Recommendations for control of caterpillars on cabbage in the south under present wartime conditions

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Material Information

Title:
Recommendations for control of caterpillars on cabbage in the south under present wartime conditions
Physical Description:
11 p. : ; 27 cm.
Language:
English
Creator:
Reid, W. J ( William John ), 1902-
United States -- Bureau of Entomology and Plant Quarantine
Publisher:
U.S. Department of Agriculture, Bureau of Entomology and Plant Quarantine
Place of Publication:
Washington, D.C
Publication Date:

Subjects

Subjects / Keywords:
Cabbage -- Diseases and pests -- Southern States   ( lcsh )
Caterpillars -- Control   ( lcsh )
Insect pests -- Control   ( lcsh )
Genre:
federal government publication   ( marcgt )
non-fiction   ( marcgt )

Notes

General Note:
Caption title.
General Note:
"E-591."
General Note:
"April 1943."
Statement of Responsibility:
by W.J. Reid.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 030284935
oclc - 779478453
System ID:
AA00025072:00001

Full Text







Unted States Departmcirnt ofL A-:-'icuit~xre
Agz'ThcturiJ. -esea:-rc.h ACiriiiis:rt5
13voa-u of' 1,ntorm-oJoy and0 Plaint Quarrnt ine




RECOMI DAT ION~S POR IO1R0LOFC ?ZLR TOABG
2T71-1 8O~jTH TjIz_1DTi PSN-2 WAXRTLDL MXOJIMC017S

By W. J. R eid, Jr., Di--ision of' Jruck Crop Insect investigations'



COj LTTS

Page
Introduction ------------------ 1
Princip.1 insects involved 2
Use of' insecticides : ------3
Cotrol during plant preheading period 4
Soil-ihab it ing uwrm
aa- ceplars, corn eari 'orm, :-nd
climbing cutwormns------------ 5
Control durin- -o", nt heating period o
Methods of' using dusts ;,knl sP rays ----9
NItural control rieasures 10
Where insecticides m be obtained ---- 10 Smma ary - - - - - - - - - -10


iINT ROL,3TI0\

Cabbage is onc o-f the important ve,-etable crops for which increasp rroduction is 'ua'ged. by the authorities to meet wartime needs. Duing the poriocl of' its growth thInJs crop is often damaged by one or more lkinas of in~sect pests, including several species oil ca.terillars, or nwrrnsI1 Experiments by wvor-kers of' this Bureau dr.ring the last 10 years have show that these caterpillars can be controlled at any
stage of the growth of cabbr-e by the application of v.rous insecticides. The supply of some of' those insecticides, especially those




In cooperation with the South Carolina Agricultural Experime nt
-Station










oontaIning rotenone or pyrethrum, has been cutaiLed seriously by war conditions. The situation with respect to the availability of rotenone-containing materials is particularly critical because this insecticide is obtained from the roots of several species of tropical or subtropical plants such as derris, cube, barbasoo, tuba, and timbo, imported principally from areas in the South Pacfic which have been cut off as a result of warfare. In order, therofore, to conserve supplies of rotenone-containing insecticides for use on certain cops and on certain animals where the need is cons sidorod most urgent, tho War Production Board has issued a conservation order specifying the use of those materials. The provisions of this order do not permit the use of rotonono-containing insecticides for the control of insects on cabbage.

The principal purpose of this circular, therefore, is to furnich home gardoners, commercial growers, insecticide dealers, and other intor stod -oorsons with reccrnmeondations as to the use of available insecticides and other control measures for combating catrpillr-rs on cab"bago under the emergency conditions resulting from the war. While the information in this circular will be of particular value in the South, the recommendations contained thoeroin will also apply to other p,rts of the country.


PRICIAL INSECTS ETVOLED

The principal species of caterpillars that cause damage to cabbage in the South are the cabbage looper, the diamondback moth (also known as the cabbage plutella), the imported cabbageworm (also known as the common cabbageworm), the cabbage wobworm (or budworm), the corn oarworm (also known as tomato fruitworm and cotton bollworm), and scvoral species of true cutworms. Several other species, including the cross-striped cabbage worm, somotimos occur in injurious numbers in certain areas. All these caterpillars are the immature stages of moths or butterflies.

The cabbage looper, the imported cabbagoworm, and the caterpillar (larva) of' the diamondback moth are green and feed on the lcvcs, bud, or head of cabbage plants. They are sometimes known as the "grooeen worms" of cabbage. The looper may be distinguished by its habit of forming a hump in its body, or "looping," as it crawls. The imported cabbag eworm has a velvety appearance, a slender orange-colored stripe downm the middle of its back, and a broken yellowish stripe along each side of its body. The cabbage looper and the imported cabbageworm are about 11 inches long when full grown. Caterpillars of the diamondback moth arc only. about one-third inch long when full grown, are somewhat tapered at each end, and usually wriggle actively when disturbed, ofton dropping from the plant and hanging by a silken thread. This species may








feed on any part of the leaves, bud, or head of the plant, but usually prefers the buds of young plants, crevices between leaves of
-heading plants, and the lower surface of the older leaves.

The cabbage webworm is about one-half inch long w. hon grown, is dull grayish-yellow, and is marked with five brownish-purple stripes that run lengthwise of its body. The head is black and boars a Vshaped marking. This species foods under a protecting web and profors the buds of young plants, but may food on other parts of the plant.

The corn earworm may vary considerably in color but usually is dark brown, with grooeen, yellow, and black markings. This species usually foods on the bud and heads of the plant, tunneling into thoso pqrts as a rule. Full-grown corn oarworms are about l4 inches long.

Quvorms vary according to species as to color and markings,
but us ullya are stout, soft-bodied ctrpillars, from gray to brown to nei oly black, and sometimes spotted. or marked with stripes. They are about 1- inches long when full grcwn-. Cutworms either live in
the ground and cut off the stalks of plants, or live on the plant ana food on the buds, hoads, or loaves.

USE OF INSECTICIDES

Unfortunately, not all species of cabbage caterpillars can be controlled with the same insecticide. Materials that kill one species may not be very toxic to others, and certain insecticides useful during the prohoading period of plant growth, such as those containing arsenic and fluorine, should not be used during the heading period, on account of the harmful residue hazard. Rotonono-containing insecticides usually have proved most satisfactory for controlling the imported cabbagoworm and the diamondback moth during the heading period of cbbage growth; pyrethrum insect iLcides usually have proved most effective against the cabbage looper during this period, and combinations of rotenone and pyrothrum have beeoon effective against all these species. Pyrethrum insecticides, when used at the strength and rate recomendod in this circular, will not leave harmful residues on the market product. The corn oarworm and cutworns are not satisfactorily controlled by either rotenone or pyrothrum. These species
must be combated, therefore, with arsonical and fluorine compounds, which also are toxic to the other species of caterpillars mentioned
herein but should not be used during the plant heading period, for the reasons previously given.

The following recomrinondations are designed to provide for the control of caterpillars on cabbage without the use of rotonono-containing insocticidos during the existing wartine emergency. These re onondations are also designed to conserve pyrethrum and arsenic,











because the supplies of these materials are li:mitoed. Th adoQ tion of the practices given in these recommendations should give satisfactory control of caterpillars on cabbage during the preheading period of. this crop. They should also give a satisfactory control of those pests during the heading period of the crop unless the diamondback moth caterpillars are unusually abundant. In the latter event, the incorporation of nicotine in a pyrothrum dust or spray, as detailed later in this circular, should roduco infestations of this speciess to a worth-while extont.

In gencral, cabbage being grown in the extreme southorn-parts of the United States (the southern portions of Florida and Texa,) usually requires protection against caterpillars during all or the greater part of its growth. That grown in other parts of the South usually requires insecticidal treatment during all periods except the winter months. In certain parts of the last-mentioned areas, control measures may be necessary during mild winters (those during which wockly moan temperatures do not remain below about 600 F.) or may prove unnecessary during spring seasons following severe winters. It is recommonended that control measures be started as soon as 'the caterpillar population averages about one nworm" per plant or ite1n approximately 25 percent of the plants in a field show signs of rcent caterpillar feeding. Ln general, control measures are unnocssary- when weekly mean temperatures fall below about 500 F. in the fall, and should be resumed in the spring when wooeekly mean tomperaturds are consistently above about 600..


CONTROL DURING PLANT PEHAD rIN G PERIOD

Soil-inhabiting cutworris

If ca.tworms are present in the soil before 'the crop is planted, the'following poisoned bait should be broadcast on the soil surface late in the afternoon at the rate of about 25 pounds per acre:

Wheat bran - - --- 25 pounds
Sodi.um fluosilicate .-. -. - .- 1 pound
Water to moisten

Thde bran and poison should be thoroughly mixed while dry and enough water added to danmpon, but not wet, the mixture. This bait
also nay be used against cutworms after the plants are up, but to prdvont serious burning, care should be taken to see that no bait lodges in or against the plants. For use when plants are prosont, it is saferand more economical to substitute cryolite for the sodiim fluosilicate in the bait and to scatter the bait at the base of the plants at a rate of 10 to 15 pounds per acre per application. Scoral bait applications may prove nocoessary to reduce infestations satisfactorily.






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Caution.-The poisoned bait should be scattered thinly. SpecSprecautions should be taken to avoid leaving piles of bait on
the soil surface. Experience and careful observation have shown
that if the poisoned bait is prepared and applied properly, its use
will not present a hazard to domestic animals or wildlife.

Cabbage Caterpillars, Corn Earworm, and Climbing Cutworms

To prevent damage to young plants in the plant bed or in the
field and to reduce the possibilities of damage during the heading period, which is especially important under present conditions of
insecticide scarcity, either cryolite (natural or synthetic), calcium arsonato, paris green, or barium fluosilicato should be used at least
every 10 d~ys during the prohoading period of plant growth if the
catcrpialrs are present in dnamging numbers that is, an average
of more than about ono caterpillar per plant.

Dusts.--Cryolito should be diluted to contain not loss than 40
porcont of sodium fluoaluminato, which usvally moans that the undilutod cryolito is mixcd with approximat_,lr equal parts, by weight,
of any of the diluents mentioned later. Barium fluosilicato should
be used at about 75-percent strength, paris green at 10- to 15-porcont
strength, and calcium arsenate should be used undiluted, or at 75porcent strength if the brand being used causes plant injury when
used undiluted. Talc, pyrophyllite, sulfur, or other nonalkalino materials may be used to dilute cryolite and barium fluosilicato. Hydratod lmo should be used with paris green and calcium arsenate, but
not with cryolite or barium fluosilicate.

Sprays.--Cryolito, barium fluosilicato, and calcium arsenate
should b o used at the rate of 2 to 3 pounds to 50 gallons of water
(1 ounce to 1 gallon), and paris green should be used at the rate of one-half pound to 50 gallons of water (2 level teaspoonfuls to 1 gallon). Two pounds of hydrated limo should be used in each 50 gallons (2 level tablespoonfuls of lime to 1 gallon) of the paris
greoon spray, and be added to the calcium arsenato spray if the
brand used causes plant burning.

Supplonentry poisoned bait.-If applications of those arsonical or fluorine compounds do not provide entirely adequate control of the corn earworn or climbing cutworms, a bait composed of
10 percent of cryolite and 90 percent of corn mcral, by weight, mixed and. used dry, should be sprinkled into the buds of the plants at the
rate of about 25 pounds per acro just before the plants begin heading.

Procautionary prohoading trcatment.--To reduce the need for insecticides during the heading period, it is suggested that a thorough
application of one of the aforementionedo. arsenical or fluorine compounds be given cabbage plantings (except those that will head and be











harvested during relatively worm-free parloa-s) just befLore'tepas begin headinglp, even tUhoughi caterpillars ia~y not be abunant a th t ime. This is partic-idarly a~~cbeto spring planting thtnr mally would not require -notiieprotection Coring the spread period.

it is emphasized that treatments with arsenicals, or f lorino compound 'shou-Lle,. not be made d-uring the prohoadin6b poriod to Ulos hoadqd typos of cabbage intended for~ marl-oting with more than~ four loose oute-r leaves.

Wnrni_ "'.-Calcium -arson,,to, paris green, cryolito-1, and. barium
fluoilia~ ~r poionos ad sould be hzindled thcnrcr an stored whore chil'Lron, 'careless pz rsons, nc1d domestic animals cannot roac them. Especial care should be t, j,,rn in mir, in raNyng those in secticidos not to inhale excessive quintities. Woll-deosigned respiraters affording protcction to t)-,, -ntire, face should be used. whcnever. avi,71. ash the h-Lands or other (,x-coscd parts of tho body
thorouhly~ .fter working with theseo compo-unds. It is roponted that. these materials shouJ4 niot be rappliod tu-o cbbago aftcr tha, t portion of the patthat dF7 -to be makt.dor (cn m.rmOdC )L oxposc~d to~
vii.This moatns that cabbagec. to be maito ith foiur "w,,rtiaP loavs (toI t lea st twro-thirO.s loose fro- and surrounding hbc firm head>, should: not be treated with these manterials, after tho ea begins to foi (theo bud leaves begin to "fold" or "cup ovorllY_,whoh usually, occurs about 30 to 40 darys before hparvesting, normally begin. The materials should never be usedl within a bout 2 weeks of harvest and all "wrapper" 'lnav ,s, should be stripped from the firm ho':3 ,if arsenical or -fluorine compounds are usedt as ea last resort in cases of severe infestat ions after ca-)bbage begins to hea)d, It probably will be found that this strip-,-ing of the. loose loaves will not be a profitable commercial practice in most areas in the South. Cabbage to be marketed or c=,xjaodf i.ith nore, than four "wrapper" leavco. should not receive arsenical or fluorine applications after the normal. time for thinning or trarnsplau-ting.


0O9TROL1 DIRL7G FI~id\T-HFJD fTG PERICD

For the control of, the green-colored_ caterpillars on heading, cabbage under -present conditions, it is recorireindod that pyrothrum dusts or spnrays be used at least every 10 days throughout the period, if there is an average of '-.oro than one caterpillar per plant.

Pyrothrun dust s.-.-Pyrothr,,u- riay be used, in the f'orn of finely, grounOd pyrotirum, flowers in a Cdust or in a spray, or as extracts of these flowors incorporated& into dusts or usod directly in sprays. WThen used at comparable, pyrothrins, content (the active ingredients
of pyrothrun flowers), the so-cnlled "1impregnated" or "lcoatcd"l forms of dust which contain oil have proved slightly more effective than






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simple dust mixtures of ground pyrethrum and a diluent. For use against caterpillar populations consisting chiefly of the cabbage looper, or the imported cabbageorn, or the diamondback moth, an "imprognated" or "coated" dust containing 0.2 percent of total pyrethrins or a pyrothrum powder dust (ground pyrethrmm flowers) contamining 0.3 percent of total pyrethrins is recomacndod.

The "impregnatod" or "coated" pyrethrum dusts containing 0.2 percent of total pyrothrins may usually be purchased from dealers in- a form which is ready to apply. If those materials contain more than C.2 percent of total pyrethrins, however, they may be diluted to that strength by mixing with such nonalkaline diluents as talc, pyrophyllite, sulfur, or tobacco dust. For example, if an "imprognated" or "coated" dust contains 2.0 percent of total pyrethrins when purchiasc'. from the dealer, it should be diluted at the rate of 1 pound of this r;merial to 9 pounds of the diluent. The pyrcthrun powder dust (grcund pyrothrum flowers) may be purchased from dealers in a form which is roady to apply. If the powder dust contains more than 0.3 percent of total pyreturins, however, it may be dilute. to that strength by mixing with the sanc cliluents mentioned previously. For oxanple, if the pyrothruri pcwdor dust contains 0.9 percent of total pyrethrins it should be diluted at the rate of 1 pound of this material to 2 pounds of the diluent.

Dust mixtures prepared from finely ground pyrethrun flowers may be improved by the addition of 2 percent by weight of a light mineral oil (approximately SAE 10 specification) or by the addition of 1 percent Of thiocyanate (available in commercial preparations containing approximately equal parts of an oil base). If either of these .materials is added, the dust may be reduced to 0.2 percent of total pyrethrins content. The use of about 20 percent of sulfur (20 pounds of sulfur to 100 pounds of n-ixed dust) has been found to improve the effectiveness nd stability of pyrothrun dusts. Kaolin clays reduce the effectiveness of pyrcthrun dOists -nd should not be used as diluonts, especially under present conditions.

Pyrcthrun sprays.--Alc.holic or acetone extracts of pyrethrun in water or pyrothrum powders in suspension in wator may be used as sprays. The extracts should( be diluted anc used according to the manufatcturor's directions. Sprays consisting of pyrothrum powder and water should contain not less than 0.006 percent of total pyrothrins. For eaPmple, a high grade, fresh powder (grounC pyrethrun flowers) containing about 0.9 percent of total pyrethrins should be used at the rate of 3 pounds to 50 gallons of water (1 ounce to 1 gallon)- It usually will be found desirable to add a nonalkaline spreading or sticking agent such as a mild soap, a miscible or sulfonated oil, or a proprietary compound, designed especially for this purpose. Cake soap n y be used at the rate of about 2 pounds to 50 gallons of spray and the liquid materials, in general, at the rate of 1 part to 400











parts of.spray. The use of reading agents has the disnAvantage of rein ov im- '. s ome. or, all of th-- wa:,"'t )_Lnom from cabbage leaves,' there by aff acting t'Pe -10, p!_pn-, scrjlr t I T-) 0 S C n.),!Sing them
to be moro susceptible to dCzia-Cc by low toT:,pcr-).t-arc,:-Vs e of.nicotino !kainst 111oth.-If c,- torpillnxs of
tho-di=fjP 1b,' .(-,1_ %ioth arc cLFpocir,,_'].y niz.vro-ns, or if tho.history of the locn,11-1:3., or crop is such, th,-),t a h ea n f C, s ta t i C) L .r is S, 0 0 clos is cxpcctcd, -it is suggoctt, t._'1rt nlcotinc bo aeLdQcl to tho pyrothrizri Aast or spray. ITicotino,* citKcr the "froc" or tho "fixod"
a6'infcstdticns of dianondbc-,ck moth or', has boon fcund to.rodu
caterpilic.rs to a worth-whi"'o, clor pro i, nt cor 11t-lo-ns, but
is of litt-o val uo in the co-1,trol of'tho othor J.T lp.ortanl- spocics of cabbtigo -)Illarc# The fr3c -L-r1-r:aof nir.otinc r4lso be offoctivo ;F 4")J-ist zrmhiflts, or plant .. Lco$ th-t rin,,,- -cc nr -,=.'J. A:,)out
2 percent of nicotine should be tto -a ryrcthruT.i d,.-Lo-1% Approximatoly (1,T1 to 0.1 percent of nicotine (1 part of S'ulf.-Ito
to 400 prxts of ,rntcr,- or 2 to of a 1 -pcrccnt "fi- :1xill nicotine obi.dor 'to 50 9fillors of ) -,-.tc)r) bc t) a pyrothrum spra;kr, ho niectino r.v,y 11 6 rpi)" sr_-)7LratcJ v f r,)T.a '-hc pyrothrum if d )sir,)d, but shoulA not be CIC c1l C..Lt-..-- f --) r Cq. t
brPillar control. No li;-1c bo Li%,.,Lvcd in tho of
nicotine if cryclito has rocont.l.- I r boon usod, or if citzicr cryolito or pyrothrun are to be used in',tllo near futvro.

Caution.-Soi.ic obsorwntions Inclicr-itp that nntorinls such as
nicotine, anOL oils, which cause incror sc(7. toxi--ity of
pyrothru.1-contziinlng dust miXturos, nay also ho.vc a dot rior,- ting effect on such mixtures in prolongorl stor,),ge. It is not a0visablo, therefore, to buy or'to pr,7 parc n gr' eater q:anntit77" of thcso 'dust mixtures than is likely to be needed in 1943, rogarftloss of the availability of the riatorials.

Use of other insecticides anO_ latind picking. --rhus far no ontirolir satisfactory, roadily-avaiic Uo sl;Lbstituto for pyrothrum. an rotonono in the control of.cabbago cn.tcrpill,, rs has bocn found. Tho search for now insecticides rmrl riothods of iriproving known ones is continuing.

Phonothiazino, n conpr rntivoly now conpoiLcl, is sufficiently toxicto cab ragc cpatorpillars to 'be of value in cnso pyrcthruri is not availriblo. This material riVr be used nx ,. O.ust -,,t not loss than 20'porcont strength, dilutoc! with talc,,clay, pyrophyllitc, or other
nonalkalino natorials. For use as a spray$ phonothinzino shoulft be used rt the rate of 2, to 3 pouliOs'por 50 -,-,.llons of wrvbor (1 ounce to 1 gallon) with a proacling, and sticking, n-on t.

If usca rogulprly once a ifook, a rolativc17 strong sor;p spray (I poun(I of a nilcl loundry sonp to 5 gallons of wator) will-,-ivc






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faily atiasfactory results, but should not be used near or during
beowfreazing temperatures.

For .small plantings, especially home gardens, hand removal of c aepillars is of val~ue.


METHODS OF USnhTG DUSTS AM SPRAYS

TDusts.-.-For best reults, insecticidal dusts should be applied whdon the -air is ci.1m, or nearly so, when tilo. atmos-ohoc is so heavy as to bho -._ *ho- du_-st near the ground, -and whcon the plants r slightly moist writh CLew, The pridafter s-unset iand for scvernl hours thereaftor u lyis a La 1.orabjle time cf dnay for dusting. Arsonicoa and flnorin-,moud a' s-o may, bc -T-oiod to advantage during the early morning, .-,-rothr-urn, however, is more effective generally whena the planted C y or only slmt2yrolst. Consequently, the onrly
morning ors ar nxo a f-!ou-l time fPr app",ying this insecticide
~ ocus ~;oplzi~ ic -,k o bco drc: .ux.od with dew at. that time.
Dust shci..Id b_- axT'r2.c Lt zate rangin!, .rom I0 to 25 pounds per acre p02 a)plidCr. !on (,aoout 2 ouuan -s to rkO feeot of row), depending on the o iz o of pLLt 3, the spacing of the rowrs, and the dilution of the isocticido.

_Sprnys.--Sprays may be ---;plied at any time of day, but the wind should aot be so high as to interfere with thorough coverage and tondcer 2j-I.-nts should not be spro, od with strong soap solutions while in 0diroc _snligh~t duzring- 11ot weter prays should be used at a rate of 50 to 100 -allons per acro, per application (about 2 quarts to 50 feet of ro-w),

Dusting annd spraying oq~aipmont sho-uld be adjusted so as to give thorough 'covornge of the plants, T-:d. such equip-ment should be kept in goL-d. mechnnica.l cceriition, especially now that machinery is difficul .toreplae. Ihon aLpplying dusts to dry plants during slightly wii:ndzr vowethor, especia.iy duists containing nicotine, the use of a cloth apron or trailer that oxtonfs for.10, :to 20 foeot back of. thp dlust miachineri us-r:-lly will 'be of value. The use of cloth bags for applying dusts aacl of wnterim;- cans, or sinilnar containers, for applyin.g spray),,s is not advisCLI as those methorls usually rosult in rellatively poor caterpillar control andl in waste of -insecticides.

Insecticideo materials, especially those containing pyrethrum,1 which deteriorates relativeroy rapidly, should be used as soon as practicable after being Y.,ixed.












CULTURAL CONTROL ME"ASUJS

To reduce caterpillar C-om-nage and the need for insecticides,
cabbage should be grown whenever possible during periods when caterpillars usually are least abundant; the crop should not be planted
near caterpillar-infested older plantings; the rows should be of
uniform width in order to permit most effective adjustment of spraying and dusting equipment; the plants should be uniformly spaced
along the row to prevent crow ing and consequent poor distribution
of insecticides; the heads should be cut as soon as roady for market
or hom uso; and crop remains should be plowed under or otherwise
disposed of as soon as harvesting is complotod.

Caterpillar-infested plant beds should be poisonod with the
insecticides discussed earlier in this circular before the plants are pulled, and an infested field planting should not be thinned
before the described control measures are used. Plants with injured or destroyed buds should not be transplanted or obe loft in
the row during thinning operations.

Sufficient sooeed should be used to insure a goo. plant stand without a waste of seed. Cabbago should be given good cultural. care, nd fungicidos and fertilizers should be applied to keep the plants in a
healthy condition.


W HERE INSECTI0IDES MAY BE 03TAI.ED

Information regarding the purchase of the materials mentioned
in this circular usually may be obtained! from local dealers in agricultural supplies, sooeedsmen, goncral stores, and drug stores, or
through the county agricultural agent, State agricultural experiment
station, State department of agriculture, or ,the Bureau of Entomology
and Plant Quarantine, Agricultural Research Administration, United
States Departoment of Agriculture.


SUI-LARY

Recommendations are given for the use of available insecticides
and other control measures for_ c control of cabbage caterpillars
under emergency conditions-re-sulting from the war. Rotenone-contain'ing insecticides are not available for use on cabbage. The only satinactory substitute for rotonone insecticides for use on cabbage
after, the heads begin to form are those containing the active principlos of pyrethrum. It is reconuiendnod that dust mixtures contain at least- 0.2 percent of pyrethrins. If a simple mixture of ground
pyrethrum flowers and an inert diluent is used, it should contain
0.3 percent of pyrethrins.



K









TLo avoiO- a harmflnJ. residue hazard the arsenical or fluorine
compounds should. no)t ',e uoed on any part of' the ca:'ba);,e plant that is to be nireM.Tis mear's that cabbage intended for retg
as U. S. Grade N~o. 1 (which c2.lows fovr loose outer lea.-res) should not be poisoned with these materi-,-a's after the hea-6s begin to form or the leaves start Itcupping,1' tha,-t isp when the leav-es in the center Of the plant cease to spread out
Th'uing tha preheacling period cf c,-*bbagc growth, dusts or sprays, containi.-.6 cryolitep calcia arsenate, paris ggreen, or bnriun f'luo5i2at~shou].d be usoed. If applications of tilose areenIcals, or
flxuorirn cr--poiri-ds do not provide zadequate control for the cor-n errworm or erbintLa cutvorm, a -Do iconie bait cons isting of' crj'7olIite and corr. ms12 ould -.) sprinkled. into the b-ads of' the plants Just bcfore t h c b i h L,- 'Iing.

Al*-ti*ons of insocticidles should! b-3 made at 1O-d..y, intervals b I n aing .a~ r. oor.'.s tllero iG a-.)Iroy,:!:.at,,ly one "wr pe plan-Mt or whon -p-proxiraately 25 percent of -the plants in a field show signs of' catOrn-Illar elhg

Control of cabbai-e caterpillars can be aided by the destruction of cropo remnants as soon as harvestin,; is completed; by growing. cabb'o'e whenever possible during periods when the caterpillars aro lcore abiindant; and by planting new- cabbage as far as possible from older cator-pillar-infostoci cabbage.




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PW UNIVERSITY OF FLORIDA





0922469


















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