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Cytology and Histology

Mode of Infection and Early Colonization of Slash Pine Seedlings by Cronartium quercuum f. sp. fusiforme. Thomas Miller, Plant pathologist, USDA-Forest Service, School of Forest Resources and Conservation, University of Florida, Gainesville 32611; Robert F. Patton(2), and Harry R. Powers, Jr.,(3). (2)Professor of Plant Pathology and Forestry, Department of Plant Pathology, University of Wisconsin, Madison 53706; (3)Plant pathologist, Forestry Sciences Laboratory, Athens, GA 30602. Phytopathology 70:1206-1208. Accepted for publication 9 June 1980. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1980. DOI: 10.1094/Phyto-70-1206.

After artificial inoculation of slash pine seedlings with basidiospores of Cronartium quercuum f. sp. fusiforme, the fungus produced an infection peg which penetrated through the cuticle and cell walls of the epidermal cells of hypocotyls, cotyledons, stems, and primary and secondary needles. In some instances an appressorium was formed. Within infected cells, the fungus developed a vesiclelike structure, or an irregularly oblong primary hypha usually single-celled, but occasionally several-septate. From these structures, a hypha penetrated the cell wall and developed a largely intercellular mycelium, from which typical haustoria were produced in some cells.