High Plains Journal:
Residual herbicides are key to managing weeds in cotton
By Lacey Newlin
*This article was taken directly from the High Plains Journal - April 20, 2020 Edition
Spring is here and temperatures are heating up, allowing farmers to start planting cotton. However volunteer cotton and other undesirable weeds also start to pop up now, underscoring the needs for weed management and residual herbicides. Herbicides with long-ranging effectiveness that are applied after planting, but before emergence, are known as residual herbicides for their longevity.
Todd Baughman, Oklahoma State University row crops weed control specialist, said prior to planting he has had good success with Gramoxone and Aim as burndowns.
"Whether you're in a tillage or no-till situation, the first thing is you need to start clean to stay clean," Baughman said. "Cotton is fairly non-completive early in the season, so it is critical that you start out with a clean seed bed, whether you do that through tillage and rolling up beds or through your burndown program, it is very important."
However he said the key is making sure those applications go on volunteer cotton that has less than four leaves. If that cotton gets much bigger, the control of it goes down significantly."
"Cotton is one of those interesting plants early in the season when it's small, it's fairly easy to control, but once it gets a root system on it and some size, it can be quite difficult," Baughman said.
Baughman said the Xtend and Enlist herbicide products work well when alternating technologies. It is especially important with Etend to apply it on very small cotton. Baughman said there is a larger window with the Enlist, and is has had more success controlling larger cotton. Additionally, he said cultivation can help if weeds get out of hand. Baughman said he is hopeful with the winter rainfall that occurred this year weeds will not be as big of an issue with volunteer this season.
Baughman said the other thing to be cognizant of with burndown programs as producers move closer to planting, is they are getting into that fine-line window as far as rotation timing. Some of those products, like Sharpen and Quelex, could push growers close to the May 15 date, which is expected to be the optimal timeline for cotton planting in the southern Plains this year.
"We've seen the benefits of residual herbicides, especially in cotton, one of the slow growing crops," Baughman said. "That first four to eight weeks is the most critical time as far as potential yield loss. We've looked at several pre-emergence herbicides, like Cotoran, Diurex, Caparol, Warrant and Dual. Typically we see a little better control when we look at something like Diurex or Caparol compared to Dual or Warrant upfront. However, if we follow those up with our first or second post application, a lot of times those even out. I prefer to use Caparol or Diurex upgront and save those Warrant and Dual products to go out with our first or second post-emergence application because they fit that window and extend the residual and help us from a season-long weed control aspect."
Baughman said one of the reasons residual herbicides are so important is they not only provide a better opportunity to set up a post application, but they also allows producers to get another method and mode of action for weed control, especially in dealing with resistant weeds. This can increase the likelihood of adequate weed wontrol by giving the crop more time to emerge and reducing resistance pressure on post-emergence herbicides.
Lacey Newlin can be reached at 580-748-1892 or lnewlin@hpj.com.
*This article was taken directly from the High Plains Journal - April 20, 2020 Edition
KP
