|LINGREN, PETER - USDA-ARS (RETIRED)
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/2002
Publication Date: N/A
Interpretive Summary: The corn earworm is a serious pest of corn and cotton. Moths can migrate several hundred kilometers (a kilometer is approximately 6/10 of a mile) in one night to cause potentially damaging economic infestations in susceptible host plants. Previous migration studies examined large-scale weather patterns, 72-hour wind patterns, and citrus pollen on moths to identify the source of these migrants. However, retention of citrus pollen for 72 hours by corn earworm moths had not been examined previously. In this study, 15 to 100 percent of corn earworm moths collected at 72 hours after removal from citrus blooms were marked with citrus pollen. The validation of estimated moth flights will lead to more accurate determinations of corn earworm source areas. These findings will impact the timing and location of control measures that support areawide pest management of corn earworms in subtropical and temperate crop production regions.
Technical Abstract: In previous migration studies, the presence of citrus pollen on adult Helicoverpa zea (Boddie), in conjunction with synoptic weather systems and 72-h backtrack trajectories were used to identify source zones of migrants. However, data is lacking regarding retention of citrus pollen by H. zea adults through 72 h. We exposed laboratory-reared and feral H. zea adults to citrus blooms for a 12-h period in laboratory and field studies and examined insects for the external presence of citrus pollen (i.e., marking) at 12-h intervals through 72 h. Citrus pollen marking was higher for females than males at the time of removal from citrus blooms. Fifteen to 100 percent of H. zea adults were marked with citrus pollen at 72 h after removal from citrus blooms. Pollen loads ranged from rare (less than or equal to 10 pollen grains) to moderate (101 to 500 grains) during 1995; only rare and light (11 to 100 grains) pollen loads were detected during 1996. Citrus pollen marking of H. zea adults through 72 h after removal from citrus blooms has not been previously documented. This data provides evidence of H. zea utilizing available blooming citrus groves in the absence of the host crop and will impact current perspectives regarding H. zea and host plant interactions and timing of pest management techniques.