Application of combined treatment for control of Botrytis cinerea in phytosanitary irradiation processing

Phytosanitary treatments are required to disinfest quarantine pests and pathogens in agricultural commodities. Gray mold in fruit is caused by Botrytis cinerea, which is one of the major postharvest pathogen of apple and pear. Irradiation treatment is a viable alternative for phytosanitary purposes and a useful nonchemical method for controlling pests and postharvest pathogens. An irradiation dose of over 0.4 kGy is used for the control of insects and fungal disease in fresh fruit, but a loss of firmness occurs. Combined treatments are needed to reduce the irradiation dose in phytosanitary irradiation processing. This study focuses on the application of combined treatments to reduce the loss of fruit quality when fresh fruit is irradiated for phytosanitary purposes. Comparing the antifungal activity against B. cinerea, while gamma irradiation showed no antifungal activity at a dose of 1.0 kGy, combined treatments (nano Ag particle, nano-sized silica silver) at a dose of 1.0 kGy showed the strongest antifungal activity. This study demonstrates the synergistic impacts of combined treatments in phytosanitary irradiation processing. Taken together, the combined treatments may affect reduction of fruit injury that occurred with irradiation only, meaning that the use of combined treatments with gamma irradiation is significantly effective for the preservation of fruit quality.