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Bringing a needed new mode of action to cotton weed controlBringing a needed new mode of action to cotton weed control

Weed scientist Charlie Cahoon says the new Axant Flex technology with Alite 27 brings a new mode of action for weed control in cotton.

John Hart

September 29, 2023

5 Min Read
Graduate Student Jacob Forehand
Graduate Student Jacob Forehand holds a poster describing research comparing Alite 27 to other modes of action as a preemergent herbicide for palmer Amaranth control as North Carolina State University Extension Weed Specialist Charlie Cahoon explains the research at the North Carolina Cotton Field Day Sept. 14 in Rocky Mount. John Hart

Weed scientist Charlie Cahoon is excited about potential benefits to cotton farmers of using the new Axant Flex cotton in combination with Alite 27 herbicide.

BASF recently announced that its new Axant Flex cotton will be available for the 2024 growing season. The use of Alite 27 with Axant Flex cotton is still awaiting regulatory approval from the EPA. In a news release, BASF said following EPA approval, Alite 27 can only be used with isoxaflutole-resistant soybean or isoxaflutole-resistant cotton. The company said crops not containing a gene expressing an HPPD protein will not be tolerant to Alite 27 herbicide.

Cahoon says he is excited because the new Axant Flex technology with Alite 27 brings a much-needed new mode of action for weed control in cotton.

“We are losing herbicides to resistance, losing them to regulation, so we’re looking forward to having an additional mode of action mostly for residual pigweed control. This is a new site of action for residual weed control in cotton. It was brought to the market for palmer pigweed because of all of the resistance issues we are having with palmer pigweed. We have also looked at it on common ragweed and have had some decent success,” says Cahoon, North Carolina State University Extension weed specialist for corn and cotton.

Research takeaways

At the North Carolina Cotton Field Day Sept. 14 at the Upper Coastal Plain Research Station in Rocky Mount, Cahoon highlighted ongoing research conducted by Cahoon and his N.C. State colleagues on Axant Flex and Alite 27. He said one takeaway from the research is that the technology provides good control of both pigweed and common ragweed.

Axant Flex cotton is genetically engineered to provide cottonseed varieties with a stacked herbicide trait package that provides tolerance to four chemical modes of action: dicamba, glufosinate, glyphosate, and Alite 27. Cahoon says the active ingredient in Alite 27 is isoxaflutole, an HPPD inhibitor.

Cahoon said Alite 27 has been used in corn, but it has not been used in cotton. The Axant Flex trait will allow Alite 27 to be used preemergence in cotton, pending EPA regulatory approval. Cahoon said he doesn’t know when EPA will give Alite 27 the greenlight for cotton.

“Alite 27 could also be labeled as an early post application. And that’s a big deal because our residual post herbicides right now all come from the same class of chemistry, things like Dual, Warrant, Outlook.  They are all Group 15s. We could eventually have resistance to that mode of action here (in North Carolina), so being able to use this residual in an early post application, that would be another site of action that we could change things up potentially for pigweed in particular and not put so much selection pressure on the Group 15s,” Cahoon said.

Comparing to other herbicides

Cahoon noted that in recent history all of the herbicides traits that have been brought to market were post-emergence products. Alite 27 is different because it is a residual product. He said he wondered how many cotton farmers would get excited about a residual herbicide trait.

“For a cotton grower, peace of mind with a residual means a lot. We can have some residual peace of mind with having a trait that confers tolerance to it versus just depending on the natural tolerance of that crop,” Cahoon said.

In the NC State research, Cahoon and his colleagues examined Alite 27 in comparison with the herbicides Direx, Cotoran, and Brake. He noted a big difference was found between Alite 27 and the other compounds in 2019 and 2020.

“In 2019, Alite 27 by itself looked good, much better than some of these other products. In 2020 the exact opposite happened. Rainfall was the difference in this trial. In 2019, we got a little bit of rain, not much, just a spit of rain. In 2020 we received over two and a half inches a couple of days after planting. This product is fairly water soluble. It will work a little better when we get lighter amounts of rain. But if we get a pounding rain, two three inches, it’s going to move fairly well and may move past our weeds seeds in the soil,” he said.

Other chemistries needed

Cahoon made it clear that Alite 27 will not work as a standalone product in cotton weed control. It needs to be used with other chemistries. He said Alite 27 will offer exceptional weed control when used with such products as Brake, Direx, Reflex, or Cotoran.

He said the common ragweed control benefits of Alite 27 came as a surprise. The NC State researchers looked at ragweed control in three different locations across the North Carolina cotton belt.

“We consider Cotoran our standard for ragweed control in cotton, kind of the opposite of Direx.  Direx works better on pigweed. Cotoran works better on ragweed. Alite 27 outperformed Cotoran. Brake may also have a place for residual ragweed control. It looks encouraging what we’ve seen from it. Reflex, if we hit the rains right, does a really good job on ragweed as well,” he said.

Cahoon said the common ragweed control of Alite 27 is really important due to the limited options available for residual control of ragweed, even compared to pigweed. He said there are more residual control options for pigweed so the ragweed control benefits is welcome news because it provides another effective mode of action.

Not a sole residual option

Cahoon emphasized there are places where Alite 27 will not be used. It won’t be used as a solo PRE, and it will not be “something that can just go out by itself, with the expectation of having clean cotton for the entirety of the season.”

“It is also not a post. And I know that’s going to be a hard lesson for folks to learn. When they see a new herbicide trait, they’re going to think the weeds can come up, and I can spray it over top, it should clean everything up. That is not the case,” he said.

Alite 27 will not work on emerged pigweed without another herbicide to control it. “It is not a post-emergent product. It is a residual,” Cahoon emphasized.

He said Alite 27 works as a post residual option and should be used in tandem or rotation with the Group 15 herbicides, but it will not be the sole residual option in your herbicide program. “Otherwise, we are going to end up with resistance,” Cahoon stressed.

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About the Author(s)

John Hart

Associate Editor, Southeast Farm Press

John Hart is associate editor of Southeast Farm Press, responsible for coverage in the Carolinas and Virginia. He is based in Raleigh, N.C.

Prior to joining Southeast Farm Press, John was director of news services for the American Farm Bureau Federation in Washington, D.C. He also has experience as an energy journalist. For nine years, John was the owner, editor and publisher of The Rice World, a monthly publication serving the U.S. rice industry.  John also worked in public relations for the USA Rice Council in Houston, Texas and the Cotton Board in Memphis, Tenn. He also has experience as a farm and general assignments reporter for the Monroe, La. News-Star.

John is a native of Lake Charles, La. and is a  graduate of the LSU School of Journalism in Baton Rouge.  At LSU, he served on the staff of The Daily Reveille.

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