At least one of the mysteries of caterpillars in soybean has been solved. Loopers were reported from several fields across the state during mid- to late June, but the exact species of looper was not known. I collected pupae (cocoons) from soybean in Marshall County on June 22. On June 30 and July 1, cabbage looper adults emerged. Thus, the cabbage looper was causing some of the problems, although it is still possible that additional species of loopers may have defoliated soybean in other counties.
Iowa State University
Rice, Marlin E., "Cabbage loopers emerge from soybean" (2001). Integrated Crop Management News. 1881.
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