Disclosed is a lighting device for use in the control of a plant disease, which has a light source capable of emitting light containing ultraviolet ray. The light source can emit both of UV-B having a wavelength component with a wavelength of about 280 to 340 um and UV-C in which a wavelength component with a wavelength of about 255 nm or less is cut off from wavelength components with wavelengths of about 100 to 280 nm to plant in a superimposed manner. The irradiation of a pant with the UV-C and the UV-B ensures to further inhibit the spore formation or the hypha growth of a filamentous fungus that causes a disease or the like, and to induce a resistance against a disease in the plant.
