Effect of Combination of Gamma Radiation and Essential Oil from Perovskia atriplicifolia on Mortality of Tribolium castaneum

In an attempt to find a natural and inexpensive method to control the stored-product pests, the effect of combination of gamma radiation and essential oil from Perovskia atriplicifolia (Benth) on the adults of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) was investigated. Experiments were carried out at 27±1°C and 65±5% R. H. under dark condition. Two experimental regimes were designed: 1) irradiation of fumigated adults 2)fumigation of irradiated adults. In combination experiments, mortality was assessed 14 days after the first treatment. The results showed significant synergistic effect of gamma radiation with essential oil on adults of T. castaneum (1-7 days old). Gamma irradiation at dosage 100Gy, alone caused 12.5% mortality on T. castaneum but when these irradiated insects were treated by 7.66 µl/l air of P. atriplicifolia oil 7 days after irradiation, (caused 6.25% mortality alone) mortality percent reached 32.5%. These results provide the basis for successful use of gamma radiation in the presence of the essential oil for management of T. castaneum.