Effect of culex pipiens against marjoram and bitter orange andchemical constituents

摘要

In this study; the two oils were analyzed by GC/MS. About 20 and 32 volatile compounds were identified from the volatile oils of O. majorana and C. aurantium respectively. Terpinen-4 -ol and terpinene were the major isolated constituents of O. majorana, while limonene and 2-methyl-5-(1 -methyl efhenyle)-2-cyclohexene-1 -one were the maj or compounds of C. aurantium oil. Larvicidal activity of marjoram {Origanum majorana), (family: Verbenaceae) and bitter orange (Citrus aurantium), (family: Rutaceae)volatile oils were tested against the early fourth instar larvae of Culex pipiens. The larval mortality was observed after 24 hours of exposure. Both of the two oils showed high larvicidal effects; however, the highest larval mortality was found in the treatment with marjoram volatile oil. The LC50 values are 188.5 ppm and 251.4 ppm for marjoram and bitter orange respectively.