Distinguishing Teliospores of Tilletia controversa from Those of T. caries by Fluorescence Microscopy. V. O. Stockwell, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. E. J. Trione, Research Biochemist, Agricultural Research Service, U.S. Department of Agriculture, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. Plant Dis. 70:924-926. Accepted for publication 11 April 1986. 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, 1986. DOI: 10.1094/PD-70-924.

Teliospores of the common bunt pathogen of wheat (Tilletia caries) and the dwarf bunt fungus (T. controversa) are difficult to distinguish by light and electron microscopy. An epifluorescence microscopy method was developed to identify teliospores of these fungal species. Teliospore samples were mounted in immersion oil and viewed with blue light. The reticulated wall layer of T. controversa teliospores fluoresced yellow-orange and the spores appeared spherical. Teliospores of T. caries had a nonfluorescing reticulated wall layer, yellow-fluorescing globules were present in the cytoplasm, and the teliospores were deformed. This rapid, sensitive method for teliospore identification should be useful to monitor international wheat shipments for teliospores of T. controversa.