E race European corn borer (ECB) numbers remain low this week; Z race counts are up at a few locations.  Corn earworm (CEW) numbers took a big jump at several locations this week, with numbers at some locations high enough to call for a 4 day spray schedule while temperatures are above 80 (See table below).  The weather forecast calls for lower temperatures later this week, so a day can be added to the spray interval once temperatures drop for a few days.  Fall armyworm numbers remain low.  Western bean cutworm (WBC) numbers are mostly lower this week with the exception of Kennedy in Chautauqua county.  WBC larvae were found last week in field corn in the Attica area, so where CEW numbers are not high enough to determine the spray schedule, scout for ECB and WBC egg masses and larvae in late whorl and tassel-emergence stage fields.  Here’s a video from Purdue on scouting for WBC egg masses and larvae.  Ontario is suggesting a threshold for WBC of 5% infested plants in sweet corn.  If WBC is not present, the 15% infested plants at tassel emergence and 5% at silking thresholds are still useful.

Trap catches for the week of 8/7-14/12