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About Potato Mop Top Virus (PMTV)

PMTV is a virus of the family Virgaviridae, genus Pomovirus. It affects tuber quality by inducing necrotic spots, rings and arches in the flesh of the potato tuber; these necrotic lesions sometimes reach the surface of the tuber, but often can be visible only when the tuber is cut. Tuber necrotic symptoms reduce tuber quality and increase losses for potatoes destined for fresh markets or to be processed into chips and French fries.

Vector — PMTV is transmitted from plant to plant through soil by Spongospora subterranea, a protist which also causes direct damage to potato in the absence of PMTV called powdery scab.

Symptoms — PMTV typically produces no symptoms in potato foliage and the main visible symptoms are expressed in potato tubers as necrotic rings or arches in the tuber flesh.

Management — Currently, the best management option for PMTV is exclusion, making sure the fields are PMTV-free. No management solutions are available yet once a field is contaminated with S. subterranea carrying PMTV. Importantly, PMTV is currently not regulated by certification programs.