88 



squares. The biological assay method employed in this study may be used by 

 plant physiologists in studying the physiological and biochemical changes that 

 occur during the abscission process. 



163. Cobb, P. P., and Bass, M. h. 1968. Some effects of photoperiod, tempera- 

 ture, and food on the induction of diapause in the boll weevil. J. Econ. 

 Entomol. 61: 62A-625. 



Newly emerged adult Anthonomus grandis Boheman collected from squares during 

 mid-June to mid-August, were subjected in groups of AO to various co.f.binations 

 of food, temperature, and photoperiod. Exposure to each of these factors 

 individually resulted in no evidence of diapause. However, certain combinations 

 did result in diapause in studies where photoperiod, temperature, and food varia- 

 tions were interacted. Generally, the greatest incidence of diapause and fat 

 content occurred in those groups subjected to a 10-hour, 80"? photoperiod, a 

 14-hour, 50"? dark phase, and fed squares or bolls. Diapause in males seemed 

 to exceed that in females in all groups with a 10-hour photoperiod and a constant 

 80°F temperature. The occurrence of diapause increased in groups with an 80-50"? 

 temperature combination. Less fat accumulation was observed in groups fed 

 laboratory medium. 



164. Coker, R. R. 1976. Economic impact of the boll weevil. L[L Boll Weevil 

 Suppression, Management and Elimination Technology. Proceedings of a 

 Conference, February . 13-15, 1974, Memphis, Tenn. U.S. Agric. Res. Serv. 

 [Rep.] ARS-S-71, pp. 3-4. 



Crop losses and control costs alone range from $200 million to $300 million 

 every year. More insecticides are applied for boll weevil control than for 

 control of any other crop insect. More than $21 million in Federal, State, 

 and cotton Industry funds have been spent exclusively for boll weevil research 

 since the BWRL was put into operation in 1961. This is a sizable, 



