The combination of dry weather early and during the growing season, rushed planting, some missed pre-emergence herbicide applications and the increased presence of glyphosate-resistant weeds has left some Texas High Plains cotton and grain fields a bit more weedy than usual this fall.

“I’ve seen some bad fields, some that will be hard to harvest,” says Gaines County AgriLife Extension integrated pest management specialist Manda Anderson. “I think we have some resistance but we also have some issues with application.”

Mother Nature, Anderson says, was not cooperative. “Soil was very dry and humidity was so low plants couldn’t take up the product. Application timing was also an issue.”

She says another contributing factor would be some farmers “not getting yellows down. That’s not an expensive system if we get the products out at the right time. Starting clean is the key to good weed control.”

She says if weeds are present before planting, “burn them down. Also, treating small weeds is important. A 4-inch weed target is the key. Weeds are tough and will not take up herbicides as effectively as they get bigger.”

Anderson said weedy fields result from several factors. “But we have to use herbicides other than Roundup (glyphosate). It’s also important to get a second application on.”

Monti Vandiver, IPM specialist for the Northwest region, in Muleshoe, has also noticed a significant number of escapes, both herbicide-resistant and weeds that were missed for one reason or another.

 

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“I have definitely seen resistant weeds,” Vandiver says, “but I also believe other issues have played a significant role in weed control failures. In some cases, it has become convenient for us to blame resistance when weeds are not controlled by glyphosate.”

Regardless of the reason, a more prescribed approach to management will improve control, he says. “Whether a control failure was actually a result of resistance or not, if production practices which combat resistance development are implemented dividends will be paid in the future.”

Texas AgriLife Research agronomist Wayne Keeling, at the Research and Extension Center in Lubbock, says he’s seeing two distinct issues this fall, “escapes and resistant escapes.