap as
food, the puncturing of the barlk by the lIhnder .-ucking mouth-p)arts
results in a (liseas(.(l and often pitted condition; the inner 1bark, or
camlbium, showing a reddish li.-col(iration, as exposed in cutting
wvitli a knife, and the bark it-.elf may crack, in -t one fruits exuding
drop- or masses of gum. A redldcninig effect is :Il.,o much in evi-
dlence as red( rings around the scales on the 1bark, especially of the
apple and pear, and on the fruits of t 1,ese plants, though not charac-
teristic of any one scale species.
On pPeacl tile scales have a tendency to infc,-t to a greater extent
the older linls and braniscls than the newer growth, as the wood
1 year old. On apple and(l pear, the terminal twigs are quite gen-
erally infested, and many of the young may find their way to the
fruit, settling principally in the calyx and stem cavities. Most
varieties of fruit trees and plants infestedI from the nursery, in
the al)sence of treatment, perhaps never reach fruiting condition.
a An extended recent accia'tnt of this insect will be found in Bulletin 62 of this
Bureau, '"The San Jns or 'hinese Scale," by (. L. MarlatT. which may be oblained
of ihe Siiperintendent of D,'ciinients, (,,ivertniritt Printing Offh TiI, WVali in-lI, D. C.,
fir 25 cents. Foreign applicants shnld .end 4 cents ad(ldi(iiniiil to cover posliage.
[Cir. 124]

Peachl trees will usually be killed in two or three seasons, while pear
or apple trees will maintain a feeble existence much longer. This
illsct, on account of its great similarity to certain other species of
,Calt inseccts, may l(ot be positively (letermine(d except by specialists.
The ('currence of diseased and dying branches showing severe scale
infe-,tation fiurnislies strong l)resumptive evidence of the presence
of this pest. but specimen', of infested twigs should be promptly
stibmiittedC to a qualified person for examination.
Tie ap)pearaice of a 3-year-o l)d peachl tree, presumably infested
from the nursery, is shown inl figure 1. The printcip)al limbs have

FIG. I.- \] i, I -r.i V uf i-\ .1r-()li1l I'ci, Itri' I l.r .lly iniijiiur' l' Ili t e San Jus, st.l', .t sp liutlts jiperniciosus)
I li, hIr:,'r ,,r:,i,,li,.s having, I l'
alrvaq IdN I well k lciletI, altltoiigi e\\ .I.l loots IIa ee d vtelo{)ed(I. A tree
in tllii-. (.lIit lOit g) (lera lly I I \ 1 1, S;\ I) e tl(horoutgl pruning
)111 (o f' d(ad aId hadIli njLjured wood anid subsequtenitly effecting the
control o)f thescl 1) 'prayiling.
'I'lc .li:1iractl'cr o ilj1I'ry to 11 aapl(e orclardl. in whliclh tlhe trees
w(r illfe'ted frilI o itsid S(.<, s o'',cs fo')ur or five earls earLlier, is slhown
ill fi.gue-. 2. Althiouigl Imlanl (dl' t1he limbs 2iid bl-ranclhes are ilnjtlred
or killeId, li ( Ptrees IIIN 1ma )e saved ad11(i 1b)rou1ghl t ilto Nvigorouis con(Ii-
ti j by I, tolI Iro l Ig 1)1'r11i1g, aItI 1If isu)Irinigr tlie control of the insect
il t lhe 'f It ilr .
I I i. I:-' I I


The mature San Jose scale is small, grayish in color, circular in
outline, somewhat convex, and with a nipplelike prominence in the
center. The female scale is about 1 millimeter in dianieter (about the
size of a pin head); the male scale is much smaller and elongate. (See
fig. 3.) The insect itself is beneath the so-called scale, this being
simply a waxy covering secreted by the soft, helpless, yellow "louse"
for its own protection. Where trees and plants are but slightly
infested its presence is not readily detecte(l by the casual observer,
but in tlhe case of severe infestation the bark of the tree and limbs

FIG. 2.-Appearance of an appkl orchard 1,,Illy infested by th e San luS. scale; iany uf the limbs and
brana is killed. (Original.)

will present an ash-lgray appearances(, land( on (cl,-er examination will
be found thoroughly\ icllrusted with the scal,-, which, when scrape(d
with a knife, will produce a yellowi"lh, oily fluid. When the scales
are abundant on the tree the foliage also will be thoroughly infested,
giving it a spotted and diseased appearance readily observalde some
feet away.
The San Jose scale passes the winter in an immature condition
fixed to the bark of the host plant, the small, dark-gray or blackish
scales being just l discernible with the unaided eye. In early spring,
[Cir. 124]

with the ascent of the tree's sap, the growth of the scale begins
n11d tarly in April in thle latitude of Washington tlie small, two-
w in,,. ;nctlive iiales issue from the male scales. After mating with

F1i;. :.-A pl,iiuij of the San Jose sc.ile, cniilirpd about 4 I inies; to tlhe righl. on peach; to the loft, on
apple. (Origiinal )
the f(ei,:lcs thie Inlls die. 'Tile feliales co()tti~tllle to grow iand in
sdtlt i (moth ! tli fl Oduction of livingr vougII-ililntev, yellow,
oval ('1cal Irun-,, \ li I'ir. 1241


without the aid of a hand lens, crawling here and there on the in-
fested plants in an effort to find a suitable place for settlement. The
young insect is active for some hours but soon settles, pushes its
slend(ler, threadlike beak into the plant, and begins to feed by sucking
out the sap. After this there is no further movement from place to
place, and the waxy covering, which often begins to develop 1)efore
the insect lias settled, soon covers it completely.
In about twelve days the insects molt and from this time on the
male and female scales may be readily d(listingllislle(d. Eight or ten
(lays later the males change to pupae, and in from twenty-four to
twenty-six days from birth the adult males emerge and fecundate
the females, which in turn reach maturity and begin the production
of young in from thirty-three to forty (lays from birth. An individual
female may give birth, on the seasonal averaLe, to about 400 young,
and as the life cycle of the female covers but a few weeks there may
)be several generations a year, the number varying according to lati-
tu(le. Tlie progeny front one parent during the season have been
estimated at 1,608,040,200 fenibles. It is thus eaVy to un(lerst aid
liow thlie insect can so quickly (dest,,roy the plants infested and \liy
promp)t reined ial i(easuries are so n,,;iry. Withi the al)pproa(ch of
tlie cool weather of fall, breed.ig gigradually sensess and tle ,.csalc in
all stages enter libernation. tMo-,t of thel older and also most of tlhe
younger ind lividltials perish (luring the winter, the survivors 1)eing
those alo)ut one-third or olne-hIalf grown, as -tated.


Tlie San Jose scale isl distributed from one region to another prin-
(cip)ally on nursery stock,, or bu(ddlinticg and grafting material.
The (danger of its disseniiiination in tlhis way is fully realized, and laws
are in force in tlhe majority of States requiring the inspI)ection of
nurseries and the dlest riction of infested stock. Traffic in nursery
produce is permissible only under the certificate of an official ento-
mologist or inspector t I iat t he st ock is free from the scale. In addition
to the actual inspection of nurseries, further safeguard is furnished
by tlie practice(, of most nurserymen (compul)ory in some States) of
fumigating the plants, before distribution, with hydrocyanic-acid gaIs.
After the insect once bconimes established in a locality its spread
is accoimplisledl by various agencies. As explained under the
natural history of the insect, it is capable of movement only during
a short period after birth. During tlis crawling stage the insects
are able to pass from tree to tree where the limbs are in contact.
But it is by agencies independent of itself that it is )principally
(list ributed. Prominent among these factors are birds, which may
alight upon infested trees, where the young insects may crawl upon
[C'ir. 124]

their feet and be subsequently depositedd in other trees, sometimes at
dlistances quite remote. It is probable that the young are blown by
strong winds from tree to tree; and they are carried by insects, such
as grasshoppers, lady(bird( beetles, ants, etc. The crawling "lice"
may be transl)ortedl considerable dlistances on the clothing of man,
on vehicles, or on horses or other live stock which may be in orchards
Io'r alny purpose.
Tlie suggestion that the insect may be (lisseminate(d by means of
sca.le-infested fruit (see fig. 4) hlas been frequently made, but it is
tlihe consensus of opinion among American entomologists that this
anger wlilile undoubtedly existing, is negligil)e.

"l1.. -- iiIlwil .11ill lI:,lly infir-.',l w il li I lie Sg;i I .I s' .cr:lv. i Original.)


'I'lle S;li ,Jose s('al' ill'f'stN p)ralct icalIv :ill dIecidIolIs I'nulit trees,
sUi'i -N aplJi)J)l('r,)('ar, J'ac'lI, )liIli, (et(c., al(Id also1) llayIV orlam entill andI
sliul1, tres. It is, I)owe(ver, Sriousl :1 destrti-ctiv'' to 41 mu'ch smaller
nflhlI :flT ta111 thlit uponl which it IIayV actN : lly m intain its existence.
'I'lle ollowig list ol o(od1 l)lats, as 'co iIJ)l (I by )Dr. W. FE. Britton,0
i1cIlldes I iiise tIlat are com only oI badly infested:
l ,,u'rt of di,, (',-iii irliut Agricultural kxpjcriiin 'int Staliii, 19(l2, ]'arl II. 2d
Pr1,0 rt, f 4l iri In2 1)ii)](gii.l, pp. 132-13S.
I O'l. 1241

Acacia sp. Lintner, Felt, N. Y.; Alwood, Va.
Akebia sp. Felt, N. Y.
Ak'ebia quinalta Decaisne. Alwood, Va.
Amnelanchier canadensis Medic., and other species. Shad-bush, Juneberry. Britton,
Koehler, Conn.; Alwood, Va.
Citrus trifoliala Linn. Scott, Ga.; Alwood, Va.; Gossard, Fla.
Cornus alba Linn. var. sibirica Lodd. Britton, Conn.
Cornuts bailey Coult. & Evans. Gould (in N. Y.)..
Comnus sanguinea Linn. Britton, Conn.
Coioneaster sp.? Britton, Conn.; Lintner, Felt, N. Y.; Card, R. I.
Coton easter vulgaris Lindl. Alwood, Va.
Cratxgus sp. Hawthorn. Britton, Conn.; Lintner, Felt, N. Y.; Alwood, Va.; Smith,
Cratxgus cordala Soland. Koehler, Conn.
Cratxg us o.xyacantha Linn. English hawthorn. Britton, Koehler, Conn.
Crataguis ,orrif'ica Linn. Koehler, Conn.
Crat;i'gus crus-galli Linn. Koehler, Conn.
Cydonia vulgaris Pers. Common quince. Britton, Conn.; Lintner, N. Y.; Alwood,
Cydonia japon';c( Pers. Japanese or flowering quince. Britton, Koehler, Conn.;
Lintner, N. Y.; Alwood, Va.; Johnson, Md.
Fagus syh'litica Linn. var. purpturci Ait. European purple-leaved beech. Smith, N.J.
Jughlans shitboldiana Maxim. Japane-e walnut. Britton, Conn.; Alwood, Va.; Sher-
man, N. C.; Smith, N. J.
Ligustrif vulgare Linn. Common privet. Alwood, Va.
Populuts sp. Poplar. Britton, Conn.; Smith, N. J.; Sanderson, Del.; Felt, N. Y.
Populus deltoides Marsh. Carolina poplar. Britton, Conn.; Rolfs & Quaintance,
Fla.; Alwood, Va.
Popuhltsnigra Linn. var. ifalica Du Roi. Lomlbardy poplar. Brit ton, Koehler, Conn.;
Rolfs & Quaintance, Ila.; Alwood, Va.
Prun us ainygdnlus Stoke-. Almond. Lintner, N. Y.; Alwoo(d, Va.
Prunus rin,,-Uaca l.inn. Apricot. Lintner, Felt, N. Y.; Alwood, Va.; Smith, N. J.
Prunus ur in Linn. Sweet cherry. Britton, Conn.; Lintner, Felt, N. Y.; Alwood,
Va.; Smith, N. J.; C'ockerell, N. Mex.
Prunus punila Linn. Koehler, Conn.
Prunus ptuiniil var. besscyi Waugh. Sand cherry. Alwood, Va.
Prunus ceras'feri Ehrh. var. atropurpiirca Dipp. (P. pissa rdi). Purple-laved plum.
Britton, Conn.; Felt, N. Y.
Prunus doinWestra Linn. European plum. Britton, Conn.; Alwood, Va.
Prunus horlullana Bailey. Wild goose plum. Alwood, Va.
Prutrus japornica Thunb. Flowering almond. Britton, Conn.; Felt, N. Y.
Prunus marititna Waugh. Beach plum. Koehler, Britton, Conn.
Pruinus persilca Sieb. & Zucc. Peach. Britton, Koehler, Conn.; Lintner, Felt, N.Y.;
Alwood, Va.; Cockerell, N. Mex.
Prunus triflora Roxbg. Japanese plunm. Britton, Koehler, Conn.; Alwood, Va.
P'runus serotina Ehrh. Koehler, Conn.
Prunuts virginiana Linn. Chokecherry. Koehler, Conn.
Ptclea trifolinta Linn. Hop tree. Fernald, Mass.
Pyruscoinimunis Linn. Pear. Britton, Koehler, Conn.; Lintner, Felt, N. Y.;
Alwood, Va.; Cockerell, N. Mex.
Pyrus sinensis Lindl. Send pear, including Kieffer. Alwood, Va.
Pyrus baccata Linn. Koehler, Conn.
Pyrus nimahis Linn. Apple. Britton, Koehler, Conn.; Lintner, Felt, N.Y.; Alwood,
Va.; Doten, NXe'.; Cockerell, N. Mex.
48873- Cir. 124-10-2


Pyrus sp. Crab apple. Britton, Conn.
Ribcs ox.yacaritoides Linn. Gooseberry. Britton, Conn.; Lintner, Felt, N. Y.;
Alwood, Va.; Troop, Ind.
Rin(s mi'atumi Pursh. Missouri or flowering currant. Lintner, N. Y.
Ribes rubruim Linn. Currant. Britton, Conn.; Lintner, Felt, N. Y.
Ribls tigrunm Linn. Black currant. Alwood, Va.
Rosa sp. Britton, Conn.; Lintner, N. Y.; Alwood, Va.; Cockerell, N. Mex.;" Bur-
ge", Ohio; Troop, Ind.; Gould, Md.; Scott, Ga.
Rosi carolina Linn. Koehler, Conn.
Rosa lucida Ehrh. Koehler, Conn.
Post i irginiatia Mill. Koehler, Conn.
Rosa rugosa Thunb. Britton, Koehler, Conn.
Salix sp. Willow. Britton, Conn.; Felt, N. Y.; Sanderson, Del.
Sali.x lhidaN Muhl. Koehler, Conn.
Sali.r p)enfandra Linn. Laurel-leaved willow. Lintner, N. Y.; Alwood, Va.
Salix 'i itellina Linn. Koehler, Conn.
Salix babylottica Linn. Weeping willow. Lintner, N. Y.; Alwood, Va.
Salix thm ilis Marsh. Koehler, Conn.
Salix in-ca-ia Schrank. Koehler, Conn.
Sorbius sp. Mountain ash. Felt, N. Y.; Hunter, Kans.
Sorbus americana Marsh. American mountain ash. Britton, Koehler, Conn.; Alwood,
Sorbus (lu"-uparia Linn. European mountain ash. Britton, Koehler, Conn.
Sorlbus mclanocarpa C. Koch (Aronia nigra Koehne). Black chokeberry. Koehler,
Syrmphoricarpos racemosus Michx. Snowberry. Felt, N. Y.; Smith, N. J.
Siyriinga vulgaris Linn. Common lilac. Burgess, Ohio; commissioner of agriculture,
N. Y.; Troop, Ind.; Alwood, Va.
Syr;iga persica Linn. Persian lilac. Britton, Conn.
Tilia sp. Basswood, linden. Britton, Conn.; Lintner, commissioner of agriculture,
Tilia americana Linn. American linden or basswood. Britton, Conn.; Alwood, Va.
Toxylon pomiferumn Raf. Osage orange. Britton, Conn.; Lintner, Felt, N. Y.;
Alwood, Va.
Ulmus sp. Elm. Lintner, N. Y.; Webster, Ohio; Troop, Ind.
Ulnaus americana Linn. American elm. Britton, Koehler, Conn.; Alwood, Va.
('l inus caimpestris Smith. English or European elm. Britton, Conn.; Felt, N. Y.;
Smith, N. J.
This list might be materially extended by recording those plants
upon which the insect has at various times been taken but to which
it is not especially injurious. The fears earlier expressed that the
scale would eventually seriously infest our native forest growth have
not been borne out, and in effect it requires treatment only on fruit
trees and on ornamental trees and plants.


The San Jose scale is subject to attack by numerous predaceous
and parasitic enemies, which rend(ler important service in its control.
Practically, however, the combined influence of these several agen-
ci(s is not sufficient to make up for the enormous reproductive
[Cir. 1'-4 ]

capacity of this insect. To preserve the plants from destruction,
its control must be accomplished by artificial means, such as the use
of sprays.
Among the more common predaceous insects which are observed
feeding on the scale is the so-called pitiful ladybird (Mi1croweisea
[Pen tilia] miisella Lee.), illustrated in figure 5. This very small,
convex, black beetle may generally be found by any observant per-
son on scale-infested trees.
Another species that feeds very commonly on this and other scale
insects is the twice-stabbed ladybird (Otilocorus bivulnerus Muls.).
This is a very near relative and almost identical in appearance to

jCi~ ..
*;AeH - /^c'ES>


FIG. 5.-The pitiful ladybird (.\ficreiwi(s(a [Pentilia] misella): a, Beetle; b, larva; c, pupa; d, blossom end
of pear,showing scales with larve of Microweisea feie'irig on Ihlini. and pupa, of M14roweisea attached
within the calyx. All greatly enlargeil. (From Howard and Marlatt.)
the Asiatic ladybird (Oclilocorus slidis Rossi) (see fig. 6), which was
introduced into this country from China through the activities of
Mr. C. L. Marlatt, of the Bureau of Entomology, in the hope that
its introduction would result in the control of this insect. The
Asiatic ladybird, however, unfortunately proved to be subject to
certain native parasites, while the necessity of spraying for the scale
destroyed its food supply to such an extent that it was unable to
maintain its existence.
Included among the parasitic Hymenoptera are certain natural
enemies of an entirely different kind-very minute, four-winged
flies (see fig. 7), which deposit their eggs upon or in the scales,
[Cir. 124]

the resulting grubs consuming the body substance of their host in
the course of their growth. The abundance of these small parasites
varies greatly with the locality and the time of year. Dr. L. 0.
HIoward,a who has given much attention to the parasites of the San
Jose and other scales, records for this species the following: Apheli-
ru.s fuscipennis How., Aphielinus mytilaspidis Le B., Aspidiotipha-
gu.s citrius How., Anapies gracilis How., Physcus varicornis How.,
Prospalta auranidi How., Ablcrus clisiocampe Ashm., and Rihopoideus
cdrin us How.
\; -


1I P .

', a I ,l

Fi,'. 6.-The Asiatic ladybird (Chilocoru similis), almost identical with the twice-stabbed ladybird (C.
bivulnru.), predatory on the San Jose scale: a, Second-stage larva; b, cast skin of same; c. full-grown
lIrva;. d, method of pupation, the pupa being retained in snlit larval skin; e, newly emerged adults not
yet ruloreil; f, fully colored and perfect adult. All enlarged to the same scale. (Fromni Marlatt.

Parasitism by these insects is indicated by a small round hliole in
the scale covering of the insect, through which the adult parasite
hali., nadle its escape. Any orclhardlist, however, may satisfy him-
self as to thle presence of these little friends by inclosing in a glass
vial ai badly infested twig, for in tihe course of a few days the minute
flies, if present, will bergil to emerge.
Con si(lerable attent iOni has been given to the subject of fungus ( dis-
,eases of the Saln Jose scale, andl l|iimeterols attempts conduLctetd in a
ti, ,'r, uighly s.cieoitific manlner, notably by Prof. P. II. Rolfs, director
of tlie F,'loridla .Agricultural Experiment Station, have been made to
a Biul. 4;2, ,f lInitl-ojji ogyv, U. S. Dvpl. of Agririiltlure, pp. 58-62, 1906.
[C ir. 124]

utilize one of these parasitic plants in the control of the insect.
The fungus in question, Sphwrostilbc coccophila, is cosmopolitan in
its distribution, infesting many diaspine scale insects, and in Florida
and the territory adjacent to the Gulf it is quite generally present on
scales in orchards and on shade and forest trees. Its abundance
and effectiveness, however, depend upon certain weather con(li-
tions, and therefore vary considlerably.
As has been already stated, the San Jose scale, in the absence of
proper treatment, will quickly. bring about the death. of most plants
of economic importance. Its discovery, therefore, whether in
orclhards or on prized fruit trees and other plants in the yard, should
call for prompt steps to effect its control. It has been amnply (demon-
strated that tlihe scale may be very successfully controlle(j, and
"1" 00 n rol0 n

-' --- 1' 7
,:" " "l i" t' "" "-

-i N
,/ / :, ,"f .7 V '

FPi. 7.--A.spididili/,/rl'ilux cilrinui', a Iyi 'nii l i'r- p rasi e of i lit San Jose scale. ( ; re:ial ly enlarged.
(From lhoward. )
practically its p1es ll'e merely requires one thIoro(ugh treatment
cduring the dornimant period e;i(chi yeari. Oiln account of the general
(distribution of the pest, extermi.i(ion is ii n ,1 (.niscs out of the
(quest ion.
Where plants are thorollughly incrustel, with collnequent death of
branches andI sitiiut ig of girow hwi. it will generally be advisable to
dig out tlie tlre's at once and replace within new ones. Previous to
spraying infested tre('e, the dead1 and weakienel woodl should be
pruned out, which will simplify the work of spraying and will hasten
the formation of new sound wood.
There are several scale waslhes which may be employed in the
control of the insect, and the one should be slec.t(ed which can be
most conveniently used and which is economical under the circnum-
stances. Thus, for spraying onl a large scale tlhe orchardist could
properly afford( exl)en(litures for the construction of cooking outfits
['ir. 1241

for limnie-sulplhur wash which would not be justified where but, a few
plants were involved. For a few plants it would be better to use
so,,me onle of the prepared wvaslies put up by manufacturers. In fact,
many- large orcliarlists prefer to use sprays of this class in prefer-
ence to making thle washes at home. Thle possibility of injury to
the trees from tihe sprays must also be borne in mind. All treat-
milents, if possible, should be made duIring the dormant period (this is
to say, in late fall or early spring, or even during the winter in mild
climates), since at this time waslies may be applied at much greater
strengths than when the trees are in foliage. The aim is to use the
wvash about as strong as the tree will stand, thereby securing the
maximum killing effect upon the insects. Used in this wvay the
waslis of the 1petroleum or kerosene series are most likely to cause
injury to the fruit buds and tender twigs, and tlhe lime-sulphur
washelcs least likely to do so. Whale-oil-soap sprays as recommended
for (do'iimanit trees are comparatively safe, though reports are at
fhand of injury to fruit buds, especially from fall applications. Stone
fruits, such as peachl, pll1m, etc., are more susceptil)le t) injury from
spli5'vs thail apple and pear, and on the former the lime-sulp)hur
s)rays sould always be ulsed(. Petroleum andl(l ]iscible oils are
more frequently used on apple anid plear, an(d owing to their sl)read(l-
ing anid p,'it rating qualities are perilhapls mor(' effective in destroy-
ing tlhe scales on the terminal twigs, which are infested to a greater
extent in the case of these fruits. The several sprays in use may be
c.hsidlered i(lder tlhe following headings: (1) Lime-sulphur wash
series; (2) petroleum oil series (including miscib)le oils), anl(I (3) soap
Waisl I series.
For many years the cooked lime-sulphur wash lias been the main
reliane in the control of thl scale. It is made according to the fol-
lowinirg formula:
S )' ili . . . . . . . . . ..... ... . . .... . . .. . . ..po ndls. 20
Sulphur (flour,,r fl'wr)............................. d. ---.... 15
\\;il,'r to eii.,ke ........................ ................... gaillons.. 50
I['lat ill a c-ooki, barrel or vessel about otne-third t1' lite total
q(latity o(f wNater r,(quire(l. When the water is hot al d all t lie me
and ait mnce add all thle sulphur, which( previously shoulli have been
malde into a thick i)ast o witlh w at er. After tile liie lias slaked(l, about
a:oiher third of thle Nvater should be adIdel, )pref'irably hot, 4an1d tie
cokin. should Ibe coiitinu'I for onei hour, whlen thle( final (lilutio,
,uI;y6 11' mlade, sii.g eit her iot or cold water, as is most (cmoivellienlt.
lie bo,,ilinlg du(1 to ihe slakiigr of the lime horoghlly ,ixe(s tlie
inlr,,dliillt- n1 i!u.e si,;irt, Iut sutlbsequ'en1ft( stirring is ,ecessary if tlihe
W ial, i- ,ok4,di by lir.ect h ia( in kettles. If cooked by steami, no
I 'ir. 124


stirring will be necessary. After the wash lias been prepared it must
be well strained as it is being run into the spray pump or tank. The
wash may be cooked in large kettles or, preferably, by steam in bar-
rels or tanks.
This wash has proved entirely effective in controlling the insect on
all plants, so far as preserving their life is concerned, and lihas been
especially satisfactory for stone fruits. For the apple, however, it
has not in all cases been so satisfactory, as difficulty is experienced,
especially in the case of large trees, in nmakillg the application suffi-
ciently thorough to kill all the scales. The spotting of the fruit by
the progeny of those that escape renters it unsightly for market pur-
poses, thoughll its intrinsic value is but little reduced. The presence
of the scale is furthermore very objectionable for the reason that cer-
tain foreign governments and certain States in this country rigidly
quarantine against fruits showing tlie presence of this insect. Con-
sidleral)le loss on fruit exported thus results to orchardists and
Some apl)le growers rely principally upon the oil sprays, or use
themlll at least every otlir V Vlr, alternating witlh the lime-sutlphur
wash, and in this way keep the s(cale well in check.
'()N( E.' THV ['1 ;1) 1.1MK-SI .riH-' .Lo I"IO.NS.
Tle inc( lon venieice ei xl)ri'ne'dI in pr')paring thie lime-sulphur washli
by )cooking with steam or in op)i, kettles at home has been one of
the l)rincipial objections to this l)r-avy. C('orii i i minufact urers have
therefore put on t lie market concentrated solutions of lime-sulphur
wash, which have only to be diluted witli water for iise. The(,se com.-
miercial washlis have prov(ld to be about ;i effective in controlling
the scale as the well-cooked limi(-,tilplhur w;, and(, although some-
what more eXl)pesive, have been adopted( by many comlmver.cial
orclhar(lists in pr(efereirce to the homie-l)relmired spray. Thliey are
especially useful for the smaller orchar(list, whose intere.,ts do not
warrant tlie construction of a cooking plant. In other ways, too,.
they possess advantages; for i(;amIce, those iii,. the commercial
waslies nmay live always on hand a stock solution, so that the spray
nmay be quickly l)reptr((ed and( ailvantuage fitlken of favorable weather
The question of tlie preparation at homie of concentrated lime-sul-
phur solutions which will not crystallize upon cooling, thus duplicat-
ing essentially the commercial product, lias been the subject of inves-
a Experimeiiits made by the Bureaul of Enlti ,lny indicate the practicability of
successfully fumii igat i ig,.-a1e-i ifel ed appli ini einded for export or other 1 iitde. (See
Bul. 84, Bur. Ent., U. S. Dept. Agr., 190!.)
[V'ir. 124]

tigation by several entomologists, notably by Cordley in Oregon,
Stewart a in Pennsylvania, and Parrott b in New York State. These
gentlemen have demonstrated that it is practicable for orchardists
to prepare concentrated stock solutions of lime-sulphur wash for
illmmeliate or later use. Several orchardists have already adopted
t is plan, andl it will dloubl)tless come into more general use -in the
future. The details of thile preparation of concentrated lime-sulphur
solutions can not properly be given in the scope of this circular, but.
those interested should secure, if possible, copies of reports on the
work from the directors of the respective experiment stations.

In the earlier exlperimeints witli tlie lime-sulpluir waslh in the East
Inmm efforts were Illadle to avoid tlie necessity of cooking tlhe wash
bv utilizing, to dissolve thle sulphultr, tlie lheat generated by the slak-
ilg of tlie lime, or supplemenltilng tills by tlie alddlition of a quantity
Of caustic sodCa or potashl. Tis preparation, formerly designatedd as
sell-loiledl lime-sullphur waslh, lias now largely, if not entirely, fallen
iliti d-lisuse, and tle slpra under considleration is essentially a difter-
'lit preparation a(nd was developed primarily as a fungicide.
Ex'perilments made by tlie Bureau of Entomology in tlhe vicinity
4o WVasliington iln 190s, however, have shown that this self-boiled
wash, hy idestrovying tlie young insects and interfering with their
estabslisment, is an excellent summer treatment for tlhe San Jose
scale. It is also effective in dlestroying aphlides and, in addition, as
stated, will prevent numerous fungous diseases, as established by
Pr11f. WV. M. Scott, Of tlhe Bureau of Plant In(lustr.v. Its use is espe-
(c1t ally recoil mmentlded for scale-infested fruit trees which should receive
alIl)lillatio (Is of, a ungi'cile alnId wiich may l)e more or less affected
with apliidles. By tlhe addition of airsenate (if lead, at tie rate of 2
po1n(Is to 50 gallons of spray, tlie wash also lbec(omes effective
against lifting insects, such as tlhe cod(ling )mothl and plumn curculio,
awld tlils fuIrnisles as 'early an all-around spray as anything liat
p]l'esle t k oll(wnVl.
It is possiN!ble 'Iat thite 0m111 i'l coMncenltl rated l'CIiime-sulJph i ur waslh,
Jrl'Vioul, refelrredI to, uls(ed at lie rnile Iof I ,- gallons to) 50) gallons
of Witer, wo1l desCtr'o V ,iianr of tile 'oul Saii Jose scales. It ha1s
l)t'(' slw tio be (1 ex('cellent 'fullgicidie, and at tilhis strengthi hnot
iljIri,,(iis to tl'e f'oliage. Arsenate ol' oletad 1a1v also) be added, as in
tlit (..-t'e Cf tlie self-Iboilled wi'sli.
In utsilg tlie s'll'-l)CileCI Ilime-suilpiIlulr washl aIs a. scale treatment,
hIo('vveVr, 'esl 'i pai, lls sild()ICI Ibe taken to ('(lit lite limbs and branches
a I1til. !l)1, Pa. Slati (C(ill. Agr. Eixp. Slia. (Slate ( ll'ge', I'Pa.), 1910.
b .,l :(2, N. Y. A.r. Exp. Sia. ((Geineva', N. Y.), 19m)09.
I iir. 12 l

of the infested trees, and(, on account o)f the presence of the leaves,
careful work will be necessary to accomplish this. This waslh is
made as follows:
Stone lime---- ............................................. pounds. 8
Sulphur (flour or flowers) .................................. do-... 8
W ater to make ......--..................................... galliins.. 50
The lime should be placed in a barrel and enough water poured on
to almost cover it. As soon as the lime begins to slake the sulphur
should be added, after first running it through a sieve to break up
the lumps. The mixture should be constantly stirred and more
water added as needed to form a thick paste at first and then grald-
ually a thin paste. The lime will supply enough heat to boil the
mixture several minutes. As soon as it is well slaked water should
be added to cool the mixture and prevent further cooking. It is
then really to be strained into the spray tank, diluted, and applied.
The stage at which cold water should be poured on to stop the
cooking varies with different grades of lime. Some limes are so slug-
gish in slaking that it is difficult to obtain enough heat from them to
cook the inixture at all, while other limies become intensely hot on
slaking, and care must lbe. taken not to allow the boiling to proceed
too far. If the mixtlire is allowed to remain hot fifteen or twenty
minutes after the slaking is col)mpleted the sulphur gradually goes
into solution, combining with the lime to form sulphids, which are
injurioius to peach foliage. It is therefore very important, especially
witli hot lime, to cool the mixture quickly by adding a few buckets
of water as soon as the lumps of lime have slaked down. The intense
heat, violent boiling, and constant stirring result in a uniform mix-
ture of finely-divided sulphur and lime, with only a very small per-
centage of the sulphur in solution. It should be strained to take out
the coarse particles of lime, but the sulphur should be carefully
worked through a strainer. The mixture can be prepared in larger
quantities if (lesirabl)le, saiy enough for 200 gallons at a time, making
the formula 32 pounds of lime and 32 pounds of sulphur to be cooked
with a small quantity of water (8 or 10 gallons), and then diluted to
200 gallons.
The first application should be given when the young scale insects
are beginning to crawl, which time will vary according to locality.
In the neighborhood of Washington this will be about the middle of
May, earlier in the South, and later in the North. This one treat-
ment, if thoroughly applied, will do much to check the increase of
the insect and to protect tlhe trees from serious damage until the
more thorough winter application can be made. A subsequent appli-
cation should be given, if practicable, in the course of five or six weeks
in order to destroy the young scales of the second generation.
[Cir. 124]

/ "- --- L L....

S- 16

IU under the heading "Petroleum-oil series" are to be included kero-
sene and crude petroleum, either pure or in emulsion, and the so-
called miscibl)le 4)ils.
Purw l-crosuiic tr(atinit.-Pure kerosene hlias been more or less
recommlfendlled for spraying trees badly infested with the scale, but it.
lias nevei, been very generally employed. There is no question of the
efficiency of such an application in the destruction of the insects,
but tlie great danger of injury to the plants precludes its general
application. Treatments of pure kerosene should be made only dur-
ing briglit days and should be applied through a nozzle with a very
fine aperture. Only the minimum amount of kerosene necessary to
cover the trees should be given, and care is necessary that the liquid
does not puddle around the roots of the trees.
Purc crude p identically tlie same manner as pure kerosene, and the same cautions
as to its utse should be remembered. The crude oil empl)loyed in the
East is known as "insecticide oil" and has a specific gravity of 43
to 45 degrees on the Beaum6 scale.
KU.( ,lineC i,',lsion (stock solution 66 per cent oil).-Kerosene emul-
sion is made after thle following formula:
Ker,,seiie (coal oil, lamp oil).............................. gallons.. 2
Whale-oil s,,ap or laundry soap (or 1 quart of soft soap).... pound..
W ater.................. ................................. gallon.. 1
Dissolve the soap in )oiling water; then remove vessel from the
fire. Imme diately add the kerosene, and thoroughly agitate the
llixtlure until a creamy solution results. The stock emulsion may be
more clnveniently made by )pouring the mixture into thle tank of a
spray pump and pumping the liquid through the nozzle back into
the tank for some minutes. The stock solution, if well ,na(de, will
Keep fr some montIs, and is to be diluted before using. In order to
make a 10 per cent spray (the strength for trees in foliage), add to
i (each 1 gullon of the stock solution about 52 gallons of water. For
S20 anid 25 per cenit emiulsinis (for use on d(oi'mant trees and plants),
1use, respl)ectively, about 21 galls and 1 kI gall, ns of water for each 1
gallon of st)(ock einulsion. Agitate the mixture in all cases after
alddiig the water. The preparatiion of thle emnulsion N will l)e simplified
by the use of a naplhtlla soap. No heat will be required, as thle kero-
senie will com(nlbiiie readily with the naphtlia soap in water when thor-
oughlly agitated. Of nplilhtlla soapl, however, double thle quantity
given ill tihle above formula will be required, andii soft or rain water
sli uld be llwsd in imakiilg the emulsion. In regions where tihe water
is "lI''rd" hills shiouhl first 1be )roke, with a little caustic po)tashl or
sod1:1, s5IC]i :I-. common( lye, I )(f4 ire use for dilition, to l)revent tlie
soIp frio, combining with ti lie, o1t1 r (W agnilsia, ('Si PlIseIt, tlius liblerat-
iHg siI o()f the lk(r,)s;li'; or rai water imaiy be enp)loyed.
I 'li%. 1 Ij


Crude petroleum emulsion.-Crude petroleum emulsion may be pre-
pared in identically the same way as descril)ed for kerosene emulsion,
substituting crude petroleum for kerosene. The s-aLiie dilutions for
winter and summer spraying should be made as prescribed for kero-
sene emulsion, but it should be noted that for summer treatments
of trees in foliage the kerosene emulsion is preferable, as it is less
likely to cause injury.
Miscible oil.s.-Under the heading "Miscible oils" are to be desig-
nated several proprietary preparations which are .essentially petro-
leuin oils with the addition of a vegetable oil and an alkali, to secure
ready saponification with water. These come in concentrated solu-
tions and the spray is prepared by adding a specified amount of water.
In point of convenience they leave little to be desired. Miscible
oils are coming into increased use in place of kero()sene or crude petro-
leum, either pure or in emulsions, and have a distinct usefulness as
winter sprays about the same as have the concentrated lime-sulphur
solutions. As lhas been indicateAd, the petroleum oils are at times the
cause of injury to twigs and fruit buds, and it is a question of judg-
ment whether, under conditions of severe scale infestation, the petro-
leum oils or the sull)hur solutions should be used. The petroleum
oils, on the whole, are more effective and the danger of injury from
them is less to pome thai to stone fruits.
The practicability of making iiiscible oils at home has been inves-
tigate(d by Prof. C. L. Penivy, and (lie lias shown it to be entirely
feasible, as detailed in the public t ions cited below.
Practically the only soap) wash which lias come into extended use
against. the Sai Jose scale is tliat made from lwhale-oil soapl. This is
use(l mostly on dormant tres, tlhe saIp being employed at the rate
of 2 pouin(ls to the gallon of wa tv r. A potash whale-oil soap is prefer-
able and should contain not more than 30 per cent of water. Soda
soaps, while perhaps cheaper, will be likely to solidify on cooling
when used at t lie strengt-i above indicated, and are hence forced
through tlhe spr-iy-pump) nozzle witli (difficulty. For spraying trees
in fo)liage, tlie soap) sl(ould be usedl at the rate of 1 pound to 3 or 4
gallons of water, or somewhat weaker.
The washes Ias above described are applied b)y means of some form
of spray pump, tlhe size and character (depending upon the size of the
plants to b)e treated. For small plants, such as ornamentals, hedges,
etc., a bucket pump (fig. 8) or knapsack pump (fig. 9) will be satis-
factory. Tlhe barrel form of pump, however (fig. 10), will permit of
more thorough work and will be suitable for orchards of some size.
a Bul. 75, Del. Cl. ol. A\r. Exp. Sta. (1906).
Bul. S5, Pa. State Coll. Agr. Exp. Sta. (191)s). State College, Pa.
tCir. 1-'41



3 1262 09228 3109

It muy be placed in a wagon or cart or mounted on a sled. For large
commercial orchards the hand-power tank or gasoline outfits arc
It is (quite practicable, however, in case but two or three trees in
a yard are to be treated, to apply the wash to the limbs and branches
__ ~Tg^ :*


FIG. 8.-Bucket spray pump suitable for use in yards. (Author's illustration.)

FIG. 9.--Kn:lpsack sprayer suitable for praying
lu.v- -griwiiig plants. author's' s Illustration.)

FIG. 10.-A barrel sprayer,suitable for orchard
or similar large-scale work. (Author's illus-

1, iii,.iOf of od1(1 c('tls or brushes. Wvhale-oil soap ) is excellent for
ti s S1urpoee(. Sc1',ere J )riiig of the trees is usually desirable in
Sl(] 'i IC ,'1 ( ,"C .
J. wMs \\nsON,
S I'tt(IPcf oJ zlf/t ticllu 1.
WASIll NG'TON, D. C., MAly 27, 1910.
l'ir. l211