SUPPRESSION OF CLUBROOT FORMATION IN CHINESE-CABBAGE BY THE ROOT ENDOPHYTIC FUNGUS, HETEROCONIUM-CHAETOSPIRA

Root-colonizing fungi were isolated from a total of 663 root segments of Chinese cabbage plants grown in soils collected from wheat, rape, C hinese cabbage, and napier grass fields. Most of the 322 isolates were from the wheat field soil and comprised 18 genera and two septate fun gal groups. Hyaline and dark septate fungi accounted for approximately half the isolates from the wheat field soil. Sixteen isolates almost completely suppressed clubroot in sterile soil. Amongst these 16 isola tes, two from Heteroconium chaetospira were also effective in nonsteri le soil. Chinese cabbage seedlings from seed treated with these two is olates appeared healthy, and inoculation with one isolate promoted gro wth. Hyphae of the fungus covered the root surface and extensively col onized the inner cortical tissues.