Mosquito Spraying FAQs

What Fogging Does:

• Kills flying mosquitoes: When the fogging happens, it targets and kills the mosquitoes that are currently flying in the treated area.
• Temporary reduction: The mosquito population in your area will likely decrease for a few days after fogging.
• Doesn't eliminate all mosquitoes: Fogging doesn't kill mosquito eggs or larvae, and new mosquitoes can still enter the area from elsewhere.

Is it Safe?

The U.S. Environmental Protection Agency (EPA) carefully reviews and approves the insecticides used in mosquito fogging to ensure they are applied safely and with minimal risk to people and the environment when used correctly.

• Low risk: Studies by the EPA have shown that the levels of insecticide people are typically exposed to during fogging are far below what might cause health concerns.
• Not risk-free: While the risks are low, no pesticide is entirely without risk. Your individual risk depends on how much contact you have with the insecticide and for how long. Factors like age, health, and lifestyle can also play a role.

How to Minimize Exposure (Common Sense Steps):

• Stay informed: Watch for announcements about fogging in your local news and remain indoors when it's happening in your neighborhood.
• Protect yourself indoors: Close windows and doors and turn off your air conditioning or set it to recirculate indoor air during fogging.
• Keep kids safe: Don't let children play near the fogging trucks. Keep them inside during fogging and for about an hour afterward to ensure the fog has dissipated.
• Protect pets and fish: Bring pets indoors and cover outdoor fish ponds.
• Seek medical advice if concerned: If you think you're experiencing health issues from the fogging, contact your doctor.
• Chemical sensitivities: If you have chemical sensitivities or a pre-existing health condition that could be aggravated, consult your doctor or local health department for advice on taking extra precautions.

Impact on Wildlife:

The EPA also considers the effects of these insecticides on wildlife. When applied according to the label, the fogging should mainly affect insects similar in size to mosquitoes and should not harm other wildlife. If you have concerns after spraying, contact the South Dakota Department of Agriculture (SDDA).

Remember: Even with fogging, it's important to continue using personal protection methods against mosquitoes.

Mosquito control agencies use truck-mounted fogging units to apply insecticides as an ultra-low-volume (ULV) spray. ULV spray units dispense very fine aerosol droplets (fog) that stay aloft and kill mosquitoes on contact.  The amount of insecticide sprayed by ULV units is small compared to the area treated, usually about 3 to 5 ounces per acre, which minimizes exposure and risks to people and the environment. Some communities have thermal foggers that use an oil carrier that is heated to disperse the pesticide in a dense smoke-like fog.

Mosquito fogging offers a temporary reduction in flying mosquitoes within the treated area. It does not eliminate the entire mosquito population or prevent their return. Therefore, personal protection remains essential. This includes avoiding peak mosquito biting times and locations, wearing light-colored, tightly woven protective clothing, ensuring screens are intact, using mosquito netting when needed, and applying insect repellent containing DEET (10-25% is usually sufficient, and consult a doctor for use on young children).

The best time to kill adult mosquitoes by fogging is at dusk, when they are most active and looking for food (mosquitoes feed on human or animal blood). The aerosol fog primarily targets flying mosquitoes, which is why the timing of the spray is critical.

• If you suspect that you are reacting to an insecticide, call your physician or local poison control center.
• Additional information about the active ingredients in insecticides may be obtained from the National Pesticide Information Center (NPIC) at 1-800-858-7378 from 8:30 a.m. to 6:30 p.m. (Central time) seven days a week, excluding holidays; or visit NPIC's Web site.

The amount of insecticide used to fog for adult mosquitoes is much smaller than that used to spray fruit and vegetable insect pests. However, it is always a good idea to wash fruits and vegetables before eating them to remove soil and other contaminants.

Yes, all individuals who use insecticides to control mosquitoes are required to be licensed by SDDA. There are two exceptions: homeowners who fog for mosquitoes on their own residential property and individuals who use certain insecticides to treat tires for mosquitoes at tire shops, tire recycling sites and similar businesses. For information about mosquito control licensing, call SDDA at 1-605-367-5439.

Standing water that lasts over 10 days can breed mosquitoes. If you need to treat these areas, use only mosquito-specific water treatments like "BTI" (often found as Mosquito Dunks®), and always follow the product instructions. Yard fogging for adult mosquitoes offers only temporary relief. If the product allows, spraying areas where mosquitoes rest (like dense plants) might last a bit longer, but mosquitoes will eventually return. Always use insecticides labeled for their specific purpose and follow the label directions carefully.