Insecticidal effects of essential plant oils against Ephestia kuehnielia (Zell.), Lasioderma serricome (F.) and Sitophilus granarius (L.)

Essential oil vapours from the plant species Micromeria fruticosa (L.), Nepata racemosa L. and Origanum vulgare L. (Lamiaceae) were tested for their toxicities against the adults of Lasioderme serricorne (F.) (Coleoptera: Anobiidae) and Sitophilus granarius (L.) (Coleoptera: Curculionidae), and larvae (third instar) of Ephestia kuehniella (Zell.) (Lepidoptera: Pyralidae). The amounts of essential oils applied were 2, 4, 6 and 8 mu l in each of the desiccators with 4 1 capacity, corresponding to 0.5, 1, 1.5 and 2 mu l/l air. In E. kuehniella, complete kill could be achieved with the essential oils of all plant species in 8 mu l/l air after 120 h. Generally, mortality increased as the doses of essential oils and exposure period increased. Although desirable insecticidal activities against these pests were achieved with essential oils of all three plant species, the oil of O. vulgare was found to be the most effective against E kuehniella and S. granarius. On the other hand, the oil of N. racemosa was found to be the most effective against L. serricorne. The results of the study suggest that essential oils from these three plants have a potential as control agents against E kuehniella, L. serricorne and S. granarius under storage conditions.