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192 



chromatographic column. The activity could not be found in any single frac- 

 tion, but returned on recombination of two of the fractions. Thus, we were 

 faced with elucidation of a multicomponent mixture. Considerable removal of 

 nonactive components was achieved by chromatographing the two active frac- 

 tions on silica gel silver nitrate columns and then bioassaying appropriate 

 fractions in combination until activity was demonstrated again. Gas chroma- 

 tography was then used to separate the two alcohol components which could not 

 be separated by column chromatography. Now we knew of three separate compo- 

 nents which had to be present for activity. Later, on an open tubular column, 

 we were able to separate the cis an' trans forms of the aldehyde, at which 

 time we realized that four components were required. 



373. . 1976. Seasonal variations in the emission of volatiles by cotton 

 plants growing in the field. Environ. Entomol. 5: 1234-1238. 



The volatiles emitted by growing cotton, Cossypium sp. in the open field 

 were collected daily during June to September 1957 by pulling an air stream 

 through a porous polymer and then desorption with pentane. From analysis 

 by GLC and GLC-MS, a total of 70 compounds was identified, only 15 of which 

 were also found in cotton bud essential oil. The amount of total volatiles 

 collected reached a maximum in late July and early August when the cotton 

 plant squaring and flowering was highest. Then production decreased, to some 

 degree with continued fruit set and more rapidly with approaching senescence. 

 Although the sex pheromone of the boll weevil is a more powerful attrac- 

 tant than the plant for this Insect, the plant may play some role in its 

 migration. 



374. . 1976. Using a sex attractant for insect control. Am. Chem. Soc, 

 CHEMTECK 6 (July): 444-459. 



The problem is the interaction of the boll weevil with the cotton plant - a 



y 



