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Weed Management

Develop A More Diverse Program

Herbicide resistance has been around for decades in production agriculture, but only in the last decade has it exploded into an industry-wide phenomenon. Now, it is a reality for most growers or it will be soon.

Both researchers and growers have learned that an opposition to change is a recipe for resistant weeds. Resistance is more likely to develop in areas of widespread use of the same herbicide family. A diverse herbicide strategy that uses multiple mechanisms of action is required regardless of whether resistance is currently present.

Use All Tools Available
To develop a more diverse herbicide strategy, begin by using one of the highly effective preemergence herbicides. These herbicides provide effective weed control, and many have a low probability of resistance. Although these herbicides may require a greater investment “up front,” they will pay great dividends by preventing resistance and providing excellent weed control.

After this, at-cracking and very early post-emergence can help control that first flush of weeds, keep the crop clean during those critical first 40 days and then reduce the amount of weed seed germinating later in the season.

Timeliness and attention to cultural practices are also important components for an effective weed management program.

If You Suspect Resistance:
1. Contact your county Extension agent and/or state Extension specialist immediately. Plant material will need to be collected and experiments conducted before resistance can be confirmed or discounted.

2. Take steps to destroy the resistant plants before they can produce seed. If it is a localized patch, till it under or spray it sufficiently to ensure that the weeds die. It is better to sacrifice a small area than to have the entire field infested.

3. Work with your university Extension service to develop a diverse weed management system to address these resistant weeds. This may include crop rotation, implementation of tillage and/or incorporation of different herbicides.


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