SUPPRESSION OF GAEUMANNOMYCES-GRAMINIS VAR TRITICI IN MONTANA SOILS AND ITS TRANSFERABILITY BETWEEN SOILS

Three soils from different wheat growing areas of Montana were characterized as being conducive or suppressive to the take-all disease of wheat caused by the fungus Gaeumannomyces graminis var. tritici. Bozeman PF soil, where wheat was grown in rotation with green manure crops, exhibited conducive properties. Larslan 1 and Toston LS soils where wheat has been grown as a monoculture for more than 10 yr were suppressive to take-all. The transferability of this suppressiveness was established. However, the magnitude of the response differed between soils. In one case, a conducive soil had a suppressive factor against take-all which was not activated in its own soil, but which became active when transferred to a chemically and physically different soil.