Little St. Germain Lake Protection and Rehabilitation District

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Invasive Aquatic Plants on Little St. Germain Lake:

Plant Management – Chemical Treatment 2026

2026 Chemical Permit Application for Treatment of the Eurasian Water Milfoil

A Breif History of AIS Management:

In the early 2000s, lake users began noticing thick weed growth in East and No Fish bays. By 2002, the Wisconsin DNR identified the culprit as Curly-leaf pondweed (CLP)—an aggressive, non-native plant. Then in 2003, Eurasian watermilfoil (EWM) was also discovered in West Bay, near the public boat landing.

Both species are known to spread rapidly and disrupt lake ecosystems and recreation. At the time, effective control strategies for northern Wisconsin lakes were limited.

Lake leaders at the time prepared and executed strategies to address the problem, which have helped manage the invasive species for the past several decades.

🛠️ The Initial Response

Led by: John Manki (part-time resident)
Plan Created: 2003
Implemented: May 2004

Key Elements:

  • 5-year herbicide treatment plan
  • Annual monitoring by trained lake volunteers
  • DNR-approved and county-supported
  • Funding:
    • $120,000 DNR grant
    • $120,000 from lake district and local sources

📈 What Happened Next?

✅ Curly-leaf Pondweed (CLP)

  • Responded well to early treatments
  • Surface mats disappeared
  • Still present, but at low levels
  • Continued annual management needed

Get general info about CLP HERE

Curly Leaf Pond Weed (Source: USDA)
Curly Leaf Pond Weed (Source: USDA)

⚠️ Eurasian Watermilfoil (EWM)

  • Spread to every bay despite efforts
  • Very difficult to eradicate
  • Now managed below nuisance levels
  • Most lake users don’t notice its presence

Get general info about EWM HERE

Euasian Watermilfoil (Source: WDNR)
Euasian Watermilfoil (Source: WDNR)

On-Going Management

The original plan has been revised annually as experience and new data shaped better strategies. A professional lake consultant, Onterra, LLC, joined the team to help develop a long-term plan beginning in 2009. Additional grant funding has been pursued to continue managing these invasive species.

Proposed treatment sites are based on survey work accomplished during the previous summer and fall. The maps reflect what are likely to be the actual sites to be treated the following spring, but all sites will be verified by a professional lake management consultant prior to the finalizing treatment sites.

For more information on treatments applied the last few years follow these links. A complete history is archived HERE.