Inhibition of biofilm formation by Streptomyces cultures against Ralstonia solanacearum (a). Percentage inhibition by spectrophotometer analysis (b). Microscopic visualization a UP1A-1, b UP1A-4, c UP2A-9, d UT2A-30, e UT3A-39, f UT4A-49, g UT6A-57 and h control