Thirty-three sites reported this week. European corn borer (ECB)- E was caught at six sites and ECB-Z was caught at four sites. The hybrid ECB was caught at the Hurley (4) site. Twenty-three sites reported corn earworm (CEW) catches this week with eighteen sites high enough to be on a 4, 5, or 6 day spray schedule (see table at bottom of post). Fall armyworm (FAW) was only caught at twelve sites and Western bean cutworm (WBC) was caught at twenty-six sites.

NEWA Western bean cutworm flight emergence lookup table.

According to the table above, most sites are near 20-25% flight emergence for WBC and should therefore be scouting for eggs with a 4% threshold for processing sweet corn and a 1% threshold for fresh market sweet corn. WBC will usually lay eggs on the upper side of the top 1-3 leaves of pre-tassel corn, close to the leaf base. After tasseling has finished WBC seek out younger corn or dry beans. WBC will most likely peak within the next two weeks.

Average sweet corn trap catches for all reporting sites from 5.31.22 –7.26.22.

Interactive Sweet Corn Pheromone Trapping Network Map

Dry Bean Western Bean Cutworm Alert
7.26.22

This year we are monitoring 12 WBC traps placed next to dry bean fields. Dry bean growers should scout adjacent corn for WBC eggs and larvae when cumulative trap catch reaches 50 moths. So far three sites, Churchville, LeRoy, and Penfield have reached 50 cumulative moths. Peak WBC flight historically occurs the first week of August. All dry bean growers should begin scouting pods for WBC feeding about 10 days after peak flight regardless of cumulative trap catch, and should continue to scout for three weeks, especially if damage has been seen in recent years.

Check 10 random spots in a field, 5 plants per spot. Inspect all the pods on the plants looking for holes. Surface feeding can be caused by other insects. WBC will mine directly into the pod and will often feed on the seed inside. European corn borer will also feed inside the pod and would most likely still be present. If there is damage going directly into the pod and seed but no larva present, it is quite possibly WBC. During the day WBC larva are not actively feeding in the pod, instead they drop to the soil and will remain there until night. Fresh damage will be green, not brown.

This project is funded by the NYS Dry Bean Industry.