The Carlisle Mosquito Online

Friday, January 26, 2001


Board of Health revisits mosquito control

David Henley, superintendent of the Eastern Middlesex Mosquito Control Project (EMMCP), was invited to the January 16 meeting of the board of health to describe his project's services, discuss Carlisle's potential participation and answer questions. Henley emphasized that unlike the Central Massachusetts Mosquito Control Project (which the town had rejected at the Special Town Meeting) the town would have more choice and control over the costs and services.

Mosquito control services

The services that can be provided by EMMCP include:

· mosquito and wetland surveillance

· larval and adult mosquito control

· ditch maintenance

· public education.

Prior to control operations, larval mosquito data is collected. Wetland surveys are conducted and entered into a database using input from local officials and residents. Adult mosquito population is determined by using traps set at different points around a town.

The larval control uses helicopters to apply Bti (Bacillus thuringiensis israelensis) and Altosid, larvacides considered environmentally safe, to large wetland sites each year in April. Aerial applications may also be applied the summer following flooding rains. Small wetlands (less than three acres) are treated by field workers applying Bti using a truck-mounted sprayer or portable sprayers.

In the event of an outbreak of eastern equine encephalitis or West Nile virus, the project can spray Resmethrin, a synthetic pyrethrin, at night to control adult mosquitoes. Henley pointed out that in the event of such an outbreak it would be useful to be a member of EMMCP, which would have the database and survey information and be able to coordinate spraying with the town board of health and the state. Additional information on the project can be found on the web:

EMMCP membership and cost

For the admission of a new town the EMMCP uses the following criteria:

1. The new town should be contiguous to the current members of the EMMCP.

(Bedford is a member.)

2. Admission must be beneficial to both the current membership and the new town.

3. The town must have a mandate (from town meeting) that it will be a long-term participant.

The cost per year is a fixed cost, estimated to be $4,504 per year for FY2001, plus an additional cost for the specific services the town receives. The current labor charges are $50/hr. There is also a one-time charge for capital equipment which is reimbursed 50 percent over three years after the second year. Henley recommends that the town consider an appropriation in the range of $30,000 per year for a comprehensive mosquito control program.

Does mosquito contol work?

Board chairman Steve Opolski said that he had been looking diligently for any study which showed that spraying or larvaciding mosquitoes had any positive effect and he had not found any.

Tim Fohl of South Street said that he believes from personal observation that aerial spraying in the early 1960s resulted in severe mosquito population increases by 1969. When spraying was discontinued for the next 15 or 20 years, bigger bugs and small birds, which are mosquito predators, returned. Recently he noticed you could go out at night and things weren't so bad. Fohl is concerned that spraying or mosquito control might reverse the pattern again.

Henley observed that the weather patterns have a lot to do with mosquitoes also. The pattern in 1987 to 1992 was very damp and the mosquito population was high, but we had some drought years in 1993, '95, '97 and '99, and a lot of the wetlands dried up.

Board of health physician Dr. Claudia Talland stated that the board's mission was the control of disease such as equine encephalitis or West Nile virus, and not reducing the mosquito nuisance. Talland stated that although one bird infected with the West Nile virus was found in Carlisle, there have been no documented cases of human infection in all of Massachusetts.

The lengthy discussion was summed up by Tony Mariano, who asked, "Aren't we going backwards moving towards this? We are looking at a solution before knowing the problem."

2001 The Carlisle Mosquito