Antagonistic effects of Bacillus and Peseudomonas isolates on Phytophthora capsici the causal agent of pepper damping - off

The causal organism was isolated from rotted crown of pepper and was identified as Phytophthora capsici. In this study, 151 bacterial isolates were collected from various plant rhizospheres, 37 isolates belonging to fluorescent Pseudomonads and gramp ositive bacteria showed antagonistic effect on P. capsiciamong these antagonists, six were studied for their inhibitory effect against pepper damping–off. Baesd on biochemical, physiological and morphological tests, isolates D and 1083 were as Bacillus subtilis. The isolates 1083 and D produced antibiotic as well as volatile metabolites that inhibited mycelial growth of P. capsici in vitro. Isolates 1083 on king B medium produced siderophore, while isolate D did not produce siderophor at different FeCl3 concentrations. B. subtilis isolates prevented the mycelial growth through antibiotic and volatile metabolite Production. Among antagonistic isolates, only D and 1083 could produce hydrogen cyanid.