Isolation of Antibiotic-producing Bacteria Antagonistic to Fusarium oxysporum from Sesame-growing Soils and Evaluation of Their Antifungal Activity

For isolation of antibiotic-producing bacteria antagonistic to Fusarium oxysporum, a total of 327 microorganisms were screened from sesame-growing soils collected at various locations in Korea by the modified Herr's triple-agar-Iayer technique. Among the 36 bacterial isolates further screened by the dual culture test on tryptic soy agar, 10 were tested to show their antagonistic activity against 14 plant pathogenic fungi. Bacterial culture filtrates were shown either to inhibit some phytopathogenic fungal growth or to suppress F. oxysporum infection of sesame plants maintained in the green house. An isolate, B23, with the most prominent antagonistic activity was identified as Bacillus subtilis.