Difenoconazole Seed Treatment for Control of Dwarf Bunt of Winter Wheat. J. W. Sitton, Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow 83843. R. F. Line, J. T. Waldher, and B. J. Goates. Agricultural Research Service (ARS), U.S. Department of Agriculture (USDA), Pullman, WA 99164-6430; Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow 83843; and ARS, USDA, National Small Grains Germplasm Research Facility, Aberdeen, ID 83210. Plant Dis. 77:1148-1151. Accepted for publication 13 July 1993. 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, 1993. DOI: 10.1094/PD-77-1148.

We evaluated difenoconazole (Dividend 3FS), thiabendazole (Mertect LSP), triadimenol (Baytan 30F), and carboxin plus thiram (Vitavax 200) as seed treatments for control of dwarf bunt (caused by Tilletia controversa) on the susceptible winter wheat (Triticum aestivum) cultivars Nugaines and Hatton. Seed was planted at various dates during the fall of 1990 and 1991 at Logan, UT; Kalispell, MT; Pullman, WA; and Cavendish, ID. Dwarf bunt was most severe on plants that had developed to the two- to five-leaf stage in late fall before snowfall. Difenoconazole at 0.12 g a.i./kg provided complete control at all locations when wheat was seeded at intermediate and late dates. A low incidence of dwarf bunt developed when seed treated with difenoconazole was planted at early dates at some locations or when difenoconazole was applied at 0.06 g a.i./kg. The other fungicides tested did not provide adequate control.

Keyword(s): TCK smut.