CRANBERRY ISLES — Mosquitoes have been driving residents of the Cranberry Isles crazy for at least a century.
Voters will soon consider a renewed effort to control the pests, with the deployment of a naturally occurring bacterium called Bacillus thuringensius israelensis (Bti) in salt marshes, cattail marshes and stagnant waters.
Property owner permission would be required prior to applications. The cost — up to $25,000 — would include a survey of the areas in question. The control would be an annual cost if continued.
The question will go to voters at town meeting at 8:45 a.m. on Saturday, March 16, at the Great Cranberry Firehouse.
In August, Islesford resident Joseph Delafield submitted a petition with the signatures of more than 90 residents of Islesford that asked the town to “earnestly and fervently” undertake as soon as possible a program of mosquito control “in the interests of public health and safety, economic well-being and citizen comfort.”
Select board chairman Richard Beal said the mosquitoes were particularly vicious last summer.
Petitioners and town officials agreed that a control program should do no harm to lobsters and fishing in general.
“It’s not a simple thing to do, as far as getting rid of acres and acres of mosquito breeding areas,” said Beal.
“It’s pretty bad,” Delafield said in a recent phone interview. “There are times when it’s absolutely overwhelming.”
Delafield has been a summer resident of Islesford for 50 years; his wife has lived there since childhood. Some areas, he said, are enveloped by clouds of mosquitoes; the bites are vicious enough to cause bleeding sores for some.
“Little Cranberry Island should be a place where it’s a joy to go outside. It’s not,” he said. “It’s very difficult, even with insecticide, to do any gardening or to take a walk or to have a picnic.”
Petitioners are also concerned about the risk of West Nile virus and eastern equine encephalitis, and about the insect’s “chilling effect” on tourist traffic.
“The island benefits from the tourist industry fairly significantly during the summer months,” said Delafield. “I think people cannot help but be reporting back that it’s not much fun walking around. And I think there’s bound to be a significant economic impact on the tourist industry.”
It’s not a new problem. According to the town’s 2002 mosquito study, the Cranberry Isles were extensively ditched and drained in 1928 in an effort to control mosquitoes. A 1928 newspaper article quoted Major Edwin Skinner, the mosquito-control expert who led the project, who explained why the Cranberry Isles contain “the most prolific mosquito breeding, in proportion to their area, of any section in the Eastern States. This is primarily due to the fact that the ocean has thrown up great stone and sand sea walls. Through these the perigree tides seep or overflow the boundaries, thus leaving pools and ponds of salt water that soon stagnate and breed millions of mosquitoes.”
The town thereafter appointed a “mosquito commissioner” and maintained the ditches until 1956, when DDT was brought in. Aerial spraying, thought to have also killed frogs, bats, birds and other insects, was discontinued in 1962. Nothing was done from then on.
“Many of the ditches are now clogged and themselves serve as breeding pools for mosquitoes,” the 2002 study said.
The 2002 study came about when the town reopened the matter after two particularly bad summers and in light of the then-recent arrival of West Nile virus in Maine. Voters subsequently considered but rejected the use of larvacides in breeding areas. At the time, a local newspaper quoted lobsterman Warren Fernald’s alternative remedy: “Let’s just keep slapping and swearing. Now don’t that work?”
Now, through Delafield’s research, the town has identified pest management company Swamp, Inc., of Kittery, to do the job. Swamp entomologist Michael Morrison, as well as Maine Board of Pesticides Control pest manager Gary Fish, confirmed that Bti is nontoxic to lobsters.
In his proposal, submitted in December, Morrison said the control program would include four of the five islands that make up the town of Cranberry Isles — Great Cranberry, Little Cranberry (Islesford), Sutton and Bear.
“The islands have numerous mosquito breeding habitats including salt marshes, cattail marshes, woodland pools, stagnant ditches and other stagnant water habitats,” Morrison wrote.
Morrison said control should be centered on larvae breeding and stagnant water habitats. He said larvae can easily be eliminated.
Morrison said Bti has “been used successfully for many years.” Bti would be applied simultaneously with regular surveys, conducted over a seven-month period from April through early October, he wrote.
Morrison said wetlands management should also be part of the program.