Factors Affecting Germination of Teliospores of Puccinia obtegens. S. K. Turner, Former Research Assistant, Department of Plant and Soil Science, Montana State University, Bozeman 59717 . A. Kwiatkowski, Exchange Scientist from Poland, P. K. Fay, Associate Professor of Agronomy, Department of Plant and Soil Science, and D. C. Sands, Associate Professor, Department of Plant Pathology, Montana State University, Bozeman 59717. Plant Dis. 70:390-391. Accepted for publication 4 November 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-390.

Extracts of Canada thistle (Cirsium arvense) roots stimulated germination when flooded over teliospores on water agar. Maximum percent germination was obtained in darkness at 21 C. Percent germination was greater after 6 than after 3 mo of storage at 4 C and varied with collection dates (no germination before 15 August) and locations.

Keyword(s): biological weed control, Puccinia punctiformis.