Thirty sites reporting this week. European corn borer (ECB)-E was trapped at twelve sites with a high count of 21 at the Hurley site in Ulster County and ECB-Z was trapped at six sites. Corn earworm (CEW) was trapped at sixteen sites, with ten sites high enough to be on a 4, 5, or 6 day spray schedule (see chart below). Fall armyworm (FAW) was trapped at thirteen sites and Western Bean cutworm (WBC) was trapped at twenty-four sites this week.

This week we saw a real increase in WBC numbers. Degree day accumulations for most sites indicate that we should be close to 25-50% WBC moth emergence according to data from the University of Nebraska. WBC is a pest of both corn and dry beans. In corn, it is important to scout late whorl and early tassel corn for WBC egg masses (see last week’s post).

In dry beans, the WBC eggs are often inconspicuous, larvae feed only at night and spend the day in the soil. As a result, scouting for pest activity is very difficult.  Keep track of the pheromone trap counts in your area to determine peak moth flight, which indicates when peak egg laying takes place. Pod feeding typically occurs 10-20 days after peak moth flight.  If possible, scout adjacent field corn or sweet corn fields to help gauge the potential risk in a dry beans.

Percent WBC moth emergence, data from
University of Nebraska