ABSTRACT
Plant viruses are viruses that affect plants. Like all other viruses, plant viruses are obligate intracellular parasites that do not have the molecular machinery to replicate without a host. Plant viruses can cause damage to stems, leaves and fruits and can have a major impact on the economy because of food supply disruptions. Viruses also cause many important plant diseases and are responsible for huge losses in crop production and quality in all parts of the world. Strategies for the management of viral diseases normally include control of vector population using insecticides, use of virus-free propagating material, appropriate cultural practices and use of resistant cultivars. Rapid advances in the techniques of molecular biology have resulted in the cloning and sequence analysis of the genomic components of a number of plant viruses. In several viruses, truncated genomic components are often detectable in infected tissues, which interfere with the replication of the genomic components.
