Sublethal Effects of Some Entomopathogenic Fungi Isolates on Growth, Reproduction and Life Table Parameters of Brevicoryne brassicae L. (Hemiptera: Aphididae)

The cabbage aphid(CA), Brevicoryne brassicae L. (Hem.: Aphididae) is an important pest of brassicaceae family plants. In recent decades, biological control and use of entomopathogenic fungi (EPF) have been developed as an alternative or supplement of chemical pesticides to control aphids. Evaluation of the sublethal effects of pathogenic agents, such as EPF, is as important as mortality itself. Therefore, in this study, sublethal (LC25) effects of EPFs, Acremonium sclerotigenum, Lecanicillium muscarium, Beauveria bassiana, Paecilomyces variotii and Simplicillium sp., were studied on development, reproduction and life table parameters of the cabbage aphid under laboratory conditions. Among the tested isolates, the highest LC50 value was 2.57×103 conidia ml-1 in L. muscarium. The fungal treatment significantly (P<0. 05) reduced developmental rate, life span and fecundity of CA in comparison with control. The rm values in treatments of A. sclerotigenum, L. muscarium, B. bassiana, P. variotii  and Simplicillium sp., were 0.225±0.009, 0.219±0.011, 0.246±0.008, 0.254±0.004 and 0.215±0.008 day-1, respectively, which were significantly reduced in comparison with control (0.332±0.008 day-1). Results of peresent study showed that, A. sclerotigenum, L. muscarium and B. bassiana had greats effect on fertility, longevity, and life table parameters od CA and can be used as an effective microbial agent in integrated pest management of this pest if the results can be repeated in the field condition.