Thank you for your question.

Before going down the road of applying any aquatic herbicide, please realize this is a highly regulated situation. In Minnesota, you cannot legally apply aquatic herbicides without a Department of Natural Resources (DNR) permit, or at the very least a consultation with them. This is especially true when emergent vegetation such as cattails is involved. Because of watershed and drainage issues, I don’t think that beaver ponds would be an exception. Proceed cautiously with your project without first becoming aware of all necessary rules and regulations. See the following:

https://www.dnr.state.mn.us/shorelandmgmt/apg/problemplants.html?utm_source=chatgpt.com

https://www.dnr.state.mn.us/invasives/iapm.html

https://www.dnr.state.mn.us/apm/aquatic-plant-management-permits.html?utm_source=chatgpt.com

Pope County is part of the Minnesota DNR Aquatic Plant Management (APM) program described at the above sites. I would suggest your first step should be making the following contact:

Minnesota DNR – Northwest Region Aquatic Plant Management
Bemidji Office
2115 Birchmont Beach Rd NE
Bemidji, MN 56601
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This office will be able to advise you if a permit will be needed or not. If required, they would be able to issue you this permit. You may be required to submit photos of the area surrounding the beaver pond.  There would be a cost for this permit.

There are chemical herbicides available that you might be able to use. However, due to potential liability issues and my unfamiliarity with the geographic location of this beaver pond, I am hesitant to provide you information about these herbicides. This is a matter that requires direct communication between you the DNR.

The Bemidji Office should also be able to advise you about non-chemical control measures that you would be allowed to do.

I am sorry that I am unable to provide you a direct answer to your question. Thank you for contacting our forum and for your understanding of our position.