Interaction between the entomopathogenic fungus, Beauveria bassiana (Ascomycota: Hypocreales) and the parasitoid wasp, Aphidius colemani Viereck (Hymenoptera: Braconidae)

The effect of the entomopathogenic fungus, Beauveria bassiana, on the biological characteristics of Aphidius colemani, a parasitoid of the green peach aphid, Myzus persicae, was studied under laboratory conditions. Third-instar nymphs of green peach aphid were infected with 5/3×105 conidia/mL of B. bassiana, which was determined to be the lethal concentration 50 dose. They were then offered to mated female parasitoids for 24 h at different intervals. Results showed that by prolonging the release intervals of parasitoids, the number of mummies and percent emergence of parasitoids were reduced. Moreover, production of male offspring increased in the F1 generation of parasitoids. The interference of B. bassiana with parasitoid development was also studied by first exposing the aphid hosts to the parasitoids for 24 h and subsequently spraying them with B. bassiana 24, 48, 72, and 96 h after exposure. Results showed that by prolonging fungal spraying intervals, the number of mummies and percent emergence of parasitoids were increased. It appeared that the best time for applying B. bassiana would be three to four days after parasitisation.