Occurrence of Beet black scorch virus Infecting Sugar Beet in Europe.

In a survey of soilborne viruses infecting sugar beet in central Spain, Beet black scorch virus (BBSV) was detected in field grown sugar beets with symptoms of rhizomania disease. BBSV was found in all analyzed sugar beet producing regions from central Spain, as well as in bait plants grown in soils with a history of rhizomania from several Western European countries, thereby constituting the first report of BBSV in Europe. BBSV was transferred to Chenopodium quinoa, where it caused chlorotic local lesions from which virus particles were purified. The nucleotide sequence of the 3'-untranslated region of the genomic RNA was determined for 13 European isolates, and sequences were highly similar to those reported for Chinese and U.S. isolates. Sequence comparisons revealed three clusters of sequences, one including most European isolates, one including one European and two Chinese isolates, and the third including the U.S. isolate. BBSV was detected in a number of samples with rhizomania symptoms in which Beet necrotic yellow vein virus went undetected. However, its role in rhizomania disease in Europe, if any, remains to be established.