Fishers Island’s mosquito control program uses larvicide to control breeding mosquitoes. By definition, it attacks the larval stage, not the adult stage, when the mosquitoes have already hatched and are buzzing about and biting.

In the 1980s, the late John H. Thatcher Jr., president of FIConservancy, worked tirelessly to bring a non-toxic larvicide program to Fishers Island. Prior to that, Fishers Island used broad-area spraying to kill adult mosquitoes.

“I remember way back when the keeper of the Big Club (Fishers Island Club) golf course, would come boiling down Middle Farms in his Jeep, fogging the flats with spray,” said Ellie Kelly, former president of the FIConservancy. “Once, I was pushing my grandson in his stroller, and when the spraying started, I grabbed my grandson, raced for my car and closed the windows.

“This and other matters prompted the truly dedicated Cherry Rafferty to assemble meetings of concerned Island residents at her house. Meanwhile, John (Thatcher) researched an environmentally-safe way to control mosquitoes.

“Our group’s first effort was to send out postcards to everyone on Fishers Island about John’s plan, and that really stirred things up. Some people strongly supported the use of DDT, a sign of the times. But John persisted, and I do think that Fishers Island was one of the first places in the country to have established an environmentally-safe program to reduce mosquito populations.”

The larvicide was dispensed annually by summer larvicide teams, then commonly referred to as “Mosquito Girls”, who were interviewed and hired by Mr. Thatcher. The college students, licensed larvicide applicators, arrived from colleges and universities, including Princeton, Lehigh, UPenn, Colby College, Harvard and Columbia.

Suffolk County paid for the BTI larvicide, application tools and hourly wages for the young women. FIConservancy provided housing and a truck for on-Island transportation.

The young women worked their way from the East End to Race Point five days a week, donning waders and distributing larvicide, sinking into mud and fending off dive-bombing seagulls as they worked in ponds, ditches and marshes.

By 2016, Mr. Thatcher’s program had waned, as did other efforts to hire on-Island licensed applicators. Prior to that, seeing the writing on the wall, FIConservancy hired an outside contractor to follow the “Mosquito Girls”, taking pictures and documenting with GPS all of the sites they were treating and the amount of larvicide used at each site.

This precise information made for a smooth transition when Suffolk County Vector Control began sending its own licensed applicators to Fishers Island one day every other week during the summer.

FIConservancy still provides a truck for on-Island transportation and pays for Island resident Penn Sanger to motor the licensed applicators back and forth from Long Island to Fishers Island. The applicators rotate among the Island’s known breeding hotspots, donning backpacks of pellets, which “shoot” or propel the pellets into marshy areas, without the need for walking in with waders.

The Vector Control Division says that improvements to the larvicide mean that a single application will last weeks.