Root Rot of Soybean Caused by Cylindrocladium clavatum in Central Brazil. J. C. Dianese, Associate Professor, Departamento de Biologia Vegetal, Universidade de Brasília, 70910, Brasília, DF, Brazil. W. R. C. Ribeiro, Graduate Research Associate, Departamento de Biologia Vegetal, Universidade de Brasília, 70910, Brasília, DF, Brazil, and A. F. Urben, Researcher, CENARGEN/EMBRAPA, SAIN, Parque Rural, C.P. 10.2372, 70000 Brasília, DF, Brazil. Plant Dis. 70:977-980. Accepted for publication 30 January 1986. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-977.

A new root disease of soybeans caused by Cylindrocladium clavatum in central Brazil is reported. The fungus causes black rot of the taproot and base of the hypocotyl. Under field conditions, patches of stunted plants are found that may wilt and die. Isolates of the fungus from soybeans also infected pea (Pisum sativum). Rhizoctonia solani, Neocosmospora spp., Fusarium oxysporum, F. solani, F. roseum, Macrophomina sp., Meloidogyne incognita, and M. javanica were also isolated from diseased soybean roots. Pathogenicity of R. solani and Neocosmospora sp. was established in single inoculations and in combinations with C. clavatum. The role of other fungi and nematodes is being investigated.

Keyword(s): Glycine max, soybean root rot.