Palmer, D.F.Schenk, T.C.Chiang, H.C.2012-11-202012-11-201985https://hdl.handle.net/11299/13952931 pagesSince its introduction and subsequent colonization in the northeastern United States, the European corn borer (ECB), Ostrinia nubilalis (Hubner), has invaded all of the major corn-growing areas on the eastern half of the continent and has shown a phenomenal adaptation to regional climatic and environmental conditions. The insect has dispersed west to the Rockies, south to the Gulf States, and north into southern Canada. With adaptation to regional conditions, ecotypes of the ECB have developed the ability to produce increasing numbers of generations per year throughout its range in North America. When the ECB came to this continent it produced one to two generations per year; it now produces up to four generations per year in southern areas. Over the years, voltinism of the borer has changed in some locations, has differed from location to location, and has varied in the same locale from year to year. These changes, which are due to adaptation to different regional climatic conditions, have resulted in the wide distribution of the insect population. This regional adaptation has often produced heterovoltinism in transition zones.en-US