Abstract
Basal rot of rakkyo (Allium chinense) is caused by Fusarium oxysporum f. sp. allii. Non-pathogenic strains of Fusarium moniliforme and Fusarium oxysporum were isolated from the healthy root tissues of rakkyo. Preinoculation treatment of rakkyo bulbs by dipping them in the bud-cell suspension of the non-pathogenic isolates reduced the disease incidence in the infested field. This method was more effective than soil drenching with a bud-cell suspension of isolates. However, the effect depended on the inoculum concentration. Preinoculation with a mixture of F. moniliforme and F. oxysporum led to a higher disease suppression than when the strains were used singly. The isolates of F. moniliforme and F. oxysporum were also non-pathogenic to other crops, viz., rice, tomato, eggplant, cucumber, melon, watermelon and radish.
