European corn borer trap catches continue to be on a downward trend, but are still being caught at most locations.  Corn earworm are being caught at most trapping locations and increased significantly at a couple of sites this week.  Fall armyworm are being caught at more locations but numbers are still low.  Western bean cutworm were caught in low numbers at most locations, and the flight appears to have peaked.

More locations have corn earworm catches high enough to determine the spray schedule (see chart below) this week, which will also take care of the other worm pests.  Where CEW is not high enough to drive the spray schedule, scout tassel emergence and silk stage fields for western bean cutworm and European corn borer egg masses and small larvae (see links at right for photos of egg masses and larvae).   Where western bean cutworm are being found, a threshold of 1% infested plants is being recommended in Michigan.  If WBC is not being found, use the regular thresholds of 15% infested plants in tassel emergence stage fields, and 5% in silk stage fields.

Recommended spray intervals based on corn earworm trap catches