Plant in a different bed than the previous year and, then, put row cover over the planting.

I am dealing with these guys right now. According to one source I spoke to, sacrificial aromatics will attract them away fro your crops, and they recommended mint because they prefer tender, thin leaves and shoots. I have just tried spreading Diatomaceous earth over the soil around my young seedlings to see if that helps. They are clipping off the cucumber plants at the base, and munching on the pea seedling leaves.

I had them on my tomatoes this spring. I know it's NOT organic, but 1 spray of Melathion eliminated them in a few hours...