Optimization and characterization of pyraclostrobin nanoemulsion for pesticide delivery: Improving activity, reducing toxicity, and protecting ecological environment

Abstract

Nanoemulsion provides an effective way for the efficient, safe, and environmentally friendly use of pesticides. In this study, the influence of different type emulsifiers on the formation and stability of nanoemulsion were tested and an optimal pyraclostrobin nanoemulsion with long-term stability was obtained. Pyraclostrobin (2.5 %), #602 (phenylethyl phenol polyoxyethylene ether, 6 %), and #600 P (tristyryl- phenol polyoxyethylene ether phosphate, 2 %) were dissolved in methyl benzoate (2.5 %) and co-emulsifier ethanol (20 %) with deionized water replenished to 100 %. Compared with microemulsion (ME), the nanoemulsion using a lower dosage of emulsifier kept the system stable for a long time, reducing pollution of the environment. Compared with the commercial ME and suspension concentrate (SC), the nanoemulsion had a lower contact angle and surface tension, and higher maximum retention. In addition, adding 0.01 % AEO-3 (dodecyl alcohol polyol ethylene ether) to the dilution of nanoemulsion can significantly improve the target deposition of the nanoemulsion and improve the utilization rate of the pesticide. Besides, the use of methyl benzoate, an environmentally friendly solvent, resulted in the nanoemulsion with high bactericidal activity and low acute toxicity to zebrafish, thus reducing the environmental pollution of such chemicals.