The future of this study was to prepare a natural pesticide which will not harm the environment and yet control pests. Neem gum nano formulation (NGNF), a novel biopesticide prepared from the Neem gum extract (Azadirachta indica) (NGE) was evaluated for its antifeedant, larvicidal and pupicidal activities against Helicoverpa armigera (Hub.) and Spodoptera litura (Fab.) at 100ppm. The NGNF showed significant (100%) antifeedant, larvicidal and pupicidal activities against H. armigera and S. litura. The LC50 values of 10.20, 12.49 and LC90 values of 32.68, 36.68ppm on H. armigera and S. litura, respectively at 100ppm. The NGNF treatments showed differences in the activities of detoxifying enzymes, carboxylesterases, glucosidases and glutathione S-transferases in the larval gut. Earthworm toxicity illustrated that 6.25ppm of chemical insecticides (cypermethrin) varied widely in their contact toxicities compared to 100ppm of NGNF and control in both contact filter paper and artificial soil test. The NGNF were characterized and confirmed by FTIR, XRD, SEM and EDX analysis. Ten compounds were identified from the Neem gum extract (NGE) by Gas Chromatography-Mass Spectrometry (GC-MS) analysis. The major compounds were fatty acids like Hexadecanoic acid, oleic acid, and ricinoleic acid. NGNF could be used as an agent to prepare novel bio-pesticides formulations.
Keywords: Detoxifying enzymes; GC–MS; Helicoverpa armigera; Larvicidal; NGNF; Spodoptera litura.
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