Insecticidal effect of essential oil of Origanum acutidens against several stored product pests

Essential oil vapours from the plant species Origanum acutidens L. (Lamiaceae) were tested for their toxicities against the adults of Lasioderma serricorne F. (Coleoptera: Anobiidae) and Sitophilus granarius L. (Coleoptera: Curculionidae), and third instar larvae of Ephestia kuehniella Zell. (Lepidoptera: Pyralidae). The amounts of essential oil applied were 2, 4, 6 and 8 mu l in each of the desiccators with 4 L capacity, corresponding to 0.5, 1, 1.5 and 2 mu l/L air. The test essential oil achieved 100% mortality with a dose of 2 mu l/L air within 96 h in all life stages tested. In general, mortality increased with the doses of essential oil and exposure periods. Although the essential oil of O. acutidens was found to be effective against all test insect species, E. kuehniella, in general, was more sensitive against the oil than both S. granarius and L serricorne in all dose and exposure time variants. The results of the study suggest that essential oil from this plant has a potential as control agent against E. kuehniella, L. serricorne and S. granarius under storage conditions.