Comparative Study of Insecticidal Activity of Essential Oil 1, 8-Cineole and Linalool against Sitophilus oryzae

Eucalyptus essential oil is one of the most important essential oils which have fumigant toxicity againstinsects. 1, 8-Cineole is the most important compound of the genus Eucalyptus, and is largely responsible forits pesticide properties. This study was conducted to assess the fumigant toxicity potential of 1, 8-cineoleand linalool essential oils on Sitophilus oryzae (Coleoptera: Curculionidae). Bioassays were carried out at27±1 ºC and 60 ± 5% R. H. under dark condition adopting a complete randomized block design. Fiveconcentrations of essential oils were tested in four replications with 20 adult insect in each replication.Treated filter papers (4 × 5 cm), were placed at the bottom of 280 ml glass jars. Twenty adults 1-7 days oldwere placed in small plastic tubes with open ends covered with cloth mesh. The tubes were hung at thegeometrical centre of the glass jars, which were then sealed with air-tight lids. Mortality was recorded after24 hours. The results showed that 1, 8-cineole was more toxic than linalool. Estimates of LC50 values for 1,8-cineole and linalool were 34.89 and 308.03 μl/l air and LC95 respectively, and LC95 were evaluated 193and 2462.07 μl/l air respectively, that revealed higher susceptibility in S.oryzae to the 1, 8-cineole . Resultsshowed that the mortality was increased significantly as oil concentrations were increased and the oil isapplicable the management of population of stored product pest in storage

کلیدواژه ها:

Essential oils ، 1 ، 8-Cineole ، Linalool ، Sitophilus oryzae ، Insecticidal activity