Floral Smut of Viola bicolor in Georgia. K. M. T. Cason, Department of Plant Pathology, University of Georgia, Athens 30602. E. S. Luttrell, Department of Plant Pathology, University of Georgia, Athens 30602. Plant Dis. 72:1077. Accepted for publication 7 September 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-1077A.
Urocystis kmetiana Magn. was found in late April at two locations in Athens, Georgia, on the field pansy, Viola bicolor Pursh (=V. rafinesquii Greene), a common element of the spring flora in lawns. This is an extension of the range for this fungus in North America and the first report of a smut on a dicot in Georgia. Intermingled plants of European field violet, V. arvensis Murray, a similar introduced species, were water resistant. This disease has incorrectly been called a seed smut; it is a floral smut. Systemic infection was infered from the progressive smutting of all flowers on infected plants. Hypertrophy of the receptacle and ovary produced flattened hemispherical green galls distinguishable from the ellipsoidal developing ovaries. A few aborted seeds were often present ncar the apex of the ovarian cavity. Since teliospores began to develop at an early stage. the diagnosis could be confirmed by splitting the gall. In infected plants, Ihe first flower, including the corolla, seemed normal: only a tiny pocket of teliospores was visible in the aborted ova ry. The second and third flowers had progressively lesser development of the corolla, and in succeeding flowers the corolla never appeared.