Abstract

Objective: To determine the intrinsic toxicity of hexane, ethyl acetate and methanol crude extracts of Ageratum houstonianum leaves against adult Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus mosquitoes. Methods: Bioassay was performed in 2-day-old laboratory reared unfed adult female mosquitoes by topical application at concentrations of 0.01, 0.05, 0.10, 0.25 and 0.50 毺 g/mg female adult mosquito. Results: Aedes aegypti was found to be more susceptible to ethyl acetate and hexane extracts with LD 50 value of 0.10 毺 g/mg, and both Anopheles stephensi and Culex quinquefasciatus were susceptible to methanol extract with LD50 values of 0.12 毺 g/mg female adult mosquito. Conclusions: The results show promising adulticidal activity on topical application and further studies followed by in-depth laboratory and field bioassays are needed to screen, isolate and purify bioactive phytochemical constituents or compounds.

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