Effect of Seedling Injury by the Stalk Borer (Lepidoptera: Noctuidae) on Regrowth and Yield of Corn1

Abstract

The regrowth capabilities of corn seedlings after injury by natural infestations of larvae of Papaipema nebris at growth (leaf) stages 2–8 were determined in a 3-year study. Yield losses resulting from injury by larvae were due to both the reduction in the number of plants producing ears and the reduction in grain weight per ear. In general, seedlings injured earlier in development produced fewer harvest able ears (grain weight > 30 g/ear at 15.5% moisture) and less grain than plants injured later in development. Injured plants tended to sucker (tiller) more than uninjured plants. Of the injured plants that did not set harvest able ears, 58.1% survived to harvest time. These nonproductive plants probably competed with the uninjured plants for sunlight, moisture, and soil nutrients until harvest. New damage was not observed in plants beyond the 8-leaf stage. Damage to corn in plots adjacent to field margins containing stalk borer-infested grasses varied by row, with the row immediately bordering the field margin generally sustaining the most damage.