Biodegradable Poly(ε‐Caprolactone) Nanoparticles for Controlled Release of Malathion: Enhanced Bioefficacy and Reduced Phytotoxicity

The toxicity of pesticides can be minimized by encapsulating them in a controlled release system. Poly (ɛ‐caprolactone) nanoparticles (PCL NPs) loaded with malathion were synthesized, characterized, and evaluated for the controlled release and bioefficacy against silverleaf whitefly. Microscopy data showed that the pesticide‐loaded PCL NPs were spherical in shape with a size of 100 nm. Encapsulation efficiency and loading percentage‐based optimization was carried out, and NPs with maximum encapsulation efficiency (14.92%) and loading percentage (99.5%) were selected for further experiments. In vitro release observations indicate the sustained release of pesticide occurred for 11 days following the non‐Fickian (anomalous) diffusion ( n = 0.68) driven by diffusion and swelling of the polymer. Bioefficacy observations over 15 days showed that PCL NPs encapsulated malathion (PCL‐M100, PCL‐M150, PCL‐M200) and free malathion (M200) effectively reduced approximately 96.92% of the whitefly population as compared to control, which concludes that even in small doses, PCL NPs encapsulated malathion (PCL‐M100) was as effective as the recommended doses (M200). PCL NPs encapsulated malathion showed significantly less phytotoxic effect even at twice the recommended doses (PCL‐M300 and PCL‐M400) as compared to the same doses of free malathion. The results showed that leaf injury was lowest at PCL‐M50 (21.66%) while highest at M400 (94.66%), exhibiting the protective aspect of nano‐encapsulation. The results conclude that loading pesticides in PCL NPs is a promising method for effective pest control at reduced doses while reducing phytotoxicity, thus making it a sustainable and safer tool for the delivery of pesticides that could reduce damage to the environment.