Mosquito Control
The Florida Department of Agriculture and Consumer Services (FDACs) maintains a registry of beekeepers in the State of Florida. It is Florida State Law (Florida Statutes, Chapter 586) that all beekeepers, whether agricultural or residential, register their apiaries with the State (see links below). It is recommended that registered beekeepers contact their local Mosquito Control ((850-651-7394 or 850-689-5774) to discuss Mosquito Control operations that may affect their apiaries. Based on the information provided, beekeepers can then initiate preventative measures to reduce the risk of impacts from mosquito treatment.
Florida’s apiaries are under siege from pests and diseases. The parasitic varroa mite, small hive beetle, and Africanized honey bee are just a few of the pests endangering honey bee populations in Florida. Unregistered apiaries can be a source of these pests which can spread to other apiaries. Registered apiaries will receive periodic State inspections to assess the health of a beekeeper’s apiaries and receive guidance in the maintenance of a healthy hive. Inspectors can also assist in removing threats from an unhealthy apiary.
Beekeeper Links
In Florida, the name yellow fly is commonly used to describe a group of about a dozen different yellow-bodied biting flies in the Tabanidae family. However, Florida tabanid experts recognize only one species, Diachlorus ferrugatus (Fabricius), as the true yellow fly. In Belize this species is known as the doctor fly.
Figure 1. Adult yellow fly, Diachlorus ferrugatus (Fabricius). Photograph by J.L. Castner, University of Florida.
The yellow fly is a fierce biter. Like mosquitoes, it is the female fly that is responsible for inflicting a bite. The males are mainly pollen and nectar feeders. Tabanids are most likely encountered in hot summer and early fall weather. They are active during daylight hours.
Adults: The adult is a predominantly yellow fly about 1 cm (3/8 inch) long, similar in appearance to a deer fly (Chrysops). The fore legs are predominantly black, the other pairs yellow. The wings are clear, with black stigma, yellow costal cell, and a prominent brown patch at the apex. The eyes of the live fly are brilliant blue-green, with two purple bands. The female can be distinguished from deer flies by the very narrow frons (space between the eyes in front), and (in both sexes) the brown wing patch at the apex, rather than across the middle, of the wing. The abdomen is yellow, black- haired on the sides, but with a broad yellow-haired stripe down the middle.
Mosquito repellents are moderately effective against adults except when the flies are very abundant or very hungry. Gloves and head nets offer the only sure means of protection. Deet (diethyl toluamide) is the most effective repellent. To prevent the possible development of dangerous hypersensitivity and systemic reactions, persons sensitive to the bites should avoid exposure to the flies.
Traps are sometimes effective in control of small areas such as yards, camping sites, and swimming pools. Trapping of nuisance flies has reduced their numbers on the Atlantic Coast of the United States. Traps have been effective when used around cattle that are confined to manageable areas.
Vegetation management can also be used to get rid of yellow flies. Yellow do not like sunny open areas. Removing shrubs or small trees around your house can increase the light levels around the house thereby making the place less favorable for yellow flies.
Adult females usually live about a week or two, while adult males live only long enough to mate, about two to four days. Only female mosquitoes bite. They need the protein in blood to produce eggs.
A female can produce as many as 250 eggs from one bloodmeal. After the eggs are laid, they may hatch in a couple of days or it may be months before they hatch.
The larva, or wriggler, emerges from the egg and grows from 1/16" to 1/4" in length in four to ten days, depending on the temperature of the water it grows in.
The next stage is the pupa, or tumbler. This stage lasts only about two days. During this time the mosquito transforms from the aquatic larva into the flying adult. The pupa does not feed.
Mosquitoes require water to breed. Adult mosquitoes lay eggs in stagnant or slow-moving water, or on moist soil or leaf litter in areas likely to collect water. By eliminating these water sources, individuals can keep new generations of mosquitoes from taking up residence in your yard. The preventative measures recommended below can have a significant impact in reducing the mosquito population on a property. Even after all of these measures are enacted, the fact is that mosquitoes fly.
The cooperative effort between residents is needed to make an even greater impact. The Okaloosa MC District encourages communication between residents in a neighborhood. However, some residents may be unwilling or unable to participate. The Okaloosa MC District will assist in the matter by request.
PREPARE YOUR HOME
1. Drill holes in the bottom of any garbage or recycling containers stored outdoors. Holes on the sides still allow enough water to accumulate in the bottom for mosquitoes to breed.
2. Keep gutters clean and unclogged. Be sure downspouts drain properly, without leaving puddles in the drainage area. It may be necessary to reroute downspouts or add extensions to carry water away.
3. Keep swimming pools clean and chlorinated, even when not in use. Homeowners who go on vacation without chlorinating their pools may return to a mosquito hatchery.
4. Walk the property after rain and look for areas in the landscape that are not draining well. If you find puddles that remain for four or more days, regrade the area.
5. Ornamental ponds should be aerated to keep water moving and discourage mosquitoes from laying eggs. Alternatively, the pond can be stocked with mosquito-eating fish called gambusia. The Okaloosa MC District maintains gambusia hatcheries across the County and may provide you with a starter stock depending on demand.
6. Dump anything that holds water twice per week if it has rained. Birdbaths, non-chlorinated wading pools, footbaths, garbage can lids and pottery will all attract breeding mosquitoes. Remember to empty the saucers under your flower pots, and don't leave water in pet bowls for more than two days.
7. Keep your property clean of items that can hold water, including discarded aluminum cans and tires.
8. Adult mosquitoes rest during the day, usually on tall weeds or other vegetation. Make the yard less hospitable to mosquitoes by mowing regularly, and keep weeds away from the home foundation.
REPELLENTS AND BARRIERS
Even when following all the precautions above to eliminate mosquito habitat, some mosquitoes will still be around. Limit exposure to the mosquitoes that remain by using effective repellents and barriers.
1. Window and door screens should be 16-18 mesh and fit snugly, without gaps around the edges. Check screens for holes and repair or replace them as needed.
2. Replace outdoor lights with yellow "bug" lights. These lights do not repel insects, but mosquitoes and other pests are less likely to find them attractive.
3. When outdoors, apply a DEET-based insect repellent according to the directions on the label. DEET will need to be reapplied as recommended on the container label.
4. Treat clothing, sunshades, and screen houses with a permethrin-based product. Permethrin repels both mosquitoes and ticks, and will last through several washes on your clothing. Read packaging labels carefully before application.
5. Some insecticides available commercially may be used by the homeowner for mosquito control. Check the labels for EPA-approved products registered as effective against adult and larval mosquitoes. A light spray application around building foundations, shrubs, and grasses will keep adults from resting in these areas.
6. Use of some other repellent products, such as citronella candles and mosquito coils, may also be effective if used in windless conditions.
MYTHS
Despite what your friends tell you, some popular mosquito control methods have no significant impact on keeping mosquitoes in check. According to Wayne J. Crans, Associate Research Professor in Entomology at Rutgers University, these often-touted mosquito solutions are not worth your time or money.
1. Bug zappers--Though the satisfying sizzle you hear from this modern day insect torture device will convince you it's working, don't expect much relief from backyard mosquitoes. According to Crans, biting insects (including mosquitoes) generally make up less than 1% of the bugs zapped in these popular devices. Many beneficial insects, on the other hand, do get electrocuted.
2. Citrosa plants--While citronella oil does have proven mosquito-repellent properties, the genetically-modified plants sold for this purpose do not. In tests by researchers, the test subjects bitten as often while surrounded by the Citrosa plants as without them. In fact, mosquitoes were observed landing on the leaves of Citrosa plants during the study.
3. Bats and/or purple martins--While both bats and the colonial purple martins will consume mosquitoes, the offending insects make up a small percentage of their natural diet. Assertions about these insectivores being effective mosquito controls grew out of misrepresented and misinterpreted data from unrelated studies. While providing habitat for bats and purple martins has its value, don't do it if your only objective is to reduce the mosquito population.
4. Electronic devices that transmit sounds to mimic male mosquitoes or dragonflies do not work. Mr. Crans goes so far as to suggest "the claims made by distributors border on fraud."
MOSQUITO CONTROL WEBSITES
- American Mosquito Control Association
- Florida Mosquito Control Association
- Mosquitoes and Ticks
- West Nile Virus
- Mosquito Control and Beekeepers
PESTICIDE INFORMATION SITES
HEALTH CENTER WEBSITES
Click on any topic / question below to view the answer.
Q: Do you have a set schedule for spraying mosquitoes?
Q: How many phone calls do you need to spray my area?
Q: How long do mosquitoes live?
Q: Do you spray for no-see-ums?
Q: Can mosquito control spray for a special event?
Q: Are mosquitoes attracted to some people more than others?
Q: Why do mosquitoes bite some people more than others?
Q: Why do mosquitoes leave welts on the skin when they bite?
Q: Are aerial mosquito control treatments harmful to people or pets?
Q: Can Listerine ward off mosquitoes?
Q: What is dog heartworm and do only dogs get it?
Q: How long will my repellent last?
Q: Who oversees pesticide applications?
Q: Why can’t I see the spray coming out of the truck or plane like before?
Q: What methods are used to control mosquitoes?
Q: Is that tons of mosquitoes clinging to house?
Q: What beneficial purpose do mosquitoes serve?
Q: Will LCMCD use genetically modified mosquitoes?
Q: Do you have a set schedule for spraying mosquitoes?
Spraying for adult mosquito outbreaks occurs only on an as needed basis and only if mosquito populations meet State guidelines for treatment. Okaloosa County Mosquito Control District conducts several on-going types of surveillance to quantify mosquito populations. That being said, Historical data indicates that at some point in the spring and fall, surveillance data meets the minimum requirements each week so treatment is expected.
Q: How many phone calls do you need to spray my area?
The number of phone calls for service does not determine when or where treatment for adult mosquitoes will be done. Spraying for adult mosquito outbreaks occur only on an as needed basis and only if mosquito populations meet State guidelines for treatment. Okaloosa County Mosquito Control District conducts several on-going types of surveillance to quantify mosquito populations. Generally, staff will know where mosquito populations have increased, but occasionally, phone calls are important because they alert the District of potential problem areas that surveillance has not predicted. It could also indicate an individual is experiencing a problem confined to their property or neighborhood. In such situations, an inspector will be dispatched to determine if treatment is justified.
Q: How long do mosquitoes live?
Mosquitoes are relatively fragile insects with an adult life span that typically lasts 3-6 weeks. The vast majority meets a violent end by serving as food for birds, dragonflies, and spiders; or is killed by the effects of wind, rain, or drought. Some mosquito species may persist in for as long as 5 months if environmental conditions are favorable.
Q: Do you spray for no-see-ums?
Okaloosa County Mosquito Control was created to prevent health and nuisance problems caused by mosquitoes. Effects of treatment on adult no-see-um populations are collateral damage, but treatments can only be made if surveillance indicates the need to treat for mosquitoes not based on midge populations. For more information on no-see-ums, which are Culicoides or also known as biting midges, go to:
Okaloosa County Mosquito Control was created to prevent health and nuisance problems caused by mosquitoes. Treatments to control adult mosquitoes may help alleviate Chironomidae (also known as non-biting midges) populations through collateral damage. Treatments can only be made if surveillance indicates the need to treat for mosquitoes not based on midge populations. For more information on non-biting midges to:
Okaloosa County Mosquito Control was created to prevent health and nuisance problems caused by mosquitoes. The pesticides used are labeled for treatment of mosquitoes and not for control of bees. If you want the hive exterminated, please contact a licensed pest control company.
Q: Can mosquito control spray for a special event?
It is against State regulations to spray for mosquitoes without scientific data to show treatment for adult mosquitoes is justified. If Okaloosa County Mosquito Control District is notified of the location, date, and time the event is to be held, at least 3 working days in advance of the event, various methods of surveillance can be done in that area to determine if treatment can be justified. Please call (850) 651-7394 to request treatment for a special event.
Q: Are mosquitoes attracted to some people more than others?
Yes. Mosquito attraction to humans is a very complex matter. Primarily mosquitoes are attracted to the carbon dioxide (CO2) emitted from the breath and pores of humans and other animals. Mosquitoes are attracted to lactic acid, a by-product of human metabolism found in sweat. Mosquitoes are also attracted to fragrances, body heat, moisture, dark colors, and movement. During mosquito season it is recommended that people who wish to be less attractive to mosquitoes wear unscented products and light colored clothing. Odors produced by skin microflora also play a part in inducing the mosquito to land. Over 350 compounds have been isolated from odors produced by human skin. Either singly or in combination, many of these compounds may be attractants. And, many may be repellents. Visual stimuli, such as movement, also factor into host-seeking behavior by mosquitoes. Mosquito attraction is complicated and will require many years of testing before it can be completely sorted out.
What can be safely stated, though, is that ingestion of garlic, vitamin B12 and other systemics has been proven in controlled laboratory studies to have no impact on mosquito biting. Conversely, eating bananas did not attract mosquitoes as myth suggests, but wearing perfumes does. People drinking beer have been shown to be more attractive to mosquitoes. Limburger cheese has also been found to be attractive. Scientists have theorized that this may explain the attraction some mosquitoes find for human feet.
Another way to become less attractive to mosquitoes is to wear a commercially available, proven mosquito repellent. The District follows the Center for Disease Control recommendations on repellent.
CDC evaluation of information contained in peer-reviewed scientific literature and data available from EPA has identified several EPA registered products that provide repellent activity sufficient to help people avoid the bites of mosquitoes. Products containing these active ingredients typically provide reasonably long-lasting protection:
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DEET (Chemical Name: N,N-diethyl-m-toluamide or N,N-diethly-3-methyl-benzamide)
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Picaridin (KBR 3023, Chemical Name: 2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester )
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Oil of Lemon Eucalyptus* or PMD (Chemical Name: para-Menthane-3,8-diol) the synthesized version of oil of lemon eucalyptus
IR3535 (Chemical Name: 3-[N-Butyl-N-acetyl]-aminopropionic acid, ethyl ester)
EPA characterizes the active ingredients DEET and Picaridin as “conventional repellents” and Oil of Lemon Eucalyptus, PMD, and IR3535 as “biopesticide repellents”, which are derived from natural materials.
Q: Why do mosquitoes bite some people more than others?
You come in from a summer hike covered with itchy red mosquito bites, only to have your friends innocently proclaim that they don’t have any. Or you wake up from a night of camping to find your ankles and wrists aflame with bites, while your tentmates are unscathed.
You’re not alone. An estimated 20 percent of people, it turns out, are especially delicious for mosquitoes, and get bit more often on a consistent basis. And while scientists don’t yet have a cure for the ailment, other than preventing bites with insect repellent (which, we’ve recently discovered, some mosquitoes can become immune to over time), they do have a number of ideas regarding why some of us are more prone to bites than others. Here are some of the factors that could play a role:
Blood Type
Not surprisingly since, after all, mosquitoes bite us to harvest proteins from our blood research shows that they find certain blood types more appetizing than others. One study found that in a controlled setting, mosquitoes landed on people with Type O blood nearly twice as often as those with Type A. People with Type B blood fell somewhere in the middle of this itchy spectrum. Additionally, based on other genes, about 85 percent of people secrete a chemical signal through their skin that indicates which blood type they have, while 15 percent do not, and mosquitoes are also more attracted to secretors than non-secretors regardless of which type they are.
Carbon Dioxide
One of the key ways mosquitoes locate their targets is by smelling the carbon dioxide emitted in their breath they use an organ called a maxillary palp to do this, and can detect carbon dioxide from as far as 164 feet away. As a result, people who simply exhale more of the gas over time generally, larger people, have been shown to attract more mosquitoes than others. This is one of the reasons why children get bit less often than adults, on the whole.
Exercise and Metabolism
In addition to carbon dioxide, mosquitoes find victims at closer range by smelling the lactic acid, uric acid, ammonia and other substances expelled via their sweat, and are also attracted to people with higher body temperatures. Because strenuous exercise increases the buildup of lactic acid and heat in your body, it likely makes you stand out to the insects. Meanwhile, genetic factors influence the amount of uric acid and other substances naturally emitted by each person, making some people more easily found by mosquitos than others.
Skin Bacteria
Other research has suggested that the particular types and volume of bacteria that naturally live on human skin affect our attractiveness to mosquitoes. In a 2011 study, scientists found that having large amounts of a few types of bacteria made skin more appealing to mosquitoes. Surprisingly, though, having lots of bacteria but spread among a greater diversity of different species of bacteria seemed to make skin less attractive. This also might be why mosquitoes are especially prone to biting our ankles and feet since they naturally have more robust bacteria colonies.
Beer
Just a single 12-ounce bottle of beer can make you more attractive to the insects, one study found. But even though researchers suspected this was because drinking increases the amount of ethanol excreted in sweat, or because it increases body temperature, neither of these factors were found to correlate with mosquito landings, making their affinity for drinkers something of a mystery.
Pregnancy
In several different studies, pregnant women have been found to attract roughly twice as many mosquito bites as others, likely the unfortunate confluence of two factors: They exhale about 21 percent more carbon dioxide and are, on average, about 1.26 degrees Fahrenheit warmer than others.
Clothing Color
This one might seem absurd, but mosquitoes use vision (along with scent) to locate humans, so wearing colors that stand out (black, dark blue or red) may make you easier to find, at least according to Jonathan Day, a medical entomologist at the University of Florida, in commentary he gave to NBC.
Genetics
As a whole, underlying genetic factors are estimated to account for 85 percent of the variability between people in their attractiveness to mosquitoes regardless of whether it’s expressed through blood type, metabolism, or other factors.
Natural Repellants
Some researchers have started looking at the reasons why a minority of people seem to rarely attract mosquitoes in the hopes of creating the next generation of insect repellants. Using chromatography to isolate the particular chemicals these people emit, scientists at the UK’s Rothamsted Research lab have found that these natural repellents tend to excrete a handful of substances that mosquitoes don’t seem to find appealing. Eventually, incorporating these molecules into advanced bug spray could make it possible for even a Type O, exercising, pregnant woman in a black shirt to ward off mosquitoes for good.
References:
https://en.wikipedia.org/wiki/Chromatography
http://www.wsj.com/articles/SB10001424052970204660604574378933761528214
Only female mosquitoes bite. They seek blood for egg production. It serves no nourishment function. Males do not produce eggs; therefore, they do not seek blood. In order to obtain energy, both male and female mosquitoes feed upon plant nectars – much in the same manner as honeybees.
Content Source: Common Questions Asked About Mosquito Control, Florida Mosquito Control Association and the Florida Medical Entomology Laboratory.
Q: Why do mosquitoes leave welts on the skin when they bite?
When the female mosquito pierces the skin for her “blood meal”, she injects a small amount of saliva into a capillary. The saliva makes penetration of her proboscis or mouthparts easier and prevents the blood from clotting. Welts or red itchy bumps that may appear after the bite of the mosquito are actually an allergic reaction to the saliva. Some people are more allergic to mosquito saliva than others and tend to react stronger. Some people may be more allergic to specific species of mosquitoes than other species, which is why you may react stronger to mosquitoes in one area than another. 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, even to the point where they need medical attention. In any case, people should avoid scratching these welts as bacteria from the fingernails may be introduced into the wound and cause infection.
According the Centers for Disease Control and Prevention (CDC) the answer is no. There is no evidence to support that likelihood exists. If HIV infected blood is taken by a mosquito the virus is digested or killed inside the body of the mosquito. Many studies have been conducted on this issue in the United States and abroad. There has not been a successful transfer of the virus from an infected source to another host by blood feeding insects under experimental conditions. The experts have concluded that the insects are not capable of such transmission. Many biological reasons would lead one to this same conclusion, but the extensive experimental studies are the most powerful evidence for the conclusion.
Two key factors emerged from the research. First, HIV does not replicate in mosquitoes; thus, mosquitoes cannot be a biological vector as they are for malaria, yellow fever, or dengue. In fact, mosquitoes digest the virus that causes AIDS. Second, there is little possibility of mechanical transmission (i.e., flying contaminated syringes); even though we know that HIV can be transmitted by dirty needles. The amount of “blood” on a mosquito’s mouth part is tiny compared to what is found on a “dirty” needle, making the risk from mosquito bites proportionally smaller than needle transmission. Calculations based on the mechanical transmission of anthrax and Rift Valley fever virus, both of which produce very high titers in blood unlike HIV, showed that it would take about 10,000,000 mosquitoes that first fed on a person with AIDS and then continued feeding on a susceptible person to get 1 transmission.
Q: Are aerial mosquito control treatments harmful to people or pets?
After the USEPA determine an insecticide can be registered for use in the United States, the Florida Department of Agriculture & Consumer Services (FDACS) determine which pesticides can be registered and applied in the State of Florida. The primary aerial adulticide material used by Okaloosa County Mosquito Control District is Permethrin. FDACS states “Permethrin, sold under the name Kontrol 4,4… when applied in accordance with the label, can be used to kill mosquitoes without posing unreasonable risks to human health or the environment”.
Q: Can Listerine ward off mosquitoes?
The primary ingredient in Listerine is eucalyptol, a natural oil that is also an active ingredient in botanical repellents. Several studies, including one from the London School of Hygiene and Tropical Medicine, have found that eucalyptus based repellents can be extremely effective and nontoxic to humans. However, the eucalyptus-based repellents contained 75% concentration of the compound and the concentration found in Listerine and other mouthwash is usually below 1%. Listerine is actually .092% eucalyptol. Mouthwashes are usually water and alcohol based which causes them to evaporate quickly. Commercial repellents such as DEET, Picaridin and oil of lemon eucalyptus are formulated to last for hours. While Listerine may ward off mosquitoes momentarily, it will not work as a barrier treatment to prevent mosquitoes around the house and it will not provide protection applied on your skin for very long.
Q: What is dog heartworm and do only dogs get it?
Dog heartworm is a very common disease of canines and to a lesser extent cats caused by a parasitic worm (Dirofilaria immitis) that can be debilitating, even fatal. Dog heartworm is transmitted to dogs by the bite of an infected mosquito. Adults live in the dog’s heart and release microscopic young worms into the dog’s blood. This infection is often fatal to the dog. Cats are also susceptible to infection by dog heartworm, although to a much lesser degree than are dogs. Human infections are sometimes discovered, usually during lung X-rays. Pet owners should talk to their veterinarians about protective medication to avoid dog heartworm. Additional information and Content source:
Q: How long will my repellent last?
According to the Center for Disease Control,
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A product containing 23.8% DEET provides an average of 5 hours of protection from mosquito bites.
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A product containing 20% DEET provides almost 4 hours of protection from mosquito bites.
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A product with 6.65% DEET provides almost 2 hours of protection from mosquito bites.
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A product with 4.75% DEET provides roughly 1 and a half hour of protection from mosquito bites.
These examples represent results from only one study and are only included to provide a general idea of how such products may work. Actual protection will vary widely based on conditions such as temperature, perspiration, and water exposure.
Choose a repellent that provides protection for the amount of time that you will be outdoors. A product with a higher percentage of active ingredient is a good choice if you will be outdoors for several hours while a product with a lower concentration can be used if time outdoors will be limited. Simply re-apply repellent, following label instructions, if you are outdoors for a longer time than expected or start to be bitten by mosquitoes.
Q: Who oversees pesticide applications?
Florida mosquito control programs are established and operated according to the procedures given in the Mosquito Control Law, Chapter 388 Florida Statute (F.S.) and the Mosquito Control Rules, Chapter 5E-13, Florida Administrative Code (F.A.C.). The Federal Insecticide, Fungicide and Rodenticide Act of 1972 (FIFRA) requires that the Environmental Protection Agency (EPA) be certain that all personnel handling hazardous or restricted use chemicals be trained to do so correctly and safely and that they be certified as pesticide applicators.
The state agency administering the certification is appointed by the governor of each state. In Florida, the Department of Agriculture and Consumer Services (DACS) is the lead agency. They require that every employee applying pesticides for public control of mosquitoes be certified or be supervised by a certified applicator.
Q: Why can’t I see the spray coming out of the truck or plane like before?
The spray you used to see during adult mosquito treatments was produced by diluting a pesticide with diesel or fog oil in a technique called thermal fogging. The mixture was heated producing a cloud of smoke. The oil acted as a carrier to help disperse the pesticide in the proper concentrations and helped pilots see where they had treated. Newer methods of spraying called ultra-low volume or ULV have almost eliminated the need for the thermal applications and therefore no fog is seen during spray treatments. Pilots now rely on global positioning system (GPS) to determine treatment paths. This newer method still provides effective control of mosquitoes, eliminates the adverse health and environmental effects of the oil, and is much more efficient. One DC-3 can now provide the same area of treatment for adult mosquitoes in one night that it would have taken 6 DC-3s using the thermal fog applications.
Q: What methods are used to control mosquitoes?
There are four basic approaches to controlling mosquitoes: prevention, source reduction, larviciding and adulticiding. Preventing mosquitoes from breeding is the most desirable solution. Unfortunately, many human modifications of the environment such as ditches, retention ponds, and water management structures create mosquito breeding sites. Prevention requires working with planners to plan, construct, and maintain infrastructure without producing mosquito breeding habitats.
Source reduction is the elimination of water in which mosquitoes lay their eggs and in which the larvae develop or by containing water to eliminate areas for mosquitoes to lay their eggs. Source reduction is the second most effective method for controlling mosquitoes. Methods of source reduction involve eliminating containers that hold water and filling wet areas with soil.
Larviciding is the use of materials to control immature stages of mosquitoes or prevent development of larvae from becoming adult mosquitoes. Larvicides are applied to waters that contain larvae and or pupae. Larvicides are effective in low concentrations and generally do not impact other organisms in the water or habitat. Every acre that is treated to prevent adult mosquitoes from emerging reduces the number of acres that must be treated with spray trucks or aircraft. Okaloosa County Mosquito Control has built a program focusing on larviciding to control mosquitoes.
Adulticiding is the last effort to control mosquitoes. Applied as directed, adulticide treatments have minimal effects on other insects. Okaloosa County Mosquito Control is diligent in ensuring the proper size droplets and application rates are used. Adulticiding is typically done at night and at dusk and dawn when adult mosquitoes are most active, which is also when most non-target insects like bees, dragonflies and butterflies are not as active.
Q: Is that tons of mosquitoes clinging to house?
Probably not. Male mosquitoes swarm during mating and some will rest on the side of a house together. Both male and female mosquitoes will seek shade during hot weather and, if a house offers a cool, shady resting spot, then mosquitoes may cling to the walls. However, usually large swarms of insects clinging to a house or side of buildings are non-biting midges. These look very much like mosquitoes, but do not bite. They are often called “blind” mosquitoes. If midges are clinging to your house it is a good idea to wash them down with a hose to prevent them from staining your wall.
Q: What beneficial purpose do mosquitoes serve?
All species of plants and animals have their place in nature. Mosquitoes are no exception. Although no species depend solely on mosquitoes as a food source, indiscriminate predators will eat mosquito larvae and or adults if other food sources are not readily available; therefore, mosquitoes are part of a link in the food chain. During their aquatic stage, mosquito larvae provide food for other aquatic insects such as dragonfly nymphs, beetles, fish, and other creatures. Mosquito control treats larvae that are in areas not generally controlled by natural predators. By treating the areas that are not being controlled by natural predators, mosquitoes remain part of the overall food chain. As adults both male and female mosquitoes need liquid nourishment for food. Mosquitoes may serve as an incidental pollinators as they collect nectar for nourishment.
Q: What is larviciding?
Larviciding is controlling mosquitoes in their larval stage. Control of larval mosquitoes is the backbone of Okaloosa County Mosquito Control District’s program. Larvicides are products used to reduce immature mosquito populations. They can be either biological or chemical products. Larvicides are applied directly to water sources that hold mosquito eggs and larvae. When used as an integral component of a management scheme, larviciding can help to reduce the overall mosquito population by limiting the number of new mosquitoes that are produced.
Adulticiding is controlling mosquitoes in their adult stage. Adulticides are products that rapidly reduce adult mosquito populations. This can become necessary when larval control measures are insufficient or not feasible. Adulticiding may be initiated when there is evidence of significant populations of mosquitoes in a region or if there is evidence of mosquito borne disease in Okaloosa County. The most common method of adulticiding is ultra-low volume (ULV) spraying. ULV spraying is the process of putting very small amounts of liquid into the air as a fine mist of droplets. These droplets float on the air currents and quickly eliminate mosquitoes that come into contact with them. ULV adulticides are applied when mosquitoes are most active-typically early evening or pre-dawn. Adulticides can be applied from hand-held sprayers, truck-mounted sprayers, helicopters or airplanes.
Q: Will LCMCD use genetically modified mosquitoes?
While genetically modified mosquitoes (GMM) may be appropriate for some situations, it is not a likely option for Okaloosa County at this time. There are factors which would make this control tool unsatisfactory for Okaloosa County. To understand why genetically modified mosquitoes would work in some situations, but not in others requires some basic understanding on the method and what species of mosquito is being targeted for control.
Utilizing sterile insects as a control technique is not new technology. To use sterile insects for control purposes: the insects must be able to be mass produced in a laboratory, insects are then sterilized or altered to have a lethal gene not harmful to the carrier insect, the insects must be able to compete with the wild population for mating, the number of sterile insects released must be sufficient to overwhelm the native insect population, and there must be a barrier or buffer that minimizes the movement of insects from outside the sterilization zone.
A successful example of utilizing sterile insects to control a harmful insect is the screwworm fly eradication in the southeast United States by the United States Department of Agriculture (USDA). The USDA began the program in Florida in 1958. A laboratory/factory in Sebring began rearing 75 million sterile screwworm flies per week. They released 75 to 300 sterile screwworm flies per square kilometer by airplanes. The flies were pushed out of the United States and a buffer area in Central America was created where sterile screwworm flies are continually released to prevent re-entry into the United States. The program has been successful and the last infestation in Florida was in 1959 and the last reported case in the United States was in 1982.
Researchers have been seeking to find a way to use sterile insect techniques in the control of mosquitoes. The company Oxitech has been a leader in this research. One of the benefits of using a sterile insect technique is that it focuses on the specific species to be controlled. Oxitech is working with the mosquito species Aedes aegypti, which is the vector of Zika, Yellow Fever, Dengue, Chikungunya, and Japanese encephalitis.
Oxitech uses Aedes aegypti mosquitoes that have been genetically modified to require tetracycline in their diet in order to survive. The genetically modified male Aedes aegypti mosquitoes would be released to mate with native, female Aedes aegypti mosquitoes. The mosquitoes would produce nonviable larvae that would die due to the lack of tetracycline in their diet. Oxitech has successfully utilized genetically modified Aedes aegypti mosquitoes in the Cayman Islands, Brazil, and Malaysia and is currently working with the Florida Keys Mosquito Control District and seeking permission to test this technique in Key West.
Okaloosa County Mosquito Control District would not select this method of control at this time for several reasons. The primary concern would be while sterile males are released, adulticide treatments for other species of mosquitoes would require extra coordination to prevent killing released GMM. Aedes aegypti mosquitoes have not been trapped in Okaloosa County for over 20 years. Introducing GMM may reintroduce Aedes aegypti into the environment. Aedes albopictus is a competent mosquito vector for mosquito borne disease in its own right and there is no GMM for Aedes albopictus
Although Okaloosa County Mosquito Control District views GMM as a viable control tool, Okaloosa County Mosquito Control District is not considering the use of GMM at this time for the above mentioned reasons.
