Abstract
The cell suspension (ca. 109 CFU/ml) of an antagonistic bacterium Serratia marcescens strain B2 was inoculated into the soil of the cucumber rhizosphere. The pathogen Rhizoctonia solani Kühn AG-4, which causes damping-off disease, was challenge-inoculated to the cucumber seedlings. Disease incidence with bacterial treatment was reduced to about 45% compared with that of the untreated control. The strain B2 survived in the soil of the rhizosphere under glasshouse conditions at ca. 106 to 107 CFU/g soil for 4 wk after application. Production of lytic enzyme chitinases and antibiotic prodigiosin by the strain B2 was enhanced under the presence of fungal hyphae. These results suggested that the strain B2 has a potential as an effective and long-lasting biological control agent to deal with cucumber damping-off disease.
