P12-08 : Isolation of spore-forming bacteria from a Fusarium wilt-suppressive soil and their utilization against the major tomato soilborne pathogens
1Tokyo University of Agriculture and Technology
Fusarium-wilt caused by Fusarium oxysporum f. sp. lycopersici is one of the major constraints in tomato production. Chemical fungicides and soil disinfection with fumigants are the main commercially available options for control of the disease. Chemical measures might adversely affect beneficial soil microorganisms and also pollute the environment. Therefore, controlling of Fusarium wilt with antagonistic microorganisms represents an effective alternative disease management strategy. In this study, 9 soils were evaluated for their susceptibility to tomato Fusarium-wilt pathogen. Three soils significantly suppressed the disease incidence. A total of 360 spore-forming bacteria were isolated from the surface-sterilized roots and rhizosphere soils of tomato seedlings grown in a disease-suppressive soil. Isolates were selected on the basis of in vitro antibiosis to the pathogen. Fifty out of 360 isolates inhibited both Fol and Forl. Thus, the selected isolates were evaluated to Fol through combinations of five isolates in a seed coating trial. Four out of 10 combinations significantly decreased the disease influence. Based on the results, 20 isolates were evaluated to Fol individually. Two out of 20 isolates significantly suppressed the disease incidence.