Jun 27, 2017 6:22 PM

The East Hampton Town Trustees are working with Suffolk County Vector Control officials on a plan to reduce the amount of aerial spraying of pesticides targeting mosquitoes in wetlands.

Tom Iwanejko, the director of Vector Control, said on Tuesday that his goal is to use the least amount of pesticide, while also trying to restore the wetlands in a way that targets stagnant waters where mosquito larvae thrive.

Accabonac Harbor is the initial focus of the effort. On Monday night, the East Hampton Town Trustees approved a resolution to participate in a program put together by Suffolk County Vector Control, where spraying will target only areas of Accabonac Harbor that have high concentrations of mosquito larvae.

Francis Bock, the clerk for the Town Trustees, said he believes the program will start within the next two weeks, though both sides still have to iron out details, like who is going to do the testing to identify the targeted areas.

According to Suffolk County Legislator Bridget Fleming, with the help of Stony Brook University and The Nature Conservancy, Vector Control will adjust spraying based on larvae counts this season. Vector Control crews will test the marshes and then use GPS to mark the spots where clusters of mosquito larvae are found. Instead of widely spraying the insecticide methoprene, it will be used in smaller quantities to target those spots.

Mr. Bock said on Tuesday that the testing by Vector Control will be more frequent and the targeting used more extensively.

All of this stems from a decision by the Town Trustees and Vector Control in December 2015 to declare an area of East Hampton’s waterfront completely off-limits to spraying, and began looking at possible locations for a no-spraying three-year test run.

The East Hampton Town Trustees have objected for years to the use of methoprene, a chemical that stunts the development of larval mosquitoes, preventing them from breeding. It is the main weapon in Vector Control’s effort to keep mosquito populations in check, but environmentalists, local officials and fishermen have blamed it for die-offs and maladies among various local marine species like crabs, lobsters and shrimp that are not-too-distant cousins, genetically, to mosquitoes.

The county has faced a battery of attacks from environmental groups for its use of methoprene on salt marshes around local bays. Kevin McAllister, the former Peconic Baykeeper and director of Defend H20, has filed two lawsuits and repeatedly challenged Vector Control’s management plans, accusing the agency and the County Legislature of ignoring state environmental regulations in their fervor to control mosquito populations amid public health concerns over West Nile virus.

Connecticut, earlier this year, adopted a ban on the use of methoprene in coastal areas or any Long Island Sound watershed unless there is a confirmed fatal case of West Nile virus in a large population center.

Both the Southampton and East Hampton Town Trustees began asking the county to halt spraying over their respectively owned marshlands more than a decade ago, and each board has sent letters reiterating its objections annually. But the spraying continued.

By focusing on high concentrations of larvae and targeting specific areas, Mr. Bock said he is hopeful that East Hampton Town will see an overall reduction in the use of aerial pesticides.

“I think it’s a step in the right direction,” he said. “We’ve been talking for a while, trying to figure something out, just to alter what’s going on now. Anytime we can work together with a program, that’s certainly a step in the right direction.”

Mr. Iwanejko said his ultimate goal is to use the least amount of pesticide as possible. When spraying in saltwater environments, the only two products that Vector Control uses are methoprene and BDIs, which is bacillus thuringiensis subspecies israelensis solids. The two, he said, are used because they have less impact on the environment.

Mr. McAllister said he does not buy Vector Control’s approach. He acknowledged that BTIs are fairly benign and safer than methoprene—but he dismisses talk of the safe use of methoprene to control mosquitoes in wetland areas.

“It’s a lot of scientific debate,” he said. “You just can’t put it in a box, put a wrapper on it and say it’s the end all.”

He added, “Stop spraying methoprene—it’s a poison.”

Mr. Iwanejko said Vector Control has a second approach it wants to try, in an effort to control the mosquito population while limiting the use of pesticides.

He said the plan is to undertake wetlands restoration projects, focusing on the hydrology of areas where the bottoms of waterbodies have been changed by dredging. In some cases, that creates stagnant areas where there is little water flow in creeks and other coastal areas—the perfect environment for mosquito larvae to thrive.

Mr. Iwanejko said Vector Control wants to try to change the topography of the creek bottoms and other underwater areas to create more tidal flow farther inland, to keep those areas flushed regularly to discourage the growth of larvae.

Ms. Fleming, who represents the East End in the County Legislature, said she has made it a point to work toward the elimination of methoprene spraying. “I can say the County Vector Plan … includes the reduction or elimination of methoprene for health concerns,” she said.

Suffolk County has always been reticent to address the issue, but she said the difference this time is that county officials are working to avoid the use of chemicals when possible. She explained that even if everyone does not agree on scientific data, everyone seems to agree on a goal of reducing or eliminating the use of chemicals.

“I hope, and I believe from my discussions with the director of Vector Control, this could serve as a protocol which could be replicated in other communities,” she said.

Staff writer Michael Wright contributed to this story.