Design of highly leaf-adhesive and anti-UV herbicide nanoformulation for enhanced herbicidal activity

Abstract

• TA-Fe complex-coated MSNs-NH 2 nano-carrier were established for herbicide delivery. • The gained MSNs-TA-Fe nanohybrid could effectively protect CB from photodegradation. • CB@MSNs-TA-Fe exhibited markedly enhanced surface wettability and foliar adhesion. • CB@MSNs-TA-Fe showed superior control efficacy against barnyard grass. • CB@MSNs-TA-Fe revealed excellent biosafety to rice, zebrafish, and earthworms. Conventional pesticide formulations have been widely used to boost agricultural productivity, but their weak foliar adhesion and instability under UV light during spraying lead to low utilization rates and potential environmental and health hazards. To counter these challenges, the development of nanoformulations represents a pivotal strategy. These advanced formulations are designed to enhance the efficacy of active ingredients (AIs) and reduce ecological impacts, thereby addressing the need for sustainable agricultural development. The study aims to fabricate a highly leaf-adhesive and anti-UV herbicide nanoformulation, designed to enhance the herbicidal activity and utilization rates of AIs. Herein, the herbicide nanoformulations (Called CB@MSNs-TA-Fe) are synthesized by incorporating cyhalofop-butyl into tannic acid-Fe (III) ions-coated functionalized mesoporous silica. The foliar retention performance of the samples was assessed integrating SEM observation and HPLC analysis. The CB@MSNs-TA-Fe with rough outer surface displays typical core–shell structure featuring an average diameter of about 118 nm. After amino modification, the CB@MSNs-TA-Fe shows enhanced loading rate for CB (14.4 ± 0.2 %) and superior thermal stability. The release rate of CB within CB@MSNs-TA-Fe under acidic conditions is higher compared to that under alkaline and neutral conditions. Upon UV irradiation, the half-life of CB within CB@MSNs-TA-Fe nanoparticles is 12.4 times higher than that of CB technical (CB TC). Enhanced foliar adhesion of CB@MSNs-TA-Fe on hydrophobic leaf surfaces is observed, which can effectively mitigate the risk of wash-off by rainfall. The CB@MSNs-TA-Fe displays enhanced herbicidal efficacies against barnyard grass under UV irradiation or simulated rainwater scouring, compared with CB TC and CB oil dispersion. Furthermore, the TA-Fe-coated MSNs-NH 2 nano-carrier (MSNs-TA-Fe) reveals excellent biosafety on rice, zebrafish, and earthworms. The developed TA-Fe-functionalized herbicide nanoformulations, with high foliar adhesion and anti-UV properties, effectively improve the utilization efficiency of AIs, thus offering innovative solutions for the development of efficient pesticide formulations.

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