Evaluation of Bitertanol and Thiabendazole Seed Treatment and PCNB Soil Treatment for Control of Dwarf Bunt of Wheat. J. A. Hoffmann, Research Plant Pathologist, USDA, ARS, Applied Statistics Department, Utah State University, Logan 84322. D. V. Sisson, Professor, Applied Statistics Department, Utah State University, Logan 84322. Plant Dis. 71:839-841. Accepted for publication 20 February 1987. 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, 1987. DOI: 10.1094/PD-71-0839.

Bitertanol and thiabendazole seed treatment (1.5 g a.i./kg) and PCNB soil treatment (2.67 kg a.i./ha) were compared for control of dwarf bunt in Nugaines and Wanser winter wheat seeded on four dates. PCNB applied to the soil surface in late fall was the most effective treatment and reduced dwarf bunt incidence 88–96% in both cultivars seeded on all four dates. Seed treatment with bitertanol was about twice as effectve as thiabendazole and reduced dwarf bunt to less than 5% in both cultivars seeded on 27 September and 11 October. Thiabendazole seed treatment provided control only in wheat seeded on 11 October. Both seed treatments reduced wheat yields. Dwarf bunt reduced yields by about 0.83% for each percentage of disease incidence.