Lethal and sublethal effects of Metarhizium anisoplinae on fertility life table parameters of Brevicoryne brassicae in laboratory conditions

The cabbage aphid, Brevicoryne brassicae (L.), is a major pest of cruciferous crops all over the world that causes a considerable damage on different products by direct sap feeding and transmission of pathogenic viruses. Use of chemical pesticides is the most common control method of this pest but the adverse effects of these pesticides have shifted considerations to other environmental-friendly agents. In this study, the virulence of two isolates (DEMI001 and V245) of the fungus, Metarhizium anisopliae (Metch.) Sorokin was investigated against the adults of cabbage aphid in laboratory conditions. Adult aphids were treated with (103-107 conidia/ml) concentrations of fungus. Moreover, life table parameters of aphid were evaluated when treated with sub-lethal (LC30) concentration of the effective isolate, DEMI001. Results showed that the adults of cabbage aphid were completely sensitive to the isolates of fungus. LC50 values was scored 1.5×105 and 2.3×106 conidia/ml respectively for DEMI001 and V245 isolates. The shortest time needed for the mortality of 50% of the population was 6.67 days belonging to DEMI001 isolate at 107 conidia/ml concentration. Moreover, results showed that a sub-lethal (LC30) concentration of DEMI001 isolate, had significant effect on fertility of treated aphids. The values of rm and λ parameters were 0.28 female/female/day and 1.32 female/day, respectively. Our results showed that M. anisopliae can be used as an effective biocontrol agent in cabbage aphid control.