Aquatic Herbicides Ring up More Success Stories

Published October 1, 2005

Advances in chemical technology are increasingly allowing weed-choked lakes around the country to be transformed into vibrant recreation and wildlife refuges. Although environmental activists consistently oppose the use of new aquatic herbicides such as Sonar and triclopyr, the summer of 2005 provided an impressive record of success in eliminating destructive invasive weeds, such as Eurasian milfoil, while leaving native plants and fish unharmed.

As word of this success has spread, more lake communities are demanding aquatic herbicide treatment.

Lakes Transformed

The July 11 Rutland Herald reported that after treating Vermont’s Lake St. Catherine with Sonar last year, the lake is mostly free of invasive milfoil for the first time in 22 years. In recent years, invasive milfoil had befouled up to 65 percent of the lake, making boating, fishing, and swimming nearly impossible.

Similarly, residents near Houghton Lake, Michigan report application of advanced aquatic herbicides has transformed their lake.

“By the late 1990s, Houghton Lake was very weedy,” said Dick Pastula, secretary of the Houghton Lake Improvement Board. “The entire lake was choked with milfoil. We had even lost a quarter of the lake surface to milfoil. It was so bad that people were playing pranks, putting up ‘For Sale’ signs on large, floating weed islands. You couldn’t swim, you couldn’t fish, you couldn’t take out a boat, you couldn’t do anything. The lake was an absolute disaster.

“We began treating the lake with aquatic herbicides in May 2002,” said Pastula. “Results have been unbelievably good. By August 2002 the lake was entirely free of weeds. We had no fish kill. We had no algae bloom. We have had very minimal, entirely manageable re-growth of weeds since.”

Lake Houghton residents have been thrilled with the results, according to Pastula.

“I could have run for sainthood after that, the community was so happy,” Pastula noted.

Even people who had worried about introducing herbicides into the environment are now supportive. “We had some people raise environmental concerns before treatment, and many more that were sitting on the fence,” Pastula reported. “Now, with the exception of only a very few people, the entire community considers treatment a total and tremendous success. People see that this has been a win-win solution.”

Minnesota Goals Exceeded

In Minnesota, citizens near Lake Benton “feel [the] first year’s goals [for weed reduction] have not only been met but exceeded,” according to the July 13 Pioneer County Star.

“A measure of the improvement is the much greater lake usage,” reported the Star. “The lake was busy on the July 4 weekend with fishing, boating, water skiing, and swimming. There were line ups to boat ramps, which hasn’t occurred for years, observers said.”

“I had thought it would help,” Lake Improvement District Board member Mark McCallum told the Star, “but was a little skeptical. The results far outreached any expectation I had. I’m nothing less than jubilant.”

Residents Return

“A year ago, Capitol Lake was choked with Eurasian water milfoil,” reported the July 27 Olympia, Washington Olympian. “Today, only a few spot infestations of the nuisance weed remain, leading lake managers to label the controversial decision to treat the lake with an herbicide last July a success.”

“Right now, it looks like the herbicide is working–the lake looks beautiful,” area resident Marcus Wooten told the Olympian. “It’s got me coming back down to the lake again.”

The lake was treated with triclopyr after studies indicated the herbicide would kill invasive milfoil but not affect human health or area wildlife. “There have been no reports of environmental damage or public health problems associated with the herbicide spray,” reported the Olympian. “Native freshwater plants survived the chemical spray, as expected.”

James M. Taylor ([email protected]) is managing editor of Environment & Climate News.