Purple Loosestrife | Swimmer's Itch
Loosestrife eating beetles introduced into Lake Mitchell
| Loosestrife becomes dominant plant in Big
Cove Purple loosestrife is an invasive plant native to Europe and Asia which infests wetlands, wet meadows, shorelines, and roadsides. Each 4 to 7 foot plant produces 30 or more beautiful purple spikes that bloom in late summer and can produce over 2.5 million seeds. Big Cove is ringed by thousands of purple loosestrife plants whose beautiful, but unwanted magenta flowers, create a real threat to the health and survival of that wetland shoreline. Wetlands are the most biologically diverse productive component of our ecosystem. Numerous species of plants, birds, mammals, reptiles, insects, fish, and amphibians rely on healthy wetland habitat for their survival. Once established, purple loosestrife frequently becomes the dominant vegetation by out-competing native plants. As native communities are reduced, so, too, are wildlife species that depend on them. Declines in ducks, geese, and other wetland birds as well as muskrats, mink, and some amphibians have all been noted. There is also some concern that purple loosestrife may reduce spawning habitat for some fish. |
Purple Loostrife |
Methods of Controlling Loosestrife
If dealing with a few isolated plants, cover the flowering
spikes with a plastic bag, and dig the plants up, being careful to get all the
root system. All plant material should be dried and burned, or placed in a
closed black plastic bag in the sun for several days where high heat will kill
the plant and seeds.
Where permitted, plants may be treated with an approved
herbicide. RODEO is an effective herbicide. However, it is non-selective and
will kill most vegetation it contacts. Spot sprays directed at the early
flowering stage are most effective. Broadcast sprays are not recommended.
| Loosestrife-eating beetles introduced into
Big Cove in 2006 A natural enemy of purple loosestrife is the galerucella beetle, which feeds on bud, leaf, and stem tissue. The Michigan Department of Natural Resources has successfully used these beetles for control since 1994. Once introduced, it takes 3 to 15 years for the beetles to get purple loosestrife under control. Galeruclla beetles eat only purple loosestrife and pose no threat to humans or pets. Several dozen of these loosestrife eating beetles were collected by Dave and Cyndy Foley near Petoskey in June and placed on Big Cove plants. By summer’s end some plants had been destroyed but this project will require an ongoing program of introduction of Galerucella beetles. The beetle collection was coordinated by the Tip of the Mitt Watershed Council. In June a group from the Lake Mitchell Association will again collect and release beetles. |
Cyndy Foley places beetles on Big Cove
plants. |
To learn more about purple loosestrife go to:
www.miseagrant.org.
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What about swimmer’s itch?
Several years ago the Wexford County Department of Public Works (DPW) commissioned a study with Hope College to determine the exact source of our swimmer’s itch. That study showed that waterfowl were to blame, mostly the ducks and geese that stay all summer. For many years the DPW applied tons of copper sulfate, which is biologically dangerous, to combat swimmer’s itch on Lake Mitchell. Now, as a result of the study, the County DPW instead inoculates the waterfowl through feeding, and copper sulfate is no longer needed. We can all do our part by not feeding the waterfowl. Artificial feeding of waterfowl leads to unnaturally high numbers of waterfowl on our lake, which makes the swimmer’s itch problem worse.
Although there are still cases of the itch reported every year, the incidence is much lower than it used to be. The parasite that causes swimmer’s itch uses ducks and snails as hosts before infesting humans. Children, often are most affected, because their skin may be more sensitive, and they spend time playing in shallow water where the swimmer’s itch parasites are more concentrated.
Infected swimmers may notice red spots within a half-hour of leaving the water. These spots may enlarge for the next 24-30 hours and may itch for a week. Toweling off may help. Others find protection by applying baby oil before swimming or taking a shower after leaving the water.
History shows that the incidence of swimmer’s itch may range from few cases a season to widespread problems. Variables affecting swimmer’s itch include:
What can be done to prevent or reduce swimmer’s itch?
Do not feed the ducks.
To find out more about swimmer’s itch go to: www.hope.edu/swimmersitch
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