Seasonal Abundance of the European Corn Borer Ostrinia nubilalis (Hbn.) Within the North Central United States

Annual changes in corn borer populations in the North Central States were measured as a phase of a Regional Project, NC-20, entitled Factors Influencing Corn Borer Populations in Minnesota, Iowa, Kansas, Nebraska, Missouri and Ohio over a period of years. Standardized procedures were followed to estimate the seasonal abundance of the European corn borer, Ostrinia nubilalis (Hbn.), under cropping procedures in different locations within the North Central States. The primary purpose of the present bulletin is to present results for the 1965 to 1969 period and to compare these results with the previous 10 years and thus attempt to analyze in a gross way certain aspects of the population changes for the entire 15-year period. In 1964, measurements of borer populations were discontinued in two counties, Jefferson in Kansas and Van Wert in Ohio. Therefore, the present bulletin will be concerned only with six counties with long-term records from the four states of Iowa, Minnesota, Missouri and Nebraska