Sterilization of the navel orangeworm, Paramyelois transitella (Walker), by gamma radiation (Lepidoptera: Phycitidae)

The effects of gamma radiation were tested on all stages of the navel orangeworm. Mature, eight-day-old pupae were the best able to tolerate dosages sufficient to make all individuals completely sterile. The effective dosage, established at 50,000 rads ± 3.5 per cent, did not affect mating, egg-laying, or longevity of the moths. Treatment with 40,000 rads reduced fertility drastically but did not give complete sterility. Treatment with 80,000 rads reduced the mating capacities of both sexes, and the treated females laid very few eggs. There was no evident difference between the sexes in the sterilizing dosage.