|DE CAMELO, LEONARDO - WA STATE UNIVERSITY
|ZACK, RICHARD - WA STATE UNIVERSITY
|SMITHHISLER, CONNIE - Retired ARS Employee
Submitted to: Journal of British Columbia Entomological Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2011
Publication Date: 12/30/2011
Citation: De Camelo, L.A., Adams, T.B., Landolt, P.J., Zack, R.S., Smithhisler, C. 2011. Seasonal patterns of capture of Helicoverpa zea (Boddie) and Heliothis phloxiphaga (Grote and Robinson)(Lepidoptera: Noctuidae) in pheromone traps in Washington State. Journal of British Columbia Entomological Society. 108:3-10.
Interpretive Summary: The corn earworm moth is a pest of numerous crops. A sex pheromone is used in traps to determine its presence and abundance so that pesticides and other pest management methods can be used most efficiently. However, growers may also capture large numbers of a related non-pest moth, Heliothis phloxiphaga, in the same traps, leading to errors and unnecessary pesticide sprays. Researchers at the USDA-ARS laboratory in Wapato, Washington, in collaboration with scientists at Washington State University, Pullman, WA used sex pheromones of the two moths, and a feeding attractant, to determine the seasonal abundances of the two species in intensive agricultural areas of south central Washington. They determined that the corn earworm moth begins to fly about 6 weeks later than H. phloxiphaga in the spring, and flies about 6 weeks later in the autumn. This information will help growers understand when to be concerned about discriminating between these two moths in their monitoring traps.
Technical Abstract: In each of the 6 years of this study in south central Washington state, male corn earworm moths, Helicoverpa zea (Boddie), first appeared in pheromone traps in late May to early June, and were present continuously until mid to late October. Maximum numbers of corn earworm moths captured in pheromone traps were generally from early/mid August into late August or early September. A smaller peak of corn earworm moth activity was sometimes evident in late June/early July. Male Heliothis phloxiphaga (Grote and Robinson) moths first appeared in pheromone traps in April, and were generally present throughout the season until mid to late September. Two peaks of numbers of H. phloxiphaga males in pheromone traps for each year of the study indicate two generations per season; with one flight of moths mainly in June and the other mainly in August. Numbers of corn earworm moths in floral lure traps were 1 to 3 % of the numbers captured in pheromone traps, but included many females. Numbers of H. phloxiphaga moths captured in floral lure traps were 5 to 16% of the numbers captured in pheromone traps. Corn earworm moths trapped with the floral lure included females, with a sex ratio of 1 females to 1.3 males.