Targeted delivery of emamectin benzoate by functionalized polysuccinimide nanoparticles for the flowering cabbage and controlling Plutella xylostella.

Abstract

Plutella xylostella, one of the most destructive and cosmopolitan pests of cruciferous crops, is especially harmful to the young tissues of the flowering cabbage (Brassica campestris L.). Although emamectin benzoate (EB) has high insecticidal activity against P.xylostella, one major reason of low utilization for EB is the lack of internal transport in the young plants. In this study, four kinds of functional EB/polysuccinimide (PSI) with glycine methylester nanoparticles (EB@PGA NPs) were prepared. The obtained EB@PGA NPs could effectively protect EB from photolysis, and the degradation rate of EB@PGA NPs was <30% in 24 h. Simulating the intestinal pH=9 of P.xylostella, the highest cumulative release rate of EB@PGA NPs could reach 89.61% in 24 h. Furthermore, EB@PGA NPs could delivery EB into the young tissues of the flowering cabbage through the nanocarrier, and the highest transport efficiency of EB@PGA25 reached 1.437%. The bioactivity of EB@PGA25 against P.xylostella larvae (LC50 =0.34μg mL-1 ) was 1.6-fold higher than that of EB (LC50 =0.53μg mL-1 ). EB@PGA could easily become 'internalized' into the intestinal wall of P.xylostella, thus increasing the penetration of the drug and enhancing the insecticidal activity. The accurate delivery of insecticides by PGA nanocarriers into young tissues of plants could be a promising new method for the efficient management of field pests and diseases. © 2021 Society of Chemical Industry.