The pathogenic effect was observed in the form of 64 -77% mortality during larval and pupal stages. The prevalence of pathogenic bacterium in the progeny eggs, laid by infected females confirmed that the bacteria inoculated to the parent was transmitted into progeny eggs. The results indicated that isolated bacterium as B. subtilis is pathogenic to B. mori causing 64-77% mortality during larval and pupa stages. The adults those survived infections, laid infected eggs evidence the sequence homology of B. subtilis isolated from infected parents and their progeny eggs. Thus this is the first report on transovarial transmission of a Bacillus sp. in insects.