Natural Root worm Remedies? This question is for a friend. Rootworm has attacked the broccoli and some...

This question is for a friend.
Rootworm has attacked the broccoli and some of the pea and bean plants within his garden. Does anyone know of an organic way of controling this pest? No chemicals please as animals own access to this garden.
Thanks for the advice.
I want to put down concrete within part...
Answers:    Here's a quick google...
http://www.gardenville-university.com/in...
but I don't own any experience in these matters.
Iris' are flowering!?
Just going on for every small critter including bugs and little rodents hate this stuff and it works!

One tablespoon of Garlic powder per pint of water. Finer garlic powder is best since it dissolves the best. Put into a spray bottle shake for several minutes and afterwards spray leaves add a drop of dish soap per pint will help the garlic fit tightly to the leaves and stay longer. After watering or a heavy rain apply more. If spray instrument gets clogged consider putting a tiny piece of nylon (from old stockings) fabric over spray bottle straw as a strainer to keep out garlic powder. Tapping bottle bottom will also help to free any clogs but the nylon or blind material works best. Attach material next to a small rubber band. Apply liberally and reapply after watering heavily or a substantial rain!