Abstract BACKGROUND The herbicidal efficacy and safety of flusulfinam (QYR601), a novel 4‐hydroxyphenylpyruvate dioxygenase (HPPD)‐inhibiting herbicide, were evaluated through post‐emergence (POST) trials in paddy fields under both greenhouse and field conditions in China. RESULTS Greenhouse assays revealed that flusulfinam applications (15, 30, and 60 g active ingredient (a.i.) ha −1 treatments) achieved 80–100% biomass inhibition of 17 weed species, including Echinochloa crus‐galli (L.) P. Beauv., Ludwigia prostrata Roxb., and Myosoton aquaticum (L.) Moench., but exhibited moderate efficacy against Descurainia sophia (L.) Webb. ex Prantl., Oryza sativa f. spontanea Roshev. and Bromus japonicus Thunb. ex Murr. Crop safety studies (180 and 360 g a.i. ha −1 ) indicated that rice was the only crop with no visible phytotoxicity, further tolerance evaluations demonstrated variable susceptibility among the 20 rice hybrids tested. Japonica varieties exhibited significantly higher tolerance than indica varieties. In addition, the selectivity index (SI) between two rice varieties and six weed species showed that the SI ranged from 13.12 to 93.36. Field experiments conducted in 2022 and 2023 established that flusulfinam application under the rates of 45–135 g a.i. ha −1 provided effective season‐long weed control. CONCLUSION This study highlights the potential of flusulfinam as a promising herbicide for sustainable weed management in rice cultivation, demonstrating exceptional efficacy against dominant weeds while maintaining crop safety, and thereby contributing to stable rice yields. © 2026 Society of Chemical Industry.
Li et al. (Mon,) studied this question.