Larvicidal Activity of Green Synthesized Silver Nanoparticles and Chitosan Nanoparticles Encapsulated Aloe vera Gel Extract against Musca domestica (Diptera: Muscidae)

Background: There is a worldwide interest in metal nanoparticles synthesized by various chemical reactions for use in biomedical applications. These processes exhibit a broad range of toxicity in non-target organisms. To avoid chemical toxicity, green synthesis of metal nanoparticles is proposed as a cost-effective and eco-friendly alternative. Aloe vera (A. vera) leaf extract is a medicinal agent with multiple properties, including antibacterial effects. Its constituents include lignin, pectin and hemicellulose, which can be used in the reduction of silver ions to produce silver nanoparticles (AgNPs). Objective: The study aimed at the use of naturally occurring compounds as a reducing and stabilizing agent for the biosynthesis of nanoparticles and investigation of the insecticidal activity of these compounds against Musca domestica (M. domestica) larvae. Methods: Phytochemical analysis of A. vera gel extract was done and the phytochemical components were identified by Gas Chromatography–Mass Spectrometry (GC-MS) analysis. AgNPs and encapsulated Chitosan Nanoparticles (CsNPs) were prepared by an eco-friendly method using A. vera gel extract as a reducing and stabilizing agent. A. vera-AgNPs and A. vera encapsulated CsNPs were characterized using Ultraviolet-visible spectrophotometer (UV–vis spectrum), Transmission Electron Microscopy (TEM), Fourier-Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). Then the insecticidal activity of these compounds was investigated against late second instar larvae of the house fly. Results: The most active ingredients identified by GC-MS analysis were Terpene and Sesquiterpene hydrocarbons. The synthesized AgNPs were spherical with an average size of about 12-75 nm, as revealed by TEM. While encapsulated CsNPs ranged between 34-75 nm and the shape seemed spherical with dark parts confirming the encapsulated plant extract. FTIR and XRD results confirmed the successful encapsulation of the gel extract within the chitosan nanoparticles. Results proved the insecticidal potential of the tested compounds against M. domestica larvae, and the relative potency of encapsulated CsNPs was nearly 148.51 times more potent than A. vera crude extract whereas AgNPs was nearly 40.65 times more potent than A. vera crude extract. Furthermore, a prolongation of larval duration and reduction in the percentage pupation and adult emergence were observed. Conclusion: Overall, green-synthesized silver and chitosan nanoparticles have the potential for application as a biopesticide for house fly population control through the use of a safer and costeffective approach. © 2022 Bentham Science Publishers.