I read that, too. But the article also says:
"...and he says he doesn't regret concluding that anglers were spreading didymo from stream to stream.
He goes on to say:
"There are a lot of diseases and things that can be spread that way."
What's interesting is what follows:
And don't think simply switching to sticky rubber boots solves the problem, says Bob Wiltshire, executive director of the Invasive Species Action Network in Livingston, Montana.
"There is no doubt that someone with rubber boots that are not clean poses a greater risk than someone with felt soles who has cleaned," Wiltshire says. "Cleaning is the most important thing for everyone."
It is just me or does it bother anyone else that because some "expert" has a theory and writes an article condemning the use of something without having thoroughly researched other potential causes, it resulted in unneeded, knee-jerk legislation (like we don't have enough of that already), and caused a bunch of responsible fisherman to have to fork out more of their hard-earned money, both of which had a negligible - if any - effect on the original issue?