Chloride Fertilizer Effects on Stripe Rust Development and Grain Yield of Winter Wheat. J. M. Scheyer, Graduate Assistant, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. N. W. Christensen, and R. L. Powelson. Associate Professor, Professor, Department of Soil Science, and Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. Plant Dis. 71:54-57. Accepted for publication 19 May 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0054.

Seven winter wheat cultivars grown in the field on an Aquultic Argixeroll (pH 5.5) were spring topdressed with (NH₄)₂SO₄ or NH₄Cl to determine the effect of chloride (Cl) on the progress of stripe rust disease. Choride rates of 0, 76, 152, and 304 kg ha^–1 were applied at a constant N rate of 120 kg ha^–1. Plots were inoculated with Puccinia striiformis, using a composite spore collection representing races common in the Willamette Valley of Oregon. Stripe rust severity was determined weekly, and disease progress curves were generated for each Cl treatment on the four cultivars developing the disease. Chloride reduced the apparent infection rate on Purplestraw, Yamhill, and Rew cultivars in one year but increased the apparent infection rate on Rew in another year. Results confirm that Cl-containing fertilizers can influence stripe rust development, but the effects are small and of questionable practical value. Chloride applied at 76 kg ha^–1 significantly increased grain yield by an average of 0.50 Mg ha^–1, possibly by reducing stress from take-all root rot caused by Gaeumannomyces graminis var. tritici.