See:
Cherry (Prunus spp.) - Prunus Necrotic Ringspot
Notes The cherry rugose mosaic strain of Prunus necrotic ringspot virus produces "boating" and turned-up leaf tips, delayed fruit maturity (up to 3 weeks), and enations (ridges of rasp-like growth) on undersides of leaves. Leaves with enations are often thicker and stiffer than normal leaves. Severe monetary loss occurs from delayed maturity of the fresh market cultivars such as Bing and Lambert. Smaller losses occur from the delayed maturity of fruits for the brine trade. Trees infected with the rugose mosaic strain set a very light crop that matures late.