Responding to many years of widespread concern regarding potential harmful effects of pesticide spraying over 190 acres of wetlands at Accabonac Harbor off Gardiners Bay in East Hampton, Legislator Bridget Fleming brought together a cooperative team of The Nature Conservancy, Suffolk County Vector Control, the East Hampton Town Trustees, The Town of East Hampton and 10 volunteer citizen-scientists to address the issue.
Initially conceived in 2017 to reduce the risks associated with pesticide applications while still providing a high level of public health protection, the program was fully implemented for 11-weeks of the 2018 spraying season that runs from May 21 through September 21. Led by Nicole Maher of The Nature Conservancy, East Hampton Trustees, Susan McGraw Keber and John Allred, and Mike DeLalio, Environmental Technician with the Town of East Hampton Planning Department, program participants collected dip samples at almost 6,000 GIS data points over 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 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 spray blocks to target only the “hot spots” within the treatment area.
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, approximately 70 acres showed breeding. Based on these data, the area to be sprayed was less than half.
The reduction saved the County an estimated $18,000 from reduction of both pesticide usage and helicopter hours spent treating the site. In addition, the treatments targeting the points identified by the team showed that breeding was predominantly along the upper marsh edge, and applications were therefore moved away from the harbor and potential direct contact with the bay.
The team will continue to identify 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. East Hampton Trustees removed the boat, eliminating the breeding area, and the need for larvicide applications at that spot.
Based on the surveying program, pesticide applications decreased by 50% in 2018. On 4 separate weeks during the 11 weeks season, the decision was made not to spray at all. During 2 of those weeks, surveying had been unnecessary because of dry conditions. During the 2 other weeks, data returned by the team supported the decision not to spray.
“I am extremely proud of the work conducted at Accabonac Harbor. 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%. 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. I look forward to exploring efforts to recreate this program throughout the County to engage in public/private partnerships and to further reduce the amount of pesticides released in the environment, and to save even more tax dollars.” said Legislator Bridget Fleming.
“This cooperative project at Accabonac Harbor not only resulted in cost savings to the County, but reduced our pesticide applications and acreage requiring aerial treatment significantly. 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. 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,” said Tom Iwanejko, Director of Suffolk County Vector Control.
The helicopters used for spraying travel only fifty feet above the ground to ensure accurate applications. Additionally, the materials used for the pesticide are approved both by the New York State Department of Environmental Conservation and the United States Environmental Protection Agency. 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. However, when large areas are sprayed without detailed surveying, the potential of unnecessary spraying poses a threat to the groundwater, wildlife and residents, and it increases the burden on taxpayers.
“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.”
Because of the cooperative effort at Accabonac Harbor, the pesticide application process is more comprehensive and cost-effective, and poses less potential environmental harm.
Residents in the area experience benefits, such as reduced contamination potential, taxpayer savings, and a decreased risk of contracting mosquito-borne disease.
Aerial treatments in 2018
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.