Resumo

ORTEGA-ACOSTA, Santo Ángel et al. Distribution and Frequency of Organisms Associated to Disease "Black Leg" of Roselle (Hibiscus sabdariffa L.) in Guerrero, México. Rev. mex. fitopatol [online]. 2015, vol.33, n.2, pp.173-194. ISSN 2007-8080.

The distribution and frequency of organisms associated with the "black leg" of roselle was studied in 2011 in Guerrero, where 12 commercial plots were evaluated. The identification was based on cultural characteristics and taxonomic keys. Molecular characterization was performed by amplifying the internal transcribed spacer region (ITS) of the rDNA. The isolated organisms were Phytophthora parasitica, Macrophomina phaseolina, Fusarium oxysporum, Fusarium incarnatum, Fusarium solani, Phomopsis longicolla, Glomerella cingulata and Colletotrichum truncatum. P. parasitica was the most frequent specie (72.4 %), distributed in 10 of the 12 sites, followed by F. oxysporum widely distributed but with low frequency (10.6 %), M. phaseolina was isolated from four sites with frequency 10.9 %. F. incarnatum, F. solani, P. longicolla, G. cingulata and C. truncatum showed low frequency (0.4 to 2.4 %) and distribution. Molecular analysis corroborated the identification of organisms. In pathogenicity tests, P. parasitica, M. phaseolina and F. incarnatum were pathogenic. This is the first report in Mexico for M. phaseolina and F. incarnatum as pathogen of roselle.

Palavras-chave : root and stem rot; oomycete; fungus complex; Phytophthora parasitica; Macrophomina phaseolina.

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