IDENTIFICATION OF A 2ND DISTINCT STRAIN OF BEET MILD YELLOWING LUTEOVIRUS USING MONOCLONAL-ANTIBODIES AND TRANSMISSION STUDIES

The variation among isolates of beet mild yellowing luteovirus (BMYV), collected from commercial crops of sugar beet during 1990, 1992 and 1 993, was studied using monoclonal antibodies and transmissions to indi cator species. The common strain of BMYV, which occurs throughout the sugar-beet root growing area, reacts with monoclonal antibodies MAFF 2 4, BWYV-BC-51OH and BYDV-PAV-IL-1, and infects Capsella bursa-pastoris . A second strain, which failed to react with monoclonal antibody BYDV -PAV-IL-1 and which did not infect C. bursa-pastoris, was identified i n 11% of sampled infected plants. The implications of the properties o f this strain for the epidemiology of BMYV are discussed.