frances leacy asked 14 years ago
My British Queens & Kerrs Pinks have developed a scab, some covered 100%. The soil is dense stoneless riverbank clay. Would appreciate your opinion.
1 Answers
Gerry Daly Staff answered 6 years ago
There are two kinds of potato scab disease… common scab and powdery scab, caused by different organisms. The symptoms are very similar and while they do not usually cover the whole tuber, they can do so.
Common scab is more widspread, a disease of potatoes growing in light well-drained limy soil, while powdery scab is more common in heavy soils in a wet summer. The latter forms scabs with powdery brown spore masses.
Green organic material dug into the soil can help against the common scab, presumably by increasing acidification of the soil. Common scab can occur when land is broken out of grass.
Some varieties show a level of resistance to scab, and rotation helps to reduce damage.
