Helicopter application of mosquito larvicide planned at Beaver Brook Reservation

The East Middlesex Mosquito Control Project will conduct a helicopter application of biological larvicide later this month to reduce mosquito populations in a large wetland area of Beaver Brook Reservation in Waltham.

The treatment will occur between April 21 and May 1, weather permitting. Crews will apply Bacillus thuringiensis var. Israelensis (bti) in granular form from a low-flying helicopter directly over the wetlands. Officials said residents do not need to take any special precautions during the operation.

Bti is a naturally occurring bacterium found in soil and is considered relatively non-toxic by the U.S. Environmental Protection Agency. It specifically targets mosquito larvae and a few related aquatic insects from the fly family. The product, VectoBac GS (EPA Registration No. 73049-10), breaks down quickly in the environment and does not harm people, pets, fish or wildlife.

Mosquito control officials said the application is part of the region’s annual effort to curb mosquito-borne illnesses such as West Nile virus and Eastern equine encephalitis, which have been detected in Eastern Massachusetts in recent years. Reducing mosquito populations early in the season helps limit potential disease spread later in the summer.

Residents seeking more information can contact the East Middlesex Mosquito Control Project at 781-899-5730 or visit mass.gov/mosquito-control.