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207 



information about the purpose of these unique compounds. 



401. ; Thompson, A. C; Gueldner, R. C; and Hedin, P. A. 1975. Effect 

 of a systemic juvenile hormone peptide analog on the developing boll 

 weevil (Coleoptera: Curculionidae) . J. Miss. Acad. Sci. XX: 40-41. 



A systemic JHA could be extremely effective against the boll weevil, Anthonomus 

 grandis Boheman, since the entire immature life of this insect is spent encased 

 in the fruit of its host plant. Therefore, the boll weevil larva would not 

 only feed on the JHA, but would also be in constant physical contact with the 

 material. We conducted experiments to determine the concentrations of ethyl 

 pivaloyl-L-alanyl-£-aminobenzoate required to alter development in immature 

 boll weevils. The peptide was synthesized in our laboratory. The addition 

 of 50 ppm of the peptide to the diet of the boll weevil larvae was sufficient 

 to cause about 50% reduction in normal adult emergence; concentrations of 150, 

 200, and 250 ppm reduced normal adult emergence to less than 10%. Most in- 

 sects reached the pupal stage successfully. Hov/ever, after pupation, the 

 development of treated insects seemed to halt, and the majority, especially 

 at concentrations above 50 ppm, remained as live pupae for an extended period, 

 but never molted to adults. 



402. ; Vinson, S. B.; and Barfield, C. S. 1977. Ovipositional behavior 

 of Bracon mellitor Say, a parasitoid of the boll weevil ( Anthonomus 

 grandis Boheman) . III. Isolation and identification of natural 

 releasers of ovipositor probing. J. Chem. Ecol. 3: 151-158. 



The chemical cues in the frass of larvae of the boll weevil, Anthonomus grandis 

 Boheman, that elicit an ovipositional response in females of Bracon mellitor 

 Say were isolated by a combination of column, thin-layer, and gas-liquid 

 chromatography. Derivatization, analytical tests, and mass spectrometry were 

 used to identify the biologically active materials as long-chain fatty acid 



