2003 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 and 2003, a survey was conducted in first year corn fields to document the management and spread of the variant western corn rootworm. The 36 county survey examined five roots from each of ten fields within each county. 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 soil insecticides in the University of Illinois efficacy trial, please use the links provided.

Some things to look at on the 2003 map:

In this area scouting or management is advised		Beyond this line to the northwest there is limited implementation of western corn rootworm management options (i.e. transgenics or soil insecticides) resulting in greater root injury
		In east central Illinois we are assuming that a soil insecticide or transgenic is being used resulting in lower root injury.
Average Root Rating Per County 1.0-1.9 2.0-2.9 3.0-3.9		Lodged corn

Click here to use the interactive County Map

Click here to view a comparison
of the 2002 and 2003 Mean Root Ratings per County

Click here to view a map showing the Distribution of
Western Corn Rootworm Adults in Illinois Soybean Fields, 2002 and 2003.
Courtesy of Joe Spencer, Center for Economic Entomology, Illinois Natural History Survey

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

Acknowledgments