Take Action Against Herbicide-Resistant Weeds

Weed resistance to herbicides is an economic problem. The United Soybean Board, in concert with the Weed Science Society of America, has developed an educational program called ‘Take Action’ that has been endorsed by several commodity and weed science groups, including Cotton Incorporated. The following educational bulletins were prepared for the Take Action program.

• The bulletin, ‘Best Management Practices for Herbicide Resistance’, enumerates field management tactics that are consistent with good crop production and environmental stewardship, and also retard the evolution of weed resistance to herbicides.
• The bulletin, ‘Economics of Herbicide Resistance’ illustrates that practicing crop and herbicide rotation can pay for itself in as few as 2 years and  the benefits are retained for the future. While the study presented was done with corn and soybeans, given the costs of resistance in cotton, we believe the benefits in a cotton rotation would be as great or greater than those demonstrated.
• Herbicides control weeds by means of a physiological Mechanism of Action (MOA). Herbicides with the same MOA select weed populations in the same manner. The ‘Herbicide Class Chart’ provides the MOA codes for many commonly used herbicides.
• In order to rotate herbicide mechanisms of action (MOAs), growers must be able to identify them. Numbers designating herbicide MOAs are now on herbicide labels. The bulletin, ‘How to Use the Herbicide Classification Chart’ lists the codes for many commonly used herbicides and illustrates to use of the chart with examples.
• Should control failures occur, the bulletin, ‘Field Identification and Control of Suspected Herbicide Resistance’ shows how to identify suspected resistance by observation of the effects of herbicide application on weeds in the treated field.