Syngenta advances new ACCase-inhibitor for resistant weeds

After more than a decade of research, a new herbicide from Syngenta called metproxybicyclone has been recognized under a new chemical subclass. The decision, by the Herbicide Resistance Action Committee and the Weed Science Society of America, will allow farmers to better combat grass weeds that have evolved resistance to existing herbicides.

“Herbicide resistance has been officially reported in 75 countries and affects farmers of more than 100 crops; of the 273 weed species afflicted, 40 percent are grass weeds,” said Camilla Corsi, Syngenta’s Global Head of Research and Development.

Weeds compete with crops for resources such as water, nutrients and sunlight, and lower yields in major crops by as much as 43 percent, Syngenta notes, and the evolution of herbicide resistance in many weed species today poses a serious and growing threat to many farmers around the world, limiting yield and — in extreme cases — destroying the value of the land.

Corsi said that Syngenta scientists foresaw that certain grass weeds in Argentina and Brazil would likely evolve resistance to existing herbicides, which spurred work on developing metproxybicyclone in time to support soybean and cotton farmers who now confront this challenge. Subject to regulatory approvals, the new herbicide is expected to be introduced in Argentina in 2026.

Metproxybicyclone’s has been distinguished as the fourth generation of ACCase-inhibitors, an important class of herbicides. Scientists precisely designed this herbicide, which was invented at its International Research Centre at Jealott’s Hill, United Kingdom, to be capable of controlling grass weeds that had evolved resistance to herbicides such as glyphosate and clethodim, while optimizing the molecule’s sustainability profile.

The previous generation of ACCase-inhibitors, represented by Syngenta’s leading molecule pinoxaden, was launched in 2006. The company says that the nearly two-decade long gap in ACCase subclass innovation reflects in part the extreme challenges in finding new, effective, and safe solutions.

Especially over the past decade, innovation in herbicide technologies has surged in importance and urgency, reflecting the value of such technologies in controlling weeds and improving the sustainability of farming operations.