Abstract

Objective: To identity and evaluate mosquito larvicidal and repellent activity against the malarial mosquito Anopheles stephensi (A. stephensi) and filarial mosquito Culex quinquefasciatus (C. quinquefasciatus). Methods: The eggs and egg rafts of A. stephensi and C. quinquefasciatus were procured from National Centre for Communicable Diseases, Mettupalayam, Tamilnadu, India. Filter paper attached with eggs was dipped into a plastic tray containing 500 mL of dechlorinated water for 30-40 min, long enough to allow the eggs to hatch into larvae. Results: The larval mortality was observed for late fourth instar after 24-h treatment. The maximum activity of LC50 value was 0.051 mg/mL and 0.0514 mg/mL for A. stephensi and C. quinquefasciatus respectively in essential oil treated at minimum concentration. Skin repellent test at 1.0, 2.0, 3.0 and 4.0 mg/cm2 concentration of Rhizophora mucronata (R. mucronata) gave 100% protection up to 11 h. These results clearly revealed the potent larvicidal and repellent activity of R. mucronata essential oil. The present study was conducted to identify the chemical constituents with the GC-MS analysis in the most effective volatile oil of R. mucronata. Conclusions: The results have clearly demonstrated the possibility of transforming the potential natural products into commercial larval and repellent agent after being tested in different geo-climates and mosquito species.

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