What do you use to combat root maggots? I used to use diazinon, but that's now off the market. Last year I tried wood ashes with good success, but this year I've had maggots in the cabbage in spite of the wood ashes. I put some Reemay fabric over one row of cabbage, and so far it looks like most of the cabbages under it are doing OK, though I've lost a couple. What works for you??