Somerset, United Kingdom

A few of my winter and spring cabbages and all my sprouts are afflicted with a wierd condition which I can't find in any of my books: many of the leaves have hard white nodules which can range from just small spots up to a few inches across. The sprout plants are stunted (some only a foot tall) while instead of spouts developing, there are largish hard hook-like lumps. I'm thinking some kind of fungal thing possibly. Any ideas?

• 10 Sep, 2014