Silver Scurf Potato Disease
Silver scurf (Helminthosporium solani) is a fungal potato disease which causes blemishes on the tuber’s surface.
Common Signs and Symptoms of Silver Scurf
The main symptom of silver scurf is, as the name suggests a silvery appearance of dead skin on the surface of infected tubers. The tuber’s skin often eventually flakes off, leaving them dehydrated and shrivelled looking.
Because tubers infected with silver scurf often have a sooty appearance, it is very often confused with black dot, however they are easily distinguished by the silvery sheen when compared side-by-side.
Common Causes and Conditions of Silver Scurf
Silver scurf is almost always derived from infected seed (it is very difficult to spot signs of the disease in seed) and once planted, is encouraged by warm and humid conditions.
The longer that tubers are left in the soil, the more severe the problem can become.
The disease is often further spread during storage if kept in warm, damp conditions.
Immune / Vulnerable Varieties
There are no potato varieties that show particularly good resistance or vulnerability to silver scurf.
Controlling Silver Scurf
Cultural and Methods:
Wash and carefully check samples of your seed for signs of the disease as soon as they arrive with you.
Silver Scurf can be controlled by harvesting early and ensuring that stored potatoes are kept in dry, cool conditions.
If applied within a fortnight of lifting, Thiabendazole may reduce the incidence of silver scurf, providing that it has not already been applied to the seed.