The town of Chilmark will go to the state’s highest court to block a group of riparian owners on Squibnocket Pond from using herbicides to control phragmites.

Acting on the advice of town counsel Ronald H. Rappaport, the Chilmark selectmen voted Tuesday night to appeal a Massachusetts Land Court ruling that upholds a plan by the homeowners to use Rodeo to control the invasive plants in the pond.

Mr. Rappaport recommended that the town petition the Supreme Judicial Court to take the case rather than going through the state appeals court.

“I'd just as soon get to the supreme court and see if they’re willing to take it,” he said.

Six riparian owners calling themselves the Squibnocket Pond Organization have been at odds with the town over the issue. A year ago their plan to apply Rodeo to 20 phragmite colonies on the pond was approved by the Chilmark conservation commission and the state Division of Fisheries and Wildlife. But later the building inspector refused to issue a permit for the project, citing a town bylaw that prohibits the use of herbicides around the pond. Last spring the zoning board of appeals upheld the building inspector. The landowners appealed the decision in state land court.

The summary judgment ruling for the landowners was issued Jan. 8 by the Hon. Gordon H. Piper. In his decision, Judge Piper said the bylaw is “invalid and unenforceable” because it “prohibits, controls, limits and regulates” the use of glyphosate-based herbicides such as Rodeo, which are controlled and regulated exclusively under the Massachusetts Pesticide Control Act.

Reached by telephone, Charlie Parker, a member of the Squibnocket Pond Organization, had no comment on the town’s decision to appeal but said the land court ruling speaks for itself.

“I thought the judge’s decision was extremely clear and unequivocal and unambiguous, I was extremely impressed with the level of preparation,” he said.

Speaking to the selectmen Tuesday night, Mr. Rappaport said the dispute goes broadly to the heart of two key issues: herbicide use on the Vineyard, which has been the subject of much public discussion in recent months over NStar’s plan to resume spraying to control vegetation around power lines, and also the legal issue of a town’s ability to create regulations to control pesticides.

Given the state case law in the matter, the town attorney said the land court ruling favoring the landowners was not unexpected.

The decision referenced a 1985 state SJC decision involving the town of Wendell, which found that the state pesticide law superseded local law.

Mr. Rappaport also sketched other case law dealing with pesticide use. He spoke of a 1991 U.S. Supreme Court case involving a Wisconsin farmer who wanted to spray aerial pesticide. In that case a local rule prohibited the spraying but federal law did not. The U.S. high court found that the federal pesticide law did not preempt local regulations dealing with the use of pesticides. Local governments are often best suited to create their own environmental regulations, the court said, and it gave states the right to give municipalities power to regulate pesticides.

Control of phragmites, an invasive species, has been a subject for widespread study and discussion on the Vineyard. Also known as the common reed, phragmites form dense colonies over native pondshore habitat. Because the reeds reproduce via both rhizomes in the soil and by seeding, management can be challenging. All rhizomes must be eliminated in order to fully eradicate the tall strands.

Phragmites elimination projects have been undertaken in several areas on the Island, including Crystal Lake in Oak Bluffs, Black Point Pond in Chilmark, Chilmark Pond and Edgartown Great Pond. Rodeo, which contains the active ingredient glyphosate, was used in all cases. Glyphosate acts on the plant enzymes to inhibit growth. Other eradication methods include grazing animals, laying black plastic, increasing water salinity and dredging.

But Squibnocket Pond is unique, Mr. Rappaport told the selectmen this week, and considered the most fragile Great Pond on the Vineyard because it does not breach to the sea.

He referenced a 62-page study that was done by the Marine Policy Center in Woods Hole and led to the adoption of the Squibnocket Pond special overlay planning district in 1990. Among other things, the bylaw prohibits the use of chemical fertilizers, pesticides and herbicides within 500 feet of the pond.

“[The report] found that Squibnocket Pond was significantly threatened and that the town should take significant proactive steps to enact zoning to protect the pond, and the attorney general upheld it,” Mr. Rappaport said.

“What’s put in the pond stays in the pond,” he said, summing up the conclusion of the report.

He also said: “Most of our bylaws don’t come out of lengthy studies.”

The report, authored by Arthur Gaines and James Braudus, examined the salinity of the pond, shellfish and alewife habitat and the watershed. It included management recommendations and said nitrogen loading was a concern.

“Our study illustrates the need for and value of a comprehensive and integrated approach in managing coastal resources at Squibnocket,” the report said. “Because of the importance of salinity and flushing in terms of habitat, the extent of exchange with the sea is of primary importance to living coastal resources of the pond and the larger sphere of biota and human activities depend on them.”

The report noted that at one time the pond had been artificially opened to the sea. A map from 1776 in the report showed a slight opening at the southeastern corner of the pond and two small artificial connections to the sea, one of them the herring creek which is still open.

The report also took special note of: “[The pond’s] limited watershed and abundant wetlands; existing laws and self-imposed restrictions surrounding development; and an uncommon sensitivity and commitment of private landowners here to environmental protection.”

An unnamed private donor has agreed to pay for part of the town’s appeal in the court case. Town executive secretary Timothy Carroll said the donation will come from the Jewish Communal Fund of New York.

On Tuesday Mr. Rappaport further suggested that the town put a home rule petition question on the annual spring ballot asking the state legislature to allow the town to regulate pesticides around the pond.

He said with so much public attention focused on the NStar herbicide spraying issue, other towns may want to join the cause with their own petitions.

“Other towns may want to join so the role of municipalities is protected and preserved,” Mr. Rappaport said.

“I think it’s going to be a huge case,” selectman Bill Rossi said.