There are many factors that influence the success of silk production. Bacterial
flacherrie considered the most important factor. Antibiotics showed promising results
for controlling of silkworm diseases and to improve the production of silk and
harvesting superior crop. The effect of antibiotic (Gentamicin) upon the infection with
bacterial flacherrie was discussed. Gentamicin as a cheap antibiotic in Egypt can be
used easily by trainees and farmers. It was found that Gentamicin significantly
increases the effective rate of rearing (ERR %) and larval weight (97.333% and
2.631gm, respectively). Single female and male cocoon weights (1.400 gm and 1.068
gm, respectively) and male cocoon shell ratio (22.708%) were significantly increased
under the effect of antibiotic treatment comparing with control. Polymorphism among
the tested haemolymphal samples were investigated using SDS-PAGE
electrophoresis. A variation was detected in the protein banding pattern with
considerable polymorphism (88.2 %), with the appearance of 2 monomorphic bands,
12 polymorphic and 3 unique bands.