University of Illinois

No. 12/June 13, 1997

Slow Going for European Corn Borers

European corn borer activity thus far in Illinois has been most notable by its absence. Several observers have reported finding moths in "action sites" near cornfields, but only one individual has related a significant moth flight. A grower in Grundy County told me that he drove through a "blizzard" of moths around 9:30 p.m. on June 9. However, his report of large numbers of corn borer moths is the only one I'm aware of. Either corn borer populations are much reduced this spring, or the moths have yet to take flight in some areas because of the cool temperatures. As Rick Weinzierl, Extension entomologist on campus, has indicated, the moths often will not fly on cool nights. So maybe the moths are lying in the weeds (so to speak), waiting for more optimal temperatures. We'll alert you to any report of significant moth captures.

Despite the lack of corn borer activity, you still need to scout cornfields for their presence. Maria Venditti, my graduate student who has been working with corn borers since 1995, and her "team" scouted four study fields (Bt-corn was planted in two of them) on June 10 and found a total of two egg masses. The corn in the field was 18 inches tall. Again, either corn borer populations are suppressed, or egg-laying activity is just under way. Time will tell, so stay alert.

Kevin Steffey, Extension Entomology, (217)333-6652