author(s)
Heba Youssif El-Sayed Ibrahim and Merfat Kasem Gabr

abstract
Beauveria bassiana and four chemical insecticides were tested for their potentiality against Agrotis ipsilon 3rd instar larvae under laboratory conditions. In order to derive maximum benefits from applying both of entomopathogenic fungus and chemical insecticides in IPM program for controlling A. ipsilon larvae, compatibility of B. bassiana with the tested chemical insecticides were studied. It was found that, under laboratory conditions, except buprofezin which showed slight harmful effect on the fungus mycelial growth (51.73% growth inhibition), all other insecticides showed harmless effect. Also, the virulence of B. bassiana spores harvested from SDYA poisoned with LC90 of the tested insecticides was evaluated against A. ipsilon 3rd instar larvae under laboratory conditions. All treatments dramatically lost their virulence except those spores harvested from thiamethoxam-poisoned SDYA which slightly affected negatively. Moreover, it was found that all tested insecticides at sub-lethal doses (LC50) were compatible with B. bassiana under semi-field conditions. So, the combination of the tested insecticides at the sub-lethal doses with B. bassiana in IPM programs was recommended.