160 



taminatlon of the weevils during the rearing process. Results of our tests 

 showed that more pheromone was always isolated from the frass of uncontaminated 

 weevils, by a factor of 1.2-300. The results were significant at the 1% level 

 of probability (P=0.01). The quality of weevils that are contaminated with 

 bacteria is therefore reduced from that of normal weevils insofar as pheromone 

 production is concerned. 



307. ; Thompson, A. C; Hardee, D. D.; and Hedin, P. A. 1970. Consti- 

 tuents of the cotton bud. XIX. Attractancy to the boll weevil of the 

 terpenoids and related plant constituents. J. Econ. Entomol. 63: 

 1819-1821. ; • 



Bioassay results with 37 terpenoids/and related plant constituents indicate 

 that linolool oxide, geranyl acetate, neryl acetate, rose oxide, fenchone, 

 menthone, isovaleraldehyde, and llnalool were among the most attractive 

 to Anthonomus grand i s Boheman. Three 4-6 component mixtures were nearly 

 as attractive as extracts of cotton buds. 



308. , and Wiygul, G. 1978. Rhythms in pheromone production of the male 

 boll weevil. Science 199: 954-986. 



Male boll weevils, Anthonomus grandis . held in a light regimen of 16 hours of 

 light and 8 hours of darkness released pheromone rhythmically during the 24 

 hours. The amount released during peaks was typically 20 times the amount 

 released in valleys. The ratio of the two alcohol components of the phero- 

 mone also showed a daily rhythm. Under continuous light, both the release 

 of pheromone and the ratio of the two alcohol components were arrhythmic. 

 In darkness, pheromone release was diminished more than tenfold over the 

 20-day test period. 



