Purpose:To determine the larvicidal activity of the essential oil derived from Illicium difengpi B.N. Chang stem bark (Schisandraceae) and its major constituents against the larvae of Aedes aegypti L. Methods: Essential oil of I. difengpi stem bark was obtained by hydrodistillation and analyzed by gas chromatography (GC) and gas chromaotography-mas spectrometry (GC-MS). The activity of the essential oil and its major constituents was evaluated, using World Health Organization (WHO) procedures, against the fourth instar larvae of A. aegypti for 24 h, and larval mortalities recorded at essential oil/compound concentrations ranging from 6.0 -200 μg/mL. Results: A total of 36 components of the essential oil of I. difengpi were identified. The principal compounds are safrole (18.21 %), linalool (13.47 %), 1,8-cineole (12.84 %), and myristicin (8.06 %) followed by α-terpineol (4.77 %), β-pinene (4.45 %) and 4-terpineol (4.38 %). The essential oil exhibited larvicidal activity against A. aegypti with LC50 (median lethal concentration) of 31.68 μg/mL. The major constituents, myristicin, safrole,and 1, exhibited LC50 of 15.26, 39.45, and 72.18 μg/mL, respectively. Conclusion: The findings obtained indicate that the essential oil of I. difengpi and its major constituents have potentials for use in the control of A. aegypti larvae and may therefore be useful in the search for newer, safer and more effective natural compounds as larvicides.

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