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Big Drop in Larvicide Use

Thu, 10/31/2019 - 13:21

A pilot program launched in 2017 to narrowly target the application of mosquito larvicide around Accabonac Harbor brought another dramatic decrease in its use this year, East Hampton Town and Suffolk County officials announced on Friday.

A group of those officials, along with members of the Accabonac Protection Committee, the Nature Conservancy, and the Group for the East End, crowded onto the deck of Edwina von Gal’s Springs residence on Friday to discuss the results of this year’s program, in which volunteer citizen scientists sampled waters in the marsh at locations that were mapped by geographic information system, or GIS, software via a smartphone app. The data were forwarded to the vector control division of the county’s Public Works Department, where officials used it to make decisions as to where and when to treat an area. 

When the program was fully implemented in 2018, volunteers entered almost 6,000 sample locations between June and August, which vector control officials used in applying larvicide in 7 of the 11 weeks studied. The program also identified “hot spots” of mosquito breeding, resulting in the treatment of less than half the area over which larvicide was previously applied and a cost saving to the county of $18,000.

Results announced on Friday showed a continued reduction in the use of larvicide, the areas over which it was applied, and the cost. Of this year’s 13-week sampling season, county officials deemed larvicide application necessary in only four weeks. The total area treated between 2016, before the program was implemented, and this year represented an 81-percent decrease. Costs have been reduced by 77 percent.

Legislator Bridget Fleming credited Tom Iwanejko, the director of vector control. “Tom’s having taken over from a prior administration opened the doors to conversation where they had not been opened in the past,” she said on Friday. “Tom immediately recognized the value of the budget impacts, but also the value of maintaining the environment and restoring the ecosystem.”

Last year, the county began shifting its aerial larvicide application from a mix of methoprene liquid and Bti, a biological agent that is believed to be harmless to nontarget species, to a Bti and methoprene granule product, which reduces the effects of drift compared to the liquid.

Methoprene is controversial. Mr. Iwanejko’s predecessor insisted that it is harmless to nontarget species; others suspect its use contributed to a die-off of lobsters in Long Island Sound and is harmful to other nontarget species as well.

“What I had observed was that for many years no change was happening to this circumstance, where these very intense toxins are being sprayed on this gorgeous landscape, because of this intense disagreement,” Ms. Fleming said. “Each side was in its silo. I mention all this,” she said, “because it’s so important in our current divisive political atmosphere.”

“The results have been amazing,” Mr. Iwanejko said of the program. “It’s been positive all around.”

Supervisor Peter Van Scoyoc called the program “a shining example of what happens when you partner together private citizens, environmental organizations, and government at several different levels coming together. . . . Instead of just taking a broad brush of methoprene and spraying it all over any area that may contain a mosquito, through the efforts of volunteers we’re able to pinpoint specifically where breeding mosquitoes are and therefore limit the use of pesticides.”

Susan McGraw Keber, a town trustee who helped organize and participated in the sampling program, said that she identified two breeding hot spots last year. “This year, natural growth has occurred, and there were fewer mosquito larvae to sample,” she said.

The program will expand into a marsh restoration effort, officials said, starting with a Dec. 5 meeting with town and vector control officials.

“We’re looking forward to the next phase of this,” said John Aldred, a trustee. “Hopefully, we can get this started next season, to take the information we’ve gathered and start to look at these hot spots and see what steps we can take to minimize the conditions that are causing the breeding.”

“This was a way we could control mosquitoes and also we could restore the wetlands,” Mr. Iwanejko said. “It’s called integrated marsh management.”

Those present noted an increase in red-winged blackbirds in the area, as well as dragonflies and spartina, a saltmarsh grass. Two bald eagles are now nesting near Ms. von Gal’s residence.

Ms. McGraw Keber said she was hopeful that “we can also . . . educate our neighbors who live on the harbor about the pesticide use that they would apply personally, and let them understand that that adds to the contamination of our beautiful harbor.”

Ms. von Gal’s Perfect Earth Project is a nonprofit organization that works to raise awareness of the dangers of lawn and garden chemicals and educate property owners and landscape professionals about natural techniques.

“I am so proud of my community for what you have done,” she said, “all the different people working together on this. It’s a remarkable model. I hope this idea and this kind of working together can spread.”


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