Thirty-three sites reported this week with only three sites reporting European corn borer (ECB)-E. ECB-Z was caught at six sites. Fifteen sites reported corn earworm (CEW) with eleven high enough to be on a 4, 5 or 6 day spray interval (see table at bottom of post). Fall armyworm (FAW) moths were caught at three sites and Western bean cutworm (WBC) was caught again at the Williamson site this week. The hybrid ECB moth was caught only at the Hurley site.

WBC flight has started. Emergence is forecast to be at 25% when 1319 degree days (base 50°F) have accumulated beginning on May 1st (see table below). The degree day accumulation (May 1st, base 50°F) for sweet corn trap network sites ranges from 682-977. Peak flight in NY usually occurs during the first week of August.

Percent WBC moth emergence, data from
University of Nebraska

FAW is beginning to increase. When scouting sweet corn for FAW look for egg masses on the leaves. Egg masses consist of 50-150 eggs and can be distinguished from ECB by the fine hairs covering the egg mass. Feeding damage is also very different from ECB. FAW will cause ragged feeding damage on leaves with large amounts of frass below the feeding site. The larva has a distinct inverted ‘Y’ on the front of the head. To help with identification of the different larvae please see the <a href=”http://hdl.handle.net/1813/57328″>Sweet Corn Larval Pest Identification</a> fact sheet.