To get rid of them you can do a lot of things like either use a NO pest strip, neem oil or putting sand on the surface of the soil will suffocate the eggs and get rid of them as well. Tobacco juice kills them, and works well for re-occurrences!
They can be in or on the soil and can fly. In order to get rid of them you can use neem oil, sand on the surface again kills them, and no pest strips catch the ones that fly.
Some info I came across when I had a problem a while ago, cant remember who wrote it sorry, I dont suppose they will mind as it's all for a good cause.