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Go After Problem Weeds with Postemergence Applications

Go After Problem Weeds with Postemergence Applications
Change the herbicide mixture to take down problem weeds.

If you've had a frustrating start to the crop year you may be burnt out and ready to fall back on your "tried and true" herbicide approach. If that's simply glyphosate with additives over the top of Roundup Ready crops, you may be adding to your frustration instead of simplifying things.

Jarrod Hudson, Team Sales Agronomist for Beck's Hybrids, made several key points in the April edition of Crop Talk, a newsletter published for Beck's Hybrids customers.

Identify weed species: What is the worst problem weed? Does it call for adding something extra to the tank? Are you already pushing the envelope on weed height? Adjust accordingly.

Hudson offers a few suggestions. First, think about post applications on soybeans like you did before the days of glyphosate. That means it's necessary to scout fields for weed species, weed height and weed pressure before you determine what to spray and how to spray it.

Second, evaluate weed height. Many labels suggest spraying most weeds at three to six inches tall. Many farmers push the label and spray up to 12 inches tall. Some even do it for tough weeds like lambsquarters. Sometimes they get by with it, but sooner or later they won't.

Third, note weed pressure. This may dictate herbicide rates and gallons per acre that you need to apply. Weed pressure may not be the same in all parts of the field. Scout the field to know what weeds and at what weed pressures you must control.

Fourth, identify weed species. It is important to determine if the main problem weeds in your field are grasses, broadleaves or vines, Hudson emphasizes. Knowing the main problem weeds will help you determine usage rates, and help you decide if you need to spike the mix with an additional herbicide to help control problem weeds.

For example, if morning glory is the main problem weed in your field and glyphosate is the planned postemergence herbicide of choice, an additional herbicide such as Flexstar or FirstRate will need to be added.

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