Potato mop-top virus

Potato mop-top virus (PMTV) is a plant pathogenic virus transmitted through the vector Spongospora subterranea that affects potatoes. PMTV belongs to family of Virgaviridae, and the genus Pomovirus (Potato mop-top virus). The virus was first identified in 1966 by Calvert and Harrison in Britain, and is now reported in many other potato cultivating regions of the world including Canada, China, Pakistan, Japan, Tasmania, the United States, some South American countries and many parts of Europe. Many disease management systems have been found to be ineffective against the virus, although a combination of sanitation and vector controls seems to work well.

from Wikipedia