Daily Hampshire Gazette – Shutesbury petition: No toxic chemicals in the fight against invasive Japanese knotweed

SHUTESBURY — Invasive and destructive growth of Japanese knotweed along city streets and municipal rights-of-way is a growing concern for some residents, potentially reducing animal and insect biodiversity, degrading water quality and possibly preventing the growth of native trees.

While there is general agreement about the impact knotweed can have on the community, the possibility that chemical sprays, including the weed killer Roundup, could be used to control it is prompting a petition calling on the Select Board to impose a five-year moratorium on the use of glyphosate and similarly toxic herbicides for vegetation control on land under the city's jurisdiction.

The change.org petition, organized by former Conservation Commission Chair Miriam DeFant and MaryJo Johnson, has garnered more than 100 signatures so far, calling on the city to establish a committee to organize, train and implement an evidence-based knotweed management plan and study the impacts of that program.

It is also called for the creation of an exemption that would allow, if control methods other than glyphosate are ineffective over a three-year period, to use stem injection of chemicals to reduce glyphosate spread in the environment instead of spraying. However, this exemption should prohibit the use of glyphosate in wetlands or their buffer zones.

The petition is supported by the Shutesbury Rights of Wetlands Initiative, which describes itself as a grassroots organisation of environmentalists working to protect the town's fragile ecosystem.

A group called the Subduing Knotweed Coalition is pioneering efforts to control knotweed and is advising the Select Board and the Highway Department on developing methods to control this invasive species.

Mary Jo Maffei, who is part of the coalition, said it is a community initiative focused on awareness, education and solutions in New England.

“We are concerned about the spread and negative impacts of this invasive plant. Our focus is on early detection and removal. We are also working to stop mowing knotweed on our roadsides as this is the main cause of knotweed spread,” Maffei said.

The coalition has set up a website with warnings, including that knotweed should not be mown, that soil containing knotweed should not be moved and that care should be taken when composting. The coalition also has an emergency response team to dig up the invasive plants and an iNaturalist app where people can enter data on where they see knotweed that needs to be removed.

“Small populations can be completely eradicated and, accompanied by systematic monitoring, can completely prevent knotweed infestation,” the website states.

However, the coalition's website does not mention any possibility of chemical control.

Shutesbury has been working on the issue for many years. In 2013, a Japanese knotweed group submitted a management plan that proposed the use of pesticides at a cost of $2,000 for a two-day treatment. The treatment would have to be carried out over a three-year period at a total cost of $6,000. However, the plan was never implemented.

City Manager Becky Torres said the city has, however, taken some steps over the years to mitigate the impacts by using a method of removal, drying and then disposal. In informal discussions with the coalition, she said members were referred to the Conservation Commission for a response on possible actions and whether their suggestions would need to be implemented by filing a motion for a determination of applicability or a letter of intent.

Critics of the chemical use call it “shortsighted and unwise” because knotweed is only found in remote areas of the city and glyphosate poses a risk to wetlands in a city that relies on private well water. They point to previous concerns about contamination, including PFAS in some wells, a gasoline leak under the fire station and road salt.

In a letter to the health department, DeFant and Johnson wrote: “Given that knotweed infestations continue to occur sporadically in Shutesbury, we believe the town should refrain from using glyphosate until these other methods have been tried and found to be ineffective. A prudent policy of extremely conservative use of herbicides on town-owned properties benefits the town and its residents.”

In their letter to the Nature Conservation Commission, they call for “a comprehensive, holistic consideration of the risks of upstream runoff and viable alternatives to spraying the leaves” as well as “a cost-benefit analysis to achieve the best outcome.”

Scott Merzbach can be reached at [email protected].