What is wong with my potatoes?

[HGKinsey]

I have raised my first crop of potatoes and have found that some of them are severely mishapen: they are lumpy and calloused. However, there are also good potatoes from the same plant. What has caused this?

[molly]

I've never grown potatoes before, but I know carrots grow misshapen when the ground is very stoney. Could this be the reason? Also, potato scab is a bacterial infection which can make the skin unsightly but won't affect the actual potato.

[norfolk boy]

I think what you are referring to is a condition in the trade called scab.This is normally caused by lack of water at various times during growing.

[molly]

Potato pests and diseases http://www.keirg.freeserve.co.uk/diary/tech/pests/potato.htm