A comparative study of the controllable release and insecticidal efficacy for two typical carrier methods on diamide insecticide delivery system

Abstract

Using nano/microcarriers of pesticides in sustainable pest management represents a promising strategy for enhancing pesticide efficiency while mitigating environmental harm. The reported pesticide loading methods include one-step self-assembly encapsulation and two-step absorption loading, but the controllable release and insecticidal efficacy of these two methods have been infrequently evaluated. Herein, the typical diamide insecticide cyantraniliprole (CTP) was employed as the model pesticide. A hydrogen bond-driven one-step self-assembly method and a chemical deposition method were utilized to fabricate highly dispersed polylactic acid (PLA) microspheres and calcium carbonate (CaCO₃) microspheres. The resulting CTP-loaded PLA microspheres (CTP-PLA MS) and CaCO₃ microspheres (CTP-CaCO₃ MS) both exhibited high adhesion, resistance to rain erosion, and insecticidal activity under laboratory conditions. However, the functional CTP-PLA MS demonstrated superior sustained pesticide release performance, higher pesticide loading capacity, and less application amount than that of CTP-CaCO₃ MS. At the same time, the acute toxicity of CTP-PLA MS exhibited slightly reduced acute toxicity to honeybees (Apis mellifera), signifying enhanced biocompatibility. Finally, the CTP-PLA MS maintained superior insecticidal efficacy than the normal CTP in controlling O. nubilalis at a low concentration. The present study represents a promising pesticide carrier as a highly efficient, eco-friendly agent for sustained management of O. nubilalis.