Accabonac Mosquito Spraying Cut Dramatically Due to New Testing Partnership

With their mosquito dip cups, from left to right:  Legislator Bridget Fleming; John Aldred, East Hampton Town Trustee; Susan McGraw Keber, East Hampton Town Trustee; Mike Delalio, Environmental Technician of East Hampton Town; Matt Grasso, The Nature Conservancy; Kevin McDonald, The Nature Conservancy; Kim Shaw, Environmental Protection Director; and Tom Iwanejko, Principal Environmental Analyst of the Suffolk County Division of Vector Control
With their mosquito dip cups, from left to right: Legislator Bridget Fleming; John Aldred, East Hampton Town Trustee; Susan McGraw Keber, East Hampton Town Trustee; Mike Delalio, Environmental Technician of East Hampton Town; Matt Grasso, The Nature Conservancy; Kevin McDonald, The Nature Conservancy; Kim Shaw, Environmental Protection Director; and Tom Iwanejko, Principal Environmental Analyst of the Suffolk County Division of Vector Control

Environmentalists in East Hampton are celebrating an innovative program that has enabled the reduction of the spraying of Accabonac Harbor in Springs by 50 percent.

In 2017, Suffolk County Legislator Bridget Fleming brought together a cooperative team with representatives from The Nature Conservancy, Suffolk County Vector Control, the East Hampton Town Trustees, The Town of East Hampton and 10 volunteer citizen-scientists to collect mosquito samples throughout the harbor to give the county a much better picture of where mosquito spraying was needed.

The program was implemented for 11 weeks of the 2018 Suffolk County Vector Control spraying season, which runs from May 21 through Sept. 21.

Led by Nicole Maher of The Nature Conservancy; East Hampton Trustees Susan McGraw Keber and John Aldred; and Mike DeLalio, an Environmental Technician with the Town of East Hampton Planning Department, program participants collected dip samples at almost 6,000 GIS data points over the course of the summer to test for the presence of mosquito larvae.

Dip data was identified by GIS location, larval stage and number at each stage, and pupae presence. The information was sent to The Nature Conservancy for review and a weekly data set was then forwarded to Suffolk County Vector Control.

Vector Control staff mapped the larval distribution and reviewed the data for a treatment decision by the Director of Vector Control Tom Iwanejko. If treatment was considered necessary, a revised map was sent to the helicopter pilot to adjust the long-used “spray blocks” to target only the hot spots within the treatment area.

According to Legislator Fleming’s office, results of the sampling “clearly demonstrated that the need for pesticides in certain locations was significantly lower than previously thought. The survey group detected mosquito larvae in only 544 of 6,000 samples.

Data from the team showed that of the estimated 190-acre treatment block, only 70 acres showed breeding. Based on these data, the area to be sprayed was less than half.

Ms. Fleming’s office estimated that the reduction in spraying saved the county $18,000 this year.

Instead of treating the entire spray blocks (crosshatched areas numbered on the map), only the hotspots with the mosquito larvae identified by weekly surveillance were treated resulting in much smaller treatment footprint (violet colored blocks) on the marsh. The 2018 aerial applications were targeted toward areas with heavy mosquito breeding.
Instead of treating the entire spray blocks (crosshatched areas numbered on the map), only the hotspots with the mosquito larvae identified by weekly surveillance were treated resulting in much smaller treatment footprint (violet colored blocks) on the marsh. The 2018 aerial applications were targeted toward areas with heavy mosquito breeding.

“After years of disagreement among stakeholders about methoprene use and protecting public health, this thoughtful program represents a groundbreaking step toward reform of standard pesticide application and has reduced methoprene use by 50 percent,” said Ms. Fleming at an Oct. 9 press conference overlooking Accabonac Harbor announcing the success of the program. “This approach holds the promises of cost savings and environmental protection, not only in Accabonac Harbor, but in other areas of Suffolk County as well.”

“The dedicated team of citizen scientists who sampled each week delivered an in-depth study of the mosquito breeding locations and extent at Accabonac that can be used as a stepping stone toward restoration planning of the marsh,” said Vector Control Director Tom Iwanejko. “I am greatly encouraged by this partnership and hope we can continue to expand on this cooperative effort with East Hampton and throughout the County.”

During 2018, Vector Control shifted more spraying to a quick acting and non-residual Bti and methoprene granule product, moving away from liquid sprays, which reduces drift issues and allows the helicopter pilot to target the upland marsh edge. The helicopters used for spraying travel just 50 feet above the ground to ensure accurate applications.

The treatments targeted the points identified by the team, which showed that mosquito breeding was predominantly along the upper marsh edge, moving larvicide application away from the harbor and potential direct contact with the bay.

The team is also identifying hotspots where movement of water can be achieved with simple wetlands restoration techniques to reduce breeding areas.

For instance, during initial surveying in 2017, the team observed a sunken boat sitting in shallow waters that was harboring larvae breeding.

The East Hampton Town Trustees removed the boat, eliminating the breeding area, and the need for larvicide applications at that spot.

“This was a very successful pilot project proving that good science can lead to good outcomes, mapping and communicating the location of mosquito breeding provided a sound basis for the county to reduce its aerial pesticide applications,” said Dr. Nicole Maher, Senior Coastal Scientist at The Nature Conservancy in New York. “We look forward to helping our partners transition to a more operational model and to exploring minimally-invasive restoration at the breeding hot spots that could both eliminate the mosquito breeding and increase the marsh’s resilience to sea level rise.”

Beth Young

Beth Young

Beth Young built her first boat out of driftwood tied together with phragmites behind her family’s apartment above the old Mill Creek Inn in Southold. Nowadays, she spends most of her time kayaking, learning about shellfish, writing newspaper stories, trying to sail a Sunfish, and watching the way the bay changes from day to day. You can send her a message at [email protected]

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