Milfoil in the Northwest
In Northern Idaho weed infestations of lakes, rivers, and streams have been increasing over the last few years. Doug Freeland is the Northern Idaho expert on a particular type of underwater weed, milfoil, that is rapidly spreading through many freshwater sources in Idaho as well as the rest of North America. Freeland s expertise has been used by Idaho counties, Washington counties, and the US Forest Service on the particularly nasty weed.
Eurasian milfoil, or formally, Myriophyllum Spicatum L, comes from the Latin "mille" and "foille" meaning "thousand leaf." This is an accurate description of the weed; from a thin stem that rises from the bottom of lakes or rivers, many small, delicate green leaves about 2 to 5 inches in length emerge. The stem can continue to grow to the surface of the water and bloom a small flower above the surface for pollination. Eurasian milfoil spreads and grows quickly like dandelions in a lawn, but milfoil presents more of a problem than an eyesore. In some Washington lakes and streams, milfoil is a leading killer of native underwater plant life and native fish. Milfoil s chemical processes are poisonous to most fish that try to feed on the plant and other plants cannot compete with its rapid growth. Milfoil has caused even more problems though. Swimmers have become tapped and drowned in some thickly grown infestations in Western Washington. Obviously, milfoil has become an ecological and safety issue over the past few years. Doug Freeland has been heading the battle in Northern Idaho to control the weed.
Milfoil spread is due mostly to humans because boat bottoms, boat motors, fishing equipment, and other water craft catch the milfoil spores or pieces of milfoil and can easily spread the weed to a different body of water. There is a possibility of natural spreading of the weed; for example, spores could attach to the bottom of a duck that flies to another lake or stream spreading the milfoil. Spores are not visible to the eye as well, so many people may not be aware that milfoil spores are on their boat. The only way to prevent the human spreading of milfoil is to clean all areas exposed to milfoil spores before those areas come in with another body of water.
Since Milfoil has become such a widespread problem throughout the United States and Canada, many techniques have arisen to combat the spreading of the weed. Different methods have worked better in different climates to stop milfoil such as mechanical cutting, mechanical harvesting, weed rolling, aquatic herbicides, grass carp fish, bottom barriers, bottom screens, and of course manual harvesting. This technique is the main tool used by Freeland to clear lakes in Kootenai County and other North Idaho area lakes that are infested. While the task seems daunting when approaching 700 acre infestations of milfoil, Freeland s persistence has helped to control the spread of Eurasian milfoil. One of the more intriguing biological control possibilities is the milfoil weevil, or Euhrychiopsis lecontei. An employee from the Washington State Department of Ecology stated that these weevils occur naturally in many northwest lakes and love to eat European milfoil. Unfortunately, attempts to introduce the weevils into new lakes have not been successful and studies are being conducted in 1997 by the University of Washington to explore why. The weevil may hold promise as a biological control in the future, but appears to be impractical at this point. Another possible biological control is the moth of the water caterpillar Acentria Niveus. Reports state that the milfoil biomass in New York's Lake Cayuga was reduced by 90%, possibly because this non-native moth likes to nest in floating milfoil blossoms.
I chose this paticular article because milfoil affects my family and me. We own a cabin on Newman Lake that recently has become infested with milfoil. I ve swam, water-skied, fished, and dove in that lake ever since I was a little kid. I m naturally concerned to keep the water as clean as possible. I know many little children swim in the lake unsupervised, and the thought that they could drown in milfoil is very disturbing. Milfoil is capable of being controlled and helps recreation, plant life, and animal life throughout the Northwest and the rest of North America. I wouldn t want to see all the native plants and animals of Newman Lake be overrun by Eurasian milfoil.
1) Towle, Holt, Rinehart, and Winston Modern Biology "Glossary" 1998
2) Hudak, Luke "Milfoil Report" http://members.tripod.com/ hooters/index.html 1996
3) Milfoil Homepage http://www.wolfenet.com/ standing/milfoil/milfoil.html 1999
4) Drumheller, Susan "Trouble Lurks Below the Surface" Spokesman Review, Monday, November 27th, 2000