Potato tuber test - potato mop top virus and tobacco rattle virus (PMTV & TRV)

Spraing is the term given to a range of internal and external symptoms in potato tuber flesh consisting of brown, necrotic rings, arcs and flecks.

Symptoms can be confused with physiological problems, such as internal rust spot. Symptoms may not be seen at harvest but can develop in store. Chemical control is of limited use – ensuring disease free seed and knowledge of presence of vector and inoculum presence in field is essential to disease management. Planting diseased tubers in clean land could be a source of further spread of virus inoculum

Visual examinations can be highly subjective and inaccurate due to the similarities with a range of other potato viruses, laboratory testing is advised.