Insecticidal Effects of Paullinia pinnata (L.) Extracts on Callopistria sp. (Noctuidae: Fern Caterpillar)

The increasing herbivory of Nephrolepis species by Callopistria floridensis larvae (fern caterpillars) threatens the ecological integrity of wetland habitats in Bayelsa State, Nigeria. This study evaluated the insecticidal potential of Paullinia pinnata (L.) foliage and fruit extracts against C. floridensis, alongside an assessment of the plant’s phytochemical composition. Foliage and fruit samples of P. pinnata were collected, air-dried, and extracted using aqueous and ethanol solvents following standard protocols. Quantitative phytochemical screening revealed that ethanol-based foliage extract contained the highest concentrations of alkaloids (1.091 mg/L), tannins (2.242 mg/L), glycosides (1.970 mg/L), saponins (2.260 mg/L), and phenols (0.810 mg/L), while the aqueous foliage extract showed the highest flavonoid content (1.846 mg/L). Laboratory bioassays were conducted using 720 larvae of C. floridensis in a randomized complete block design (RCBD). Extracts were applied at five concentrations (2.5 - 20 mg/L), and larval mortality was observed at 2.5, 5, 7.5, and 10 hours post-treatment. Results showed a dose and time dependent increase in larval mortality (p ≤ 0.05), with ethanol foliage extracts achieving 100 % mortality by 10 hours at concentrations ≥5 mg/L. The aqueous extracts also showed significant activity, though delayed and less potent at lower concentrations. Ethanol extracts of both foliage and fruits consistently outperformed aqueous counterparts across all time intervals, while the fruit extracts were comparatively less effective, especially the aqueous type. The control treatments consistently recorded <3% mortality throughout the time frame. These findings confirm that P. pinnata contains potent bioactive compounds and offers strong potential as a botanical pesticide for managing Callopistria sp. infestations, contributing to sustainable pest control in tropical agroecosystems.