I had these savoy cabbages covered with garden fleece, but not very well. ​

Cabbage moths got in and laid thousands of eggs that developed into cabbage worms, which I didn’t notice under the fleece.

High time to get out the BT (bacillus thuringiensis) and do some spraying. If It works the cabbages can make a comeback.  

This is an old story that repeats itself every year. For many years I didn’t even try to grow brassicas, but the last few I’ve been trying many ecological methods of pest control like fleece, wire netting and BT with quite a bit of success.