Integration of inherited sterility and a parasitoid, Archytas marmoratus (Diptera: Tachinidae), for managing Helicoverpa zea (Lepidoptera: Noctuidae): acceptability and suitability of hosts

One of the factors important to the successful integration of inherited sterility and biological control is the suitability of hosts from irradiated parents. In this study corn earworm, Helicoverpa zea (Boddie), larvae from irradiated parents were compared with larvae from normal parents as to their acceptance by and suitability for Archytas marmoratus (Townsend). Normal larvae and larvae from crosses of irradiated males with normal females were placed in whorl-stage corn and subsequently exposed to maggots of A. marmoratus. Host and parasitoid emergence was approximately equal from both the normal and the irradiation treatment; however, parasitism was greater in the normal hosts. In field-cage studies in which adult A. marmoratus were released and allowed to larviposit, percentage parasitism and emergence of H. zea and A. marmoratus were equal between the normal treatment and the irradiation treatment. When maggots were applied to caged plants, emergence of H. zea and A. marmoratus were both low. Significantly more H. zea emerged in the normal treatment than in the irradiation treatment and the application of maggots did not affect emergence of H. zea. There were no significant differences in emergence of A. marmoratus between the normal and irradiation treatments. In a concurrent laboratory study, emergence of H. zea did not differ between normal and irradiation treatment but was greatly reduced when exposed to maggots. Similarly, emergence of A. marmoratus was not affected by irradiation treatment. Larvae from a cross of irradiated males and normal females appear to be both acceptable and suitable for development and subsequent emergence of A. marmoratus