Abstract

Objective: To determine chemical composition and mosquito larvicidal activity of essential oil from dried leaves of Persea americana against Culex quinquefasciatus. Methods: About 20 larvae in each group were used for larvicidal assays. The mortality, relative growth index, larval and pupal duration and viability were estimated. The essential oil was analyzed by solid phase microextraction using gas chromatography coupled to mass spectrometry. Results: The most abundant compounds were estragole (61.86%), sabinene (15.16%) and 1R-α-pinene (14.25%). The essential oil inhibited mosquito larvae growth up to 26.73% [relative growth index (RGI) = 0.74)] and 16.83% (RGI = 0.84) at 800 and 50 mg/L respectively, while the untreated control and group treated with polysorbate 20 showed the RGI of 1.01. The viability of larvae to pupae decreased 53.75% when used 800 mg/L essential oil causing prolongation of development of 14.14 days, while the control had durability in its development of 12 days. In the pupae-adult phase, when used 800 and 50 mg/L of essential oil, 22.36% and 21.81% adults were formed, and there was prolongation of 15.88 days and delay of 13.62 days respectively; however the control showed duration of 14.63 days. Mortality at the end of the experiment was recorded as 57.50% with treatment of 800 mg/L and gradually decreased to 40% with treatment of 50 mg/L essential oil. Conclusions: The study demonstrated that the larvicidal activity of essential oil of Mexican avocado inhibited the normal growth and development of mosquito larvae, prolonged larval and pupal duration.

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