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Group works to stop curly-leaf pondweed invasion

Curly-leaf pondweed was first discovered on 11th Crow Wing Lake in 2006 during a June fish survey conducted by the Department of Natural Resources. (Photo courtesy of

A task force to combat the spread of curly-leaf pondweed on the Crow Wing chain of lakes is moving forward, members of the 10th and 11th Crow Wing Lake Association defining a plan of action Saturday.

Curly-leaf pondweed has been identified in the upper basin of 11th Crow Wing Lake, its proliferation a concern to residents in the lower watershed.

"We have to declare war," lower basin 11th Crow Wing Lake resident Katie Magozzi said Saturday. "Doing nothing is a decision to fail. We have to control it in the easterly basin."

DNR aquatic invasive species specialist Darrin Hoverson said a full survey was conducted this past summer of native and non-native vegetation on the lake to develop baseline data.

The majority of the AIS was found on the north side of the east bay, he said, with some found near Pixie Point. None was found in the lower basin.

The lake's level of infestation is low, he said. But management will need to continue. "We have never had an incidence of eradication of invasive species in Minnesota," he told the lake residents.

"I don't think the average person realizes the destructive potential," 5th Crow Wing Lake resident and county commissioner Don Carlson said of AIS.

Lake resident Scott Solberg reported via e-mail to lake association president Kim Bowen that he found raking disturbs the bottom, which tends to promote growth and drifting turions (the plant's primary reproductive element). He recommended use of chemicals to combat the exotic.

Hoverson agreed disturbance of the lake bottom can spread the AIS.

But herbicides "are not selective," he said of the impact on native vegetation. He recommended administering "aquacides" before native plants are up and growing, in the early spring. Permit fees are waived for hand removal, but a $35 fee remains for chemical application, for monitoring purposes.

Introducing additional native plants to overcome AIS is not practical, he said of a suggestion. And some practices being used on other lake infestations are "doing more harm than good," Hoverson said of the impact on water quality and fisheries.

Coalition of Lake Associations president Dan Kittilson suggested hiring a professional, as Portage Lake has done.

"Bottom line is, we can't afford it," Bowen said.

And Hoverson did not recommend it, noting the lake's native vegetation tends to keep curly-leaf pondweed in check. "Chemicals have as many faults as virtues."

Lake resident (and a dad) John Seals questioned the long-term effects of aquacides on humans.

Hoverson explained they become inactive within a week.

"Doug (Kingsley of DNR Fisheries) recommends hand pulling as opposed to chemicals," Hoverson said, noting lily pads are "very susceptible to chemicals."

Hoverson recommends removing the plant before turions form. Eurasian milfoil breaks up and proliferates with hand pulling, he explained. This is not the case with curly-leaf pondweed.

But the life cycle of curly-leaf pondweed gives it a competitive edge. It begins a rapid growth period when ice melts and water temperatures warm. The growth is so rapid it can crowd native germinating plants.

Ed Becker, a resident of 8th Crow Wing, said his lake association "wants to make sure this a focused effort. We don't want a curly-leaf pondweed mafia."

"Our concern is not doing anything, causing irreparable harm to the lake," Seals told him of the "never-ending battle."

Hoverson said the permit process defines where chemicals may be applied. "You need to protect the native species. That's what holds curly-leaf pondweed at bay." He recommended using no chemicals with natives "unless it's very focused."

Portage Lake, where residents have battled the weed for several years is naturally eutrophic, Hoverson said. "Eleventh is very clear, very clean. Most lakes that experience the problem have a water quality problem. Eleventh doesn't have a water quality problem."

Hoverson cited Menahga's proactive approach on Spirit Lake, rerouting storm water, for example.

"The city of Akeley should be at the table," Magozzi said. "Shame on them."

And Kittilson expressed concern with lack of representation from lakes in the lower chain. "I don't see the players at the table. You need partnerships with townships, the city." He cited Potato Lake, residents raising $65,000 as a "war chest.

"I don't see that happening here."

"This does not just affect 11th Crow Wing," Becker said.

Hoverson indicated money is available if a task force is formed. "With local partnerships, it's phenomenal what you'd be able to accomplish."