The true armyworm migrates into North Dakota from the south. Multiple moth flights were seen in early June and they are now mature two-inch-long caterpillars. The NDSU Extension Crop and Pest Report says larvae feeding has been seen on corn leaves in Grand Forks County. Large numbers of true armyworms have been captured in pheromone traps in northwest Minnesota. South Dakota State University Extension also reports larvae feeding in winter wheat and other small grains. Rye cover crops have been a common denominator for these infestations.
