There are variants of both corn rootworm species in Iowa that are resistant to crop rotation. The northern corn rootworm overcame the annual rotation of corn with another crop by developing a two-year life cycle. This variety of the northern corn rootworm (known as extended diapause) became common and caused extensive damage to rotated corn in the late 1980s in northwest Iowa. Since then it has spread throughout Iowa and is probably found in every county.
Iowa State University
Prasifka, Patricia L.; Tollefson, Jon J.; and Rice, Marlin E., "Rotation-resistant corn rootworms in Iowa" (2006). Integrated Crop Management News. 1333.
The Iowa State University Digital Repository provides access to Integrated Crop Management News for historical purposes only. Users are hereby notified that the content may be inaccurate, out of date, incomplete and/or may not meet the needs and requirements of the user. Users should make their own assessment of the information and whether it is suitable for their intended purpose. For current information on integrated crop management from Iowa State University Extension and Outreach, please visit https://crops.extension.iastate.edu/.