Suppression of blue mold symptom development in satsuma mandarin fruits treated by low-intensity blue led irradiation

Abstract

Blue mold (Penicillium italicum) is a major postharvest pathogen of citrus. Here, we investigated the mitigating effect of blue light-emitting diode (LED) irradiation on blue mold in satsuma mandarin (Citrus unshiu Marc.) fruit after harvesting. We examined the growth and development of blue mold subjected to blue LED irradiation of two different intensities in vitro. High-intensity blue LED with an emission peak of 465 nm and fluency of 80 molm-2s-1, and low-intensity blue LED with an emission peak of 465 nm and fluency of 8 molm-2s-1 significantly reduced the growth of P. italicum. In addition, wounded fruits inoculated with P. italicum were irradiated with high-and lowintensity blue LED for 6 days and changes in blue mold symptoms were monitored. The results indicate that not only high-intensity, but also low-intensity blue LED treatment significantly reduced blue mold symptoms in fruit; the most pronounced inhibitory effect was exerted on P. italicum sporulation. These results show that treatment with low-intensity blue LED irradiation is sufficient to reduce blue mold symptom development and is a promising safe approach to control postharvest spoilage in mandarin fruit.