"Oat is among the most versatile grain in the family , though it is used primarily for livestock feed and human consumption. Several oat species, such as ' (common oats), ' (Algerian or red oat), ' (naked oats), and ' (sterile or animated oat), are produced commercially and together account for oats being the seventh most grown cereal globally. Viral genera across the families , , , and often cause diseases in oat species, thus causing moderate to severe yield losses annually. In this chapter, we explore the transmission mechanisms of the most important viruses that pose threats to production of oats. Current methods for identifying viruses include purification by nucleic acid assays, symptomatology, and electron microscopy–based, physical examination and serology. Early diagnosis of viral agents causing diseases plays an important role in the management of plant diseases."