According to data for 2014, China is one of the leading apple producers worldwide, with 2.3 million hectares and 41 million tons of fruit.
During the 2014-2015 season, a survey was conducted in apple orchards in Gansu, Hebei, Henan, Liaoning and Shangdong to assess the incidence of Apple chlorotic leaf spot virus(ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), Apple mosaic virus (ApMV) and Apple scar skin viroid (ASSVd).
Researchers at the Pomology Institute of the Chinese Agricultural Science Academy in Xingcheng took samples of leaves and shoots and extracted their RNA. Molecular analyses showed that protein sequences corresponded to two viruses - ApMV and PNRSV (Prunus necrotic ringspot virus).
The leaves of seven PNRSV-positive apple trees also showed symptoms of the Apple mosaic virus, so researchers hypothesised that the PNRSV could be associated with it. The PNRSV virus belongs to the Ilarvirus genus and typically causes fruit yield loss as well as affecting fruit maturity and tree growth in Prunus species such as almond, apricot, peach, plum and cherry.
Despite PNRSV having worldwide distribution in stone fruits, this virus has only been reported once (India - 2008) on apple trees. Researchers reported that "to our knowledge, this is the first report of PNRSV in domestic apples in China. Further research is needed to assess the effect of PNRSV on the performance and quality of the fruit."
Source: G. J. Hu, Y. F. Dong, Z. P. Zhang, X. D. Fan, F. Ren, Z. N. Li, and J. Zhou, 'First Report of Prunus necrotic ringspot virus Infection of Apple in China', September 2016, Plant Disease, Volume 100, Number 9, page 1955. apsjournals.apsnet.org/doi/full/10.1094/PDIS-01-16-0079-PDN