Rkhard l. Baldwin F2rrn Advisor 52 North California Street Ventura, California

AVO(ADO

WALTER EBELING

ROY J. PENCE

E.STS

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LarvCl qf the o~~iVO,~ou$:IoopeF (see, p.20}, showi~gthecharQcter"

,isticlooping of tHe body when the in~e,ct is crawling. (X 2} , , , .

. AVOCADO PESTS •• • like the one in.thepictu:re ahove •.. are 011 theri~ein'Cali- ,'. fornra. Others ar~ less, important than, they used to Jje,hutnew, pests are' . , . replacing them. "Latest ~dings. show" that', the '. best ',control' program, is ,to spray as little, as pqssiple except Wh~Te. uTge1!-tlylteeded: Youniayd~tl"qy the, natural' balancebetwe~npests and l;h~ir enetrlies;aud" ~lso ,enc,ourage new!l!ld moreha.rmfulp~sts. If you have to spray, use an acarlcide (mite-killer) along' with your insect'jc~(le.' , "

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THIS CIRC~LAR presents up-to"date information o~ the' s~atus and control of pests' , on California avocados. It tells yo~how to identify , them in the field; what

. new pests to watch, andwhat pests ~re of onlyminorimportatlce. Consnlt the back cover for an a:lph~beticallist of pests described in this circular. The CHECK LIST in the center of the circUlar summarizes control informa- ' tion on all pests of economic importance. '

THE AUTHORS:

W~lter Ebeling is Associate, Prof~ssor of Entomology and Entoinologist in the Experiment Station, Los Angeles. ' .

Roy J. Pence is· Principal Laboratory Techriiciim in the Department of Eqlo.Ylology,LosAngeles. ~ , " ' .

MAy,'1953

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"'~VOCADOS .. are ·.st~n, a. ",youIlg" crop'. in ; C~Iif~rllia,.C°rllm.ereialpro~uctioriwas )l.O! seriously consiH~red llntill910, anQ,

.. as'late·as1924th~·production for the . \'yea,r Was Qnly130 tp.nsiIl,the state. AEI.

" ~Js .usuallythe'case wheria fruit iPQustry is ll,e:w1yestahlishetl ina> region; th.ere

. foUowe'a., a period of rellitivefreedom' " ·.Jroin serious pests. Theh~iefwa:so£ten

"e:lCpressedipthe early,dayso£ the in~. . , . 'dustiyiIi. CaHfQrnia'tha,t th¢avocado ;0£ soip.~pestd~ sh~tply lilIl.ited by eli- . ,tieeand its fiuit are inhetently inmnine" mate. ' . .'. " .

. . tp.seriiJUs :attackhy msectpests. . . .;' Over a third. of, the))l'iginal University' 'OptilllismlIkethisw:asnotjll!,tipedhy of California hUlle~in on avoca~o pests

l:heeiJq)etienceinM~xicQ, Centrl;llAmer~ . (1935) was devoted to the latania scale/ .icai·' and South Ame:ri<ia, where theavo~ , then\known to he the'most importazjt cado:is~nativeJrJiit .. Not bas it Oeel!' pest of the avocado; Today,apparent}y jus~ified. byl/iter experience in Cali,fQr- thrQugh,the"effectiye w<;>rk of'natural.

... · ... ··,·.l!ia.l\1;any insects, hQth nativealld intro- enemies,this insectis a JIlmorpest. A,:tti­.,duced, nowa~ack the avocado tree and ficialcontr<;>l is no longerpracticed;'10n'

;.its'ftUil;in the~tate. Some. of thes~ll:re the other hand, the greenhous~thrijJ~ annJjal pests incertaiil localities where treatt!daS' a minor pest in 1935-,-:and ,the

jheclimate . favors their develoPI11ent.,' six-spotted mite, which was not even .Others'a'tespOJ;,ailic' in their a,tta,cks,mentioneo, are now the most inipor~ant • ·being. 'lilerious. o~ly .in certain localities pests of the avocado in California.- Avo­

Il;iidln cefta:inyears,whenenvironmelitalcado pests, we see, have dramatically ',' '. factoIs .cOJ;nbine to increa,se' tlJ.eir pot>uhi~ .shifted in. impottllIlceover the. past"few 'tiollS, to-ec,(momically iIIlPortantlevels; , ,yearlil. Inadd,ition, ~ew pestspeciesh:av~;,

'. "Fortunately. for th~ Galifo~niagrQwer, cOme' along; there. is ,new biQlogical' in-1l;v?cado<pests in <this state, ~re in, the . fOl'nl1ition op several pests; above all,

,'rriainneitherasseriousll?r as wide- JIlanyn~w insectictdes apd acaricide's s.pre,~9,aspe~tsof m9'lilt other subtropical' (mite-kille17s) have come onthemar{cet, '£ruit, crops. Likewise they are more' easily , resulting in improved control measures, coritrolleiL Natural\enemiesplay an i1n-: for most avocado pesrs. This ei~cularh~s :poItant role in keeping down: pest po.pula~ been ,writtentQluing all fuisnew i~£or-,

. ticms,:(s,ee page 4) "anQ..thedistrihution mtJti6nto the avocado grower.' -, "',' . .,',.. ' , " ,-. > r ," • •

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;~~'~~~;f}i~li~~if~'~4i(:~~,! .. ~.1.".;l;}}~~1~t~~~~~'~~~J~1*~~~~~i;sj~IT;:~'ZiJ?J~:~'~~r0~f~~:~,";i:');;""i j~;tii:~'{t':';\':,J!':,;,;;i~!7!~;~~~: " ., "<~~_,,.:', ,','Z"/ .~."' '\:,:",:.'\'.~ .• :>~\~

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~pott,edmif~tltiriate~$'t6becotiifi,ased~": ~diISpest.d9Iiot,appij'iJl~e()tiCi~~I'!: e:x;cept: ',;i;

, \\'liereurgeIJ,tly;!needed,~nd~lways . add ' ~n,effecth(e'! ac,a~icide~Inite-killerlfor ~mite contrQI. ,.' :', ~, '. ' .... , .... , AntS: ~ie,knowh' 1;6 interfere with the

,~'adiviU~s{6f$ehatuJialenemiesoflliost~ .• ' !pel'!ts,~IJ, av()cl!,doslpai1:icula~ly'~Of;thei3ix- . ','

.' spottedmite;tb,eme~lybug, and thl:} .J>o#.' ' " , ',' ,',' ,',scale.AriicO;ntr()lplaysani~portanfp1"ij:t , "Many ay~~adb pest~hk~~~~tJj~~i'eIieiiies " in yom:pe.stcontrofprogram.' .'.

l\':hicn control" their' p()p~lati6~s/The',CA\UTIQNn labmia scale and the lqng~tidIedin,ealy- . .... .... .", ,,' . . . .... .

, bug, onceimport~tpests 6~th~,ayoc~do · .... Mo$t.in$~c'i~id .. sa .. epoi$c;~:cJU$·, ", ·'hi'Galifornia, haye!Jince:b,eeiU'edlIc~dto . ~nd' ~hOuI~'~e;handleCl.withcau~ '.' . '" .. mhlOt imp~:ll:tance:ny tl1e·Work,of~sucntic,n •. ' All,.ral>~is :ouinsectici<le packages 1 c.'

. enemies. Y ourpestc9ntn)lp'rogtarrlnlusf "'or container& shoUld he read ~nd itin:e~ include wayI'! imd "means of pfotecting e~uti()n~ arepriittedon the!!e labels they

,t}uim. Do nOtspra'Yultles.~surg~ntzr .shoul.dbe f{)llowe9:carefully. Avoid body need/ed.Untimely spraying ca.n Kill off. c()ntaetwith: insecticides. and,donoti!},

··mitllral enemies faster,tlilinthe, pests ' ka1~ dUst 'orfumes from them: Liquid . , themse1ves,aJ}d destroy J;henaiural bal- conqentrates !Jpilled on the !Jkin or dot4~1'! . anceof :lnsecdifewhich is still the most .. ~reextremelycdangerous. n thisoc~urs, .. ·.'· .important control factorforthe:m:ajority . imrnediattlly.remoye cIQthingandbat~e~ 6f avocado, pests. Again, . such spraying thoroughly with plenty of. soap and

.·:can'introduce new, immune pel'!ts,whose water.' , . .... ..' . . ownnatutal eneI!lies may have been Parathiohis,i1ighIYfoxic t9hu~ swept away with thee~rlier pests.· . manbeing$.Reaa.instnictionsJornse " Apparently this iswhathash~ppen.ed ~s printed: on lahekA dust- and vapor- ;

.' with thesix~spotted mite-now a,thteaten- . type respirator,' sh9uldbe used to avoid .' ing pest on avocados. The use of insecti-inhaIihg. the! materia1..The use of para-cides has preserved iliel'!e mites while de" ", thi91l- is.still experimental in,avopado pest·

. "strojing' their naturalenemies,and in-, contfot.,Wh.e;r,everpossillle, itshQuldJle teilsified th~ir damage.' Espepially 'in the' 'applied'· by . an experienced ~on1inf'Tcial immediate coaetal areas where, the six" op.er~tor. . , .

THE CENTER SECTION .... ; ·of this circular presents;·, in brief, a: fi~t of the avocado. pests ,described, together., '

wjth therec~mmendedcontrot me~sures. This. Check Chart is printedori durable

paperstoc/<, and may be, removed from the circular and'tackec;Ffciawakfor ~Uicl(; '.

a~~ eosy ref~rence.For more defailedinfortn~tiOnQ~outide,r'ltifkati0i'! cindcoiltro'r '

ofeachpe,st, fead the individ~al descriptions inthe~kcvlcir.

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SI}C .. SPOTT~D MITE , Altho.ugh: th~six-sPo.tted mite, Eotet.:"

ranychus sexmaculatus (Riley), nas been a' pest o.f citrus in' theimmediateco.astal areas o.f so.uthernCalifornia fo.r many years, it was,no.t noticedonavo.cados until 1947. ,ltnevetlleeaine abundant until the, spring ,of 1950, and throughout' that yeat it: caused sevetedatilage/J;ly de; fo.liatingtreesincerfain o.rchards in' the

'Carlsbad andEIicinitas'areaso.f San six.spofi~dnrlt~ pro.b'lemwo.uld , be Diego Co.unty. 'fhesix-spo.ttedmiteagain greatlyalle,riated,'fo.rtne natllraJbalance" caused~o.me seriousdllmag~,ln 1951,' but between Jhe utites and ,ilitiir·iirsect ene­

, Was no.t' so ,abundant, as during the pre- 'mies ,would .tJ1en~o.t he, destro.yed. ' , ,', Vio.Usyear.Itremains to. be seen whethoc, ,Appearance. The adult mites (fig; , , " thiB:mitewinc()n~inue tobeariimp6rtant 1) are about % \'i o.fan inch lo.ng, o.val in,,"

"'pest ,of a:vocado.i!!o.i' whether in ilie future 'shape,', and sO. smail, that they can hardly ~its, appearlUlce wilL be 'sPo.radic ahd he seen with the unaided eye. They are.' " clo.sely deperideIJ.t oh favo.rabie climatic generally a: lemon yellow inco.Io.r, the' co.nditio.ns.," ' "majo.rityhavingblackish SPo.ts usually

,Co.nsicl,erable eviden¢e sho.WS that the gro.upedo.r co.alesced illto. as many as six: ,six-spotted mite hils heco.meapest on 'areas. On so.me there are fewer blackish' / avo.cados as a result.o.f the eliminatio.n o.f areas while o.n o.thers there may be no.n~{ natural enl(mies caused by the wide-D.velopmerit.Thetiny, glo.bular; spread use o.fDDT;in,the control,o.fthe pearly eggs, ,which bear a'sialk at their

"greenho.usethrips in recent years; 'Itili apex (fig. I), arefo.und in areas where the likely 'that ,if' insectidde' treauhents {o.:,: miteS,are feedi~gand,may be ,laid o.n,the other '.pestsco.l).ldbeavoided" :even' at ,surface of the leaf o.r attached to. the deli­

" thensl<: -,0,£ 'So.me lo.SS ,fro.m the Pl3Sts, the' qatewebbing witlljvhi~h, the mit~s 'covet - ' '/ ", ' such areas. Ina perio.d o.f 10 to. 20 days

the females may lay, 25 to. 40 eggs. These, require fro.m 5 days to3weeksto.hatch, depending'o.n temperature. Fro.m 8 to 12 days ate required fo.r th~ mites to. r~ach: maturity during theSUIri,mer mo.nths.

Injury/The damage these mites cause to' citrus leaves is well kno.wn. The mites

", o.ccur inco.Io.nies o.n·thelo.wersurface o.f ,the le~f,~ausing a co.ncavity with a, co.rre~ "sPo.ndirlg bulge o.f,the lea,f.on tlleupper surface, which beco.mes yeno.~; On avo.~ cadcdeavesthe siJC-sPo.itedmites also.at" taCk o.nlythelo.wer surface o.fth~ leaf" along the ,midrib 'and larger, veins (:6'g..; 2). The:infested areas beco.me bro.wnish '

, ill co.lo.r, bot dono.tbeco.m,e depressed as , ihey do. ,o.n citrus leaves, fo.r, the avocadO' , biaf is to.o. rigid. The :mdre seVere inIesta> -" tions cause :the leaves ,to. drop. Oithe principal avocado. varieties, Anaheiin;

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N~9al;"Wurtz,ailifC~rhb~d~pp.e~r tQBeSulphenone:4Qper eeIit ~¢ttabJe powder. ; ·tlie·mo&t.sey~relyattaCked .. ·• . ... ·.i .. ; .,: " 'at2'pounds {or the. 25 per .elmt emulsi-'

," . Control. The mHessh()uld@ireate~,' fiablesolution at3 pints}. to 190' gallons; i:w~enth~J~~~ 's~~tomsof injury begill' The sprays ~houldhe.thoroug~ly applied, ,toappeat, a.hQ,be£9Te.setibiIs injury to and since the' six-spotted': mites occur

. the . tree$hal!occurred.FoIto'~ing a eOn- • only op;the underisideso.fthe l~aves.itis ;" /Ji~~()u.~ ilecr,ease;thi'oughou:t the,late~allim:portani tospraythejnsid6 .q£ the tree~ ... :

j.,,>,' and winter"moIiths,.themi~es.areJikelyto The:E!'ddition ()fanefiective spreader. iK" .' ··;:·~.',fncrease jiI.~uinhers·dut'iirg the:spting.· :T~cOInmended, for,otherwiseit~s hnpos~.

Tteatmentswitlieffe.ctive acaricides. ap- sible tQ wet the under I:!ides of the1eaves. ;' plied at tha.t time have. genera:lly con-. A 3pet-cent Axaniitedu.$thasshown trolled the mites for an. entire seasonopromiseinlimited. Uials when applied

Three new'. ac~ricidesare reCOm- with power dusters of adequate capacity; mended for use in:the contro~of the six- . Wettable sulfur has been ll.sed cominer­spotted '. mite: .kamite, Ovotran, and . cia,ll:yat 5,·pounds to lOQgalloils with f'l:1it .Sulphenone. They are recommended as success. hut even at thishigli·dm;~ge.itis/·

. sprays in thefoUowing concentrations: inf~riorto the above:materials... . Aramite 15 per cent. wettable powder at 'The systemic organic phosphat", in..' 2 pounds, the 25 percfmtwettable powder secticide known. as .Systox has been used at 1% pounds (or the 25 per cent emulsi. •. experiment\llly in limited trials. It shows fiablesolution at 1% pints) to. 100 gal- ,considerable pro~is~ whenappliedas a 1pns; Oyottan 50 per cent wettable powder spray or whenpilinted' on the. tl'llnksof '80 pound (or the 25 per cent emulsifiable thetrees at the rate offrom 2 to. 4 ounces; solution at2pints) to 100gallcJDs; and of the 32 per cent emu~sifiablec'oncen~~ate

per tree, depending orithe siz,eof the tree. When painted onthe trunk,fhe insecticide reaches the mites through the sap stream as the pests feed on the foliage. It also controls the gteenhousethrips in this manner. Possible toxic hazards of this in, secticide have not been fully evaluated; consequently its ,use at present should be confined to nonbearing trees or nursery stock.

The' new acaricide known as Com­pound 338 appears to be very promising against the six-spotted mite in prelimi­nary expyriments.

Ants are known to interfere with the activity of the natural enemies of mites, and ant control is recommended to aid in combating the six-spotted mite as well as

,the majority of other mite and insect species that are pests of avocados. The ' writers have had excellent results in. ant control with a . slurry of about 2 pounds of 50 percent wettable chlordane powder

. to a gallon of water. This is applied to the trunks ofthe ~vocadotrees, by means of a paint brush, ina band4 inches wide. Ants must crawl over, the chlordane in climbing the tree. However, if any of the lower limbs should touch the ground they either must be cut backot chlordane dust or spray must be appIledat the point of contact with the ground. When the chlor­dane is appHed in this way the ground irrigation sprinklers do' not' remove enough residue to reduce its effectiveness. Observe precautions in the use of this material as indicated on page 4.

AVOCADO B.ROWNMITE The avocado brown mite, Paratetra­

nychuscoiti McGregor, has been known to infest avocado trees in California for over two decades. Severe infestations may Cause considerable defoliation. Occasion­ally, treatments are applied for the con­trol of this mite.

Appearance. The avocado brown mite (fig. 3) is approximately the same as the six-spotted mite in size and shape, but is predominantly dark brown.

Fig.3.'"'-'Avocado bro~n mite. leff~ adult fe­male;center,st~lkedeggs; right, adult male. (><29)

The webs are very delicate and may be invisible to the unaided eye, but exami­nation of> the, upper leaf'surface, with binoculars, will reveal considerable web­bing, especially in the region of the mid­rib and over depressed areas. However, the webbing may be described as light in comparison with many spider mite spe­CIes;

Development. The globular, amber­colored eggs (fig. 3) are stalked, like those of the six-spotted mite. They are laid first along the midrib but are later found distributed quite generally over the upper leaf surface. There may be tw() complete generations per month during the warmer periods of the year.

Injury. The mites are found on the upper sides of the leaves, at first congre­gated along the midrib, then along the smaller veins, or even entirely over the

. upper leaf surfaces in heavy infestations. The, area along the midrib, and finally aloug thesmaller veins, becomes brown­ish. In!iddition to the typical discolor a­tion of the leaf, an avocado brown mite infestation is characterized by the myri­ads oj whitish eggs and cast skins of the mites.

The destruction of chlorophyll no doubt reduces the value of the leaf to the tree~ The green color refurns if the mites are controlled, otherwise the leaf may drop if themite population is very heavy.

It appears that this mite does not cause so much damage as might be expected when compared with' the severe defolia­tion that can oCCUl; from much lighter in­festation;; of the six-spotted mite. Some

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groWers in r~~~n~ye~rshav~9iscontiQued :V~ntcii~,:-arid Santa D<lUJ'iI,ntl' "'J".,''''''''.' .tieatmentslol' theiavocado. brownniite, This.:mi1:ei~k.i1~Wn' as pamj~etl·a1iwchU.:~; .eve:p. when it is present in considerable pZa:cani AMc~reior.lt ~ numbers, yet have seldom suffered eco-'generally distrib1ft~' . . ", ,"'tI'''UII''

'nomically important da,wa.ge .. Sevt:~e. in- throughout sOllfhern California. It also festatiphs, if present, are likely 16 ,odciItfeeas'9Hpampb.or,cqtonea~ter, .crP~ess,· only on trees mtheborderrows,presum·e~calyptu:s;. lQqu~t, oak;.:pyra~antha;·: ably becaiIse the r~ad dustacclin).uli!,iing ~ycamore,toy{m:, walnut,;indWillow.lt '

'onsuchtre~s isdj'ltiimentalto natural 5.s re:p,ottedt()he~seriolls:pesto£loqua{s' 'enemies.,' . . . . in th~ Sa.nFrapcisco Bay area. .'

Control. The llvocadci brown mittds., 'The,platani #te£eedsc;>nidleupper . espeCially well c.ontrolled' willisulfut,sutface,sofiivoclldo, leavesandcaus~sa .'

. which is most economically applied 'as. a brownish 'disc6i<>ration ·simila,r. tothaf dust. From y.,·'to%pound oYsiIlfurper' whichis~qausedpythe related, avocado tree'is sufficient,.dependmg .0Jlthe<size . brown .mite.:This . mite .appears. to ,be .. of tile tree. Sulfuri~onlyeffectiveat tem-under satisfactory natuial controlatpn~s~ p~raturesabove70° F. Wettable sul~ur " ent, 1)ut should he regardedas~!lpotenti#l at 2 pounds tei 100. gallons ~s alse;> used . p~stolthe. avocado. . " , in'brown mite control,Qrmaypeadded to DDT us.ed for thecontroloHhe green~ h!luse thrips. However, severe injury to

. llie foliageandfruit_may,result in areas removed from the coa.st, such as Vista, at temperaturesa.round 850 F ..

PLATANI.NUTI Durirtgthe past year a species of mite

not previously recorded from .avocado I hIlS been foundonlliishostin San. Diego,

. P4LLlD NUTE A species of mite, Tydeus ca,lijomZcl£s'

(Banks), has becQmeTa.therilxtensively distrib:utedontlit: avpcado, in recent ye.ars·, and is verY Ilbundant iIi SQIQ,e ~rchards-,.

" . It occurs On' the' undefsides of lellves, is,,·. whit~s,h. in. color,slightly larger thanllie. s'ix-sp(ittedIllik,but has no black spots; , (fig .. 4). Nevertlil(less, it . js < commonly mistaken for the .si:l\:-spottedniite. . ,

T . . calijornic:us is closelyrel~ted to' some species that are: predators, but on avocado it has.never beeriseen'feedi~g oh.

"other mites' or insects. Large nu:rp.ber~ '. <mayhe seen onJeaveswhl(re,tliere is:noth­

hig on which the mites coiIldfeed.but th~ . leave.s themselves. No injurious leaf sytllp-t.oms have been associated. with thi~' sP~~'.' .. ' ..... , cies, however"andexperiments are now . unde~ way t'o determine 'Whether llie mites

'may havelln insidious .. effect thatc(.>uld, . ove~ an extended period, gradually deh

vitalize the tree without producing: acute .. sym,ptoms.

'ROAD MITE ;., i. - .

This species" known as,Hemita7;sene~' mus latus (B.a~ks), has heen·£o,tilla llt~ tacking. the tips of . avocado seedlipgs in greenhouses, . causirtg a' ',cha:racteristib crinkling and dwarfing af terDlirultf.oli~

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age (fig. 5). Since avocado seedlings are ordinarily grown outdoors, this pestis not of general··interest. Where seedlings are forced in greenhouses or where tip grafting is practiced, however, the symp­toms of injury caused by this mite should be recognized. The broad mite may be controlled by repeated applications of sulfur dust.

AVOCADO BUD MITE These tiny mites, known asEpitimerus

myersi Keifer, are even smaller than the, preceding species and are invisible to the unaided eye. They. are narrow and elongate and have only two pairs of legs as compared with the four pairs of the spider. mites. ,They were first found on avocado in 1938. They appear to he quite widely distributed throughout the avo- ,

. cado gro.wing ,area in ,California. The mites' can bemo'streadily found, under the "buttons" of the fruits, a~d the writ­ers have found as many as 186 in one such location (fig. 6). Despite their abundance at times, there is no evidence as yet that the mites cause appreciable injury of any kind.

SNOWY TREE CRICKET The green tWigs of. avocado trees are

occasionally injured by the egg laying punctures (fig. 7) of the snowy free cricket, Oecanthus niveus (De Geer). If the infestation is sufficiently severe some small twigs maybe killed,but apparently no damage of' economic, importance has ever been observed on avocados. Among the other subtropical fruit crops, these in­sects have been· found attacking cheri­moya trees, and on persimmon trees they are known to bea carrier of a disease causing fungus that, attacks the twigs.

Fig. 5;-Top: left, normal foliage of an avo­cado te'rminal; right, dwarfed and crinkled foliage of a terminal infested with broad mite.

'(x O.55) .. Fig. 6.-Centen a colony of avocado bud mites under the "button" of an avocado. A, adults;E, eggs. (x 13.2). Fig. 7.-Bottom: eggs ofthe snowy tree cricket embedded in an avocado twig. (x 35)

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.. ' GRE~H()USETHRIP5 "50ttt 9P~perC{)nlQrthefrui(ins~meor.' The greenhouse thrips, Helinthrips .c.h,ardl'}har~ .. €??Ul~~Sc~rr~f:l~: ~j~aGOJh

haemorrhoidtilis (Bouche), is widely dis- . ,se~q~en.tl~~lnmarkl!tvatQ.~;: ,'" .' '.', .... :tx:ibuted, in tropic III ·IlD~:. subtropical 're~ . ,H~f":;Clnd.v~de~~d' 5u5~eptibiUty~ ~ionsand, . itlgreellhouses, in teplperat~~ther/~4bttop~~~L' fruit$ attacked> lirt') regions. III Californill lind Floridait,oc- '. cltrus,gf,pe, Inango,saRot~i'cherimoya,

· curs?(ItdoOrsonavocado, c~tx:us, 'and ,and g~a!,a.AIl1011g,(n:naIlleI}Jalpla;nt~, . ttiany otherposts.Jn Galifoniia th~ green" :hefa.tlssa;~()~e;llrbtl~u~"v~~urnJl%'~~Il~;;

'. ,.· •• ·.·,.~Quse thr~ps hild been known to occur on •.. lCe,. ,mlUl4evdla;.:f)J{)h~!1a;,e~g~nia,.IIlYI11~;, .. ,avocados for many years, but wasenn- ,llzalea;~oJl¥ll1Us;'Nbl>erfi~"cypress, "sidered as one of tlie minor pests~ Within'" eucalyptJls,tmd HlflsembrY~Ilth~lrit'lmare.

'the last decade,howe"er, . it has; rapidly, especla~Y'~everelyi;lttacJied.Jll,fested· Q~- '.,

·increased,the severity'o£ its' attacks .. ~x. .?aIll~nt~~>gro~ingn~arayOcaqoP1.ant" ,cept during years follpwhlg winter!!, o£~Il,gs!!hould b~rY:(ll:ove4.gQ'tha.t they'~ilI " · .~xceptionallY low. tewperi~tures;. ,··th~. )1otbt! as?urceo~. i?f~$tation!rh~Slllt1'! greenho~se thr!P!!pbPulation!! maybe~ .' :~aY:lj~ saId of~lls~he~ti~s,oftenJollnd; .'

., '., come so gr~at, ,If uncontrolled, that .from. mandpeaF avocB;do or<;~a:rds. Arnongt1:J.e ,> · """, .·~~ocadovarieties.theMeiican ~eedJings, '.

's?ch as.,;N"0rt,hrop· and, Pliebla~ are'espt)" . )clally severely attacked: '. Altl10ughthey , ar.e· ~b( nO.commerCial •. val;Ue;,they .~ay

Fi~~ '. :a.:"Photo'T'icr,ogrophs ' greenhouse

serve as: sourceS of .infestation 'for"com'~' 'mercia! varietie$. Theish,ouid~itherhe .' , removed ort:,reated ·afthefirst. sign, 'o~ thdp!!. ':" ...•.. '"i .

. ' ,.' Among the leastsusceptihle val'iet~~s ,',' are .theAnah~im· andN~al.The FUeTte"

and Wckinson llr~ alsQ relatively resist­,ant when c;:bmpared " with such highly , susc~ptible ,varieties'as Itzamna; Ha~s, Carlsbad, Benik,Queen, Parichoy, Milly­Cand Wu'i:tz~ .' ' .

AppeClrClnc:e~ The. eggs (fig. S,lt)' . art),aho?t ¥75 inch'long whenl~d;and

. arewhit~ and kidney-shaped; They 'axe , ' inserted singly iIlto the l~af tisSueb~­

:. nea~h the epidei:tp.is of'eitherthe~upper .'or lower.leaf surface or ~ntothe £rui~ .(fig~ . 9) . They continue to increase in size and ·.become considerably swollen and di~-toTted near. theend~o£ the. incubation pe~ ,

.. riod. Th,is.gtadual increase in size causes'

. a corresponding swenlngoft~ lealcuti-cle, and the" egg ;blister!!" (fig, 10)' dimot~

thrips. A,eggs in leite .stoges of geveJopment; B;neytlyemerged lst insta~.nymph;C, fl!lIy de-. veloped lstinstor nymph; D, 2nd inster nymph;' E; prepupo;F,pup<;l; G, newly emergedodult; H, ~dult Haul old; Ijodult severol days old. ; ..

:i.ng~ejocations . of the eggs are then. readily seen with the aid of a ha~d leils .... although when the eggs are ;fiistlaidthet~' is no outward evidence <i£theirlocations.

Then,ewlyhatched; nymph . (fig;' 8~B) has Ii small"tapered abdomell.whichdis~' , .... " ," ", -, '. .... ~ '- \"

[ 10.]'

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,J J

~

-,

" ';0

\

~t~ndsa£terJeedirig .a,nd.b!lco~e!!.isH~hdy • · '. yellowish. B~f'Oremolting; t,he .fir~i:. !n~lir ,nymph attaiIi15 !h~ l(:)ngth oLlibgut Yso in6h(fig;,8,' C). It, is"ye1:lmvisltwhite in ' .

-color and has red eyes, as doall,theim· mature, stases •. ' 1'ne·secbbd·iristai1].Yrpph (fig.S, D} yaiiesftoni~ l(:)~gtho£. Ys(f

• iricllllfter th~firs(moltt9about%5 iIlclt '. just beJqre: Pltpiiti(hl~, It> is Yt1IIowish' 'white~ lik¢oldet:lirsHnstaI; nymphs:' , 'A.pecuIiar: ~baracteristi9 'Of t4e nymphs is .. th(:)ir habit ·,of ·carryingaglob~ ule oiliquid {COy,!! on the tip. ot tl,te . last

" 'abd9minalsegment~wheteit is supported" b{si:Xhahs:lslrOwninfig. ,10). This"

,", feca~liq~i~Jsffrst'l:eddish,then bei:omes " bllick: Theglbbule'O£ liqu~d irlCreases in ' ',. "Fig. ..';"Cross sedion of9reenho~se thrips

, l!i~e'Qntil it fallSoff,:then another glop., ) egg, j~serted beneath epidermis of On avocad'o ' ule begins t'O£prin. These arethy "specks" leaf in ,the typical m~nner. (x 109) ,

thlit.dot i J1£estedfruit,and foliag~ "'ag' e throll.,ghout the winter. of 1946-47 pllpaLstage~.Theprepupa(fig. 8, , , '1' ,whereas atthe University, wlieretempera ..

. ~ .. r.i .. s.-a.milim .. e.t.erOfD:lpre'in.Je. rigthand . . 1 h h'Th . hI' turesare somewhat lower, thethfips'sur. yeIo.wi~. ·.w.ite .. epupa,slig.tyla.rger, .' . 'dth' .. ld '. d f'th '. t- . . , 1 . ,. . ,Vlve .. ecoest peno o' e .WIn erm • is a, ~o a~first.yelloWishwhite, Decoming

'. more.'yelloWish with age '(f,ig.~8,.F). . the egg stage.only, and newly hatched Adult~Up. on, emeJ,"ging \ from the. nymphs :~vere not found until the ,niMle

, " , k - of February (fig. H). 'Pllpal,s iu,.the a.dult'is:Whitishth:rpugh~ 'Avocado trees lose much 'Of·their Jo~ , •. ot;tt, • (fig. Q, G); The wing tas.sels are .

":'~£91dedfoiward,hut soonimfold into .. liage during the flowering season, .and th · .. .'. ". . '. . '. some varieties are .nearlyharefor a bn.·e£ . .... eit functional position. Within an: .

,'hpU):thehead and.thoraxbec'Omeihlack·· period;inthe spring. Almost the entire (fig~ 8, H)asdQesthe abdomena. few

· houtslater;Thus the adult female; alew l,loursafter emergence; isblack'Vith whit". '.'

,'ish legs, antennae, and wings (fig •. 8, .'/.)' . The length of the body. is abou~ %0 inch .. · Males ~re practically unknown; and the

. ifernale reproduces withoutfettilization. '. . Development. An il).<1i vidualthrip3

.. may Jay ·asinany as 60 eggs. In the. l~orat?ry, . the _ average.· life -cyCle. from egg ,to the egg laying stage, was found to JJe 46.Idays;I~ 'the'fj.eld,nearlyfive

"generatipns;.·of greenhouse thrips were . . found. in one year iIlobllervati'Ons made, '·on.iJnavocado tree oil the University of' California: campus atLos Angeles. Nearly' Fig .• l0.';"larvae, prepupa,Clnd adults of si?, generations were,found at Carlsbad~ gree.nha'u$~·thrips'6ri carissa. Note eggblis,ters • California. In Carlsbad, all active stages . (arr6Ws),some with exit holeso(eggparasites.

· of the thrips were foundcj)D the IoH: ()(7:5)' . .

[ 11 ]

~ o ... i 300 o o

~ 200 iii: :z:~ .... "-0100 II:

III ~ z

0: (/) ... ... II: co ... 9 ... II: :> ~ II: ... 0-lE ... ....

85

80

75

70

65

60

55

50

45

40

POPULATION

DENSITY

',. ~./ . ~.-----.--

IJ /.

T.E. MPERATURE I\\. . ..

A .,...J' .!\ . .... '. . /-J . \; .~-\.

. A ; A / j\' '-.../ . \/ v\!' .-' -- ~. ".. . \

400

300

200

100

15

70

65 HI. \ . .J}J..... ~., ./\ /-V.-· . \/'-"'\ . \

_IV. ."\ J\' '" ./- " . '~/1\ \ "" . . /'" / ._ . . H 60

M' \ .... /"-./)'./ .. j\J'v"'/"v/ \./V·'v ......... '\ ~55 L" _ /\ /'\, . \ 'M 50 '/\ vv . V . /'-. . "L 45

,:,~:~':K!~4:Ji-:\t~~,~['\b~; R :a;;';;'<.;~;;;1

GENERATION I 1 GEN~ 2 I'~';:"""":' EGG = PUPA ~ NYMPH __ PRE-.OYIPOSITION

.::.~:;~;;I

GEN~ 3 GEN~ 4 GEN.5

(/)

~ 500 :> z i 5! 400

~ 0 ... i 300 0 0 (/)

!!, 200 0: % .... "-~ 100 ... .. lE :> z

85

0: 80 (/) ... 75 ... 0: co 70 ... S ... 65 0: :> 60 ~ 0: ... 55 0-lE

50 ... .... 45

40

/'" \. / .~.----.~./

POPULATION

DENSITY

• TEMPERATURE

~ ~" ."~ . /'\, . .~... . :-.,,-\ /,,"" ~I ;_ . .I ..... \

H'-\ . .. . .•... .' . \ >. " -' .. -.~ . .'.~ .,/,~ .... /fi\/ ... ,. "."j'.\ -'. ,/ /",",./ __ J \.:jV-. \'. . ... \ .. M...... ~~ 'r /'/V .J\F" /\ \,.- '-. <"'\F\ .' V'<.. ". .' /,/.-~,j .. ,~ ..... \ H

L' .' . '''\/ /,,;-.-l" " 'v, \ VV~/\! . . \" . /'L

NOV. 1 OEC. 1 JAN. :::::::" ~~,::;:;. ;:;;;::;:,.;.:.'

GENERATfON.f GEN. 2 GEN~ GEN~ 4 I. GEN. 5 I"""""i\l EGG ~. PUPA ~. NYMPH>II2IIIIII8IIIi·PRE-OYIPOSITION

Fig.l1.-Seasonal·Hfe history and seasonal fluctoationin population density of the greenhouse thrips at U.C.L.A (left) and Carlsbad (right); The population density curvesarebdseq on the num.berof thrips found in 1 o minutes on the trees on which the life history studies were made, on various dates throughtoutthe year. The polygons below show the duration of the life stages at various periods of the year,starting with eggs laid in November, 19.46. .

overwinteringthrip1S population is an­nually destroyed by this severe defolia­tion, and usually tl;1e thrips do not ~ re­appear in numbers sufficient to cause.in­jury until sometime during the fall_

Iniury. Thrips injury on the foliage begins to show usually sometime in June, in the form of small, whitish, silvery, or ashy-gray patches on Iheupper leaf sur­faces where the thrips are follnd in greate1Stnumbers: These discolorations are caused by the puncturing of the epi­dermal cells of the leaf and the extraction of the chlorophyll. The greatest numbers of thrips are found on the inside of the tree, to the north, away from direct sun.

The whitish discoloration. of foliage and fruit (fig. 12, t9P) caused by the earlier infestations changes to a brown­ish discoloration later in the season. The epidermis of both leaves and fruits be­comes thickened, hardened, and cracked (fig. 12, battom) ,and theeharacteristic black specks of thripsexcren1ent become noticeable on the infested parts. It is not likely that much damage is done to the tree by extraction of sap and chlorophyll. The commercial damage consists mainly of the reduced value of the fruit resulting from cullage of the discolored, cracked, and scarred fruit. The loss may amount to 50 to 90 per cent of the value of the crop in some years and with some of the more susceptible varieties.

Control . . The present recommenda­tion for the control of greenhouse thrips is to spray with IV2 to 2 pounds of 50 per cent DDT wettable powder to 100 gallons, plus an effective spreader or wetting agent. Since DDT increases the

. mite infestation, a suitable acaricide should be added to the spray. Wettable sulfur at 2 pounds to 100 gallons has been used in addition to the DDT in past years, but one instance. of severe damage to foliage and fruits was observed when such a spray was applied at Vista while the temperature. was 84° F.One pound of wettable sulfur to 100 gallons has been found to be effective.in controlling avo-

Fig. 12 •. '-Above: left, uninfested Itzamna av()­cado; right, same variety turned white by thrips feeding, but not yet brownish and cracked. Below: Fuerte avocado with brown, leathery, cracked peel causeaby prolonged greenhouse thrips infestation.

cado brown mite, and is recommended for· use with DDT in the inland areas. In coastal areas where the six-spotted mite is present, it is advisable to add an acaricide to the DDT spray.

Avocado trees may grow close to the ground and spread out and .interlace their branches. This 'growth habit pre­vents the Use of motorized equipment within an orchard of mature trees. If power sprayers are to be used, from 200 to as many as 1,500feet of hose must be pulled into the orchard from the road or from such "picking drives" as may.be provided to facilitate the hauling of the fruit from the orchard. Obviously, spray towers are not used, but this does not appear seriously to reduce the effective­ness of the treatment, for thrips avoid the outer foliage at the tops of the trees1

[13 ]

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I": ~,'l:' '", }~( ;~:\,,"';.',

~J~;, se~1dngth~ . cOQie!Joliage;£art~er re; twoio. 4'Qhrtcesof'the32p~rcent enliilsi< '" movedfrorn ihedirectrays' Qft}Ie:'Sml;' ·,.·.'.flahle conceIltl:ate, ~ependiIlg 9nthes~z~ .....• '

i'fb:e BDT"spray is ~ppIi~dat;the pe" . ,of fhetree; have~beeil"fo~ndto result ill a' .' ,riod}vhen the<thripsan~)~g~~ning ,io/comp!etekillo£ activestag~s·aswell as,tb.. .. ,.", · app"earjn'app'r~:ciable numbe~s.This, pe~' . provicie piolpng.~dsrstemieefJ:ect.Systox;:. :, .• (

...... riod will vary£rpmy,earto.Year"depend: " also shQw~promisein t}Ie controlo{th~. . ... ing,;(>nt4e'severit:y"of~<p~eceding six-spotted mite~ Possibletoxk luiia,Us' ··wint~r;8.fId;will·alsovarY II). 'difIer~nto:r" ... o/Jhis' insecticide have .' iiotBeen:}ull-r., cbaras~ .Oenet<ally ,. h()~~vet,tlitsprays; ,. eviiluated:; consequ,enely its use:ld p(esent '. are' appliell'hoill·the:fii-st ' .• o{'August sk1)uZ,j,b'e .confiriedto nonbeiJ/r'ing tree/or,:' thr~ugh OCtober.Bothe,ijleilme'htlil nursery' stock. ; .. ". .' .

: workahdc<?IinIierCiaI expeiience 'ha,(e , : 'FALSE CHINCH .BUG 'sho,,!,nthat thC'!'mostsevere infe!'!tations :. . .. ' may he controlledjqi atleasta year hy , The. fals~ chiophhug, .. NYsius edccte,. ; a,properly appli~dI>:pr spray.,\· (Schilling) I isa.sml)lf,' . light or . dark ' .....

. ' Ej:ght· insecticides:.ha"~:Qe~ti'fo~I1.atQ grayhug l about'% .. iirch long {fig.· 13lt ; . he:rrtore toxic:th~n';Dl;>T:tq thegteen.;i The .. palegray··. nymphs,WithreMish .,; house' thrips, I1.lil~ely,dieldrin; :lindaiie, .' hrown,abdomens, swarm' from dry gr.ass~· .

· loxaphene;c, ci11all, p~rathion,niaiatho:n, lands mto . adjacent-cultivated a;reas,'at. TEPP .. (tetr~ethyl ·PYFOphosPlJ.ate);·.· and: ·.tackirig,.nearlyany'green'plaIit;· There

,SYS!OX, Oft}I~se/d~el~rin sh~ws partie·' 'are from Jour t() seven generations per · ular promise. Al percent di~ldri:ndristat year; On. liluumherof occ~sions ,y()ung: '

. '72 to i pOlmdpertree ghteS'lilhighinitiaL. av()c.ado.treesha:ve heen:attackedand . ',killas well asproloIlged residual effect: ,,' severely:injure~:.The. variety .. minutus

This·efiect is particularlyimportanfintheUhler ,a small fonn, is'also injurious and ,control of greenhouse thrips' because of has killed young:avocado tre~s. For COIl" theldng' period required for the eggs to., 'trol of false -chinch.hug~, DDT or ben •. hatch (seefig~ 11 )'ouring which. they '.zen,e hexachlodde du~tsl,laveheenused

· are protected nom inseCticides in the iwithfairsuccess,but more.recent eJ(peri. , . epiderinaldssue of the leaf. However~: · dieldri~'hlls llotyet heen releasedforu§e · 6:riavocadQ~ pending further . studies ()n

.. ·thepuhlic healthaspecfs of theprohlem: D:i:lanwettahlepc;>wder hasbee.n fqulid<

to have far more prolonged residual ef~ fectiveness than DDT. ' Likewise, mala­tholl 25' per cent wettahle powder at 2 pounds to .l00 gallons shows promise . ?gl;linst greenhpuse' thrips. '.' It 'has th.e~

" aMed< advantage of heing efiective. agairistmites, and is oneohhe' safest of

.. theinsecticides for humans to use. . . Among .the· orgariicphosphates that

have heim mleaexpetimeIltally,para~hion and SystOtc ale very efIectivein:control· ling gieenJiouse, thrips: Tht}'<systemic in~ sectiQide Systm( is~:ffecti~e as a spray,

. hut may also he pailitedonthetillnk.thu~ reaching.the thrips through the sap ';.;fig; 13. Fqlse chihchb~g.Above, nymph; bEllow, stream,'/ls the pests feed onilie toli~ge. adulf.(X 10.5) ..

. [ 14]

dicates that· this material may prove su~ '. perior to other insecticides used to date. Observe precautions in the use of this material as indicated on page 4.

HARLEQUIN BUG The harlequin bug, Murgantia his­

trionica (Hahn), is about % inch long and itS black, with red and white markc ings on its back. Occasionally.it attacks avocado trees, particularly near extensIve areas of mustard or wild radish, which are breeding plants. It can cause serious injury to young trees, a wilting and dis­coloration of the foliage. A thoro~gh ap­plication of 0.75 per cent rotenone dust or 10 per cent sabadilla dust is effective.

GREENHOUSE WHITEFLY The greenhouse whitefly, rrialeurodes

vaporarioru1!£(Westwood) (fig. 14), which is a general feeder, has occasion­ally been found ill appreciable numbers outdoors on avocado, particularly young r,tursery trees which at times may bese­verelyattacked ..

Various formulations of spray oil with nicotine or pyrethrum have been used withsomedegreeof success in the control o£greenhouse whifefly,\Oil plus DDT is

. Fig. 14:~Greenhouse whitefly. The two below are pupae with a portion of the dorsum split and showing where the adults emerged. The

. one above is a nymph. (x 38)

eff~ctive against all stages. Excellent re­sultshave been obtai.ned by spraying with 25 per cent parathion wettable powder at 1 pound to 100 gallons. Parathion is a very toxic material an4. mustbe'handled and applied with proper safeguards. It should be applied bra commercial opera­tor experienced in the use 01 the material.

APHIDS Aphids apparently have become suf­

ficiently abundant to be injurious on avocado trees qnly when the latter are situated close' to heavily infested citrus trees. In such instances, the species on avocado have been the same as those on the citrus trees from which they migrated, principally the· spirea aphid, Aphis spi­raecola Patch, and the melon aphid, A, gossypii Glover. On avocado trees isolated from citrus trees, the onlyspe­cies the writers have found are the dock aphid, A. rumicis Linnaeus(fig. 15), and the cotton o'r melon aphid, A. gossypii Glover. Infestations of these spe­cies have been confined to an occasional succulent twig terminal.

Nico.tine sul£ate,oil-rotenone, orTEPP (tetraethyl pyrophosphate) preparations,. currently being used for. the control of

Fig. 15.-Dockaphidfeeding on midrib of an avocado leaf. Above, wingless form; below, winged form. (x 23)

[ 15]

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',,'_:. __ ' ___ on eittus,shoulddso heusedi:l~ ,,thinly W~~~rr;~6~9~ynetlvor~9f ltvocados. Nicotine sulfate and TEPP are tliread~whichthefeIPal¢:weltveS ,.," vei-y toxic aiul must, be, 'handled with, he;r:hody.: 1h~s,#ford$\ some'prQtection '. proper safeguards. ' ' for the,young for~'a, while before they

'L"O' , NG' ,-T' A' 'IL'ED',MEA" L,Y, BU,' G start; feeai~g, ,Th~<productfonof young' 'takes pllt~:foraperiQdofftom 10 to 20",

,The long-tailed ~ealybug., l'sep4ococ~ '. dllys~,w,iM~p:average of about 200 YOUIJ.g , ado'nidum {Li~naeus ),{is.tJie 'roost produced. An averilge of ,ab~ut6 weeks is,

'" ofnve spe~ies;ofmealybugs 'requ;ired,fortJifrmealyhugst<t reaQhma- : " " >may'be:f<;lund .onav'6cl:I,do trees~ In- tq,rity.- " ", _', ",."",:, ),~ry from th,is,' specie\!, is practicall,y eon-lniurY~ InrecentyearslIlul;:h gra,(ting ,fined to the scions of newly grafted trees has been~done,inthe coastaL areas, on

, " hi coastal 'areas. , , avocadoVllrieti~sfotiridto he ,'c6mmet.,,:' Appearance. The mealybugs, havecially ,unsuitable, in the,localities W!her~

',soft,oval, flattened bodies in which thetliey we:r'e plailted:, Thescionsare.cor" divisions ,betweenhead,iborax,a:I}d, abo, 'ered with, pa:peibags,~' keepthe,qirect domen arenotdistinct.'r4ey are covered , sunlight oil the newJoliage. Theshl'lde'af­w:ith white, mealy wllJ(, 'a:n<I usually haV'e fOJ;dedhi,.th~~e bi:tgs , mllkes,:it ppssihle', :' marginal' w~xy· ·filame:n,ts .• , of.· variable for the me81ybj,J,gs t9all;ack tb:e.new £0- ~

"thicl$:ness. and .length;' and two long "tail"· " lillge.:Pfedatorsah~ parasites are p.otable ,,'." filaments (fig. 16): The body (withopl tocontrolt4e'mealybugsintimetqJ,ave ',

:tail) is about ~'inchlong. ,the scion,.whic;h'is usu~lly ~il1edli:r)less ' " ,:Deveiol;lmeni. Unlike other inealy- other cont~olsare employed. :. " ".

bllgs, the long-tailed mealybughellrs its Control. In grafti}ig,the trunkot. , ,young alive. TJ;iey are, bQrn" under a" s,everal'larger limbs, of ihc ,tte~s are .,cq~' " '" ',',',,' off and usually twoscio:ns arep~acedin

clefts at. either ~ide of the sawed-off< area. Mtergrafting is done,thetop of the: trunk orlimb"aIid the sides. for ahou~ 6 inches from the. top,<sholild be treated with chlordane., The following materials '

, 'ha~e'been~sed ~ith·'succei\s: 5 percent" , chlorda}iedust; a spray .of50per cfmt

chlordl'lllewettable ,pow-d"l): at' about % ounce tOil gallon QfWltt~r;~Illi

, a.' slurry con~istingot2 pounds ()£50per ' cep,t' chlordarie,wettabl~pow.der fol,~al~ ," . IOnofwater .. TJ;ie Jatfercal)., be paint~d' ' onto the area,to be protected, ~n(:l sInce". it leaves agrdfiter ampunt"of chlor~a,ne on the tree, it Should , be the most eilec: " tive method of ~pplication. Itm~y:a!so prove. to he:themost.qon:veni~t.,H~w~; , ever, all .thi~l1.nieth04~4ayeresulte~ iri good protection of the scions untiltlle:' . new groWth .lsabo.uta foot long;aftel"" '

. whi~h it :noloilgerr~qllit~spr9tecti6n .. lt,-: appears thatJ:4e effeefivenessofthe chlor~ ,., dane depends primarily on its ability to . , control ants. "

\

~hellthe' gril~t<ileft;is;q{t~¥~d,'i~:cis ...•. '. thepr.l\~tice to re~eal it,' an9.a~yih~cti' ;, cide ~p}llied' be:for~tl.te. sec<md ~p:pliCa. ti~ll. of.seafiIlgsu'bsfance is'ther~bycov· .ered 6ve~.InaIluIhber of experi,ment!!,it w~s only'. on trees on. whicl).!tJje. gr~ft defts wereresellied 'after. theapplicatit)D 1>f .the insectiCide that mote> thl;i:n . ~ .... occasio.nal· mealybug was :round •. 'The ' g*~er sh6uid be notifi~d; # ,and when '

: the graft clefts arc to be resealed;.· and tl;i.einsecticiilc!!houldbe reappliedtothe····

'aflected tree~.. . '. . . . .•.. '. '. ..' . . '])l)'F;~pr!iy,as ufjedJor greenhouse, thrips:t;esultsill aredu,ctiopof the mealY" ' bug popqllltion'forat lea$t ,·.a halfyeB:r" f\ftertrelttmellt. It may also .. be used as recomniended above. Jot chlordane:

UNARMoRED SCALI!! '. . .AItt<>llg <the unatoo<>ted sCales- attack~' ingtheavocad() are the softsc;ile,C~cc,u~'

· hesperidumLinnaeus. {fig. 17),henH~ .' (!ipatscalepest ~f the avocado. Orchllrp$ . ·spher~al.scale, Sai~setia. hemisph!tertca '. were' sprayed or fumigated forthis,pest.· · T~rgi6hi, blackscale, S.oleae (Bernatd), . Gradually· the latania scale became. les!!. an.<lthe European fruit lecaniuin, Lica· serioll!! as a pest, apPlJ,rentIy be.cllp.s~ of riiuTri:corni Bou'cM: These are allqU,ite' . the . increasingJIJlPortance. of natu,ral

; efEectivelycontrolledbyparasites, alld enemies, some' of them introducedi;n rllr~lyim::teaseto morethau. .~'. local" 'recentyeius~ Today, growers.seldom ized infestation on a'n oC9asionat tr.ee '. treatfoT latania scale, although .some- . ~n ·the. ·orchard. H. treatIn~nt appears to times it .becomes ratherabundant"on"/I'

,be::nec}esslIry, these. insects can .be con" few· scattered trees andcauses some.de· troIlec:l by means of· oil spr.ay, '. provided . grading. of fruit. It is generally believed," < .. '

· .th~,freatmentis tim~d to coincide with ' however; tIlat the bene:6.ts of treatment the o(:currence Of .. the young,. vulnerable.. would ordinarily .. ·· be mote ·thanofIset

. instate, oipi'ovidedrepea~edapplications'hy 'the upsetting of the natural balan6~ . . .. ' of spray are made to irisure the control of between the pe!!t· and its natural en¢mies:

theprogenYQf those insects wh,ich may I;\ppeClrClnc:e. The, lataniascale {fig. have been..resistarit at the time.of treat':' 18) jshY far, the most common ofthree

'm~nt:Mal/Ithon is very effective against .. ' species of grayish, . circ~lar, J~attened, . the sor(scahf;Control of ant!! wiilaid. in . armored scale!! ,thafmay be {ollild ' on.,' .combatingu:tiarmored .scales. . avocl:\dQ,trees;The latania scale is cir·

c1,llar,<7i6 to %2 inch in diameter, and, rather.' strongly convex; If the hardenea;

. ,_ lat!1Aias~ieinhabit!!, many. re- grayish armor,ofthe insect is lifted.ofE, gions iif the wor~don~,wide variety of. .the "Soft yellowish body may bese~n: .. ' hosts. In California,however,itwas prac~; De"el~pment •. Up0.n turningove.r:.>

. tic~llyu,nknown u:nti1a,survey rnadeby; the!!cales, o~e mllY oftehfinq the yellow-':' state.amlcolJnty oijicials in ·1928.re- eggs, or: the sulfur'~yellow; <ictiyeyoung

.veaJed . that it was at. that time the prin. "crawlers" that hatch within.a few hours:

\

ih,ed;~eI1~a1),dpossibly.. onofu~r thin"' skinnedvar~ti~s,. the be:ak·ofthe scale

. appears to 'cause ,an . irHt~ti~n:inthe fIesh,asindi~ated hyi nodules·a.dhedng .

. tothe'lnside oJ.~hepeel·when it is . reIP?v¢;,.GOJ:respondi?gaep~~sio~15 oC~'., ' , cur III thei:flesh ohheppeJl"lllt. The Ana", .'

.. hehn appears to be, the lnostsevereIyat . . , ta.cked. of . all varieties.

C~ntrol~ Malathon 2& percentwek table powder at 3pmllids, or the 50 p~r

, cent em~lsifiable solutionatl% pints :tOr 'lQO gaUons;is effective against the lataniascale .a$ weIi. as ~egreeIihouse thrips, omniv()fo1l8 ·looper,ora~geior.· trlx, and soft 8cal.e,J}nd it does not ago gravatethemiteprobletil.Nd "'off:flavot" .' was".detected .. ~ll" fuerteavocados .atter., . treatIllent~ithmahlthonat • the 'above: . con~ep.trati~n; Light'p1ediumspray.()il,., .. ellluisivesat 1 ~{ per cent, arid· emulsions • ' . "

. . . ·at2percelltJ::all'also he u. sed ipthe cem: Fig. lS:.,..Smalli see-dlessavocado(lIcuke~/) , .

,with lata~ia scale. Note ,pits~aused by the . troCo£ l:he1atania' sc~le. HoW'ever, .an oil scalesAX2.6) spraymllY not suffice toco:l1trol asevere:

" infestation. of 'latania scale;particuhuly "Thes~ usually settle . nel!.r the parent when ~e scales are soabi:m~ant that their

within a·haIfa dayafterhatchillg and, bodiesoverll!.p. Inadditi<in, oilspl'<lY'is like other armored scales, beg~n se· sometimes ~n~uriousto th.e ttees~dlI!ay creting the wax that forms the scale' reduce the crop for the Jollowi:ngyear. coyering.lnabOllt2 weeks the i~sect A spray of 25 percent Pflrathioll wet· undergoeS its first -molt, the Illolting pr(Jcc table powder at2 poundS- to 100 gallons, ess requiring 2 or 3 days. In 16 to 19 as it has been',widely used in the control days after ,the first molt, the secolldmolt of the> red scale in; citrus, ltassltoWn occurs, .' and • the insect enters the' adult promise. in 'experimentsi,n which.· it .has stage. Males. have been recorded by ,sev_been.used for the control of latallia scale

',eral, authors; Qut have Dot been found in Ollr' avocados. ,In, addition, it " is 'highly. ·C~iif?rnia. Isolated females' lay eggs, .' effectiveagainsLgreenhouse thrips/:lP-q. ,proving tltat they can reproduc~ wifhoutapparently all, other ipsects, exceptfol. " fertilization. In about.· a month • after the .'. the soft brown scal~, and has' some value '.'

. second molt, crawlersliPpear. Ithasheen against mites.. Parathion is a· vetyto:xic found tha~jn suminertheJifeeycl!~ of the material. and . must be handled and·iJp· latania scale'is about· two months. . plied.uJith·proper safeguards .. It 'should

1riiury:. Tlttl'latanill scale is u8na,lly 'be ,ap'plied by a c.ommerCial operator ex­IDost abundant on theb'ran¢hes or twigs,perienced in ,the useoftherluiterial: '. but may appear on the leaves and.fruit ..... .' ., . iisthe. infestation increases. TJiesmalle,r: . OrHEJt ARN(ORED SCAlEs' twig!!. may .be. kille,d.lhe fruit is . de-.fh~ greedy~cale; if-erniberl~siar(J,pax,

,....graded or cull~dbecl!.use ot~ep~esence\ ' (Comstock),.;i!!;sixni1ar tothl'; 1I!.t~lIiia' r.' of the ,scale!! on the. peel,although. the .s~al~ in.out,",ard. ~ppeara~ceand carb~ j

·,.~u,aFtyo£the ,fruit is not affected. OndlstInglwshed ,WIth . certaInty only.by.

-tun

microscopic· examination of properly mounted specimens. In California' this species is less abundant than the latania scale on avocado trees. However, an in­stance of injury to young avocado trees has been called to the writers' attention. In a three-year·old orchard it wasfou,:nd that greedy scale had become abundant under newspapers that had beenwrapped around the trunkso£the trees to protect the:rn from the sun. The trunks in some instances, were .somewhat distorted by the scale infestation and it was believed that the resulting weakness caused them to break more readily' in strong winds. The control of th~se scales, if necessary, would be the same as for latania scale.

The oleander scale, Aspidiotushederae (Vallot), like the greedy ,scale, is not readily dist'inguishedfrom·. the latania scale, but maybe identified. with prop­erly prepared specimens. In a survey made by the State Bureav.of Entomology a,nd Plant Quarantine in 1930, 17.6 per cent of the scale-infested avocado trees in California had oleander scale. This insect, however, has never been of ap­preciablecommercial importance. The control, if necessary, would be the same as for the latania scale.

The dictyospermum scale, Chrysom­phalus dictyospermi Morgan, is. a circu­lar,armored .scale, :;;16 to :;;12 inch in di-

ameter, with armor yellowish brown to brown in color. A survey in 1930 showed the dictyospermum sc.ale t~be quite abundant· on av()cado trees in residential properties in Whittier, Gali­fornia, a} that time, but very scarc~ in commercial orchards. After the known infestations of some importance were controlled,this insect :qeveragain in- , creased to noticeable infestations on the avocado in the Whittier area, but has oc­casionally beenfound and eradicated on dooryard avocado trees ·in Santa Paula and near-by.districts in Ventura County.

The. California red scale, Aonidiella aurantii (Maskell) is. circular, reddish in color,imd averages in. size about the same as the previous species. This scale insect" if it is present at all, will usually be found only on occasional trees in the orchard, generally in proximity to some more favored host, such as citrus. Some­times a tree may be severely attacked (fig. 19) while neighboring trees are en~' tirely free of the insects. An exception to the generally spotty distribution of the red scale in an avocado orchard was a. rather heavy infestation in a 15-acre or­chard of the Fuerte and Ryan varieties atMonrovia, California. Theorchard was sprayed with 1% per cent light medium oil,with good results, on January 25-26, 1946. .

Fig. 19.-CaIHornia red scale on an avocado leaf. (x 0.66)

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. OMNIVOROUS' L60PER.· ." ','"nea'tlY. white )be~eath:'$wu 'irteg1)1ar, .' '. As ..the cOmmo~ ··nll.me . implie~, the·'·' dark~r; iraIll;1verse mtldian baNd~ ~r(ni$ilitl:, .

omlliv(jtous looper, Sabulod.es caberaia uJ)pefsutface.lt D3:S a wing e:x;paIlse Qf . Guenee, feeds on a large'nllmbet o(about. 2 inches; These attractive moths plants. The term "looper"derivesrr()m ilI'e~eldom see~during thedayh~cau~tl the crawling habits·thanne insect shares they cli~ wthe undersiqes'9£ the leav.es

'with other species of . the fll.Ill:ily. "Legs" jwiththeii(wiIlgsspreauassh0'Wl! jh fi'gu!e .a~eabsen! #OIn the :middle of the body,' 20, and fly about. only at 1Iight. . " .' 'andth¢reareonly t\v'o Qr three pairs at . ·.D,e¥:elop~ent~Thefeinalelaysfronr " :the hind end. The. larvae must pull these; ~OO to 300' ~ggs; These.lI.rc,de.posited. in

.'. up dose to the true legs,' located ~t the. dusters on. the, ullde.rsidesofthe leaves, / , ftont end,thus loopingthliirbodies (see' eachchisterconsjsting offrom 3'>to 80

. picture, inside: frontcoyet) "Then the. :eggstest~llg horizontally on tl,ie leal SUI"" , "legs" arefirmlyattachedlQ the leaf ~nd.face(lig~21.J.They~eat first metallic

, thefoteendo£thebody isthIiJ.stfqrward;.green, hulin ~.daysturN tOll. chocolate:. . Leaves that.haveheen partly devo.ured brown.:They hll.tCih in 8 or 9 days: ..... '

by. the omiiivororr$loope:t:Jn.~y he£ound',. . !hemst-instar larva isatmst p~le on' al:ino.stany.avocado tree, and oc- yellow and isthe sameJength as the-egg;

'. casio.nallyseveredefqliationmayocclIl:; .' It eats only the eptd((nnisofthe upper, . . The. insect s'ometimes feeds on the fruit . surface of the leaves, .leavingacha:t~cter.' as weIr ,as.thefolill.ge;howe~er, .~nditis istic brownish mdnbrane: All theotber

'. undertheseconditio.IiS iliat it becomes a,' IarvaUnstars·e~tallthewlI.ythl"ough th~ -- >ser.io.us pest. Fruit damageseeIDs to hare lea£. LoopetlatvlI.emay eat holes in~o. the

become serio.us·· o.nly in recent years. It . "leaf awayuom the margjn, ,but are more. ,is graduallY'increasing in. impp'rtance. likely-to.. eat the,ir, wayinfromthemargin' .. 'Appearanc;e~ The adult :ttI.oth (fig.. o£tbe leaf. . . c c • c'

. fO) is 'dull brown o.r.' yellow above 'and The repl:ainirlg • inst'ar$ area ytlllpw to., ,"

\ b

,Fig. . '. ... . ..... < .. ; .. ' . eggs of the ... ..... ' looper,gre~fly ri1agnifl~d.Fig; 22~ ....... pro-.. fecijy~ .co~erin~$forpUPRoftheom~i"ordus loqper. Cenh;~: tylo I~aves ""ebbed togetheri right!

.' ,edge of a leilf folded back and webbedh,to pdsition. Note feeding injllry. ..

pale greeI\or pink; withyeI\ow,brown,!3:iv{)darp.ageto. ftuitwas seen inah {lr: or green stripes on the sides and back, chardnearVista,California.Young beside~a number ofblackntark:ings. The fruits of th.e F1,lerte yariety,abOiIl: Ito:

,·fifth and last. instar of the: larval stage- 1% ,ncbes long; were being attack:ed J:)y . (seepict~re, inside fronlcover) is 13h . omnivorous looper larvae {If,the iSeconq

'to2incheslong.TliegreateiSt.damage is, and third instars.Thesecausedshallow ;, doneby:thiiS iri~tar.Dhe individ1,l~ may Ieeding scars ontlie ri~d (fig.- 23, top)

. eat. an avocado leaf ina.single qay. ' . and aifec,ted a:b01,lt , half the crop in the . " Th.e pupa may ,be found webJjed be-' infested" orchard: Although: the. larvae"

tweeri2 leaves or inside-a leaf that has were kilIedhyaDDT spray; and f~rther beenfo14ed and·webbed'togethe:.;:bythe infestation :inthe 'aifected"'orchard was full-grown Iarvaf~r thepu~pose6f pupa- prevente,d, it was, n~ted that subsequent tion (fig. 22) .It is at fir~t,a pearly white,iIlstarsate(1).t h()~{)s as, much as ~ inch blltbeco;mes:dark hrown as the time for in depth ill the fruit i~ the iaboratory, : the ,emergence'. of,the adult' approaqhes: (fig. 23, bot:tom), the resulting ,inj ury. '.' /Th,epup~ isabo1,l.tl14incheiSin}e:n;grh.appearing ~much.like ,that .causl<d by .'. "'ThelifecycI<1' of th¢' omriiv();rousloope;r , snails. These larvae' were' reared to mao. ~. r~qUires ahout l%monthsin. iSuIJlIlieiin turity on a'diet of huit;alon~, " . . • .. '¢oa~talSan Diegol:ounty~ .an.d appi!rently.' 'Q~niv()rouslooperiSwill attack the ,thet~~ayhe 5, or 6generationiS'per yeai-~ fruit even when it'is not adjbining an-. '

l~iury.The. omnivorou8 ... 1qoper 1,l8U,-' otherf;ruitcorlJ,leaL In this respect tlley ally Jeeds only on the foliage,{fig.·22). diifel'.from other. moth larvae to be also'

, If· a $uffi.cierit. percentage oftl).efoliage crlssed later. , is.r<1moved,thet;reei!\:of CQurseweak- C1)ntrol~Before DDT, lead 8;rsenate eiled arid the follc~~ing year's',oIdp is, spniy: was 'recommended as acolltrol : reduced. measure; The fOrIp.ulawaiS 4 pounds of "

In luly,l949,the first case of exten, acid lead arSenate an.d 6 ounces ()f blooa<,

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il~~.t~~915P~:\~! t~;';;c, '!i:yX\\f ;11"!'i~;\~'¥' ,. ',;, ' - "\'~;

""",11>1+''''''" ';i~ ~orit~~rtt' ,C;alit()rnia;,ftl~

i i'

. pr~ferthe .~yogado as' a h{j~(,·, . '. .,.. . .' ... i~generall)'notso aJ>up:dant .. ' '. the 9mniyol"9rie,'~ooper, : and; thefac!

, ,thatitcan. feedpp: ,fi,uibi o111y~herethey ..• ,may'b~-W'contf1.ctwlthone an9tb.er,or

. ,~j~aj~al'f9ttherred~c~. itsimp~rtaru:e"

'· •• ~·.,.t:'~~~!~r~~~~.'The,··~dult,~etlr,;(~g .. ,;'2~Yha!la,wlIig.e,xpanse<lfl:iiicb.,:being "

only~,little over,halVthesl~e6t We o!llll,iv()~?~,s,l<l<Wl'lr;~~d/the ." fOl'~'ViIigS'

,:arereddishhrown,Themotnswhenat . ": resyhavetnebeU~shaped'o~tli~thAt.SO ...•.•.. fiequeil:tly·. chr4c(e~i~es:tbe'leaf.,.roUers.,

.' •• '., The ~uter:cPr1ie!: of '. the£orewiIl,g~, is usually.· somewl,tat,nQtche(LThe ·.·itdults

" .arenocturnal,~n&r(lst;6nthe ulldetsid~s" oftheJeav~~duringtheqaY·'>' ' •... ,'

D,ev~l~plt1ent. Th~alnorbia lay~its,. ,egg~ OIl, the upper surface of tneavocado '

,leaf,a,long the midrib. The greenisneggs .' .' .... . iarelaidin fiatma.ssesof from,5to 100; ~lbti~ih. spjead~:r" to 106" ,gallons of . and flwn 400toSOO~ggs llla:y.beJaidDy

,"wate( This spray'waS'riot founoto be ···a single II,loth .. Th~se· hatch .in···fr6m~J3 eptirely 'satisfactory ~sa'coJitroL' . toIS.days. . \ .. .. " Ithas been notedth~tin1;hecollsider-- Althoughthere may: ~easllla.nyas ./

,@le acreage· that has beell' sprayed with .• seven laJval instars,pu pation roay .' take" D9T fer greenhouse thrips the omnivo" place after the fifth,QrsixJh in~tar:The 'rous looper has not become a p~st.About ,first-iI?-star larva is /lmaU:a;r;'dyello\\,ish an hour after the spray ilS aPI!lied,the, green. 'l'helarvaeoLthe remainipg in- . larvae begin 'tofa:lhothe grourid:ina stars 3Fe.similar in appearallce, except 'paralyzed c;ondition. Whencollected~and Jor siz~, the.seventh-instadatVabeing% ~broughtto 1;hehlboratory,theydie""ithin jnch to, I1js,inchesJong(fig.25, top}. 10~or 12' houri!!. E:Ven though.thelarvae' Larvae of all'instars ~us.1;1allyspendthe may pe prQteeted from, th~'spiay hy .. · a day hiddenbet'Yeen two leaves that· l,tave

. _cover of leaves d9-ringthe,day;theY will been webbed together, or between a leaf s~ccumbtothespray . residues when '~aIld a. fruii (fi~ .. 26), in thish~bit.re~ crawling ahQutandfeedirigalnlght. One. '.

"JlouIl,d Qf50 pet cent DDT wettable pow­derto 100 .gall()ll[;;;ls effective.lf.control

,.<?£ .. , greenhouse. thrips is desired; the .aIllountofDDT used in the.spraysh<:>uld be d,oullled: .' .

. .

AMORBIA This. moth; kriow~a~ AmoTbiaes~ig(J,na

'Busck~ isa tortrieid{leafr§ller)motn thatwas first recorded in California in'Fig"24,";'ATl1orbicj~ittiwiiig$ 1922:. It has Men found i~an eoastalticin. (x.3.4), .

[22 ]

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-'- ;:,,\~<~'::;:f;~~~;;f?(.'-·: :"'~';::- ~,,/;~

': '\.':~':-<~<~/:: ",:~

.lnAugust,l949,. am~rhialani'~~,to~;' ~/' i~ . ·witlJ.laryae qfthe . orange tOrtiiX:,'; .' {iVf:

IJ.n~'Yrota:enz:a citrano;' (f ernald), were:;'; .' tobe ~esti-oying theliud~ ofnewly:.i';

; budded aV()cadotrees.The Jarya~ fed on.. ....... '. thehar~ «~lj~l~ing'the in~ert~dhuds,qn " .. ' . '.

':)hebudi;, theriiselves, . and. o.n any. g:ro:wili ' . ; ;:that fully hAve. deve'toPedftoni the. buds ...

.' SeIIlblhigth~laivae~Eth~ "uini',rnr''''''':<' )Qq~er~.The larVae .... .1.0:;''''''''' VT''lIp.nfl.V

/~alltothe. ground If .. ' '.' . . istnQlestecl. The .duJ:"atiori.·· of the • larval .

They w~re fou~d only ~under the-tape that:. 'iSl.l$edto: keep the buds in place; . '. '. . Control •. As .lor omnivorQus looper, p.2L .'

.. stage;iricludingseveninstar,~,wasfound. . Fig. 26.-Above: .. Ieft, leaf webbed to, an t()J)e~boJit two monthsUndetout~()or. a"O'cado, under which an.amorbia is. feeding on

.... conditions.in late summer. . '. , . the fruit· peel; right, leaf tu~nedo"er to .reveal" . The<PllP.a(6g. 25,hottomjisfrom %~ebbingth9t conceals larva during the day; to ~%,iJlchlong. At}i:rst it i~ pale gr~en~. arid the scar on fruit, indicating area. oyer which. lat~r cliangingtochoc9Iate brown. As.:. . larva ha.s fed. Fig.27.--':B~low: ini~rycaused.· in the.Case of. the onl,nivorQus looperltlle .by amorbia, as ~t appears on mature fruit .

. , larvae weh .two leaves t()gether~'to' cc;m. ce,al .• tlremselves du:ring .. pupation ... The pllP/il. st~~e . requ'ires . an .. average of 17 day:si.nsuriuner~ ..' ! .... .

. Iniury.On.the leaves, the amorhia . ~ails~ a~keletollizing~iinilar to !:hat . callsed~y:tneolllnivQr.~us ;looper .. Some~ i

; 'tiInes the.tertninalleaves Qf a twig are tied' . t()gelherhy: qleaqs of silken threAds,and thelatva will feed on the t¢rniinal bud. TheiaIi'a wi1lalso I feed: on fruit if ~,

. ·.hiding placeispmvided, sUch as an ad· ···jom,ijig;leaf,. The young fr~its. are the

ones>Jilost likely to lie att1lcked,aIld the . scars catlsed.. by' the, feectmg .1!ecoIrie. en· . ,larged·and.mdreconspicuous astlie fmit mi;lture$(fig. 27)., • -.' ~..

,~

~

~

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IY~1:~~~;~~~~:~~~,?~/' : '~" :f~,.~ ;:~ '/1:--;,i,., ~ ~<\' ~ ~-'; .'_,~~ \,~<t~~l ?f~~~;;r~~JI?}~~;~~c:~r~~~~;~~dj,:~;,,::; :~:~0~1;:.~~::3(';·;/; -"f?f':"/'~~'\ ',';~:..,;:::/ ">\;"/' '~,.(;".,~,,_ .. ,~ ,~,,:,;. "\_'(;~,'< ,.. '",' '-;-'.;'~.,;-;,': ::~"{I:~,> :,,~'-<.> '-:·'<·-~·"f.:~~-·-' <,".!.'""; ~~;'_', '< _ . ,;.~<. >" )'- • . .\~-/'; i.:):»:;~." ."'i",, ;"'i, ',c./ ::._ .••. , ..... '/) .•. ' .•• : .•

-e '·'r .. :;'" ,.j''; -', ""01,1' .' ' , ',,'.'

':<,;.·'t : ::~ Q~~ •• ,;,o~t~IX':' ~>, ',: we~ the te~i~ leayes of twig! together >,' The orange',t9rtiif(; .4T~yrotOiCnia cit"', ~d f~ed InSIde on the terminal buds.

" ,q~:tF€l:ruala}js,~stnalneaf~:r(5U~r:inoth .·:LIke)VIse: the bases of larger twig13 may •. ' ,'.ih~·lias¥ee~:k~()~.~K:an,··ol:ang~;p~~t ·.·:b~gi:rdled ,at.'.ihe.pointottheil'~ttaqh:. i'n'C:.ji:1H()!~iaJQt'fuiinyyears., Iti.)tJ49' .. ment with laJ:'ger:hranche~ (fig.~8;C);

... , ·.'this.,ipse~t;:w~s/fml11(t to;pe ; daj;ng:'II.:: Th¢ in J?~e,d.'ar~ain ,suchcases)s.u$uaIly' .. '. i .. )i~i~danW:l111t?ta~~g¢tQ ,aV'~~aaos::cbvered ,",fth a white sug~,called "dulci.; ..

. ..,:':'~~~~~~i~(s:~ 1;%:~~~:fi~tr:~;~· ... ·,~i;'Pfat .. e~ud~s, froin".ih~:~ou~~ •.• '(fig:.

\on:t~~;llyJlC4qo,. .'';;''';'(: ....... > DUI;ing the hloomingperiodthetiny '.' . '. '·'Appe,C;trPi1lc.;,The.·adultfe~a:lesh1fteJal'Vae are s?~etimes fouila inside the/ . . ' 'iii w'irtgspreiid " of.aV9tlt"%'··.iricIl,:arid· the. .flo~ers, .. where . they . D;layfeeclon .. the.de~· '·l¥~le~(.Il~·soine,",hd1;~irl~ller;1'he .. mothsve1oping elllbryo or the.calyx. The same , '. a~~".~ufJ~colpr~~~·; 'l!iid,tJ1e~r,''l)el1-shal'ed .. ·liirvii~.1I1~ylater fonn a, nest . of~everal ;w,-ing,s)ie- a:l~ost:fll}t:o'Ver'the.ho4y'(6g:" .flQ)ver '. heads and feed ·ont!le. 'baseso£ '28, .Qr~lJsuallyea.cJ!:winghasaaark,ai" >,~eflowers or Jartlle,r.doWn .inthe long agona!.Wlld.' ....'.h. . ...... . ••. . .... J.·st~ml!of theflower~Illsters.,"Nests"of ..

l)evel.opnj,nf.Ma:sse~ .. of pa1e,green ' .. flower parts D;lay so,metim~sbe£ound. at ... ' .. . orctean1;.folor~d.e~gs;' overlapping '.like .. the . point where se~eral.··. etems. of the ~h,i~gles, ~ay,pei'found6n leaveeor;flower cluste,rs.are i oined, and ilie larvae S'~oo:thgreel).Jjark,'rh~i:emaybi/5i07 may be found feeding und~r,thenests;

·.la~aUnsta:rs;Thef~lhgro'Wl). larvae' are '. Like theamorbia~the.orange tortrix' '. abo.ut·*hwlil()ng; and may .. he straw- Cmayattackthe.terminal ~l1:d . after ,tying . ~I<?J;'~~,.ligh,~ > tan'. greenish, 'OX; .' .. rather .. ': . together the . tendeJ; termInal'leaflets.for. snio~Y;Qolored (fig;~).tikethe larvae,a • .hidingplace; It may aleo deshoythe

'.' of theamor;bia,; they .atev~ryac~ive1Jlld·· ..• b&ds of newly budde,d; trees. The tape ;. will :wdggleaw~y~nddropfo:the gtoundhol4ing the bud in place, . gi~es ~., same whend:iSturb~d,.oi:iema1nsU:speIided on type ofprotectio~Qrdinaiily 'afforded'

.' ,./), silkc;mthre~d on which they can cli~b by the nests of debris. .'. .. '. . . , . ·again.;Thepupaeare about % inchlong, . ,andllI"ebrown inc.olor.They suspend. ,th~:r:qsel:v:es by means of small' hooklets at thilnarrowhindend' of :the body. .

In the. laboratory, about twonlOriths .at .. T?Om temperature are t~quiiedfor the,

,development ofonegeneration~ OUt. of ' doors,.,jn .. the coasta~ regions, ,vari()us . $tage!301 development niay be observed at anytinie of the year , but there,arepr()b~ ably .aJjoutthteegeneI;ationspe~ year; ·hliurj.On aV9cadosthe mO,st frequent ..

injury O'ccm:li near the periphery_ of thi' i;reeon terminal twiglets. The larvae' feed' Qn th.egreeri bark and: 'often girdle the twigs (fig; 28, .Aloe' sOD;lethnes eating"

>h6Iesin.them. While, feeding, the ,;larvaeare covered by crude "nests" of , pla:qt d¢Qris,;andit is these nests that at­

tractattentiontot}te feeding. Like 'the ..... amorbia, the orange toitrix . may also

Fig . . 2?":-.OrQng$ .·'.tQrtri~: 'Iarv~ and iniury cause9to avocado twig;The"nest'~ of.d$hris; and the dulcitol .have bee~ removed to expo~e' Jarva. (x 2) .

[25 ]

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, '.',~ : .. : :. \'

<'~1'lie<in;;'st ;:serious injury been ihe~carr.ingoUrui~ ,,' h,,,, .. ,,I·'h,,'·f' ......

.. Jeeding'of the l~rvaerThei,nj InQchlike that causeghythe d·tnriiv(1r6.us~ .l{)ope,:. AsW'iih\theamorbia,th~ex'Lt:uL'.U"J : dllInagein, ali orchard islitn~J:e(;I. .. . .... ' ··fact . that fh~ illrvae. will feedo~ly •.. ' ..... ' .•.. ... pointo~ contapt;of tw:o fruit~ orwh~i:etb.lt· .••.

truitmay be in contact with a iI(laf., : " " ' C9ntrol~,Spraying with· 2 pouIl<Is ' SOper 6eI}t DDD wettaJ>le' powder to ' gallons, is effective in, " " , .

, :or;inge tortrix, and thesmb,e trealrneiltl,S:", 'also, highly effective against thf~ 'o'mIllIV(h rQus loopet:and the, amorpia;

HOLCOtERA ".,' A small,slender;grayish'niot{i,abQut.' '",' ". ',. .' .' "'. .'" .;'

Ys inch·.in length~ !&own, asllalcocena) shalloW .. }!Ii~nrieli~:iheireeh.'h~*;ofthe'·' '. ,iceryadw: (Riley)'" '(~g., 30,.,1e£t;), 'll?d, .'tlV~g:bt)IleaW~~~r,nes~i Onlrra:r~lydo

at least one other closely related spe(}les " ' th~y:i feed ~eply, 1n,tothe' twig.> To qi'tte .. (fig. c 30, right ) , .• a:epr;iniarily scaV:- ." "thei hav~pr9yedJdhe, of,practicallyno enge:s, hut Qccasionally fecdOI) live .'econ,oI11ic,i1npO:i1:~npe"oIlavopados;. ' plantoran:imalmate!ial.Their n~sts" . '.~ ,. ,

,(fig~ 3l;) . are much larger)mdmore c~re",VARI.GA"'E'D~UT:WQRfVl'" .• fullyf()rm~d than, those of the" ()range.. Am~ni t4~;,sPQ;adi~." pest~that.oGe~~ tortri;:x" but are not so I1umer,ous.OG~sionally,attaCk yoting~vocad9t:re~s,par~ .. cas~~nallytheyare. attached to a le#. The ' tip~lar1y, near..l~rge;linculti\i~ted,atealj, '.' larvae when full-grown are o'nthe' aver- . is the: variegatedcutw()rll).,PeridrO",,4~: ,age slightly longer thanthellloth~.TIJeY ,margaritosa (Haworth). The ailults are 'are bro~ni~h, with;broken"."longit;lld~nal. grayish brown moths with dark moltled stripes. TheyusllalIy'feedonly onth~ £ore~ings and a wing expanee of Ph to deb:risof whichthe~r:iiests are cori-"iinches.Thi,Sisone ,ofthtJ nigbt>,Rying st:ttlcted, .but somethnes '",ill' ma.k;e ",Ii moths or ,"millers" cpmm~mlyatttacted

tolights;. , '.. ' , " The futi-grown 'larvae ar~ ,ali6utl%'

incbeslong,yariahle in col6r;hut u~'ti~lly ',gray orbtown, lllottleqabovewithgt:ay or da.rker.lines, and often 'with ohliqiIe' g~aya:reas on the;sidesoTheyfeed6Ilall :kinds. ofvegefation.·' They/trl,~y . hec.()n~ trolled,~ith ,commercially' ~prepare,cL ...

. .. 'Iloisonhaitsi The JJa~t~houldhe spattered' about llnderthe trees just before ,d,usk;.

LEAFMIN.,ER narro~, light-colored, .... se.rpe,n!ine'

pattern on, the greeritwigs of . av~c~do trees, and: oCGasionally on the foHag~mld fruit,hidic~t~s'tlI()' presenceofa letif

T261

\

Fig.· '. . .......• ' ....

)Al1pvEl: serPcEl!itin!lrnlnes .' and i.[la i:eaf(rightJ;.be\aw,

···mine,.gredtlyeh\q~ged. .

~,; ,-~':: ~;C!'}I~;;,~:JS~~,::'~: ·"'·':",,·:~,;,,7}:/?f:~:~:._;~:··/:i;:':j;_" ,>~,.~,/,<,',/-;;)" ',- -,; ""'/ ,\.",' " i<" X:';~ j:;" "::;;-7,':' '\:2i~~:~:~i;~r::~ \(( _ ". _,,'" ... _. ~ < • • . __ . 0-:;'., ,..:'::i _< ",,,"<' -'. ~".;.

:':~-' -;"'1S\.:~\:, _':;:~;,,:. _{ ,::,:: __ ~ ).,{--:-;, _ ,,3 >"~·,;n...;... t~,>,',~:o">:' ~',.,~< ,'0.'"", "-!'~":~"("" ;:'/;:':~¥'

;; - .'';'', ',,,',': , ,:'," < ,'> ,'- '-~ :'\> ';'r~-

'.,' ;(£~tin& attacking.n~-WlyplaJlted'~voOad();;ci" (:; ;:';tte~sJnY~PtutatZo1l9ty·rhe~~;~reeil'Vef;;" 'Y,:,. " .pxot~cte<l<with·,Shingles,';The,beetle,lS; 'clinibedUPthe,~J:!ing1es apd!1tethefoliage"

",'adJqiningthepl,'lJutilid riotappear'io hei' , •• cl~!iibirig;"wthe~uJlJ{s.Qf.the,tree~.dJ\:f~/ " Jplthiag~hW~sh·.~aten.thathW~Sb' llotliD,' " ';: " c.ont!1eti /~j. ,' •• t e." ingles.T !'l'" eet e~ .

. ;,~et¢ 'effectiytllY,combFited ,withpot.son. bran mash spr~ad on iheground. arQun<I;, the tre~s. .. . . . . c'·

'B,RA~C~A~P'TvV,IQa,ORER .. ' . Occasi,oi\af ex.a~ple~ofsevei:e injiuy

. _loav~~ad{) trees'from.the nranch and,', .. : ~ •. twigboJer. PolycaoT/,con,lertusLeC~:mte,

have be(:nnotedsince the.earliest days of . th~· avoc~do ,industry. in California, The" '~bQrersleaye unru:istakiible signs of,thei:r . 'work and e~n ther«ifor~be readily 10- .'

tilted. The entrarices of fhe burrows, ~adeby theadultso:~ravoc.ado trees}are

. very .cpnspiCU()U8, for: the sugary sap {"dulcitol"}' .that exudesbeco1,1les ,flaky 'Or '

' .•.• !tiine;, 'JiiaTmarasitii,~t:llrtC~~~ns'Th~ powdery and. tutns. :white. (fig. 34 ) ; as. in small, feddishlarvaeoft~e$e .tinym~ths the 'case of inj ury. by orai:lge torttix. Jn~

". . . . . festedbranches aJ"e easily broken by whid; 'h()re:beneaththeepid~hriis, leaving the . Thi~beetle~ (fig. 3ft) is black with' c.!iarach;'rjiltiCinarkinglS (fig. 32 ) . Thtlbrownwing cases; cylindrical; and 14 to ..

;'.n!1tive l}ostoJihisspecies.isthewillow, . . . . '. , .. . ." .'. ··%in9hlong. The adults burrow into the ';andoccasionally:avocado tree~ growing. crotches or budaxlls' of native trees as

near w" illow. are rather heavily infested;· .., . . 'well as apparently all kinds of fruit and

• ~ althoug:h no' economiCally important ... . . .'.. nut trees in California and parts of Ore" .. 'daniagehasev~been reported. The work .' . . of-these leaf '.miliers,ismostco.mmonlygon. The robust, curve,?,whjtish lai'V'ae

;seerlin mirseriesor y:oung.orchaids, The :.insect is worthy of note here mainlybe~

dause ofthecuriQ!iityaroused by its ~arlOngs. on avocado or citrus. t~igs, / leaves, Qrfruits; .". .

"'f)AIlK~INGG~OUND' BEET~E .••.•. ' .. ' l'hese' shiriiIigblack or brown' beetles '. (fig. 33J;ofthe species Conioritis . .sub. pub~sc~nsLe Conte, are about ¥s inch longll,nd;.ar{lr~¢onled as. being inj urious to sugarheetf'insouthem <;alifornia. \

. They area nafivespecies that may fly into. ) pulfivate4' areas from the srirtcJunding '. hills in-etlormous numbers. Ahoutthe

middle. of ~prir" 1949, these insects ,were

(2)7'1 , ,

Fig. 33~~Qarklihg grpundb~efles.(x3)

\

fohatehun,dl"~dsoft;e~sin'<~'~ngJ~'.or~ . . . .. . . '.' ,?hard.1:)urjng'rhedayt h.eYl:itiiri>;w;intc;>

.,' burrow ,fartIie!,;,completelY !hinjngth¢' ijlesoilto ail~pthQfJl'om% incltto2 heattwood."· .' .... '" i9ches and r,eappea:r tlJ.e follo:WingJ.l~gh~. ·;ApFarently. the. ~nl}r.I)ractieal. control;' to resu$e theirfeediIig .•. ·· . . Ill~<.lsure.especi!llIy.sj:tl<;etltejn:festati,ons. Coenonyr;ha . teslacea{CaZi~i-);(:6.g.' . ar~so.l?poradic 'andunprediciable,is'Jq , 3q,lwttPln).occU1:S over a 'wide arc!liii . prune off and bllrn the ~:iI~ested h:t:aIlches CalJfornia .bh certainspecies'9£o:native or twjgs; Nathreorcultivated trees. in. vegetlltion, .'. includingwlld. buc~:;,v:Iieat. stIrrourid~ngaieas$h()~d,.be exariUnoo aJ.ld'rabbit bmsh.Itw:as~firstfoul}(I '.<>J.l for ,~ossibles(!lirces.'of reinfestaHon., .' avocad() .trees in an ~rchanl.2miles.

J'U'N'.E BEEll.E·S south of Fallhrook, Californi~,.in·F~bru; aty, 1946'. Here the beetle di4'severe

. Of the June be~tles·attac~i~g.a~ocadosj"'· darnage, stripping the foliage from young . the species Seticafimbriata Le Contea:vd,trees and complet.eiy.destr()yingl\srilall ..

S.altemata Le CQntea,re themost £amil-' "a~ocado .nur~eryhy feeding()n thehuds iaf,to·the avocadogr,ower~ They are. of newly buddedseedlmgs. T~eheetle ffound in practically any locality and at-. rea;ppeared in the same orchar.d th~~ol .. ' ta(:kmany trees and other crops hesides lowing year; as well as in neighh~r,ing: the ·avD.cirdo .. Thes~. $Pecies ... are 'rather' . orchaJ,"ds, and h~s. heen eteadily:inci:~alS=·. large and" rohust, $.fimbriatahein,g Y2ing the range of its feeding on avocados ••. inch. and S. alternala% inch fong; The inthefallh,rook area: since 1946., .......•... former is asmootll or velvety hroWD, Coen'onychatestaceahelonglS'l:othe' withlaintly striped.wihg cases {fig, 35, sanlefamily (Scarabaeidael asthe,$er-· •

. '. top) , whHe the latter is of a uniform sI!iny' ,ica heetles •. · b~t· is $ri.allerand~istinctlY' 'hr6wn coloi'. . '.' 'narrower. This beetle meas'Uresii:bout%'

lunebeetles ate most InjutiQus in inch in length and % inch i~ widthi.and yo'Ung orchards pl~nted near uncul- . approathesa rectangula:t'shape. ineon~: tivated land, They fiy in from' their trasttdthe broadly J)v~l shape of the .

. ,·.hreediiIg places '. in . untilled fields .•.. an.d Serica beetles, C' testacea is shiny yellow-, brosh)arid andeat.the·foliage~nthe ish hrownln color, ThisspeciesfirstM·.

'treesat ni~ht. They may cO:inpletely de·, :gins to feed on)l,vocado foliageverY,early

[28]:,

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, ~ "

' ... '.' .. '. be~tlefeedingona..Fig7 '.' .,' .... ,\" ". ,'. .• yri!Jrlg'av()cado.,(X L~B)' , ,"'. ' '. , .. ", ',"

'these heetles alsofetidi)ll tep,der .avo~ado ' " (hit~Ja~tiaTYorearlrRehJJ1la:ry)ap.d is foliag~ and could prohablydomucn'" " f()und .'ina:rPl'eciah,le numbqrs feT" only, damage. to 'seeqlings or 'young trees; In·' .

"'ahOl,ltanlohth. The'SeriCahe~tIesappear 'festations, to date, however; have been ," ,."'ahout3 Illonths l~ter;,but;the period '0.£ foul1dollIYll1olderprchards;,. .' , " ',their ,activity is Illuch)onger. , A spray of ,2 poullds 'of 51) percent"

, Cofjtrol. Allthretlsp~ciesdiscussed DDT wettable powder to HlO gallons waf Iclhove. ~re ,'readily cop.tioll~d with, .5 per used with success in the control. of: .the :ce~tDDT dust,.. Gontrol can he effeCted, hronze ~illow'ftea'heetIe in one .orchard; ,

, , 'hyapPl):l:rlg,thei;lll~tei:thedo,thef~liag~ 'W.pOW:deted >"deposit' builder" at·%·. pttothe"grQtfndhe:t:leath'thetree.' In ,'pourid to 100gallQns was added to in, ;ei~~case, the be,etlM get enough. DDT creaSe the deposit of DDT .

BAN DE" ',LEA BEETLE' . ,·ontb~irfee.t casthey',eraw1 i'houhQreSult ,.in tlieii< deaHl. Prohablythe " appticatiol1 'nf,thedu8t hoth on the tree and on the The handed flellheetle,Systima iae" , grp~na,would .insllre thehestresults. It ,niata (Say},"isa yellowish or hrownish, isilllPortant to. apply the inseeticide.inseCt lhto:l/5inch in length (fig.37).~ 'whe~the heetIes,first ap.pear" ~ot they can ~It has a reddish head and twolateralblack

.... dOnluch damage in' a few nights:' "stripe~oneach wf~gcover,.oneof!hese ';B' "';. ...... , .. , .N'· 'ZE' ,.W·.LLO' • ·.W"F' LE' A' . • BEE' "LE·~,borderingthehirler margin. This species.

av ·wasfouud~tta:cking newly pUmtei;l.avo. '. '.' The,b'r<,>nze wilIowflea' heetle,Di~lius " Gadotreesneiir F'illnlOre, CalHornia, in

. i'f;turatus (Fahricius}.,Is a small; m:etallic the· latter. parl'<if August, 19;1.9. The bee- , ·"hr~nzeinsect H~ in~lior l~ss in: .Ie'mgili. . tIes fed on the' fol,iage (fig. 38) and some:

#;occurs iIl'manyparts of North America . times caused the death of the.il1fested. ,an~ South Americca andiscommoD.' on '. trees. .'.'

,wilI()w . in New . Me:x:i~o, . Arizona, alld This . specie!! occurs lhroughoutthe "C.alifornia.lthas cliuseddamageto fen- United States. T4eheetIes lay their eggg., detshoots ofpruuetrees in California. on the host plants; usually near the .

,'lnJuly, 19~9,this,h~etle, waS found feed~ gl"ound: .. Aniong~he hosts are.'Various; ingopRvocadg fri,litsinanorchard near "" weeds, truck crops, and grap,<vines" and .'~ntaPaula,Cali£orni;i;causing .a. con- thep~ar also has been ljl'!ted as ahost~·· spicuousscaron the peel (fig.36,) •. About ·:Qte slender,\v'hitelarvaelive in the soil, 1Q: per .cent,of.the: fruit was affected. where they pl,lpate. , .. ,. . .,

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;'

Fig. 38.-lnjuryto avocado leaves caused by the banded flea heetl~. (x 0.3)

FULLER ROSE BEETLE The Fuller rose beetle, PanJ;omorus

godmani (Crotch) (fig. 39), is about % inch long and is a uniform pale brown. It feeds on the younger foliage of avo­cado trees and may at times do some damage to the younger trees. The smooth, elliptical, pale yellow eggs. are laid in

Fig. 39.-Fuller rose beetle. Above: adults; be­low, larva. (x 4)

masses under the bark, on the ground near the trees, or near the bases of smaller plants. The . legless white larvae live on the TOOtso£ various plants, and pupate in the soil. Because the adults are . unable tq, fly, it is possible to prevent their ascentbya,pplying a sticky banding ma­terial to thetrull-ks. '

If sticky banding material iS,used, it . should be applied pver an area coated with high-boiling point paraffin to avoid possible injury to the bark. However, the

. application of a 5 per cent chlordane dust is a simpler method of combating the pest and is very effective. The vegetable weevil,. Listroderes· obliquus Klug,. which also occasionally· feeds on avocado foli­age, may likewise be controlled by mea,ns of chlordane dust. Observe precautions in the use 0/ this material as indicated onpage 4.

ADALEREs·WEEVIL During the fall andea;rlywinter of

1949, newly planted avocado trees near Poway, San Diego County,were attacked by, adaleres weevils, Adaleres humeralis Van Dyke. The fema.les of this species are about 1h inch in length, with the·males somewhat smaller. These beetles arelight to dark brown with a grayish mottling on the wing covers of some individuals, The wing covers have rows of deeppunc­tures (fig. 40). The weevils feed on the foliage and terminal buds, and their feed­ing can result in the death of young trees, Since they do :riot fly, they may be kept off the trees by means of sticky banding material.

SEED WEEVILS Seed weevill'lare among the most im­

. portant pestsofthe avocado from Mexico to Panama,butno destructive species has been found in the United States. III California a species of weevil known as the broad-nosed grain weevil, . Caulo­philus latinasus Say (fig. 41), may be found in ,avocado seeds, but only after

.' they have fallen to the ground .. Itbores through the Totting flesh of the avoGado

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.... and ~nte:rathe seeit Hllas in a feW in­stances attacked av~cado s~~ds plallted ," ~nntirsery seed bed~ •. Tli,e. resultirig.see(l­lings are less thrifty ~nd may jail to" reacn. sufficient sizeforb~dding at the proper season. ..' .. . .. ', .

,ThebrOlid-nosed grain w~evil is about' <% .i~ch long, haS th~tyPical p:rolongea snout'.oMhe: weevils; and rCf!einbles'the well-knawn grallary weevil; Sitophilus granarius': (Lillnaeus )ialt~ough ·.darker' . °brownincolor. . . '

. .

'AMaROSIABEETLE$ . ..

OC6asiop:ally avocado trees that may appe#T .tohesomewhatweakened,. yet

" . yieldgol;nl cropsandarecommerciaHy desirable;, are attacked hy sroallbeetles that ,cause the trunk and large'rlimbs to be riddledwithsmallhQles. Specimens frombne infested tree were .foimd,to be small, cylirtdricaI, brownish to black am-

,brosi~beetles" X yleborus x'Ylo~raphus

... .4Il:J.-'An Aaaleresbeetle JlJ.,~rtl"",·. mer,aiis V'a.nDYkel, ,and bcitch of eggs~laidby bee~le;in captivity, Onc:iY9~ado leaf. (x 2~2~~' .

(Say) and MOTiarthrum sp_, the former (fig:: 42) beingthe more numerous of the two species; *, These beetles. infest many',' native frees in California. They often ex­tend their brood chambers deep into the

. * The beetles were 'identified by Peter Ting; at that tiIlle with the Division or Entomology, California, State Department of Agriculture.

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"If'lr,£f',I~U~I~:,""L"v":a, ,'~r~~cQ~s~Qital1y , in~ ~i: a\()CiaiiQ. Tireyhavegil'dled "

I."'I,I,",~I'C_.,_,", • Somehelievethe " .ants injure the" , " in prdei·tohr~pg , " al>.out 1l:','How_(&,;s,~p" ,upon I whichtliey' " feed. J1t~ aV6c!ii!o' tree "bleeds" copi~ ,0u.sly.wp;en ipjured, A Sper. cent chlor-

'daIle, dUBt,; applied· tQ the' .tf:unk .and,the , I s!)ila,bouttliebase ofiheliu:nk,haslieen:'

successfilllyusediI). the'~ontrbl' of diis • IJ)est: 'ObscrvA precitt/)tio~sin'the useal thisrnfIt,eru:zla,s iftdicq~ed or/, pqge4; ", .'; ..

',EUftOPEANBItOWN5~AII. " I Th~ EtIrope,anbro~Jisnail~ ll~li~fM~; ,

p'ersa(MiiIler:)"js,!1~estofcitru!!" !1I).d heai.1~podo{ ilif1;tre~sthe~'attack arid iIi' 'avocados, in the 'relatively ,hulll~d'aird

, , th~se~hambersthe.ycl,11tui~arlJrbsia c091, coastalare~ ,inCali£Qrtiia. The ' fllngi that servea~ food·for, tlu:darvae. In 'shells .. 'Qfthis,speci;es&fe I?£ a grayish.' vigorous trees' the flow ~f sap,dti)wns.out' yellowalld. hr~wncolor. \Vhen. fully de­

I,' the eggs and larvae. These, beetles' ate 'no ' ' veloped, the $hen~hlly~either five or four' , threat to healthy trees, butmay a(:ceierate andone~lIaHwhQrlsandarel inch. or ., the death of weakened trees. '<" ",', "mo,:eiJ;idiametet (fig.M) "'.', ' ,,', " , ,The beetles have been.controHedhY ,,on av:()cad()sth~ snails Jeed(Hltlie'foli~ , " applying' a"solution of5-percent DDT, agea~d, al~0<onth~bloI!S9m:s and v.ery " in ker()sei1e to the, j,nfested areas of the young frUit, CaUSII).g. scar$, , During" the'" ' ,ba~k by meansQfa pain:t'bmsh.' .late willte]; ~:Ilde.arly spring, IIu>ntbs.

',I ' . l\'lUch istheperiodw~eri:tliesnails;are' FIR~' ANT', the mostactiye, ,theyeim beeoI},t:r~Ued"

:'The fire ant; S()len~psis g~miriata (Fa~. hypOison btanniaslrscattered under the ',bricius)' ,(fig. 43)" varie$ ,in ,len~ frofu' trees, as recommended £()rcitms-~b()llt

%5 inch in the worker to, % inch in , I pound to anaver:age~size t'ree~ Duel<l;;. some of the wingeafor~s.Theworkers and. geese are otten all()wed to rU:Illoose '

, ate pale yellowish,' 01'. reddisItwithblack ,in avocado ,'orl,:hards , to .'" keep the 'sn~ils , " ahdPII1:ens. The winged £o'rnis'lllay beo£ under cO:Ilt)."olhy eating them. ' , "",' the sRl:Ile color as 'the'work.ef.s·orthey ,

'. ~rna'Y.be entirely shini:Ilgblackorel1t~relyRATS" red?l!lh, They are ,capableofstingi:ng TheprincipaJrodentpests ;f the'~v()- ' severely. " " " " ' ',. cado lireth,~ rats,. which feed on the·fruit.

§; 'gemin.ata:a.s wt(ll '~?th~subspecieSJ' Bntil,1950<thil rats' that, lIJ?pear t~hav¢" d?l1ethe ~?stda:I}l~g~ ar.et~osllbspe- " eIes: the ,roof. rat, Rattus, ra.teu;s 'l#ex.an,

'drinus( Ge()fJr?y), sornetime$ 'clinedthe AlexandriQeo:r, gray riJl;'(fig.45),and· the,hlackrattRattus rattus, rfi,ttus,;(Li:Il- ..

"naeps);The roof rat is the oI\e~9st Ij~ely " t9 o~cur, in the~voca~o orchar~tIt~lly' attalllan?ver~all leI\gth .of IS in:ches, with a, tail. measuring $.5 tttlO )nches> Its, weight',seldom: exceeds ,8 ou~ces.Jt

r

;

'"

\

,:)_)~i,~ ~~(~~~.~;·.::':Vi~:::" -:v.',:' ~'~:y i'~I~ :~~:'~,:1\1~~~}~"~:{?, ,'L;;~~~'i5~' ;~:";~:;1~?,,~e~\:~~~o~; :,/~::~i(~~<~/~:;;:~< s :~}' .,;,::' :~~.,;', < ~\ ' '~ ~ <~ ,r ~':r :<: .•.... ' ..... ;~;;,i.;I!' .:~>~~;/ " "',_"'! :(:~·::"T~{::/{,,"<~ .. ~·)~, ",~, .. ',":;".:,1 ;tC:;.:" ".,/;',' .;< "'>

",;:,';' _ _",,,".! ",' .,' :~J'-{\':'\;'., "~<~';<h- '/"', " .. >.,:>:1 ;","«'{< ",",'-,

\:.~~'\:~-:",- >,,",,<,';~\':' ::', . "',,"',<.:> '~":i<;"{~"<-"'''''' <- :,>~il;,~.:,'. '<;':: ;", " " :,»." ,

~;;:;;:;'~'. :;;JI: ~¥ia.~b~fp;apd ~lexfaer:rio;;;;~~¥~i~i~i:"':~rith~AyJc~a~o;gr~wersjof[e~)~iv~~ dc~a.~;.··>,. ,i.., ·.ears,witij litt1¢.o.l: ;p~hl!~1i; )and}~thi~;;siQn.·t9 pile br()~eIl,avoc;~.olinU:i~:~n;,,<~·

l;:i'~ i " ~ape~i~g,;scaly:.taiJ.·~hi~h·}s{iY~pst;iil~\ i'v~r;iouspl~ces1ht0)Ighouiili~ .o~cnar<l,.,;' '.1. '.' way~lQI!gert;lllgl thi!h,eadap:dbodyc()ul":i fQf,~tiiltillage ". iSlnofpf,~cticed;'Thes!r

.. (',~' " .;,hine~:;· Thi$'suhspecies:.has :a,g~liy:'o~;.. a,ttor,d ideal ne~~ipg.places for <the rats ... ' ""gray-brQwn bilCkap9 srues;ap:athe hellt 'There~;yatofdpesew~Qdpiles, espe, / 'f'iis:wWteor .. ne~rly white.. .• " ......•......... cially w~entheyar~scatteredthToughout .• ';V" '\' ' .•.•. '. ,Theroofrats haveah0!lt6YQun:gper .. , th.e.orcha;rd,~a9he a: great . help. ili the. "',\::ff :' ·.··,hro;od. ~a Jnayb~e~.'s.eyeraJtjmeg: a ,rat·.copttoF prog~~.iE,rnPtyhoxesaIld

. " ye,ar . Jhey;inlilibiti h<lth~astt4im<lin~ ·.·scraps of . Jllm.~~~·'Sllould ". be;piled . co~~ ' . .land 'areas· .. in.~aJ.~fQrtiU:i:lnq.~.~~. found .. '."!lactiYalld'p.eli\tlY(qIl·. trestles Or bther in~l"al dis~ticts . as welball ip citi~s ;in .'. "8UPPOrtS$o t;lSfo ,k~ep th~ma . foot iC?T" .

. .' fact, this $uh~pecit)S' ha~been . found. in' ··moriab(jvetheground~. Fir,ew()oq should, ,Ilmll;l,' n:urilb.ei'S iIi'themountainsl!Sh~gh'~ hepiledjnsepal'ilted tiers.Garb~ge 'and' · as'~;OOO .feet.e1evation •... :rhey~!ef9qnd/scrapso~· edibl~·Ina~eI:iafshoula be kept • in.hQuses, ·wareholls~s;:feed!!t9rell;~~(:.r: in/111o~eaeans . or; . destroyed ·'Pt:olllptly.i

". ,.likeUrii N o~waY!l'B;t, lJut:al'e .. ' ~I~()fpui1d·. ,Ratlillrrowsm'ya,rdspr ij>outbuild~ngs ...•. . ()utdooris;so~ethnes}~:Ving:al~ri~s.~i'e~W~ y~nhe collaps~dhymeliill! of. a.pick,: .• · .. ):,anks; They are: g,qodcclimpe'fs., often c~()wbar, or sh6v.el. .'.. . <. '. '. '. ' ..

•. nellting in trees ~daenS:ehedge'sand~· . ,Trapping. Tr4pping is avery eHe<.:tive yiI\e~;. I' '., ." .'. .... . .' ' ... co~trolnieasilJ:e.Almostal1.r£oodthathll"·

~ Thelilack rat resembles the roof :tIif . mllnseat maybeused for bait. The,otdi" 'except' fo~ its almost.s()Udlyhlackcolor .'. naryspripg' snap trap, : in 11,' Jargersize. '. It is. {Olma only near §alf. water, such as . than thatllsed .lor m.ice,'appea,.rlltohethe ... inseap~I'ts and adj B;cent towns; but IUay mo!!t efIective .. \;ontraryfQ popular opih~ ' .. he foul!d in some ,Coasta1,avocadp or- iOli; nothing is gained,Ii;)' W,:eari;ngglQv'~s chards~ .:. '.' ...•.. ." .' '.' '. '. ". whensettingtraPllfoii;ats()X.;lI}rc~1 <>r.By

. In 1950, in S~Ii Dieg9Cotmty, there. Imili~g;'Vashing,or smokiirg1:lj.etvtliJ$tO .•. , w~ a particularly severe loss ofavocado remOVe the hllnianoaor;So~e,Sll9Pess, • . fruitcliused'h diunage frotnrats, f/lld it . will result if. the traps. ar!)set)md},aited was reported that the N<,?rway ;rat; Rattus .. ' / atonee.~Ilt tr appingisevell·:u:,:oie.ejiec~

, ; norvegi¢us-n~rvegic1J,S(Erxleben)· .. was '. tive if the t'rap!,ar~f placedlltitl p~ted, 'i ,

.the cqief 6fIender .. This is the'largest of· .. but leftunsetfor3 •... to,·Snig!tts ..•• befor,e' the. alien rat$, the ful1-~rown individu,al ,b¢ing·. again haited.arid Ilet •. By. this .time. .

.)eingabout 16inches long} wi1h.a7lh~ ,the ratshave.6vetcome their usua;l:{eaf i.nch tail,and ordinarily weighingaho~ut of a new obj ect.,In ~vocad()Qr~haJ;dllrats, 11 or 12 ounces. In contrast to the roof cim he trapped nearo,~ ulJ;~et wopdpiles, rat'and.blad~ rat; it 'has a ra;tijelbluntnear the trunks of trees • whetetheyhtty;e

• nose; andearsofOnly mbderatesiz~. The' .heen fe'leding on the fritii:;.:and .. iI1f8:ct;~n· . · :fti~ . is generally brown, with scattered' practically any location. ·Wh~nplac.ed.:on . '~black hairs, andill'darkest along thelllid~ the ground,the tllip'll1aybe:cpU;pfez:s,lfnr

dIe ofthe hack/['lieqnder ,parts, are pale .in the soil with ,thetrigger:'p:r.:ojl;lCijpg ....• graytoyelI~wish~hite .. The Norwa.y'rai: ' •.. above the: !>urfac~~ • For especi~lly~arY.,. has atehd.ericyiQ displ~(:e other species of 'rats, the'traps may he covered with fine .r~ts<whereyerit occurll and may possibly' soil or sawdill!t,so longa~ !he act~9~~f · hecotnerelatively :more important' as: an ··the trigger or spripg is D<!tadyerli!ely.af-

avocado pest. '. . ..... . '. . . feeted,. Somerats wiU.avoidexp61i!€ld ~ Sagitc:ltioft~ first .a:n10~g the control traPS, but can Beeau~htlfthetrapis

"'measures, Ilga;inst raill i,s,reduction of" shielded by aboard' (jr.hQ~,'.\'ith.lll'ace .. nestinga:p:db:r:eedi:rigpIaces toa rnini. . left for the-ratto'enter.

[341

\

" :;r·,~·:~'M,,",·~<y\t':; ::~:)::':;:~/"':~'?~ :,,;, ;',"r.;-' .,,/',;' ','}~,,, .

000 - ";;"<:~<' ": ,

· '0'0 POi~oljin~l.P9isQnilJglil\~i~ngobe~11 006[ht.~che$ .. ~4eya;enotoO so. ~~~y'asth~;~:" o $uCCess£UlIy.pracfi.Cea.l:Jyavoc~~gro~~ o·aii~n:ratsandcan readiIyb~ caughto:#io'o 0 •• ers 0 ~if,is 0 now 0 coming 'into :incr~asing 0 springO tat traps baited withroIJeil. oal$','i" .fa:Vor 'b~?allse .of the" greatosuccesll'·that ·peariJlt~utter,· raisil1,s,o or piun~s.,W60d~' has attended the use of the newpoisop rats, al\wdl a,s whiJe-ofootedmice,should;

.Warfaiin. On~advantage of thispois6il beohandi!!:ti'jrisuch'a way as 10. avoi;dget~:o • iso tha;t; it does not requireprebaiting.,·· ting live' flJas'o.r ticks on the d01:'lt,es ol;\ j

Alsoitis.notso poisonollstqhlltnans,as 0 skin, forthese maybe carriers of disease,; soJiIe6f thehoait!3 previously used. 0 •. ' Gloves should l;Ieworn"amlthe. cloth~ng ,

: . Grains, such as oatgroats, or any food shouldqe sprayed -with pyrethrun:l spray' o eaten byh1ill,IRllsmaYbe.used oas bait. The. immediately after these rodc:mts'arehan~ o· . poisoned bait in "bait boxes" is:pll;lced in dled~Therodentsshould be burned out~ .

10Coations that the rats are ·knoWn,tofre- doors, or blliiedto~ depthof2 feet. o qmint •. TIle bait boxes 'are left out sevetal The redfox squirrel, 'Sciurus ni~~r .days . and·thepoisonedbai~ is renewed m{iv.enter.( G~9£froy), is an' accidentally

.. ;until£~edirig.~el!.ses; S~veral qaysIl),aybe introduced species which now occurs i;r( . . 'required to killthe rats.' . .. ·norJhernl.osArigelesand Ventura coune

,Sinc;:e theadventof.Wada:rinas a rat ties.lt feeds on walnuts, avocados,and .' bait,many'&rowerswho' !(mnerlycon- oranges. It maybe trapped with an extra'"

'.' tr(jlledrats by t;r:IJPpiIlg are'n()'Yresorting large type o£tat trap placed in trees, .' . to.poisQriing.Inso:inecopntiesiti~ sold Meadow mice or voles (Microtus) are, at coWby the. county . . injurious hecause they gnaw the bark

, '.," ..' . '. • • 0

OlltER RODENTS

'and rootS of . avocado and,citrus trees that are surioundedby grass and weeds. '., Thejrrunwaysmaybefound in such loca~'.

'. Native wood rats,also known as~'pack .. ' lions. Mousetraps baited' with oatmeal,' rllts'\or"trade rats," are .also pests {lIthe rolled oats, or bits of apple or durot m~y .... av;ocado.Thespecies likely to be involved " be setin these runways with the triggers is the browD·£ooted woodrat;Neritom~()£ the traps across the runways. Mice luscipesBah:d" which, inhabits the foot- running in either direction can then be hills • and lower mountains; . This . species trapped.' When large numbers' of mice'

, has a· body 7 or 8 inches lorig and a tail are present, it may be advantageous to 6.5 to 7.5 inches long. It has' a blunt nose,poisonthe:in. Strychnine on alfalfa leaves slightly haired ears of mediull! size, or,rolled barley has been used, or zin,c biownfur, a:h~ moderately haired tail. phosphide on rolled barley 0;1'oat8 .. This rat builds large~ coni~al nests of . Pocket gophers (Thomomys spp.) are sticks ~ndJitter on the ground orintrees destructive to young avocado trees, and .'

'. andso:inetimes in buildings. . '. their control' demands continuous vigi-W ood·rats. will eat avocados, hut a lance on the part of the grower. TheiJ:'

morf) serious damage results from their presence is indicated by a series of feeding OIl the bark:; whichsometirpes ~ounded·sur£ace mounds. Theya,re con­r(lsults in the complete girdling and death troned· by trapping or poisoning .

. " ' . . . .

· . In order th.at the informatioriin our publications ~~ybe more intelligible, it is sometimes necesslll"Y' to use trade names of products. and equipment rather thail complicated descriptive or chemical. ·identifications.In so d.oing, it i1;1 unavoidable ins~Ple cases that similar products which are on the

: niarket underoiher trade names may nllt be cited. No endorsement of named prod.ucts is intended nor is criticism. impli~d of .similar products which arllnot mentioned •

. Co.oper.-adve Extension w.orlt.'in AgrieU:lt~l'~ and ~ome Econoin:i.~s. College of Ag;ie~ltul'e, University of Ca,1i(1)rrtia. and:Unlted Sta~'Depa~tment of,~rie111ture c:~.perati~g. :nirnrlb,ute!l in fu~he.ran.-ce of the Aets of Co,nsreo ~f May, 8, ,And June ~O. 1914. J. Earl ~ke~ Directpr, California A~~~lt~at;E~~~B~~n s~l~e •.. ' '

'lOm,5,'53 (AS080)J,B:

.[ 35]

Adaleres weevil ...................... : .................. ' '.'.

Amorbia ....................•..... ; ..... : . Aphids ..•... " ................... " .......... " .... : .... " . Avocado brown,mite . ; .............. '; ; ........... ; .... , ..... '. Avocadobud mite ... , .......... ' .... ' ....... , .•. ;., .•..... , ... .

Banded flea beetle ., ........... ' ............... " .•... ' .... ~ •.. ' ,' .... "'" .. , . Branch and twig borer .................. : .............. ; ...... ,,' ".;,.' .. Broad mite ................. , ......••....... ' ...... ", ...•.. , .. ' ..•.... , Bronze willow flea beetle ., ........ ' ............. ; .' ., ................• '." Darklinggroundbeetle ................... , .......... , : .... , .........• European brown snail ................................. .

False chinch bug. , .....•............. ; .. , ..•....... "', "'0" •••••••• ,".; •••

Fire ant .......... '. " ........... ; .... ; ' .... , ; .......... ; . Fuller rose beetle ................•........ ;;, ... ; : ", ,.,:. Greenhouse thrips ..... ; .............. ; ....... , . ' •... Greenhouse whitefly ....................... ',,' ..• ,' ..... ,\ •. ' "0':" o ••

Harlequin bug ............. : .... ' .... '" . . ... . .... .•.. ", .,.:. Holcocera ........... ' .......... " .... , ... '. ;, ........ ' ......• '. June beetles ......................................... ' ... ' ....• ; ....•. '.

, Latania scale ...............................................•.... ; ... 17 Other armored scales .. ' .....•.•..... 0 ' ••••••• : ••••••••••••••• ; ••••••• 18

Leafllliner ......... , ...................... ', .... .' ......... ' ........... '. 26 'Long-tailed mealybug ................................ " . . . . . . . . . . . . . .. 16 Omnivorous looper ..................... ; ........ ' ................. , ',' 20 Orange tortrix ............................................. 0 • • • • • ••• 25 Pallid mite . . .. • . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8, Platani mite .... :,,: .. " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8 Rats ... ;......... ''Z ••••••••••••• , ••••••••• " •••••••••••••• 32

Other rodents .:., ..... , ; ... : " ....... ' ..... , ........... ,' ............ 35 Seed weevils ..... , .. ; .................................. ; ..... ; .. 0,'" 30 Six-spotted mite ...... 1' ••••••••••••••••••• ' •••••• " •••••••••• ; • ' •• ; •• • •• 5'

Snowy'tree cricket ..... 0 ••••••••••••••• ; .' •• '0 ••••••• o. • • • • • • • • •• • • • • •• 9 Unarmored scales ................................................... 17 Variegated cutworm ... " ... ',' ....... , ........................ " ...... 26

I

~

\ <:I1E'Il,C;JlltRT(

c)nt"e inside p.g"sOflhi.s~~icdsectionis a quick reference chart ' , , , of p.s~saHackinga;'ocados, 'together with .. ecommended cont:roIJ~ •.. measures. T,hechar;t'maybe lifted out of the circular and hung on,a""""

>wcilll asiahandygU'ide.

\

PEST

Six-spotted mite

Avocado brown mite

Broad mite (in greenhouses)

Greenhouse thrips

False chinch bug

Harlequin bug

Greenhouse whitefly (on nursery trees)

CAUTION. Insecticides a proper precautions as ind attending the use of paratb it is likely to be used expe be applied by anexperienc

Fifteen per cent Aramite wettable powder at 2 pounds, 25 per cent wettable powder at 1 % pounds (or 25 per cent emulsifiable solution at 1 * pounds) to 100 gal­lons; 50 per cent Ovotran wettable powder at 1 pound (or 25 per cent emulsifiable solution at 2 pints) to 100 g~UoRs;46perc-ent$ulphe1lOBeWetk:lble powder:at 2

'. pounds (or.25 .pericememliifsiJiable.sOlution :at.3.piDt~} to 100 gallons.

Sulfur dust.

Sulfur dust (several applications).

Fifty per cent DDT wettable powder at 2 pounds to 100 gallons or 25 per cent malathon wettable powder at 2 pounds to 100 gallons.

Five per cent chlordane dust.

A 0.75 per cent rotenone dust or 10 per cent sabadilla dust.

Light medium oil at 1 ¥.z per cent with nicotine, pyreth­rum, or DDT; or 25 per ceQt parathion wettable pow­der at 1 pound to 100 gallons.

Long-tailed mealybug (on A slurry of 50 per cent chlordane wettable'powder, at scions of newly grafted trees) 2 pounds to a gallon, painted on the top of the grafted

Scale insects

Omniv.orous lOOper

'., .,.trunk. Qr limbaod dOW!),jhe sides forA,ios:hes.,

Two percent light medium summe~~~r9)tpi! e!p!.!,l~~~in~ Twenty-five per cent malathon wettclljle:' p1SwClerat 3

, pounds, tp 1.00 gq~lons!,lJlqybe,.u~E)dqgqinst Ja~ania scale andsoff scc:de.' '.' ii· . ··...i''>'

rb" ':;':'.-~,> ,. :;::;' . " ' .~ ;~,.:f,. .,. ':~<\:' ?:;;',(7

.Fifty::per eenf'DD.r· wettablepowdeiat:]zpou.nd: to 100 gallons, Double the dpsqge,jf, ~9mr~ iB9f grften~ouse thrips is desired.' ,

\

poisonous to humans and shoUld be used with ~ted on page 4. Because of the particular hazard 11, it is recommended that in the few cases in which (!Dentally in the control of certain avocado pests it it commercial operator.

:'[

PEST

Amorbia

Orange tortrix

. , Var.iegai'ed;ctltworm ·;(Qt!l~_l1S'ItFees)

Darkling ground beetle (on young trees)

June beetles (on young trees)

Bronze willow flea beetle

Fuller rose beetle

Adaleres beetle (on youn~ trees)

Ambrosia beetles

Fire ant

Argentine ant

European brown snail

Rats and gophers

TREATMENT

As for omniyorous looper.

Fifty per cent DOD weHable powder at 2 pounds to 100 gallons .

. ;Poisonhttit:~atteJ:edbeneatbtFees •

Pojson bait scaHered beneath trees.

Five per cent DDT dust.

Fifty per cent DDT weHable powder at 2 pounds to 100 gallons.

Five per cent chlordane dust.

Apply sticky banding material on trunks of trees.

Paint affected parts of trunks and limbs with 5 per cent DDT in kerosene.

Five per cent chlordane dust.

Five per cent chlordane dust or "a slurry of 50 per cent chlordane weHable powder applied to trunk.

Poison bait scaHered beneath trees.

Trapping, pOisoning.

Spreaders~ Avocado leaves are wet with difficulty_ The most effective spreaders should be added to the sprays at concentrations required to wet both sides of the . leaves adequately with the particular brand of spreader being used.