A study on sterility of irradiated Carposina nipponensis Wals.
In studies in China, pupae of Carposina niponensis Wlsm. 4-10 days old collected in the field in Xinzheng County, Henan, were exposed to a dose of 10-50 kRγ-radiation. Mortality reached 87.5-97.5% among pupae 4-6 days old exposed to 30-40 kR, but exposure to 10-40 kR had no significant effect on adult emergence, survival and mating rate of moths to which pupae exposed to radiation when 8-10 days old gave rise; the females exposed to 20-40 kR laid averages of 75.8-82.3 eggs each, of which 4.2-47.3 hatched. Exposure to 50 kR reduced oviposition to an average of 65.5 eggs/female and the hatching rate to 2.2%, and reduced the mating rate. The optimum dose was considered to be 20-40 kR and the optimum time for exposure 8-10 days after the formation of the pupa.