True Armyworm Caterpillars Observed in South Dakota Wheat

Dark green and tan curled caterpillars with an orange stripe along their sides.
Figure 1. True armyworm caterpillars can vary in color. Courtesy: Adam Varenhorst

Written with contributions by Shelby Pritchard, former SDSU Extension Pest Management Specialist.

Originally Submitted: July 22, 2022

Wheat harvest is underway in South Dakota, and one of our seemingly annual pests has been observed in wheat fields. While scouting last week, we observed small populations of true armyworms in wheat in Northeastern South Dakota. Although the populations weren’t large enough to cause immediate action, it is an important reminder to continue scouting wheat up to harvest.

True armyworms will not only defoliate wheat, but they can also clip heads when the plant is maturing. For more information regarding true armyworm scouting and management please refer to our previous article (True Armyworm Caterpillars Spotted in South Dakota). If management is necessary, choose an insecticide with a pre-harvest interval that won’t greatly delay harvest.

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