Plant viruses are submicroscopic particles that are often transmitted from plant to plant by a vector such as an insect. Once in the plant, more virus is produced, and it spreads systemically throughout the plant.
Plants infected with a virus usually remain infected for their entire life.
Viral infection often results in reduced or abnormal plant growth and lower yield. However, some viruses cause mild infections which produce no apparent symptoms and do not greatly reduce growth or yield. Viral symptoms and physiological disorders, such as herbicide damage, are often confused because both may affect normal plant growth and development. Management of viruses depends upon preventive control measures, because there are no chemicals available to cure or prevent virus infections. Several strategies are used for controlling viruses.