All due respect....and no disrespect to anybody intended.....in reality, there has never been a single study done that I have seen that has shown proof of Dydimo being spread by felt-soled boots, or any other boots for that matter. Nobody knows how it is spread. There are alot of WAG's flying around out there.....from boots, to canoe paddles and wildlife. But no proof. When in fact the study pointed out could be spot-on. Maybe it's an organism that is in most waters, but one that needs a specific water condition in which to bloom? Maybe it's spread by goose crap? Maybe muskrats? Can't say no....because "nobody" knows. So why is everybody so certain that felt-soles are to blame? It's always easier to blame somoebody for something that they can't "prove" they didn't do.