Panicum mosaic virus (PMV) is a positive-sense single-stranded RNA viral pathogen that infects plant species in the panicoid tribe of the grass family, Poaceae. The pathogen was first identified in Kansas in 1953 and most commonly causes disease on select cultivars of turf grass, switchgrass, and millet. The disease most commonly associated with the panicum mosaic virus pathogen is St. Augustine Decline Syndrome, which infects species of turf grass and causes chlorotic mottling. In addition to St. Augustine Decline, panicum mosaic virus is responsible for chlorotic streaking and mild green mosaicking in select cultivars of switchgrass and millet. History PMV was first observed in Kansas in 1953. It was originally noted to infect switchgrass (Panicum virgatum), and was observed infecting St. Augustine grass (Stenotaphrum secundatum) in Texas in 1966. The strain specific to St. Augustine grass has since been observed in Arkansas, Louisiana, Mississippi and South Carolina in the United States, as well as in Mexico. Other strains have been identified infecting centipedegrass (Eremochloa ophiuroides). Foxtail millet (Setaria italica), white proso millet (Panicum miliaceum) and pearl millet (Pennisetum glaucum) have also been used to propagate PMV and panicum mosaic satellite virus (SPMV), and mechanical transmission can occur to maize and some cultivars of common wheat (Triticum aestivum). Classification Panicum mosaic virus is assigned to the genus Panicovirus, a member of the plant virus family Tombusviridae. Members of Tombusviridae are transmitted as positive sense single-stranded non-enveloped RNA viruses, with an icosahedral capsid. PMV itself has a genome of 4,326 nucleotides, encapsulated into 30-nm particles by a capsid protein of 26 kDa. PMV was placed in the genus Panicovirus because of its limited monocot host range and lack of an additional 5'-ORF. PMV is serologically related to Molina streak virus and Maize mild mottle virus. Satellite panicum mosaic virus There exists a satellite virus to panicum mosaic virus. Although little is known about the satellite panicum mosaic virus, the pathogen is believed to play a role in the infection process because when combined with panicum mosaic virus, the satellite virus causes symptoms to appear earlier in the growing season and results in a more severe infection. Because of the change in disease virulence to the main viral pathogen, panicum mosaic virus and satellite panicum mosaic virus are believed to cause synergistic effects to their hosts. Satellite panicum mosaic virus cannot produce its own replication nor movement proteins, thus it depends entirely on