Characterization and microbiological evaluation of the red compounds, associated with red rot idsease of sugar cane.

The red coloured compounds, isolated from sugar cane tissues infected with red rot, were phenolic and included a mixture of flavonoid compounds. Two of these compounds were purified and partially characterized. Neither the mixture of the coloured compounds nor any of its individual compounds exhibited in vitro activity against the causal organism Physalospora tucumanensis. One of the purified compounds showed in vitro activity against Bacillus subtilis. The role of the red coloured compounds in the mechanism of disease resistance is discussed.