Mustard aphid, Lipaphis erysimi (Kalt.), is the most serious insect-pest of rapeseed- mustard and responsible for causing the yield losses ranging from 35.4 to 96 percent depending upon weather condition. Entomopathogenic fungi are natural enemies of various pests and are considered to be valuable bio-control agents in sustainable crop management. In this study, laboratory evaluations were made to assess bio-control potentiality of few entomopathogenic fungi for mustard aphid management. Analysis of the virulence of 4 fungal strains against Mustard aphid was carried out in laboratory bioassays at 1 × 108 CFU ml-1 for 3 and 7 days. The pathogenicity study revealed two most efficient fungal strains Metarhizium anisopliae followed by Nomuraea releyi as bioagent with least incubation period against Mustard aphid. The FTIR spectrum of extracts for the fungal isolates such as Metarhizium anisopliae, Beauveria bassiana, Verticillium lecanii and Nomuraea releyi were analyzed. FTIR spectrum was blown up for the selected fungal strains to locate specific wavenumber cm-1 with regard to find out the specific stretch.