Flowering rush treatment shows promise
<p>Flowering rush infestations can overtake bays and render them unusable by boaters and swimmers. (Photo courtesy IDAHO LAKES COMMISSION)</p>
SANDPOINT — An effective way to nip flowering rush in the bud may have been discovered.
Bonner County Weed Supervisor Brad Bluemer said he is finding success with killing the noxious weed using off-season, dry-ground herbicide applications.
“It was kind of a shot in the dark that happened to work,” said Bluemer.
Bluemer began applying Imazapyr, a non-selective herbicide used kill broadleaf weeds, on 13 acres of an infestation that’s on private property.
Imazapyr had been applied on test plots of flowering rush, although it was unsuccessful. Bluemer suspects the treatments were unsuccessful because of the time of the year the herbicide was applied.
“The product is highly sensitive to sunlight,” said Bluemer.
Bluemer’s applications, which began last year, showed great promise in knocking back the weed.
If the treatment is proven successful, it would be a ray of light in a gloomy scenario. So far, a successful treatment method for the weed has been elusive.
“He’s probably coming the closest to having an effective treatment on this,” Erin Mader, program coordinator for the Idaho Lakes Commission, said at a recent State of the Lake presentation hosted by the Idaho Department of Fish & Game.
It was first detected in Lake Pend Oreille about eight years ago.
“Now we have over 400 acres of it,” Mader said.
Volunteers have been pulling flowering rush by hand to keep it out of high-use areas.
“It fills in bays,” she said. “It is impenetrable.”
It also breeds swimmer’s itch, a bacteria carried on snails which favor flowering rush, Mader said. As a result, an area can be rendered unusable even before an infestation takes over.
Another bright spot in Bluemer’s research is the cost. The herbicide costs about $40 per acre.
“It’s 75-percent cheaper than anything we’ve ever done in aquatic weeds,” Bluemer said.
Bluemer said Dr. Kurt Getsinger, a research biologist with the U.S. Army Engineer Research & Development Center, will be coming to Bonner County this year to evaluate the treatment area and provide input.
Bluemer, meanwhile, is excited to see how this year’s treatments turn out.
“We need to find something for rush or this lake’s going to be overtaken just like Flathead Lake,” said Bluemer. “I hope for landowners and the people of this area that we find an answer.”