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Ecology and Epidemiology

Effects of Ozone on Infection of Soybean by Pseudomonas glycinea. J. A. Laurence, Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, Present address: Boyce Thompson Institute for Plant Research, 1086 North Broadway, Yonkers, NY 10701; F. A. Wood, Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108, Present address: Dean for Research Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32601. Phytopathology 68:441-445. Accepted for publication 6 September 1977. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-441.

Ozone inhibited infection by Pseudomonas glycinea in primary and trifoliolate leaves of soybean inoculated 1 day prior to, or several days after fumigation with 490 μg/m³ (0.25 ppm) O₃ for 4 hr. The protective effect persisted over the period that primary leaves were susceptible to the bacterium. Trifoliolate leaves that were beginning to expand at the time of exposure also were protected when inoculated subsequently. Similar effects were observed when primary and young trifoliolate leaves were exposed to 157 μg/m³ (0.08 ppm) for 4 hr, but not when fully expanded trifoliolate leaves were exposed.