SUMMARYThe production of bulbiformin byBacillus subtilishas been observed on the seed coats, spermatosphere and rhizosphere of bacterized pigeon‐pea seeds sown in sterile and unsterile soils. The importance of different nutrients as a base for bacterization in enhancing the antibiotic production has been established. Maximum antibiotic activity was observed in the treatments where bacterization had been made in molasses solution supplemented with groundnut cake. The rate of antibiotic production reached a peak after 15–18 days. Relatively less antibiotic was synthesized under natural unsterile soil conditions.It is shown that the antibiotic produced as a result of bacterization becomes systemic in plant tissue and provides a protective zone around the roots of pigeon‐pea seedlings. Appreciable reduction in the incidence of pigeon‐pea wilt has been obtained through seed bacter