The herbicide fendioxypyracil enhances post-emergence control

A new protoporphyrinogen oxidase (PPO) inhibitor herbicide emerges as an alternative for post-emergence weed management. Fendioxypyracil exhibits systemic activity and broad-spectrum control of grasses and broadleaf weeds, with high efficacy at low doses.

The compound acts on PPO1 and PPO2 enzymes, which are linked to chlorophyll and heme biosynthesis, explain the scientists involved in the project. The inhibition blocks the conversion of protoporphyrinogen IX into protoporphyrin IX. The accumulation of this intermediate leads to the formation of reactive oxygen species under light. The process causes membrane damage, necrosis, and plant death.

Mode of action

Biochemical assays confirmed the mode of action. Fendioxypyracil showed lower IC50 values ​​than the commercial standard saflufenacil for both enzyme isoforms. The result indicates greater potency, especially in PPO2 Amaranthus tuberculatus.

Physiological evaluations reinforced the mechanism. The herbicide induced rapid necrosis in tissues exposed to light and strong growth inhibition. CO2 uptake decreased significantly. There was no direct inhibition of photosystem II; the effect is light-dependent. The physiological profile aligned the compound with other PPO inhibitors, with a probability greater than 99% for this mode of action.

Broad spectrum

Greenhouse trials demonstrated broad spectrum control. The product controlled grasses such as Avena fatua, Digitaria sanguinalis, Eleusine indica and Echinochloa crus-galli. Broadleaf weed control also occurred consistently, explain the researchers involved in the project.

The effectiveness was demonstrated under different environmental conditions. Experiments included greenhouses with temperatures between 12°C and 24°C. Visual assessment indicated high levels of weed damage a few days after application.

The molecule combines a pyridine core with an aryloxyl side chain. This structure favors fitting into the enzyme's active site. This configuration increases biological activity and contributes to field performance.

More information at doi.org/10.1002/ps.70763