SHOREWOOD, Minn. (AP) - The Minnesota Department of Natural Resources hopes to deliver the killing blow to zebra mussels discovered in a small Minneapolis-area lake.

The agency and its contractor will inject potash under the ice of Christmas Lake Tuesday.

Officials say it's the first time potash has been used for this purpose in Minnesota and only the third time in the U.S.

Potash is a potassium compound often used in agriculture and industry. The potash application is a follow-up to earlier treatments with the bacteria-based pesticide Zequanox and copper.

The DNR says if the application succeeds, it will be the first time zebra mussels have been eradicated from a Minnesota lake.

The invasive pest crowds out native mussels and competes with other animals for food. They're also a nuisance to boaters and swimmers.