Blue LED (light-emitting diodes)-mediated growth promotion and control of Botrytis disease in lettuce

Lettuce plants were grown under red, blue, or white light-emitting diode lights for four weeks after transplantation. Blue-light-treated lettuce exhibited the highest growth in view of root length, leaf area, number of leaves, chlorophyll content, and fresh and dry weight. In addition, the development of gray mold was significantly suppressed in blue-light-treated lettuce where the highest antioxidant activities were observed. The results suggest that the control efficacy of gray mold by Botrytis cinerea in lettuce is closely associated with the increase of antioxidant capacity as well as the development of compact morphology by blue-light treatment.