Bacteria that inhibited growth of the sugarbeet fungal pathogens Phoma betae and Rhizoctonia solani were isolated from sugarbeet (Beta vulgaris) seeds and roots. T hese bacteria include fluorescent pseudo monads, and species of Serratia, Enterobacter, and Bacillus. Inhibition of growth of P. betae and R. solani on solid medium was dependent upon growth medium. inhibition under both low-iron and iron-sufficient conditions suggests that siderophore production by the fluorescent pseudo monads was

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... ot a major factor. Inhibition was not correlated with hydrogen cyanide production by the bacteria. Growth jnhibition was associated with production of phena zine-l-carboxylic acid by certain fluorescent pseudo monads. In greenhouse trials, some of the bacteria that displayed the strongest level of in vitro antagonism sup pressed sugarbeet seedling disease caused by P. betae or R. solani. Certain pseudomonads and strains of Serratia and Enterobacter suppressed both diseases.