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Eurasian Watermilfoil control: 2024 update

Under contract to the CLWA, Clear Water Lake Management, with drone assistance from Zero Gravity Aerial, completed a treatment of invasive EWM in Crystal Lake on September 17, 2024.

The estimate of EWM infestation is now down to 1.7-1.8 acres. The team used ProcellaCOR on the east end of the lake and 2,4D for the rest of the sites. ProcellaCOR is a newer product, more expensive but more effective and dissipates more quickly in the water body. Zero Gravity reports the south side of the lake responded well to last year’s dose. On the east end several of the sites heavily involved with plants three years ago now have only isolated single stalks of EWM remaining. The one area of concern is around 3rd St. on the Beulah shore that has not responded as well. If it persists CLWA may need to test for hybrid strains of milfoil.

In 2021, the first year of treatment, the CLWA team carried out two treatments with 2,4D on approximately 7 acres of EWM infestation, including very heavy growth at the east end of the lake, centered around the Beulah Launch site and swim area where it was undoubtedly introduced by recreational boats. An inspection of regrowth in mid-June 2022 showed that the extent (footprint) of the plant had decreased to 5 acres and that the biomass was now very sparse – a footprint reduction of almost 30% and a biomass reduction of 90%. These results reflected a high rate of success.

Due to these positive results, only one annual treatment has been needed in subsequent years. Since 2021 CLWA has treated 4 times with the herbicides 2,4D and ProcellaCOR. Interventions in future years will be subject to continued monitoring and evaluation.

Although invasive species, once established, never completely go away with any treatment, we are left with a manageable smaller remnant to control in the future. Using Zero Gravity Aerial’s drone surveillance with Clear Water Lake Management’s application boat gives excellent accuracy in placement of the herbicide with reduced chance of missing plants and excessive product use.

We will continue to treat once a year instead of twice per year since control has been achieved. This is consistent with CLWA’s goal of using only the absolute minimal treatment.

This work is authorized by the Michigan Department of Environment, Great Lakes, and Energy under Aquatic Nuisance Control Permit No. ANC9805924.

If you have questions, see FAQs about Eurasian Watermilfoil.

 

Protecting Crystal Lake Now for Generations to Come.

P.O. Box 89 • Beulah, MI 49617
info@crystallakewatershed.org
231.882.4001 Tel

The Crystal Lake Watershed Association (CLWA), is a non-profit (501c3) organization.

Photography: Jay Burt and Rick Cosaro

Site by: Rick Cosaro

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