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Effect of Mineral Nutrition on Take-all of Wheat. E. M. Reis, Plant pathologist, Centro Nacional de Pesquisa de Trigo, Caixa Postal, 569, 99.100 Passo Fundo, RS, Brazil; R. J. Cook(2), and B. L. McNeal(3). (2)Research plant pathologist, Agricultural Research Service, U.S. Department of Agriculture, Pullman, WA 99164; (3)Professor, Agronomy and Soils, Washington State University, Pullman 99164. Phytopathology 72:224-229. Accepted for publication 22 April 1981. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1982. DOI: 10.1094/Phyto-72-224.

Take-all of wheat caused by Gaeumannomyces graminis var. tritici developed on significantly fewer roots, and plants had a lower disease severity index when phosphorus (P), potassium (K), and magnesium (Mg) were made available to the wheat roots in a silica sand rooting medium at twice, compared with one-half, the concentration in normal Hoagland’s solution. Calcium (Ca) and sulfur (S) had no significant effect on take-all either at half or twice the concentration in normal Hoagland’s solution. The increased P, K, and Mg also resulted in the greatest increase in root development compared with Ca and S, which had the least effect on numbers of roots. Increasing nitrogen (N, as nitrate) from half to twice Hoagland’s resulted in significantly more roots per plant, but disease severity on a given plant did not change significantly. Zinc (Zn) and copper (Cu) treatments each resulted in more roots and less take-all per plant when supplied either to roots or leaves compared with treatments where those nutrients were withheld completely. Manganese (Mn), and possibly iron (Fe), also had suppressive effects on take-all as the supply was increased when applied in the rooting medium but not when applied by foliage sprays. In the field, the addition of Zn and Zn plus Peach resulted in less take-all in wheat plots under irrigation at Lind, WA; and Zn, Cu, and a mixture of Zn, Cu, Mn, and Fe each reduced take-all of nonirrigated (rainfed) wheat in plots at Puyallup, WA. The reduction of disease in the field was significant (P = 0.05) only at low and moderate levels of disease intensity. The results indicate that certain macronutrients and micronutrients have the potential for limiting take-all, either by lessening susceptibility of the host tissues to the pathogen, promoting the formation of new roots, or by both mechanisms.

Additional keywords: Triticum aestivum, soilborne pathogens.