Construction of Lambda-Cyhalothrin Nano-Delivery System with a High Loading Content and Controlled-Release Property.

Traditional pesticide formulations are limited by large organic solvent consumption, poor dispersibility, and poor foliar adhesion, resulting in low effective pesticides utilization and environmental pollution. To prolong the foliar pesticide retention and release time, a high lambda-cyhalothrin (LC)-loaded nano-delivery system was constructed, using polylactic acid (PLA) as a carrier through a solvent evaporation method. The obtained results showed that the stabilizer concentration, water⁻oil ratio, and carrier content exert a major influence on the LC loading, particle size, and size distribution. The prepared LC/PLA nanoparticles have a uniform spherical shape with a smooth surface. The size of the nanoparticles was less than 200 nm, and the LC loading capacity reached up to 46.6 wt.%, with a high encapsulation efficiency (exceeding 90%). Adjustment of the shear and ultrasonic time changed the size of the nanoparticles. Significant differences were found in the sustained release properties of LC/PLA nanoparticles with different LC loadings. The foliage adhesion of the LC nano-delivery system far exceeded that of the commercial LC formulation due to a low surface tension and a low contact angle, this foliage adhesion would greatly help to improve pesticide utilization.