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