Plant diseases caused by pathogens mainly viruses are of great economic importance. Virus’s infections are responsible for losses in crop yield and quality in all parts of the world. Plant viruses cannot be directly controlled by chemical application. Consequently, prevention based on early detection and identi?cation is the only effective measure to manage the plant virus disease. Many viruses are good antigens and this property has been widely exploited to produce specific antibodies that can be used for virus detection and for examining relationships between viruses. Hybridoma technology revolutionized antibody production and eliminated many problems associated with polyclonal antiserum. Therefore, monoclonal antibodies promise considerable improvement of virus diagnosis with regard to specificity, sensitivity and reproducibility, by integrating several serological tests.