Board of Health meets with state officials to discuss mosquito control

Officials consider dragonflies and goats over spraying salt marsh

By Barbara Taormina

REVERE – The Board of Health was joined at their last meeting by members of the staff of the Northeast Massachusetts Mosquito Control and Wetlands Management District, who presented an overview of the work being done to control mosquito populations and any risk of West Nile virus and Eastern equine encephalitis. District Director Barry Noone and Entomologist Kimberly Foss described their program of integrated pest management that begins with surveillance, the tracking and trapping of mosquitos throughout the district. Once captured, the bugs are frozen and sent to the state for testing for any trace of the viruses mosquitoes transmit to humans.

According to Foss, the 54 species of mosquitos in Massachusetts pick up viruses from birds and pass the diseases to humans when they bite. Noone explained that traps collect mosquito lava and adult mosquitos. From March to September, teams go out to different sites in salt marshes and flood areas to conduct surveillance of mosquito breeding. They are able to determine if the mosquitos are a risk to humans and what, if any, intervention should occur.

Close attention is paid to catch basins, which are cleaned and monitored. Mosquitos often breed in artificial containers, and district workers remove 600 to 800 tires every year.

Some salt marsh mosquitos lay their eggs in wet, muddy areas, such as stagnant ditches along salt marshes. High tides flood these areas and trigger the hatching of mosquito eggs. Salt marsh mosquitos are known for being aggressive day biters. Without treatment, they can have massive breeding numbers from June to September and are an extreme coastal nuisance. If larval counts are high, areas are treated with a bacterial larvicide, which, like all of the chemical treatments used by the district, pose a low risk to humans, wildlife and pollinators.

The district recommends barrier spray treatments for public areas, such as parks, athletic fields and schools. A barrier spray is applied to surrounding trees, bushes and vegetation, which reduces mosquitos for several weeks. The spray is applied at night when mosquitos hunker down for the day. According to Noone, residents need to stay off fields after they’ve been sprayed but areas are safe for people to visit by the next morning.

Property owners who are concerned about mosquitos can call the district. Staff will come and inspect a property to find any areas or objects likely to attract breeding mosquitos. Birdbaths, kiddie pools and pet dishes – anywhere water can collect – are common culprits.

Homeowners who have an abundance of mosquitos in their yard can contact the district and request that their property be sprayed. A pickup truck mounted with an Ultra-Low Volume (ULV) aerosol generator (sprayer) will come to a home after dark and pull into the driveway. The spray trucks deliver a 300-ft. column of mist spray to the property, which kills adult flying mosquitos. This technique, called adulticide, provides temporary control over flying mosquitos and will diminish mosquito populations that could potentially be carrying virus.

Health Board member Viviana Cataño asked about natural remedies. She had questions about using goats to graze on the phragmites, an invasive marsh plant favored by mosquitos for nesting and breeding, which was used before. Noone didn’t think goats would have the desired impact and said the district mows down the phragmites in October and grinds it to pulp. Cataño also asked about bringing in some dragonflies, which eat mosquitos. Foss said dragonflies do feed on mosquitos but there is other food they prefer. And Foss said dragonflies would have to be imported from other states and they would pose a threat to local dragonfly populations.

The district maintains a user-friendly website at https://www.nemassmosquito.org/ where residents can request home inspections, truck spraying and removal of abandoned tires. The site also has a link for any resident who wants their home to be excluded from any widespread spraying or treatment. There’s a list of all chemicals and pesticides used and information about insecticides and things to avoid to escape mosquito bites.