Host Range and Cultural Characteristics of Cercospora zebrina from White Clover in North Carolina. Scot C. Nelson, Graduate Research Assistant and Associate Professor, Department of Plant Pathology, North Carolina State University, Raleigh, 27695-7616. C. Lee Campbell, Graduate Research Assistant and Associate Professor, Department of Plant Pathology, North Carolina State University, Raleigh, 27695-7616. Plant Dis. 74:874-878. Accepted for publication 16 May 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0874.

An isolate of Cercospora zebrina from white clover (Trifolium repens) was pathogenic to 24 species in 12 genera of legumes in greenhouse tests. This report is apparently the first evidence of pathogenicity of a white clover isolate of Cercospora to species of Apios, Arachis, Glycine, Lespedeza, Lotus, Phaseolus, and Vigna. The isolate was not always more virulent on white clover; pea cultivars (Pisum sativum) were more severely diseased. Five isolates of C. zebrina from white clover in four counties in North Carolina manifested significant (P < 0.05) isolate × host interactions on six leguminous hosts. The Vance Co. isolate was the only one that was more virulent on white clover than on other hosts and caused more disease on white clover, subclover (T. subterraneum), and alfalfa (Medicago sativa) than the other isolates. The Franklin Co. isolate was more virulent on arrowleaf clover (T. vesiculosum) than on other hosts. Optimum radial growth on V-8 juice agar occurred at 24 C for all five isolates. Growth differed (P = 0.05) among isolates at 16, 20, 24, and 28 C, which indicated that some isolates were more tolerant of extremes in temperature in vitro. One isolate produced significantly more conidia in vitro than the other four. Mean length of conidia produced in vitro did not differ among isolates.