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Disease Control and Pest Management

Control of Pythium Blight on Penncross Bentgrass with Pyroxychlor. P. L. Sanders, Research Assistant, Department of Plant Pathology, The Pennsylvania State University, University Park 16802; C. G. Warren(2), and H. Cole, Jr.(3). (2)(3)Research Aide, and Professor, respectively, Department of Plant Pathology, The Pennsylvania State University, University Park 16802. Phytopathology 66:1033-1037. Accepted for publication 18 February 1976. Copyright © 1976 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-66-1033.

The efficacy of the experimental systemic fungicide, pyroxychlor (Nurelle^®), was tested in vitro against species of Pythium, and in the greenhouse and field against Pythium blight on Penncross creeping bentgrass (Agrostis palustris). In vitro toxicity against 17 species of Pythium was variable. Field and greenhouse experiments indicate that the chemical was immediately effective against Pythium foliar blight, regardless of the method of application. Residual activity was significantly affected by application technique. Foliar sprays, not watered-in, provided control for less than 7 days, watered-in foliar sprays were effective for up to 21 days, and drenches exhibited the longest residual activity. When the experiment was terminated at 35 days post-treatment, the drench treatments significantly suppressed disease at all treatment rates.