---- ----

2 8 2 5 11111 11 10 W I~ 22 ~ a m~ Jl

~ B~ 11

--~

- 1111118

11111125 1111114 1111116

MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDSmiddotJ963middotA

2 8 2 5 11111 1111

III 10 I~ f~~ 22IE m~ Jl ~ ~~ L11 bull aII bull

-

11111125 1111114 1111116

MICROCOPY RESOLUTION TEST (HART NAIJONAl BUREAU OF STANDARDSmiddot1963middotA

-Z lo~middot

L b~ RCF)CNCEL L shyJt 4 7 7

DO NOT LOAN

Boll Weevil Populations

as Affected by

Removal of Shed Cotton Forms

ID ~

1) tOc ( Technical Bulletin No 1277

Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE

CONTENTS

IageProcedure ________________________________ _

Results _____ __ _____ ___ _ _ ______ __ _ _ __ __ _ _ __ 2

1958 Studies____________________________ 2 1959 Studies___________________________ 8

Oonclusions _______________________________ 9

II ~ Growth ThrOlllh A~ltul Pro

Washington DC Issued November lH62

For ale by Ihe SuperintendeDt of Documents US Government Prinling Office Wahington 25 DC bull [ricc 10 cenlo

bull bull

Boll Weevil Populations as Affected by Removal of Shed Cotton Forms

By R E EYE and A R HOPKINS EntomoloJY Research Division AUricultumZ [iC8careh Serviee

One of the earliest methods investigated for control of th( boll weevil (AntlOnmnu8 grarulis Boh) which proved imprac6cal was hand collection and removal fWIll the soil surface of fruiting 10rms (squares or flower buds and bolls) containing eggs or laryae of this insect shed frol11 the cotton plllnt This method as laborious and time-consuming and mallY weeyih emerged frol11 th( forms before removal vas complete Also it was difficult especially for inexperishyenced laborers to find shed forms in grassy fields

The recent development of vacuum devices for collecting legume seed from the soil surface suggested the possibility that it similar device for collecting shed cotton forms might prove to be a practical meilns of boll weeil control Such a method should be most effecshytiye when shed squares containing eggs hid by oyenvinterecl females are on the soil surface for at this time cotton plants tHO small and usual1y there are few weeds in the field

To Cletermine the feasibility of such a method of control a prdinlishynary study was conClllcted at Florence SC during 1958 and 1050 to find out hat percentage of the total nmnber of shed formfi on the soil surface would haY(~ to be remOyeCLallc1 at what intelTals Differshyent removal rates and an insecticidal treatment of shed forms 011 the ~oil slllfacc wcre included in the study

PROCEDURE In both yeUlfi lB field cages arranged in randomized blocks each

covering one two-hundredths acre ere used Two rows of cotton each with 100 plant~ werc glOn in each cage-an eqlliVtllent of 40000 plants pel acre

In 1958 one pail of overwintered w(pib was placed ill eadl cage on iUay 22 and another pail on TUllO 12 FillPd fornls were IllllOed from thc soil surface in the CU at weekly intervals Hllli1 Xo(mbCl 2 at rates of 100 3D 20 Imcl ]0 p(gtLClnt tltprc being thlpe eages (replicatP) for etelL 1Pllloval mte In six cages no shed fOlIl1S wpre remoreclj in three of these cages heptnchlor grtnllles were applIed to the soil suril(C at the rate or 1 POlllHl of toxicnnt per tt(L(gt 011 111110 W and again on July 10

The weevils introdncecl into fOllr of Ow (ag(s ltlie[ not SlHTin In these cages populations wcre reestablished by adding the following

1 Now with the Canadian Department of Forestry

641)727-62 1

1

number of squares containing eggs [ in a cage with a 30-percent removal rate 8 in a cage with a 20-percent removal rate 10 each in two cages where no forms were removed (one replicate with heptashychlor granules and one untreated replicate)

All squtlres 1 week or older on 20 to 50 plants selecteel at random in each cage were examined each week during the entire eason for feeding anel egg punctures und the presence Of adult eedls The number of squares and the kinds of punctures were then calculated on an acre basis An fOllmi shed and remoed from the soil surface were also examined for egg and feeding punctures Shed not attribshyuted to weevils was recorded as being for other causes which inshycluded damage from bollworms Heliothis spp noted in a few cages

In 1)5) one pair of ovenyintered veeils was placed in ench cage on Mny 2G and another pail on Tune 17 Shed forms were removed front the cages eyery 5 days until November 2 at rates of 100 DO 80 70 and 50 pelcent three replicates being proyic1cd ror each rel110ntl rate X 0 shed forms were removed from three cages

Examinations of forl11s both s11ec1 and on the plants were tIl( same as those made in 1058 except that nIl forms on 30 plants ill each cage wero examiJlec1~ and apparent causeS of shed were determined only until August 20 In 1050 the number of removed shed forms from which boll weevils had emerged US recorded

Yields were obtained by picking all of the cotton in each cage and cOllYerting th( amonnts to an acre basis

RESULTS

1958 Studies Figmes 1a ancl 11gt representing dabt ftOI1l cages where no shrc1

forms were removed inelicate the typical itllntion in the Constnl Plaill of South Carolina As Fyr et a7 notecl most of tl1e cotton is set in a period before the emerging first-generation e(vi15 can eause ferious (lamape and subsequent poplllation buildups yirtually preent -further settil1g of squares As the populations rie and no squares arc antilable migration enSlles with the alleviation or population presshySure This in conjunction with th( conCl1llenj mntUlntion of th( holli permits the plants to resum( oqllaring The inability of middothe w(eil to maintain high populations with resultant high infestatiol1 levels during tIle periocl of low square procluetion is alo (iltlent Thigt failure occurs because the weevils clestroymost of the squares before tll(Y arc large enollgh to 1(c(iv( egg clq)oition

Only two or t1l( Illree replicates in the proup frolll whilh no 81lPd forllls were rellloyed (lip la) had quare ]gtIoltln([ iOll of COlI-eqUlnc( after AlIgnst H In the third l(plieale the w(gt(gtyils had diminated ltlmost all squares and the in flstat ion at that t inH was (olliic1(recl to be zero Th(lefol( the infestations show11 whieh ale the lCrng( of three repl icates II1tIst be consiclend con(rntt i(

Figure 1b repr(~ellting the treale(l cag(s frol1l whi(h 110 ih(d forIlls were remoecl indicat(s that the heplnchlol granlllps hil((1 [0 control tll( emerging w((middotils although a slight suppression as indicflled

Fye R E Hopkins A It and Walkel RI Fiehl Experiments on Conshytrol or Overwintered BoLL Yecmiddotili rOH Econ Ent 4(4) 622-62middot1 lJ61

Ie

2

-

00 a NO REMOVAL I d NO REMOVAl240 198 199

eo200 -- SQUARES PER

ACRE 1amp0 00

120 4O~

gten 80

~ w~Cl 40 ) III

~pound 0 ~

t ~m 240

m 00

~

~ 200 0laquo ~

II 160 w~ 11

120 ~ III

40 II lt( eo II ) lt(

W)a III 40 a

III Z 0 ~o~

5 240 ~ U

oo~200 z 0 ~ ~ 160 w~

120 40

eo

40

k w

AUG JUlY AUG SEPT OCTMY

FIGURE I-Cotton squares per acre and boll weevil infestation under 00- and 100-percent removal of shed forms and with no reshy111 movlll lllorell(e SC 1)58-50

The cotton squared well throughout August possibly because of this slight suppression and this continued squaring provided the necesshysary medium for a high reproductive rate

Figures 2a 2b and 2c representing (lttta from (ages where 10 20 and 30 percent of rhe shed forms were removed are remarkably simishylar 10 figUlcS In and 10 except for the higher infestation pnrcentages

Hemoval of 10 20 and 30 percent of I1lC shed forms was ineffective in prexenting development of boll weevil populations sufliciently large to cause economic damage In fact there as substantial (vidence that removal of these 10IY percentages might have increased the popushylation potential Apparently this increase was attained bv a subtle relaxation of weeyil population pressure to a degree j-hat ellabled the cotton plant to maintain a constnnt supply of squares of suilicient size for oviposition by the weeyil Thus higher population len~ls yere sustamed

The immensity of the losses from shed for111s caused bv the boll eeyil is shown in tnhle 1 Vhen 10 20 and 30 percent 0pound the shed for111s were removed at -weekly intervals 90 80 and 70 percent of the originnl groups still remained on the next removal date before deterishyorating beyonel recognition resulting in another 0 16 and 21 percent being remo-ved respectively Thus remoal of 10 20 anel 30 percent of shed forms actually represented tlle removal of 10 3G and 51 pershycent of the total The total number of fOlms shed pel acre by Aushygust 29 a date niter which a c1eyeloping sqllare did not haye time to mature to a productive boll indicates that a loss through shedding of about six to eight for111s per p1ant occllrred dnril1Q the productivefruiting period -

The percentage of forms shed for difrerent reasons thlOlgh Aushygust 29 is also shown in table 1 Only 18 to 131 percent of the squares shed through August 29 were shed for other canses compared with 3middot10 to 101 percent of the bolls c1llling the same period

The number of shed forms containing eggs after August W ~hoed considerable potential for the production of a large 1llllllher of weeyi1s that could overwinter The potential was greater than thaI indicated by shed forms since eeyi1s thnt can overwinter a1-o cleelop in bolls that fail to shee1

The ineffectiveness of the removal of smaJI pCL(elltagegt- of lthed for111s is shown in the average infestations from Tune 12 throngh August 21 and N ovemher 3 and in yields of seed eotton pel acre (table 2) HOWCC1 differences werc 110t significnllt in infestntion or yield between remoYtl1 1ec1s Since weei1s were reinfroduced in rep1 icates of severtll treatments in which oligina 1 introcluef ions flilec1 to establish populations there was consclcrflble lliation in infestashytion between replicates within treatments~ resulting in no signiHcant difference even though the infestation at the lOO-peLcent remontlleyel was consid~lflbly lower than in all other treatments Yi(llds were affected 101 fhe same reason flncl yield datn are 11on with and withshyout these replicates Yields in rep1icateR here the initia1 poplation stlrvi vecl er( much lower than in those where 1fltcL introdllctions were necessary Then introductions were made hter a hewy set of bolls occurred before population pressures of the boll weevil cleveloped

bull

4

CONTENTS

IageProcedure ________________________________ _

Results _____ __ _____ ___ _ _ ______ __ _ _ __ __ _ _ __ 2

1958 Studies____________________________ 2 1959 Studies___________________________ 8

Oonclusions _______________________________ 9

II ~ Growth ThrOlllh A~ltul Pro

Washington DC Issued November lH62

For ale by Ihe SuperintendeDt of Documents US Government Prinling Office Wahington 25 DC bull [ricc 10 cenlo

bull bull

Boll Weevil Populations as Affected by Removal of Shed Cotton Forms

By R E EYE and A R HOPKINS EntomoloJY Research Division AUricultumZ [iC8careh Serviee

One of the earliest methods investigated for control of th( boll weevil (AntlOnmnu8 grarulis Boh) which proved imprac6cal was hand collection and removal fWIll the soil surface of fruiting 10rms (squares or flower buds and bolls) containing eggs or laryae of this insect shed frol11 the cotton plllnt This method as laborious and time-consuming and mallY weeyih emerged frol11 th( forms before removal vas complete Also it was difficult especially for inexperishyenced laborers to find shed forms in grassy fields

The recent development of vacuum devices for collecting legume seed from the soil surface suggested the possibility that it similar device for collecting shed cotton forms might prove to be a practical meilns of boll weeil control Such a method should be most effecshytiye when shed squares containing eggs hid by oyenvinterecl females are on the soil surface for at this time cotton plants tHO small and usual1y there are few weeds in the field

To Cletermine the feasibility of such a method of control a prdinlishynary study was conClllcted at Florence SC during 1958 and 1050 to find out hat percentage of the total nmnber of shed formfi on the soil surface would haY(~ to be remOyeCLallc1 at what intelTals Differshyent removal rates and an insecticidal treatment of shed forms 011 the ~oil slllfacc wcre included in the study

PROCEDURE In both yeUlfi lB field cages arranged in randomized blocks each

covering one two-hundredths acre ere used Two rows of cotton each with 100 plant~ werc glOn in each cage-an eqlliVtllent of 40000 plants pel acre

In 1958 one pail of overwintered w(pib was placed ill eadl cage on iUay 22 and another pail on TUllO 12 FillPd fornls were IllllOed from thc soil surface in the CU at weekly intervals Hllli1 Xo(mbCl 2 at rates of 100 3D 20 Imcl ]0 p(gtLClnt tltprc being thlpe eages (replicatP) for etelL 1Pllloval mte In six cages no shed fOlIl1S wpre remoreclj in three of these cages heptnchlor grtnllles were applIed to the soil suril(C at the rate or 1 POlllHl of toxicnnt per tt(L(gt 011 111110 W and again on July 10

The weevils introdncecl into fOllr of Ow (ag(s ltlie[ not SlHTin In these cages populations wcre reestablished by adding the following

1 Now with the Canadian Department of Forestry

641)727-62 1

1

number of squares containing eggs [ in a cage with a 30-percent removal rate 8 in a cage with a 20-percent removal rate 10 each in two cages where no forms were removed (one replicate with heptashychlor granules and one untreated replicate)

All squtlres 1 week or older on 20 to 50 plants selecteel at random in each cage were examined each week during the entire eason for feeding anel egg punctures und the presence Of adult eedls The number of squares and the kinds of punctures were then calculated on an acre basis An fOllmi shed and remoed from the soil surface were also examined for egg and feeding punctures Shed not attribshyuted to weevils was recorded as being for other causes which inshycluded damage from bollworms Heliothis spp noted in a few cages

In 1)5) one pair of ovenyintered veeils was placed in ench cage on Mny 2G and another pail on Tune 17 Shed forms were removed front the cages eyery 5 days until November 2 at rates of 100 DO 80 70 and 50 pelcent three replicates being proyic1cd ror each rel110ntl rate X 0 shed forms were removed from three cages

Examinations of forl11s both s11ec1 and on the plants were tIl( same as those made in 1058 except that nIl forms on 30 plants ill each cage wero examiJlec1~ and apparent causeS of shed were determined only until August 20 In 1050 the number of removed shed forms from which boll weevils had emerged US recorded

Yields were obtained by picking all of the cotton in each cage and cOllYerting th( amonnts to an acre basis

RESULTS

1958 Studies Figmes 1a ancl 11gt representing dabt ftOI1l cages where no shrc1

forms were removed inelicate the typical itllntion in the Constnl Plaill of South Carolina As Fyr et a7 notecl most of tl1e cotton is set in a period before the emerging first-generation e(vi15 can eause ferious (lamape and subsequent poplllation buildups yirtually preent -further settil1g of squares As the populations rie and no squares arc antilable migration enSlles with the alleviation or population presshySure This in conjunction with th( conCl1llenj mntUlntion of th( holli permits the plants to resum( oqllaring The inability of middothe w(eil to maintain high populations with resultant high infestatiol1 levels during tIle periocl of low square procluetion is alo (iltlent Thigt failure occurs because the weevils clestroymost of the squares before tll(Y arc large enollgh to 1(c(iv( egg clq)oition

Only two or t1l( Illree replicates in the proup frolll whilh no 81lPd forllls were rellloyed (lip la) had quare ]gtIoltln([ iOll of COlI-eqUlnc( after AlIgnst H In the third l(plieale the w(gt(gtyils had diminated ltlmost all squares and the in flstat ion at that t inH was (olliic1(recl to be zero Th(lefol( the infestations show11 whieh ale the lCrng( of three repl icates II1tIst be consiclend con(rntt i(

Figure 1b repr(~ellting the treale(l cag(s frol1l whi(h 110 ih(d forIlls were remoecl indicat(s that the heplnchlol granlllps hil((1 [0 control tll( emerging w((middotils although a slight suppression as indicflled

Fye R E Hopkins A It and Walkel RI Fiehl Experiments on Conshytrol or Overwintered BoLL Yecmiddotili rOH Econ Ent 4(4) 622-62middot1 lJ61

Ie

2

-

00 a NO REMOVAL I d NO REMOVAl240 198 199

eo200 -- SQUARES PER

ACRE 1amp0 00

120 4O~

gten 80

~ w~Cl 40 ) III

~pound 0 ~

t ~m 240

m 00

~

~ 200 0laquo ~

II 160 w~ 11

120 ~ III

40 II lt( eo II ) lt(

W)a III 40 a

III Z 0 ~o~

5 240 ~ U

oo~200 z 0 ~ ~ 160 w~

120 40

eo

40

k w

AUG JUlY AUG SEPT OCTMY

FIGURE I-Cotton squares per acre and boll weevil infestation under 00- and 100-percent removal of shed forms and with no reshy111 movlll lllorell(e SC 1)58-50

The cotton squared well throughout August possibly because of this slight suppression and this continued squaring provided the necesshysary medium for a high reproductive rate

Figures 2a 2b and 2c representing (lttta from (ages where 10 20 and 30 percent of rhe shed forms were removed are remarkably simishylar 10 figUlcS In and 10 except for the higher infestation pnrcentages

Hemoval of 10 20 and 30 percent of I1lC shed forms was ineffective in prexenting development of boll weevil populations sufliciently large to cause economic damage In fact there as substantial (vidence that removal of these 10IY percentages might have increased the popushylation potential Apparently this increase was attained bv a subtle relaxation of weeyil population pressure to a degree j-hat ellabled the cotton plant to maintain a constnnt supply of squares of suilicient size for oviposition by the weeyil Thus higher population len~ls yere sustamed

The immensity of the losses from shed for111s caused bv the boll eeyil is shown in tnhle 1 Vhen 10 20 and 30 percent 0pound the shed for111s were removed at -weekly intervals 90 80 and 70 percent of the originnl groups still remained on the next removal date before deterishyorating beyonel recognition resulting in another 0 16 and 21 percent being remo-ved respectively Thus remoal of 10 20 anel 30 percent of shed forms actually represented tlle removal of 10 3G and 51 pershycent of the total The total number of fOlms shed pel acre by Aushygust 29 a date niter which a c1eyeloping sqllare did not haye time to mature to a productive boll indicates that a loss through shedding of about six to eight for111s per p1ant occllrred dnril1Q the productivefruiting period -

The percentage of forms shed for difrerent reasons thlOlgh Aushygust 29 is also shown in table 1 Only 18 to 131 percent of the squares shed through August 29 were shed for other canses compared with 3middot10 to 101 percent of the bolls c1llling the same period

The number of shed forms containing eggs after August W ~hoed considerable potential for the production of a large 1llllllher of weeyi1s that could overwinter The potential was greater than thaI indicated by shed forms since eeyi1s thnt can overwinter a1-o cleelop in bolls that fail to shee1

The ineffectiveness of the removal of smaJI pCL(elltagegt- of lthed for111s is shown in the average infestations from Tune 12 throngh August 21 and N ovemher 3 and in yields of seed eotton pel acre (table 2) HOWCC1 differences werc 110t significnllt in infestntion or yield between remoYtl1 1ec1s Since weei1s were reinfroduced in rep1 icates of severtll treatments in which oligina 1 introcluef ions flilec1 to establish populations there was consclcrflble lliation in infestashytion between replicates within treatments~ resulting in no signiHcant difference even though the infestation at the lOO-peLcent remontlleyel was consid~lflbly lower than in all other treatments Yi(llds were affected 101 fhe same reason flncl yield datn are 11on with and withshyout these replicates Yields in rep1icateR here the initia1 poplation stlrvi vecl er( much lower than in those where 1fltcL introdllctions were necessary Then introductions were made hter a hewy set of bolls occurred before population pressures of the boll weevil cleveloped

bull

4

bull bull

Boll Weevil Populations as Affected by Removal of Shed Cotton Forms

By R E EYE and A R HOPKINS EntomoloJY Research Division AUricultumZ [iC8careh Serviee

One of the earliest methods investigated for control of th( boll weevil (AntlOnmnu8 grarulis Boh) which proved imprac6cal was hand collection and removal fWIll the soil surface of fruiting 10rms (squares or flower buds and bolls) containing eggs or laryae of this insect shed frol11 the cotton plllnt This method as laborious and time-consuming and mallY weeyih emerged frol11 th( forms before removal vas complete Also it was difficult especially for inexperishyenced laborers to find shed forms in grassy fields

The recent development of vacuum devices for collecting legume seed from the soil surface suggested the possibility that it similar device for collecting shed cotton forms might prove to be a practical meilns of boll weeil control Such a method should be most effecshytiye when shed squares containing eggs hid by oyenvinterecl females are on the soil surface for at this time cotton plants tHO small and usual1y there are few weeds in the field

To Cletermine the feasibility of such a method of control a prdinlishynary study was conClllcted at Florence SC during 1958 and 1050 to find out hat percentage of the total nmnber of shed formfi on the soil surface would haY(~ to be remOyeCLallc1 at what intelTals Differshyent removal rates and an insecticidal treatment of shed forms 011 the ~oil slllfacc wcre included in the study

PROCEDURE In both yeUlfi lB field cages arranged in randomized blocks each

covering one two-hundredths acre ere used Two rows of cotton each with 100 plant~ werc glOn in each cage-an eqlliVtllent of 40000 plants pel acre

In 1958 one pail of overwintered w(pib was placed ill eadl cage on iUay 22 and another pail on TUllO 12 FillPd fornls were IllllOed from thc soil surface in the CU at weekly intervals Hllli1 Xo(mbCl 2 at rates of 100 3D 20 Imcl ]0 p(gtLClnt tltprc being thlpe eages (replicatP) for etelL 1Pllloval mte In six cages no shed fOlIl1S wpre remoreclj in three of these cages heptnchlor grtnllles were applIed to the soil suril(C at the rate or 1 POlllHl of toxicnnt per tt(L(gt 011 111110 W and again on July 10

The weevils introdncecl into fOllr of Ow (ag(s ltlie[ not SlHTin In these cages populations wcre reestablished by adding the following

1 Now with the Canadian Department of Forestry

641)727-62 1

1

number of squares containing eggs [ in a cage with a 30-percent removal rate 8 in a cage with a 20-percent removal rate 10 each in two cages where no forms were removed (one replicate with heptashychlor granules and one untreated replicate)

All squtlres 1 week or older on 20 to 50 plants selecteel at random in each cage were examined each week during the entire eason for feeding anel egg punctures und the presence Of adult eedls The number of squares and the kinds of punctures were then calculated on an acre basis An fOllmi shed and remoed from the soil surface were also examined for egg and feeding punctures Shed not attribshyuted to weevils was recorded as being for other causes which inshycluded damage from bollworms Heliothis spp noted in a few cages

In 1)5) one pair of ovenyintered veeils was placed in ench cage on Mny 2G and another pail on Tune 17 Shed forms were removed front the cages eyery 5 days until November 2 at rates of 100 DO 80 70 and 50 pelcent three replicates being proyic1cd ror each rel110ntl rate X 0 shed forms were removed from three cages

Examinations of forl11s both s11ec1 and on the plants were tIl( same as those made in 1058 except that nIl forms on 30 plants ill each cage wero examiJlec1~ and apparent causeS of shed were determined only until August 20 In 1050 the number of removed shed forms from which boll weevils had emerged US recorded

Yields were obtained by picking all of the cotton in each cage and cOllYerting th( amonnts to an acre basis

RESULTS

1958 Studies Figmes 1a ancl 11gt representing dabt ftOI1l cages where no shrc1

forms were removed inelicate the typical itllntion in the Constnl Plaill of South Carolina As Fyr et a7 notecl most of tl1e cotton is set in a period before the emerging first-generation e(vi15 can eause ferious (lamape and subsequent poplllation buildups yirtually preent -further settil1g of squares As the populations rie and no squares arc antilable migration enSlles with the alleviation or population presshySure This in conjunction with th( conCl1llenj mntUlntion of th( holli permits the plants to resum( oqllaring The inability of middothe w(eil to maintain high populations with resultant high infestatiol1 levels during tIle periocl of low square procluetion is alo (iltlent Thigt failure occurs because the weevils clestroymost of the squares before tll(Y arc large enollgh to 1(c(iv( egg clq)oition

Only two or t1l( Illree replicates in the proup frolll whilh no 81lPd forllls were rellloyed (lip la) had quare ]gtIoltln([ iOll of COlI-eqUlnc( after AlIgnst H In the third l(plieale the w(gt(gtyils had diminated ltlmost all squares and the in flstat ion at that t inH was (olliic1(recl to be zero Th(lefol( the infestations show11 whieh ale the lCrng( of three repl icates II1tIst be consiclend con(rntt i(

Figure 1b repr(~ellting the treale(l cag(s frol1l whi(h 110 ih(d forIlls were remoecl indicat(s that the heplnchlol granlllps hil((1 [0 control tll( emerging w((middotils although a slight suppression as indicflled

Fye R E Hopkins A It and Walkel RI Fiehl Experiments on Conshytrol or Overwintered BoLL Yecmiddotili rOH Econ Ent 4(4) 622-62middot1 lJ61

Ie

2

-

00 a NO REMOVAL I d NO REMOVAl240 198 199

eo200 -- SQUARES PER

ACRE 1amp0 00

120 4O~

gten 80

~ w~Cl 40 ) III

~pound 0 ~

t ~m 240

m 00

~

~ 200 0laquo ~

II 160 w~ 11

120 ~ III

40 II lt( eo II ) lt(

W)a III 40 a

III Z 0 ~o~

5 240 ~ U

oo~200 z 0 ~ ~ 160 w~

120 40

eo

40

k w

AUG JUlY AUG SEPT OCTMY

FIGURE I-Cotton squares per acre and boll weevil infestation under 00- and 100-percent removal of shed forms and with no reshy111 movlll lllorell(e SC 1)58-50

The cotton squared well throughout August possibly because of this slight suppression and this continued squaring provided the necesshysary medium for a high reproductive rate

Figures 2a 2b and 2c representing (lttta from (ages where 10 20 and 30 percent of rhe shed forms were removed are remarkably simishylar 10 figUlcS In and 10 except for the higher infestation pnrcentages

Hemoval of 10 20 and 30 percent of I1lC shed forms was ineffective in prexenting development of boll weevil populations sufliciently large to cause economic damage In fact there as substantial (vidence that removal of these 10IY percentages might have increased the popushylation potential Apparently this increase was attained bv a subtle relaxation of weeyil population pressure to a degree j-hat ellabled the cotton plant to maintain a constnnt supply of squares of suilicient size for oviposition by the weeyil Thus higher population len~ls yere sustamed

The immensity of the losses from shed for111s caused bv the boll eeyil is shown in tnhle 1 Vhen 10 20 and 30 percent 0pound the shed for111s were removed at -weekly intervals 90 80 and 70 percent of the originnl groups still remained on the next removal date before deterishyorating beyonel recognition resulting in another 0 16 and 21 percent being remo-ved respectively Thus remoal of 10 20 anel 30 percent of shed forms actually represented tlle removal of 10 3G and 51 pershycent of the total The total number of fOlms shed pel acre by Aushygust 29 a date niter which a c1eyeloping sqllare did not haye time to mature to a productive boll indicates that a loss through shedding of about six to eight for111s per p1ant occllrred dnril1Q the productivefruiting period -

The percentage of forms shed for difrerent reasons thlOlgh Aushygust 29 is also shown in table 1 Only 18 to 131 percent of the squares shed through August 29 were shed for other canses compared with 3middot10 to 101 percent of the bolls c1llling the same period

The number of shed forms containing eggs after August W ~hoed considerable potential for the production of a large 1llllllher of weeyi1s that could overwinter The potential was greater than thaI indicated by shed forms since eeyi1s thnt can overwinter a1-o cleelop in bolls that fail to shee1

The ineffectiveness of the removal of smaJI pCL(elltagegt- of lthed for111s is shown in the average infestations from Tune 12 throngh August 21 and N ovemher 3 and in yields of seed eotton pel acre (table 2) HOWCC1 differences werc 110t significnllt in infestntion or yield between remoYtl1 1ec1s Since weei1s were reinfroduced in rep1 icates of severtll treatments in which oligina 1 introcluef ions flilec1 to establish populations there was consclcrflble lliation in infestashytion between replicates within treatments~ resulting in no signiHcant difference even though the infestation at the lOO-peLcent remontlleyel was consid~lflbly lower than in all other treatments Yi(llds were affected 101 fhe same reason flncl yield datn are 11on with and withshyout these replicates Yields in rep1icateR here the initia1 poplation stlrvi vecl er( much lower than in those where 1fltcL introdllctions were necessary Then introductions were made hter a hewy set of bolls occurred before population pressures of the boll weevil cleveloped

bull

4

1

number of squares containing eggs [ in a cage with a 30-percent removal rate 8 in a cage with a 20-percent removal rate 10 each in two cages where no forms were removed (one replicate with heptashychlor granules and one untreated replicate)

All squtlres 1 week or older on 20 to 50 plants selecteel at random in each cage were examined each week during the entire eason for feeding anel egg punctures und the presence Of adult eedls The number of squares and the kinds of punctures were then calculated on an acre basis An fOllmi shed and remoed from the soil surface were also examined for egg and feeding punctures Shed not attribshyuted to weevils was recorded as being for other causes which inshycluded damage from bollworms Heliothis spp noted in a few cages

In 1)5) one pair of ovenyintered veeils was placed in ench cage on Mny 2G and another pail on Tune 17 Shed forms were removed front the cages eyery 5 days until November 2 at rates of 100 DO 80 70 and 50 pelcent three replicates being proyic1cd ror each rel110ntl rate X 0 shed forms were removed from three cages

Examinations of forl11s both s11ec1 and on the plants were tIl( same as those made in 1058 except that nIl forms on 30 plants ill each cage wero examiJlec1~ and apparent causeS of shed were determined only until August 20 In 1050 the number of removed shed forms from which boll weevils had emerged US recorded

Yields were obtained by picking all of the cotton in each cage and cOllYerting th( amonnts to an acre basis

RESULTS

1958 Studies Figmes 1a ancl 11gt representing dabt ftOI1l cages where no shrc1

forms were removed inelicate the typical itllntion in the Constnl Plaill of South Carolina As Fyr et a7 notecl most of tl1e cotton is set in a period before the emerging first-generation e(vi15 can eause ferious (lamape and subsequent poplllation buildups yirtually preent -further settil1g of squares As the populations rie and no squares arc antilable migration enSlles with the alleviation or population presshySure This in conjunction with th( conCl1llenj mntUlntion of th( holli permits the plants to resum( oqllaring The inability of middothe w(eil to maintain high populations with resultant high infestatiol1 levels during tIle periocl of low square procluetion is alo (iltlent Thigt failure occurs because the weevils clestroymost of the squares before tll(Y arc large enollgh to 1(c(iv( egg clq)oition

Only two or t1l( Illree replicates in the proup frolll whilh no 81lPd forllls were rellloyed (lip la) had quare ]gtIoltln([ iOll of COlI-eqUlnc( after AlIgnst H In the third l(plieale the w(gt(gtyils had diminated ltlmost all squares and the in flstat ion at that t inH was (olliic1(recl to be zero Th(lefol( the infestations show11 whieh ale the lCrng( of three repl icates II1tIst be consiclend con(rntt i(

Figure 1b repr(~ellting the treale(l cag(s frol1l whi(h 110 ih(d forIlls were remoecl indicat(s that the heplnchlol granlllps hil((1 [0 control tll( emerging w((middotils although a slight suppression as indicflled

Fye R E Hopkins A It and Walkel RI Fiehl Experiments on Conshytrol or Overwintered BoLL Yecmiddotili rOH Econ Ent 4(4) 622-62middot1 lJ61

Ie

2

-

00 a NO REMOVAL I d NO REMOVAl240 198 199

eo200 -- SQUARES PER

ACRE 1amp0 00

120 4O~

gten 80

~ w~Cl 40 ) III

~pound 0 ~

t ~m 240

m 00

~

~ 200 0laquo ~

II 160 w~ 11

120 ~ III

40 II lt( eo II ) lt(

W)a III 40 a

III Z 0 ~o~

5 240 ~ U

oo~200 z 0 ~ ~ 160 w~

120 40

eo

40

k w

AUG JUlY AUG SEPT OCTMY

FIGURE I-Cotton squares per acre and boll weevil infestation under 00- and 100-percent removal of shed forms and with no reshy111 movlll lllorell(e SC 1)58-50

The cotton squared well throughout August possibly because of this slight suppression and this continued squaring provided the necesshysary medium for a high reproductive rate

Figures 2a 2b and 2c representing (lttta from (ages where 10 20 and 30 percent of rhe shed forms were removed are remarkably simishylar 10 figUlcS In and 10 except for the higher infestation pnrcentages

Hemoval of 10 20 and 30 percent of I1lC shed forms was ineffective in prexenting development of boll weevil populations sufliciently large to cause economic damage In fact there as substantial (vidence that removal of these 10IY percentages might have increased the popushylation potential Apparently this increase was attained bv a subtle relaxation of weeyil population pressure to a degree j-hat ellabled the cotton plant to maintain a constnnt supply of squares of suilicient size for oviposition by the weeyil Thus higher population len~ls yere sustamed

The immensity of the losses from shed for111s caused bv the boll eeyil is shown in tnhle 1 Vhen 10 20 and 30 percent 0pound the shed for111s were removed at -weekly intervals 90 80 and 70 percent of the originnl groups still remained on the next removal date before deterishyorating beyonel recognition resulting in another 0 16 and 21 percent being remo-ved respectively Thus remoal of 10 20 anel 30 percent of shed forms actually represented tlle removal of 10 3G and 51 pershycent of the total The total number of fOlms shed pel acre by Aushygust 29 a date niter which a c1eyeloping sqllare did not haye time to mature to a productive boll indicates that a loss through shedding of about six to eight for111s per p1ant occllrred dnril1Q the productivefruiting period -

The percentage of forms shed for difrerent reasons thlOlgh Aushygust 29 is also shown in table 1 Only 18 to 131 percent of the squares shed through August 29 were shed for other canses compared with 3middot10 to 101 percent of the bolls c1llling the same period

The number of shed forms containing eggs after August W ~hoed considerable potential for the production of a large 1llllllher of weeyi1s that could overwinter The potential was greater than thaI indicated by shed forms since eeyi1s thnt can overwinter a1-o cleelop in bolls that fail to shee1

The ineffectiveness of the removal of smaJI pCL(elltagegt- of lthed for111s is shown in the average infestations from Tune 12 throngh August 21 and N ovemher 3 and in yields of seed eotton pel acre (table 2) HOWCC1 differences werc 110t significnllt in infestntion or yield between remoYtl1 1ec1s Since weei1s were reinfroduced in rep1 icates of severtll treatments in which oligina 1 introcluef ions flilec1 to establish populations there was consclcrflble lliation in infestashytion between replicates within treatments~ resulting in no signiHcant difference even though the infestation at the lOO-peLcent remontlleyel was consid~lflbly lower than in all other treatments Yi(llds were affected 101 fhe same reason flncl yield datn are 11on with and withshyout these replicates Yields in rep1icateR here the initia1 poplation stlrvi vecl er( much lower than in those where 1fltcL introdllctions were necessary Then introductions were made hter a hewy set of bolls occurred before population pressures of the boll weevil cleveloped

bull

4

-

00 a NO REMOVAL I d NO REMOVAl240 198 199

eo200 -- SQUARES PER

ACRE 1amp0 00

120 4O~

gten 80

~ w~Cl 40 ) III

~pound 0 ~

t ~m 240

m 00

~

~ 200 0laquo ~

II 160 w~ 11

120 ~ III

40 II lt( eo II ) lt(

W)a III 40 a

III Z 0 ~o~

5 240 ~ U

oo~200 z 0 ~ ~ 160 w~

120 40

eo

40

k w

AUG JUlY AUG SEPT OCTMY

FIGURE I-Cotton squares per acre and boll weevil infestation under 00- and 100-percent removal of shed forms and with no reshy111 movlll lllorell(e SC 1)58-50

The cotton squared well throughout August possibly because of this slight suppression and this continued squaring provided the necesshysary medium for a high reproductive rate

Figures 2a 2b and 2c representing (lttta from (ages where 10 20 and 30 percent of rhe shed forms were removed are remarkably simishylar 10 figUlcS In and 10 except for the higher infestation pnrcentages

Hemoval of 10 20 and 30 percent of I1lC shed forms was ineffective in prexenting development of boll weevil populations sufliciently large to cause economic damage In fact there as substantial (vidence that removal of these 10IY percentages might have increased the popushylation potential Apparently this increase was attained bv a subtle relaxation of weeyil population pressure to a degree j-hat ellabled the cotton plant to maintain a constnnt supply of squares of suilicient size for oviposition by the weeyil Thus higher population len~ls yere sustamed

The immensity of the losses from shed for111s caused bv the boll eeyil is shown in tnhle 1 Vhen 10 20 and 30 percent 0pound the shed for111s were removed at -weekly intervals 90 80 and 70 percent of the originnl groups still remained on the next removal date before deterishyorating beyonel recognition resulting in another 0 16 and 21 percent being remo-ved respectively Thus remoal of 10 20 anel 30 percent of shed forms actually represented tlle removal of 10 3G and 51 pershycent of the total The total number of fOlms shed pel acre by Aushygust 29 a date niter which a c1eyeloping sqllare did not haye time to mature to a productive boll indicates that a loss through shedding of about six to eight for111s per p1ant occllrred dnril1Q the productivefruiting period -

The percentage of forms shed for difrerent reasons thlOlgh Aushygust 29 is also shown in table 1 Only 18 to 131 percent of the squares shed through August 29 were shed for other canses compared with 3middot10 to 101 percent of the bolls c1llling the same period

The number of shed forms containing eggs after August W ~hoed considerable potential for the production of a large 1llllllher of weeyi1s that could overwinter The potential was greater than thaI indicated by shed forms since eeyi1s thnt can overwinter a1-o cleelop in bolls that fail to shee1

The ineffectiveness of the removal of smaJI pCL(elltagegt- of lthed for111s is shown in the average infestations from Tune 12 throngh August 21 and N ovemher 3 and in yields of seed eotton pel acre (table 2) HOWCC1 differences werc 110t significnllt in infestntion or yield between remoYtl1 1ec1s Since weei1s were reinfroduced in rep1 icates of severtll treatments in which oligina 1 introcluef ions flilec1 to establish populations there was consclcrflble lliation in infestashytion between replicates within treatments~ resulting in no signiHcant difference even though the infestation at the lOO-peLcent remontlleyel was consid~lflbly lower than in all other treatments Yi(llds were affected 101 fhe same reason flncl yield datn are 11on with and withshyout these replicates Yields in rep1icateR here the initia1 poplation stlrvi vecl er( much lower than in those where 1fltcL introdllctions were necessary Then introductions were made hter a hewy set of bolls occurred before population pressures of the boll weevil cleveloped

bull

4

The cotton squared well throughout August possibly because of this slight suppression and this continued squaring provided the necesshysary medium for a high reproductive rate

Figures 2a 2b and 2c representing (lttta from (ages where 10 20 and 30 percent of rhe shed forms were removed are remarkably simishylar 10 figUlcS In and 10 except for the higher infestation pnrcentages

Hemoval of 10 20 and 30 percent of I1lC shed forms was ineffective in prexenting development of boll weevil populations sufliciently large to cause economic damage In fact there as substantial (vidence that removal of these 10IY percentages might have increased the popushylation potential Apparently this increase was attained bv a subtle relaxation of weeyil population pressure to a degree j-hat ellabled the cotton plant to maintain a constnnt supply of squares of suilicient size for oviposition by the weeyil Thus higher population len~ls yere sustamed

The immensity of the losses from shed for111s caused bv the boll eeyil is shown in tnhle 1 Vhen 10 20 and 30 percent 0pound the shed for111s were removed at -weekly intervals 90 80 and 70 percent of the originnl groups still remained on the next removal date before deterishyorating beyonel recognition resulting in another 0 16 and 21 percent being remo-ved respectively Thus remoal of 10 20 anel 30 percent of shed forms actually represented tlle removal of 10 3G and 51 pershycent of the total The total number of fOlms shed pel acre by Aushygust 29 a date niter which a c1eyeloping sqllare did not haye time to mature to a productive boll indicates that a loss through shedding of about six to eight for111s per p1ant occllrred dnril1Q the productivefruiting period -

The percentage of forms shed for difrerent reasons thlOlgh Aushygust 29 is also shown in table 1 Only 18 to 131 percent of the squares shed through August 29 were shed for other canses compared with 3middot10 to 101 percent of the bolls c1llling the same period

The number of shed forms containing eggs after August W ~hoed considerable potential for the production of a large 1llllllher of weeyi1s that could overwinter The potential was greater than thaI indicated by shed forms since eeyi1s thnt can overwinter a1-o cleelop in bolls that fail to shee1

The ineffectiveness of the removal of smaJI pCL(elltagegt- of lthed for111s is shown in the average infestations from Tune 12 throngh August 21 and N ovemher 3 and in yields of seed eotton pel acre (table 2) HOWCC1 differences werc 110t significnllt in infestntion or yield between remoYtl1 1ec1s Since weei1s were reinfroduced in rep1 icates of severtll treatments in which oligina 1 introcluef ions flilec1 to establish populations there was consclcrflble lliation in infestashytion between replicates within treatments~ resulting in no signiHcant difference even though the infestation at the lOO-peLcent remontlleyel was consid~lflbly lower than in all other treatments Yi(llds were affected 101 fhe same reason flncl yield datn are 11on with and withshyout these replicates Yields in rep1icateR here the initia1 poplation stlrvi vecl er( much lower than in those where 1fltcL introdllctions were necessary Then introductions were made hter a hewy set of bolls occurred before population pressures of the boll weevil cleveloped

bull

4

~ - j

240 a 10-4 REMOVAL d lO REMOVAL kloo 1958 1959

200 ~INFESTATICN eo --SQUARES PER

160 ACRE 60

120

4( Ul

in 80 J

C 1amp1gt

Z laquo 40 20 1amp1

~ J 0

JI 100 0 240

J

II W

gt~ 200 CD80 laquo

~r 160

60 Ul 0 1amp1

~(I ~ 40 a 80

J laquo II 0 C(

20

540

z Ul 0 toshy

100 ~ ~ 240 U

~ 200 80 ~ Z

g 60 ~ 60 t120

40 80

20

tJG SEPT OCT

IiIGUllE 2-Cotton squares per acre and boll weevil infestation uodel 1020 30 50 70 and 80 pelcent removal of shed forms ~ Florenlte SO 1958-59

---

ltI)

lABTJ l-N~tmbe7s of f1ltiting forlns she(Z by colton pZants and (J(liUses of shed ---- _ _---__- ~--~ -------shy -

Removal rates (percentages) in

Numbers of forms hcd and removlCl 1050)11058 1llnd cnuses of shed

8ea 00 100100 50 7010 20 I 30 I 283 130 ________

SqullrtS shed pel crc ______________ J 81l 470 147 500 117 060 ---------- 388 670 288460 360 000 237 600 2)1500 262 500 345 600 280300 367 600

Squares rcmovCd pel acro __ - -------- 36000 53 100 75000 Pcrlentage of lqUtlrCs shed owing to

Boll weevil fceding punctures _--shy 21 8 16 (j 100 7 7 226 Hi 4 O 0 107 06 720 751 i O 8 765 76 7 Boll weevil egg punctures________ 72 6 70 5 7ltl 4 005

8 5 O 2 128 13 7 Other causeS _______ ------------ 5 6 30 5 7 18 5 4

211620Bolls shed per ncre _bull ____________ 117370 J20 000 130 middot10 --------- 150 030 108 570 164 060 -------shy180700 ]57 500 200500 262 700 Bolls removed per ncre______________ 22 300 13200 71 100 103 700 113200

Percentage of boll shed owing to 100 11 022 6 13 1 11 5 O 0Hall cevil fpoding pundurlil _-- 1(i 6 125 ]57 Boll weevil egg punctmes________ 25 middot1 20 ] 33 3 middotj25 16 8 20 8 O 5 160 177 Other causes___________________ 1gt80 67 j 51 a 34 0 701 67 - I 8 6 74 a 704

shy---~--~- ---- -- ~-----

I Forll1s remo([l through Allgust 20in 1958 lInd Augu1 2i in 1050 2 Xumbcr-1 of hd -1qunrls and bolls computllt] 01 bnsis of 1) 3(j- llnd 51-percent rcmovnl in 10- 20- ItlHl aO-pprcent treatment in

H15S and 75 )1 )6 lind )l percent in the 50- 70- SOmiddot Ilnd OOmiddotperecnl tl(lltnwnts in 1)50

--

~~-~ + --r~ ~f ~ ai( SjAamp r--

TJHL1~ 2--A1(I([I( p(J(enlaq( of boll 11cevil infestation and cotton yield in ca[les in whieh shed f01ms We1e

1(IIW1ed at different 7)C)cenla[le mtcs 1958-59 ~ _ ~__bull-______ ~ __ bullbull ~ _____-__ bull ___~u___ ___- ______________ --------

Yields (pound of seed cotton per ncre)Ayertge inrestation of sqllar(s

----1058 ----I In50 H)58 1959PerePIlL

]emodeglci

TUI12- II TOnne] =-j-r-U1-1-e--2----signifi- IJUlle 12- Signifi- 3 repli- 2 repli- 3 repli- Signifi-Au-( 21 ltW 3 Aug 21 Cllllce 5 Nov 3 CllIlCC 5 cates cntes u cntes cnnee 5

percent percent percent

o UmrtntecL 1 ~~ 2 ~--~ - -- ~-I-t-l----I 700L 1 980 ] G70 5lt18 b d oTnItcL---- 3(i ~ ~8middotl ____________________1__________ ---------- I J80 1070 ---------- --------- shy

~g=========1 ~ ~ ~t ~ j======i==~===~I==== ========== I ~~g ------620- ========== ====== 30___________ -1 367 UO (j 1--------------------1---------- ---------- 1820 130 ---------- --------- shy50 ____________ 11 ___ ______1__________ 17 i n GO 8 n __________ __________ G48 b d 70_______________________________ 1 middot128 n b I 6G2t b __________ ---------- J238 b e RO--- bull -o-l---------- ----- ---1 middot122 It b 660 a h __________ __________ 1180 b cDO ____________ ___ -_ _ _______ _j aD 1 b G2 0 b __________ __________ 1 noo it

100___ bull ______ 270 250 3G0 b I 013 b 2180 ---------- 2115 a bull __ bullbullbullbull __ 0_ __ bull I 0 1 ______ _0__- bullbullbulll______________________ ____-____1

bull olrlll~ fo1oed by thl SIIlW ll [N art not iJJlifi(an (Iy difflltnt middotr(Ill~ followed by different letter are significantly different gt n(plicl(~ in hilth ()ri~dnill inlro(IlNI bo1 wleil~ tlldved

_1

I

In two of the replicates where all shed forms were removed no egO punctures were found tfter August 21 and no adults after J u1y 31 Thus the infestation levels shown in figme lc after these dates are somewhat misleading representing the mfestation in only one replicate but averaged for the three The yields in the two replicates in which weeyils were controlled were 2860 and 3600 pounds of seed cotton pel acre In the Ihirc1 rep 1 icnte where the infestation was not brought under control until the end of September the yield was only 1000 pounds per acre resulting in no significant difierence between this and other treatm(nts The yield in the same replicate was also reduced by 11011worms Although c1Uferences in infestation and yield were not significant the data mdicates that reshymoval of aU shed forms at weekly intervals provided considerable control of the bon weevil uncleI conditions of this study

1959 Studies Since the studies in 1058 showed that weekly remoY[11 of 30 percent

of the shed squares did not reduce weevil populations and 100 percent removal resulted ill considerable reduction the studies in 1059 were directed at determining the lowest removal leel at 5-c1ay intervals between these extremes that Qule1 afford economic control

Removal of 50 percent of the shee1 forms was not effective in conshytrolling the boll weevil (fig 2d) Since each forl11 was present at the time of two removals at 5-day intervals before deteriorating beyond recognition the actual removal was 75 percent However removal of forms yith egg punctures actnally remained neal 50 percent since many of the weevils emerged from squares remaining in the cages beshyfore the subsequent removal (table 3) A total of 104700 forms (sqnares and bolls) per acre were mmoved by August 2G and 53D600 forms per acre were sheel During this period the equivalent of 10851 weevilf per acre emerged The effects of the early emergence of large numbers of weevils and the subsequent high infestation levels during tIle main fruiting period of the plant were mflected in the average percentages of infestation through August 21 and N ovembcr 3 and in the vield (tf1ble 2) The infestation was significantly higher than for the 90- andlOO-percent removnl levels and the yield was significantly lower These data show theinefiectiveness of a GO-percent remoyal of shed forms every 5 clays

TAIIIg ~-Total pelcentaqes oj shed f01YM jr01n which boll Weevils hacl eme1ged into the cages prior to removal of jOlrns eVeN 5 days June 19-Auguit 201959

Percentage of emergence from Percentage of forms removed

BCJuares Bolls

50_______________________________________ _ 25 3170 ________________________________________1 bull5 7 4080 ________________________________________ 1 31 37

38 ~3 I23 13~g6~=~====================================1 -----~- ----

8

SevcuLy- and ei[[hty-pclcent rcmoals (actnally D1- and DO-percent because of form presence at two re1110[1Is) showed a marked similaeshyity and were more Cffectic than the 50-percent relllomllewl (figs2e and 2f) The total number of for111S (sqllfuCs and bolls) l-ernoyec1 through August 26 (table 1) represents a shed of 187030 foems per acre in cages with the IO-percent relllovnJ rate and 524060 for the 80-percent removal rute Although this shed vas less than in the cages with 100-percent removal (30300) an carliee Ellleegence of large populations and accompanying infestation levels in early JUly occurred This is the critiml portion of the fruiting period (Fye at al)2 The ayemge infestation and yield data cleL11y indicate the middle position beteCn the fJO- ancllOO-pelcent remontlleTels The slightly 10wCl yield for the SO-percent removal ratE compnred with the 10-percent rate cnn probnbly be necounted for by 10lt(gt enused by the bollworm

Dal1 from cngCs from which DO (nclnally Dn percent bCcllnse of form presence nt two lemoyals) and 100 percCllt of the fallen forms ere removed show cOl1siclemble similltrity (figs Ie nnd 1pound) The lD1150 forms (squarCs and bolls) shed per ntlC in tIl(gt (lO-pclcentshylemontl-rnte cages does not ltpPlonch thC U30300 removed at the rnte of 100 percent but it is suspected that the subtle relnxnt iOll of weejJ prCsnrc on tiny forming squares in Ihe IOO-pCrcent-lCmoal-ratr cages and ideal growing conditions for the cotton may ncconnt for this difference nnd the differences in the numbers of squares produced with the 50- 70- and SO-percent removal rates

Consic1erntion of the nvernge infCstations nncl the Yield (tlthle 2) in the 90- and IOO-percCnt-rCmonJl series teCals little difference in the two lCnls The (lxtencled pCrioc1 of suppressed ee~il populiltions during the Cariy Tmitillg period (figs 1e and If) w11ieh mnnifests itself as the lowered infestation percentage further supports an earl ier contention (Fye et a7r thnt endy boll sci with subseqnent boll proshytect ion should be nn nc1equate control program Tor tll( boll middoteeil

CONCLUSIONS Thus from this data it mny be concluded thnt ally squarC remoal

in the field HUlst be at the rnte of 00 to 100 percent removal must be nccomplished nt 5- or fewer-clay internLls and must be mOilt eflicient in the enr1y and mid fraiting pCriod if control of the boll wPCil is to be nttaincc1

See footnote 2 p 2

9

---

ltI)

lABTJ l-N~tmbe7s of f1ltiting forlns she(Z by colton pZants and (J(liUses of shed ---- _ _---__- ~--~ -------shy -

Removal rates (percentages) in

Numbers of forms hcd and removlCl 1050)11058 1llnd cnuses of shed

8ea 00 100100 50 7010 20 I 30 I 283 130 ________

SqullrtS shed pel crc ______________ J 81l 470 147 500 117 060 ---------- 388 670 288460 360 000 237 600 2)1500 262 500 345 600 280300 367 600

Squares rcmovCd pel acro __ - -------- 36000 53 100 75000 Pcrlentage of lqUtlrCs shed owing to

Boll weevil fceding punctures _--shy 21 8 16 (j 100 7 7 226 Hi 4 O 0 107 06 720 751 i O 8 765 76 7 Boll weevil egg punctures________ 72 6 70 5 7ltl 4 005

8 5 O 2 128 13 7 Other causeS _______ ------------ 5 6 30 5 7 18 5 4

211620Bolls shed per ncre _bull ____________ 117370 J20 000 130 middot10 --------- 150 030 108 570 164 060 -------shy180700 ]57 500 200500 262 700 Bolls removed per ncre______________ 22 300 13200 71 100 103 700 113200

Percentage of boll shed owing to 100 11 022 6 13 1 11 5 O 0Hall cevil fpoding pundurlil _-- 1(i 6 125 ]57 Boll weevil egg punctmes________ 25 middot1 20 ] 33 3 middotj25 16 8 20 8 O 5 160 177 Other causes___________________ 1gt80 67 j 51 a 34 0 701 67 - I 8 6 74 a 704

shy---~--~- ---- -- ~-----

I Forll1s remo([l through Allgust 20in 1958 lInd Augu1 2i in 1050 2 Xumbcr-1 of hd -1qunrls and bolls computllt] 01 bnsis of 1) 3(j- llnd 51-percent rcmovnl in 10- 20- ItlHl aO-pprcent treatment in

H15S and 75 )1 )6 lind )l percent in the 50- 70- SOmiddot Ilnd OOmiddotperecnl tl(lltnwnts in 1)50

--

~~-~ + --r~ ~f ~ ai( SjAamp r--

TJHL1~ 2--A1(I([I( p(J(enlaq( of boll 11cevil infestation and cotton yield in ca[les in whieh shed f01ms We1e

1(IIW1ed at different 7)C)cenla[le mtcs 1958-59 ~ _ ~__bull-______ ~ __ bullbull ~ _____-__ bull ___~u___ ___- ______________ --------

Yields (pound of seed cotton per ncre)Ayertge inrestation of sqllar(s

----1058 ----I In50 H)58 1959PerePIlL

]emodeglci

TUI12- II TOnne] =-j-r-U1-1-e--2----signifi- IJUlle 12- Signifi- 3 repli- 2 repli- 3 repli- Signifi-Au-( 21 ltW 3 Aug 21 Cllllce 5 Nov 3 CllIlCC 5 cates cntes u cntes cnnee 5

percent percent percent

o UmrtntecL 1 ~~ 2 ~--~ - -- ~-I-t-l----I 700L 1 980 ] G70 5lt18 b d oTnItcL---- 3(i ~ ~8middotl ____________________1__________ ---------- I J80 1070 ---------- --------- shy

~g=========1 ~ ~ ~t ~ j======i==~===~I==== ========== I ~~g ------620- ========== ====== 30___________ -1 367 UO (j 1--------------------1---------- ---------- 1820 130 ---------- --------- shy50 ____________ 11 ___ ______1__________ 17 i n GO 8 n __________ __________ G48 b d 70_______________________________ 1 middot128 n b I 6G2t b __________ ---------- J238 b e RO--- bull -o-l---------- ----- ---1 middot122 It b 660 a h __________ __________ 1180 b cDO ____________ ___ -_ _ _______ _j aD 1 b G2 0 b __________ __________ 1 noo it

100___ bull ______ 270 250 3G0 b I 013 b 2180 ---------- 2115 a bull __ bullbullbullbull __ 0_ __ bull I 0 1 ______ _0__- bullbullbulll______________________ ____-____1

bull olrlll~ fo1oed by thl SIIlW ll [N art not iJJlifi(an (Iy difflltnt middotr(Ill~ followed by different letter are significantly different gt n(plicl(~ in hilth ()ri~dnill inlro(IlNI bo1 wleil~ tlldved

_1

I

In two of the replicates where all shed forms were removed no egO punctures were found tfter August 21 and no adults after J u1y 31 Thus the infestation levels shown in figme lc after these dates are somewhat misleading representing the mfestation in only one replicate but averaged for the three The yields in the two replicates in which weeyils were controlled were 2860 and 3600 pounds of seed cotton pel acre In the Ihirc1 rep 1 icnte where the infestation was not brought under control until the end of September the yield was only 1000 pounds per acre resulting in no significant difierence between this and other treatm(nts The yield in the same replicate was also reduced by 11011worms Although c1Uferences in infestation and yield were not significant the data mdicates that reshymoval of aU shed forms at weekly intervals provided considerable control of the bon weevil uncleI conditions of this study

1959 Studies Since the studies in 1058 showed that weekly remoY[11 of 30 percent

of the shed squares did not reduce weevil populations and 100 percent removal resulted ill considerable reduction the studies in 1059 were directed at determining the lowest removal leel at 5-c1ay intervals between these extremes that Qule1 afford economic control

Removal of 50 percent of the shee1 forms was not effective in conshytrolling the boll weevil (fig 2d) Since each forl11 was present at the time of two removals at 5-day intervals before deteriorating beyond recognition the actual removal was 75 percent However removal of forms yith egg punctures actnally remained neal 50 percent since many of the weevils emerged from squares remaining in the cages beshyfore the subsequent removal (table 3) A total of 104700 forms (sqnares and bolls) per acre were mmoved by August 2G and 53D600 forms per acre were sheel During this period the equivalent of 10851 weevilf per acre emerged The effects of the early emergence of large numbers of weevils and the subsequent high infestation levels during tIle main fruiting period of the plant were mflected in the average percentages of infestation through August 21 and N ovembcr 3 and in the vield (tf1ble 2) The infestation was significantly higher than for the 90- andlOO-percent removnl levels and the yield was significantly lower These data show theinefiectiveness of a GO-percent remoyal of shed forms every 5 clays

TAIIIg ~-Total pelcentaqes oj shed f01YM jr01n which boll Weevils hacl eme1ged into the cages prior to removal of jOlrns eVeN 5 days June 19-Auguit 201959

Percentage of emergence from Percentage of forms removed

BCJuares Bolls

50_______________________________________ _ 25 3170 ________________________________________1 bull5 7 4080 ________________________________________ 1 31 37

38 ~3 I23 13~g6~=~====================================1 -----~- ----

8

SevcuLy- and ei[[hty-pclcent rcmoals (actnally D1- and DO-percent because of form presence at two re1110[1Is) showed a marked similaeshyity and were more Cffectic than the 50-percent relllomllewl (figs2e and 2f) The total number of for111S (sqllfuCs and bolls) l-ernoyec1 through August 26 (table 1) represents a shed of 187030 foems per acre in cages with the IO-percent relllovnJ rate and 524060 for the 80-percent removal rute Although this shed vas less than in the cages with 100-percent removal (30300) an carliee Ellleegence of large populations and accompanying infestation levels in early JUly occurred This is the critiml portion of the fruiting period (Fye at al)2 The ayemge infestation and yield data cleL11y indicate the middle position beteCn the fJO- ancllOO-pelcent remontlleTels The slightly 10wCl yield for the SO-percent removal ratE compnred with the 10-percent rate cnn probnbly be necounted for by 10lt(gt enused by the bollworm

Dal1 from cngCs from which DO (nclnally Dn percent bCcllnse of form presence nt two lemoyals) and 100 percCllt of the fallen forms ere removed show cOl1siclemble similltrity (figs Ie nnd 1pound) The lD1150 forms (squarCs and bolls) shed per ntlC in tIl(gt (lO-pclcentshylemontl-rnte cages does not ltpPlonch thC U30300 removed at the rnte of 100 percent but it is suspected that the subtle relnxnt iOll of weejJ prCsnrc on tiny forming squares in Ihe IOO-pCrcent-lCmoal-ratr cages and ideal growing conditions for the cotton may ncconnt for this difference nnd the differences in the numbers of squares produced with the 50- 70- and SO-percent removal rates

Consic1erntion of the nvernge infCstations nncl the Yield (tlthle 2) in the 90- and IOO-percCnt-rCmonJl series teCals little difference in the two lCnls The (lxtencled pCrioc1 of suppressed ee~il populiltions during the Cariy Tmitillg period (figs 1e and If) w11ieh mnnifests itself as the lowered infestation percentage further supports an earl ier contention (Fye et a7r thnt endy boll sci with subseqnent boll proshytect ion should be nn nc1equate control program Tor tll( boll middoteeil

CONCLUSIONS Thus from this data it mny be concluded thnt ally squarC remoal

in the field HUlst be at the rnte of 00 to 100 percent removal must be nccomplished nt 5- or fewer-clay internLls and must be mOilt eflicient in the enr1y and mid fraiting pCriod if control of the boll wPCil is to be nttaincc1

See footnote 2 p 2

9

--

~~-~ + --r~ ~f ~ ai( SjAamp r--

TJHL1~ 2--A1(I([I( p(J(enlaq( of boll 11cevil infestation and cotton yield in ca[les in whieh shed f01ms We1e

1(IIW1ed at different 7)C)cenla[le mtcs 1958-59 ~ _ ~__bull-______ ~ __ bullbull ~ _____-__ bull ___~u___ ___- ______________ --------

Yields (pound of seed cotton per ncre)Ayertge inrestation of sqllar(s

----1058 ----I In50 H)58 1959PerePIlL

]emodeglci

TUI12- II TOnne] =-j-r-U1-1-e--2----signifi- IJUlle 12- Signifi- 3 repli- 2 repli- 3 repli- Signifi-Au-( 21 ltW 3 Aug 21 Cllllce 5 Nov 3 CllIlCC 5 cates cntes u cntes cnnee 5

percent percent percent

o UmrtntecL 1 ~~ 2 ~--~ - -- ~-I-t-l----I 700L 1 980 ] G70 5lt18 b d oTnItcL---- 3(i ~ ~8middotl ____________________1__________ ---------- I J80 1070 ---------- --------- shy

~g=========1 ~ ~ ~t ~ j======i==~===~I==== ========== I ~~g ------620- ========== ====== 30___________ -1 367 UO (j 1--------------------1---------- ---------- 1820 130 ---------- --------- shy50 ____________ 11 ___ ______1__________ 17 i n GO 8 n __________ __________ G48 b d 70_______________________________ 1 middot128 n b I 6G2t b __________ ---------- J238 b e RO--- bull -o-l---------- ----- ---1 middot122 It b 660 a h __________ __________ 1180 b cDO ____________ ___ -_ _ _______ _j aD 1 b G2 0 b __________ __________ 1 noo it

100___ bull ______ 270 250 3G0 b I 013 b 2180 ---------- 2115 a bull __ bullbullbullbull __ 0_ __ bull I 0 1 ______ _0__- bullbullbulll______________________ ____-____1

bull olrlll~ fo1oed by thl SIIlW ll [N art not iJJlifi(an (Iy difflltnt middotr(Ill~ followed by different letter are significantly different gt n(plicl(~ in hilth ()ri~dnill inlro(IlNI bo1 wleil~ tlldved

_1

I

In two of the replicates where all shed forms were removed no egO punctures were found tfter August 21 and no adults after J u1y 31 Thus the infestation levels shown in figme lc after these dates are somewhat misleading representing the mfestation in only one replicate but averaged for the three The yields in the two replicates in which weeyils were controlled were 2860 and 3600 pounds of seed cotton pel acre In the Ihirc1 rep 1 icnte where the infestation was not brought under control until the end of September the yield was only 1000 pounds per acre resulting in no significant difierence between this and other treatm(nts The yield in the same replicate was also reduced by 11011worms Although c1Uferences in infestation and yield were not significant the data mdicates that reshymoval of aU shed forms at weekly intervals provided considerable control of the bon weevil uncleI conditions of this study

1959 Studies Since the studies in 1058 showed that weekly remoY[11 of 30 percent

of the shed squares did not reduce weevil populations and 100 percent removal resulted ill considerable reduction the studies in 1059 were directed at determining the lowest removal leel at 5-c1ay intervals between these extremes that Qule1 afford economic control

Removal of 50 percent of the shee1 forms was not effective in conshytrolling the boll weevil (fig 2d) Since each forl11 was present at the time of two removals at 5-day intervals before deteriorating beyond recognition the actual removal was 75 percent However removal of forms yith egg punctures actnally remained neal 50 percent since many of the weevils emerged from squares remaining in the cages beshyfore the subsequent removal (table 3) A total of 104700 forms (sqnares and bolls) per acre were mmoved by August 2G and 53D600 forms per acre were sheel During this period the equivalent of 10851 weevilf per acre emerged The effects of the early emergence of large numbers of weevils and the subsequent high infestation levels during tIle main fruiting period of the plant were mflected in the average percentages of infestation through August 21 and N ovembcr 3 and in the vield (tf1ble 2) The infestation was significantly higher than for the 90- andlOO-percent removnl levels and the yield was significantly lower These data show theinefiectiveness of a GO-percent remoyal of shed forms every 5 clays

TAIIIg ~-Total pelcentaqes oj shed f01YM jr01n which boll Weevils hacl eme1ged into the cages prior to removal of jOlrns eVeN 5 days June 19-Auguit 201959

Percentage of emergence from Percentage of forms removed

BCJuares Bolls

50_______________________________________ _ 25 3170 ________________________________________1 bull5 7 4080 ________________________________________ 1 31 37

38 ~3 I23 13~g6~=~====================================1 -----~- ----

8

SevcuLy- and ei[[hty-pclcent rcmoals (actnally D1- and DO-percent because of form presence at two re1110[1Is) showed a marked similaeshyity and were more Cffectic than the 50-percent relllomllewl (figs2e and 2f) The total number of for111S (sqllfuCs and bolls) l-ernoyec1 through August 26 (table 1) represents a shed of 187030 foems per acre in cages with the IO-percent relllovnJ rate and 524060 for the 80-percent removal rute Although this shed vas less than in the cages with 100-percent removal (30300) an carliee Ellleegence of large populations and accompanying infestation levels in early JUly occurred This is the critiml portion of the fruiting period (Fye at al)2 The ayemge infestation and yield data cleL11y indicate the middle position beteCn the fJO- ancllOO-pelcent remontlleTels The slightly 10wCl yield for the SO-percent removal ratE compnred with the 10-percent rate cnn probnbly be necounted for by 10lt(gt enused by the bollworm

Dal1 from cngCs from which DO (nclnally Dn percent bCcllnse of form presence nt two lemoyals) and 100 percCllt of the fallen forms ere removed show cOl1siclemble similltrity (figs Ie nnd 1pound) The lD1150 forms (squarCs and bolls) shed per ntlC in tIl(gt (lO-pclcentshylemontl-rnte cages does not ltpPlonch thC U30300 removed at the rnte of 100 percent but it is suspected that the subtle relnxnt iOll of weejJ prCsnrc on tiny forming squares in Ihe IOO-pCrcent-lCmoal-ratr cages and ideal growing conditions for the cotton may ncconnt for this difference nnd the differences in the numbers of squares produced with the 50- 70- and SO-percent removal rates

Consic1erntion of the nvernge infCstations nncl the Yield (tlthle 2) in the 90- and IOO-percCnt-rCmonJl series teCals little difference in the two lCnls The (lxtencled pCrioc1 of suppressed ee~il populiltions during the Cariy Tmitillg period (figs 1e and If) w11ieh mnnifests itself as the lowered infestation percentage further supports an earl ier contention (Fye et a7r thnt endy boll sci with subseqnent boll proshytect ion should be nn nc1equate control program Tor tll( boll middoteeil

CONCLUSIONS Thus from this data it mny be concluded thnt ally squarC remoal

in the field HUlst be at the rnte of 00 to 100 percent removal must be nccomplished nt 5- or fewer-clay internLls and must be mOilt eflicient in the enr1y and mid fraiting pCriod if control of the boll wPCil is to be nttaincc1

See footnote 2 p 2

9

I

In two of the replicates where all shed forms were removed no egO punctures were found tfter August 21 and no adults after J u1y 31 Thus the infestation levels shown in figme lc after these dates are somewhat misleading representing the mfestation in only one replicate but averaged for the three The yields in the two replicates in which weeyils were controlled were 2860 and 3600 pounds of seed cotton pel acre In the Ihirc1 rep 1 icnte where the infestation was not brought under control until the end of September the yield was only 1000 pounds per acre resulting in no significant difierence between this and other treatm(nts The yield in the same replicate was also reduced by 11011worms Although c1Uferences in infestation and yield were not significant the data mdicates that reshymoval of aU shed forms at weekly intervals provided considerable control of the bon weevil uncleI conditions of this study

1959 Studies Since the studies in 1058 showed that weekly remoY[11 of 30 percent

of the shed squares did not reduce weevil populations and 100 percent removal resulted ill considerable reduction the studies in 1059 were directed at determining the lowest removal leel at 5-c1ay intervals between these extremes that Qule1 afford economic control

Removal of 50 percent of the shee1 forms was not effective in conshytrolling the boll weevil (fig 2d) Since each forl11 was present at the time of two removals at 5-day intervals before deteriorating beyond recognition the actual removal was 75 percent However removal of forms yith egg punctures actnally remained neal 50 percent since many of the weevils emerged from squares remaining in the cages beshyfore the subsequent removal (table 3) A total of 104700 forms (sqnares and bolls) per acre were mmoved by August 2G and 53D600 forms per acre were sheel During this period the equivalent of 10851 weevilf per acre emerged The effects of the early emergence of large numbers of weevils and the subsequent high infestation levels during tIle main fruiting period of the plant were mflected in the average percentages of infestation through August 21 and N ovembcr 3 and in the vield (tf1ble 2) The infestation was significantly higher than for the 90- andlOO-percent removnl levels and the yield was significantly lower These data show theinefiectiveness of a GO-percent remoyal of shed forms every 5 clays

TAIIIg ~-Total pelcentaqes oj shed f01YM jr01n which boll Weevils hacl eme1ged into the cages prior to removal of jOlrns eVeN 5 days June 19-Auguit 201959

Percentage of emergence from Percentage of forms removed

BCJuares Bolls

50_______________________________________ _ 25 3170 ________________________________________1 bull5 7 4080 ________________________________________ 1 31 37

38 ~3 I23 13~g6~=~====================================1 -----~- ----

8

SevcuLy- and ei[[hty-pclcent rcmoals (actnally D1- and DO-percent because of form presence at two re1110[1Is) showed a marked similaeshyity and were more Cffectic than the 50-percent relllomllewl (figs2e and 2f) The total number of for111S (sqllfuCs and bolls) l-ernoyec1 through August 26 (table 1) represents a shed of 187030 foems per acre in cages with the IO-percent relllovnJ rate and 524060 for the 80-percent removal rute Although this shed vas less than in the cages with 100-percent removal (30300) an carliee Ellleegence of large populations and accompanying infestation levels in early JUly occurred This is the critiml portion of the fruiting period (Fye at al)2 The ayemge infestation and yield data cleL11y indicate the middle position beteCn the fJO- ancllOO-pelcent remontlleTels The slightly 10wCl yield for the SO-percent removal ratE compnred with the 10-percent rate cnn probnbly be necounted for by 10lt(gt enused by the bollworm

Dal1 from cngCs from which DO (nclnally Dn percent bCcllnse of form presence nt two lemoyals) and 100 percCllt of the fallen forms ere removed show cOl1siclemble similltrity (figs Ie nnd 1pound) The lD1150 forms (squarCs and bolls) shed per ntlC in tIl(gt (lO-pclcentshylemontl-rnte cages does not ltpPlonch thC U30300 removed at the rnte of 100 percent but it is suspected that the subtle relnxnt iOll of weejJ prCsnrc on tiny forming squares in Ihe IOO-pCrcent-lCmoal-ratr cages and ideal growing conditions for the cotton may ncconnt for this difference nnd the differences in the numbers of squares produced with the 50- 70- and SO-percent removal rates

Consic1erntion of the nvernge infCstations nncl the Yield (tlthle 2) in the 90- and IOO-percCnt-rCmonJl series teCals little difference in the two lCnls The (lxtencled pCrioc1 of suppressed ee~il populiltions during the Cariy Tmitillg period (figs 1e and If) w11ieh mnnifests itself as the lowered infestation percentage further supports an earl ier contention (Fye et a7r thnt endy boll sci with subseqnent boll proshytect ion should be nn nc1equate control program Tor tll( boll middoteeil

CONCLUSIONS Thus from this data it mny be concluded thnt ally squarC remoal

in the field HUlst be at the rnte of 00 to 100 percent removal must be nccomplished nt 5- or fewer-clay internLls and must be mOilt eflicient in the enr1y and mid fraiting pCriod if control of the boll wPCil is to be nttaincc1

See footnote 2 p 2

9

SevcuLy- and ei[[hty-pclcent rcmoals (actnally D1- and DO-percent because of form presence at two re1110[1Is) showed a marked similaeshyity and were more Cffectic than the 50-percent relllomllewl (figs2e and 2f) The total number of for111S (sqllfuCs and bolls) l-ernoyec1 through August 26 (table 1) represents a shed of 187030 foems per acre in cages with the IO-percent relllovnJ rate and 524060 for the 80-percent removal rute Although this shed vas less than in the cages with 100-percent removal (30300) an carliee Ellleegence of large populations and accompanying infestation levels in early JUly occurred This is the critiml portion of the fruiting period (Fye at al)2 The ayemge infestation and yield data cleL11y indicate the middle position beteCn the fJO- ancllOO-pelcent remontlleTels The slightly 10wCl yield for the SO-percent removal ratE compnred with the 10-percent rate cnn probnbly be necounted for by 10lt(gt enused by the bollworm

Dal1 from cngCs from which DO (nclnally Dn percent bCcllnse of form presence nt two lemoyals) and 100 percCllt of the fallen forms ere removed show cOl1siclemble similltrity (figs Ie nnd 1pound) The lD1150 forms (squarCs and bolls) shed per ntlC in tIl(gt (lO-pclcentshylemontl-rnte cages does not ltpPlonch thC U30300 removed at the rnte of 100 percent but it is suspected that the subtle relnxnt iOll of weejJ prCsnrc on tiny forming squares in Ihe IOO-pCrcent-lCmoal-ratr cages and ideal growing conditions for the cotton may ncconnt for this difference nnd the differences in the numbers of squares produced with the 50- 70- and SO-percent removal rates

Consic1erntion of the nvernge infCstations nncl the Yield (tlthle 2) in the 90- and IOO-percCnt-rCmonJl series teCals little difference in the two lCnls The (lxtencled pCrioc1 of suppressed ee~il populiltions during the Cariy Tmitillg period (figs 1e and If) w11ieh mnnifests itself as the lowered infestation percentage further supports an earl ier contention (Fye et a7r thnt endy boll sci with subseqnent boll proshytect ion should be nn nc1equate control program Tor tll( boll middoteeil

CONCLUSIONS Thus from this data it mny be concluded thnt ally squarC remoal

in the field HUlst be at the rnte of 00 to 100 percent removal must be nccomplished nt 5- or fewer-clay internLls and must be mOilt eflicient in the enr1y and mid fraiting pCriod if control of the boll wPCil is to be nttaincc1

See footnote 2 p 2

9

t

----shy ~