Characteristics of Hymenial Isolates of Thanatephorus cucumeris on Sugar Beets in Ohio. L. J. Herr, Professor, Department of Plant Pathology, Ohio Agricultural Research and Development Center, Wooster 44691 and Ohio State University, Columbus 43210. Plant Dis. 66:246-249. Accepted for publication 19 May 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-246.

Hymenia of Thanatephorus cucumeris were first found on diseased petioles of crown and root rot diseased sugar beets and 10–14 days later in association with a leaf blade blight during both 1979 and 1980. Hymenial isolates belonged predominately in anastomosis group (AG) 2 (80 of 91 isolates). These isolates were highly virulent on older sugar beets. Isolates other than AG-2 were found only on diseased petioles during 1979 and included nine AG-4 and two binucleate Rhizoctonia-like isolates. The AG-4 isolates were highly virulent on sugar beet seedlings but only moderately to slightly virulent on older plants. The binucleate isolate tested was avirulent on older plants.

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