Apple cider vinegar attracts them too. I put a yellow sticky gnat tape around a yogurt cup and fill it with the apple cider vinegar. It catches hundreds. The tape is sticky on both sides. It even catches flies. I have had to replace the tape in a week, because it was so covered with gnats and flies. ACV works great. I use the generic kind. I bought the yellow tape from Amazon and cut the take in half done the yogurt cup was only 6oz. It gives me more tape as well. Side note, I use small pieces of duct tape to secure the yellow sticky tape to the cup because it tends to slide down the cup a little. And because it's a round cup, without the duct tape, the stiff yellow sticky tape wants to come undone. But duct tape holds it good.
