LAUSR

BACKGROUND Emamectin benzoate (EMB), a frequently used biopesticide, is poorly soluble in water, hard to wet the leaf surface, prone to degrade under sunshine and finally ready to lose bioactivity. Traditionally methods like organic solvents application, pH adjustment and photoprotectants addition either increase the economic and environmental costs or hardly reach the goal. We hypothesized that nanotechnology could improve the solubility, foliar affinity, photostability and the bioactivity of EMB. And this research was to prepare nano-EMB solid powder (nano-EMB-SP) and testify this hypothesis. RESULTS Nano-EMB-SP was prepared by self-emulsifying method combined with carrier solidification technique. The mean particle size and PDI of nano-EMB-SP were 14.64 nm and 0.24 respectively. SEM image showed EMB nanoparticles were mainly spherical or ellipsoidal in shape. Without organic solvent, the aqueous solubility of EMB in nano-EMB-SP was 4500 mg/L and is at least 14 folds of EMB soluble granule (EMB-SG), which is solubilized by pH adjustment. Excellent foliar affinity of EMB was achieved by nano-EMB-SP, which completely wet and penetrated the superhydrophobic surface of cabbage (Brassica oleracea L.) leaf. Without photoprotectants, up to 82 percent of EMB content can be kept from UV damage by nano-EMB-SP. The combined effects of excellent photostability and foliar affinity of nano-EMB-SP made the bioactivities of EMB nearly unchanged before and after UV radiation. CONCLUSION Nano-EMB-SP can eco-friendly and efficiently improve the solubility, foliar affinity, photostability and bioactivity of EMB. This research provides a good approach to improve the efficacy of poorly soluble and UV sensitive pesticides. This article is protected by copyright. All rights reserved.