Integrated Crop Management is published by the Department of Entomology , Iowa State University , Ames, Iowa. Stalk borer is a pest to corn and occasionally soybeans. Damage is usually limited to the first few rows adjacent to grassy fencerows, terrace backslopes, and road ditches, but occasionally the damage is fieldwide.
Stalk borers have one generation per year.
Moths are attracted to leaves and stems of grasses and broadleaf weeds, starting in late August through mid-October. The eggs overwinter and hatch the following spring starting when around 500 base-41 degree days has accumulated. These larvae feed in the spring growth of the grasses, but eventually grow too large to stay inside the small grass stems, forcing them to move to larger plants. This movement from grassy areas begins by 1,400 base-41 degree days, with about 10 percent of the larvae moving by 1,400 degree days and 50 percent by 1,700 degree days. Early stage stalk borer has a purple midsection and an orange head with a black stripe.