VIEW ARTICLE

Influence of Soil Water and Temperature on Root Necrosis of Peach Caused by Pythium spp.. J. A. Biesbrock, Former Graduate Student, Department of Plant Pathology and Plant Genetics, University of Georgia, Athens 30601, Present address of senior author: Department of Soil Science, University of Minnesota, St. Paul 55101; Floyd F. Hendrix, Jr., Associate Professor, Department of Plant Pathology and Plant Genetics, University of Georgia, Athens 30601. Phytopathology 60:880-882. Accepted for publication 23 December 1969. DOI: 10.1094/Phyto-60-880.

Conditions of soil water and temp had a marked and differential influence on disease severity in peach induced by Pythium vexans and P. irregulare. Growth comparisons showed that stunting induced by P. vexans was most severe at periodically-saturated soil water regimes, but was unaffected by temp of 13, 21, and 29 C. By contrast, stunting induced by P. irregulare was most severe at 13 C, but was unaffected by either periodically-saturated or nonsaturated soil water regimes. Our evidence suggests that disease severity induced by P. vexans was correlated with the favorable influence of periodic excesses of water on zoospore productions. By contrast, disease severity induced by P. irregulare was correlated with temp and was unaffected by conditions of soil water because sporangia formed germ tubes.