Improvement of grapevine virus A (GVA) diagnosis by ELISA testing.
In order to establish the distribution of grapevine virus A (GVA) in plant, different organs and tissues (leaf blade, petiole, tendril, root, dormant cutting, green shoot, shoot tip, inflorescence, bunch) collected from infected grapevines belonging to Servant variety were used as source of antigen. The samples were tested by DAS-ELISA-biotin method with commercial antiserum to detect the virus and also to estimate the level of infection. The virus was detected over the course of the entire year, both in the vegetation and dormancy; the best sources of virus were basal mature leaf and phloem tissue from mature cane, respectively, GVA was not reliable detected in young material and bunch. The efficiency of detection of grapevine viruses based on ELISA tests depends on the source of the virus and the time of the year in which the sampling is performed.