Invasive Aquatic Plants & Treatment

2023 Invasive Aquatic Weed
on Loon Lake


By Aquatechnex


Aquatechnex performed the first round of aquatic invasive species management applications to Loon Lake on Tuesday, June 6th, 2023.


Shoreline sign notices were posted the day before treatment on Monday, June 5th to all affected properties.  These were properties adjacent to the treatment zones and within 400 feet of a treatment zone.


The first treatment of the year targeted newer invasive species called Curly Leaf Pondweed.  Half of the treatment zones on the lake were treated with the systemic herbicide Galleon SC.  There are no restrictions on water use except for a 3-day restriction on drawing water from the treatment zone to irrigate plants and turf grass.  It was safe to swim, fish, and drink potable water out of the lake immediately following treatment in all Galleon zones.  


The following link connects to the treatment zone map:

Using the above map link you can determine where we plan to apply the two different herbicides on Loon Lake and if these applications impact your lakefront. Submit questions to 509-960-8133.

Aquatechnex returned to the lake for additional Eurasian/Hybrid Milfoil treatments the following week on June 13th, 2023. 


What is it: 


Milfoil is an aggressive noxious aquatic plant invader in Washington state.  Within a few years of introduction, it forms dense mats that shade and crowd out other aquatic native plants, can alter aquatic ecosystems, degrades water quality, inhibits water flow, impacts recreational activities, and reduces habitat quality for fish, waterfowl, and other wildlife.  The dense growth also can be a hazard to swimmers and a nuisance to boaters.  


Curly-Leaf Pondweed


What is it:


Curly-leaf pondweed is a Eurasian native, which is now found nearly worldwide. It can become invasive, forming dense surface mats that choke out native plants and affect recreational uses. Since it starts growing earlier in the spring than most native pondweeds, it can often outcompete other plants. Curly-leaf pondweed reproduces by seed, rhizome, plant fragments and turions (hardened stem tips that drop to the sediment), all of which can be dispersed by water, boating equipment, or clinging to animals. It grows in still or slow-flowing, shallow to deep, freshwater. Curly-leaf pondweed is tolerant of disturbance, low light, and slightly brackish water. It grows best in cool water, going dormant as the water warms. In Washington State, curly-leaf pondweed is a C-class noxious weed. It has been found in many sites scattered around the state.



Lake Management District (LMD):


The Lake Management District was established to help with the control of milfoil and other potential aquatic and/or riparian noxious weeds.  The citizens steering committee provides advice and makes recommendations to the county as to the management and administration of the lake management district and the control of the Eurasian Milfoil, Curly-Leaf Pondweed, and other potential aquatic and/or riparian noxious weeds.


Herbicide Control:


The use of pesticides in water is regulated in Washington State. All applicators must have an aquatic endorsement on their pesticide applicators license, which is issued by the Washington Department of Agriculture. In addition, coverage under a permit issued by the Department of Ecology is required.


Loon Lake will be treated with Galleon, Aquathol K, Aquathol Super K Aquatic Herbicide, and ProcellaCOR Aquatic Herbicide.  


The applicator (AquaTechnex) will post signs in the treated and potentially affected areas no more than 48 hours prior to treatment.  The signs will describe any water use restrictions or advisories. 


Please refer to for the most up-to-date treatment information.  Treatments will not take place on weekends or holidays. 


We appreciate your cooperation while the application is taking place.    

Curly Leaf Map 2021
curly leaf 2021.jpg
JPG image [295.5 KB]
Milfoil Map 2021
milfoil 2021.jpg
JPG image [320.4 KB]
Milfoil Treatment 2021
Milfoil Treatment_2021-06-17_155102.pdf
Adobe Acrobat document [1.5 MB]

*********************************** Meeting Notices




Your Lake Needs YOU!

Consider becoming a member of the LLPOA!



Monthly Meeting


Oct. 12, 2023

6:30 p.m.


Historical Old Schoolhouse

4000 Colville Rd

Loon Lake


LLPOA Meetings are the second Thursday of each month March-Oct


Annual Meeting

June 22, 2024

10 a.m.

Old Schoolhouse

Loon Lake, WA


Email us at:


Loon Lake Property Owners Association

PO Box 165

Loon Lake, WA 99148


Annual dues

only $50 per family





Lake Management District Advisory Committee


Oct. 9, 2023

6:30 p.m.


Historical Old Schoolhouse

4000 Colville Rd, Loon Lake


LMD Meetings are held the second Monday of each month

March - Oct


For information on how Milfoil and/or Invasive Aquatic Plants impact the lake and what's being done to mitigate it, the public is encouraged to attend these informative meetings.



Upcoming Events:


Chipper Days

Saturday, Oct. 7

9 a.m. - 3 p.m.



Please check the calendar for additional upcoming events and  activities 



Visitor Counter

Get Social with Us!

Print | Sitemap
© Loon Lake Property Owners Association