As growers across the Corn Belt prepare for harvest and scout their fields, they may see an increased level of weed pressure due to summer rains, which may have delayed postemergence herbicide applications.
Harvest is an ideal time to examine a weed control program assess weed infestation and evaluate herbicide efficacy. For Midwest growers who were unable to make postemergence applications because of heavy rain during peak growing season, it's an ideal time to evaluate and think about using a preemergence herbicide program next spring.
Evaluating a herbicide program is fundamental to managing resistance and preventing the same weed problems from occurring next year no matter what the weather brings, says Luke Peters, corn herbicides product manager, Dow AgroSciences.
"Implementing a resistance management strategy is no longer an option; it's a necessity, Peters says. "The first step in building a strategy is evaluating your current program at the end of the growing season to determine what worked in your field. This will help growers craft an improved weed control program for next year that mitigates resistance issues.
These tips can help evaluate herbicide programs and maximize weed control next year:
- Adjust. Switch to a program approach that uses multiple modes of action, which is vital to control herbicide-resistant weeds. Glyphosate resistance was the main reason lifelong Missouri grower Jimmy Daniels started using a preemergence herbicide. Daniels, who farms 1,500 corn and soybean acres, has seen waterhemp become increasingly difficult to control over the years and why he switched to a multiple mode of action herbicide program.
- Scout often. Scouting fields during harvest will help determine which uncontrolled weeds compete with crops for essential nutrients during peak growth stages. A field's weed spectrum at harvest is a good indication of which weed problems will be lurking at planting next spring.
- Consider a residual herbicide. Residual herbicides are increasingly important to control early season weeds and make control easier later in the season. Daniels says his fields went from being heavily weed-infested to clean during the growing season.