Sublethal effects of two entomopathogenic fungi species, Metarhizium anisopliae and Beauveria bassiana, on the cabbage aphid (Brevicoryne brassicae)

Abstract

We evaluated the sublethal (LC25) effects of the three native strains of two important entomopathogenic fungi (EPFs) species (Metarhizium anisopliae AB, M. anisopliae Iran 245, and Beauveria bassiana 106) on the cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae) which is among the most destructive pests of cole crops. Studies were carried out in controlled conditions providing 25 ± 2 °C, 60% ± 5% RH and a photoperiod of 16:8 h (L:D). The age-stage, two-sex life table method was used for data analysis. The results indicated that EPF treatments affected the population growth rate of the aphids by causing prolongation of the development time, decrease in survival rate, shortening of adult longevity, and decrease in reproduction. The intrinsic rate of increase (r) and the finite rate of increase (?) reflecting combined effects of all life history parameters were the highest in the control group and the lowest in M. anisopliae AB treatment. Similarly, the mean generation time was the shortest in the control treatment and the longest in M. anisopliae AB group. The overall results demonstrated that EPFs tested in this study could be considered an alternative option in the IPM programs against cabbage aphid, and M. anisopliae strain AB is the most promising EPF for further evaluation.