Application of different sources of manganese sulfate decreases take-all (Gaeumannomyces graminis var. tritici) of wheat grown in a manganese deficient soil.

Two experiments tested the effectiveness of manganese (Mn) decreasing take-all of wheat. The first experiment was conducted under controlled environmental conditions. Mn sulfate was mixed through the soil at sowing or 2 weeks before, or applied to the seed or leaves, and manganese dioxide (Mn02) was mixed through the soil at sowing or 2 weeks before. Mixing manganese sulfate (MnS04) through the soil was the most effective treatment at decreasing take-all, followed by seed applied Mn. Mn02 and foliar applied Mn had little effect on take-all. All Mn treatments, except foliar Mn, completely eliminated Mn deficiency in the plants. In the second experiment, which was conducted in the field at a Mn deficient site, Mn sulfate and Mn02 were applied to the soil at sowing. MnS04 decreased take-all and increased grain yields in take-all inoculated plots nearly threefold, but increased yields only slightly in uninoculated plots. Mn02 was not effective in decreasing take-all or increasing grain yield. This is the first report of take-all infection being suppressed by MnS04 in the field. The results of these experiments support the hypothesis that Mn may be acting through the physiology of the wheat plant to decrease take-all.