First Report of Alphapartitiviruses Infecting Alfalfa (Medicago sativa L.) in the United States.

Evidence is presented demonstrating that alfalfa cultivars in the United States could be widely infected with cryptic virus of the genus Alphapartitivirus. The nucleotide sequences of several U.S. isolates were obtained. The biological significance or negative effects of the virus on alfalfa are unknown and require further investigation.