AUGUSTA – By a 31-3 vote, the state Senate gave final approval Tuesday to a bill to launch a mandatory sticker program aimed at preventing invasive plant species from getting into Maine lakes.

Gov. Angus King is expected to sign the bill, spokesman John Ripley said.

The law will require special stickers on all powerboats before they are used in Maine’s lakes and other inland waters. Stickers would cost $10 for boats registered in Maine and $20 for those registered in other states.

The sticker program begins Jan. 1.

Money collected from the sticker sales would help to pay for the war against invasive plants, especially milfoil, which destroys lake fisheries, boating and swimming. Large fines would be imposed for launching boats carrying parts of invasive plants.

A campaign is under way to encourage boaters to inspect their vessels, trailers and fishing gear and remove stray plant matter.

As refined by lawmakers, the bill includes provisions to make sure enforcement is not too heavy-handed. If a boater is found with other violations, no fine will be issued for not having a sticker.

Boats being towed through the state do not need stickers. Stickers are required only when the boat is used in the water.