The bacterium B. subtilis isolated from the eggs of the silkworm was grown in nutrient broth and used as inoculums. About 600 freshly molted third instar larvae were starved for 6-8 h and divided into three groups A, B and C each containing 200 larvae. The inoculums of 1.0×〖10〗^6 CFU and 4.0 ×〖10〗^6 CFU per larvae of B. subtilis, smeared on a 1 cm2 piece of mulberry leaves, and fed to larvae of groups A and B, respectively. Larvae of group C were fed with
1 cm 2 piece of mulberry leaf smeared with sterile nutrient broth and used as a control.
The larvae, that consumed entire piece of leaves, were separated and reared on fresh mulberry leaves. Feeding, cleaning and sanitation schedule was followed as described by Krishnaswami13 up to cocoon spinning. The data on development and mortality were recorded. Survived male and female moths from inoculated groups, A and B were self crossed and allowed to oviposit the eggs. These eggs were tested for persistence of B. subtilis.