Populations of western corn rootworm beetles were lower in Ohio soybean fields in 2001 than in 2000, according to a recent Ohio State University extension survey.
Bruce Eisley, an Ohio State extension entomologist, says western corn rootworms trapped in soybean fields have been decreasing since the survey started in 1998.
With these beetles, yield loss may occur when trap catches are at two beetles per trap per day or higher. Extension personnel monitored traps in 76 fields in 19 counties in central and western Ohio from mid-July to late August. Average beetle counts were less than 0.20 beetles per trap per day in 75% of the fields compared to 70% of fields in last year's survey. The largest beetle count in the survey in 2001 was 0.72 beetles per trap per day.
“Based on these counts, first-year corn rootworm does not appear to be a problem in Ohio at this time,” says Eisley.