As rice growers know only too well, barnyardgrass doesn’t stay in the barn yard. It likes wet and moist areas and thrives in road ditches, irrigated crop fields, pastures and – much to farmers’ dismay – in their rice fields.
Yield losses of 30% or more are common in many rice growing regions. Losses have been amplified with the increase of herbicide-resistant barnyardgrass, which can often withstand applications of products with glyphosate, propanil and ALS chemistries.
“In terms of the spectrum of control, barnyardgrass is our number-one weed, and we need help,” says Connor Webster, assistant professor and rice Extension weed specialist at Louisiana State University (LSU), in an industry press release.
New Technology On The Way
Webster and several other weed scientists have conducted research on a promising chemistry, tetflupyrolimet, designed to help farmers manage herbicide-resistant barnyardgrass biotypes, sprangletop (Amazon and bearded) and other grass species.
Earlier this week, FMC U.S. announced it plans to introduce two new herbicides based on tetflupyrolimet, which FMC has branded as Dodhylex active. The products have been named Keenali Complete and Keenali GR.
The company anticipates introducing Keenali Complete herbicide in 2027 for the Mid-South rice growing region and Keenali GR herbicide in 2028 for the California rice growing region, reports Darren Dillenbeck, vice president and president of FMC North America.
The Dodhylex (tetflupyrolimet) technology has been classified by the Herbicide Resistance Action Committee and the Weed Science Society of America as a Group 28 herbicide, making it the first new herbicide mode of action globally in nearly 40 years.
“We have spent more than a decade at our Stine Research Center and in fields across the world researching, developing and testing these herbicides,” Dillenbeck says in the release.
Dillenbeck anticipates Keenali Complete herbicide will be a co-pack offering, combining Dodhylex active with Command 3ME microencapsulated herbicide, to harness their complementary spectrum while providing built-in herbicide resistance stewardship for both active ingredients. This use of multiple modes of action in a co-pack is a proactive step by FMC to protect the new Dodhylex active and provide technology better able to withstand resistance development.
Residual Control With Crop Safety
Keenali Complete herbicide will give rice growers two modes of action to use at the preemergence application stage. This solution will be commercialized and marketed to the Mid-South rice growing region (Arkansas, Louisiana, Mississippi, Missouri and Texas. Rigorously tested in all rice herbicide platforms, Keenali Complete herbicide will provide additional residual grass control and demonstrated crop safety, as well as fit with a variety of cultural practices, including direct- and water-seeded rice production, FMC reports.
Webster says research at LSU shows tetflupyrolimet tends to have a little longer residual. “Now, when paired with Command herbicide, the two together show synergistic interaction to control barnyardgrass, which we’ve seen consistently over the past four years of research. That’s a big positive. Having the two together is better than either one of them separate, plus you get that little bit longer window of residual control. That can potentially buy you some time when you have to make a postemergent application, and being able to buy time is critical,” he says in the release.
Jason Norsworthy, distinguished professor and weed scientist for the University of Arkansas System Division of Agriculture, says he is excited by the extended residual control of barnyardgrass and sprangletops the new chemistry offers.
“Also, based on carryover and drift research with Dodhylex active, I think rice growers will be pleasantly surprised to see how well it can be applied without fear of injuring nearby crops,” Norsworthy adds.
Flexible Use Options For California Growers
Work at the University of California-Davis has shown the herbicide can address a wide range of herbicide-resistant grass weeds. Some species of grass weeds there are resistant to all currently registered herbicides in the state, according to Kassim Al-Khatib, the Melvin D. Androus endowed professor for weed science at the university.
“We have tested tetflupyrolimet (Dodhylex active) on more than 50 grass populations of resistant grass weeds and we controlled all of them. This herbicide is also effective on bearded sprangletop where we do not have many alternatives,” Al-Khatib says. “Also, this herbicide fits in many programs — tank mixed or sequential application — to control weeds.”
Your next read: Proof of Concept: Regenerative Technology Reduces Methane Emission in Rice Production
