FMC to Launch First New Herbicide Mode of Action in Nearly 40 Years

FMC has introduced two new herbicides, Keenali Complete and Keenali GR herbicide powered by Dodylex active, pending EPA decision. They are scheduled to launch for rice growers in 2027 and 2028, respectively. This is the first new herbicide mode of action in the industry for nearly 40 years. 

Dodhylex active is the FMC product for the active ingredient tetflupyrolimet, which has been classified as a Group 28 herbicide by the Herbicide Resistance Action Committee and the Weed Science Society of America. 

“It’s been more than 35 years since a new mode of action came into the marketplace,” said Lawson Priess, a FMC U.S. technical service manager for Arkansas, Louisiana, Mississippi, and the bootheel of Missouri. “This is the first new herbicide in my lifetime to come into the row crop space.”

Dodylex Active works by by inhibiting the DHODH enzyme in primidine biosynthesis pathway, thus stopping germination and tissue growth. While it does offer some post- activity, it will primarily be positioned as a preemergence residual herbicide. “In rice, in particular, barnyardgrass has evolved resistance to five different modes of action,” Priess said. “Dodylex has really great control of barnyardgrass, large crabgrass, signalgrass, and sprangletop species, and suppression of broadleaf signalgrass.”  

Keenali Complete herbicide will be a co-pack offering,which combines Dodhylex Active with Command 3ME microencapsulated herbicide (clomazone). Combining these two actives as a co-pack offers full-spectrum control, lengthens the time of residual activity, and increases stewardship of the new active ingredient to withstand resistance development. 

Barnyardgrass is the No. 1 problem weed in rice, said Conner Webster, assistant professor and rice extension weed specialist at Louisiana State University. “Our research shows tetflupyrolimet (Dodylex Active) tends to have a little longer residual. When paired with Command herbicide, it shows synergistic interaction to control barnyardgrass. Together you also get a little bit longer window of residual control. That can potentially buy you some time when you have to make a post-emergent application.”

“Command rates in rice vary greatly based on soil type,” Priess said. “Having that co-pack gives farmers some flexibility on how much Command they apply based on their soil texture.” 

Keenali Complete herbicide has demonstrated crop safety, as well as a fit across rice trait platforms along with a variety of cultural practices, including direct- and water-seeded rice production. “Because most of the applications in rice are made by air,” Priess said, “the potential for injury on off-target movement is very low for Keenali Complete.”

Keenali GR herbicide will be commercialized in 2028 as a stand-alone preemergence residual herbicide for the California rice market to control barnyardgrass, late watergrass, and sprangletop. 

“We are offering it as a solo active ingredient in the California market, and recommending that it is applied with other effective modes of action,” said Matt Kampschnieder, U.S. FMC portfolio manager for herbicides and fungicides. 

Because of the spectrum of weed species controlled (primarily grasses), the focus for the Keenali herbicides has been rice. However, the struggle to control resistant grassy weeds like barnyardgrass extends to corn, soybeans, and cotton, as well. “As those problems expand, there may be opportunities for pre-mixes in other crops as well,” Kampschnieder said. 

Pending EPA decision, FMC anticipates launching Keenali Complete herbicide in 2027 for the Mid-South rice growing region and Keenali GR herbicide in 2028 for the California rice growing region. For more information on Keenali GR and Keenali Complete herbicides, and Dodhylex active, visit ag.fmc.com.