Guilford targets invasive lake plants

In an effort to combat invasive plants, Guilford will apply the chemical glyphosate and two other herbicides to Lake Quonnipaug later this month.

The state Department of Energy & Environmental Protection issued an aquatic pesticide permit for Lake Quonnipaug last month, approving the use of glyphosate as part of an herbicide treatment, according to DEEP spokesman Will Healey.

The herbicide treatment, which also includes diquat dibromide and flumioxazin, is meant to beat back invasive plants that hinder recreation and threaten native species in Lake Quonnipaug, Guilford First Selectman Matthew Hoey said.

Hoey has received a couple of calls from residents worried about use of the herbicide, he said.

“My explanation is that it is an approved material by both the EPA and DEEP after exhaustive studies,” Hoey said. “They are the regulatory body that we rely on and comply with to make treatments like this for the lake.”

Healey said both the fisheries and wildlife divisions were involved in reviewing the permit application, and, “We have no reason to believe that the permitted treatment will result in adverse impacts to human health or the environment.”

Further, the federal Environmental Protection Agency has found that glyphosate is “not likely to be carcinogenic to humans,” an EPA spokesperson said.

Glyphosate has been used in Lake Quonnipaug for the last several years, said Kevin Magee, the town’s environmental planner.

The treatment, scheduled to begin Aug. 12, targets the nonnative species Eurasian watermilfoil, sand wart and curly-leaf pond weed, Magee said.

The town has had some success with similar treatments in the past, according to Magee.

“We’re starting to see some improvement with the removal of some invasives and having native plants come back in,” he said.

The herbicides also will be used to eliminate some water lilies that make it hard for boats to enter the lake, according to Magee.

To ensure safety, the town will notify residents in advance of the treatment and post warning signs at all of Lake Quonnipaug’s major access points, Magee said.

David Roach, general manager of All Habitat Services, the firm contracted to apply the treatment, said the average resident does not need to be concerned about exposure to glyphosate.

“Nobody’s going to be out on the lake when we’re doing this,” Roach said.

Since the firm will apply the glyphosate to the surface of the lilies, it will not have much contact with water or people, Roach said, adding that if it does get in the water, it will quickly become diluted.

But Roach said his employees are trained to use the herbicide safely and wear personal protective equipment.

“We really wouldn’t have them doing anything that we didn’t believe was safe,” he said.