Adult Mosquito Treatment Frequently Asked Questions

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• What is adult mosquito control?

  Adult mosquito control is a combination of techniques used by the County of San Diego Department of Environmental Health and Quality Vector Control Program (VCP) to rapidly reduce adult mosquito populations especially when a significant risk of disease transmission has been detected in an area. Pesticides that kill adult mosquitoes are called adulticides and are applied by certified vector control technicians to lower mosquito populations and reduce the risk to public health. The Environmental Protection Agency (EPA) has determined that when used in accordance with the label, Ultra-Low Volume (ULV) adulticide sprays are not harmful to people or pets.

  Applications of mosquito larvicides that kill mosquito larvae before they can grow into biting adults may also be used along with adulticides to keep mosquito levels low. 

• What are the benefits of adult mosquito control?

  Adult mosquito control works very quickly to reduce the numbers of adult mosquitoes in a localized area. This can provide immediate relief from mosquitoes and help prevent the spread of disease. Examples of diseases spread by mosquitoes include West Nile, Zika, dengue, chikungunya, and yellow fever. 

• How will I know if an adult mosquito control treatment is going to take place in my neighborhood?

  At least 24 hours prior to treatment, signs will be placed in the neighborhood and door hanger notifications will be placed on properties that will be treated. Additional information is available here and by calling the County of San Diego Vector Control Program at (858) 694-2888. 

• What products are used for adult mosquito control and are they safe?

  Treatment details will be posted on our website. All products used are approved by the EPA for adult mosquito control.

  The EPA has determined that adulticides can be used for public health mosquito control programs without posing risks of concern to the general population or to the environment when applied according to the pesticide label.

  United States Environmental Protection Agency - Information on Adult Mosquito Control

• How will these products be applied?

  Adulticides are applied as ULV fine mists into the air that kill adult mosquitoes upon contact and then rapidly disappear (within minutes).  Depending on the situation, these adulticides may be applied with hand-held, backpack, portable, and/or truck-mounted equipment by skilled vector control technicians certified by the California Department of Public Health. 

• Can people experience health effects from an adult mosquito control application?

  The EPA has evaluated these products and determined that use of these products do not pose a risk to people when used in accordance with their labels. If you are concerned about having enhanced sensitivity to these products, please contact your health care provider for recommendations.

  United States Environmental Protection Agency - Information on Adult Mosquito Control

• What kinds of precautions should I take when adult mosquito control is scheduled for my street?

  You can reduce your exposure to the adulticide by staying indoors and closing windows during the spraying or not being in the area when they are applied. When applied as an ultra-low volume spray, the droplets will dissipate after about 30 minutes and afterward, you may resume normal activities.

  Other things that you can do to reduce exposure are:

  • Keep windows closed. 
  • Turn off any fans that draw air in from the outside. When using air conditioners, set them for re-circulating indoor air. Most window and wall air conditioning units running on cooling settings do not draw air from outside of the home, so these can be left on.
  • Keep pets indoors during spraying. Wash any pet food and water bowls that were left outside during the treatment.
  • Cover your fishponds.
  • Clean homegrown fruits and vegetables with water as you would typically do before cooking or eating them – no other precautions are necessary.
  • If skin and/or clothes or other items are exposed to the insecticide, wash with soap and water.
  • Wait at least 30 minutes after the treatment before going outside into the area treated.  
  • Wipe down or cover outdoor items such as toys and barbecue grills.
  • Beekeepers and those with insects kept outdoors are encouraged to shelter hives and habitats during treatments.
• Can adult mosquito control harm other animals or wildlife?

  The EPA has determined that when used in accordance with the label, ULV adulticide sprays are not harmful to pets and do not pose an unreasonable risk to birds or other mammals. However, they can be toxic to fish, bees, and other insects; therefore, County technicians are highly trained and take precautions so that the adulticides do not harm fish, bees, and other insects. You can assist by covering any fishponds on your property during the spray event.  

• Should I cover the swimming pool in my yard?

  It is not necessary to do so. ULV insecticides break down quickly in sunlight, so no special precautions are needed for outdoor swimming pools. 

• Will an adulticide spray hurt the paint on my car?

  No. Mosquito insecticides are applied as ULV sprays, which will not affect the paint on your car. 

• Will this treatment affect bees?

  ULV insecticide applications performed at night will not affect bees since they aren’t out during the night. If a daytime application is necessary, applicators are trained to watch for bees in the area, to avoid blooming plants, when possible, and to avoid beehives and other areas where bees may congregate. 

  We recommend registering your apiary with the County of San Diego Department of Agriculture, Weights, and Measures. Registered beekeepers can request to be notified prior to  adulticide applications within one mile of their apiary when the adulticide product label indicates it is “toxic to bees.” Hives can be protected by draping a wet burlap cloth over the hive while leaving an opening in the front for bees to enter and exit.

• Are there other steps I can take to protect myself and my family against mosquito transmitted diseases?

  Yes, dump out or remove any standing water around your home. Mosquitoes can breed in practically any standing water around your home (indoors and outdoors) that is ¼ inch deep or deeper. Check for and empty out containers holding water weekly. Visit our prevention page for more tips. Also, protect yourself against mosquitoes by making sure screens on windows and doors are in good condition, applying EPA-registered insect repellents containing DEET, oil of lemon eucalyptus, picaridin, or IR3535, and wearing long sleeves and pants.

• Who can I contact if I have more questions?

  For more information about mosquitoes, diseases they transmit, or adult mosquito control please visit our website at SDVector.com. You may also call the County of San Diego Vector Control Program at (858) 694-2888 or email us at: vector@sdcounty.ca.gov.