Lake Benton pondweed control planned this spring

LAKE BENTON — Treatment for curly-leaf pondweed at selected locations in at Lake Benton will take place within the next several weeks.

Lincoln County Environmental Officer Robert Olsen said vegetative management plan documentation and lake treatment permitting are being finalized to allow for April and May herbicide applications. They will be targeted to the area near the Lake Benton city limits south and southeast of Norwegian Creek County Park, as well as the west shore near Stony Point between Lake Benton and Tyler.

“It will cover about 200 acres that have had high pondweed populations,” Olsen said. “Some of the treatment will wait until mid-May. The weeds need to be up for it to be effective.”

He said herbicide applications will be timed around both the May fishing opener and Minnesota Department of Natural Resources stocking projects. Small newly-stocked fish might be affected if they’re immediately exposed to treatment chemicals. Once they’re introduced to the lake, they’ll have the ability to swim away from areas being treated.

Property owners along the lake were given an opportunity to opt out of the treatment process if they did not want chemical applications near their shorelines. Olsen didn’t receive any requests to be left out of the project.

“We didn’t receive any letters, which indicates that everyone wants the weed control,” he said. “Pondweed has been a concern in the past for fishing and recreation. We’ve seen the need to plan effective treatments at the right times.”

Curly-leaf pondweed became an issue at Lake Benton in the early 1990s, when it rapidly expanded from its origin near the eastern shore and boat launch to affect almost a third of the lake.

Curly leaf is a shallow counterpart to Eurasian Water Milfoil, an invasive weed issue in deeper lakes of central and northern Minnesota. Pondweed has a much smaller impact on lakes with enough depth, but spread rapidly in shallow prairie lakes where they get enough exposure to sunlight.

After limited success with weed harvesting and targeted chemical treatments, a whole lake treatment was carried out in 2008 with approval from the DNR. Afterward, it took much longer for pondweed to reappear.

Lake Benton Mayor Bob Worth said lake area residents hope that treatment plans in 2019 lead to a similar result, one that provides long term weed control benefits.

“Our first choice was another whole lake treatment because it was very effective last time,” Worth said. “Having some weed treatment is much better than nothing. It needs to be treated before the weeds get out of control.”

Lake Benton has served as the site of fishing events that typically attract about several hundred participants. Both Norwegian Creek and Stony Point parks also bring in substantial amounts of campers throughout the summer season.

Regional DNR aquatic invasive species specialist Allison Gamble said the 2019 control planning process is intended to keep Lake Benton’s pondweed population at a well-managed level that promotes favorable habitat and good recreational opportunities.

“We’ve chosen treatment sites that have both high weed populations and important roles for lake residents and visitors,” Gamble said. “We’re expecting that what’s done this spring will have a favorable impact.”


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