Antifungal Effect of Blue LED Irradiation on the Blue Mold, <i>Penicillium italicum</i>, in Satsuma Mandarin Fruits

摘要： The antifungal effect of blue LED (light emitting diode: maximum emission wavelength 465 nm, 80 μmol?m-2?s-1) irradiation on the blue mold, Penicillium italicum, in satsuma mandarin (Citrus unshiu Marc.) fruits after harvesting was investigated. Blue LED irradiation for 6 days after inoculation with Penicillium italicum significantly reduced symptom development in the fruits compared to that observed with dark treatment. The sporulation and mycelium area were markedly reduced by blue LED irradiation. On the other hand, blue LED irradiation for 6 days before inoculation reduced symptom development when the inoculum dose was low. Blue LED irradiation did not affect the fruit quality, except for the citric acid concentration and moisture loss. These results indicate that blue light irradiation could directly inhibit fungal growth in satsuma mandarin fruits and induce an antifungal response against the blue mold.