author(s)
Vanitha Shanmugam and Parthasarathy Seethapathy

abstract
The present paper presents research on the isolation of pathogen, pathogenicity test and standardization of culture media, susceptible stage of infection. The isolated fungal pathogen appeared as initially white in color and later turn into yellowish in color and the spores were spherical, oval and non septate. The pathogenicity test proved that artificially inoculated B. bassiana in healthy silk worms showed typical symptoms of white muscardine. The maximum growth B. bassiana has supported by SDA medium by recording the mycelial growth of 85.3 mm. The highly susceptible stage of silkworm for muscardine disease percent were the larvae inoculated more than 12 hours before moulting and six hours after moulting by recording 100 per cent mortality.