Potato tubers exhibiting necrotic rings/arcs were found in a winter potato crop 'Favorita' in the subtropical area Huidong county, Guangdong province, China, in 2012. When the symptomatic tubers were cut crosswise, light to dark brown necrotic arcs were observed in the tuber flesh. A mini-survey of the crop found 8% symptomatic tubers in an area of 10 meters2. To reveal the causal agent of the disease, reverse transcription-polymerase chain reactions (RT-PCR) targeting 9 common potato viruses including those viruses (e.g, Potato mop-top virus (...
