2004 Variant Western Corn
Rootworm On-Farm Survey

Since the early 1990's the amount of damage in first year corn (after soybeans) has been spreading northwestward from its focal point around Piper City in Ford County. The variant western corn rootworm now lays eggs in soybean fields as a result of intense selection pressure due to extensive use of the corn/soybean rotation as a corn rootworm management option. In 2002, 2003, and 2004 a survey was conducted in first year corn fields to document the management and spread of the variant western corn rootworm. Each year the survey examined five roots from each of ten first-year corn fields within each county. The use of soil insecticide, seed treatment, or transgenic hybrid was not determined for any of the fields surveyed. The roots were then rated using the Iowa State 1-6 Rating Scale. Information on how the Iowa State root rating scale works, monitoring for wcr in soybean fields using sticky traps, or effectiveness of rootworm control products in the University of Illinois efficacy trial, please use the links provided.

Some things to look at on the 2004 map:

In 2004, counties outside of the known problem area were surveyed. The amount of injury found has spread to areas in western Illinois and northwestern Illinois from 2003 to 2004. Although we are seeing a fair amount of injury, in some areas it is still not exceeding the economic injury level. Scouting is still recommended in these areas using the yellow sticky traps.

Lodged corn Scouting

The shaded area of Illinois was not surveyed in 2004 due to the known presence of the variant western corn rootworm. Average Root Rating Per County 1.0-1.9 2.0-2.9

Useful Links:
Iowa State Root Rating Scale
Scouting (Adobe PDF)
Rootworm Control Products

Click here to view county comparison chart.

For more information feel free to contact:
Jared B. Schroeder Crop Sciences Department S-327 Turner Hall, MC-046 1102 S. Goodwin Ave. Urbana, IL 61801 (217) 244-2687 jbschroe@uiuc.edu		Susan T. Ratcliffe Crop Sciences Department S-316 Turner Hall, MC-046 1102 S. Goodwin Ave. Urbana, IL 61801 (217) 333-9656 sratclif@uiuc.edu

This survey could not have been possible without the help of several people. We would like to include a very sincere thank you to each of the following people:

Sean Evans, Bill Lindenmeier, Marion Shier, Russel Higgins, Dale Baird, Bill Brink, Jim Morrison, Pete Fandel, Mike Roegge, Dave Feltes, Dennis Bowman, Nate Edlefson, Matt Starr, Steve Nightingale, Our own IPM Team, and Martin Bohn's Crew

To see results from 2003 please click here.