Northern corn rootworm larvae occasionally damage fields of first-year corn in Iowa. Rootworms typically have a 1-year life cycle and rotating corn with another crop has been a very successful management strategy to prevent lodging and yield loss from this insect. Unfortunately, some populations of the northern corn rootworm have successfully adapted to the corn-soybean rotation and now have a 2-year life cycle. This 2-year life cycle is called extended diapause because some of the eggs remain dormant in the soil for nearly 2 years before the larvae hatch. For instance, for the eggs that are laid in 1999, some larvae hatch in 2000, but the remainder will not hatch until 2001.
Iowa State University
Rice, Marlin E. and Tollefson, Jon J., "Corn rootworms and lodged first-year corn" (1999). Integrated Crop Management News. 2149.
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