NORTH TONAWANDA, N.Y. (WIVB)- It doesn’t look very threatening, but biologists are trying desperately to keep it out of the Great Lakes.

It’s called hydrilla, an invasive plant that can grow up to twenty feet long and if it’s allowed to take over, boats can barely get through it. That’s why the US Army Corps of Engineers has been out this week raking out hydrilla from the Erie Canal.

The Asian plant started showing up in the States fifty years ago, and was starting to take over parts of the Erie Canal, according to US Army Corps of Engineers Specialist, Michael Greer. “Last year, it would’ve looked like a very lush green carpet of almost exclusively hydrilla that was topped out to the water surface and it would’ve precluded any kind of use of the water within that area.”

It can actually push out native plants, according to Army Corps Biologist Rich Ruby. “It can change the water chemistry, It can grow so dense that it’s difficult for any boating, swimming, recreational activities.”

The goal is to keep it out of the Great Lakes, and even though it’s only a half mile from reaching the Niagara River, the Corps managed to eliminate 90% of the hyrdrilla last summer, and is controlling what’s left by pumping in an aquatic herbicide known as Aquathol K in a five mile stretch of the Canal from the Delaware Bridge to Bear Ridge Road in Pendleton.

The DEC advises against swimming there today and tomorrow because it could cause minor skin or eye irritation. The Army Corps will be using the herbicide again Wednesday, but then will be done for the rest of the summer.