Western bean cutworm moth captures have increased in some areas of northern Illinois and producers are encouraged to scout fields for this pest and be ready to apply a rescue treatment if needed. University of Illinois Extension is monitoring a pheromone moth trapping network for this pest in many northern Illinois counties.

Historically, the western bean cutworm has been a pest in the western Corn Belt, but over the last few years it has moved eastward. The pest was first detected in Illinois in 2004 in Warren County. Unlike cutworms, the western bean cutworm is a late-season pest of corn feeding mainly on the ears, predisposing them to disease infections.

In corn, the female moth lays their eggs on the upper surfaces of leaves. After hatching, the larvae pass through five instars and feed on host plants for about 30 days. Newly hatched larvae move from the leaves to the corn whorls to feed on the tassels and then to the silks. As the larvae and corn ears develop, the larvae begin feeding on ear tips, affecting both yield and quality. An ear may be infested by more than one larva, and this feeding can cause economic damage.

In Illinois, the western bean cutworm has been more commonly found in northwestern and north-central counties. A fact sheet on the western bean cutworm, including the biology, life cycle, and management, can be found at this University of Illinois web site: http://ipm.illinois.edu/fieldcrops/insects/western_bean_cutworm/index.html