Recent trap monitoring has confirmed that western bean cutworm, a destructive insect that can cause severe yield loss in cornfields, has moved further eastward and has continued to spread into northern areas of Indiana.

The heaviest infestations are being reported in unprotected cornfields across northern Indiana, specifically in many northwestern Indiana counties, with some reports extending into Illinois and Ohio.

Spraying is occurring as signs of increased populations surface, but spraying must take place before the insect moves into the ear where it is protected by the husk. With moth flights nearly complete, increased feeding can be expected.

Young western bean cutworm larvae feed on tassels and silks, but eventually tunnel through the silk channel to reach the developing kernels. Direct yield loss occurs as larvae consume all or parts of developing kernels.

Because of the labor-intensive nature of scouting, the critical timing needed for insecticide applications and the possibility that multiple treatments may be necessary, insecticides may not be an economical or effective solution to the western bean cutworm problem.

Fields planted with in-plant control of western bean cutworm with the Herculex I and Herculex XTRA insect protection traits have shown to effectively protect against western bean cutworm.

Purdue University entomologists John Obermeyer and Christian Krupke discuss the problem further.