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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #91872
Title: SURVIVAL OF ARCHYTAS MARMORATUS (DIPTERA: TACHINIDAE) IN DIAPAUSE AND NONDIAPAUSING STRAINS OF HELICOVERPA ZEA (LEPIDOPTERA: NOCTUIDAE).

Author
item PROSHOLD, F. - RETIRED (USDA-ARS)
item Carpenter, James

Submitted to: Journal of Entomological Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: The corn earworm is a devastating pest of corn, cotton and many other crops important to American agriculture. Currently, most control tactics for this pest have relied exclusively on the use of pesticides. Efforts to increase the use of integrated pest management (IPM) in our agricultural systems have revealed the need to better understand the role of natural enemies such as parasitoids in reducing pest populations. Recent studies of the parasitoid Archytas marmoratus indicated that augmentative releases of this parasitoid could dramatically reduce corn earworm populations. In the study reported here, we found that this parasitoid is unable to overwinter in the cooler regions of its range. Therefore, control of the corn earworm by this parasitoid would require augmentative releases or recolonization of the parasitoid annually. We also found that the physiology of the overwintering corn earworm does not affect the development of the parasitoid.

Technical Abstract: Archytas marmoratus (Townsend) was reared on four strains of corn earworm, Helicoverpa zea (Boddie). One strain did not diapause or entered a weak diapause. A portion of the other three strains entered diapause when reared at 19 or 22 C and 10:14 h photoperiod (L:D). No A. marmoratus entered diapause; 90% eclosed with no differences among strains or rearing condition, and the number of days from host pupation to eclosion within rearing condition was similar regardless of host strain. Parasitized pupae did not enter a chill-terminated diapause, as indicated by loss of larval eyespots within two weeks. Either the presence of A. marmoratus maggots prevented diapause in its host or diapause was terminated by rapid development of the maggot after host pupation. These data suggest that A. marmoratus does not overwinter as a larva or pupa in the cooler regions of its distribution.