Western bean cutworm adults have begun emerging in Iowa this year, particularly in the southwest and southeast. Corn fields in the late whorl stage are most attractive to egg-laying females, with damage becoming evident in August and early September. University of Nebraska has developed a degree day model for 50 percent adult emergence. This year, 50 percent emergence of western bean cutworm moths in southern and central Iowa was approximately July 21. So now is the time to start scouting for egg masses before larvae enter developing corn ears.
Iowa State University
Hodgson, Erin W., "Use Treatment Thresholds for Western Bean Cutworm" (2008). Integrated Crop Management News. 575.
The Iowa State University Digital Repository provides access to Integrated Crop Management News for historical purposes only. Users are hereby notified that the content may be inaccurate, out of date, incomplete and/or may not meet the needs and requirements of the user. Users should make their own assessment of the information and whether it is suitable for their intended purpose. For current information on integrated crop management from Iowa State University Extension and Outreach, please visit https://crops.extension.iastate.edu/.