Synthesis of green Silica Nanoparticles (GSiO2NPs) utilizing aqueous extracts of plants and insecticidal activity evaluation against C. chinensis

Green-engineered nanoparticles are non-toxic, ecologically friendly, biocompatible, and biodegradable; they follow a single-step bioreduction process over chemically synthesized nanoparticles. Alkaloids, terpenoids, flavonoids, phenols, tannins, glycosides, and other phytoconstituents stabilize nanoparticles behaving as reducing or capping agents in green technology. In the present investigation, silica nanoparticles (SiO2NPs) using aqueous leaf extracts of Azadiracta indica (Az), Murraya koenigii (Mu), and Oscimum sanctum (Os) were synthesized. Using FESEM, EDX, Zeta potential, and XRD, the green synthesized nanoparticles (GSiO2NPs)—Az-SiO2NPs, Mu-SiO2NPs, and Os-SiO2NPs—were characterized. The findings revealed that all the GSiO2NPs are nanosized 20-50 nm (FESEM), exhibited strong signal peaks corresponding to silicon (EDX), falling values below -25 mV (Zeta Potential), and sharp peaks centered at 2Ѳ (XRD). Vigna angularis seeds were treated with several concentrations of GSiO2NPs (5 ppm, 20 ppm, 35 ppm, 50 ppm, and 70 ppm) and released 5 pairs of adult C. chinensis. Data was acquired after the first, third, fifth, seventh, and fourteenth days of exposure to determine adult mortality. The seed damage and weight loss were documented on the fourteenth day. The data was analyzed using two-way ANOVA and a critical difference test to determine the significance. Az-SiO2NPs outperformed Mu-SiO2NPs and Os-SiO2NPs in terms of greatest adult mortality and least amount of seed damage and weight loss.