|Eurasian Watermilfoil (Myriophyllum
spicatum) is an invasive, submersed aquatic plant that was
first introduced to North America from Europe. Spreading primarily
by overland boat transport to over 45 U.S. states, it began occurring
in midwestern lakes between the 1950s and 1980s. In 1987, the first
discovery of Eurasian Watermilfoil in Minnesota was found in Lake
Minnetonka. Since then, it has spread to over 112 water bodies
can it be a problem?
can form thick underwater stands of tangled stems and vast mats
of vegetation at the water's surface, especially in nutrient-rich
with recreational water activities such as boating, fishing, and
- Crowds out
important native aquatic plants which decreases important habitat
and diversity in the lake
(compiled and presented by Larry Space and Joanna Wright on the
Impact of Small Lakes of Vermont by the Invasion of Eurasian Watermilfoil:
A Property Owners Perspective)
Eurasian Watermilfoil may…
boat repair and maintenance costs (One boat owner in Vermont
spent $800 repairing his boat when the motor intake became clogged
a decline in native plant diversity (Madsen, et, al. 1991;
Depress real estate values (Bates et. al 1985)
Inhibit water circulation (Smart and Doyle 1995)
Reduce the levels of dissolved oxygen, cause the release
or build up of nutrients…which may provide unfavorable conditions
for both macroinvertebrates and fish (Lille & Budd 1992)
Reduce the number of invertebrates (fish food) per square
meter by ½ as compared to native plants (Keast 1984)
Have three to four times less fish versus native plant
beds (Keast 1984)
Cause significant increases in permanent pool mosquitoes
(Bates et. al 1985)
see what species make up the aquatic plant community in Lake Independence
and other MCWD metro lakes click here.
does it spread?
leaf fragments spread by watercraft to new lakes or rivers or
areas in the same water body can take root and grow into new plants
Underground runners also generate new plants in the same
Watermilfoil may become entangled in boat propellers, and may
wrap around other external parts of your boat. Stems can also
become lodged among any watercraft apparatus or sports
equipment that moves through the water, including boat trailers.
actions YOU take as a responsible boater are critical in preventing
the spread of Eurasian Watermilfoil to new Minnesota water bodies.
Clean your boat.
remember to remove all aquatic plants from your boat, motor,
and trailer before you enter and after you leave any lake or river.
it in my lake?
out from the Minnesota Department of Natural Resources EXOTICS
IN MINNESOTA WATERS
Be on the
- Eurasian Watermilfoil
may be present in your lake or river, but has not yet been discovered.
- Learning to
recognize Eurasian Watermilfoil and reporting new sightings
are critical in stopping the spread of this invasive plant. (Link
to Report New Sightings on Exotic page)
- Think you might
have found a new infestation of Eurasian Watermilfoil? Contact
the MN Department of Natural Resources at (651) 296-2835 or (888)
646-6367 or Mail them a sample of a suspected milfoil plant
in a sealed, plastic bag
Eurasian Watermilfoil Program
Ecological Services Section, Box 25
500 Lafayette Rd.
St. Paul, MN 55155-4025
does it look like?
- Submersed aquatic
- Long stems
with soft, feathery leaves
- Leaves usually
attached in whorls of four
- Each leaf has
12-20 pairs of leaflets
- Leaves limp
out of water
is only one of six aquatic plants in the Watermilfoil family found
mistaken for native Northern Watermilfoil
out of water
Eurasian Watermilfoil be eradicated from my lake?
Watermilfoil is established in a lake, it is almost impossible to
eradicate. It does not cause problems in every water body it infests,
but for those that it does, three of the most common control measures
for managing nuisance growths are listed below.
Eurasian Watermilfoil in your lake?
Biological Control Research
Eurasian Watermilfoil in Lake Minnetonka
The Lake Minnetonka
Conservation District and Hennepin Parks currently control nuisance
growth of Eurasian Watermilfoil in Lake Minnetonka in cooperation
with Department of Natural Resources and lake homeowner associations.
They primarily use mechanical
harvesting to control nuisance Eurasian Watermilfoil, but
also use chemical treatments in small areas around boat launches
and fishing piers where the harvester can't operate.
grows mostly around the shoreline, especially in channels
and shallow areas with high boater traffic and in areas where past
harvesting has occurred. Problem areas vary from year to year so
the Lake Minnetonka Conservation District flies over the lake to
determine which areas need to be harvested.
the costs of Eurasian Watermilfoil Control?
The Department of Natural Resources spent approximately $119,000
for maintenance management of Eurasian Watermilfoil in 1999!
Minnetonka Conservation District 1999 Eurasian Watermilfoil Final
Department of Natural Resources Exotic Species Annual Report
Managing Eurasian Watermilfoil in Minnesota
share the status of Eurasian Watermilfoil in your lake.