Apple viruses and viroids

Apples are the third most produced fruit in world, behind bananas and oranges, terms of volume. Over past ten years, Serbia's apple production has nearly doubled. less subjected to viral viroid attacks than other species. Most viruses cause no visible symptoms on plant's organs, trees either seem be good condition or, case sensitive cultivars, their yield is reduced. Apple stem pitting virus (ASPV), grooving (ASGV), chlorotic leaf spot (ACLSV), mosaic (ApMV) four economically important widely distributed viruses. Among viroids, scar skin (ASSVd) particularly destructive for production.