Frustrated by pigweed, North Carolina farmers added more modes of action to their herbicide programs in 2011 and got cleaner cotton fields.
Allen Ginn, who farms cotton in a conventional-tillage system, believes he did a better job of controlling weeds in his cotton in 2011 than he did in 2010 by using more residual herbicides in his weed control program.
“Our cotton was cleaner this season because we took a no-tolerance approach to pigweed control,” he says. “Our program began with incorporating Trifluralin prior to bedding up two weeks before planting. After we received a rain, we planted cotton and put out Reflex plus Diuron behind the planter.”
Multiple Modes Of Action
After cotton emerged and grew to first true-leaf stage, he applied Roundup PowerMax plus Warrant herbicide over the top. Twenty-one days later, he made another application of Roundup plus Warrant – something he did not do in 2010. Three weeks later, he made a layby application of Diuron plus MSMA.
“I feel good about the performance of the residual herbicides, especially Warrant,” says Ginn. “We got the moisture needed to activate it, and many of our fields were clean after that first application. We went ahead and put out another application of Roundup because the cost to do so is low. We added Warrant in there with it because I felt like we needed longer residual control.”
Not too far from Ginn, Audie Murphy farms cotton in a strip-till system. In 2011, he also increased the number
of residual herbicides used in his weed management program and saw better results.
Murphy burned down with Roundup and 2,4-D on March 1, mainly for problem weeds at that time, such as bluegrass and marestail. Two weeks prior to planting cotton, he applied two ounces of Valor per acre. He then came back with Reflex and Diuron behind the planter. After cotton emerged and grew to the one true-leaf stage, he applied Roundup plus Warrant over the top. The rest of the applications were done as needed and where needed. Some fields required an over-the-top shot of Roundup plus Staple.
“Where we got Warrant activated, we did not need another herbicide application in our cotton this season,” says Murphy. “We had to hand-pull a few pigweed escapes here and there, but for the most part, Warrant did a great job for us. On a limited number of fields we had to come back with that hot shot of Roundup plus Staple.”
Most of Ginn’s acres are planted to Deltapine cotton varieties, but he also planted cotton varieties that allowed him to spray Ignite herbicide over the top on his fields with the worst pigweed problems. However, Ginn knew that Ignite by itself was not the answer to his problems.
“In our Ignite-tolerant cotton, we did the same residual herbicide program that we did in our Genuity Roundup Ready Flex cotton except we replaced Roundup with Ignite herbicide,” he says. “You cannot leave residuals out of your program.”
Ginn and Murphy also know the value of the Monsanto Roundup Ready Plus cotton incentives platform.
“I could not afford to use as many residuals as we do without the cash back incentives,” he says. “It rewards guys for using multiple products and gives them incentives not to cut the rates on those products. That is a good thing, and more farmers need to adopt the system.”
Murphy takes advantage of the Monsanto Roundup Ready Plus incentives to help with the cost of adding multiple modes of action to his weed management regimen.
“I think Roundup Ready Plus provides good incentives to use residual herbicides in cotton,” he says. “We do believe we did a better job of managing weeds in our cotton using the residual program. The big addition was Valor. I believe in Valor. It will wait for rain for activation longer than most residuals. A two-ounce shot of Valor keeps the row middles clean.”
Monsanto contributed information for this article.
Progress Being Made Against Weed Resistance
The good news for North Carolina cotton producers is that they are seeing immediate results in their efforts to control resistant pigweed.
That is a significant development, according to North Carolina Extension cotton specialist Keith Edmisten. He says the important lesson for his state’s producers is that they can’t depend on one chemistry in battling resistance.
“If we wind up depending on just one chemistry, we run the risk of developing problems that we’re now having with pigweed,” he says.
“The only way to prevent this problem is to incorporate other chemistries. The situation with cotton also entails some pre-emerge activity.”
Edmisten emphasizes that the residual program approach is not bulletproof if a farmer doesn’t receive enough moisture to activate the herbicides in some reduced tillage acreage.
The veteran Extension cotton specialist also had high praise for all of the companies working together to find a common approach to deal with the resistant pigweed problem.
“It’s very encouraging when you see this happen because it can be any company’s product that can be affected by resistance if you don’t use all of the products correctly,” Edmisten says.