Mahdieh Saeidi - Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box ۱۴۱۱۵-۳۳۶, Tehran, Iran
Saeid Moharramipour - Department of Entomology, Faculty of Agriculture, Tarbiat Modares University, P. O. Box ۱۴۱۱۵-۳۳۶, Tehran, Iran

The essential oils of aerial parts of three medicinal plants Artemisia khorassanica Podl., Rosmarinus officinalis L. and Mentha longifolia L. were isolated by hydrodistillation and investigated for their toxicity and repellency against Tribolium confusum Jacquelin du Val. at ۲۷ ± ۱ ºC and ۶۰ ± ۵% RH in darkness. The mortality of the adults increased with concentration from ۱۸۵ to ۱۱۱۱ μl/l air and with exposure time from ۹ to ۲۴ h. A concentration of ۱۸۵ μl/l air and exposure time of ۲۴ h was sufficient to obtain nearly ۱۰۰% kill of the adults in all of the three essential oils tested. At the highest concentration (۱۱۱۱ μl/l air) R. officinalis oil caused ۱۵% mortality for an exposure time of ۶-h. whilst, the oil of A. khorassanica resulted in ۱% mortality at the same exposure time. The oil of A. khorassanica at ۱۱۱۱ μl/l air caused ۸۱% mortality for ۱۲-h exposure time. No significant differences were observed between the lethal time (LT۵۰) values at essential oil concentrations of ۷۴۱ and ۱۱۱۱ μl/l air. For ۲۴-h exposure time, the LC۵۰ values of A. khorassanica, R. officinalis and M. longifolia essential oils were estimated to be ۲۲.۴۵, ۲۲.۱۴ and ۳۹.۹۶ μl/l air respectively. Based on LC۵۰ values, adults of T. confusum showed similar susceptibility to the A. khorassanica and R. officinalis oils, but M. longifolia oil proved to be less toxic. In contrast to their low fumigant properties, the essential oil of M. longifolia had significantly higher repellency to T. confusum adults than did the other two.

Essential oil, fumigant toxicity, repellent, Artemisia khorassanica, Rosmarinus officinalis, Mentha longifolia, Tribolium confusum