Eggs ofPlodia interpunctella(Hübner) were irradiated at different ages to determine the production and inheritance pattern of genetic damage and to assess the possible use of P1or F1adults for release in a sterile-insect release for population control. P1fertility and the numbers of F1adults were greatly decreased by 4-krad but not by 1- or 2-krad exposures to gamma irradiation. However, 2 krad was the highest dose that allowed an adequate percentage of the irradiated eggs (22.6%) to complete development to the adult. All combinations of age and dose that produced progeny (F1) were tested, and F1progeny were almost fully fertile and produced normal numbers of F2progeny. Irradiation of eggs for mass production of either sterile or partially sterile adults was found not to be feasible.