Tall Waterhemp Escapes…Resistance or Something Else?
It’s no secret Tall Waterhemp populations are very high in many soybean fields this year. The question on many minds is if there is Tall Waterhemp resistance to a specific class of chemistry such as PPO herbicides, glyphosate, both or neither. If resistance does exist within a field, selection pressure from using the same herbicide in the same way can increase resistant weed populations exponentially within just a few years. If no resistance is found, continuing to use the same herbicide program such as straight glyphosate will undoubtedly select for a resistant population in short order-it’s just a matter of time. Ask yourself, how did weed resistance to herbicides even begin?…by using the same chemistry year after year.
Sampling Tall Waterhemp for Herbicide Resistance
In recent weeks, growers have been pro-active with the help of United Prairie Sales Agronomists in collecting tall Waterhemp samples to be tested for PPO and glyphosate resistance at the University of Illinois Plant Clinic located in Turner Hall on campus. The Plant Clinic has a nominal charge of $50 per sample however our staff are available to properly collect and deliver samples to the clinic for analysis. Results may take up to 2 weeks to complete. A single sample is all that is needed for any specific field.
Confidence about what herbicide program mix will be most effective in your field(s) in the future begins with knowing what weeds are problematic and an awareness of any weed resistance to commonly used herbicide classes. In building a plan consider at least (3) modes of herbicide activity which includes layering residual herbicides for Tall Waterhemp season-long control. The best approach is control before it emerges. Please contact your United Prairie Sales Agronomist for more information.