First report of Diaporthe passiflorae and Diaporthe nobilis causing a postharvest kiwifruit rot in Sichuan Province, China.
In recent years, postharvest rot diseases of kiwifruit (Actinidia sp.) have caused severe damage in China. Infected fruit were obtained from a commercial farm after 4 months cold storage. Nineteen fruits (21.1%) out of one package showed rot symptoms with dark-brown, sour-smelling lesions. The lesions began as small pale yellow or light brown spots and then enlarged rapidly and formed dark or dark brown lesions. The margins between symptomatic and healthy tissues (4 × 4 mm) were cut from five rotted fruits, surface disinfested in 1% NaClO and 70% ethanol solution, washed, dried, plated on potato dextrose agar (PDA) containing 50 mg/l streptomycin sulfate, and incubated at 25°C for 3 days. Hyphal tips were transferred to PDA to obtain pure cultures. After 7 days, a total of 20 fungal isolates were obtained, including 16 previously reported Botrytis spp., Penicillium spp. and Alternaria spp., and four unknown isolates (DJY16A1-4, DJY16A1-5, DJY16A5-1 and DJY16A5-2). Based on morphological characteristics, molecular data (sequence analysis of the internal transcribed spacer, β-tubulin and translation elongation factor-1 alpha regions) and pathogenicty tests, isolates DJY16A1-4 and DJY16A1-5 were identified as D. passiflorae, while isolates DJY16A5-1 and DJY16A5-2 as D. nobilis. D. lithocarpus was recently reported to cause kiwifruit rot. This is thought to be the first report of D. passiflorae and D. nobilis causing postharvest rot in China.