INUNDATIVE RELEASE OF ARCHYTAS-MARMORATUS (DIPTERA, TACHINIDAE) AGAINST THE CORN-EARWORM AND FALL ARMYWORM (LEPIDOPTERA, NOCTUIDAE) IN WHORL-STAGE CORN

A 3-yr pilot test was conducted to determine the feasibility of contro lling early-season populations of corn earworm, Helicoverpa tea (Boddi e), and fall armyworm, Spodoptera frugiperda (J. E. Smith), by augment ative releases of the tachinid parasitoid Archytas marmoratus (Townsen d). Percentage parasitism of corn earworm larvae was increased to 42% in non-isolated fields of whorl-stage corn and >90% in isolated fields by inundative releases (approximate to 1500 A. marmoratus female fema le per ha per week). Fall armyworm larvae were parasitized at a much l ower level than corn earworm larvae. In a contiguous corn growing area , there was a positive correlation between density of corn earworm lar vae and percentage parasitism within 0.8 km of the release field. The field with the greatest larval density and percentage parasitism of co rn earworm larvae was the one farthest from the release site, indicati ng good host finding capability by A. marmoratus. These results show t hat inundative releases of this parasitoid could become an important c omponent of integrated management strategies against early-season popu lations of corn earworm and fall armyworm. The high percentage of supe rparasitism in corn earworm larvae suggests that the release rate of A . marmoratus will need to be adjusted to host larval density.