A photo from Boisvert’s report that shows purple Loosestrife being removed by members from the Mudhen Lake Association. Larger populations of Purple Loosestrife are often removed by Galerucella beetles.

Burnett County has always worked diligently to educate, prevent and control aquatic invasive species (AIS) within the county. Some of the common AIS in Burnett County that the county is trying to control are Zebra Mussels, Purple Loosestrife and Yellow Iris.

At the Natural Resources Committee meeting, Thomas Boisvert, AIS Coordinator, presented his 2020 annual report on AIS in the county. It states in his report that Zebra Mussels were first discovered in the county in 2016 in Big McKenzie Lake, and one year later, in Middle McKenzie Lake. In 2016, both Burnett and Washburn Counties applied for a rapid response grant to help take control of the Mussels. The grant was awarded by the Wisconsin DNR and was used to purchase supplies and materials to help control the spread of the Zebra Mussels such as decontamination stations, monitoring equipment and supplies and other outreach materials.

Boisvert’s report states that Zebra Mussels plate samplers were placed in both McKenzie Lakes in order to help monitor the growth of the Mussel’s population every year. Looking at the 2020 results, the population in both McKenzie Lakes continues to climb. Plate samplers have also been placed in other lakes throughout the county to make sure Zebra Muscles do not enter the lakes, and so far, Big and Middle McKenzie remain the only two lakes within Washburn and Burnett County that contain Zebra Muscles.

Purple Loosestrife

According to Boisvert’s report, biocontrol continues to be the most successful form of Purple Loosestrife control. In 2020, the biocontrol program proved to be very successful. The Burnett County AIS Program raises and releases Galerucella beetles on the Loosestrife as part of this biocontrol program. Boisvert’s report states:

“There were three mass rearing cages that were used in 2020: Siren School cage sponsored by Burnett County, Crex Meadows cage sponsored by WDNR, and a cage sponsored by the St. Croix Tribe. In total, this collaborative effort released nearly 40,000 Galerucella beetles into highly infested areas of Purple Loosestrife.”


Yellow Iris is a very pretty plant to see around a lake, but it’s actually an aquatic invasive species that prevents other plants from growing.

When there are smaller populations of Loosestrife, a manual removal process is typically used, and when there are moderate sites with no beetle damage present, chemical treatments are used (approved aquatic herbicides).

In 2020, the Burnett County AIS Program, with the help of Associated Lake Associations, was able to control Purple Loosestrife on North Sand Lake, Long Lake, Des Moines Lake and Mudhen Lake.

The plan is to use beetles again in 2021 to supplement the other control efforts in the county.

Yellow Iris

Yellow Iris never used to be a big AIS problem within the county, but now unfortunately, the county is beginning to record occurrences of the Iris more often. The report states:

“Due to increased monitoring, Yellow Iris is now being observed on some Burnett County inland lakes. Big McGraw has the most notable population within Burnett County. Big McGraw Lake shares a northern border with Douglas County which makes this issue a concern for Douglas County’s AIS program as well.”

During the meeting, one of the supervisors asked Boisvert how the Yellow Iris got to the Lake. Boisvert responded by saying it got there by someone planting it.

He said, “It is very pretty, it’s a nice ornamental looking plant and that’s how it got there- someone thought it was pretty, but it’s a wetland invasive.” He explained that it will get into a wetland and then will be the only thing that will grow there.

They are going to combat the problem on Big McGraw Lake by contacting the landowners this year via the mail to inform them about the Yellow Iris and the dangers that it poses to the lake. They will encourage the landowners to remove the plant and assistance will be given if needed. They hope that with landowners working together with Burnett and Douglas County Conservation Departments, there will be a noticeable impact on the Yellow Iris population on the lake in the future.

Clean Boats, Clean Waters

The Clean Boats, Clean Waters (CBCW) program had a successful season in 2020, despite COVID-19. Two AIS interns and one contracted employee made up the team for this year and was able to go between most of the landings.

Boisvert’s report shows that 2,341 boats were inspected and 4,962 people were contacted as of Dec. 2020. As high as those numbers seem, they are less than average compared to previous years due to the COVID-10 pandemic. According to the report, 2020 was a successful year, and 2021 should also be successful, building upon 2020’s season.