PROBLEM TO BE SOLVED: To sufficiently control a plant disease without damaging a plant, to accelerate the growth of the plant and to increase nutrients contained in the plant, in a plant growth disease control illuminating device for irradiating the plant with light from an artificial light source. SOLUTION: The illuminating device 1 for plant growth disease control includes a first light source 2 for irradiating far-red light, and a second light source 3 irradiating ultraviolet light, as light sources for irradiating the plant P with light. The irradiating operation of these light sources 2, 3 is controlled by a control part 4. The operation time zone of the control part 4 is set by a time setting part 5. The time setting part 5 sets to put the first light source 2 into irradiating operation for 2-4 hours after sunset and then to put the second light source 3 into irradiating operation for 1-3 hours before sunrise. Since the plant P is sequentially irradiated with the far-red light and ultraviolet light in a time zone from sunset to sunrise, the plant disease can be sufficiently controlled without damaging the plant P. Further, the growth of the plant P can be accelerated, and the nutrients contained in the plant P can be increased. COPYRIGHT: (C)2013,JPO&INPIT
