Larvicidal, ovicidal and repellent activities of Cymbopogan citratus Stapf (Graminae) essential oil against the filarial mosquito Culex quinquefasciatus (Say) (Diptera : Culicidae).

Essential oils extracted by steam distillation from Cymbopogan citratus were evaluated for larvicidal, ovicidal and repellent activities against the filarial mosquito Culex quinquefasciatus. The larval mortality was observed after 24 hours treatment. The LC(50) values calculated for the 2nd, 3rd and 4th larval instar were 144.54 +/- 2.3, 165.70 +/- 1.2 and 184.18 +/- 0.8 ppm respectively. Hundred percent ovicidal activity was observed at 300 ppm. Skin repellent test at 1.0, 2.5 and 5.0 mg/cm(2) concentration of C. citratus gave 100% protection up to 3.00, 4.00 and 5.00 hours respectively. The total percentage of protection of this essential oil was 49.64% at 1.0 mg/cm(2), 62.19% at 2.5 mg/cm(2) and 74.03% at 5.0 mg/cm(2) for 12 hours.