Larvicidal activity of Amyris balsamifera, Daucus carota and Pogostemon cablin essential oils and their components against Culex pipiens pallens

Larvicidal activities of Amyris balsamifera, Daucus carota, and Pogostemon cablin essential oils were tested against Culex pipiens pollens. All three oils showed 100% larvicidal activity against C. pipiens pollens at 0.1 mg/mL.. Among the tested oils, the larvicidal activity of D. carota oil was the strongest followed by P. cablin and A. balsamifera. Four active compounds such as beta-eudesmol, elemol, patchoulol, and carotol were isolated from the three oils by open column chromatography. These compounds showed >90% mortality against C. pipiens pallet's at 0.1 mg/mL. In acute toxicity testing of the water flea, Daphnia magna, P. cablin oil was the most toxic followed by A. balsamifera, and D. carota. Among the isolated compounds, carotol was the most toxic to water fleas. The residues of P. cablin, A. balsamifera, and D. carota in water were 67.8%, 59.5%, and 51.2% at 2 days after treatment, respectively. High concentrations of elemol and patchoulol were detected 2 days after treatment compared to those of beta-eudesmol and elemol. Whole oils and compounds tested were detected at <50% after 7 days in water. (C) Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society, 2012. Published by Elsevier B.V. All rights reserved.