BASF issues new call to action in weed management
“I spend a lot of time with growers discussing and recommending programs for weed management,” said Micheal Owen, Ph.D., Iowa State University Agronomy Professor. “I try to get them to recognize the necessity of proactively managing for the ultimate and inevitable evolution of herbicide resistance.”
Growers can stay ahead of resistance and tough-to-control weeds for the next season by closely monitoring the growth of weeds in their fields throughout the year. By identifying weed populations that did not respond to treatment, growers can plan for an effective weed management program the next year. The International Survey of Herbicide Resistant Weeds provides an excellent resource, at http://lists.serverhost.net/link.php?M=32793635&N=30513&L=29962&F=H, for identifying weeds and tracking the spread of resistance by location, site of action and weed.
Tip #3: Correct the strategy
Growers need a well-planned, strategic approach to make sure they incorporate at least two herbicides with different sites of action in a single growing season.
“Gone are the days of a one-pass glyphosate system for total weed control,” Westberg said. “Ultimately, growers need to go back to a time when planning and implementation of a comprehensive weed management plan based on the needs of their farm were vital.”
First, growers should identify the sites of action for their herbicides. A herbicide’s product label should identify the site of action. If growers are still unsure, they can contact a retailer, herbicide manufacturer, or a crop advisor.
Next, growers should consider application timing. Growers can apply herbicides at multiple times during the season, which enables them to choose from a greater diversity of herbicide sites of action. For example, a burndown and residual herbicide application in the spring enables a grower to select from a number of different herbicides that incorporate different sites of action and helps growers start clean and stay clean all season long. This can be followed by a post-emergence application that uses a different site of action to eliminate any late-season weeds competing for a crop’s resources.
“By selecting herbicides with different sites of action during the course of the growing season, growers can effectively reduce the selection pressure on any single site of action,” said Westberg.
In hard-hit fields where two sites of action may not be enough, a fall burndown provides the opportunity to select another site of action. This tactic helps growers stay ahead of tough-to-control winter annual weeds, such as marestail, and begin the following spring with a clean slate.