Fendioxypyracil, a new and systemic PPO-inhibiting herbicide for X-spectrum weed control

Abstract

BackgroundFendioxypyracil is a novel protoporphyrinogen oxidase (PPO)-inhibiting herbicide (HRAC Group 14) developed to address the increasing prevalence of herbicide-resistant weeds and to expand available weed control options. PPO inhibitors disrupt chlorophyll biosynthesis by blocking the conversion of protoporphyrinogen IX to protoporphyrin IX, resulting in light-promoted formation of reactive oxygen species and rapid plant necrosis. Building on established PPO chemistry, fendioxypyracil incorporates a pyridine-based core and an aryloxy sidechain designed to enhance binding affinity and post-emergence activity. ResultsGreenhouse evaluations demonstrated high efficacy of fendioxypyracil against key grass weeds, including wild oat (Avena fatua), crabrass (Digitaria Sanginalis), goosegrass (Eleusina indica) and barnyard grass (Echinochloa crus-galli), as well as strong control of major broadleaf species. Physiological characterization and enzyme inhibition assays confirmed PPO as the primary site and mode of action, with IC values lower than those of the commercial standard saflufenacil for both PPO isoforms. ConclusionFendioxypyracil represents a next-generation PPO inhibitor with broad-spectrum and systemic activity, offering a valuable new tool for integrated weed management. Its high biological activity and efficacy across multiple weed taxa supports its potential to enhance on-farm weed control strategies and contributes to resistance management programs.