Characterization and Pathogenicity ofRhizoctoniaspp. and Binucleate Rhizoctonia-like Fungi from Turfgrasses in North Carolina

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Abstract
Fungi with Rhizoctonia-like mycelial states were isolated from diseased cool- and warm-season furfgrasses in North Carolina and the species were identified when possible. Fungi were identified as R. solani, R. cerealis, R. zeae, or binucleate Rhizoctonia-like fungi (RLF). Isolates of R. solani were assigned to anastomosis groups (AG) 1, 2, 4, or 5 or could not be assigned to anastomosis groups because of lack of anastomosis with AG tester isolates. Most isolates of R. solani induced foliar blight symptoms on cool-season grasses, but in greenhouse inoculations one isolate from symptomatic bermudagrass (Cynodon dactylon .times. C. transvaalensis ''Tifton 419'') induced a crown rot similar to symptoms observed in the field. Similar inoculations with isolates of R. solani indicated greater virulence on cool-season grasses than warm-season grasses with the exception of the bermudagrass crown-rotting isolate. Isolates of R. cerealis were obtained during periods of cool, damp weather and were associated with a foliar chlorosis of creeping bentgrass (Agrostis palustris). R. zeae was isolated 3 times from diseased tall fescue (Festuca arundinacea) and once from creeping bentgrass during hot weather. Isolates of R. zeae were as virulent on tall fescue and Kentucky bluegrass (Poa pratensis) as the R. solani isolates tested in greenhouse experiments under hot weather conditions.