Abstract: Benzovindiflupyr (BEN) has emerged as one of the fastest-growing SDHI fungicides in recent years, but it is considered "very highly toxic" to aquatic fish, invertebrates and crustaceans (EC 50 or LC 50 , 0.0035-0.056 mg/L, acute toxicity). The comprehensive study on bioactivity, toxicity, and degradation behaviors of BEN at the enantiomeric level would facilitate the development of a high-efficiency and low-risk application method. The bioactivities of 1S, 4R-(-)-BEN against five target pathogens (Alternaria alternata, Phoma multirostrata, Selerotium rolfsii, Magnaporthe oryzae, and Rhizoctonia solani) (EC 50 , 0.00562-0.329 mg/L, high-efficiency) were 6.7-1029 times higher than 1R, 4S-(+)-BEN, demonstrating significant enantioselectivity. For Danio rerio, 1S, 4R-(-)-BEN (LC 50 , 0.0360 mg/L, "very highly toxic") exhibited higher toxicity than 1 R, 4S-(+)-BEN, but the toxic interaction was concentration addition (TU rac , 0.94), indicating an enhanced toxicity in the presence of 1R, 4S-(+)-BEN. Molecular docking was employed to offer insights at the molecular level and elucidate the factors influencing enantioselectivity. The stronger binding affinity of 1S, 4R-(-)-BEN with SDH was in line with the quantitative experimental findings. The degradation of two BEN enantiomers in four different fruits followed the first-order degradation kinetics equation, and displayed enantioselectivity. The preferential degradation of 1R, 4S-(+)-BEN was found in pears and grapes, while varying enantioselectivity was found at different stages in tomatoes and watermelons. The residual concentrations of BEN in grapes were higher than the EU's MRL, which in the other three fruits were below the MRLs during the sampling. In conclusion, 1S, 4R-(-)-BEN proved to be the more effective monomer. Utilizing the pure monomer could not only reduce the dosage of racemate by about 44-59 %, but also mitigate the risk of introducing inefficient monomer into the environment (especially for fish).
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024. Published by Elsevier Inc.)
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