Extraction, Phytochemical Analysis, GC-MS Characterization and Larvicidal Activities of Leaf Extracts of Leucas aspera and Xanthium strumarium on Spodoptera Larva

The indiscriminate use of synthetic insecticides in agriculture has led to ecological imbalance and resistance in pests like Spodoptera species. The present study investigates the extraction, phytochemical composition, characterization and larvicidal activities of leaf extracts of Leucas aspera and Xanthium strumarium against Spodoptera larvae, a major agricultural pest. Aqueous and ethanol extracts were prepared from fresh leaves using Soxhlet extraction. Preliminary phytochemical screening revealed the presence of bioactive compounds such as alkaloids, flavonoids, tannins, saponins and terpenoids. Characterization of the extracts was carried out using Gas Chromatography–Mass Spectroscopy (GC-MS) and Fourier Transform Infrared Spectroscopy (FT-IR) to identify functional groups associated with insecticidal activity. Larvicidal bioassays were conducted using two concentrations (50 and 100 μg) under laboratory conditions and both extracts demonstrated significant dose-dependent mortality of Spodoptera larvae. Among the two, Xanthium strumarium extract showed higher larvicidal potential. These findings suggest that Leucas aspera and Xanthium strumarium leaf extracts possess potent phytochemicals with promising biocontrol potential and can be considered as eco-friendly alternatives to synthetic pesticides in integrated pest management (IPM) programs.