VIEW ARTICLE

Ecology and Epidemiology

Survival of Teliospores of Sphacelotheca reiliana in Soil. C. A. Matyac, Department of Plant Pathology, University of Minnesota, St. Paul 55108, Present address: Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616; T. Kommedahl, Department of Plant Pathology, University of Minnesota, St. Paul 55108. Phytopathology 76:487-490. Accepted for publication 18 November 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-487.

Teliospores of Sphacelotheca reiliana in soil of field microplots decreased to 42% of the original population in 6 mo and to 4% after 3 yr. In controlled environments, the greatest reduction in spore populations at all temperatures (0, 15, and 25 C) occurred at matric potentials of -0.5 bar, at which an average of 29% of the spores were recovered after 30 wk. At -11.1 and -44.0 bars, 52 and 89%, respectively, of the spores remained. Temperature and interactions of temperature x matric potential also significantly affected decreases in spore number, with the greatest decreases occurring at high temperatures and high matric potentials. Application of organic amendments with low C:N ratios significantly reduced inoculum density in microplots after 0.5, 1.0, 1.5, and 2.0 yr, but did not significantly affect the survival of teliospores either in microplots after 3.0 yr or in the controlled environments. In bioassays of incubated teliospores, incidence of infection also decreased with time, but soil type or organic amendments had no effect. Germination of spores on agar was reduced by 90% after 6 mo in microplots and by 63% in soils incubated at high moisture contents at 25 C.