Status and Plans for Control of Aquatic Invasive Species (AIS) in LCO and Little LCO – May 2024
Status of AIS spread: In 2022, slightly over 50 acres of Eurasian Water Milfoil (EWM) and less than 2 acres of Curly Leaf Pondweed (CLP) were surveyed and mapped in the two lakes. EWM has exploded from basically nothing from a few short years ago. In 2023, we mapped 68 acres of EWM and only small amounts of CLP. Maps of the EWM infested areas surveyed in 2023 are located here: https://static1.squarespace.com/static/589d2006ebbd1a9c437fd84a/t/65fef729a46d9a1f8f3de8c4/1711208238216/2023+AIS+Total+Map+Set+lr.pdf
Status of 2023 treatments: There was chemical treatment using Diquat herbicide in Chicago Bay and Anchor Bay areas for EWM in 2023. Late 2023 inspections indicated that growth was growing back. 2023 treatments on the NE shore of Little LCO and Snowshoe Bay using 2,4-D Amine herbicide was reported as a positive reduction, although inspections are needed this spring to verify. The Eco Harvester was used on approximately 5 acres in the early season when it appears most effective and has reduced natural fragmentation.
The Plan for control in 2024:
● Prevention measures are important to stop the spread of AIS. 1) We will maintain a “Clean Boat, Clean Water” boat launch monitor and the camera at the Chicago Bay DNR landing in 2024. 2) Additional signage has been proposed for all 3 public landings that will encourage self-inspections for AIS before and after launch. We are awaiting DNR approval to post the signage. 3) Additionally, we encourage boaters to be aware of where AIS is on the lake. Read the maps above. Avoid driving your watercraft through these areas as fragments from propellers spread AIS. Tell your visitors about the problem so that they will avoid them as well.
● Identify new areas of AIS. This is an “all hands” needed exercise. We encourage all lake users to know where AIS is now, but also be on the lookout for new beds of AIS in the lake and report it. If we know where it is, we can take steps to either treat it or use measures to stop its spread as mentioned above. You can report it by using the lake observation form here: https://docs.google.com/forms/d/e/1FAIpQLSdqTguR-z5N-UBxqLPHU9eaHwTF7V5l-UXiYzVp80wCLqRgfw/viewform or by emailing COLA communications at communications@cola-wi.org. Include GPS coordinates if possible. If you are not sure if an observation is a new bed or an old one, report it anyways.
● Proposed targeted herbicide treatment areas are listed below. These areas were recently approved by WDNR for herbicide treatments. Pre-inspections of the areas must yet occur which would change the plans for herbicide treatments.
~ These treatment activities will most likely occur in June to late July.
~ We have recently notified property owners that are within 200 feet of herbicide treatments via US mail. Only those owners received the letter.
~ Additionally, prior to herbicide treatments, signage will be posted along shorelines and landing alerting nearby homeowners of treatment dates and any temporary water use restrictions. Water restrictions vary by herbicide used and may temporarily affect your use of the water for drinking, fishing, swimming and irrigation. These restrictions are listed on the DNR chemical fact sheet located here. As weather is a factor in effective treatment, the exact treatment date may vary by a day or two. Email blasts will also be sent announcing pending treatments. Sign up for email blasts that will communicate the most current treatment plans and more exact treatment dates. See the COLA website to sign up or email communications@cola-wi.org.
~ In Little LCO, we were approved for the herbicide 2,4-D. When applying for the permits, we alternatively proposed the use of Procellacor EC herbicide, a chemical most commonly used by many lakes with success. Procellacor was again denied in 2024, as in the past, due to the chemical label problems related to use on lakes with irrigated crops and/or wild rice. Additionally, DNR has restricted our treatment areas to approximately 8 acres in Little LCO and denied additional acreages (on the west shores and to the south) in caution for concern for the wild rice. (DNR enforced the same size restriction in 2023).
~ In Big LCO, we have approval of using the herbicide 2,4-D Amine this year. In 2023, we used the herbicide Diquat on recommendations by experts. The WDNR has disallowed Diquat in 2024 because Big LCO has farm irrigation using the lake water which the WDNR has ruled not allowed. Diquat requires a 5 day waiting period before any irrigation, which in 2023 became an issue with the local farmers that limited their irrigation capabilities and other issues. That said, Diquat, at the allowed concentrations, is believed to have been inadequate in treatment.
Our preferred herbicide is Procellacor which is disallowed due to “which by some'' is perceived to be a mislabeled labeling problem. We have had communications about this incorrect labeling issue with the manufacturer and WDNR. We do not expect timely positive re-labeling, if it will happen, or know if a re-labeling will allow the use as it is under the Department of AG control. 2,4-D Amine does have some restrictions for irrigated water, but our targeted spots have adequate distance that are allowed. All said, we believe we had good results with 2,4-D Amine in Little LCO, a systemic chemical, meaning less harm to the natives, so this is a reasonably good alternative. Again, pre-inspections of last year's growth may change treatment plans.
● Mechanical Treatment: Smaller patches and areas of spread concern in both lakes will be harvested mechanically with our Eco-Harvester machine, possibly by divers, or remain untreated. We have applied for and recently been awarded permits for mechanical harvesting. We applied for many areas to allow us maximum flexibility in choosing which areas to harvest. Most likely, the total harvest will be below 10 acres. The final areas that will be harvested will partially depend on what areas are awarded chemical permits. Particular areas of harvesting that are being considered are 1) Near boat landings, 2) NW of Moccasin Bar, out from Anglers where herbicide treatment likely will not be allowed and boat traffic is high, 3) Near docks on Barbertown Bay where boat traffic is high, 4) Little LCO areas, some as a precursor to herbicide treatment, and other small areas that make sense and we have time for.
● Divers/DASH (diver assisted suction harvesting): We have a desire to have a small pilot project of diver harvesting AIS. Some lakes have reported good results, others have not. The process is very labor intensive by skilled labor using special equipment and relatively slow, so it is rather expensive. Determination of the area to harvest, getting cost estimates, gaining knowledge, and obtaining a vendor have been slow and delayed our progress.
● Manual harvesting by homeowners is encouraged especially near docks and lifts. Manual harvesting is allowed under some constraints. See website for tips: https://www.cola-wi.org/manual-removal-of-ais. Remember to harvest only AIS, not natives, and clean up weed fragments. Harvesting natives is restricted to small areas.
If additional information is desired about the treatment plans or you have other questions regarding COLA, please contact COLA at communications@cola-wi.org. Please consider donating or volunteering to help protect our lakes! Opportunities to do so can be found on COLA website cola-wi.org.