Mosquito Operations FAQs

The best way to prevent mosquito-borne illness is to prevent mosquito bites. Hillsborough County recommends:

• Dress: Wear shoes, socks, loose-fitting long pants, and long-sleeved shirts when mosquitoes are present. Light-colored clothing can also help. 
• Defend: Use an Environmental Protection Agency-approved insect repellent containing an effective ingredient such as DEET, picaridin, IR3535, oil of lemon eucalyptus or para-menthane-diol. Always follow the instructions on the product label, especially when applying repellent to children. 
• Dump: Drain or cover standing water around your home to eliminate places where mosquitoes can breed. 
• Keep doors and windows closed and make sure window and door screens are in good repair. 

Mosquitoes need water to trigger eggs to begin the life cycle. Eliminating standing water removes places where mosquitoes can lay eggs and develop into adults. Even small amounts of water in containers around a home can become mosquito-breeding sites.

Regularly: 

• Empty water from buckets, garbage cans, gutters, pool covers, coolers, toys, flowerpots, and other containers. 
• Empty and clean birdbaths and pet water bowls at least twice a week. 
• Discard old tires, bottles, pots, broken appliances, and other items that can collect rainwater. 
• Keep swimming pools properly maintained and chlorinated. 
• Cover boats and vehicles so they do not collect rainwater. 
• Remove, cover, or turn over items that can hold rainwater. 

Some mosquitoes can carry viruses and other pathogens. A mosquito can become infected when it bites an infected person or animal. The infected mosquito can then transmit the pathogen when it bites another person. 

Hillsborough County monitors mosquito populations and mosquito-borne illness activity through mosquito traps, mosquito testing, sentinel chickens, and information from the Florida Department of Health. This surveillance helps Mosquito Management Services determine where additional mosquito control may be needed.

Hillsborough County uses an integrated mosquito management approach that includes surveillance, eliminating breeding sites, controlling mosquito larvae, and treating adult mosquitoes when necessary. 

Large-scale treatments may be conducted when surveillance indicates mosquito populations are high enough to threaten public health, mosquito-borne disease has been detected in an area, or mosquito populations have reached nuisance levels.

Dengue is primarily spread by infected Aedes mosquitoes, including Aedes aegypti and Aedes albopictus. These mosquitoes commonly are found around homes and tend to lay their eggs in containers that hold water, such as buckets, bowls, animal dishes, flowerpots, and similar items.

Unlike some mosquito species that are most active at night, Aedes aegypti and Aedes albopictus bite mainly during the day, with some activity at night. They prefer to live near people and can be found both indoors and outdoors. 

Because these mosquitoes can bite during daylight hours, residents should protect themselves throughout the day, not just at night.

Yes. The mosquitoes that spread dengue commonly breed in small containers that hold water around homes. Regularly dumping or draining standing water can eliminate mosquito-breeding sites before mosquitoes become adults.

Aerial treatment allows Mosquito Management Services to treat large areas efficiently, including locations that can be difficult to reach by truck or on foot. 

The County uses aircraft for both larval and adult mosquito control. The type of treatment depends on surveillance data and the stage of the mosquito being targeted.

There are two basic types of aerial mosquito treatments: 

Adulticide treatments target adult flying mosquitoes. Hillsborough County uses Dibrom, an EPA-registered insecticide, for aerial adult mosquito treatments. It is applied using ultra-low-volume (ULV) equipment that produces very small droplets designed to come in contact with adult mosquitoes in the air. 

Larvicide treatments target mosquito larvae before they become adult mosquitoes. Hillsborough County uses EPA-registered, Bti-based products for appropriate treatment areas. These treatments target immature mosquitoes in water or mosquito-breeding areas. 

Depending on the treatment, Mosquito Management Services uses helicopters equipped with specialized application equipment. 

Recent adult mosquito treatments in Hillsborough County have been conducted by helicopter at approximately 150 feet above the ground. The aircraft uses calibrated ULV equipment to apply the treatment at the appropriate rate for the area.

Adult mosquito treatments generally are conducted after sunset and completed before sunrise. This is because many mosquito species are most active during the evening and nighttime hours, and winds typically are calmer, allowing treatments to be applied more effectively. It's also the time when bees, butterflies, and people have less activity. 

Larval treatments can occur during the daytime because they target mosquitoes in their immature stage and are applied to breeding areas rather than flying adult mosquitoes. 

During periods of increased risk of mosquito-borne illness, residents may see helicopter treatments during both daytime and nighttime hours.

Hillsborough County uses EPA-registered mosquito population control products and applies them according to their labeled requirements. The mosquito population control products are applied by trained and state-licensed personnel. 

The EPA explains that mosquito adulticides are applied in ULV applications using small quantities of pesticide relative to the size of the treatment area. When used according to the pesticide label, EPA states that adulticides can be used for public health mosquito control without posing risks of concern to the general population. 

For additional exposure reduction during aerial applications of Dibrom, the EPA recommends that people stay indoors with windows closed during spraying and that young children not play outdoors for four hours following spraying. 

No evacuation is required. Residents who want to minimize exposure should stay indoors and keep windows and doors closed while spraying is occurring. 

EPA recommends that young children not play outdoors for four hours following aerial application of Dibrom. Residents who are outdoors during spraying and come into contact with the product should rinse exposed skin and eyes with water. 

Hillsborough County's mosquito population control products are used according to their EPA-approved labels. Residents can further minimize their pets' exposure by keeping pets indoors during spraying and bringing pet food and water dishes indoors. 

For aerial Dibrom applications, EPA also recommends bringing pets and pet food dishes indoors and rinsing uncovered outdoor items after spraying. 

Mosquito control products are applied at low rates specifically for mosquito management. However, because mosquito adulticides are insecticides, some nontarget insects and other organisms may be affected by exposure. 

Residents with backyard beehives should take additional precautions and monitor County treatment notifications. Hillsborough County works with beekeepers to help reduce potential impacts to honeybees and other pollinators.

Residents may notice small droplets on the outside surfaces of their vehicles following some mosquito treatments. For larvicide treatments, small droplets can be washed away with water. If the product remains on a vehicle for an extended period, additional scrubbing may be needed to remove it. 

If you have questions about a specific treatment or product, contact Hillsborough County Mosquito Management Services at (813) 635-5400.

Hillsborough County provides several ways for residents to stay informed: 

• Mosquito spray notifications can alert residents when treatment missions are confirmed. Sign up to receive notifications through HCFL Alert. 
• The Mosquito Spraying Map shows planned treatments and treatments completed within the previous 28 days. 
• The County's Mosquito Operations webpage provides current operational updates. 
• Hillsborough County also publishes information about significant mosquito treatment operations through its newsroom and other public communication channels. 

The County's mosquito spray notification system sends alerts as soon as missions are confirmed and generally aims to provide notice as early as possible. 

Because treatment decisions are based on surveillance information that can become available the same day, the County often cannot provide more than a few hours' notice. Weather conditions also can change the timing of a mission. 

Mosquito treatment decisions are based on current surveillance data, including mosquito trap results, mosquito pool testing, sentinel chicken results, and reports of suspected mosquito-borne illness from the Florida Department of Health. 

The decision to conduct a treatment may be made the same day the surveillance information becomes available. Weather conditions also can affect whether a scheduled treatment can occur. 

The County's Mosquito Spraying Map shows both planned treatments and treatments completed within the previous 28 days.

Residents can sign up for Hillsborough County's mosquito spray notification service through HCFL Alert. 

When signing up, provide your name, email address, and property location. You can also provide a cellphone number if you would like to receive text notifications. 

Notifications are sent when mosquito treatment missions are confirmed for an area they are registered for. 

HCFL Alert is Hillsborough County's official mass notification system. Residents can choose the types of County notifications they want to receive and how they want to receive them, including email and text notifications. 

Hillsborough County uses several approaches to educate residents and provide information about mosquito prevention and treatment, including:

• The County's mosquito management webpages and educational resources. 
• Current treatment information and the online Mosquito Spraying Map. 
• Mosquito spray notifications through HCFL Alert. 
• News releases about significant mosquito treatment operations. 
• Public education events and presentations. 
• Mosquitofish giveaway events. 
• Outreach to schools, neighborhood groups, homeowners associations, parks, and community events. 
• Property inspections to help residents identify potential mosquito breeding sites.