Never have European corn borer populations been this low. Surveys conducted in Minnesota and Wisconsin this past fall indicate that the numbers of live larvae in corn stalks are at historical lows in these two states. The Minnesota population appears to be in a tie with population levels seen in 1974 and 1985. However, Bt corn was not available during those years. When Bt corn acres in Minnesota are considered, the European corn borer population density will drop to a lower level on a statewide per-acre basis than is shown in the graph. The Wisconsin population is at the lowest level ever! Although I haven't shown it on the graph, information from Wisconsin dates back to the first European corn borer survey in 1942. The 1998 Wisconsin population was even lower than that in Minnesota.
Iowa State University
Rice, Marlin E., "Corn borers should increase in 1999" (1999). Integrated Crop Management News. 2157.
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