Hello Kelly and all, The BTK is indeed for caterpillars and can still be found in Canada. I used to be able to buy a product called Vecto-bac which contained the BTI, and it worked like a charm. We used it once a month in our watering and never or rarely had issues with gnats. Unfortunately, some government official using their infinite wisdom decided that a person had to be a licensed pesticide user in order to buy and use the Vecto-bac? And yet there is malathion on the nursery shelves?? We can buy Aqua-bac which has the BTI in it, however it is granular and meant to be sprinkled on top of standing water where the mosquito larvae will consume it and die. I was told to soak the Aqua-bac for an hour or so and then put it in my blender and water from there. Needless to say that did not happen, and shaking the granules onto the soil of the plant and watering in did not seem to work either. Indeed, prevention is the key in controlling gnats. I'm still not sure how effective the bug zapper is, the gnats sit on the ceiling beside it?? They're easy to kill there. Also diatomaceous (sp?) earth does work, but it is slow. I did a test bag and it took 3 1/2 weeks to kill off the gnats and the larvae. That may also be more effective as preventative measures rather than fighting the battle. Now can anyone smuggle some vecto-bac across the border for me? Just kidding. Linda Foulis Okotoks, AB Canada