Disease Note

First Report of Charcoal Rot of Stylosanthes guianensis in Colombia. J. M. Lenné, CIAT, Cali, and ICA, Carimagua, Colombia. L. A. Hernandez R., CIAT, Cali, and ICA, Carimagua, Colombia. Plant Dis. 69:83. Accepted for publication 27 September 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-83E.

Stylosanthes guianensis (Aubl.) Sw. is a promising tropical pasture legume for the acid, infertile soils of the eastern plains of Colombia. During an unusually long dry season from November 1983 to April 1984, severe chlorosis, wilting, and death were observed in 47.4, 52.5, and 24.9%, respectively, of accessions CIAT 1927, 2031, and 10136 of S. guianensis var. pauciflora at the ICA-CIAT Research Station at Carimagua in the eastern plains. Microsclerotia were abundant on roots of dead plants and in associated soil. The causal agent was identified as Macrophomina phaseolina (Tassi) Goid., and J. E. M. Mordue of the Commonwealth Mycological Institute in England confirmed the identity. Charcoal rot has previously been recorded only as an occasional and minor pathogen of S. capitata in Colombia.