Is there anything more disgusting than maggots? Hate those pests. And this year, we have problems with them in our onions. It's been cold and wet, ideal conditions for them. We probably should have rotated the onion crops, but we didn't. It is impossible to get rid of them now.
The Weekend Gardener has an extensive discussion on these nasty critters. Check out the site. This photo is from that e-mag and there are more good images of the disgusting creatures.
My DH has decided to grow onions in a container for this year instead of planting them in our ground. He will have to do some work on the soil to get rid of the maggots.