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    FAQs: Aerial Mosquito Spraying






    Why does the Onondaga County Health Department conduct aerial spraying for mosquitoes?

    The aerial spray is done in an attempt to interrupt the virus cycle in the mosquito population. Reducing the number of mosquitoes (although it is temporary) can reduce the number of mosquitoes available to transmit virus to humans.

    Does the Onondaga County Health Department ever do

    truck spraying for mosquitoes?

    Truck spraying is not an effective way to kill mosquitoes in the Cicero Swamp.  Spraying while driving around the perimeter of the swamp will not penetrate deep enough into the wooded areas. However, truck spraying is occasionally used in select neighborhood areas as a supplement to the aerial spraying or in areas other than the Cicero Swamp location, when a mosquito virus is found in a trap.

    How does the Onondaga County Health Department determine when aerial spraying for mosquitoes should occur?

    The decision to spray is based on several factors including the number of mosquitoes found in mosquito surveillance traps and the presence of virus in the mosquitoes (West Nile virus and/or Eastern Equine Encephalitis virus). All spraying decisions are made with assistance from the New York State Department of Health (NYSDOH) and the New York State Department of Environmental Conservation (NYSDEC).

    How many times per season does the Onondaga County Health Department do aerial spraying for mosquitoes?

    There is no set number of aerial sprays per season. The number of mosquitoes present, along with the presence of virus, will guide decisions about spraying. There may be some years when no aerial spraying is performed due to low mosquito numbers and because there is no virus found in the trapped mosquitoes. 

    What is the pesticide used for aerial mosquito spraying?

    The pesticide used for aerial mosquito spraying is Kontrol 30-30. This products is specifically used for the control of adult mosquitoes in outdoor residential and recreational areas. It contains permethrin and piperonyl butoxide as active ingredients. Permethrin is a man-made pyrethroid insecticide that can also be found in other pesticide products used indoors and on pets to control ticks and insects, such as fleas and ants.

    Are the pesticides used for aerial spraying safe for humans and pets?

    Pesticides are applied at very low concentrations to control mosquitoes. It is unlikely that adverse health effects will occur as a result of this use for most people. However, some people may experience health effects, therefore, take steps to minimize your exposure to the pesticide by remaining indoors and closing your windows during the spraying. You may call our Mosquito Control office at 315.435.1649 for more information or for a copy of the pesticide label.

    Are residential areas sprayed?

    The aerial spraying does not target any residential areas. There are several residential neighborhoods at the edge of the Cicero Swamp shown on our spray map and although the contractor does not spray directly over these areas, we include them because of possible drift. There are a number of single homes in the spray area and these are indicated on the spray map

    What precautions should be taken by residents in the spray area?

    If you live in the spray area, stay indoors during spraying and your keep windows closed for one hour after the spraying is completed. Keep your pets indoors if possible. Set your window air conditioners to circulate indoor air. It is safe to use your central air conditioning. Remove children’s toys that are outdoors, any outdoor furniture, and clothes from outdoor clotheslines. If you are driving during the spraying, close your car window and car vents. After the spraying, rinse your garden vegetables before eating. If clothes or toys were left outdoors during spraying, wash them thoroughly with soap and water and launder the clothes before wearing.

    Why does aerial spraying sometimes get postponed due to weather?

    Certain circumstances may reduce the effectiveness and accuracy of the application such as wind over 10 mph or rain occurring during spraying or soon after. The permit granted to us by the NYSDEC specifically states that spraying cannot occur if there is a fifty percent or greater chance of a rain in the forecast during the scheduled time of spraying, or within four hours after. The reason for this is to prevent pesticides from getting into wetlands, near-by areas, and bodies of water in storm water runoff. Also, according to the product label, air temperature during application must be at least 50 degrees F.

    Are there other factors as to why spraying may be postponed?

    In addition to weather conditions, spraying may be postponed due to mechanical failure of the plane or other factors out of the spray contractor’s control.

    What company is doing the aerial spraying for Onondaga County? 

    Currently, the company doing the aerial spraying is Duflo Spray-Chemical, Inc.

    Does the Onondaga County Health Department do aerial spraying for “comfort” only?

    The Health Department does not spray for comfort. Spraying will only occur if virus is present or if the number of mosquitoes and conditions are present which would indicate a public health threat.

    After the aerial spraying, do I still need to protect myself from mosquitoes?

    Yes, always use personal protection when you are outdoors throughout the season until there is a frost by covering up and using mosquito repellent. Also, continue to reduce mosquito breeding grounds by getting rid of standing water on your property. Click here to learn more.

    Do you have to wait until you find evidence of West Nile virus or EEE virus before considering aerial spraying?

    We do not have to wait to find evidence of disease before spraying. Our NYSDEC permit allows us to consider spraying either when virus is found in mosquitoes or “when there is a substantial peak in mosquito activity earlier in the season which generally precedes an upsurge in virus activity and increases the potential for occurrence of human cases of mosquito-borne disease”.

    How do you inform the public that spraying will happen?

    Residents who live in the spray area will be contacted by phone through the 911 emergency notification system. Spraying will also be announced through the media (television, radio, newspaper) as well as on the Health Department's website and Facebook page.


    For more information please call our Mosquito Control Program at 315.435.1649. We will answer all of your questions and add them to our FAQs!



    New York State Department of Health
    New York State Department of Environmental Conservation 


    Updated August 2019



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