The novel herbicide icafolin-methyl is a plant-specific inhibitor of tubulin polymerization

Background: Without controlling weeds, it is estimated that about one third of global crop yields would be lost. Herbicides remain the most effective solution for weed control, but they face multiple challenges, such as the emergence and growth of resistant weed populations. Consequently, there is an urgent need for either herbicides with new modes of action or at least novel chemistries within established modes of action, with outstanding efficacy but without showing cross-resistance to the herbicides present in the prospective markets.

Results: Icafolin-methyl is a novel herbicide with a unique biological profile. It is hydrolyzed in planta to the carboxylic acid icafolin. After post-emergence application icafolin-methyl and icafolin both show high efficacy against the most relevant competitive weeds in cold and warm season cropping systems at low application rates, including resistant black-grass and rye-grass biotypes. Biochemical and genetic evidence is provided that icafolin-methyl and icafolin inhibit plant tubulin polymerization probably by binding to ß-tubulins.

Conclusion: Icafolin-methyl is a novel non-selective herbicide with an established mode of action, but with a superior potency and spectrum, specifically after foliar application. This makes icafolin-methyl fundamentally different from existing tubulin polymerization inhibiting herbicides. It complements the farmers weed control toolbox, particularly with respect to resistance management. © 2024 Society of Chemical Industry.

icafolin; icafolin‐methyl; mode of action; plant‐specific tubulin polymerization inhibitor; post‐emergence herbicide.