Abstract
Essential oil was extracted from the leaves of Hyptis suaveolens by hydro-distillation. The Mosquitocidal activity, mosquito larvae (larvicidal) and mosquito repellency effect was carried- out using standard methods. Percentage yield of the essential oils was gotten as 0.05, for the larvicidal activity dose dependent mortality of the larvae was observed; there was low mortality rate at lower dosage and not significantly different from each other e.g. 6.25 and 12.50ppm had same LC 50 and LC 90 of 25.21 and 302.67 respectively, 25ppm had LC 50 and LC 90 of 9.58 and 352.46 respectively, while 50-1000ppm had LC 50 and LC 90 of 0.55 and 0.85 respectively. It was observed that the amount of air that enters and leaves the cage affect the rate at which mosquitoes were repelled. In a group of mosquitoes kept in a cage with all sides open (ASO) 65% of the mosquitoes were repelled within 30 minutes while for one side open (OSO) and all sides closed (ASC), 73% and 85% of the mosquitoes were repelled within the same time frame. In a second experiment, 100% of mosquitoes were repelled from the surface of rats with shaven skin where essential oil was applied. The essential oil also demonstrated dose dependent
mosquitocidal activity with LC 50 and LC 90 values of 6 and 21ppm respectively.
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