Adult northern corn rootworms have been extremely abundant in soybeans this August (see image of beetles on corn silk, below). Beetle populations in soybeans at the extension field lab in Boone County averaged 45 per 20 sweeps; however, Brad Buchanan, crop consultant in Cedar Rapids, reports 50--150 per 20 sweeps in some eastern Iowa fields. Their abundance has prompted many questions regarding what they are doing in soybeans and if they will present a threat to rotated corn next year. Here are several of the questions we have encountered, and our responses to those questions.
Iowa State University
Rice, Marlin E. and Tollefson, Jon J., "Northern corn rootworms in soybeans: What does it mean?" (2005). Integrated Crop Management News. 1456.
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