I have had no luck with copper wire. It is also expensive. For both slugs and snails I have had great success with a combination of crushed egg shells around the base of the plants and shallow pans with cheap beer or a yeast and water mixture. Slugs and snails are attracted to yeast. They crawl into the pan of beer and die happy.
Elizabeth - or Your Majesty
Living and growing in Lafayette, La.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant. ~Author Unknown