Westchester Land Trust (WLT) began targeted mosquito larvae management at Otter Creek Preserve following the issuance of a permit from the New York State Department of Environmental Conservation (NYSDEC).

What is happening?
Beginning July 1, a New York State-licensed applicator began applying a biological larvicide containing Bacillus thuringiensis israelensis (Bti) in granular form to the preserve’s “eight ponds” area. This is the same area where mosquito larvae treatments were conducted by the Village of Mamaroneck for more than 35 years.

The treatment targets mosquito larvae before they become biting adult mosquitoes. Because it interrupts the mosquito life cycle, it takes some time before visitors notice a reduction in mosquito activity.

Why is WLT doing this?
Otter Creek Preserve provides important wildlife habitat as the largest privately held saltwater marsh in Westchester County, while also serving as a beloved public preserve. This targeted treatment is intended to help manage mosquito populations in the historic treatment area while minimizing impacts on the surrounding ecosystem.

What is Bti?
Bti (Bacillus thuringiensis israelensis) is a naturally occurring soil bacterium that has been used for decades to control mosquito larvae. At Otter Creek, it is applied as a granule directly to standing water where mosquito larvae develop and is designed to affect specific fly larvae, including mosquitoes, before they emerge as adults.

This is not an aerial spray or truck-mounted adult mosquito spraying program. The treatment is limited to targeted applications in the designated areas.

Where is the treatment occurring?
Treatment is limited to the preserve’s “eight ponds” area, consistent with the historic mosquito management program previously conducted by the Village of Mamaroneck.

Will I notice results immediately?
No. Because the treatment targets mosquito larvae rather than adult mosquitoes, it may take several weeks before visitors experience reduced mosquito populations.

Who performs the treatment?
Applications are conducted by a New York State-licensed pesticide applicator under a NYSDEC-issued permit and contracted by Westchester Land Trust.

Media and Community Inquiries
For questions regarding mosquito management at Otter Creek Preserve, please contact:

Janelle Robbins | Vice President of Conservation, Westchester Land Trust
janelle@westchesterlandtrust.org | 914-234-6992 ext. 16

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About Westchester Land Trust

Westchester Land Trust works with public and private partners to preserve land in perpetuity and to enhance the natural resources in Westchester and eastern Putnam counties—a densely populated region under persistent threat from the pressures of development. Founded in 1988, WLT has preserved 9,622 acres of open space. More than 1,360 acres of land are owned by the organization which are free and open to the public year-round. WLT was one of the first land trusts in the nation to receive accreditation through the Land Trust Accreditation Commission.