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In the Media

Submission of Permit Application to control Eurasian Watermilfoil

Posted Tuesday, March 10, 2020
— In the Media, Milfoil

March 10, 2020


CONTACT:  Chris Conant

                      President, Lake Iroquois Association




The Lake Iroquois Association  (LIA) and the Lake Iroquois Recreation District (LIRD) have jointly applied to the Vermont Department of Environmental Conservation (DEC) for an Aquatic Nuisance Control Permit to use the aquatic herbicide, ProcellaCOR (active ingredient Florpyrauxifen-benzyl), to control the infestation of the invasive weed, Eurasaian Watermilfoil (EWM) in Lake Iroquois.  ProcellaCOR is an herbicide that specifically targets EWM.  It has received a Reduced Risk classification.  Studies show that it does not cause adverse effects on human health or the environment.  It targets the plant’s growth receptor and is very effective at eliminating EWM when used at very low concentrations.  It breaks down very quickly – within hours.

The Vermont Department of Health has thoroughly examined this product and, in 2019 its use was approved by the Vermont DEC in 4 lakes in Vermont. The result of this application was almost immediate, with significant plant deterioration occurring within days of the herbicide application.  There were no deleterious effects on native aquatic species and the herbicide was shown to dissipate in less than 24 hours.

The permit application filed by LIA and LIRD includes a comprehensive lake management plan with herbicide treatment as part of a multi-pronged effort to reduce and control the EWM infestation.  The plan includes continuation of the many other projects the LIA undertakes to enhance the lake’s water quality.  Herbicide treatment would be targeted to EWM and limited to 40% of the littoral zone (the area of the lake where plants can grow).  The littoral zone of Lake Iroquois comprises approximately 100 acres, so treatment would be of about 40 acres at the north end of the lake where the infestation is so dense that boats cannot navigate through it.

The EWM infestation in Lake Iroquois has long been a problem.  It has been spreading and has caused a reduction of native aquatic species to the point that EWM is now the most commonly found plant in the lake. The LIA has undertaken numerous projects that have reduced nutrient levels and sediment runoff in the lake, improving water quality.  LIA provides information and educational materials to lakefront property owners about lake-friendly landscaping and creation of buffers to help reduce runoff from lawns and gardens.   LIA runs a greeter and pressurized hot-water boat wash station and has used Diver-Assisted Suction Harvesting (DASH) of milfoil, and placement of bottom barriers to help reduce EWM.  All of these are important aspects of the comprehensive lake management plan but have not been sufficient to control the EWM infestation.  The addition of this targeted herbicide provides a means to reduce and control the infestation allowing native aquatic plants to re-populate and mechanical methods to be effectively deployed.

The complete permit application, the detailed comprehensive lake management plan, recent aquatic plant surveys, further information on ProcellaCOR, the notice that was sent to lakefront property owners and property owners bordering waterbodies for one mile downstream along with information on how to follow the permitting process can all be found on the LIA website: