Learn more about aerial treatments, why helicopters fly low, and the products being used
Hillsborough County is expanding its mosquito management efforts as mosquito traps continue to show dengue virus activity throughout the County. The County uses a combination of mosquito surveillance, breeding-site reduction, ground treatments, and aerial treatments to manage mosquito populations and reduce the risk of mosquito-borne disease.
With mosquito helicopters increasingly visible over Hillsborough County, residents may have questions about what the aircraft are doing, why they fly so low, and whether the mosquito-control products they apply are safe.
Here is what residents should know about the County's mosquito management efforts.
Why are mosquito helicopters flying during the day?
Residents may notice mosquito-control helicopters flying over neighborhoods during daylight hours. These daytime flights are different from the aerial treatments residents may typically see at night.
Daytime helicopter operations are primarily used to target mosquito larvae, which are mosquitoes that have not yet become flying, biting adults. The helicopters apply liquid larvicides to areas where mosquitoes are breeding. Larvicides target mosquitoes during their immature stage, before they become adults capable of biting and potentially spreading disease.
The product used during daytime helicopter operations is *Bacillus thuringiensis israelensis*, or BTI. BTI is a naturally occurring bacterium that targets mosquito larvae. When used appropriately, BTI is not harmful to people, pets, fish, birds, or beneficial insects.
Why do mosquito helicopters fly so low?
During a daytime operation, County pilots will fly low to effectively treat coastal areas. In many instances, the helicopters will drop to just a few feet off the ground, conducting 180-degree turns repeatedly to treat an area. The low altitude also means helicopters can be significantly louder and more noticeable than residents may be accustomed to.
Because mosquito helicopters fly so low to the ground, the operations are much safer to do during daylight. Daytime treatment also allows mosquito-management crews the ability to target breeding areas that may be difficult to reach from the ground.
What about nighttime helicopter operations?
Residents may also notice an increase in nighttime mosquito helicopter operations. The County uses adulticides when the goal is to reduce populations of adult mosquitoes that are already flying and biting.
Aerial adulticide treatments generally take place after sunset and are completed before sunrise. This timing is intentional because many mosquito species are most active during evening and nighttime hours. Winds are typically calmer during this time, allowing treatments to be applied more effectively.
For aerial adulticide treatments, Hillsborough County uses Dibrom, an EPA-registered insecticide, applied through ultra-low volume (ULV) equipment. The equipment produces extremely small droplets designed to come into contact with adult mosquitoes in the air. Performing adulticide treatments at night also reduces potential exposure to people and pollinators that are more active during the day.
Adult mosquitoes can also be treated from the ground using truck-mounted ULV equipment.
Are mosquito-control products harmful to people?
Hillsborough County uses EPA-registered mosquito-control product that are applied at carefully calibrated rates by trained and state-licensed personnel. The amount used is specifically designed for mosquito management and is applied according to product labels and regulatory requirements.
For aerial adult mosquito treatments (adulticide), the amount of ULV product applied is very small relative to the size of the treatment area. Residents may notice an odor during or after an aerial treatment. While the smell may be unpleasant or irritating, the treatment is applied at a rate intended to manage mosquitoes and does not pose a health threat to people or pets.
Eliminating mosquito breeding sites
Mosquito Management crews also conduct inspections and treat locations where mosquitoes breed. This can include standing water in natural areas, drainage systems, containers, and other locations capable of holding water.
Treating mosquitoes before they reach adulthood is an important part of reducing the number of mosquitoes capable of spreading disease.
Residents can also help reduce mosquito populations around their homes by eliminating places where mosquitoes can breed.
Protecting yourself from mosquito bites
The County recommends following the 3 Ds:
- Dress: Wear light-colored, long-sleeved clothing and closed-toed shoes.
- Defend: Use an insect repellent containing a CDC-recommended ingredient, such as DEET or Picaridin.
- Dump: Dump or cover standing water around your home. Mosquitoes that spread dengue commonly breed in small containers that hold water.
Discover answers to commonly asked questions about the pest including information about how mosquitoes spread diseases.
Hillsborough extends State of Local Emergency
Hillsborough County Administrator Bonnie Wise on Oct. 1 signed an executive order extending the state of local emergency in Hillsborough County.
The emergency declaration gives the County Administrator and emergency managers the ability to quickly take certain actions to ensure the health, safety, and the welfare of the community.
Residents are encouraged to visit the County's mosquito operations hub. There, residents can sign up to receive notifications about localized aerial treatments, report mosquito issues, and stay up to date on latest updates surrounding the dengue virus.
Mosquito control services are funded in part by Hillsborough County property tax dollars.