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

Three soils from different wheat growing areas of Montana were charact erized as being conducive or suppressive to the take-all disease of wh eat caused by the fungus Gaeumannomyces graminis var. tritici. Bozeman PF soil, where wheat was grown in rotation with green manure crops, e xhibited conducive properties. Larslan 1 and Toston LS soils where whe at has been grown as a monoculture for more than 10 yr were suppressiv e to take-all. The transferability of this suppressiveness was establi shed. However, the magnitude of the response differed between soils. I n 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.