PMTV is one of two viruses causing spraing in potato. Infections are commonly associated with tuber internal blemishing (see also TRV). This is a significant cause of rejections of both ware and processing crops. Symptoms do not increase during storage.
Skin spot (Polyscytalum pustulans) is a fungal disease of potato tubers which is generally symptomless until after approximately 2 months of storage, when the infected tissue begins to show spots on some varieties.
Ring rot is caused by the bacterium Clavibacter michiganensis subsp. sepedonicus. The disease is favoured by cooler climates and, already established in northern and Eastern Europe, could readily establish under UK conditions.