Bio-based clothianidin-loaded solid dispersion using composite carriers to improve efficacy and reduce environmental toxicity.

Background: Neonicotinoids comprise one of the most extensively used classes of pesticides worldwide owing to their broad insecticidal spectrum and excellent biological performance. However, their toxicity to honeybee (Apis mellifera Linnaeus) and silkworm (Bombyx Mori) limits their further application. To address this issue, clothianidin as a model neonicotinoid was developed into a novel controlled-release formulation employing advantaged solid dispersion (SD) technology using composite carriers.

Results: In this research, the clothianidin-loaded SD was characterized using integrated methods to elucidate its formation mechanism, showing that clothianidin was embedded into the carrier homogeneously in small crystalline entities. The composite carriers, which are both renewable and environmentally friendly, can significantly prolong the release of clothianidin from seven to 25 days, compared with that of PEG 8000 as a single carrier. Based on the excellent controlled release profiles, it reduced the acute toxicity to A. mellifera and B. mori by 57.68- and 85.32-fold (respectively) compared with that of the conventional formulation. Furthermore, the SD displayed favorable efficacy and persistency against Asian citrus psyllid (Hemiptera: Psyllidae).

Conclusion: This novel strategy opens up a simple and powerful avenue for improving efficacy and promoting the environmental safety of neonicotinoid insecticides to be used in sustainable crop protection.