Inoculation of Jack Pine with a Concentrated Basidiospore Spray of Cronartium quercuum f. sp. banksianae. W. K. Stewart, Research Assistant, Department of Forest Resources, University of Minnesota, St. Paul 55108. R. A. Dietrich, Research Assistant, and R. A. Blanchette, Associate Professor, Department of Plant Pathology, and C. A. Mohn, Professor, Department of Forest Resources, University of Minnesota, St. Paul 55108. Plant Dis. 69:208-211. Accepted for publication 26 August 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-208.

A concentrated basidiospore spray was used to inoculate Pinus banksiana with Cronartium quercuum f. sp. banksianae. Purple stem lesions were observed 2.5 wk after inoculation and galls were observed 14 wk later. Histological examination of symptomatic seedlings 20 and 80 days after inoculation showed intercellular hyphae and abnormal and occluded cortical and xylary cells. This technique appears applicable for large-scale screening of jack pine for resistance to pine-oak rust.