The aim of the present study is to investigate the effect of three entomopathogenic fungi (EPF) (Beauveria bassiana, Cladosporium cladosporioides, and Verticillium alfalfae) on the aphid species, Metopolophium dirhodum (Walker) (Hemiptera: Aphididae). The selected EPF were isolated from the agricultural soil of the National Institute of Plant Protection (INPV) in Constantine, Algeria, and were tested against the aphid insects that were collected from the same area. The aphid species M. dirhodum were exposed to each fungal spore suspensions 10 7 conidia/ml for 10 s. Percent mortality was recorded at 1, 3, 5, and 7 days post treatment. Percentage mortalities, 7 days post treatment, were 95.83, 63.98, and 51.83% by B. bassiana, C. cladosporioides, and V. alfalfae, respectively. The higher protease activities were observed for isolate V. alfalfae with 95 U/ml, followed by B. bassiana with 38.26 U/ml, and finally C. cladosporioides with 35, 65 U/ml. The results presented in this study revealed that there was no relation between high alkaline protease activities and high virulence isolates.

Background Effects of the entomopathogenic fungi Beauveria bassiana, Verticillium alfalfae, and Trichoderma viride; secondary metabolites of MS1 (B. bassiana) and MS2 (V. alfalfae); and Dimethoate active substances on the aphid species, Aphis gossypii Glover (Hemiptera: Aphididae), were tested. Main body of the abstract Fungus isolates were prepared as 107 conidia ml−1 of spore suspensions and applied on the 2nd instar nymphs of A. gossypii. After the applications, evaluations were made on the 1st, 3rd, 5th, and 7th days by counting the live individuals. Obtained data were 100 and 93% mortality rate at MS1 (B. bassiana) and MS2 (V. alfalfae), and secondary metabolites were recorded in the 3rd day count results. On the 5th day counts, the highest mortality rates after secondary metabolites were statistically at the same group with B. bassiana, T. viride, and dimethoate. On the 7th day, counting results of all experiment groups were analyzed statistically and were found effective. Short conclusion Obtained results showed that the fungal secondary metabolites might be useful when utilized as a biocontrol agent against the aphids.

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