Pitted or raised symptoms on tubers can be:
- Shallow, raised or deep lesions surrounded by corky tissue, they may be circular or sometimes star shaped > Common scab,
- Purplish Brown pustules filled with dry dark brown powder, in general small (0.2 to 5 mm diameter) but sometimes they expand in depth and width; presence of cankers > Powdery scab,
- Small black or dark purple pustules (1 to 3 mm diameter) slightly raised and surrounded by slightly depressed ring> Skin spot,
- Raised dark brown to black structures called sclerotia, irregular in size and in shape, tightly attached to the periderm> Black scurf,
- Cavities up to several mm in deep and 3-6 mm in width, filled with black sclerotia> Dry core,
- Small circular holes (< 0,5 cm) surrounded by brown margins, the cavities go right into the tuber flesh> Wireworm,
- Wide circular holes (> 0,5 cm), the cavities are irregular and sometimes extended> Slug
Other pitted or raised symptoms can be encountered and are due to other biotic (viruses, fungy, pests) and abiotic causes.
