Utilization of the Boll Weevil Pheromone for Insect Control - ACS

2 Utilization of the Boll Weevil Pheromone for

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Insect Control P. A. HEDIN, R. C. GUELDNER, and A. C. THOMPSON USDA, BWRL, ARS, So. Region, Miss. State, Ms. 39762

The boll weevil, Anthonomus grandis Boheman, was introduced from Mexico into the United States (near Brownsville, Texas) about 1892 (1). "Figure 1". By 1922 the pest had spread into cotton-growing areas of the United States from the eastern two-thirds of Texas and Oklahoma to the Atlantic Ocean. Its recent extension i n to west Texas now threatens cotton in New Mexico, Northwestern Mexico, Arizona and California. As early as 1895, recognition of the tremendous damage caused by this insect was noted, and Town send (2) suggested that cotton growing be terminated in the region then infested and that a cotton-free zone be maintained along the Rio Grande River bordering Mexico. Several other entomologists studied and suggested ways to control the boll weevil. Howard (3) reported on the use of and lack of response to light traps. Malley (4) studied the use of poisons for weevil control as well as the use of cotton as trap plants. An act was passed by the Texas legislature in 1903 offering $50,000 as a cash reward for a practical way to control the boll weevil. Sanderson (5) reported that hand picking of infested squares had been tried and was meeting with little success. "Figure 2". Hunter (6) made the following statement : "It is concluded that there is not even a remote possibility that the boll weevil w i l l be eradicated." Since that time, numerous methods of control have been tested and reported, 71 years have elapsed, and the boll weevil still has not been eradicated. From 1917 until the late 1940's the most effective method of control was dusting with calcium arsenate (7) (8). The development of DDT and other chlorinated hydrocarbons during World War II made a completely new group of insecticides available for controlling many insect pests including the boll weevil (9). However, in 1954 scientists in Louisiana reported that boll weevils were becoming resistant to the chlorinated hydrocarbons (10), and within two years resistance was widespread throughout the Cotton Belt. The organophosphate insecticides have been successfully used since then to control boll weevils without resistance problems. However, $70 million is spent annually for boll weevil control, 30

Beroza; Pest Management with Insect Sex Attractants ACS Symposium Series; American Chemical Society: Washington, DC, 1976.


HEDIN ET AL.

Boll Weevil Pheromone

Figure 1.

Figure 2.



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PEST MANAGEMENT WITH INSECT SEX

ATTRACTANTS

and the pest s t i l l causes an estimated $200 m i l l i o n i n crop l o s s e s each year (11)(12). In recent years, these f i g u r e s may have increased by 50% because of i n f l a t i o n , even w i t h 10-20% l e s s cotton grown. More than t h r e e - f o u r t h s of a l l i n s e c t l o s s e s to cotton i n the United States have been a t t r i b u t e d to the b o l l w e e v i l . I t i s gene r a l l y agreed that cotton cannot be p r o f i t a b l y grown i n areas where the i n s e c t cannot be c o n t r o l l e d . Coker (13) estimated that 64,877,000 bales of cotton and 27,917,000 tons of cottonseed valued at $7,680,000,000 were destroyed by the w e e v i l from 1909 to 1954. Approximately o n e - t h i r d of the i n s e c t i c i d e used f o r a g r i c u l t u r e i n the United States i s r e quired f o r b o l l w e e v i l c o n t r o l (14). In recent years, the cotton i n d u s t r y has been confronted w i t h major competition from the s y n t h e t i c f i b e r i n d u s t r y , which has penet r a t e d markets that h i s t o r i c a l l y have belonged to American cotton producers. Competition i s a l s o f e l t from f o r e i g n cottons. In order to maintain cotton i n a competitive p o s i t i o n , the United States Congress has provided r e l i e f i n two areas. (1) From the e a r l y 1950 s u n t i l 1973, growers were s u b s i d i z e d to the extent of approximately $0.10 per pound, which allowed them to compete w i t h f o r e i g n cotton that s o l d f o r approximately $0.20 per pound u n t i l 1970-2. However, Congress no longer provides p r i c e supports, and the current domestic p r i c e of about $0.45 per pound (June 1975) i s a l s o the world p r i c e . (2) Research was i n t e n s i f i e d approximately 15 years ago to improve y i e l d s of cotton and to decrease costs of production. One p a r t of t h i s program has been an e f f o r t to c o n t r o l the b o l l w e e v i l w h i l e decreasing the dependence on i n s e c t i c i d e s . Another part has i n v o l v e d e r a d i c a t i n g the i n s e c t from the United S t a t e s . Funds were provided to i n t e n s i f y research at e x i s t i n g f a c i l i t i e s and for the construction and staffing of a larger cent r a l l a b o r a t o r y at State College (now Miss. S t a t e ) , M i s s i s s i p p i . Since then, the technology f o r an i n t e g r a t e d e f f o r t to e l i m i n a t e the b o l l w e e v i l has been developed by s c i e n t i s t s at t h i s and other l a b o r a t o r i e s . This r e p o r t describes work l e a d i n g to the i d e n t i f i c a t i o n , s y n t h e s i s , and u t i l i z a t i o n of the b o l l w e e v i l pheromone (common name: grandlure f o r A. grandis Boh.) as an i n t e g r a l part of an attempt to e l i m i n a t e the b o l l w e e v i l from the Cotton B e l t . 1

B i o l o g y of the B o l l Weevil Pheromone: In the e a r l i e s t record of b o l l w e e v i l mating, Hunter and Hinds (1) concluded that females were not a t t r a c t i v e to males and that ". . . i n s t e a d of seeking widely f o r the females, the males are content to wait f o r them to come t h e i r way." I t was not u n t i l 1962 that Cross and M i t c h e l l (15), confirmed by K e l l e r et a l . (16), showed c o n c l u s i v e l y that the male b o l l w e e v i l produces a wind-borne sex a t t r a c t a n t (pheromone) that i s a t t r a c t i v e to females. In 1967 Cross and Hardee (17) demonstrated f o r the f i r s t time, Bradley et a l . (18) confirmed, and Hardee et a l . (19)showed i n de-


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t a i l that the pheromone of the male b o l l w e e v i l i s not only a sex pheromone f o r females but a l s o acts as an aggregating pheromone for both sexes, p r i m a r i l y i n the s p r i n g and f a l l and to a l e s s e r degree i n mid-season. I n 1968, Hardee e t a l . (20) confirmed the aggregating c h a r a c t e r i s t i c o f the pheromone and s t u d i e d i n the f i e l d the i n f l u e n c e of d i e t on the production of the pheromone.


I s o l a t i o n and

Identification

The f i r s t i s o l a t i o n (16) of the sex a t t r a c t a n t was accomp l i s h e d by drawing a i r from caged males through a column of a c t i vated c h a r c o a l . A chloroform e x t r a c t of the charcoal l e f t a r e sidue to which female weevils q u i c k l y responded i n a l a b o r a t o r y t e s t . Other i s o l a t i o n methods (21) i n v e s t i g a t e d i n c l u d e d aerat i o n , solvent e x t r a c t i o n , column chromatography of s o l v e n t e x t r a c t s , and steam d i s t i l l a t i o n of dichloromethane e x t r a c t s . The l a t t e r was the most s u i t a b l e . E x t r a c t i o n s and f u r t h e r p u r i f i c a t i o n s from f e c a l m a t e r i a l and i n s e c t s were c a r r i e d out i n i d e n t i c a l f a s h i o n . Each step was moni t o r e d by l a b o r a t o r y bioassay (22) of i n d i v i d u a l f r a c t i o n s and combinations o f v a r i o u s f r a c t i o n s . "Figure 3". Insects (67,000 males and 4,500,000 weevils of mixed sexes) o r f e c a l m a t e r i a l (54.7 kg) were e x t r a c t e d w i t h dichloromethane; the e x t r a c t was steam d i s t i l l e d , the d i s t i l l a t e was e x t r a c t e d w i t h d i c h l o r o methane, and the solvent was again removed under vacuum. The e x t r a c t of the steam d i s t i l l a t e from weevils and t h e i r feces was f r a c t i o n a t e d by column chromatography on Carbowax 20M coated s i l i c a g e l . None of the i n d i v i d u a l f r a c t i o n s from t h i s column were a t t r a c t i v e to females, but the combination of two o f the f r a c t i o n s was as a c t i v e as the o r i g i n a l d i s t i l l a t e . Each o f these two f r a c t i o n s was then s e p a r a t e l y f r a c t i o n a t e d on a column c o n t a i n i n g Adsorbosil-CABN (25% AgN03 on s i l i c a g e l ) . Various recombinations of a l l the f r a c t i o n s from both AgN03~ s i l i c a g e l columns y i e l d e d two f r a c t i o n s , one from each column, that were a t t r a c t i v e together but almost t o t a l l y u n a t t r a c t i v e sepa r a t e l y . Each of these l a t t e r two a c t i v e f r a c t i o n s was then f r a c t i o n a t e d by g l c on Carbowax 4000 and SE-30. Three components were c o l l e c t e d that were a t t r a c t i v e when a l l three were combined but that were u n a t t r a c t i v e i n d i v i d u a l l y or i n p a i r s . Rechromatography on Carbowax 4000, SE-30, and a 5 0 - f t support-coated open t u b u l a r (SCOT) column showed two of these components to be pure I and I I and the t h i r d t o c o n s i s t of two compounds, I I I , and IV. Concent r a t i o n s o f compounds I , I I , I I I , and IV i n f e c a l m a t e r i a l , d e t e r mined by g l c , were 0.76, 0.57, 0.06 and 0.06 ppm. Concentrations i n w e e v i l s were about t e n f o l d l e s s . Compound I was i d e n t i f i e d as (+)c?is-2-isopropenyl-l-methylcyclobutaneethanol on the b a s i s of mass, i r , and nmr s p e c t r a . The c o n f i g u r a t i o n was assigned by comp a r i s o n w i t h the nmr spectrum of the s y n t h e t i c c i s isomer. The s t r u c t u r e of compound I I (Z)-3^-dimethylA »^-cyclohexaneethanol was e l u c i d a t e d on the b a s i s o f i t s mass, nmr, and i r s p e c t r a and 1



PEST MANAGEMENT WITH INSECT SEX ATTRACTANTS

Figure 3.

OH

(I)

(ii)

(in)

(IV)

Figure 4.


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w i t h f u r t h e r evidence obtained from i t s p a l l a d i u m c a t a l y s t reduct i o n and o z o n o l y s i s . The s t r u c t u r e s of compounds I I I (Z)-3,3-dimethyl-A > -cyclohexaneacetaldehyde) and IV ( E ) - 3 ^ - d i m e t h y l - A - c y c l o h e x a n e a c e taldehyde) were deduced from the f o l l o w i n g i n f o r m a t i o n . When compounds I I I and IV were e l u t e d as a s i n g l e peak from a g l c column i n t o 2,4-dinitrophenylhydrazine reagent on a TLC p l a t e , a d e r i v a t i v e was produced that had an Rf s i m i l a r t o that of standard terpene carbonyls. The mass s p e c t r a of compounds I I I and IV were n e a r l y i d e n t i c a l w i t h each other and s i m i l a r t o compound I I . The parent peak had a m/e of 152 i n both cases, app r o p r i a t e f o r a monocyclic terpene aldehyde or ketone w i t h one u n s a t u r a t i o n . Reduction of compounds I I I and IV at the i n l e t of a gas chromatograph produced only one peak w i t h a parent mass of 154, which confirmed the s i n g l e u n s a t u r a t i o n . The base peak i n the spectrum of s a t u r a t e d I I I and IV, m/e 110, suggested a f a c i l e l o s s of the elements o f acetaldehyde. The d e t a i l s o f the s t r u c t u r a l e l u c i d a t i o n s were given i n the r e p o r t s by Tumlinson e t a l . (23., 24), "Figure 4." 1

a


1,ot

Synthesis of the B o l l Weevil Pheromone Compounds The f i r s t s y n t h e s i s of compound I that confirmed the proposed s t r u c t u r e was reported by Tumlinson et a l . i n 1969 (23). A s l i g h t l y m o d i f i e d procedure i s i l l u s t r a t e d i n Scheme I ("Figure 5"), the d e t a i l s of which are reported by Tumlinson et a l . (24). Since these syntheses were r e p o r t e d , s e v e r a l others have been devised by workers i n t h i s country and i n Europe. U n t i l 1973, an improved s y n t h e s i s by Gueldner et a l . (25) was employed to prépare approximately 1 kg. f o r f i e l d s t u d i e s . This method has been replaced by a 2-step s y n t h e s i s of B i l l u p s e t a l . (26) i n which an isoprene d i m e r i z a t i o n g i v e s s e v e r a l products, one of which i s converted t o the d e s i r e d product when subjected to hydroboration. The syntheses o f Compounds I I , I I I and IV are summarized i n Scheme I I ("Figure 6"). Furthur d e t a i l s are i n c l u d e d i n the r e p o r t s o f Tumlinson et a l . (23,24). I n i t i a l l y , approximately 300g of each of these components were prepared f o r f i e l d s t u d i e s by t h i s procedure. However, the procedures have now been substanti a l l y r e v i s e d by each of s e v e r a l vendors who prepare these compounds f o r f i e l d t e s t s . As w i t h compound I , a number of new syntheses have been p u b l i s h e d by chemists i n t h i s country and elsewhere. B i o s y n t h e s i s of the B o l l Weevil Pheromone Compounds Before the pheromones had been i d e n t i f i e d , i t was e s t a b l i s h ed that males needed t o f e e d , p r e f e r a b l y on c o t t o n , to become a t t r a c t i v e . Hardee et a l . (22), B a r t l e t t e t a l . (27) , and Hardee et a l . (28) reported that the peak s e x u a l a c t i v i t y of both males


36



CH

4 ^

+

PhCOCHà

Ο Me Mg

3

CH

3

I N

B2 H 6 H O2 OH2

Η

OH

CH OH

Ag Q 2

3

y

L1AIH4

Figure 5.


OH



HEDIN ET AL.

Figure 6.



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ATTRACTANTS

and females d i d not occur u n t i l the w e e v i l s were 4 to 6 days o l d , and comparisons between l a b o r a t o r y - r e a r e d and n a t i v e w e e v i l s i n d i c a t e d food to be of greater importance than c u l t u r e i n d e t e r mining female response. A d d i t i o n a l d i e t s t u d i e s i n the l a b o r a t o r y and f i e l d i n 1966-69 by Hardee (29) showed t h a t : (1) Males fed c o t t o n squares, b o l l s , and blooms were c o n s i d e r a b l y more a t t r a c t i v e than males fed t e r m i n a l s , cotyledons, and l e a v e s ; (2) pheromone production by males was reduced by about 50 percent one hour and over 90 percent twenty-four hours a f t e r food was removed; (3) males s u r v i v e d w e l l and produced pheromone i n l a b o r a t o r y bioassays on a v a r i e t y of foods (50-70 percent as much as on cotton squares) such as apples, bananas, o k r a , peaches, and s t r i n g beans, but the most f a v o r a b l e d i e t was c o t t o n squares; and (4) overwintered male b o l l w e e v i l s s u r v i v e d longer without food than l a b o r a t o r y - r e a r e d males, but both needed some food before pheromone production began. In f i e l d t e s t s however, Cross et a l . (unpublished data) were not able to show response to male b o l l w e e v i l s fed on any d i e t except c o t t o n . The r e s u l t s i n d i c a t e d that a constant supply of adequate food, p r e f e r a b l y c o t t o n squares or s m a l l cotton b o l l s , i s e s s e n t i a l to continued production of a high l e v e l of pheromone by males. Tumlinson et a l . (23) c a l c u l a t e d that compounds I , I I , I I I , and IV were present i n feces of mixed sexes at concentrations of 0.76, 0.57, 0.06 and 0.06 ppm (13:9:1:1) r e s p e c t i v e l y . Hedin et a l . (30) found t h a t the t o t a l content of the components i n males i s 200 ng or l e s s but that the average content i n the f r a s s produced during 1 day i s 1268 ng; the l i f e t i m e production may be 40,000 ng. The r a t i o of the four components i n male f r a s s was 6 : 6 : 2 : 1 / I : I I : I I I : I V . None of the four components was found i n females, but female f r a s s contained t r a c e s i n three i n s t a n c e s , probably because of contamination w i t h males. The b i o s y n t h e s i s i s n e g l i g i b l e immediately a f t e r a d u l t emergence and increases to a maximum r a t e by day 8, which i s e s s e n t i a l l y maintained f o r the remainder of the l i f e t i m e of the i n s e c t s . Even though males must feed, p r e f e r a b l y on c o t t o n , to a t t r a c t females, M i t l i n and Hedin (31) showed that the b i o s y n t h e s i s of the pheromone components was de novo : When the s t e a m - d i s t i l l e d feces of a d u l t males that had been i n j e c t e d w i t h a c e t a t e - l ^ C , a c e t a t e 2^C or glucose -^C(U) was f r a c t i o n a t e d by column and gas chromatography, approximately 0.02% of the administered r a d i o a c t i v i t y was i n c o r p o r a t e d i n t o the v o l a t i l e f r a c t i o n , a t y p i c a l percent i n c o r p o r a t i o n of these precursors i n t o monoterpenes by p l a n t s . The 4 components comprised 57 to 80% of the r a d i o a c t i v i t y of the v o l a t i l e s but only 39% of the t o t a l content of the v o l a t i l e s . Although the b o l l w e e v i l i s e s s e n t i a l l y an o b l i g a t e i n s e c t of c o t t o n , t h i s i n s e c t does not appear to r e q u i r e any s p e c i f i c component i n c o t t o n f o r b i o s y n t h e s i s of the pheromone. Nevertheless, some c o n s t i t u e n t i n c o t t o n may be e f f i c i e n t l y converted to the pheromones. Tumlinson et a l . (32) has devised a h y p o t h e t i c a l scheme i n which a myrcene precursor such as g e r a n i o l 9



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could be converted i n t o a l l four a c t i v e components. ("Figure 7"). Myrcene and 3-ocimene are major c o n s t i t u e n t s of the cotton bud e s s e n t i a l o i l (33). Ten other monoterpene hydrocarbons (33) s e v e r a l monoterpene a l c o h o l s (34), and myrtenal (35) have a l s o been found i n cotton buds. For r e s o l u t i o n of t h i s question of p r e c u r s o r s , the a d m i n i s t r a t i o n of i^C-monoterpenoids seems indicated. In recent work, Hedin et a l . (36) showed that cotton buds promoted a higher l e v e l of pheromone b i o s y n t h e s i s by the i n s e c t s than d i d the l a b o r a t o r y d i e t , mostly because w e e v i l s fed the l a b o r a t o r y d i e t produced l e s s e r amounts o f the aldehydes ( I I I and I V ) . Unpublished work w i t h P. P. Sikerowski (Miss. State Entomology Dept.) appeared to show that f o r a p e r i o d i n the l a t e f a l l of 1974 germ-free i n s e c t s fed the l a b o r a t o r y d i e t produced as much pheromone as i n s e c t s fed buds and f a r more than b a c t e r i a l l y contaminated i n s e c t s (5,000 c o l o n i e s per i n s e c t ) fed the l a b o r a t o r y d i e t . However, during January through A p r i l 1975, very l i t t l e pheromone was b i o s y n t h e s i z e d by i n s e c t s on buds o r any d i e t . In May and June, pheromone b i o s y n t h e s i s returned t o the higher l e v e l s of previous summers. Although the l a b o r a t o r y s t r a i n employed here does not a t t a i n f i r m diapause as do f i e l d c o l l e c t e d i n s e c t s , l a b o r a t o r y bioassays have always proved e r r a t i c each w i n t e r , and the apparent seasonal f l u c t u a t i o n s o f pheromone b i o s y n t h e s i s may have a r e a l b a s i s . The matter of b a c t e r i a l gut contamination i s a l s o o f i n t e r est because R. McLaughlin (BWRL, p r i v a t e communication) has shown that l a r v a e r e s i d i n g i n f a l l e n cotton squares (buds) are f r e e of microorganisms. A d u l t s that emerge from squares and feed on squares as a d u l t s g e n e r a l l y have l i t t l e contamination, but a d u l t s fed squares a f t e r having been reared on a contaminated l a b o r a t o r y d i e t remain contaminated (P. P. S i k e r o w s k i , MSU Ent. Dept., p r i v a t e communication). While the pheromone b i o s y n t h e s i s o f i n s e c t s maintained on these v a r i o u s regimens has not been analyzed i n d i r e c t comparisons, the e x p e c t a t i o n i s that the optimum b i o s y n t h e s i s would be achieved by m i c r o b i a l l y s t e r i l e males that were reared from buds and subsequently fed on buds. On the assumption that the cotton p l a n t contained some bact e r i a l suppressants that acted to maintain the n a t i v e i n s e c t f r e e of gut b a c t e r i a , cotton bud e x t r a c t s were prepared that d i d t o t a l l y suppress the growth of B a c i l l u s t h u r i n g e n s i s B e r l i n e r i n p e t r i p l a t e t e s t s . However, these e x t r a c t s when added to b o l l w e e v i l l a r v a l and a d u l t d i e t s were only marginal i n t h e i r a b i l i t y to suppress i n s e c t gut b a c t e r i a l f l o r a (P. A. Hedin, P. P. S i k e r o w s k i , 0. H. L i n d i g , unpublished d a t a ) . Cotton bud c o n s t i t u e n t s , t h e r e f o r e , do not appear to d i r e c t l y c o n t r o l e i t h e r pheromone b i o s y n t h e s i s or the gut m i c r o b i o l o g i c a l p o p u l a t i o n , and the e f f e c t o f the gut f l o r a on pheromone b i o s y n t h e s i s seems to be secondary and r e l a t e d to general i n s e c t h e a l t h . A l t e r n a t i v e l y , the cotton bud c o n s t i t u e n t s may mediate the establishment of a




Myrcene precursor

^ ^ C H

(IV)

(m) Figure 7.


2

O H


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m i c r o b i a l p o p u l a t i o n f a v o r a b l e t o pheromone b i o s y n t h e s i s . The o v e r a l l i n d i c a t i o n that germ-free i n s e c t s produce more pheromone i s i n apparent c o n t r a s t t o the work of Brand e t a l . (37) who r e ported that they had i s o l a t e d a number of microorganisms from the gut of males o f Ips paraconfusus L a n i e r and found that some are able t o convert alpha-pinene t o the pheromones, c i s and t r a n s verb e n o l . I t has a l s o been of i n t e r e s t t o determine whether i n s e c t s that have been s t e r i l i z e d b i o s y n t h e s i z e as much pheromone as do normal males. B a r t l e t t e t a l . (27) showed that males s t e r i l i z e d w i t h apholate o r gamma i r r a d i a t i o n were as a t t r a c t i v e as unt r e a t e d males when both were fed cotton buds. Klassen and E a r l e (38) showed w i t h f i e l d trap t e s t s that the treatment of male b o l l w e e v i l s w i t h the c h e m o s t e r i l a n t , b u s u l f a n , d i d not reduce pheromone p r o d u c t i o n . However, i n extensive f i e l d t e s t s where Tnales that had been c h e m o s t e r i l i z e d i n the mass r e a r i n g f a c i l i t y were r e l e a s e d f o r the purpose of mating w i t h untreated females, they were not competitive w i t h untreated males (39) and experienced r a p i d m o r t a l i t y . Recently, however, i n s e c t s o f both sexes have been s t e r i l i z e d s u c c e s s f u l l y as pupae by exposing them to a s e r i e s of 25 doses of gamma r a d i a t i o n a t 4 hour i n t e r v a l s o f 250 rads each. These t r e a t e d w e e v i l s have an acceptable l e v e l of mort a l i t y , and they appear t o be competitive w i t h untreated males. Presumably they t h e r e f o r e produce as much pheromone ( M i t l i n and Haynes BWRL, p r i v a t e communication) There a r e , t h e r e f o r e , many f a c t o r s that may modify pheromone production. The d i e t appears to be the main f a c t o r , but b a c t e r i a l contamination of the gut, age, presence of females, season of the year, and treatment w i t h drugs are some of the other c o n t r i b u t i n g factors. Formulation of the B o l l Weevil Pheromone For F i e l d U t i l i z a t i o n In i n i t i a l l a b o r a t o r y bioassays during 1967-9 o f f r a c t i o n s and s y n t h e t i c m a t e r i a l s , the components i n pentane s o l u t i o n were impregnated on f i r e b r i c k (23) i n a r a t i o o f approximately 1:1:1:1/ I : I I : I I I : I V . Hardee e t a l . (40) found that there was a c t u a l l y q u i t e a l a t i t u d e i n r a t i o s that were a t t r a c t i v e and that i n f i e l d t e s t s , increased percentages of the a l c o h o l s r e l a t i v e t o the a l dehydes s i g n i f i c a n t l y improved performance. Combinations cons i s t i n g of 2:6:1:1, 3:5:1:1, and 40:30:15:15/I:II:III:IV were the most promising. I t i s t h e r e f o r e p o s s i b l e to s e l e c t a r a t i o of components based on l e a s t c o s t . A f t e r s y n t h e s i s , the aldehydes are d i l u t e d w i t h pentane f o r storage. The a l c o h o l s can be s t o r e d as the neat l i q u i d s . As a p r e c a u t i o n , which i s not completely necessary, a l l the components are r e f r i g e r a t e d u n t i l formulated. A l s o , the formulations are r e f r i g e r a t e d u n t i l they are used i n the f i e l d . Approximately 75 grams o f each component was synthesized i n house i n i t i a l l y . Since then, the pheromones have been procured


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from c o n t r a c t o r s . The s p e c i f i c a t i o n s c a l l f o r 95% p u r i t y , and the components are analyzed on r e c e i p t by g l c w i t h a 250 f t X 0.03 i n . c a p i l l a r y column coated w i t h OV-17 prepared by Gueldner (unpubl i s h e d d a t a ) . Compound I as p r e s e n t l y prepared by the B i l l u p s (26) procedure i s a 1:1 mixture of o p t i c a l isomers plus minor p o s i t i o n a l isomers. The predominant i m p u r i t y of compound I I i s the IS isomer. Three major i m p u r i t i e s a l l r e s u l t i n g from o x i d a t i o n of compounds I I I and IV, are 3,3-dimethylcyclohexanecarboxaldehyde, ( Z ) - 3 ^ - d i m e t h y l - A > - c y c l o h e x a n e a c e t i c a c i d (and the 12 isomer) , and (Z^)-3,3-dimethyl-A > -cyclohexanemethanol f o r mate (and the IS isomer) (R. D. Henson, unpublished d a t a ) . In 1969-70, grandlure was compared i n 6 formulations i n traps i n the f i e l d w i t h males as f o l l o w s : 1) d i s s o l v e d i n d i c h l o r o methane i n polyethylene caps, 2) impregnated on f i r e b r i c k i n perf o r a t e d cardboard p i l l b o x e s , w i t h and without water added to s a t u r a t i o n ; 3) formulated i n nylon r e s i n o r polyethylene g l y c o l 1000 t a b l e t s (41); 4) formulated w i t h g l y c e r o l , water, methanol, and polyethylene g l y c o l 1000 a t v a r i o u s concentrations and absorbed i n cotton d e n t a l wicks (42). I n i t i a l r e s u l t s w i t h the v a r i o u s formulations were p o s i t i v e only when water was added to f i r e b r i c k or when the cotton d e n t a l wick f o r m u l a t i o n was used. I n these f o r m u l a t i o n s , grandlure was competitive w i t h males a t f a i r l y high dosages but f o r only 2 days o r l e s s , i n d i c a t i o n of the need f o r a slow-release f o r m u l a t i o n . Other formulations that had shown promise i n l a b o r a t o r y b i o assays were evaluated f u r t h e r i n the f i e l d i n 1970 by comparing the response of r e l e a s e d , l a b o r a t o r y - r e a r e d females to square-fed males or to formulated grandlure i n t r a p s . The formulations were as f o l l o w s : grandlure impregnated on a d e n t a l r o l l dipped i n melted p a r a f f i n ; grandlure + Tenox , an a n t i o x i d a n t , added to a nylon r e s i n - c l a y s l u r r y , and pressed i n t o p e l l e t s ; same as previous but without Tenox; grandlure added to a v a s e l i n e - c l a y s l u r r y and pressed i n t o p e l l e t s s i m i l a r to the previous. A l l of the formulations t e s t e d except the v a s e l i n e - c l a y mixture were competitive w i t h males the f i r s t day, but only the nylon r e s i n c l a y t a b l e t plus a n t i o x i d a n t was a c t i v e a f t e r the 3rd day. However, when the l a t t e r f o r m u l a t i o n was compared w i t h males by r e l e a s i n g females i n the f i e l d i n south F l o r i d a , i t was not a t a l l competitive w i t h males. A l s o a polyethylene g l y c o l t a b l e t f o r m u l a t i o n that was very e f f e c t i v e i n l a b o r a t o r y bioassays was i n e f f e c t i v e i n f i e l d t e s t s i n south M i s s i s s i p p i when the dry t a b l e t was used but was n e a r l y competitive w i t h males when water was added to the t a b l e t (42). The increased a c t i v i t y obtained by adding water to the f i r e b r i c k impregnated w i t h grandlure and a n t i o x i d a n t to the nylon r e s i n f o r m u l a t i o n suggested that the water prevented the o x i d a t i o n of the aldehydes i n grandlure to a c i d s and consequently prolonged the a c t i v i t y of grandlure i n the f i e l d . This then stimul a t e d the development of a water-containing f o r m u l a t i o n w i t h a slow-release agent (polyethylene g l y c o l - 1 0 0 0 ) , a humectant ( g l y 1

a


1

a

R



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c e r o l ) , and a d i l u e n t (methanol) i n the f o l l o w i n g proportions : water 12.5, polyethylene g l y c o l 12.5, g l y c e r o l 25, and methanol 50. Grandlure was incorporated i n t o t h i s mixture at a concentra t i o n of about 1.6 mg per ml, and then 0.5 ml of the t o t a l mixture was d e l i v e r e d to a preformed 5/16 i n . X 3/4-in. wick prepared from a c o t t o n d e n t a l r o l l ( l a t e r changed to a c i g a r e t t e f i l t e r ) . This f o r m u l a t i o n was very competitive w i t h males fed squares i n t e s t s , but no more than 4 days a c t i v i t y was a t t a i n a b l e (42). Beginning i n 1971, grandlure was provided t o s e v e r a l p r i v a t e companies f o r f o r m u l a t i o n by t h e i r e x i s t i n g processes. An e x p e r i mental gel-type f o r m u l a t i o n submitted by Zoecon Corporation, Palo A l t o , C a l i f . , was 90-100% as e f f e c t i v e as males i n f i e l d t r i a l s over a seven day p e r i o d (43). I n 1972 B u l l et a l . (44) improved the c i g a r e t t e f i l t e r f o r m u l a t i o n of Hardee et a l . (42) by p l a c i n g the f i l t e r s impregnated w i t h grandlure i n s i d e a glass v i a l to pro v i d e a p h y s i c a l b a r r i e r to evaporation and p h y s i c a l breakdown. Because the open end o f the v i a l was a r e s t r i c t e d opening, a par t i a l e q u i l i b r i u m e x i s t e d w i t h i n the v i a l i n which the c i g a r e t t e f i l t e r occupied n e a r l y a l l the space, and the r a t e o f l o s s over an extended p e r i o d (2-3 weeks) was n e a r l y l i n e a r as determined by g l c (McKibben, unpublished data). I n c o n t r a s t , the r a t e of l o s s from a c i g a r e t t e f i l t e r not placed i n a v i a l was l o g a r i t h m i c . This f o r m u l a t i o n , known as the "BC" f o r m u l a t i o n , was used widely i n 1973 and 1974 i n 13 cotton-growing s t a t e s and 5 f o r e i g n coun t r i e s f o r survey and management o f the b o l l w e e v i l , as w e l l as i n the P i l o t B o l l Weevil E r a d i c a t i o n Experiment (PBWEE) i n south M i s s i s s i p p i (43). In 1972 McKibben ( t h i s l a b o r a t o r y , unpublished data) develop ed 2 g e l formulations that were e f f e c t i v e i n the f i e l d f o r a t l e a s t 2 weeks and that compared f a v o r a b l y i n numbers of b o l l w e e v i l s captured w i t h 3 other formulations t e s t e d (44). The f i r s t contained a cottonseed o i l base to which humectants, a n t i f u n g a l agents, e m u l s i f y i n g agents, g e l l i n g agents, and d i l u e n t s were added. The second contained polyethylene g l y c o l 400, g e l l i n g agents, and d i l u e n t s . Both gels were dispensed i n t o paper cups and the tops were sealed by aluminum f o i l . Approximately 100,000 of these g e l s , prepared by a commercial packer, were used during l a t e 1972 and e a r l y 1973 i n the PBWEE (43). However, the lower cost and greater ease of s t o r i n g and handling PEGimpregnated c i g a r e t t e f i l t e r s mass-produced mechanically and enclosed i n a 1-dram v i a l caused them to be chosen f o r use through the remainder of the 1973 season. In 1974, s e v e r a l grandlure preparations were incorporated i n a 3-layer laminated p l a s t i c dispenser (HERC0N , H e r c u l i t e P r o t e c t i v e F a b r i c s Corp, Ν. Υ., Ν. Y . ) , that had proved e f f e c t i v e against the cabbage l o o p e r , T r i c h o p l u s i a n i (Hubner), and the gypsy moth, P o r t h e t r i a d i s p a r (L.) by Beroza et a l . (45). They were competitive w i t h , or more e f f e c t i v e than, the f o r m u l a t i o n of B u l l et a l . (44) throughout a 17-20 day p e r i o d i n 3 d i f f e r e n t t e s t s (46). P r e s e n t l y (1975), the H e r c u l i t e f o r m u l a t i o n , R


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formulations from s e v e r a l other p r i v a t e companies, and formulat i o n s prepared by USDA are being evaluated on the b a s i s of c o s t , ease o f storage and h a n d l i n g , s h e l f - l i f e , and l o n g e v i t y i n the field.


The Development Of B o l l Weevil Traps As the techniques f o r f o r m u l a t i n g grandlure improved, the designs of b o l l w e e v i l f i e l d traps d i d a l s o . A f t e r a v a r i e t y o f trap designs were t e s t e d beginning i n 1966, a wing t r a p coated w i t h Stikem and a P l e x i g l a s o b l i q u e funnel trap ( f o r l i v e w e e v i l capture) were s e l e c t e d f o r general use (17). Plywood wing traps p a i n t e d dark green and metal traps p a i n t e d y e l l o w (47) were used e x t e n s i v e l y i n l a r g e t e s t s i n Texas. Then paper wing traps were designed t o reduce the cost of t r a p p i n g programs; these and l a r g e r l i v e traps i n c o r p o r a t i n g the d a y l i g h t f l u o r e s c e n t y e l l o w c o l o r s (Saturn Yellow o r Solar Y e l l o w ) were found most a t t r a c t i v e to w e e v i l s (48). The Leggett trap was developed as a competitive n o n - s t i c k y trap that u t i l i z e d the behavior p a t t e r n s of the b o l l w e e v i l f o r most e f f i c i e n t capture (49). Although the d a y l i g h t f l u o r e s c e n t y e l l o w pigment alone i s a t t r a c t i v e to w e e v i l s , the proper d i s p l a y and handling of the pheromone i s necessary f o r an e f f e c t i v e t r a p p i n g system (42). A subsequent m o d i f i c a t i o n o f the Leggett trap has brought a d d i t i o n a l advantages. M i t c h e l l and Hardee (50) reduced the s i z e of t h i s trap and s t a t i o n e d i t c l o s e r to the ground and i n the cotton rows; l a t e r i n the season i t can be placed on the tops o f p l a n t s so as not to d i s t u r b c u l t i v a t i o n . These were described as i n - f i e l d traps and were found to aggregate both sexes i n e a r l y and l a t e season. A d d i t i o n a l l y , s i g n i f i cant numbers o f b o l l w e e v i l s , p r i m a r i l y females, were captured i n mid-season whereas previous traps had f a i l e d t o o b t a i n t h i s midseason response. C u r r e n t l y , the Leggett and i n - f i e l d traps a r e r e c e i v i n g the most extensive use. USDA and p r i v a t e companies are i n v e s t i g a t i n g m o d i f i c a t i o n s to lower the cost o f t h e i r production. ("Figure 8"). R

R

R

R e g i s t r a t i o n of Grandlure The Code of Federal R e g u l a t i o n s , T i t l e 40, Chapter 1, E n v i ronmental P r o t e c t i v e Agency, Subchapter E, P e s t i c i d e Programs, P a r t 162 provides r e g u l a t i o n s f o r the r e g i s t r a t i o n and c l a s s i f i c a t i o n o f p e s t i c i d e s as r e q u i r e d by the Federal I n s e c t i c i d e , F u n g i c i d e , and Rodenticide A c t . Under 1 6 2 . 3 ( f f ) * , a t t r a c t a n t s are defined as p e s t i c i d e s , i f they themselves are used d i r e c t l y to suppress pest p o p u l a t i o n s , and t h e r e f o r e when used as c o n t r o l agents are subject to the r e g i s t r a t i o n procedures of Part 162.6. The a p p l i c a t i o n f o r r e g i s t r a t i o n must c o n t a i n complete l a b e l i n g of p r i n t e d matter which i s to accompany the p e s t i c i d e , supporti n g data of e f f i c a c y without causing unreasonable adverse e f f e c t s on the environment, the complete formula, the manufacturing pro*Federal R e g i s t e r , J u l y 3, 1975.



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Figure 8.



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cess, and the proposed c l a s s i f i c a t i o n . The c r i t i c a l c o n s i d e r a t i o n s have to do w i t h whether the product i s hazardous based on the p h y s i c a l , chemical, and t o x i c o l o g i c a l p r o p e r t i e s of the product i t s e l f and the use to which the product i s put. Considerat i o n s of e f f i c a c y i n v o l v e the minimum e f f e c t i v e dosage and dosage range, a p p l i c a t i o n techniques, and c o m p a t a b i l i t i e s of the components of the formulated p e s t i c i d e . For outdoor t e r r e s t i a l uses, data must be obtained about movement i n the s o i l , s o i l p e r s i s t e n c e , l a b o r a t o r y s c a l e l e a c h i n g data on the parent p e s t i c i d e , and the s o i l degradation products, l a b o r a t o r y s c a l e r u n o f f data, and r a t e of h y d r o l y s i s . Henson e t a l . (unpublished d a t a ) , i n addressing these cons i d e r a t i o n s , found that 98% of the 4 components of grandlure was l o s t from s o i l and water w i t h i n 48 hours at constant temperatures of 21°C and 32°C. No evidence of the decomposition of a l c o h o l s I and I I was detected; the aldehydes undergo moderately f a s t o x i d a t i o n i n storage s o l u t i o n s , but no products of decompostion were found i n s o i l or water. The aldehyde and e s t e r o x i d a t i o n products of the pheromone aldehydes I I I and IV, 3,3-dimethylcyclohexanecarboxaldehyde and (E) and (_Z)-3,3-(dimethylcyclohexylidene)methyl formate, were completely v o l a t i l i z e d from s o i l w i t h i n 24 hours; more than 90% of (E) and ( Z ) - ( 3 , 3 - d i m e t h y l c y c l o h e x y l i d e n e ) a c e t i c a c i d remained a f t e r 24 hours. The f o l l o w i n g aspects of product hazard are to be considered: (1) human e f f e c t s i n c l u d i n g o r a l , dermal, i n h a l a t i o n , and o c u l a r , (2) sub-acute, c h r o n i c and delayed e f f e c t s , (3) s a f e t y data i n c l u d i n g d i a g n o s t i c and a n t i d o t a l i n f o r m a t i o n , and precautions necessary f o r r e e n t r y i n t o t r e a t e d areas. For the i n v e s t i g a t i o n of the p o t e n t i a l human hazards, grandlure was evaluated by seve r a l c r i t e r i a under c o n t r a c t w i t h Woodard Research C o r p o r a t i o n , Herndon, V i r g i n i a . Grandlure (the 4 components as an equal weight mixture) was found to have the f o l l o w i n g t o x i c o l o g i c a l p r o p e r t i e s : 1. O r a l LDt^Q i n mice i s i n excess of 600 mg/kg. 2. Dermal LD5Q i n r a b b i t s i s i n excess of 500 mg/kg. 3. Intravenous L D 5 0 i n mice i s 100 mg/kg. 4. I t i s a m i l d s k i n i r r i t a n t to r a b b i t s . 5. I t i s moderately i r r i t a t i n g to the eye of r a b b i t s , and a warning l a b e l i s i n d i c a t e d . 6. I f grandlure i s s y s t e m i c a l l y absorbed, t o x i c and pharmac o l o g i c a l s i g n s occur at l e v e l s w e l l below the l e t h a l l e v e l and should serve as adequate warning s i g n a l s i n d i c a t i n g overexposure. 7. The 96-hour LC5Q f o r b l u e g i l l s u n f i s h i s 44 ppm. A second product hazard, that of e f f e c t s on the environment, r e q u i r e s that data on the hazard to f i s h and w i l d l i f e i n c l u d i n g mammalian t o x i c i t y , acute and subacute a v i a n t o x i c i t y , acute aqua t i c organism t o x i c i t y , and subacute delayed or chronic e f f e c t s hazards be obtained. In c o n t r a c t w i t h the F i s h and W i l d l i f e S e r v i c e , U. S. Dept of the I n t e r i o r , the t o x i c i t y of grandlure was s t u d i e d i n m a l l a r d s and



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bobwhite q u a i l . Throughout the s t u d i e s , a t e c h n i c a l sample cont a i n i n g grandlure isomers I , I I , I I I , and IV i n the r a t i o of 30: 40:15:15 was used. Grandlure was found to have the f o l l o w i n g t o x i cological properties: 1. The 8-day d i e t a r y L C ^ Q f o r mallard ducklings i s greater than 5000 ppm. 2. The 8-day d i e t a r y L C ^ Q f o r bobwhite q u a i l chicks i s greater than 5000 ppm. 3. There were no m o r t a l i t i e s i n the f i v e groups of m a l l a r d c o n t r o l s o r i n the f i v e groups of bobwhite c o n t r o l s . 4. The concurrently determined 8-day L C 5 Q values f o r d i e l d r i n f o r m a l l a r d ducklings and bobwhite q u a i l chicks are 91.0 and 31.8 ppm, r e s p e c t i v e l y . On the b a s i s of the Woodard f i n d i n g s of 1972 and submission of a number of p h y s i c a l p r o p e r t i e s of the compounds, an e x p e r i mental permit was issued f o r l i m i t e d f i e l d s t u d i e s w i t h Grandlure i n 1973 and 1974. A f t e r r e c e i p t of the s o i l , water, and b i r d s t u d i e s and a d d i t i o n a l e f f i c a c y data obtained i n 1973 and 1974, the USDA-APHIS prepared an a p p l i c a t i o n f o r r e g i s t r a t i o n f o r grandl u r e f o r submission to the EPA. However, i t i s the p o l i c y of the USDA-APHIS that the government should not become the r e g i s t r a n t . Therefore, the p e t i t i o n has been re-submitted j o i n t l y by two p r i vate companies. Concurrently, the Zoecon Corporation i s completi n g a study sponsored by a grant from EPA to determine what i n f o r mation should be necessary f o r r e g i s t r a t i o n of "New-Generation" p e s t i c i d e s such as a t t r a c t a n t s and hormones. I t i s expected that the g u i d e l i n e s , Part 162.40, 162.63 - 162.82 of the Federal Code w i l l be r e v i s e d on the b a s i s o f t h i s r e p o r t . U t i l i z a t i o n Of Grandlure I n Integrated Insect E l i m i n a t i o n Programs The development of the b o l l w e e v i l pheromone has been part o f a broad research e f f o r t over the past 15 years t o develop a m u l t i d i s c i p l i n a r y technology w i t h which t o e l i m i n a t e the b o l l w e e v i l as an economic pest. From 1970 to 1974 a number of f i e l d t e s t s were c a r r i e d out i n c l u d i n g the South M i s s i s s i p p i P i l o t B o l l Weevil E r a d i c a t i o n Experiment (1971-1973). The l i t e r a t u r e on e a r l i e r f i e l d t e s t s (1962-1970) was reviewed by Hedin e t a l . (51). The 2-year P i l o t B o l l Weevil E r a d i c a t i o n Experiment (PBWEE) that began i n J u l y 1971, was the f u l f i l m e n t of plans made as long ago as 1958 by F e d e r a l , S t a t e , and i n d u s t r y researchers to develop technology capable of e l i m i n a t i n g the b o l l w e e v i l (E. P. L l o y d , BWRL unpublished data). I n 1969, a s i t e s e l e c t i o n subcommittee determined that southern M i s s i s s i p p i was the p o r t i o n of the country where i t would be most d i f f i c u l t to e l i m i n a t e the b o l l w e e v i l . The experiment was t h e r e f o r e planned f o r southern M i s s i s s i p p i and a d j o i n i n g areas i n L o u i s i a n a and Alabama. The c e n t r a l core ( e r a d i c a t i o n area) was encompassed by 3 b u f f e r zones. The purpose of the experiment was to determine whether i t was t e c h n i c a l l y and operat i o n a l l y f e a s i b l e to e l i m i n a t e a b o l l w e e v i l p o p u l a t i o n from an

American Chemical Society Library 1155 16th St. N. W. Beroza; Pest Management with Insect Sex Attractants Washington, D. C. Society: 20036Washington, DC, 1976. ACS Symposium Series; American Chemical


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ATTRACTANTS

i s o l a t e d area and to f u r t h e r develop suppression measures f o r use i n an o p e r a t i o n a l - s i z e d program. The suppression measures employed were as f o l l o w s : I. In-season c o n t r o l of the b o l l w e e v i l . II. Reproduction-diapause c o n t r o l of the b o l l w e e v i l i n l a t e summer and f a l l . III. Pheromone t r a p p i n g i n the s p r i n g w i t h : a. Grandlure b a i t e d t r a p s . b. Grandlure b a i t e d trap crops. IV. I n s e c t i c i d e treatment at the pinhead square stage of c o t t o n i n the s p r i n g . V. Release of s t e r i l e male b o l l w e e v i l s . During the f i r s t year of the P i l o t Experiment, two major problems were encountered that r e s u l t e d i n l a r g e r than a n t i c i p a t e d populations of b o l l weevils i n the s p r i n g of 1972. These were (1) an i n e f f e c t i v e volunteer in-season c o n t r o l program by growers i n 1971, and (2) p h y s i c a l o b s t r u c t i o n s that prevented thorough coverage w i t h i n s e c t i c i d e s a p p l i e d by a i r c r a f t . In 1972, these problems were corrected by in-season i n s e c t i c i d e treatments being supervised by program personnel and by supplemental a p p l i c a t i o n of i n s e c t i c i d e w i t h ground equipment. By mid-October 1972, w e e v i l s were not det e c t e d by f i e l d surveys or l a t e r by woods t r a s h examinations. In the s p r i n g of 1973, the capture of w e e v i l s i n b a i t e d traps i n d i c a t e d that a s u b s t a n t i a l number of b o l l w e e v i l s had immigrated i n t o the northern 1/3 of the core area that was presumed to be i s o l a t e d . However, the movement of the b o l l w e e v i l s i n t o t h i s area from i n f e s t e d c o t t o n l e s s than 10 miles d i s t a n t c l e a r l y showed that complete i s o l a t i o n d i d not e x i s t . During the l a s t month of the P i l o t Experiment (terminated August 10), 33 of a t o t a l of 236 cotton f i e l d s , a l l l o c a t e d i n the northern 1/3 of the e r a d i c a t i o n (core) area, received supplemental treatments w i t h i n s e c t i c i d e to e l i m i n a t e low l e v e l i n f e s t a t i o n s that were detected when cotton p l a n t s began f r u i t i n g . From s e v e r a l c r i t e r i a , i t was determined that the m a j o r i t y of these i n f e s t a t i o n s may have developed from eggs l a i d by p r e v i o u s l y mated female w e e v i l s that had migrated up to 25 miles from moderately i n f e s t e d c o t t o n . However, no i n f e s t a t i o n s were detected i n any of the 170 cotton f i e l d s l o c a t e d i n the lower 2/3 of the e r a d i c a t i o n area, those that were i s o l a t e d by 25 miles or more from i n f e s t e d cotton (E. P. L l o y d , BWRL unpublished data). Upon completion of the P i l o t Experiment, the T e c h n i c a l Guidance Committee f o r the P i l o t B o l l Weevil E r a d i c a t i o n Experiment concluded that " i t i s t e c h n i c a l l y and o p e r a t i o n a l l y f e a s i b l e to e l i m i n a t e the b o l l w e e v i l as an economic pest from the United S t a t e s " (52). The s p e c i f i c c o n t r i b u t i o n s of the b o l l w e e v i l pheromone to the PBWEE were as f o l l o w s : Grandlure-baited Leggett traps were placed around cotton f i e l d s during the f i r s t year from m i d - A p r i l u n t i l mid-July. They were b a i t e d twice weekly w i t h the prev i o u s l y described PEG c i g a r e t t e f i l t e r and Zoecon g e l f o r m u l a t i o n .



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During t h i s p e r i o d , 156,580 i n s e c t s were captured w i t h 5,418 t r a p s i n Zone 1 of the core area and 132,350 w i t h 5,979 traps i n Zone 2. Although the t r a p s were not able t o c o n t r o l the p o p u l a t i o n b u i l d - u p , they served i n v i t a l d e t e c t i o n . Grandlure was a l s o employed a t b a i t s t a t i o n s i n trap crops, e a r l y cotton p l a n t i n g s , four rows wide, w i t h 3 b a i t s t a t i o n s , that were side-dressed w i t h a systemic i n s e c t i c i d e , a l d i c a r b . Scott e t a l . (53) found that n e a r l y a l l the emerging overwintered b o l l w e e v i l s moved i n t o the trap crops and were k i l l e d before squaring (buds) i n the normal p l a n t i n g s . Then, as squaring began i n the normal p l a n t i n g s , the trap crops l o s t t h e i r a t t r a c t i v e n e s s t o l a t e r emerg ing i n s e c t s . The pheromone traps ( b a i t s t a t i o n s ) improved the performance of the trap crop over unbaited trap crops. In September 1972, t r a p p i n g was resumed a f t e r c o t t o n s t a l k d e s t r u c t i o n . During the f a l l , 559 w e e v i l s were trapped from 110 traps i n Zone 1 of the core area and 1875 i n s e c t s from 602 traps i n Zone 2. While these numbers may appear low, t h i s t r a p p i n g oc curred a f t e r a r i g o r o u s reproduction-diapause i n s e c t i c i d e spray program that was designed t o (and succeeded) sharply reduce the i n s e c t p o p u l a t i o n that would otherwise enter diapause. The r o l e of the traps i n t h i s phase was t o assess the success o f t h i s con t r o l phase. In 1973, Leggett traps were placed around a l l c o t t o n f i e l d s i n Zones 1 and 2 a t the r a t e o f 1 t r a p / a c r e . The grandlure formu l a t i o n used as b a i t contained 3 mg of grandlure i n PEG impregnated f i l t e r s that were placed i n a v i a l (44). With the improved f o r m u l a t i o n , traps were r e b a i t e d only weekly. From A p r i l 16 t o August 3, 1973, 1436 w e e v i l s were captured i n the core area and 40,173 w e e v i l s (100 per trap) i n the b u f f e r areas. Only 28 w e e v i l s were c o l l e c t e d i n the e r a d i c a t i o n (core) area from May u n t i l August 1973, a l l but one i n the northern h a l f o f the e r a d i c a t i o n area (the south h a l f i n c l u d e d 80% of the t o t a l acreage). Grandlure-baited trap crops were a l s o used i n 1973; r e s u l t s were s i m i l a r t o those obtained i n 1972 (E. P. L l o y d , BWRL, unpublished data). Since the PBWEE, a l e s s extensive p o p u l a t i o n suppression pro gram has beem c a r r i e d out i n Arkansas. I n 1974, i n - f i e l d traps (pheromone) p l u s i n s e c t i c i d e s prevented r e p r o d u c t i o n o f emerging over-wintered w e e v i l s from June 13 t o J u l y 6. I n - f i e l d t r a p s alone captured 76% of the emerging w e e v i l s from p l a n t i n g time t o pin-head squares and 95-96% from J u l y 6 to J u l y 31. Clumping o f eggs (a number found i n a s m a l l area) by females was obvious and prevented the traps alone from being more e f f e c t i v e i n c a p t u r i n g females emerging w i t h i n the clumps (Ε. B. M i t c h e l l , BWRL, unpub l i s h e d data). The Farm B i l l f o r 1973 d i r e c t s the Secretary o f A g r i c u l t u r e t o undertake a b e l t w i d e b o l l w e e v i l e r a d i c a t i o n program. A concep t u a l p l a n f o r a beltwide program was developed by a committee o f s c i e n t i s t s under the auspices o f the N a t i o n a l Cotton C o u n c i l . How ever, t h i s p l a n was not endorsed by the USDA. I n October 1974,



50


the State A g r i c u l t u r a l Experiment S t a t i o n D i r e c t o r s , the Commissioners o f A g r i c u l t u r e and the Heads of the Entomology Departments of the Land Grand U n i v e r s i t i e s of the i n v o l v e d S t a t e s , o f f i c i a l s of the USDA, and r e p r e s e n t a t i v e s of the cotton indust r y unanimously agreed that a beltwide e r a d i c a t i o n program should be preceded by an e r a d i c a t i o n t r i a l on roughly 100,000 acres. This t r i a l i f s u c c e s s f u l might l e a d d i r e c t l y t o a beltwide program. Funds f o r the t r i a l program have not yet been requested by the A d m i n i s t r a t i o n nor appropriateD. On the other hand, the Extension S e r v i c e has requested a d d i t i o n a l funds f o r managing b o l l w e e v i l populations. Abstract In 1969, four terpenoid compounds were demonstrated by identification and s y n t h e s i s t o comprise the boll w e e v i l pheromone. Since then the pheromone has been utilized s u c c e s s f u l l y f o r monit o r i n g and p o p u l a t i o n r e d u c t i o n and has been a component in s e v e r a l i n t e g r a t e d pest management and e l i m i n a t i o n programs. I n the course of these tests, it was necessary t o develop a l o n g - l a s t i n g formulation, to determine the best r a t i o of components, t o improve the methods of syntheses t o reduce c o s t s , t o commence registration w i t h EPA, and t o develop efficient traps and t r a p p i n g procedures. The pheromone was effectively utilized i n the recent South Mississippi t e s t s t o monitor and reduce the i n s e c t p o p u l a t i o n . Plans for f u t u r e t e s t s are discussed. Recent s t u d i e s showed that gut m i c r o f l o r a , d e f i c i e n t diets, and sterilization decrease pheromone biosynthesis. Disclaimer The use o f trade or p r o p r i e t a r y names does not n e c e s s a r i l y imply the endorsement o f these products by the U. S. Department of A g r i c u l t u r e .

Literature Cited 1. Hunter, W. D., Hinds, W. E., USDA Bull. No. 51, (1905) 116 pp. 2. Townsend, C. H. T., Insect Life (1895) 7, 295-309. 3. Howard, L. O., Bull. Entomol. Circ. 18 Second Series, Revision of 14 (1896) 8 pp. 4. Malley, F. W., Texas Farm Proc. (1900) 3, 183. 5. Sanderson, E. D., Soc. Prom. Agric. Sci. Proc. (1904) 25, 157-70. 6. Hunter, W. D., USDAFarmersBull. No. 180 (1904) 31 pp. 7. Howard, L. O. USDA Bur. Entomol. Rep. (1918) 24 pp. 8. Isley, D., Arkansas Agric. Exp. Stn. Bull No. 496 (1950) 42 pp. 9. Walker, R. L., Fife, L. D., Bondy, F. F. J. Econ. Entomol. (1949) 42, 685-6.


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Hedin, P. Α., Thompson, A. C., Gueldner, R. C., Minyard, J. P. J. Insect Physiol. (1972) 18, 79-86. Minyard, J. P., Tumlinson, J. Η., Thompson, A. C., Hedin, P. A. J. Agric. Food Chem. (1967) 15, 517-24. Hedin, P. Α., Rollins, C. S., Thompson, A. C., Gueldner, R. C. J. Econ. Entomol. (1975), In press. Brand, J. Μ., Markovetz, A. J. Bracke, J. W., Wood,D.L., Amer. Chem. Soc. 168th National Mtg. Pest. Chem. Div., Atlantic City, Sept. 1974. Klassen, W., Earle, N. W., J. Econ. Entomol. (1970) 63, 11958. Davich, T. B., Keller, J. C., Mitchell, Ε. B., Huddleston, P., Hill, R., Lindquist, D. Α., McKibben, G., Cross, W. H. J. Econ. Entomol. (1965) 58, 127-31. Hardee, D. D., McKibben, G. H., Rummel, D. R. Huddleston, P. M., Coppedge, J. R. Environmental Entomol. (1974) 3, 135-8. McKibben, G. H., Hardee, D. D., Gueldner, R. C., Hedin, P. A. J. Econ. Entomol. (1971) 64, 317-9. Hardee, D. D., McKibben, G. Η., Gueldner, R. C., Mitchell, Ε. B., Tumlinson, J. Η., Cross, W. H. J. Econ. Entomol. (1972) 65. 97-100. Hardee, D. D., Graves, Τ. Μ., McKibben, G. H., Johnson, W. L . , Gueldner, R. C., Olson, C. M. J. Econ. Entomol. (1974) 67, 44-6. Bull, D. L . , Coppedge, J. R., Ridgway, R. L . , Hardee,D.D. Graves, T. M. Environ. Entomol. (1973) 2, 829-35. Beroza, M., Paszek, E. C., Mitchell, E. R., Bierl, Β. Α., McLaughlin, J. R., Chambers, D. L . , Environ. Entomol. (1974) 3, 926-8. Hardee, D. D., McKibben, G. Η., Huddleston, P. Μ., J. Econ. Entomol. (1975) In Press. Hardee, D. D., Lindig, O. Η., Davich, T. B., J. Econ. Entomol. (1971) 64, 928-33. Cross, W. H., Leggett, J. E. Hardee, D. D. U.S. Dep. Agric. Coop. Econ. Ins. Rep. (1971) 21, 367-8. Leggett, J. E . , Cross, W. H., Agric. Coop. Econ. Ins. Rep. (1971) 21, 773-4. Mitchell, Ε. Β., Hardee, D. D., J. Econ. Entomol. (1974) 67, 506-8. Hedin, P. Α., Thompson, A. C., Gueldner, R. C. Toxicol. Environ. Chem. Res. (1973) 1, 291-351. Knipling, E. F., Proc. Boll Weevil Conf. II: Feb. 14-15, 1974, Memphis, Tn. (In Press). Scott, W. P., Lloyd, E. P., Bryson, J. O., Davich, T. B. J. Econ. Entomol. (1974) 67, 281-3.


Utilization of the Boll Weevil Pheromone for Insect Control - ACS

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