Over the years I've tried everything to keep the cabbage white off my Brassicas without success. So I've given up with brassicas and concentrate on more rewarding crops like potatoes, broad beans, runner beans, onoins, garlic, peas, sweet corn and leeks. My globe artichokes have been great for 10 years, but did not corp well this year despite vigourous plant growth. I've left them in the same bed without any supplementary food. Any ideas?