Suffolk County Vector Control conducts mosquito control applications based on elevated mosquito counts or when the Suffolk County Health Department identifies an area at risk for West Nile or Eastern Equine Encephalitis (EEE) virus activity. Mosquito control spray applications effectively reduce the mosquito population, thereby decreasing the risk of disease transmission to the public.

Residents are encouraged to sign up for the SuffolkAlert system to deliver timely messages directly to homes and business in the event of a large scale emergency or special event that may impact an area. Vector Control utilizes this notification system to send adult spray notification to residents within a treatment area using the SuffolkAlert system. Suffolk County also posts the spray notifications on the Suffolk County website under the County News alerts and to social media including Facebook and X by following Suffolk County Health.

Mosquitoes have four stages in their life cycle: egg, larva, pupa, and adult. The first three stages are aquatic. The female mosquito first lays eggs on or near the water surface. The eggs may hatch a few days, months or even years later and the larvae will emerge from the egg. After several days, the larvae pupate and emerge as an adult mosquito.

Because three (3) of the four (4) life stages of a mosquito are aquatic, the best way to control them is to target the aquatic stage. By denying them the water they need to develop, mosquitoes cannot complete their life cycle, and they die. For this reason, we ask the public to eliminate standing water around the home and to report areas of stagnant standing water for treatment.

Control of mosquitoes while in the aquatic larval stage is the most efficient stage for mosquito control. Larvicides are products used to eliminate the immature mosquito. Larvicides are applied directly to standing water that holds immature mosquito larvae. Larvicides used in Suffolk County are classified by the EPA as biopesticides, which are biologically found in nature. Larvicides reduce the mosquito population by limiting the number of biting adult mosquitoes produced from a treated source. Larvicides we apply can be as granular pellets, liquid or briquets.

Adulticides used in Suffolk County are for rapid reduction of adult mosquito populations. This may be necessary when the number of biting-adult mosquitoes overwhelms a community or there is a threat of disease transmission in an area. Our sprayers use an ultra-low volume (ULV) method of spraying. ULV spraying is the process of putting very small amounts of material into the air as a super fine mist of droplets. These droplets are designed to float on the air currents and eliminate flying mosquitoes that come directly into contact with the drifting droplets. ULV spray can be applied from backpacks, trucks or helicopters. Adulticides act to immediately reduce the number of adult mosquitoes in an area and are non-residual.

For larval mosquito control, Suffolk County utilizes Bacillus thuringiensis israelensis (Bti) and Bacillus sphaericus, both are soil bacteria-based products. The bacteria must be ingested in sufficient quantity to kill the larvae. We also may treat using the biopesticide s-methoprene, an insect growth regulator. Methoprene is absorbed through the skin and prevents the mosquito larvae from becoming an adult mosquito.

Adult mosquito control products used by Suffolk County may include pyrethrins and pyrethroids, both of which can be formulated with a synergist chemical to increase their efficacy:

• Pyrethrins are the active ingredients in pyrethrum, an extract of the flower Chrysanthemum cinerariifolium. Pyrethrins are natural insecticides that act by blocking chemical signals at nerve junctions.
• Pyrethroids are a synthetic version of pyrethrins that also act by blocking chemical signals at nerve junctions. The adult mosquito control pesticide Anvil (sumithrin) that Suffolk County uses is a pyrethroid based product.
• Piperonyl butoxide (PBO) is a synergist that is usually incorporated with pyrethrins and pyrethroids. PBO enhances the effect of these insecticides by inhibiting enzymes in mosquitoes that can break down the insecticide. This allows the insecticides to be effective using less active ingredient than would otherwise be required.

The U.S. Environmental Protection Agency (US EPA) must approve the use of each insecticide and the New York State Dept of Environmental Conservation (NYSDEC) must approve their use in NY. Before pesticides are registered by the US EPA or NYSDEC, they must undergo extensive testing for environmental impacts as well as test for acute and chronic health effects.

Suffolk County underwent a full environmental review of our mosquito control program including all pesticide materials used. The review team did not find impacts to lobsters, bees or other insects from the use of methoprene or other larvicides used by Vector Control. Recently, Suffolk County had researchers from Stony Brook University conduct a follow-up scientific literature review of methoprene and concluded: “Several recent reviews, including large risk assessments conducted by Canada and New Zealand, as well as approved uses in the European Union, support the use of biorational pesticides in general and Methoprene in particular, finding it to be among the safest pesticides available for control of mosquito populations”.

Mosquito dunks are made with the pesticide Bacillus thuringiensis israelensis (Bti), a pesticide material Vector Control does use. Dunks are marketed for homeowner use in small containers and fish ponds.

While birds, bats and dragonflies may consume some mosquitoes, it is only a small portion of their diet. Birds feed during the day, when most mosquitoes aren’t active. Bats may eat a few mosquitoes, but studies have been shown to only be 1-3% of their diet. Bats mainly feed on beetles, moths and other larger flying insects. Bats are also considered the high-risk carrier of rabies on Long Island. Care should be used in placing bat houses near areas where people may become exposed to their droppings.

Dragonflies are highly predatory and do eat mosquito larvae during their aquatic stage and adult mosquitoes once the adult winged dragonfly emerges from the water and can fly. Dragonfly nymphs during the aquatic stage are cannibalistic, so stocking them would result in only a few surviving adults. Adult dragonflies are often found in large numbers in the marsh. Their emergence in the summer is often timed when large numbers of saltmarsh mosquitoes also emerge. The dragonfly adults, while predatory on mosquitoes and other insects are outnumbered by the millions of mosquitoes that often emerge en masse.

The only effective natural predator of mosquitoes are small fish, including killifish in salt marshes and fathead minnow and mosquito fish/gambusia in freshwater. Release of fathead minnow fish is restricted and limited by the NYSDEC in Suffolk and invasive gambusia release is not allowed. These fish can predate on young tiger salamanders and other critically impacted native species or may spread disease to native fish.

Using Integrated Mosquito Management wetland restoration techniques, Vector Control has worked to build coastal resiliency and allow for improved mosquito control using natural killifish found in our coastal wetlands. These projects have allowed for natural mosquito control and to reduce our need for larvicide applications at these sites, while restoring lost wetland functions and values.

The CDC has guidance for all aspects of larval and adult mosquito control. For their updated guidelines and planning resources that provides detailed guidance about the use of mosquito control measures, including suggestions for an elevated response and the actions that are possible at different levels of virus activity, see the CDC resource links here: www.cdc.gov/mosquitoes/mosquito-control/index.html

The EPA has determined these products do not pose a risk to you or your family when used per the label directions. In fact, some flea and tick control products we may use for in our homes or on our pets may contain the same active ingredients. For adult control, the approved application rate we utilize for Anvil 10+10 (EPA #1021-1688-8329) is 0.62 FL, or roughly 1 tablespoon per acre. For more information on insecticides and public health, consult the U.S. Environmental Protection Agency, which oversees the registration of these chemicals. The National Pesticide Information Center (NPIC) and the Centers for Disease Control and Prevention also maintain mosquito control resources and pesticide information.

The Suffolk County "No-Spray" Registry lets residents opt out of adult mosquito control spraying (aerosol and fog treatments) on their property. This law ensures that your property and a 150-foot buffer around it are avoided during ground spraying. Please note, the registry does not include mosquito larval control or any spraying conducted during a public health emergency. Click this link to view and download the form: Do Not Spray Request Form

If you are experiencing serious health problems for any reason, it is important to contact your health care provider promptly or call 911 for emergency assistance. Residents can request to be placed on our ‘Do Not Spray’ registry by completing the form that can be found on our No Spray Law Registry page and returned to us.

Vector Control uses public health pesticides approved by the US EPA for use on and over outdoor residential and recreational areas, including areas where people and pets may be present outside. While it is not necessary to totally avoid areas being treated, we do recommend limiting exposure whenever possible. The spray will quickly dissipate from the treated area and degrades rapidly in sunlight.

The materials used for controlling mosquitoes, when used in accordance to the label, are not harmful to pets. Many times, it is the same materials used to treat cats and dogs for fleas and ticks. However, if you choose to reduce your pet’s exposure, keep them inside during spray application.

While it is not necessary to close doors or windows, we do recommend limiting exposure when possible. The spray will quickly dissipate from the treated area and degrades rapidly in sunlight. You do not need to turn off the air conditioner, but may choose to close the outside ‘fresh air’ vent; if it is open.

Under the NYS Public Health Law and Suffolk County Charter, protection of residents from mosquitoes can be carried out by Vector Control crew on private property. Crews may be responding to the complaint of standing water from a neglected swimming pool, containers or other sources of standing water. Vector Control crews will try to work with the property owner, but can issue a notice for a potential health violation if the owner doesn’t correct the issue. A Suffolk County Health Services Public Health inspector will follow up on the complaint and the violation can result in fines or a court appearance if the owner continues to neglect the mosquito source violation.

Your swimming pool and items found in your yard will not be affected, but you may choose to rinse off outdoor items and children’s toys.

Just as you normally would with store bought produce, residents should wash all home-grown fruits and vegetables before eating them.

Adult mosquito control spraying is conducted using ULV applications at label rates that should not impact bees or other larger insects. Anvil is applied by ULV in fine droplets, which break down quickly in the environment. Since the product must hit a mosquito while it is in flight to have an effect, spraying is scheduled when mosquitoes are actively flying and other insects, such as bees and butterflies, are not active. Applicators are trained to avoid directly targeting blooming plants, bee hives, or other areas where bees and butterflies may congregate.

Beekeepers can register hive locations with Vector Control as a ‘Do Not Spray’ location and we will avoid treating near the hives during ground spraying. To request that your hive location(s) are placed on our ‘Do Not Spray’ registry, complete the Do Not Spray form found on our No Spray Law Registry page and returned the form to us. If you maintain hives on multiple properties, each location needs to be registered on a separate ‘Do Not Spray’ form with the required parcel tax map information for the hive. Beekeepers registered with Vector Control will be notified 24 to 48 hours before an aerial spray event near a hive, so that hives can be covered and protected.

If residents are still concerned about their hives, and bees are currently bearding on the side of the hive, the hive can be draped in wet burlap. The burlap is wet with water and then draped like a curtain over the hive with an opening in the front for bees to enter and exit.

Questions concerning specific insecticides can be directed to the U.S. Environmental Protection Agency, as this agency has responsibility for the registration of insecticides. Many issues are addressed on the EPA’s Mosquito Control Web site.

The National Pesticide Information Center (NPIC) provides insecticide information and questions about the impact of insecticide use on human health. NPIC is cooperatively sponsored by Oregon State University and the U.S. Environmental Protection Agency.

NPIC can be reached online or toll-free: 1-800-858-7378. The Center for Disease Control and Prevention have also posted guidance and planning resources online.

All pesticides used by Suffolk County Vector Control are registered by the NYS Dept of Environmental Conservation and are used under permit by NYSDEC licensed applicators.

Additional information on the Vector Control program and list of materials used in Suffolk County can be found on our website – Suffolk County Vector Control

The Suffolk County Health Arthropod-Borne Disease Laboratory carries out surveillance and education concerning arthropod-borne diseases in Suffolk County, including mosquitoes and ticks. The Arthropod-Borne Disease Laboratory conducts surveillance (collection and testing) of ticks and mosquitoes to determine the distribution and prevalence of the diseases they spread. They also provide education services to residents about the personal protection measures they can take to prevent tick and mosquito bites.