Considerable variation was found in the growth, color, zonation, sclerotia, mycelial texture and virulence of seven isolates of R. solani. Six multinuclease and one binuclease isolates were determined, demonstrating that it is indispensable to determine this characteristic in trials with this pathogen. The isolates were placed in three anastomosis group AG -1, AG -2 and AG -4; but with electrophoresis of isoenzymes it was found that the band models were different for the known rest AG iso lates and those isolates proven in this study which questions the importance of anastomosis qroups. Ecotypes of Centrosema spp. and P. phaseoloides were more affected than those of S. guianensis, D. ovalifolium and S. capitata. The reaction on damage by R. solani was differencial for ecotypes C IAT 1283 (tardio) and 184 (comrno n) and was related to age. In general, the disease increased with age in the tardio and decreased or was independent of age in the cornrnon: the tardio was more affected; forage losses were not cosiderable but the effect on the digestibility was noted; the regrowth capacity was good in the cornrnon. A stimulus in the growth of plants of S. guianensis and D. ovalifolium was observed.