To evaluate the larvicidal activity of essential oils derived from two essential plants and / or gamma irradiation against early fourth instar larvae of the greater wax moth (GWM), Galleria mellonella L. was investigated. Methods: The oil of two plants were tested namely; Marjoram, Origanum majorana and Lemon Grass, Cymbopogon proximus were tested. To evaluate the relative efficacies of these materials as alternative control agent against GWM. The two essential oils were evaluated further for the determination of their LC10, LC50 and LC90 values based on Probit analysis, five of gamma irradiation doses (100,150,200,250 and 300 Gy) and the combined effect of them and essential oil were tested. Results: Comparing the estimated LC10, LC50, LC90 values of present investigation of mentioned essential oils indicated that essential oils of Origanum majorana is more toxic to G. mellonella than the other essential oil of Cymbopogon proximus, then were selected in combined with the dose of 100 Gy in the shared experience. It also found that the percentage of pupation, emergence and sex ratio decreased with increasing concentration of both extracts -The lack of the number of eggs and the percentage of hatched eggs increase with the increase the radiation dose used from 100 Gy to 300 Gy -Also found that the percentage of larval mortality increases in the case of combined treatment of radiation and aromatic oils of the two plants than in the case of both of them solo. The percentages of pupation and emergence less in the case of combined treatment, but increased in the case of sex ratio Conclusion: it can be concluded that the insects varied in their susceptibility to various essential oils that probably referring to insecticidal ability of their active constituents |
