CHAMPAIGN, Ill. High corn prices are leading many growers to plant corn every year and to overuse pesticides and other bug-killing technology to maximize yields, researchers report. In many instances, pesticides are applied without scouting fields to see if they are needed, violating a bedrock principle of integrated pest management. The result is a biological diversity desert in many corn and soybean fields in the agricultural Midwest, and signs that the surviving insects are becoming resistant to several key bug-fighting tools now available to farmers.
University of Illinois crop sciences professor Michael Gray and his colleagues conducted a survey of corn and soybean pests in 47 counties in Illinois from late July to early August in 2011, and found densities of some key insect pests to be at zero or near zero in many counties.
"I've never seen anything like it in 22 years of doing this kind of research," Gray said. "From an insect diversity perspective, it's a biological desert in many of those fields." Even western corn rootworm adults (which normally lay their eggs in cornfields in late summer) were difficult to find in many counties, he said.
In part, these low numbers are the result of environmental conditions particularly wet springs the past few years, Gray said. However, the widespread use of Bt-corn hybrids, which produce one or more insecticidal proteins, and the common practice of broadcasting mixes of insecticide and fungicide on corn and soybean fields also plays a role, he said.
And yet, when Gray asks farmers at growers' meetings if they plan to use Bt corn again this year, a huge majority says yes.
"Many producers indicate that in order to have access to high yielding germplasm, the use of Bt hybrids is essential," Gray said. "It is likely that many growers also will use a soil insecticide at pla
|Contact: Diana Yates|
University of Illinois at Urbana-Champaign