Dont even waste your time. I have been doing research in the Thibodaux wastewater wetlands for 4 years now and have watched these things spread. When I first started out there we would only see a couple patches of eggs each time out. Now, there are at least 10 patches of eggs on every tree or stump above the water. Theres literally hundreds of thousands of patches of eggs now. Them snails spread faster than mice and if you try to stop them your only wasting your time. Trust me.