VIEW ARTICLE

Ecology and Epidemiology

Temperature Effects on Take-all of Cereals Caused by Phialophora graminicola and Gaeumannomyces graminis . R. W. Smiley, Associate professor, Department of Plant Pathology, Cornell University, Ithaca, NY 14853, First author is currently superintendent and professor of plant pathology, Columbia Basin Agricultural Research Center, Oregon State University, Pendleton 97801; M. C. Fowler(2), and K. L. Reynolds(3). (2)(3)Research support specialist, and graduate research assistant, respectively, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Phytopathology 76:923-931. Accepted for publication 9 April 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-923.

Gaeumannomyces graminis var. tritici causes take-all of cereals at low to moderate temperatures. Phialophora graminicola is often also present in roots of cereals and was recently found to cause disease at high temperatures (above 24 C) in turfgrasses. Previous studies with P. graminicola on cereals, all conducted at 22 C or less, have shown this fungus to be avirulent. The relative virulence of P. graminicola and G. g. var. tritici was, therefore, assessed on wheat, oats, and barley grown at constant 14, 24, or 29 C. Severe take-all resulted from G. graminis at 14 and 24 C, and from P. graminicola at 29 C. A second study, in which wheat was grown initially at 14, 24, or 29 C, and then some plants transferred to 29 C, indicated that wheat was only susceptible to damage from P. graminicola when the plants were at high temperature during the seedling stage. A third study indicated that winter wheat, spring wheat, barley, and triticale were most susceptible to root rots by both pathogens, rye was intermediate, and oats and corn were least susceptible. Further evaluation of the potential for P. graminicola to complicate the etiology of take-all is needed where winter cereals are sown early into warm soils or where spring wheat or barley is sown later than normal.