Toxicity of essential oil vapours obtained from Achillea spp. to Sitophilus granarius (L.) and Tribolium confusum (Jacquelin du Val)

Essential oil vapours from Achillea biebersteinii, A. millefolium and A. wilhelmsii (Compositae) were tested for their toxicity against the adults of Sitophilus granarius (L.) and Tribolium. confusum. (Jacquelin du Val). Eessential oils were applied in 2, 4 and 8 mu l doses in desiccators with 4 1 capacity, corresponding to 0.5, 1 and 2 mu l/l air. Although desirable insecticidal activities against these pests were achieved with essential oils of the three plant species, the oil of A. wilhelmsii was found to be the most effective. in all plant species, higher doses or longer exposure periods were more effective against S. granarius and T confusum. One-hundred percent mortality was achieved only with 2 mu l/l air doses of the essential oils of A. biebersteinii and A. wilhelmsii against S. granarius. On the other hand, only the essential of A. biebersteinii killed 100% adult T confusum in the same dose. It can thus be concluded that essential oils from A. biebersteinii and A. wilhelmsii are potential control agents against S. granarius and T confusum in storage facilities.