Environmental & Extension Services Department - Pest Management Division

Mosquito FAQs

Are mosquitoes attracted to some people more than others?

Yes. The attraction to humans is very complex. Basically, mosquitoes are attracted to the carbon dioxide coming from the breath and pores of humans. In addition, some mosquito species are attracted to certain fragrances and colors. If you wish to be less attractive to mosquitoes, try using products that are unscented (i.e. hair spray, deodorant, soap, etc.) and light colored clothing. You can also try wearing commercially available, proven mosquito repellents. The most common proven repellent is N,N-diethyl-meta-toluamide or DEET. Be sure to read the entire label before using.

Are mosquitoes just blood thirsty pests?

No. Mosquitoes don’t use your blood for food. They eat plant juices and flower nectar for energy. The female mosquito (the only one that bites) needs the protein found in blood to help her eggs grow and mature before she lays them.

How much blood do they take?

On the average, mosquitoes take one millionth of a gallon of blood with each bite. That means it would take 1,120,000 bites to drain all the blood from an average adult human.

Who do mosquitoes usually bite?

Mosquitoes have developed the ability to take a blood meal (bite) just about any creature with blood. That means mammals (us, cats, dogs, cows, etc.), birds, reptiles (even snakes!), and amphibians.

How many kinds of mosquitoes are there?

Here in Charlotte county, we have about 37 different types (or species) of mosquitoes. In Florida, there are 76 different species form 12 different genera, approximately 30 of which occur throughout the entire state. In North America, there are about 1,200 different types. There are over 3,000 species of mosquitoes worldwide. Each type of mosquito has a common name and a scientific name. An example of this would be the gallinipper, also known as Psorophora ciliata.

What purposes do mosquitoes serve?

Mosquitoes play an important role in the ecosystem. During their aquatic phase, mosquitoes provide food for other aquatic insects such as dragonfly and damselfly nymphs, beetles, and water scorpions, fish, bacteria, fungus, frogs, and other water-dwelling animals. As adults, they provide food for bats, birds, other insects, lizards, and spiders. They also provide work for pesticide manufacturers, health specialists, mosquito control personnel, and entomologists. When mosquitoes feed on plant juices and flower nectar for energy, they perform the important service of pollinator to these plants.

How long do adult mosquitoes live?

The life span of a mosquito varies widely from species to species. Male mosquitoes typically live for only about 2 weeks. On the other hand, the female may survive for 6 weeks to about 5 months, depending on the species and the time of year.

Why do mosquito bites itch and leave a welt?

When the female mosquito bites, she injects a small amount of saliva into your capillary, the small blood vessel from which she takes her blood meal. This saliva makes the penetration of her proboscis (mouthparts) easier and prevents the blood from quickly clotting. The welt or red bump that appears after the bite are actually a mild allergic reaction to the saliva. Some people are more allergic to mosquito saliva than others and tend to get larger welts. Some people may be more allergic to one type of mosquito than other types. The swelling and itching may last from a few hours to a few days. Occasionally, individuals may be highly sensitive to mosquito saliva and swell significantly. In any case, you should avoid scratching these welts to prevent the introduction of bacteria causing an infection.

What diseases do mosquitoes carry?

Mosquitoes kill more than one million people each year with the deadly diseases they transmit. These diseases include malaria, filariasis, dengue fever, yellow fever, and encephalitis (mainly the St. Louis and Eastern Equine strains). They can also transmit heartworm to dogs and cats. However, not all mosquitoes carry diseases. Each disease is transmitted by only a few species of mosquito. Here in Florida and Charlotte county, we mainly focus on St. Louis Encephalitis (SLE) and to a lesser extent, Eastern Equine Encephalitis (EEE). We have not yet seen the West Nile Virus in Florida, but our Department is cooperating with the Florida Department of Health in monitoring for any activity.

What about AIDS? Do mosquitoes transmit that?

Mosquitoes ABSOLUTELY DO NOT transmit the HIV virus that causes AIDS. If HIV infected blood is taken in by the mosquito, the virus is digested and quickly dies in the mosquito’s stomach. Because it cannot survive in the mosquito’s stomach, it cannot replicate and migrate to the salivary glands for further transmission (the path all mosquito-borne diseases must take to be transmitted).

What is St. Louis Encephalitis (SLE)?

St. Louis Encephalitis, or SLE, is a mosquito-transmitted viral disease. It was first recognized in St. Louis, Missouri, in 1933. Symptoms of SLE are similar to other viral infections and may include high fever, nausea, severe headaches, and tiredness. The severity of the symptoms vary from person to person. They can range from no symptoms to mild flu-like symptoms to severe flu-like symptoms and even death. Only 1 in 200 people who become infected with the SLE virus will develop the disease. The likelihood of developing SLE symptoms is generally higher for older people.

How can a person get SLE?

You can only get SLE from the bite of any infected mosquito. It is not transmitted from person to person or animal to person. Only a few species of mosquitoes in a given area are capable of transmitting SLE. Mosquitoes pick up the virus from the blood of wild birds that are carrying the disease. The birds themselves are not sick. The virus incubates and multiplies in the mosquito’s body and eventually migrates to the mosquito’s salivary glands. This process takes about two weeks. In Florida and Charlotte county, the mosquito that is most often responsible for SLE transmission is Culex nigripalpus, a fresh and stagnant water breeder.

Are the chemicals that Mosquito Control sprays harmful to people or pets?

The amounts of Mosquito Control chemicals that are sprayed out of the trucks and aircraft are not harmful to people or pets. However, as with any chemical, it is a good idea to keep exposure to a minimum. If you or your pet accidentally gets hit with the spray, you might feel a momentary slight burning or stinging sensation on the skin or in the eyes and may cough briefly if the spray is inhaled. The smell is usually worse than the taste or sting. Unless you are very sensitive or allergic to chemicals, washing your skin with water is all that is needed. At the low insecticide dosage used, no other symptoms should be experienced. If other symptoms are experienced, a physician should be notified immediately.

How soon after spraying can children go outside?

The pesticides used for mosquito control are all registered at the federal and state levels for use around commercial, agricultural, and residential areas. These aerosol sprays are almost invisible because of their extremely small size. Because these spray droplets are very small, they float in the air and therefore, usually float around objects and people. Spray equipment is designed to scatter the spray material from the spray truck. Therefore, children can safely go outside immediately after spraying as long as they remain a distance of 25 feet from the spray truck.

What mosquito repellent works the best?

The most effective repellents are those which contain N,N-diethyl-meta-toluamide or DEET. DEET has been sold in the U.S. since 1956 and is used by 50-100 million people each year. It repels mosquitoes, no-see-ums, fleas, ticks, gnats, horse flies, deer flies, yellow flies, and chiggers. Repellents with DEET are available as pump sprays, aerosols, lotions, creams, soaps, and sticks. Be sure to read the label carefully. Repellents with 30-40% DEET work twice as well as repellents with 75% DEET. It is always best to use the lowest concentration that is effective for you. Other products that do not contain DEET as the active ingredient have limited success that vary from person to person. Do not apply DEET to your pets because it can make them sick when they lick it off of their fur.

What about bug zappers? How effective are they?

Regardless of the brand name or type of light, bug zappers do not reduce the number of mosquito bites you will get. Studies have shown that although mosquitoes are killed by the devices, their lights attract more mosquitoes into the area than would be there without the devices, just like a porch light. They also kill beneficial insects such as dragonflies that eat mosquitoes. If you already own a bug zapper and want to use it just to get the satisfaction of hearing the “zap”, then place it where it will attract mosquitoes away from the area you want to protect.

Is the mosquito spray dangerous to butterflies? Do they kill good insects and birds?

Depending on the type of chemical used, the spray might kill some individuals in certain species of butterflies or caterpillars. However, any adverse effects on butterfly populations will most likely be very localized and temporary. When the chemical is applied as directed, adverse effects on populations of non-target animals, like mammals, birds, and fish, are actually absent or very minor. However, some insects (for example, honey bees) could be killed by mosquito sprays. Fortunately, mosquito adulticiding is normally done during the time of day when these insects are not active and less likely to be killed by spraying. When planning a mosquito spraying mission, efforts are made to avoid spraying near areas known to contain bee hives.

What criteria are used when deciding when and where to spray?

Spraying for larval mosquitoes occurs only when problem species of mosquito larvae are found in large numbers. This involves constant monitoring of mosquito larvae habitats. Heavy rainfall and exceptionally high tides can cause high increases in larval populations which will soon advance to the adult stage where they can become problems for humans. Spraying for adult mosquitoes occurs only after the targeted species of mosquito has reached a point where they have become a documented problem. In order to spray for mosquitoes, certain types of mosquitoes must be found in significant numbers.

What are the requirements for spraying adult mosquitoes?

Requirements are based on criteria provided by the state and this criteria must be documented. The criteria include the following:

  • 1) When a large population of adult mosquitoes is present, a standard surveillance method, such as landing rates or traps must document an increase or a sustained high level of mosquitoes.
  • 2) When adult mosquito populations build to levels exceeding 25 mosquitoes per trap night, or 5 mosquitoes per trap hour during dawn or dusk periods.
  • 3) When mosquito service requests have been confirmed by standard surveillance methods, i.e. traps and/or landing rates.
  • 4) Aircraft applications along beaches and bayshores only when there is a three-fold increase over the normal mosquito population levels.

How often does Mosquito Control spray for mosquitoes?

Spraying for problem adult mosquitoes occurs only on an as needed basis. The need for adult mosquito spraying can vary greatly from one year to the next due to environmental conditions, especially rainfall and tides. Only a few mosquitoes are capable of causing disease problems for people. If a species of mosquito starts increasing in number to the point where it becomes a problem for humans, mosquito control efforts begin. We conduct on-going surveillance of the mosquito population in effort to keep abreast of the situation and schedule any treatment as necessary.

How effective is the mosquito spray?

Pesticides properly applied to water kill 95% - 100% of the mosquito larvae. It is more difficult to tell how effective sprays to kill adult mosquitoes are because it is not known exactly how many mosquitoes are present before spraying. Adult sprays applied by aircraft are very effective because the spray covers a very large area. Reductions of 90% in surveillance numbers before and after treatment are common. Adult sprays applied by trucks can be just as effective where parallel roads are close together, where there is a light wind, and vegetation around houses is not thick. It is less effective if there is no wind, high humidity, too few roads, and heavy vegetation.

Does Mosquito Control spray for things other than mosquitoes?

Mosquito Control exists only to help prevent health problems caused by mosquitoes. The pesticides we use are only labeled for the treatment of mosquitoes. We are only licensed by the State of Florida for mosquito control purposes. For these reasons, Mosquito Control does not treat for ants or other pests. Consult a pest control company for treatment of these pests.

Why can’t Mosquito Control spray during the day?

The main reason we do not spray during the day is that the spray would be lifted away from the ground very quickly by the rising air currents that occur during hot Florida days. At dusk and at night, the insecticide stays near the ground, where the mosquitoes are. The second reason is that most mosquitoes are active between dusk and dawn. Daytime spraying is also not practiced to avoid killing beneficial insects, such as bees; to reduce people’s and wildlife’s exposure to the pesticide; and to eliminate the potential traffic hazard of a slow-moving vehicle during high traffic volume times.

Can Mosquito Control spray ahead of time for special events, sporting events, garden weddings, parties, etc.?

It is against State regulations to spray for mosquitoes prior to any surveillance. However, if we are notified of the date and time the event is to be held, surveillance in the area could be increased. This would determine if treatment would be required before a function began. Many events do not need spraying because the event is held during the day when most mosquitoes are less active and therefore, less annoying.

How long do the chemicals last once they have been sprayed?

The longevity of a chemical depends on the chemical used and the weather conditions at the time of application. Weather in the immediate area of the spraying affects chemical droplet dispersion and deposit and ultimately its effectiveness. In general, the chemical can be gone within 15 minutes of application or last almost 4 hours after application.

Why can’t the spray be seen coming like before?

The spray that you used to see during mosquito spraying was produced by the use of diesel oil or fog oil. This oil acted as a carrier to help disperse the pesticide in the proper concentrations. Newer methods of spraying called ultra-low volume or ULV have eliminated the need for the oil and therefore, no fog is seen during the spraying. This newer method still provides effective control of mosquitoes and eliminates the adverse health and environmental effects of the oil.

For more information
Charlotte County Environmental & Extension Services
25550 Harbor View Road, Unit 2, Port Charlotte, FL  33980
941.764.4360