First Report of Brown Spot on Stored Apple Fruits Caused by Stemphylium vesicarium in Serbia

Abstract

Apple is one of the most economically important fruit crops worldwide, and postharvest fungal diseases can cause significant losses during storage (Petreˇs et al. 2020). Apple fruits (cv. Fuji) with necrosis symptoms were collected during the fall of 2022 from an ultra-low-oxygen cold storage facility in Titel, Serbia. The fruits originated from the apple orchards in Titel (45°12947.10N, 20°15923.60E). The pathogens were isolated from collected fruit samples using standard phytopathological techniques. Fruits were surface-sterilized, rinsed with sterile water, and aseptically cut in half, and small fragments collected from the border of healthy and diseased tissue were placed on potato dextrose agar (PDA) medium in Petri dishes and incubated at 25 ± 1°C in the dark for 7 days. The obtained 11 isolates were identified to the genus level as Alternaria (incidence, 46%), Penicillium (36%), Fusarium (9%), and Stemphylium (9%) based on their morphological characteristics. Pathogenicity of all the isolates was confirmed on apple fruits of cultivars Fuji and Golden Delicious. The fruits were surface-sterilized, sprayed with 5 ml of conidial suspension (1 × 105 conidia/ml), and incubated at room temperature for 21 days. Symptoms developed on inoculated fruits were the same as symptoms observed on apple fruit samples collected from cold storage.