VIEW ARTICLE

Etiology

Interactive Effects of Freezing and Common Root Rot Fungi on Winter Wheat. J. A. Fernandez, Associate professor of Plant Pathology, University of Wyoming, Laramie 82071; D. S. Wofford(2), and J. L. Horton(3). (2)(3)Assistant professor of Crop Science, and research technician, respectively, University of Wyoming, Laramie 82071. Phytopathology 75:845-847. Accepted for publication 4 March 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/Phyto-75-845.

Wheat plants inoculated with Bipolaris sorokiniana and Fusarium acuminatum were subjected to freezing (- 12 C) under controlled conditions. Plant tops were clipped and the effects of fungi, freezing, and the interactions of these factors on plant regrowth (top dry weight and percent reattainment of top dry weight measured prior to temperature treatments) and plant health (number of healthy adventitious coronal roots) were studied. If plants were not frozen, neither fungus significantly affected reattainment of top weight and only B. sorokiniana reduced top dry weights and the number of healthy coronal roots compared to those of uninoculated plants. After the plants were subjected to freezing, however, both fungi significantly reduced top dry weight, percent reattainment of top weight and the number of healthy coronal roots. These results and field observations suggest that freezing may predispose wheat to damage by fungi normally considered to be weak pathogens and exacerbate the damaging effects of fungi known to be vigorous pathogens.