Dual-stimuli-responsive silica-based emamectin benzoate nanodelivery system for effective control of Spodoptera frugiperda and safety assessment toward Microplitis manilae

The utilization of highly efficient and ecofriendly stimulus-responsive delivery systems for pesticides represents a powerful strategy for enhancing their efficacy and environmental safety. In this study, the application of emamectin benzoate (EB)-loaded amino-functionalized rough mesoporous silica (KMSNs)@poly(glycidyl methacrylate-co-acrylic acid) (PMA) composites (KMSNs@PMA@EB, 6.52 % loading capacity for EB) to control efficacy for Spodoptera frugiperda was investigated in detail. The results showed that, KMSNs@PMA@EB rapidly released EB under acidic and high-temperature conditions. compared with EB and commercial formulations, a solution of KMSNs@PMA@EB with the agricultural organosilicon additive exhibited excellent wetting. Compared with MSNs, KMSNs@PMA significantly enhanced the effective deposition. Moreover, the photostability of KMSNs@PMA@EB was improved by 1.87-fold and 2.25-fold compared to EB and an EB suspension concentrate (EB SC). S. frugiperda larvae preferred corn leaves with low concentrations (0.125 mg/L) of KMSNs@PMA@EB than EB-treated. Bioassays revealed that KMSNs@PMA@EB maintained > 37 % control efficiency after 21 d of spraying, KMSNs@PMA@EB exhibited significantly greater insecticidal activity and persistence against S. frugiperda than commercial formulations. After 21 days of application, the final deposition rates of KMSNs@PMA@EB were lower than the maximum residual limit of EB, spraying KMSNs@PMA@EB has a lower impact on corn plants. Furthermore, biological safety assessments confirmed that KMSNs@PMA@EB did not affect the maize seed germination and growth and posed a low risk to Microplitis manilae . Those results highlight that the advantages of KMSNs@PMA@EB nanoparticles multidimensional enhancement of pesticide efficacy, persistence, and safety to parasitic wasps and has great potential to be used in pest control combining parasitoid and nanopesticides.