POTENTIAL OF THE COMBINED USE OF INHERITED STERILITY AND A PARASITOID, ARCHYTAS-MARMORATUS (DIPTERA, TACHINIDAE), FOR MANAGING HELICOVERPA-ZEA (LEPIDOPTERA, NOCTUIDAE)

The potential for combining inherited sterility with Archytas marmorat us (Townsend) (Diptera: Tachinidae) to manage the corn earworm, Helico verpa zea (Boddie) (Lepidoptera: Noctuidae), was examined in the labor atory and in the field. Larvae from crosses of irradiated males with n ormal females, irradiated females with normal males, and normal males with normal females were exposed to maggots of A. marmoratus in the la boratory and the field. Emergence of parasitoids from larvae of irradi ated female and normal male crosses was significantly less than that o f larvae from normal parents and of larvae from irradiated male and no rmal female crosses, but there were no differences between emergence f rom larvae from normal crosses and irradiated male by normal female cr osses. Mortality of unparasitized larvae was greater when male or fema le parents were irradiated, than when they were unirradiated. Larvae o f irradiated parents developed more slowly than did larvae of normal p arents; at the time of collection from the field, larvae resulting fro m irradiated male by normal female crosses were predominantly fourth a nd early fifth instars, while larvae resulting from normal male by nor mal female crosses were predominantly late fifth instars. Among larvae resulting from normal crosses, parasitoid emergence was greater from hosts collected as fifth instars than from hosts collected as fourth a nd early fifth instars. Combining inherited sterility and A. marmoratu s may be feasible for managing the early season population of H. zea.