Eurasian Milfoil is the Chippewa Valley's number one invasive specie.

"Mainly because people don't clean their boats. That's now it spreads, yeah,” says DNR Deputy Warden Justin Wershofen. "My main mission is to educate boaters and enforce all invasive species laws."

Justin spends his days perusing boat landings, looking for dirty boats.

"We want to make sure that all vegetation gets off so that it doesn't make it to another body of water,” he says.

Which is just how the Eurasian Milfoil made it to the Chippewa River, clogging parts of the water way and taking some fun away from boaters.

Wershofen says Eurasian Milfoil is especially bad for boaters since it grows fast and it grows long, making it easy for boat props to get caught up in it.

"It's kind of a totally worthless piece of lake right now,” he says.

The plant grows about two inches a day and can reach lengths of 20 feet.

"As the plants come to the surface they tend to go and start growing across the tops of the surface,” Wershofen says.

Which is just what Mike Ries says happened near his family’s cabin on Little Green Lake.

"You couldn't take a motor boat through the weeds without raising the motor up numerous times to clean the weeds off, you couldn't water ski, you couldn't enjoy fishing cause you couldn't get the line in the water,” says Ries.

So he has advice for boaters.

"If anybody's out boating just make certain that the boat and trailer's clean when you get out of the water. So the next time they go in they're not spreading the disease. And that's what I consider it. It's hard to get rid of once it's here,” he says.

Wershofen says the best way to clean your boat is by washing it with diluted bleach...1/2 cup of bleach to 5 gallons of water.

"You just go ahead and rinse down your boat, hulls, every part that makes contact with the water,” he says.

And if Wershofen spots your boat and it's not clean...

"There can be penalties of anywhere from $150 fine upwards of well over $200."