Sterility and longevity of adult range caterpillars (Lepidoptera: Saturniidae) reared from irradiated field-collected pupae

Studies were conducted from 1976 through 1979 to evaluate the potential for use of the sterile insect technique as a management strategy for the range caterpillar, Hemileuca oliviae Cockerell. Nonirradiated females mated with males exposed as pupae to 50 krad gamma radiation produced eggs with 97.8-99.4% sterility. Females exposed as pupae to dosages ranging from 20 to 60 krad produced eggs with 96-100% sterility when mated with nonirradiated males. A preliminary study in 1979 on competitiveness of irradiated males indicated some mating advantage for normal males. These data indicate that sterility levels acceptable for field control uses could be achieved. If economical mass-rearing techniques could be developed to produce pupae of uniform age and normal males do not have too much of an advantage in mating, irradiation could be an important tool in managing this pest.