As Wendy mentioned above, Sluggo works well and I am pretty sure its organic which I prefer around my food crops. I believe it works by suppressing their appetite so they go into a hidey hole and don't come out again. Regardless, unlike some other slug baits I have used in the past it doesn't leave melting slugs all over the place.
If you are really interested in expanding your ecosystem, get a few female ducks, they will take care of your snail problem, fertilize your bananas and provide breakfast. Win, win win - oh, they might do a little digging in your garden
