REA O DE CULTIVARES DO FEIJOEIRO COMUM àS PODRID ES RADICULARES CAUSADAS POR Rhizoctonia solani E Fusarium solani f. sp. phaseoli

REACTION OF COMMON BEAN CULTIVARS TOROOT ROT CAUSED BY Rhizoctonia solaniAND Fusarium solani f. sp. phaseoliRhizoctonia solani Kuhn is a necrotrophic fungus andsoil inhabitant that attacks great number of vegetable species. Inbean plants, R. solani can induce different symptoms includingtoppling, root and colon plant rottenness. Fusarium solani (Mart)Sacc. f. sp. phaseoli (Burcholder) occurs in practically all beanproducing areas in Brazil and can cause root rots and death tobean plants. This study evaluated the reaction of commercialcommon bean cultivars growing in R. solani or F. solani f. sp.phaseoli infested soil, under green house conditions. Theexperimental design was entirely randomized, with 24 treatmentsand four replications. A Oxisol was infested with trituratedsorghum grains that were previously colonized by R. solani (1.0g/1.4 L of soil) or F. solani f. sp phaseoli (8.0 g/1.4 L of soil). Thedisease evaluations were accomplished 21 days after planting.All plants were carefully removed, their root systems werewashed in running water and the disease severity was evaluatedaccording to Abawi & Pastor-Corrales (1990) scale for diseaseseverity. The cultivar behavior ranged according to the inoculatedpathogen, all cultivars were susceptible with different degrees ofsusceptibility. Among evaluated common bean cultivars Pérolawas less susceptible to R. solani, and Radiante was lesssusceptible to F. solani f. sp. phaseoli.