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Rhizoctonia solaniand Sclerotium rolfsiiexhibited variable degrees of virulence against the sugarbeet cultivars Raspoly, TOP, and Tribel. In the absence of salinity stress, R. solaniwas more virulent than S. rolfsiiagainst cvs Raspoly and TOP whereas S. rolfsiiwas more virulent against cv Tribel. Virulence of both pathogens against the sugarbeet cultivars was altered under the impact of salinity stress, R. solaniwas more virulent than S. rolfsiiagainst cv Raspoly whereas S. rolfsiiwas more virulent against cvs TOP and Tribel. The pattern of virulence shown by R. solaniand S. rolfsiiagainst the three sugarbeet cultivars in the absence of salt treatment, and against cvs Raspoly and Tribel under salinity stress, was directly correlated with the activities of wall-degrading enzymes produced by these pathogens in vivo, and on cell walls in vitro. Although the extracts of R. solani-infected hypocotyls of cv TOP showed greater wall-degrading activities than S. rolfsii-infected hypocotyls, the latter pathogen was more virulent than the former, suggesting repression of R. solanienzymes in the host tissues.