This article was originally published July 24, 2018, in Successful Farming.
The Enlist weed-control system that features tolerance to 2,4-D choline is a go for cotton. Ditto for corn. Soybeans?
Well, all is a go for a widespread commercial U.S. launch except for a familiar sticking point that caused the system that includes tolerance to 2,4-D not to widely commercially debut in 2018.
“We continue to seek import approval from China,” says Shawna Hubbard, product marketing manager with Corteva AgriScience, agriculture division of DowDuPont. Once approved, it’s a go. In the meantime, Corteva AgriScience is concentrating on stewardship of the soybean launch, she says. Hubbard and other Corteva AgriScience officials updated members of the agricultural media at a field day last week near Lebanon, Indiana.
The Enlist system confers herbicide tolerance to a new 2,4-D formulation—2,4-D choline—and glyphosate in corn, soybeans and cotton, and fop herbicides in corn. Herbicide options include Enlist Duo, a mix of glyphosate, and 2,4-D choline. Enlist One is straight 2,4-D choline that can be tank mixed with approved label herbicides.
“We don’t recommend Enlist One be used alone,” says Hubbard. However, she says it gives farmers flexibility to mix with labeled products designed to match weeds in their fields.
Corteva AgriScience officials say it’s also important to use a pre-emergence product and also to use multiple effective modes of action as means to forestall resistance. “It is important to preserve the efficacy of each of them, so we continue to have (herbicide weed-control) options,” she says.
Corteva AgriScience officials say these herbicides that contain 2,4-D choline have an 87% and 96% reduction in volatility compared with existing 2,4-D amine and 2,4-D ester formulations, respectively. Meanwhile, Enlist Duo cuts drift potential 90% compared with older 2,4-D formulations when applied using low-drift-potential nozzles, say Corteva AgriScience officials.
Enlist E3 soybeans that can tolerate glyphosate, 2,4-D choline and glufosinate are available this year via a closed-loop system to select growers through Brodbeck Seeds, Dairyland Seed, Mycogen Seeds, Pfister Seeds and Prairie Brand Seed. If China gives approval, a full widespread commercial launch in soybeans ranging from relative maturity groups 0 to 5 will occur for 2019, says Hubbard.
“If I could say there is one silver lining—or perhaps as Dave Hillger, Corteva AgriScience field specialist) puts it—an aluminum foil lining to our later anticipated launch date—is that it has given us a chance to refine our breeding program,” Hubbard says. “We have even more zeroed in on the best varieties for a particular maturity.”
She adds that the herbicides available for use on Enlist E3 soybeans gives farmers flexibility and the ability to customize their weed-control programs.
The later anticipated launch date has also given Corteva AgriScience officials a chance to observe what’s gone on with dicamba and off-target applications. “One thing we have learned from others is the need for a swift investigation and resolution of off-target concerns,” says Hillger. “It can be emotional when off-target movement occurs. You certainly do not want that emotion to fester and build because you are waiting for a company representative to come out and talk to you.
“Communication is important,” he adds. It can be difficult keeping track of competing herbicide-tolerant systems due to switches in land rental agreements. Still, Hillger says communication and planning with neighboring farmers ahead of time can help head off the potential for off-target situations.
“This is not a system where you can forget about using other modes of action,” says Hillger. “So, keep fundamental weed science management principles in place.”
Farmers still need to get in their fields and scout, says Dave Roome, customer technical specialist for Corteva AgriScience. That’s not only the case for the present year, but upcoming years, as well, he says. Documentation of current weeds during the growing season can help with future weed-management decisions, he says.
Waterhemp, of course, remains public enemy number one for weeds in the Midwest, he says. Still, Palmer amaranth is also present. “Giant ragweed is coming back in full force in Indiana and in the Midwest,” adds Roome. “We are also seeing lots of the viney weeds like bindweed. Also, green and yellow foxtail are coming back.”
Following are other weed-management tips.
Properly identify weeds. Waterhemp and Palmer amaranth can resemble each other. One way that normally works to tell them apart is petiole length. Palmer amaranth’s petiole is longer and often exceeds the lengths of one of its leaves. As a rule, waterhemp’s petioles are shorter than the leaf length, Roome says.
Apply herbicides at optimum weed height. If the label states to spray weeds at a 4-inch height, spray them at that height. Not only will limited control result at a height like 8 inches, but also the taller weeds will shield smaller weeds and block the spray, Roome says.
Adopt cultural practices. Soybeans in narrow rows will canopy sooner and thus shade weeds earlier. Roome says there are varieties of soybeans that perform better under narrow rows.
Hone application technology. “Some farmers and applicators do a great job of paying attention to gallonage, pressure and nozzles,” says Roome. “Also, the boom needs to be 20 to 24 inches above the targeted species. Ideally, nozzles should overlap each other. Booms above this recommended level can apply varying amounts of herbicide. Some weeds can get 175% of the (labeled) herbicide rate, while others get 10%,” he says.
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About the Author: Gil Gullickson