Preparation and characterization of emamectin benzoate nanoformulations based on colloidal delivery systems and use in controlling Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Colloidal delivery systems have been widely used as carriers for controlled delivery of pesticides to improve the efficacy and photostability of natural and semi-synthetic pesticides. In this study, we have synthesized emamectin benzoate nanoformulations (EB + NFs) depending on polymeric nanocapsules (PNC) and two types of the nanosilica, mesoporous nanosilica (MCM-48) and silicon dioxide nanoparticles (SNPs) as carriers for the emamectin benzoate (EB). The fabricated nanoformulations were characterized by using X-ray diffraction analysis, Fourier transform infrared spectroscopy, particle size, zeta potential, morphology, absolute recovery (AR), entrapment efficiency (EE), UV stability and release kinetics. The obtained results showed that the carriers had a remarkable loading ability for EB and improved the EB photostability. The EE% of nanoformulations were 92.84%, 87.45% and 71.19% for emamectin benzoate polymeric nanocapsules (EB + PNC), emamectin benzoate SNPs (EB + SNPs) and emamectin benzoate MCM-48 (EB + MCM-48) respectively. The insecticidal activity of EB + NFs against Plutella xylostella showed that the EB + SNPs was more effective than other EB + NFs and EB alone. The LC50 values were 0.18, 4.03, 8.49 and 11.06 mg L-1 for EB + SNPs, EB + MCM-48, EB + PNC and EB respectively. The obtained results suggest the colloidal delivery systems that used in this study could improve the efficacy and photostability for EB, and they are able to overcome the disadvantage of the natural and semi-synthetic pesticides such as environmental sensitivity and to increase the efficacy of pesticides, which eventually leads to reduce the dosage of pesticides needed, reducing the number of applications required in comparison to conventional formulations.