Barriers have been placed in the lake.  The barriers, purchased last week by Flathead County, consist of a heavy, black liner material attached to PVC pipes that are filled with sand to stay on the lake bottom. The barriers will stay in place until next spring when divers will return to the water to remove the weed.

If left untreated, milfoil forms dense mats of vegetation on the surface of the water that may  interfere with recreational activities such as fishing, swimming, and boating. The resulting effect can be a decrease in lakefront property values.  EWM reproduces successfully and very rapidly, making it a threat to any water body it invades.

Pieces of plants are easily transported between water bodies by boats and fishing gear.  Anyone who has fished or boated in Beaver Lake must clean their boats, equipment and waders prior to entering another water body. Please contact Fish Wildlife and Parks (FWP) in Kalispell at 444-2449 if non-decontaminated equipment was taken from Beaver Lake to any other lake so those locations can be monitored. FWP has a decontamination station and a brochure listing approved car washes.

Visit our EWM weed ID page or library for more information.

• Hydrilla – priority class 1
• Eurasian Water Milfoil – priority class 3
• Curly Leaf Pondweed – priority class 4
• Flowering Rush – priority class 4
• Purple Loosestife – priority class 4
• Saltcedar – priority class 4
• Yellowflag Iris – priority class 4

For more information about the priority classes  for FWP’s  Aquatic Nuisance Species visit their website.

January’s Monthly Weed Post features Eurasian Watermilfoil.  Did you know in 2010 that EWM was found in six additional counties.   Download the monthly post and in just a few minutes be up to date on EWM.

 Concerns  Milfoil forms very dense mats of vegetation on the surface of water, which drastically changes the ecology of the body of water.  It interferes with recreational water activities such as swimming, water skiing, boating, and fishing.  The mass of vegetation created by this plant can cause flooding and it creates good habitat for mosquitoes.  Milfoil starts growing earlier in the season than most native aquatic plants and therefore shades the majority of them out.  This has negative impacts on fish and wildlife habitat.  This aquatic invader can also invade fish spawning habitat, clog irrigation intake pipes, and can hinder power generators.  It has the ability to reproduce through broken off plant parts at a very rapid rate and can take over an entire lake in 2 years.  Once milfoil is established it is difficult if not impossible to eradicate.  

Identification  Milfoil species are easy to identify as a group because they all have feather-like leaves arranged in whorls around the stem.  Identifying individual species is not quite as simple.  It is so difficult that for many years Eurasian water milfoil and northern milfoil were classified as the same species.  There are a few characteristics that help in separating the noxious from the natives but they cannot always be relied upon.  Eurasian milfoil typically has twelve or more pairs of leaflets on each leaf, the leaves tend to collapse around the stem when removed from the water, and the mature leaves are typically arranged in whorls of four around the stem.

What can you do?  Preventing the spread of this weed is the most important thing we can do at this point.  Pick every fragment off of your boat or trailer and put them in a garbage can.  If you see plant fragments on someone else’s boat or trailer tell them about the threat that milfoil possesses.  Spreading the word is so important because an entire lake can be infested by just one tiny fragment.  Once a lake or river becomes infested there is no way to completely eradicate the invader.  Herbicide treatments, diver harvesting or hand pulling (containing all fragments), underwater rototilling, and instillation of bottom barriers are all somewhat successful in controlling the growth of milfoil.  If you are interested in helping stop the spread of Eurasian water milfoil learn how to identify and safely remove it, get other people involved in the prevention, and report any aquatic vegetation that you suspect could be the noxious species.  If you have any questions about Eurasian watermilfoil or any other plant call your local county weed district.

Visit the MWCA Weed ID pages for additional information and pictures of Eurasian Water Milfoil.

This series of articles was developed by Ravalli County.  If you would like to use these articles please contact Ravalli County Weed District Weed Coordinator at (406) 777-5842.

Download a copy of the the complete press release with links to webpages, details on species of concern and more.

Eurasian watermilfoil is a priority 1B noxious weed in Montana and currently found in the Noxon and Cabinet Gorge reservoirs.

Download a copy of the Dept of Agriculture letter proposing EWM management area and details on the public hearing June 3.

Visit our weed ID page and library for more information on Eurasian watermilfoil.

Eurasian watermilfoil is a submersed aquatic plant that forms dense tangled beds that can competitively displace submersed native plant communities, reduce recreational qualities of water bodies, reduce water flow, clog industrial, agricultural, and drinking water supplies, and negatively impact fish and wildlife. If was first reported in Montana in Noxon Reservoir (Sanders County) in 2007. Plants primarily spread through stem fragmentation. Water recreation (primarily boats and boat trailers) is the predominant vector of long distance spread. After prevention, early detection and immediate action to contain and eradicate infestations are the most important management actions for Eurasian watermilfoil in Montana.

Download the booklet from MSU Extension now.