Cedar Lake Conservation Club

​Annandale-Maple Lake, MN

Controlling Curly Leaf Pondweed and Eurasian Water Milfoil on Cedar Lake


Curly Leaf Pondweed (CLP) and Eurasian Water Milfoil (EWM), both aquatic invasive species, are present in Cedar Lake.   Efforts to control CLP and EWM help with water quality, sustain fish and wildlife habitat, and preserve recreational enjoyment of our lake.


Curly Leaf Pondweed (CLP)

·         CLP was first treated on Cedar in 2009. We have gone from a high in 2010 of treating 38 acres to treating 10 acres or less. CLP usually dies off in July, releasing phosphorus to the lake. Most biologists agree that a CLP control strategy is one of the steps to control phosphorus loading.

·         For the last several years, we have met our goal of 10 acres or less of CLP. 

·         To keep a watchful eye on our CLP, we have mappings done on a yearly basis. We are evaluating the results of the mapping with the DNR and our treatment vendor and will make a decision on the need to treat CLP on a year basis.

·         CLP treatment costs are paid through a Clearwater River Watershed District assessment.

·         More information can be found in the
Cedar Lake Management Plan



Eurasian Water Milfoil (EWM)

·         EWM was first treated on Cedar in 2011.  

·         An aggressive mapping and treatment strategy has been used to control the growth. The approach has kept the growth in check and kept the treatment areas manageable.

·         EWM treatment costs are paid through a Clearwater River Watershed District assessment.  

·         More information can be found in the
Cedar Lake Management Plan



Starry Stonewart Invades Wright County


Starry stonewort is an invasive species that grows rapidly, forming dense mats on the surface that interfere with recreation. The mats can be over 12 feet thick and potentially displace native species. Some scientists believe that starry stonewort is so dense that is it not suitable habitat for fish and other wildlife. It can be spread by fragments (like Eurasian water milfoil) which makes it particularly dangerous. Accidental movement by people is the most likely means of dispersal. Many of the known infestations occur in high-use waterbodies and near boat accesses.
Starry stonewort was first discovered in Minnesota in 2015 in Lake Koronis-Stearns County, about 1 hour west of Cedar Lake. The impact to Lake Koronis has been serious; treatment has been attempted to clear a path for the boat access to reduce the chance of spreading. Some progress has been made on Lake Koronis, but many areas remain infested.
In September, starry stonewort was detected in Lake Sylvia-Wright County by the DNR. This was very bad news, however the infestation was caught early. The infestation is believed to only be in the boat access area and about 0.5 acre in size.  The Lake Sylvia association worked with the DNR, Wright County Soil and Water, treatment vendors, and federal government units to quickly mobilize a treatment strategy. The DNR access on Lake Sylvia was closed on October 21, and a water screen was placed around the infestation. The starry stonewort was pulled and removed by divers with a vacuum device. Two applications of chemical (a copper sulfate product) were applied. The cost of the treatment was about $28,000.  Results of the treatment should be available in 2017.
The impact of a starry stonewort infestation makes eurasian water milfoil looks like child’s play. I’ve seen the mats at Koronis, and they look like bales of green hay; very dense and deep. This August on Koronis, there appeared to be a “turn” of the starry and the top layers decomposed, fouled the water and air, and then the lower layers quickly grew to the surface.
Detection of starry stonewort in an early infestation can be difficult as it looks very much like the “good weed” chara. We have a good amount of chara in our lake; the key difference is that starry stonewort has a different leaf configuration and the presence of the “starry” bulbils. On Cedar, we have had three different professional vendors on the lake this summer (treatment, mapping, and zebra examination) and did add to their contracts that they would also be on the look for AIS—including starry stonewort.  We plan to participate in a state-wide “Starry Search” on August 5th, 2017 which is planned by the University of Minnesota. Members of the CLCC Water Quality Committee are working at sharpening starry stonewort identification skills.
At this time, we are not aware of starry stonewort in Cedar.
The treatment of starry stonewort in Minnesota waters is still in the experimental stages. The Minnesota Aquatic Invasive Species Resource Center (MAISRC) has brought together a group of international experts to synthesize what is currently known about the ecology, impacts, and management of starry stonewort. More research needs to be done.
With the fall elections now over, it is important that our state senators and legislators understand the importance of the continuation of the state AIS Prevention funding ($10 million/year). This funding helps with the research aspect, and we in Wright County directly receive about $250,000/year for AIS prevention. Many lake people believe there needs to be stronger legislative action to address the control of AIS, which includes immediate closing of lake accesses that are identified with a starry stonewort infestation. 
Here’s a great 4 minute video on starry stonewort identification:


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