Effects of ozone treatment on postharvest decay of peach fruits in cold storage

The maintenance of high-quality standards for prolonging the shelf life of fruit is a priority for horticultural products, and fungal infection is one of the main problems of peach fruit in pre- and postharvest. This study investigated the effects of preharvest treatment using two types of sprayers (standard and innovative with flow control), and postharvest treatment using ozone in storage temperature on the quality of peach fruit. The experiments were carried out in Marche Region, Central-Eastern Italy, on peach cultivars Summer Royal and Extreme 486, sprayed with fungicides (tebuconazole in 2019 and 2020 and boscalid + pyraclostrobin in 2021) in the field and after 7 days harvested separately for each type of sprayer. Immediately after harvest, peach fruits were stored at 4°C with or without ozone treatment (45 ppb continuously in 2019 and 2020, and in alternating between 50 and 200 ppb during the day and night in 2021) for 10, 20 and 25 days. Fruits were removed from cold storage, transferred at 23-25°C and then the decay was measured daily for 6/10 days shelf life. Concentration of 200 ppb used during the night on ‘Extreme 486’ induced phytotoxic effects on peach fruits. The main agent of rot identified on peach fruit during shelf life was Monilinia spp. Treatment with ozone during cold storage reduced decay incidence in a range among 10 to 70%. In all trials, standard sprayer protected the fruits better than innovative one. The application of ozone can contribute to the management of postharvest diseases of peaches, and concentrations to be applied need to be tested on specific cultivars to monitor eventual phytotoxic effects.