Six food grains were evaluated for their suitability as principal dietary ingredient in the mass production of entomopathogenic fungus Nomuraea rileyi during 1996-9? at the Department of Agricultural Entomology, University of Agricultural Sciences, Dharwad. Crushed sorghum and rice grains with one per cent yeast extract proved as the most favourable food media for the faster as well as higher conidial production over four other grains tested. Maize was the next best that performed at par with rice grain in enhancing the productivity of fungus on 10th day of inoculation, Bajra, ragi and wheat did seem to be favourable food media for fungal multiplication. Nature of food grain also influenced the quality parameter of entomopathogenic fungus. LC50 value of the fungus multiplied on sorghum to the Spodoptera litura larvae was lowest (5.425 x 10 6 Conidia /1)followed by rice (5.943 x 10 6 ) and least in wheat (7.175 x 10 6) Altered pathogenicity of the fungus by the dietary Ingredient led to increased requirement of conidial load by 9,55, 24.23 and 32.5 per cent in the case of rice, ragi and wheat, respectively over sorghum to induce mortality in 50 per cent of the test insect.