The black cutworm does not overwinter in Iowa, however adults migrate here on southwesterly winds in early spring. Potentially significant numbers of adults were first documented on April 27 and 28 this year across most of the southern two-thirds of Iowa. A second notable flight occurred on May 5 and 6; that flight was recorded throughout the state.
Iowa State University
Hodgson, Erin W. and Tollefson, Jon J., "2009 Predicted Black Cutworm Cutting Dates in Corn" (2009). Integrated Crop Management News. 650.