On March 20, we confirmed the first black cutworm moth trapped in Muscatine County, Iowa. Since then, several counties have also reported captures. Adults were trapped in Lucas County (30 March), Des Moines County (30 March), Marion County (29 March), and Story County (31 March). We use these captures to start estimating growing degree days for predicted cutting dates in corn. Normally predicted cutting dates happen in mid-May, but they may be slightly earlier this year. Look for our 2012 predicted cutting dates later this month.
Black cutworm larvae typically damage corn, but can also feed on soybean. Certain fields may be at a higher risk for black cutworm damage than others; low lying and poorly drained, next to areas of natural vegetation, weedy, and other characteristics should be scouted first.
Cutworms are normally noctural feeders and curl up with disturbed. Look for wilted, dead or missing plants. Top photo by Steph Marlay, bottom photo by Tracy Cameron.