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4 ABSTRACT Henneberry, T. J., Briol, L. A., nd Kittock, D. L Integrting Methods for Control of the Pink Bollworm nd Other Cotton Insects in the Southwestern United Sttes. U.S. Deprtment of Agriculture, Technicl Bulletin No. 1610, 45 pp. A socilly, environmentlly, nd economiclly cceptble control method for the pink bollworm, Pectinophor gossypiell \Sunders), in the cotton-( Gossypium spp.) growing res of the Southwestern United Sttes is essentil to the further development of n efficient, effective cotton pest mngement progrm. The results of reserch studies conducted from 1972 to 1977, nd reported in this bulletin. identified nectriless cotton types nd selective termintion of lte-seson cotton fruiting forms s potentil components of n integrted system tht could provide cceptble pink bollworm control. The nectriless chrcter in cotton reduced pink bollworm infesttions pproximtely 50 percent s compred with infesttions in nectried cotton. During one seson, in conjunction with creful monitoring of cotton bolls to estimte n estblished economic threshold of 10 percent infesttion, only two insecticide pplictions were required for control, nd cceptble cotton lint yields were obtined. Additionl benefits from the nectriless chrcter were 37 to 57 percent reduction in Lygus spp. nd 8 to 66 percent reduction in cotton lefperfortor, Buccultrix thurberiell Busck. Dely or prevention of insecticide pplictions erly in the seson for Lygus control reduces dverse effects on beneficil species regulting H eliothis spp. popultions; however, totl predtor popultions in nectriless cottons were lso reduced. The reson for these reductions nd possible chnges in prey-predtor rtios nd their interctions need further detiled study. Insect predtor popultions were high in My, June, nd mid- to lte July, decresing in August when pink bollworm popultions re incresing. The role of insect predtor-prey interctions erly nd lte in the seson lso needs further study. The use of plnt growth regultors to remove lte-seson sources for pink bollworm oviposition nd. lrvl food to develop n overwintering genertion of the insect consistently resulted in more thn 90 percent reduction in the dipuse lrvl popultion t hrvesttime with minimum effect on cotton yield. Additionl methods tht might be used with resistnt cotton nd chemicl termintion re, in ech seson, pheromone trpping or pheromone confusion, judicious use of insecticides during the growing seson nd, in lte seson, erly irrigtion cutoff, nd culturl methods such s' erly plow down, winter irrigtion, nd crop rottion. If pplied over lrge re, these methods could provide the pink bollworm control necessry to develop n effective cotton pest mngement system. KEYWORDS: Pink hollworm, cotton insects, cotton integrted methods, resistnt cotton vrieties, plnt growth regultor, cotton smpling, cotton yield, cotton qulity, pheromone, gossyplure, hexlure, chemicl termintion, culturl prctices, beneficil insects, predtors, nectriless. For slile h~' tile Superlntendcnt of Documcnts, r.;.~. GOl"cnmcnt Printing Office WlIslllngton. D.C

5 CONTENTS Introduction...1 Melolnd. Clif History of the pink bollworm in the United Sttes...1 Nectriless cotton nd chemicl termintion in commercil grower fields, 1975 nd Literture review Generl methods... 6 Procedure Smpling for pink bollworms in bolls Results nd soil smples... 6 Pink bollworm mle moth trpping... 6 Chemicl termintion nd cotton defolition on commercil grower fields, l Sweep net nd D-vc smpling... 6 Procedure Plnt growth regultors...6 Results Cotton yields... 7 Overwintering pink bollworm moth emergence nd popultion development In-seson insecticide control nd selective Nectriless cotton nd chemicl termintion experiments in 1976 nd 1977 t the University of Arizon Agriculturl Experiment Sttion, Yum, nd Arizon Stte University Experichemicl termintion of lte-seson cotton ment Frm, Tempe...23 fruiting Procedures (Yum, Ariz , 1977) Procedures... 7 Results Results... 7 Procedures (Tempe, Ariz., 1976, 1977) Chemicl termintion, 1974 nd Results Prker. Ariz., Discu$sion Indio. Clif Literture cit~d PAGE This pper contmns the results of reserch only. Mention of pesticides does not constitute recommendtion for use, nor does it imply tht the pesticides re registered under the Federl Insecticide, Fungicide, nd Rodenticide Act s mended. The use of trde nmes in this public60n does not constitute gurntee, wrrnty, or endorsement of the products by the U.S. Deprtment of Agriculture. Issued July 1980

6 Integrting Methods for Control ofthe Pink Bollworm nd Other Cotton insects in the Southwestern United Sttes By T. J. Henneberry, L. A. Briol, nd D. L. Kittock' INTRODUCTION Since 1967, the pink bollworm, Pectinophor gossypiell (Sunders), hs cused serious economic losses to cotton-(gossypium spp.) growers in Arizon nd southern Cliforni from reduced yields nd qulity nd incresing costs of insecticides (49).2 Hevy relince on chemicls for control hs resulted in spordicheliothis spp. outbreks nd incresed problems with cotton lefperfortors, Buccultrix thllrberiell Busck (14). Preliminry dt indicte tht pink bollworm popultions from cotton grown in the Imperil Vlley, Clif., re more tolernt thn previously to orgnophosphte insecticides (H. T_ Reynolds, personl communiction). An cceptble method of control is n importnt first step towrd development of n effective cotton pest mngement system in production res where the pink bollworm is problem. HISTORY OF THE PINK BOLLWORM IN THE UNITED STATES The insect ws described by W. W. Sunders in 1842 from specimens dmging cotton in Indi. It pprently reched Egypt in infested cottonseed shipped from Indi bout nd ws introduced into the Western Hemisphere between 1911 nd 1913 in cottonseed shipped from Egypt to Brzil, Mexico, the West Indies, nd the Philippine Islnds (4)_ The pink bollworm ws detected in Texs cotton in The SOUTce of infesttion ws trced to cottonseed shipped in 1916 from Mexico to Texs oil mills. The infesttions were pprently eliminted by the use of cotton-free zones nd extensive clenup mesures, s ws n infesttion dislhenneberry nd Briol re entomologists. Western Cotton Reserch Lbortory, Phoenix, Ariz.; Kittock is n gronomist, Cotton Reserch Center, Phoenix, Ariz. 2Itlic numbers in prentheses refer to Literture Cited. p.45. covered in Louisin in The insect hs persisted long the Mexicn border djcent to west Texs since In 1936, pink bollworm infesttions' probbly from windborne moths, occurred gin in the lower Rio Grnde Vlley of Texs nd djcent Mexico, eventully spreding to the rest of Texs, New Mexico, Oklhom, nd sections of Arizon, Arknss, nd Louisin by the mid 1950's. The first pink bollworm infesttions in estern Arizon were reported in The insect hs persisted there since tht time. At periodic intervls therefter, infesttions occurred in other prts of the Stte nd were suppressed through coopertive Federl, Stte, nd industry progrms. These ctivities were terminted fter the 1963 cotton hrvest. Pink bollworm infesttions were next found in Cliforni in the Imperil Vlley in Spred ws rpid through0ut southern Cliforni nd severe losses occurred by Infesttions 1

7 2 TECHNICAL BULLETIN1610, U.S. DEPT. OF AGRICULTURE were detected in the high desert res of Los Angeles nd Sn Berndino Counties in tht yer, nd four moths nd six lrve were fo'.1nd in the Sn Joquin Vlley ner Bkersfield. Although vrying numbers of ntive moths hve been trpped ech yer since 1969, lrve were not found gin in the Sn Joquin Vlley until At present, the Sn Joquin Vlley remins the only cotton-growing region in the Western United Sttes not infested by pink bollworm. The pink bollworm ws erdicted from cultivted cotton in northern Florid nd southern Georgi during It hs survived in wild cotton in southern Florid since its discovery in 1932 despite erdiction of wild nd dooryrd cotton hosts from tht yer to 1967, except for the period July to June 30,1949. From 1967 to 1971, these cottons ech yer were rogued in only one-third of the known infested re in southern Florid. Roguing ws discontinued in 1971, nd the insect con~inues to exist there. LITERATURE REVIEW Considerble mounts of bsic biologicl nd ecologicl informtion hve been ccumulted nd pplied in developing pink bollworm control progrms. No single control method is completely stisfctory. The possibility of combining number of methods into single control system ppers the most promising pproch. The reserch contributions of mny scientists hw demonstrted tht suppressive mesures cn be pplied nd hve impct on reducing pink bollworm popultions t mnv points in its sesonl cycle. Moths from overwintered pink bollworm lrve begin to emerge in erly sprin~, nd emergence my continue into the summer \ ). The first genertion is initited in squres in erly June hy moths from overwintered lrve (44). Limited vilbility of host mteril nd other fctors result in low reproduction during this period ((i). Appliction of dditionl pressure ginst the popultion during this criticl period of estblishment my be n importnt considertion in developing n integrted pink bollworm control system. Reserchers (2(i) lerned tht the sex pheromone (gossyplure) of the pink bollworm ws mixture of the geometricl isomers of 7,11 hexdecdienyl cette md tht 1:1 mixture of the (Z,Z)- nd (Z,E)- isomers ws the most ttrctive combintion in field trp tests. BierI et L (11) reported similr results. Two min pproches for use of the pheromone for control in erly seson hve been suggested: (1) Utiliztion of the norml behviorl response of the insect to rech the pheromone source. nd (2) inhibition of the norml behviorl response preventing orienttion to the source. In the first of these pproches. the insects re killed, trpped, or otherwise disposed of t the pheromone source. The ltter pproch involves prevention of communiction within the species, resulting in reduced mting nd consequent reduced reproductive potentil of the insect. Extensive studies hve been conducted to evlute the impct of relesing high levels of gossyplure in cottonfields on pink bollworm popultion development (24). The results indicte level of pink bollworm control ws chieved tht is comprble to tht currently obtined with insecticide tretments. Trpping with sex pheromone bits in the field hs been less well investigted; however, the theoreticl potentil of the method ppers to wrrnt further ttention (33). Neumrk et l. (3H) iii Isrel indicted effective control of pink bollworm infesttions using gossyplure-bited trps t rte of one trp to 5 h supplemented by insecticide sprys t predetermined popultion levels. Flint et l. (18) reported high erly seson pink bollworm mle moth ctches with dosges rnging from 50 to 109,350 Ilg of gossyplure per rubber stopper substrte. In test to mesure the efficiency of the gossyplure- bited trps, bout 43 percent of 515 rdio-lbeled, overwintered, relesed ntive mles were recptured in 15.4-h field contining 40 trps bited with 1000 Ilg of gossyplure. During the relese period, 2,313 unlbeled ntive mles were lso cught. The dt showed tht gossyplure ws efficient in cpturing mles erly in the seson, nd mle nnihiltion using pheromone-bf'ited trps ws potentil control method. Flint et l. (19) investigted the effect of erly

8 INTEGRATING METHODS FOR CONTROL OF THE PINK BOLLWORM 3 seson mle trpping on pink bollworm popultion development. The trp used ws 300-ml styrofom cerel bowl with four holes, 2.2 cm in dimeter, cut in the sides of the bowl. The inside surfce of the lid ws coted with Stickem"'. The uthors found tht pink bollworm moths frequently entered nd left the trp without being cptured. They incorported 10 percent dicrotophos (dimethyl phosphte ester of (E) -3 hydroxy-n,n-dimethylcrotonmide) in the Stickem to increse trp efficiency nd kill (bout 13 percent increse) those contcting but escping the Stickem. The mle nnihiltion field test ws conducted on the University of Arizon Cotton Reserch Center Frm, Phoenix, Ariz., in The frm hd 35.8 h of cotton, 26.1 h of smll grins, nd 18.8 h of lflf. Trps were plced in the field during April 29 to My 14 t the rte of 12 trpsl h on grid pttern in n crops. Trps were chnged monthly. Trp density ws incresed to 25/h nd 50/h in cotton only on June 3 nd June 13, respectively. During erly June, trps were removed from grin nd lflf fields. Trpping ws continued in cotton until Sept. 15. Weekly smples of 50 bolls were tken from ech of the 11 cottonfields, nd lrvl infesttions were determined by boll exmintion. Five Shrm trps (43) checked twice weekly were mintined from Nov. I, 1974, to the end of the 1975 seson to monitor emergence of overwintering moths nd moth popultion density during the growing seson. The totl numbers of moths cught in Shrm survey trps in 1975 were: Jnury, 1; Februry, 0; nd Mrch, 14. Moths from overwintering lrve begn to emerge in erly April when bout one moth per night ws recorded. Numbers of mle moths cught per night per trp incresed grdully therefter to pek of two in mid-my, declined to bout 0.2 in erly June, nd incresed to 1.5 per night per trp in mid-june. Approximtely 27,000 pink bollworm ntive mle moths (see tble 1) were cught during the seson (19). Rosette bloom counts indicted tht low-level infesttion ws initited in June, but only 0.06 nd 0.05 pink bollworm lrve per boll were found in June nd July, respectively. Only 9 percent of the cotton crege ttined 10 percent or greter boll infesttions during the seson. This is compred with 45 to 100 percent ttining this level of infesttion during the preceding three Tble I.-Totl number of pinl~ bollllorm mles! cptured month/.v in gossyplure:!.-bited Huber trps3 4 in cotton, smll grins, nd lflf, nd pink bollworm infesttions in cotton during 1975 t the U nit'ersit,v of Arizon C' 0 ttoil Reserch Center. Phoenix, Ariz. Pink bollworm lrve cptured monthly Smple My June July August - _ - -Sumbf:r _... Mles cptured 4, Rosette blooms (percent) 111 Lrve per 100 bolls 657 lin.july 47 percent nd in August 20 percent were moths escped from nerby rering fcility s determined by check ing bout 30 Shrm trps in ech of 8 to 10 fields Ilgirubberstopper. :lstickem covered lid contined 10 percent dicrotophos. 4AII crops 12 ih until June 3. incresed to 25 h on June 3 nd 50, h on June 13 in cotton. Trps removed from smll grin nd lflf in erly June. Note: Dshes indicte no dt. Source: Flin t et l. (lg). sesons ( ) with similr economic thresholds used for initition of insecticide tretments but in the bsence of erly seson trpping. The results of the mle nnihiltion test p pered promising but. s the uthors stted. must be considered inconclusive since insecticides were pplied to ll cotton in the experimentl re on the frm beginning on July 10,1975. nd weekly therefter to Oct. 6. The effect of the trpping progrm ws, therefore. difficult to interpret. During the growing seson. insecticides remin the principl pink bollworm control method. Growers often follow rigid 5 to '7-dy ppliction schedule. The number of insecticide pplictions cn often be mrkedly reduced by bsing need for tretment on economic threshold levels, using pink bollworm popultions in bolls (49) or by the numbers of dults collected in trps (45). Chemicl control will remin vitl component of cotton insect l!ontrol methodology during the growing seson regrdless of wht other popul tion suppression mesures re used. The incorportion of insect resistnt germplsm into gronomiclly cceptble cotton types, however. my help to reduce the number of pplictions

9 4 TECHNICAL BULLETIN 1610, U.S. DEPI'. OF AGRICULTURE necessry to prevent losses. Lbortory evlu tions of primitive cottons hve reveled number of lines tht hve significnt detrimentl effects on pink bollworm lrvl growth nd development (:Jo). In mny insect species. source of dult food is necessry for mximum longevity nd reproduction. Mny of these species, s is true for the pink bollworm. utilize plnt nectr s source of such food (34). In ddition. bolls of nectriless cotton grown in field cges hd pproximtely 50 percent fewer pink bollworm mines thn did bolls from nectried types (35). Although the potentil vlue of nectriless cotton in reducing pink bollworm infesttions ws reported in lrge field tests were not conducted until In n experiment ws conducted t the Bruce Church Frms. Inc.. Pru-ker. Ariz. (57). 'Deltpine 16' nd 'Deltpine 16 nectriless' cottons were plnted Mrch 20, nd 25-26, respectively, in four djcent blocks (eight plots of 4.05 h ech). Beginning July 12 nd ech week for 8 weeks therefter. 50 firm green bolls per week were hrvested from ech of seven smpling loctions in ech plot: three smples from 22- by 22-m re in the center of ech plot nd four dditionl smples from loctions midwy between the center nd the four corners of ech plot. The bolls were held in plstic sweter boxes s described by Fye (21) for 2 weeks, nd the number of emerged pink bollworms ws recorded. On Nov. 4. cotton ws hndpicked from row 18.3 m long in the center ru'es of ech plot to obtin yield dt nd to provide seeds for X-ry exmintion (56). Pesticides were pplied by the grower t his discretion but lwys to ll cotton in the experiment (see tble 2). In seeds of 'Stoneville 7A' nd 'Stoneville 731N' (nectriless) cottons were plnted (four plots ech, 0.5 h/plot) t the Arizon Stte University Frm Lbortory. Tempe, Ariz., on April No insecticide ws pplied during the seson. From Aug. 24 to Oct. 1, 50 green bolls per week were picked from 15.2 by 27 A-m center re of ech plot. The bolls were held in emergence continers, nd pink bollworm counts were mde s previously described. Also, four times, from Sept. 18 to Oct. 30, ll cotton ws hndpicked in 9.1-m length of row in ech plot to obtin yield dt. Seed ws X-ryed for determintion of pink bollworm dmge. In both yers. the men sesonl number of pink bollworms nd seed dmge on nectriless cotton were less (61 nd 39 percent in 1974, nd 46 nd 39 percent in 1975, respectively) thn in the nectried plots (tble 3). Seed cotton yields were similr in both cultivrs. The nectriless chrcter lso hs vlue inreducin&" other cotton pests. For exmple, Schuster et l. (42) found tht numbers of cotton flehop- Tble 2.-Men numberl of pink bollworm lrve nd percentge of infested bolls from insecticide- treted 2 nd untreted'deltpine 16' cotton plots t Prker,Ariz.,31973 Lrve per 100 bolls Bolls infested Smpling Insecticide Insecticide dtf:' treted Untreted treted Untreted Nllmbrr Numbrr PercC'ni PC'rcC'ni.July 10 < 1 1 < < 1 1 <: 1 1 2: Aug. ) ~ 4 b ~ 1 1 1:3 (j 9 < b 23 1 b 6 2H 14 b 50 4 b 21 Sept. 14 b b b 1:32 4 b b 168 2H h b b 64 Totl ~1~ b 658 ii Men 18 h 55 7 b 18 lmem; of H replictions. Mens not followed by the sme letter within ctegory in the' sme row re significntly different. Duncn's multiple rnge test (P=.05) :1plots treted on,july 5, , nd 24 with 420 gi /h chlordimeform; on,july :31, Aug. 7 nd 14 with 420 gi h chlordimeform plus 489 gi 'h monocrotophos; on Aug, 21, 28, nd Sept. II with 711 gih monocrotophos; nd Sept. 18 with 264 nd 1:32 gl h 6- methyl. ethyl prthion. IThe u thors pprecite the coopertion of personnel of the Bruce Church Frms.!nc.. in conducting this reserch. Note: Dshes indicte no dt.

10 INTEGRATING METHODS FOR CONTROL OF THE PINK BOLLWORM 5 Tble 3.-Men numberl of pink bollworms per 100 bolls, percentge of dmged seed, nd seed cotton yield in cotton from nectried nd nectriless cotton t Prker nd Tempe, Ariz., in nd PBW per 100 Seed green Dmged cotton Cultivr Loction bolls seed yield 1974 Number Percent Kg/h~ 'Deltpine16' Prker 'Deltpine16' nectriless do 4 b 1 b 'Stoneville 7A' Tempe 'Stoneville,3IN' nectriless do 43 b 9 b 2957 IMens within column nd within yer not followed by the sme letter re significntly different. Duncn's multiple rnge te~t (P=.05). 2Sesonl men, 8 weekly smples, 50 bolls per smple', 7 smples, 4 replictes. 3Sesonl men, 6 weekly smples. 50 bolls per smple. 4 replictes. Source: Wilson nd Wilson (67). per, Pseudtomoscelis seritus (Reuter), nd trnished plnt bug, Lygus lineolris (Plisot de Beuvois), were reduced bout 60 percent in plntings of nectriless cotton; however, popultions of certin beneficil insects lso were reduced. Benschoter nd Lel (10) found tht cotton lef perfortor moths lived longer in the lbortory on cotton with nectries thn on nectriless cotton with the result tht the nectried cotton hd lrger lrvl popultions nd incresed lef dmge. These results were corroborted under field conditions (25). In ddition,. numbers of Lygus spp. were reduced, s well s totl insect predtor popultions. The importnce of the effect on beneficil insects is unknown. Reduced numbers my occur becuse of reduced pest-host density or need for nectr s food source for the beneficil species. Nturl popultions of predtory insects on cotton in Arizon hve not been considered importnt in reducing popultions of pink bollworm since they re declining lte in the growing seson when the pink bollworm popultion is incresing (13), nd the feeding lrvl stge of the pink bollworm is completely within the boll nd, thus, protected from predtion. In lrge plntings of nectriless cotton, the complex of intercting rthropod popultions my chnge in fvor of those species tht feed predominntly on other food sources (insects, pollen, nd other plnt mterils) other thn nectr. The direct effect of reducing rthropod species tht feed on nectr nd the chnge in prey-predtor reltionships must therefore be ssessed in greter detil. Control strtegies cn be pplied effectively lte in the growing seson with mjor impct on pink bollworm popultions. Typiclly, cotton boll set begins in erly June nd peks in erly to mid..july. Bolls tht re set before lte August or mid-september, depending on geogrphicl loction, usully mture nd open normlly. Bolls set fter these dtes usully do not mture or they produce fibers of low qulity (9). Thus, most of the hrvestble cotton is produced by Sept. 1; however, the cottons presently grown in most res exhibit indeterminnt plmt growth chrcteristics. Cotton fruiting continues until frost nd pink bollworms develop in bolls tht my not contribute to yield but do provide source of pink bollworms to infest cotton plnted the following yer. Pink bollworm lrve begin to enter dipuse (overwintering form) in erly September nd by Oct. I, 60 to 80 percent of those found re in this form (47; L. A. Briol, unpublished dt). Kittock et l. (32) found tht the mgnitude of the lte fll (October, November) pink bollworm popultion ws significntly correlted to the number of immture bolls t hrvesttime. Mny investigtors hve recognized tht dipusing pink bollworms re vulnerble to mnipultions tht cuse mortlity nd reduce popultion development. The focl points for considertion, in ech cse, re destruction of the overwintering lrve or prevention of the development in lte-seson cotton bolls tht serve s source of oviposition nd food for the lte-seson popultion. Some frm prctices in lte fll nd erly winter tht destroy numbers of overwintering lrve re stlk shredding, erly nd deep tillge

11 6 TECHNICALBUILETIN1610, U.S. DEPT. OF AGRICULTURE (22, 50), winter irrigtion (39, 52), nd crop rottion (37). Vrious methods hve lso been proposed for reducing the number of developing dipuse lrve in the fll. Chpmn nd Cvitt (16) reported tht stripping ll fruiting forms from cotton plnts on Oct. 1 reduced the number of lrve in the soil by 75 percent. Adkisson (1) nd Adkisson et l. (3) found tht pplictions of defolints or desiccnts in lte August reduced sources of food nd oviposition for pink bollworms nd, subsequently, the number of dipusing lrve found in cottonseeds by bout 90 percent. Similr results were reported in Cliforni by Rice et l. (40). In ddition, Wtson et l. (48) minimized overwintering pink bollworm numbers by limiting lte-seson boll development by terminting cotton irrigtion on bout Aug. 1. Muney et l. (36) proposed tht selective termintion of cotton fruiting during erly September with plnt growth regultors would reduce numbers of dipusing pink bollworm lrve s relted to the number of immture bolls vilble nd hve the lest dverse effect on yield nd qulity. Briol et l. (8) nd Kittock et l. (30, 32) confirmed this in field tests in The need to develop system of pink bollworm control tht integrtes severl of these promising suppression technologies into single mngement system prompted the initition in 1971 of the investigtions report in this bulletin. GENERAL.METHODS Smpling for Pink Bollworms in Bolls nd Soil Smples In our experiments conducted during , pink bollworm popultions in cotton bolls were determined by weekly picking of 50 or 100 (depending on plot size) firm green bolls from experimentl plots. Boll smpling usully begn with vilbility of first pink bollworm susceptible bolls in erly July nd continued for s long s bolls were vilble or until cotton ws hrvested. The numbers of pink bollworms were determined by (1) counting exit holes nd cutting open the bolls to exmine for lrve (cut-boll method) or (2) the incubted boll method offye (21). When the incubted boll method ws used, ll lrve tht cut out of the bolls nd those found in the bolls were counted, collected, nd held in petri dishes contining moist tissue pper. The insects were exmined t :intervls therefter over 4-week period, nd numbers of dults, pupe, nd live nd ded lrve were recorded. Living lrve remining t the end of the exmintion period were considered to be in dipuse. To determine the number of lrve in soil nd trsh in the fll, soil smples of 1 m 2 by 15 cm deep of cotton row were processed in gin trsh mchine; nd the numbers of insects were recorded. All fruiting forms on the plnts in the soil-smpled re were lso exmined for lrve. Pink Bollworm Mle Moth Trpping Where ppropite, Shrm- (43),or Delt (20) type trps, bited with either 25 mg of hexlure (28) on cigrette filters or 1000 IJg (18) of gossyplure on rubber stoppers, were locted in cottonfields to monitor mle moth popultions nd study sesonl distribution. Lures, in either cse, were renewed every 2 weeks. When Delt trps were used, trps were replced when 100 moths were cught. Trps were checked twice week. nd the moths were counted. Sweep Net nd D-vc Smpling Insects were monitored weekly in experimentl plots by tking 25, 50, or 100 sweeps, depending on plot size. with stndrd sweep net. In ddition, D-vc (suction mchine) (17) smples of two 15-m sections of row from ech plot t ech loction were lso tken weekly. In ech cse, numbers of L_ygus spp., blck flehoppers (Spngonicus lbofscitus {Reut.} ), Emposc spp., cotton lefperfortor, cotton flehopper, wsps, Nbis spp., Geocorisspp., Orius spp., Coccinellids, spiders, Collops spp., nd Chrysop spp. were recorded. Plnt Growth Regultors The effect of the ppliction of plnt growth regultors on cotton fruiting forms ws deter

12 INTEGRATING METHODS FOR CONTROL OF THE PINK BOLLWORM mined in either or both of two wys: (1) flowers, smll bolls, nd lrge bolls were counted weekly on ll plnts in six to eight rndomly selected res of 1 m of row in ll treted nd control plots nd/or (2) the numbers of green bolls in ll treted nd control plots were counted in two 15-m rndomly selected row smples per plot t hrvesttime. Cotton Yields Cotton ws mchine (spindle picker ) hrvested. Usully, four to eight rows per plot were picked. Cotton ws weighed, nd subsmples were tken for qulity me.surements, lint percentge, nd trsh content. Overwintering Pink Bollworm Moth Emergence nd Popultion Development Pyrmid moth emergence cges, 1.8 m 2, were used to determine effects of the previous yer's tretments on numbers of pink bollworms emerging the following spring. Cges were plced in the field s soon fter cotton plnting nd seedling emergence s possible. Cges were checked dily except for weekends, nd the numbers of moths emerged were recorded. In some experiments, Srn screen-covered field cges (3.6 m by 7.3 m by 1.8 m high) were lso plced in the plots over plnted cotton. Firm green bolls (50 to 75 per cge) were picked periodiclly to determine the spring pink bollworm popultion development s relted to the previous yer's tretments. 7 IN-SEASON INSECTICIDE CONTROL AND SELECTIVE CHEMICAL TERMINATION OF LATE-SEASON COTTON FRUITING, 1973 Procedures In 1973, test ws conducted on the Bruce Church, Inc., frm, Prker, Ariz_, to evlute the combintion of (1) n in-seson insecticide spry progrm to keep pink bollworm numbers t low levels during the growing seson nd (2) chemicl termintion of lte-seson fruiting to reduce the overwin:ering popultion. A 14.6-h field of 'Deltpine 16' skip-row (two rows plnted, one row not plnted) cotton ws rrnged in sp1it-plot design of 12 whole plots (24 split plots) of pproximtely 1.2 h ech. Whole plot tretments consisted of four replictions ech of (1) lflf looper, Autogrph cliforni (Speyer), nucler polyhedrosis virus (ACNPV), pplied weekly JUly 3 to Sept. 18; (2) scheduled ppliction of insecticides (see tble 3); nd (3) untreted control plots. Smples of 100 green bolls were picked weekly from JUly 10 to Sept. 26 nd were exmined by cut-boll method for pink bollworm lrve. ACNPV pplictions hd no effect on pink bollworm popultions, nd, for purposes of further nlysis, the dt from these plots were combined nd considered s n dditionl four untreted control plots. One-hlf of ech whole plot (bout 0.6 hl ws treted on Aug. 21 with 2,4-D, (2,4 dichlorophenoxy) cetic cid (0.028 kg ctive ingredient (i) per h), plus chlorflurenol, methyl 2-chloro-9-hydroxyfluorene-9-crboxylte (0.56 kg i/h), using high clernce ground spryer. Boll smples (50/plot) were picked weekly therefter from ll plots from Sept. 11 to Oct. 25, nd the numbers of pink bollworms in the bolls nd those in dipuse were determined by the incubted boll method. The field ws replnted to 'Deltpine 16' cotton in After plnt emergence, four pyrmid pink bollworm moth emergence cges nd one Srn screen-covered field cge were plced in ech plot to determine moth emergence nd popultion buildup in the field cges. Results The in-seson insecticide spry schedule controlled pink bollworms through Sept. 11. Infesttions were low in ll plots until mid-august ( tble 3). In the untreted plots, there were 0.5 lrv/boll nd 21 percent boll infesttion on Aug. 29. Popultions incresed rpidly therefter in untreted plots, reching bout 2.0 lrve/boll nd 64 percent infested bolls on Sept. 25. The lst insecticide ppliction ws pplied Sept. 18, nd numbers of lrve in bolls incresed in both

13 8 TECHNICALBUILETINl610, U.S. DEPT. OF AGRICULTURE treted nd untreted plots therefter. The results of the incubted boll dt (tble 4) indicte tht lower popultions existed in the plots treted during the seson with insecticide for severl weeks fter the lst ppliction s compred with untreted plots; however, lrvl popultions were incresing in bolls in ll plots. The percentge of lrve in dipuse showed rpid rise during September to 88 percent by Oct. 2 (tble 4). There ws slightly higher percent of lrve in dipuse in the terminted plots thn in the nonterminted plots in September. There ws no difference in the percentge of lrve in dipuse due to the in-seson insecticide tretments. The numbers of pink bollworm lrve in the soil nd in bolls nd the number of green bolls were reduced more thn 90 percent in chemiclly terminted plots (tble 5). There were fewer lrve in soil nd bolls in terminted nd nonterminted plots treted with insecticide during the seson thn in the controls. Lint yields were higher in the insecticide treted plots thn in control plots. Chemicl termintion did not ffect yield. None of the tretments dversely ffected seed or fiber qulity chrcteristics (tble 6 nd 7), but fiber strength, micronire, nd crding loss differed between first nd second cotton hrvests. Pink bollworm moth emergence the following spring (1974) ws reduced in the terminted plots s compred with those in the unterminted plots nd in ech cse ws less in plots protected with insecticides the previous seson thn in those receiving no insecticides. The differences due to insecticide tretment, however, were not sttisticlly different. These results re s follows: Tretment Med number of moths per hectre emerged CHEMICALLY TERMINATED In-seson insecticide treted....13,342 b Untreted... 17,534 b NONTERMINATED In-seson insecticide treted... 19,440 b Untreted... 28,970 lmens of 4 cges per pl"t, 8 plots untreted, 4 plots insec ticide treted. Mens in the eolumns not followed by the sme letter re significntly different (Duncn's multiple rnge test, P=.05). Tble 4.-Men number ofpink bollwormsl per 50 belis ~nd percentge in dipuse2 from chemiclly terminted nd nonterminted insecticide- treted 3 nd untreted fdeltpine 16' cotton plots, Prker, Ariz., 1973 ~- _~ Smpling dte.. ~~ _S ee~~..1?~.:... ~ Oc.!.obe~ Tretment Men number per 50 bolls Chemiclly terminted: 4 Insecticide treted 5 b 6 b 8 b 23 b be 23 b Untreted b b 35 b N on terminted: Insecticide treted 3 b 15 b 10 b 15 b 8 b 21 c 32 b Untreted b Percent dipuse frre Chemiclly terminted Nonterminted IMens within ech smpling dte not followed by the sme letter re signifi cntly different. Duncn's multiple rnge test (p=.05l. 4 replictions insecticidetreted, 8 replictions untreted. 212 replictions. 3See tble 3 for spry schedule durinb the growing seson. 42,4-D (0.028 kg i/hl plus chlorflurenol (0.56 kg i/hl on Aug. 21.

14 INTEGRATING METHODS FOR CONTROL OF THE PINK BOLLWORM 9 Tble 5.-Men} lint yield, number of immture green bolls, nd pink bollworm lrve in soil nd bolls t hrvest in chemiclly terminted,2 nonterminted, nd insecticide- treted 3 nd un treted cotton plots, Prker, Ariz., 1973 Immture Lrve in Tretment Lint yield bolls Bolls Soil ---~---- Kglh Numberlh Numberlh Numberlh Chemiclly terminted: In-seson insecticide 1,782 21,546 b 24,209 c 4,036 c Untreted 1,570 b 13,437 b 295,881 b 75,315 b Nonterminted: In-seson insecticide 1, ,668 38,332 c 11,433 c Untreted 1,412 b 272, ,043 95, ~~~ " IMen of 4 replictions; 2 15-m smples per plot for immture bolls, 2 soil smples of! m 2 x 15 cm deep of row per plot for lrve in soil nd bolls. Mens not followed by the sme letter within column re significntly different. Duncn's multiple rnge test (P=.05). 22,4-D (0.028 kg i/h) plus chlorflurenol (0.56 kg i/hl on Aug See tble 3 for insecticide spry schedule. Tble 6.-Men} seed weight, percentge of germi ntion, nd dmged seed from chemiclly ter minted 2 nd nonterminted insecticide- treted 3 plots, Prller, Ariz., 1973 Seed Tretment Weight Dmged Germi seed ntion (floters) In-seson insecticides: Chemiclly terminted: GJlOO Percent Percent Mens: 1st pick (10/30) c 2d pick (1215) b Nonterminted: 1st pick bc 2d pick Chemiclly terminted b Nonterminted JMen of 4 replictions. Mens in column not followed by the sme letter re significntly different, ccording to Duncn's multiple rnge test (P=.05). 22,4-D (0.028 kg i/hl plus chlorflurenol (0.56 kg i/hl on Aug See tble 3 for spry schedule.

15 ,.-~~ _._.- 10 TECHNICAL BULLETIN 1610, U.S. DEPT. OF AGRICULTURE (tble 8). There did not pper to be ny crry over effect from the insecticide spry schedule pplied during the previous cotton-growing se son. The chemicl termintion tretment in 1973 delyed the 1974 buildup of dmging popultions, nd the verge boll infesttions were significntly lower during the first 5-week period Tble 7.-Cotton fiber qulity mesurements} in first nd second cotton hrvests 2 from chemiclly terminted 3 nd nonterminted, insecticide- treted 4 nd untreted cotton plots, Prker, Ariz., ~-~ "~ Fiber _~~ng!j1. Gin Fiber Micron Yrn Crding Tretment turnout Lint Trsh percent percent strength ire strength loss --_._--- -~ ~--~--.---~- --~ _... --~..~----~ '--"-- Chemiclly terminted: In-seson insecticide treted: Percent 1st pick dpick 31.4 Untreted: 1st pick d pick 30.9 N onterminted: In seson insecticide treted: 1st pick d pick 30.6 Untreted: 1st pick dpick 31.0 Percent Percent n Mil/i meters Mil/i meters mii'/tex en/tex Percent b b b b n c c b ~~.-~ '~-----~-- ~-. lmens within column not followed by the.sme letter re significntly different. Duncn's multi pie rnge test (P=.05). 2First hrvest Oct. 30, second hrvest Dec ,4 D (0.028 kg i/hl plus chlorflurenol (0.56 kg i/hl on Aug See tble 3 for insecticide spry schedule. Note: Dshes indicte no dt. CHEMICAL TERMINATION, 1974 AND 1975 in 1974, nd Melolnd, Clif., in 1975 to more c curtely determine the optiml time of ppliction nd efficcy of severl plnt growth regultors. Timing is criticl considertion in the ppliction of plnt growth regultors to remove lteseson bolls without ffecting yields. Experiments were conducted t Prker, Ariz., nd Indio, Clif.,

16 INTEGRATING METHODS FOR CONTROL OF THE PINK BOLLWORM Tble 8.-Men l number of pink bollworms per 50 incubted bolls from cged cotton plnts in 1974 from chemiclly terminted,2 nonterminted, nd insecticide- treted 3 nd untreted cotton plots in Tble 9.-Effects of plnt growth regultors! on yields nd number of immture bolls nd pink bollworm lrve in cotton plots chemiclly terminted on different dtes, Prker, Ariz., July ~_ August Tretment Chemiclly terminted: In-seson insecticide Untreted < Totl 3 7b 16 25b 31b Nonterminted: In-seson insecticide Untreted Totl IMens nd totl of 4 replictions, 1 field cge per plot. Totls in sme column not followed by the sme letter re significntly different. Duncn's multiple rnge test (P=.05). 22,4-D (0.028 kg ilh) plus chlorflurenol (0.56 kg i/hl on Aug. 21 3See tble 3 for spry schedule. Prker, Ariz., 1974 The tretment pplied by ir on Aug. '32 or Sept. 4 ws 2,4-D (0.028 kg i/hl plus chlorflurenol (0.56 kg i/h). Plots of 'Deltpine 16' cotton were 1.2 h in size, nd there were four replictions of ech tretment nd four untreted control plots. At hrvest, lint yields, number of immture green bolls, nd number of pink bollworm lrve in 100 bolls/plot nd in soil, debris, nd bolls in two soil smples per plot were obtined in the mnner 'previously described. Tretment on either dte significntly reduced the number of green bolls nd did not reduce cotton lint yield ( tble 9); the Aug. 22 tretment reduced the number of lrve in immture bolls 98 percent, nd no lrve were found in the soil. In untreted control plots, 40,000 lrve/h were found in the soil. Tret Lrve in- ment Lint Immture Immture Soil dte yield bolls 3 bolls 4 smples 5 Thousnds Thousnds Thousnds Kg/h /h /h /h Aug c < 1 b 0 Sept b Control ,4-D (0.028 kg i/hl plus chlorflurenol (0.56 kg i/hl pplied by ir. 2Mens not followed by the sme letter re sttisticlly different. Duncn's multiple rnge test (P=.05). Ech figure is n verge of 4 replictes. 3Counts mde on 2 15-m sections of row/plot fter first hrvest on Nov. 4. 4Clculted from number of lrve per 100 bolls multiplied by the number of immture bolls per h; both counts mde on Nov. 5 nd Two I-m x 15-cm-deep smples of row. All replictes not exmined. Counts mde on Nov. 5 nd 6. Source: Brio!,) et l. (8). Indio, Clif., 1974 The experiment ws conducted on 'Deltpine 16' cottonfields of the EI Dordo Lnd nd Cttle Compny. Plots were 45 rows wide (bout 1-m centers) nd 399 m long in three replictions nd 197 m long in the fourth repliction of the experiment. One hundred green bolls were picked nd cut open weekly from ech plot from June 19 to Aug. 8 to determine the number of pink bollworm lrve present nd percent infesttion. In ddition, the numbers of flo~ers, smll bolls, nd infestble bolls were counted in eight1-m row lengths in ech plot, nd the numbers of pink bollworm infested bolls per hectre were clculted. Chlorflurenol (0.56 kg i/hl in 94 L of wter per hectre ws pplied by ir to four plots in ech cse on Aug. 23 or Sept. 5. There were lso four untreted control plots. Plnt dt s described were tken weekly beginning on Aug. 23 (the dy following chemicl termintion tretment) nd continuing to Oct. 8

17 12 TECHNICALBUILETIN1610, U.S. DEPT. OF AGRICULTURE to determine the effect of the chemicl termintion tretment on cotton fruiting forms nd pink bollworm popultions. Smples of 100 green bolls were picked from ech plot weekly from Aug. 23 to Oct. 16 nd incubted to determine the numbers of dipuse pink bollworm lrve. At hrvest, green L0lls were counted, nd soil smples for pink bollworm lrve were tken. Tble 10 shows tht pink bollworm infesttions develop slowly until bout mid-july, therefter incresing to bout 60 percent infesttion on Aug. 8. On Aug. 23, when the first chemicl termintion tretment ws pplied. popultions pprocheci three lrve/boll in ll plots (tble 11). The numbers of green bolls on the plnts t the time of tretment on Aug. 23 were not ffected, nd significnt reduction in fruiting forms did not occur until Sept. 16, 38 dys lter. Tretment on Sept. 5 did not significntly ffect the numbers of Tble 10.-Menl number per hectre of flowers,nd smll bolls. number of infestible bolls nd pink bollu.'orm -infested bolls. nd percentge of pink bolhcorm infesttion in 'Deltpine 16' cotton plots prior to chemicl termintion, Indio, Clif., 1974:2 Flowers Sm nd Infest PBW PBWpiing smll ible infes infested dte bolls bolls ttion bolls Thousnds Thousnds Thousnds I/w h Percent 'fw June July Aug IMens of 12 replictions; 8 I-m smples per repliction; 100 bolls per repliction for pink bollworm dt. 2The uthors pprecite the coopertion of the Eldordo Lnd nd Cttle Compny, Indio, Clif" in conducting this reserch. green bolls t the time of ppliction. There ws no effect on lrve per 100 bolls or percentge of lrve in dipuse. Squres, flowers, nd smll bolls, however, were reduced within 8 to 23 dys (tble 12) fter tretment, nd, t hrvest, green bolls were reduced bout 42 percent nd lrve in soil nd trsh smples were reduced bout 40 percent (tble 13). Lint yields were not significntly different. Melolnd, Clif., 1975 'Deltpine 16' cotton plots, eight rows wide by 402 m long, were treted with MCPA [( 4-chloroo-tolyl)oxy] cetic cid (0.028 kg i/hl plus chlorflmenol (0.56 kg i/h). Applictions were mde with high-clernce spryer on Aug. 28. Control plots were untreted, nd the experiment ws replicted four times. All green bolls were counted on the dy of tretment nd weekly therefter until Oct. 25 on ll plnts in ech of six I-m row lengths, rndomly selected in ech treted nd untreted plot. Green bolls (100) were picked from ech plot weekly from Aug. 28 to Nov. 7 nd were incubted to determine pink bollworm popultions nd number of dipusing lrve. At hrvest, immture green boll counts were mde in two 15-m row lengths in ech plot. Dipuse lrve in soil nd trsh were determined. In Mrch 1976, 10 pyrmid pink bollworm moth emergence cges were plced t rndom loctions in ech of the plots, nd the number of emerged pink bollworm moths ws recorded. The numbers of green bolls per meter on cotton row were reduced bout 70 percent 23 dys fter ppliction nd 100 percent 64 dys fter ppliction (tble 14). Lrve per 100 bolls nd percentge of lrve in dipuse did not differ in terminted or nonterminted plots. At hrvesttime, no green bolls were found in terminted plots, nd lrve in soil nd trsh were reduced bout 98 percent ( tble 15). Lint yields were not ffected by the chemicl termintion tretment. The numbers of dults emerging the following spring (1976) were reduced 71 percent in the plots chemiclly terminted Aug. 28 of the previous yer (1975).

18 INTEGRATINGME'lHODS FOR CONTROL OF THE PINK BOLLWORM 13 Tble n.-men l number of green bolls per meter, pink bollworm lrve per 100 bolls, percent lrve in dipuse, nd percent lrvl mortlity in chemiclly terminted 2 nd untreted 'Deltpine 16' cotton plots t Indio, Clif., 1974 Green bolls Lrve Dipuse Lrvl mortlity Smpling Treted Untreted ~Tr~eted Untreted Treted Untreted Treted Untreted,----- dte 8/23 9/5 (control) 8/23 9/5 (control) 8/23 9/5 (control) 8/23 9/5 (control) Number Number Number Number per 100 perioo per meter per meter bolls bolls Percent Percent Percent Percent Percent Percent Aug < 1 < Sept. 6 71b 81 7lb b o o < b < 1 < 1 < 1 Oct lmens of 4 replictions; 8 l'm smples per repliction for green bolls. Mens of 4 replictions for pink bollworm lrve, percent dipuse, nd percent lrvl mortlity. Mens within row for green boll dt not followed by the sme letter re signifi cntly different. Duncn's multiple rnge test (P=.05). 2Chlorflurenol (0.56 kg i/hl. Note: Dshes indi.:te no dt. Tble 12.-Men f number of squres, flowers, smll bolls, pink bollu'orm infestible bolls, nd hrd green bolls on chemiclly termirwted 2 nd control plots, Indio, Clif., 1974 Squres Flowers Smll <>olls Infestible bolls.h.!li'd_~eeil_bolis_ Un Un Un Un Un Smpling Treted treted Treted treted Treted treted Treted treted Treted treted dte 8/ (control) ,5 (control) (control) ;5 (control) 8/23 9 i 5 (control) ,~1en /lumber..... Aug Sept b 51 b b 14 b b 18 b 21 1 b b b b 5 b 17 <1 b b 13 7 b Oct. 1 2 <1 <1 <1 <1 1 b 3? 2 b 2 b 5 3 b <1 <1 1 <1 0 o <1 b <1 b 1 < IMen? of 4 replictions; 8 l'm smples per repliction. Mens in the sme row nd ctegory not followed by the sme Jetter re significntly different. Duncn's multiple rnge test (P=.05). 2Chlorflurenol (0.56 kg it hl.

19 14 TECHNICAL BUILETIN 1610, U.S. DEPT. OF AGRICULTURE Tble 13.-Men l number of green bolls t hrvest, kilogrms of lint, nd lrve per hectre in chemiclly terminted 2 nd nonterminted 'Deltpine 16' cotton plots, Indio, Clif.,1974 Lrve in soil Tretment Green bolls Lint nd trsh Chlorflurenol: No.ilw Kg/Fw No. h Aug ,508 b 1,340 6,462 b Sept. 5 76, ,846 Control 69,407 1,232 10,769 1Men of 4 replictions; 2I5'm row smples' replicte for green bolls, 2 1_m 2 x 15 em of row for soil smples. Mens in column not followed by the sme letter re significntly different. Duncn's multiple rnge test (P=.05). 2Chlorflurenol (0.56 kg i'h). Tble 15.-Men l number of green bolls, kilogrms lint, pink bollworm lrve per hectre t hrvest, nd number of emerged pink bollll..'orm moths the following spring in 'Deltpine 16' terminted!! nd control cotton plnts, Melolnd, Clif., Lrve ill Adults soil nd emerging trsh in in spring Tretment Green bolls Lint 1975 of1976 No..th Kglh No.lh No.lh Terminted 0 b 247 8,615 b 494 b Control 205, ,076 1,729 IMens of 4 replictions in column not followed by the sme letter re significntly different. Duncn's multiple rnge test (P=.05). 2 15'm lengths of rows smpled for green bolls, 2 l m 2 x15 cm deep soil smple/row for pink bollworm. 2MCPA (0.028 kg i/hl plus chlorflurenol (0.56 kg i/hl on Aug. 28. Tble 14.-Men number of green bolls per meter, pink bollworm lrve per 100 bolls, percent dipuse, nd lrt'l mortlity in terminted 2 nd control 'Deltpine 16' cotton plots tmelolnd, Clif., ~ -~.>-~...,----~------,.~~~-- Smpling Green bolls.'-. Lrve..._~_ Dip~~!:._...~ Lrv!i~~r.?lity~._ ~-"--.--,.-.- dte Terminted Control Terminted Control Terminted Control Terminted Control.., ~-~ ~,.-,-~-"""'""'.--.--". -.~-~-- ~-""'-"'-----"-----'---- Number Number Number Number per100 per100 per meier per meier bolls bolls Percent Percent Number Number Aug Sept \ b Oct b : b b b b Nov b ~----~~.---~-~-~-...-~-,-<--"~.. IMens of 4 replictions; 61-m smple per repliction for green bolls; mens of 4 replictions for lrve/ioo.bolls, percent dipuse, nd lrvl mortlity, Mens in row nd ctgory not followed by the sme letter re significntly different. Duncn's multiple rnge test (P=.05). 2MCPA {0.028 kg i/hl plus chlorflurenol (0.56 kg Lth) on Aug. 28. Note: Dshes indicte no dt.

20 INTEGRATING METHODS FOR CONTROL OF THE PINK BOLLWORM 15 NECTARILESS COTTON AND CHEMICAL TERMINATION IN COMMERCIAL GROWER FIELDS, 1975 AND 1976 Procedures In 1975 nd 1976, experimentl cotton ws plnted t ech of two loctions in Mricop nd Hrquhl, Ariz., on commercil growers' frms. In ech cse nd t ech loction, nectriless cultivr nd nectried cultivr were plnted in ech field in ech yer s shown in tble 16. Swee.~ net smples were tken weekly in ech field nd in ech cultivr beginning June 3 through Aug. 12,1975, nd June 1 through Aug. 31,1976. In ddition, D-vc smples, s described, were tken from June 3 through Oct. 14, 19'1'5, nd June 24 through Aug. 31,1976. Weekly smples of 100 green bolls were picked from ech of the plots of nectriless nd nectried cotton from July 29 to Oct. 23, nd July 15 to Dec. 30 in 1975 nd 1976, respectively. The bolls were opened in the field nd exmined, s described, for pink bollworms. On the sme smpling dtes, ll plnts in 4 m of row in ech plot t Tble 16.-Experimentl plntings of nectried nd nectriless cotton t Mricop nd Hrquhl, Ariz., 1975 nd Loction! 'Deltnd pille 16' 'Stone, grower 'Delt nectr 'Delt ville member pine 16' iless pille 61' 731N' Jiectures Mricop: Hrquhl: _~...,.."' 3 3 Men IThe uthors sincerely pprecite the excellent coopertion of Fred Enke nd Jck Plmer, Mricop, nd Jke Stephens nd Hrry Porterfield, Hrquhl, in prticipting ill these studies nd growing the cotton in the experimentl plntings. 28 h of 'Deltpine 61'. 38 h of 'Stoneville 213', ech loction were exmined for cbbge looper, Trichoplusi ni (Hubner), nd Heliothis spp. eggs nd lrve. In ech yer, three Shrm trps, bited with hexlure or gossyplure, were plced in ech cultivr plnting t ech loction throughout the seson. In 1975, popultions of cotton lefperfortors were smpled weekly by picking 30 leves from plnts from the center nd in ech of the four corners of ech plot t ech loction. Mines, free lrve, nd horseshoe stges of the insect were recorded. On Aug. 27 nd 29,1975, respectively, t the Mricop nd Hrquhl plots, MCPA (0.028kg i/hl plus chlorflurenol (0.56 kg i/hl ws pplied by irplne to two strips (verge 1 h/field) in ech cultivr. In 1976, lte seson cotton fruiting ws chemiclly terminted with Pennwlt TD'1l23 (3,4- dichloroisothizole 5-crboxylic cid) (1.1 kg i/hl plus chlormequt (CCC) [( 2-chloroethyl}trimethylmmonium chloride] (0.56 kg i/hl t Hrquhl, nd Pennwlt TD-1123 (1.1 kg i/hl plus chlorflurenol (0.56 kg i/hl t Mricop on Sept. 14 nd 15, respectively. Mterils were pplied with high clernce ground spryer to 8 rows of cotton on ech frm except one where 16 rows were treted. Ares treted rnged from 0.3 to 0.6 h. Cotton in four rows of ech cultivr ws picked t ech loction during the period from Oct. 27 to Dec.n, 1975, nd Oct. 6 to Dec. 22, Numbers of green bolls t first pick in ech cse were counted. In 1975, eight smples of soil from ech terminted nd untreted control plot were tken t the Hrquhl loctions, nd the pink bollwormdipuse lrve in the soil were counted. Results Lygus popultions were reltively low in both yers of the study (tble 17). Significntly fewer Lygus were found in nectriless cotton plots. In both yers, pek numbers of over 20 insects per 100 sweeps were reched in nectried cotton plots but not in nectriless cotton plots.