There's a super TV programme called DASH village. Each week the stars of Japan's pop sensation TOKIO, renovate an old farm and have an expert guest attend.
The site is in Japanese, but I think worth a look.
http://www.ntv.co.jp/dash/village/
I saw them spraying milk on the leaves of their brassicas. I assumed that it was to counter the caterpillars, given the state of the leaves. Having looked this up on the internet, like seems more likely it was fungal control. Spraying clay to combat caterpillars was mentioned a few times.
I should add, I enjoyed the cabbage last night. I used to hate cabbge.
