Early-season corn caterpillars

Abstract

<p>Seedling corn is attacked each spring by a variety of caterpillars. Identification is the first step in integrated pest management in determining if there is a potential problem from insects. This article discusses how to identify caterpillars most likely to be found in Iowa corn and the injury they cause to seedling plants. Black cutworms less than 0.5 inch in length feed on leaves, whereas larger larvae can cut or drill plants. Almost all cutworm damage to corn is caused by this caterpillar. Cutting can occur below the surface when soil is dry, or above ground when soil is wet and tight around the plant. Cutting rarely occurs after the fifth true-leaf stage but cutworms may drill into the side of larger stalks. The black cutworm does not overwinter in Iowa. Eggs are laid in the spring when adults fly into Iowa from southern states.</p>