Technical Abstract: A generic phytosanitary irradiation (PI) dose of 350 Gy is proposed for all Lepidoptera on all commodities. The measure of efficacy for this dose is prevention of egg hatch when late pupae are irradiated. Although the literature was thoroughly examined for relevant studies only those that could reasonably satisfy criteria of acceptable irradiation and evaluation methodology, proper age of pupae, and adequate presentation of raw data were accepted. Because eggs and larvae of insects are more radiosusceptible than pupae 350 Gy would be efficacious against all immature Lepidoptera. The recommendation is based on studies with 33 species in nine families. This dose will fill a major gap in the generic dose of 400 Gy for all Insecta except pupae and adult Lepidoptera that the USDA-Animal and Plant Health Inspection service has approved for commerce and would provide a valuable generic PI treatment for international acceptance through the International Plant Protection Convention.