We, the undersigned, submit this petition to immediately halt the continued and future chemical treatment of invasive aquatic vegetation on Lake Minnetonka due to the long-term degradation of the lake’s fisheries, aquatic habitat, and ecological stability.

There are a number of associations (LMA, LIDs, etc.) promoting a extensive chemical treatment plan for Lake Minnetonka. 

The Lake Minnetonka Association currently oversees treatments on a number of bays which are managed by Lake Improvement Districts (LIDs) created by lakeshore residents to pay for these treatments. 

The goal of these associations are to chemically sterilize our lake to offer clear water for docks and weedless shorelines. In doing so, they will collapse an entire fishery and create a weakened ecosystem for generations to come.

The Chemicals Being Sprayed Do Not Just Specifically Target Invesive Weeds, But Native Weeds As Well.

Chemicals Used in Curlyleaf Pondweed Treatment & Eurasian Watermilfoil & Their Impacts

Lake Minnetonka’s chemical treatments commonly rely on the following herbicides:

Diquat Dibromide (e.g. Reward):

• Non-selective contact herbicide.
• Destroys ALL submerged vegetation it contacts, including native species critical to fish habitat.
• Causes oxygen depletion during plant decay, leading to fish stress and invertebrate loss.
• Banned in Europe under EU pesticide regulations due to aquatic toxicity and long-term ecosystem risks.

ProcellaCOR (“Forever Chemical”):

• This chemical class is not fully understood in long-term enviromental studies and human health effects
• A newer cheical that may never fully breakdown and build up in the enviroment
• Multiple independent researchers openly stated this chemical needs long-term cancer and endoctrine disruption studies that have not yet been completed

Endothall (e.g. Aquathol K, Hydrothol 191):

• Non-selective contact herbicide.
• Toxic to certain fish and invertebrates at elevated concentrations.
• Contributes to sediment oxygen depletion and nutrient cycling disruptions.
• Highly restricted in many international jurisdictions due to ecological concerns.

Fluridone (e.g. Sonar):                                 

• Systemic herbicide that inhibits pigment production.
• Can suppress both invasive and native plant regrowth.
• Long persistence in water columns (weeks to months), interfering with plant community balance.
• Under review or banned for certain uses in several EU member states.

Chemical Concerns: EU Regulatory Comparison

• Diquat is banned in Europe (since 2018) due to high aquatic toxicity and long-term ecosystem risks.
• Endothall is restricted or banned in EU jurisdictions for similar concerns over fish and invertebrate impacts.
• Fluridone and 2,4-D face tightening regulations or limited approval in parts of Europe due to persistence and ecological concerns.  

The Fishery and Ecology of Lake Minnetonka are not Renewable once Collapsed. 

These systems do not recover on political timelines, and no chemical program can replace natural biological stability once lost. Continued reliance on broad-scale chemical vegetation removal is incompatible with the preservation of Lake Minnetonka’s fishery, economy, and legacy.

The Management Shift Happening on Lake Minnetonka: Targeted Control to Blanket Bay Spraying

For years, invasive plant management on Lake Minnetonka followed a targeted approach.

Now, a Major Shift is Underway:

These associations are pushing for full-bay (or near full bay), blanket chemical spraying.

• Their goal: Suppress invasive growth before it starts, under the claim of “preserving legacy homes.”
• This approach applies chemicals across entire bays, not just problem areas.

The Risks of Blanket Spraying:

• Kills beneficial native plants critical to fish habitat.
• Disrupts spawning areas for fish.
• Increases risk of chemical-resistant hybrid invasive species.
• Alters oxygen levels and water clarity.
• Impacts forage fish and juvenile fish survival.
• Long-term buildup of chemical compounds in the water column and sediment.

Lake Minnetonka is a Public Body of Water. 
These associations have no right to be making large scale decisions on behalf of the public that has a devastating impact on it’s fisheries and ecosystem. A select group of people should not be allowed to have this much authority to operate and control a public body of water at this level. 

LIDs are already being passed. Every bay in Orono will be governed by a private group now. These sprays are scheduled and happening.

We call on all regulatory agencies, lake associations, and elected officials to immediately suspend further chemical treatments and to adopt alternative, habitat-first management for the future of Lake Minnetonka.