Pythium ultimum Trow var. ultimum was isolated from soft-rotted fruits of strawberry in a plastic greenhouse of Osaka prefecture. Strawberry fruits infected by Pythium ultimum lost its color and changed like elastic rubber ball. These symptoms were distinguished clearly from the gray mold caused by Botrytis cinerea.
Inhibitory effect of culture filtrate (CCF) of Fusarium oxysporum f. sp. lycopersici on TMV infection was examined by using local lesion test. CCF, which was not dialysable against water, was inhibitive to TMV infection when applied before or after inoculation with TMV. CCF gave a positive reaction with tests for protein and carbohydrate. Both autoclaved and deproteinized CCF effectively inhibited TMV infection. The ethanol-precipitate obtained from deproteinized CCF was shown to be polysaccharides whose molecular weights were between 7×104 and 4×105 by gel permeation column chromatography.