|Pikul Jr, Joseph|
Submitted to: Corn Rootworm Areawide Management Program
Publication Type: Abstract Only
Publication Acceptance Date: April 3, 2001
Publication Date: N/A
Technical Abstract: Crop rotation is a good defense against corn rootworm feeding damage because eggs laid in summer usually hatch the next spring to larvae needing corn to survive. Rotation is not always practiced, however, and some northern and western corn rootworm populations have adapted to survive 2-year rotations by, respectively, extending the egg stage for a second winter and by laying eggs in crops grown in rotation with corn. These adaptations may further increase pesticide applications for rootworms, which already account for nearly 20% of the insecticide applied to U.S. field crops. Better ways are needed to detect the existence and spread of these adaptations and to monitor rootworms where insecticides are now routinely applied without knowledge of pest populations. The widespread prophylactic use of soil insecticides has undoubtedly developed from difficulties associated with monitoring rootworm populations, especially the larval populations which are primarily responsible for crop damage. Standard larval monitoring techniques are tedious because they usually involve the handling of large soil volumes to sample the subterranean habitat. An easier approach is to sample just the root system, but the validity of this approach for estimating larval populations must still be verified. Here, we report results from 1999 and 2000 tests that compared larval recovery from corn root systems with cumulative adult emergence data. Sampling was done on research plots that permitted measurements to be made in relation to crop rotation and soil nitrogen levels.