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ARS Home » Research » Publications at this Location » Publication #75262
Title: INUNDATIVE RELEASE OF ARCHYTAS MARMORATUS (DIPTERA: TACHINIDAE) AGAINST THECORN EARWORM AND FALL ARMYWORM (LEPIDOPTERA: NOCTUIDAE) IN WHORL-STAGE CORN

Author
item Proshold, Fredrick
item GROSS, HARRY - DECEASED
item Carpenter, James

Submitted to: Journal of Entomological Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: The fall armyworm and corn earworm are the two most destructive insect pests of corn in the southeastern United States. Populations of corn earworms build up on corn and subsequently move into cotton, peanuts, soybeans, and vegetables costing millions of dollars annually in loss or control. This study showed that inundative releases of a native parasitoid, Archytas marmoratus, effectively increased the natural parasitism of corn earworm and fall armyworm larvae in whorl-stage corn. The release of laboratory reared Archytas marmoratus in conjunction with other management strategies may well reduce the usage of environmentally harmful pesticides for the control of these two pests.

Technical Abstract: A 3-yr pilot test was conducted to determine the feasibility of controlling early season populations of corn earworm, Helicoverpa zea (Boddie), and fall armyworm, Spodoptera frugiperda (J. E. Smith) by augmentative releases of the tachinid parasitoid Archytas marmoratus (Townsend). 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 (#1500 per ha per week). Fall armyworm larvae were parasitized at a much lower rate than corn earworm larvae. In a contiguous corn growing area, there was a positive correlation between density of corn earworm larvae and percentage parasitism within 0.8 km of the release field. The field with the greatest density and percentage parasitism of corn earworm larvae was the one farthest from the release site, indicating good host finding capability by A. marmoratus. These results show that inundative releases of this parasitoid could become an important component of integrated management strategies against early season populations of corn earworms and fall armyworms. The high percentage of superparasitism in corn earworm larvae suggests that the release rate of A. marmoratus will need to be adjusted to host larval density.