2005 Year in Review

No Glyphosate Resistance Yet Found In Illinois

Source: Julie Toohill at (309) 663-7692

Even though university researchers have identified a probable glyphosate-resistant Palmer pigweed case at specific sites in Georgia-one that they are calling a "difficult to control" case until it is confirmed through genetic testing-Illinois soybean farmers can rest assured that their checkoff investment is investigating weed control and resistance, and so far, no weeds in the state have been found to be glyphosate resistant.

"As with this case in Georgia, once again, weeds have shown their ability to adapt their sensitivity to Roundup Ready systems," said Bryan Young, weed science associate professor, Southern Illinois University (SIU). "What we are seeing is that weed control with glyphosate is not as effective as it once was."

It is widely agreed among soybean farmers and researchers that glyphosate is the single most effective herbicide for use in soybean fields. Some of the most challenging decisions in glyphosate-resistant soybean management entail the number of glyphosate applications necessary for season-long weed control and what rate or formulation of glyphosate is best.

Weed scientists from the University of Illinois (UI), Southern Illinois University (SIU), and Western Illinois University (WIU) are working together in a coordinated Illinois soybean checkoff-funded project to study weed challenges and to look at the effects of herbicide applications and management practices on weed control in Illinois soybean fields.

"Research has been and will continue to be vital to the soybean checkoff," explained Ken Dalenberg, Illinois Soybean Association Research Chairman from Mansfield. "The checkoff-funded area that focuses on weeds is a good area for investment. It looks at new and existing problem weeds and how to manage or eliminate them. It also looks at alternative ways to manage the weeds we have. Given the recent case in Georgia, we are ahead of the curve looking for and studying herbicide resistance."

SIU researchers say that, in general, herbicides used in conventional soybeans still provide effective weed control in many situations, but their performance has been reduced dramatically with the development and spread of herbicide-resistant weeds in Illinois. Weed management in conventional soybeans generally requires the integration of two or more herbicides applied as a soil residual preemergence, followed by a postemergence herbicide. This application strategy is similar with Roundup Ready soybeans. The local crop protection retailer, sales representative, or university agent has more information on selecting the most appropriate weed management strategies for growers' individual fields.

by  Editor, theCity1.com
August 8, 2005