Over the next several weeks, non-Bt cornfields should be scouted for European corn borers. If populations do exceed the economic threshold, treatment is warranted to prevent substantial yield loss. Scouting should start in the tallest cornfields because adults (moths) are often attracted to these fields in larger numbers. Look for shot holes in the leaves after corn reaches 17 to 21 inches in extended leaf height. When shot holes or larvae are found in the taller corn, scout fields with smaller corn. There is very little reason to scout a field for larvae if no shot holes are detected in the leaves.
Iowa State University
Rice, Marlin E., "Scouting first-generation European corn borers" (2001). Integrated Crop Management News. 1904.
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