Eco-friendly chitosan base chlorantraniliprole nano-pesticides for effective control of Chilo suppressalis (Walker) through bidirectional transport

Abstract

Chilo suppressalis is a major pest that severely impacts rice production in China. However, the widespread use of insecticides has resulted in the development of resistance in C. suppressalis. The advancement of nanotechnology offers promising prospects for enhancing insecticide formulations and improving their efficacy. This study designed a pH-responsive release system composed of γ-PGA and chitosan (CS) loaded with chlorantraniliprole (CLAP). The synthesized CLAP-loaded nanoparticles had an average particle size of approximately 39.67 nm and a loading efficiency of 38.87%. Under a pH of 8.5, 64.4% of the pesticide was released within 120 hours. The CLAP@CS/γ-PGA formulation, after loading, exhibited a significant synergistic insecticidal effect, with bioassay results showing an 82.2% mortality rate of C. suppressalis six days post-treatment. Tests of metabolic genes and enzyme activities showed that CLAP@CS/γ-PGA rendered C. suppressalis more sensitive to insecticides by inhibiting the activities of P450 and by decreasing the expression of CYP9A68. CLAP@CS/γ-PGA also demonstrated favorable transport properties within C. suppressalis and rice plants, and due to the encapsulation by the nanoparticle carrier, it reduced toxicity to zebrafish. In summary, the system we investigated not only meets the needs of pest management but also enhances the utilization of pesticides.