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315 



virus remained viable when it was added to the feeding stimulant bait used to 

 infect weevils with protozoan pathogens in the field, and weevils feeding on 

 the formulation became infected when it had been exposed 1-J days in nature. 



612. , and Sikorowski, P. P. 1978. Observations of boll weevil midgut 

 when fed natural food or on bacterially contaminated artificial diet. 

 J. Invertebr. Pathol. 32: 64-70. 



Boll weevils fed natural food had normal midgut morphology, but weevils fed 

 bacterially contaminated artificial diet had deteriorated midguts which became 

 progressively less functional with continued feeding on the diet. Reversal of 

 the conditions occurred when the weevils were returned to natural food. This 

 recovery did not take place, however, if the deterioration was too advanced. 

 All strains of boll weevils had similar midgut responses. Cellular destruction 

 in the midgut and loss of tissue function led to typical symptoms of starvation 

 and desiccation during the first 10 days of adult life. Continued feeding upon 

 contaminated food resulted in premature death. These observations show the im- 

 portance of sanitation in mass-rearing procedures. It also may provide an ex- 

 planation for subnormal boll weevil quality as reported by other authors who 

 measured longevity, pheromone, and fatty acid production. 



613. Mangum, C. L.; Earle, N. W.; and Newsora, L. D. 1968. Photoperiodic 

 induction of diapause in the boll wetivil, Anthonomus grandis . Ann. 

 Entomol. Soc Am. 61: 1125-1128. 



It was determined that diapause in adult Anthonomus grandis Boheman, could 

 be induced by exposing eggs to 11-br daily periods of white light and by 

 holding subsequent stages in darkness. Adults responded to different photo- 

 periods only if the immature stages were held in darkness. Infrared irradia- 

 tion had no effect on diapause. Preliminary studies were made of the action 

 spectrun for induction of diapause. Effects of brief interruptions in the 



