Solutions to Invasive Apple Snails

Question: What are some ways to address the problem of invasive apple snails in the United States?

Answer: The market is kind of reacting to this problem. Obviously prevention is the best policy. Early identification seems to be the trick. If you can get ahead of the population of snails before they really get established and are taking off, then that’s the best opportunity. SePRO Corporation has come out with a product now that’s labeled for control of snails and it’s called Natrix, which is a copper-based product that we’ve used in almost all of those states that I named—South Carolina, Mississippi, and Georgia. And that product is applied to the water, and it actively kills the snails. It generally is applied at a .3 part-per-million; relatively inexpensive, but when you look at that you have to make that application multiple times over several years to actually eradicate the snail in that particular area, it can be fairly expensive. Some other techniques that have been used is removing the vegetation that the snail requires for its egg laying, because it has to lay its eggs on a surface above the water line. So if you’ve got cattails or phragmites or any of the emergent vegetation that’s above the water line, if you de-vegetate that entire area then you remove their breeding site. So we’ve gone through on several properties, and we do a herbicide treatment on the cattails, physically remove the cattails so that there’s nothing above the water line, and you’re limiting where they can reproduce. We’ve even done MSO or methylated seed oil treatment on the actual egg sacks itself, so that we can go through two or three times a year and do treatments on the egg sacks, which will kill the egg sacks. So you’re kind of proactively going after their production cycle.

Another option that we’ve been doing is stocking those waterways with shellcracker. Shellcracker is a brim species of fish that feeds on basically snails, so we’re kind of going at it in a multi-prong way: physical removal of the snails when you see them, physical removal of the eggs when you see them, mechanical control by cutting out all the cattails or any emergent vegetation that they can grow on, biological control by stocking shellcracker, and then the chemical option which is MSO treatment on the egg sacks and Natrix treatment for the actual adult snails. So, now there is a tool set and ability to actually go after this problem, and we’ve done a couple of different case studies, one particularly with Alabama Department of Natural Resources, which was kind of co-funded by the U.S. Fish and Wildlife Service and we’re starting to develop the research, the infield treatment and then the data associated with those treatments and how effective those methods are, and we’re getting to the point where we’re making headway with this.