Here or Coming? Western Bean Cutworm
Ellen Phillips, Extension Educator – Crop Systems, Countryside
Extension Center, 708-352-0109, email@example.com
Previously a western Corn Belt pest, the Western Bean Cutworm
made its presence known in western Illinois this past summer.
A monitoring trap set out for one night caught enough moths for
scientists to ask the questions, “How long have they been
here?” and “Where else are they?”
Despite its name, the Western Bean Cutworm is not only a pest
on dry beans but also a late season problem on corn. Feeding on
corn ears, it chews and scars the kernels opening up pathways
for other pathogens like mold.
Western Bean Cutworms only have one generation a year. The moths
emerge in early July. In corn, females lay their egg masses (about
50 eggs) on the upper surfaces of the leaves. Larvae will hatch
and begin feeding in 5-7 days and continue feeding for about a
month. Due to the mobility of the larva, one egg mass can affect
plants in a ten foot diameter around the plant. Once the larva
has completed its fifth instar stage, it burrows into the soil
where it overwinters in the prepupal state.
Because of the mobility of this pest, scouting and timing of
insecticide treatments are critical. To learn more go to www.ipm.uiuc.edu
or check out the following websites.
Cutworm, in Corn and Dry Beans, University of Nebraska –
Pests of North America
Bean Cutworm: Characteristics and Management in Corn and Dry Beans,
Colorado State University