No. 17 Article 4/July 21, 2006

Annual Corn Rootworm "Digs" Have Begun

This past week, we began our root digs at the Orr Research and Demonstration Center, located near Perry, as well as in Urbana. The experiment near Perry represents an expansion westward of our Insect Management and Insecticide Evaluation program, managed by Ron Estes, Department of Crop Sciences, University of Illinois. As the variant western corn rootworm extends its range throughout much of the state, we want to make sure that we challenge this insect pest with the latest root-protection tools in sites that are as locally relevant to producers as possible. It seems certain that this evaluation program will become more established in southern Illinois as the variant western corn rootworm pushes in this direction. After we finish our root evaluations in Urbana this week, we will concentrate our efforts in DeKalb and Monmouth for the week beginning July 24.

Based on the lack of corn rootworm larvae that are floating to the surface in our root-soaking tanks, we believe the root-feeding period is over for much of central Illinois. By next week, maximum root injury will likely have occurred across northern Illinois as well. So far, the level of root injury has been very severe in our Urbana experiments. This intense pressure is anticipated because of our use the preceding year of a trap crop system (late-planted corn grown with pumpkins). However, even in our first-year corn plots (soybeans in 2005), the level of root damage has been extreme this season.


Severe corn rootworm larval injury in Urbana experiment (untreated check).

For those interested in taking a look at corn rootworm product performance in previous years (2004 and 2005), we encourage you to review the reports, which are available on-line.

We look forward to sharing the results from our 2006 experiments in the Bulletin later this season. We welcome your reports and observations from around the state regarding product performance issues you may have encountered.--Mike Gray

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