Green synthesis and larvicidal activity of ZnO nanoparticles against Lucilia sericata larvae using essential oil bio-reductants.

Lucilia sericata, a dipteran fly, causes myiasis by infesting living or necrotic tissues and transmits mycobacterial infections to livestock. Its potential resistance to common insecticides underscores the need for integrated pest management strategies and highlights the importance of biopesticides. In this context, larvicidal effects of Citrus sinensis, Cymbopogon flexuosus, Achillea millefolium, Origanum onites, Salvia fruticosa, and Mentha piperita essential oils and biocapsulated ZnO nanoparticles were investigated to control Lucilia sericata vectors. Synthesized ZnO nanoparticles were characterized using UV-Vis spectrophotometry, SEM and EDX techniques. By analytical characterization, sizes of nanoparticles loaded with Cymbopogon flexuosus and Citrus sinensis essential oils were 112 and 230, respectively, and SEM analysis confirmed monoclinic and hexagonal crystallites. The larvicidal effects of oils and nanoparticles were determined at various concentrations (0.5, 1, 5, 10 and 20 µg/ml) and all oils except Origanum onites showed high larvicidal effects and a linear increase in % mortality was observed with increasing concentration. To understand molecular mechanisms of larvicidal effect of oils on Lucilia sericata larvae, in silico analyses revealed that the highest antagonistic activity against the cytochrome P450 6A1-like protein of the species homology modeled was mediated by carvone and vertonal compounds, and predictions of ADMET properties revealed the properties of volatile bioactive components as a low toxicity alternative to temefos, a currently used larvicide. This research demonstrates the usability of the six essential oils and biosynthesized nanoparticles as highly effective, natural fly vectors and control pesticides.