By Michael Hillstrom, Forest Health Specialist, Fitchburg; Michael.Hillstrom@wisconsin.gov

Caterpillars wandering the snow in February? Yes, the “winter cutworm,” Noctua pronuba, is a hardy species that is sometimes observed active in temperatures as low as the 20s.

Winter cutworms navigate the fresh snow that fell on Feb. 15, 2024. / Photo Credit: Wisconsin DNR

If you see hundreds, or even thousands, of caterpillars out in the snow, it’s likely this species. Like other cutworms, winter cutworms are plump and earth-toned. Winter cutworms can be identified by pairs of black dashes bordered by white on their upper sides. The moths of this species are known as the “large yellow underwing.”

Although winter cutworms feed on a wide variety of crops, vegetables and grasses, they rarely rise to the level of pest — unlike other cutworm species. Even better, during a recent sighting in central Wisconsin, they provided the local birds with a snow-day feast.