Case Details
European Corn Borer Adults and Generation
Submitted by Greg L. Andrews on 7/25/2001
During July 23-25 in Western Pierce County, very high numbers of adult moths have been observed and in sweeps in 3rd Crop Alfalfa fields adjacent to field corn. On the average (at noon) 2-3 per sweep were captured in the sweep net during potato leafhopper checks. There were very large numbers within 50-100 feet of corn. No egg masses were observed under leaves of the corn. Some specimens showed some abdominal swelling indicating egg laying soon to come.
Observations of adult moths in these numbers are 2-3 weeks ahead of normal here. Does this give us any indication of the risk potential similar to losses we observed in Western Wisconsin in 1996? Growers are asking.
Reply by Bryan M. Jensen on 7/27/2001
These are not European corn borer moths. However, it is difficult to tell exactly what species it is. Probably one of the webworms (sod webworm, alfalfa webworm). They are very close in appearance to European corn borers. A quick and dirty way to differentiate webworm adults from European corn borer is that webworms tend to fold their wings around their body when at rest, corn borers will keep their wings on a near hoizontal plane. A good website for picture of European corn borer is located at Iowa State http://www.ent.iastate.edu/imagegallery/
