The present invention provides: a composition for controlling plant diseases comprising, as active ingredients, 4-oxo-4-[(2-phenylethyl)amino]-butyric acid and tolclofos-methyl; a method for controlling plant diseases which comprises applying effective amounts of 4-oxo-4-[(2-phenylethyl) amino]-butyric acid and tolclofos-methyl to a plant or soil for growing plant; and so on.