 The virus itself is referred to as Watermelon Mosaic Virus II or WMV-2 and is an isolate of the U.S. WMV-2 is a ssRNA positive strand virus that is part of the Potyviridae or Potyvirus clade.Like all RNA viruses, it contains a protein capsid which protects the inner viral RNA.Watermelon mosaic virus is best known for causing disease in most cucurbits and some legumes, though experimentally it has been shown to have a broader host range than almost all other potyviruses.