Deerfield eyes pheromone spray to stymie mosquito reproduction

Last modified: Friday, July 11, 2014
DEERFIELD — As the peak of mosquito season draws near, Deerfield town officials are looking for ways to control the insect’s population growth and are urging residents to take measures to protect themselves from being bitten by the bugs, which may carry infectious diseases.

Board of Selectmen Chairwoman Carolyn Shores Ness said the town plans to coordinate with neighboring communities to apply for a grant to purchase equipment that will allow them to apply a pheromone- based spray to mosquito breeding grounds.

The spray, she said, will sterilize the mosquitoes and keep their numbers down, but is not harmful to humans or pets. Ness said the town is waiting to see how effective similar methods being used in communities on Cape Cod are before making the purchase.

“We don’t want to invest in the equipment if it isn’t necessary or effective,” she said. “If it works out in the eastern part of the state, then it makes sense to invest in this.”

She said Northampton and Hatfield implemented testing programs last year that detected the presence of the mosquito-borne illnesses West Nile virus and Eastern equine encephalitis, the latter of which killed a horse in Belchertown and led to the cancellation of numerous outdoor events in 2012.

“We know that it’s around and it’s residual from year to year,” Ness said.

Ness said it is often difficult and expensive to get mosquito testing from the Department of Public Health in western Massachusetts. This prevents local towns from getting a clear picture of what types of diseases or viruses are present in local mosquitoes, so that investing in the spraying equipment is a better response to the problem.

Dr. Catherine Brown, the DPH’s state public health veterinarian, said the department does offer testing to Franklin County towns like Deerfield, but the mosquitoes first need to be collected, sorted into species groups and sent to the DPH by the projects, which operate under the Department of Agricultural Resources.

“They have the local expertise to know the lay of the land and where the best places to set traps for catching mosquitoes are,” Brown said. “A significant portion of the state does not subscribe to mosquito-control projects. It’s a problem for us and a problem for them from a mosquito-control standpoint.”

Brown said that once a town has been able to col­lect the mosquito specimens, the DPH is able to work with it to identify any illnesses they may be carrying.

Brown said she hasn’t seen any cases of West Nile or EEE so far this year, but expects the first mosquito to test positive “any day now.”

“Historically, that happens in early August into September,” she said.

Raising awareness

Ness said the town is also trying to increase awareness of the dangers of mosquito-borne illnesses among residents and of protective measures, such as draining any standing water that collects in their yards after rainstorms and developing habits such as using insect repellent, wearing long-sleeve shirts and pants and limiting outdoor activities at dusk and dawn, when mosquitoes are most active.

“We don’t want people to be afraid to go outside, but when mosquitoes become a big problem like this, you have to get people to be more proactive,” said Ness. “If everyone polices their backyards, then it won’t be as bad. It’s really a hassle when you have rain every day.” Even small amounts of standing water in old tires, folds in plastic tarps and buckets can house mosquito larvae.

Ness said the town is also working to control the area’s mosquito population through the use of Mosquito Dunks tablets, a biodegradable larvicide that floats on top of standing water and kills mosquito larvae for about a month.

Town officials, including police, fire and highway department personnel, carry the tablets with them, tossing them into standing water when needed and logging the time and location of each application into a GPS system.

She said using the tablets costs the town a little less than $5,000.

“We’re being a lot more formalized about it this year,” Ness said of the program. “It’s a lot more like scheduled maintenance.”

For now, she says, remaining vigilant and developing good habits is the best defense residents have against the viruses.

“This is a new reality with all these bugs,” she said. “It’s all simple stuff that can have an impact.”