Powdery Scab of Potatoes

Spongospora subterranea


A fungal disease that causes brown, round to oval blister like scabs or swellings on Potato tubers. Initially they are about 2 mm diameter and may grow to 10 mm diameter. Brown powdery spores are released when the skin breaks and curls back. Infected roots look normal.

Species Affected:

Tomato, Potato and some Solanaceous weeds.


Lasts in the soil for many years.

Infection occurs when soil moisture is high and soil temperatures are below 180C.

Life Cycle:

Origin and History:



Management and Control:

Use healthy seed or sets.

Rotate areas where potatoes are planted.

Avoid planting Potatoes on infected soil.

Avoid planting Potatoes into poorly drained areas or improve drainage.

Avoid watering around the time of tuber initiation if possible.

Related and Similar Species:




Collated by HerbiGuide. Phone 08 98444064 for more information.