Where I live in central pa is nowhere near any didymo affected water. If a duck was to fly here from the nearest water containing didymo, he would certainly be dried off before he got here.

The only way didymo could make it here today would be through people. It's not unlikely that someone would fish the gunpowder in Maryland and one of the popular creeks in my area within the same weekend . Wading boots don't dry in one days time and could still spread it here after a day or two. A duck, on the other hand is not likely going to visit the gunpowder and the little J in the same day. I guess my point is, if it spreads here today the culprit probably didn't have wings.

Here's some pics of various  stages. As far as wet ducks, it would be nice to think they are dried out when migrate and they land in their next waterway. But these are tiny little critters... Lets hope for the best...

BTW: Since it's in the Delaware River, (upper branches), It's not going to be too long before we get it locally. I guess I'll be bleaching my stuff from when I fish there  from now on...
 
EDIT: Neat video in this link. http://www.invasivespeciesinfo.gov/aquatics/didymo.shtml

Interesting site KJ. A lot of info. Nice to see a research study on it.
 
I wonder if they, manufacturers of felts, ever though of making felts in a more coarse design. Something that disinfectants can penetrate bettter. Or even a felt with a micro fiber that would pierce the cell wall of the algea when walked on.