Root maggot infestations can be prevented by covering the seedbed with a cheesecloth or screen covering placed immediately after seeds are sown. Covering should extend at least 6 inches on either side of the seed row. A square of tar paper (3 to 4 inches wide), or other sturdy material, placed at the base of each transplant will prevent adult cabbage maggots from laying eggs around stems. Cones made of window screen and placed over individual transplants will also prevent attack by cabbage maggots and have the advantage of being usable in subsequent years.

Organic/Biological Control:
Dust plants with diatomaceous earth. Rove beetles are predaceous on root maggots.

Cover seedbeds with floating row covers immediately after seeds are sown to prevent infestation. Be sure the cover extends at least 6 inches on each side of the seed rows.

Heavy paper collars or other sturdy material may be placed around the base of transplants to prevent egg laying around stems.

Applying beneficial nematodes in seed furrows or as a top dressing around plants can be effective in controlling the larvae.

Jleiwig, I found this information as well. I suppose I should have been more specific. I know I can't save the plants now, and floating row covers are no good now once the infestation has set in, but is there a way to amend the soil now so that I can still plant in the beds without completely emptying them or waiting for next year to roll around/ Will adding diatomaceous earth to the soil now do enough for me to plant again soon?

I think diatomaceous earth in in liberal amounts would do the trick. They use to use lead-arsenic, but they took it off the market years ago.

John

Here is a link that might be useful: Johns Journal

I dug out the holes where I pulled up the infested plants and worked in the DE. I also unburried as much of the root system of the other broccoli and put some around there before I filled back up the hole. I went ahead and dusted the carrots and radishes for goodness knows I'm sure they're on their way. Think I stand a chance with just this or should I dig out the whole bed and work it in?