Public Health Pest Control Applicator Training Manual

Public Health Pest Control

APPLICATOR TRAINING MANUAL

Florida Department of Agriculture and Consumer Services

3125 Conner Boulevard

Tallahassee, Florida 32399-1650

Public Health Pest Control

APPLICATOR TRAINING MANUAL

Florida Department of Agriculture and

Consumer Services

3125 Conner Boulevard

Tallahassee, Florida 32399-1650

Acknowledgements

In accordance with Florida Administrative Code

Chapter 5E-13.040, all persons who apply or supervise

the application of a pesticide intended to control

arthropods on property other than their own individual

residential or agricultural property must be licensed to

do so with a Public Health Pest Control (PHPC) license

or work under the supervision of a licensed applicator.

In order to obtain the PHPC license, applicants must

score 70% or above on two exams administered by the

Florida Department of Agriculture and Consumer

Services (FDACS): the General Standards (Core) exam

and the Public Health Pest Control exam. This Public

Health Pest Control Manual, in conjunction with the

Core Manual “Applying Pesticides Correctly” published

by University of Florida, will provide general

information necessary to meet U. S. Environmental

Protection Agency and Florida standards for

certification as a pesticide applicator in the commercial

category, Public Health Pest Control.

The original Public Health Pest Control Manual

was prepared by Elisabeth Beck of the Florida

Department of Health and Rehabilitative Services

(HRS), Office of Entomology. Technical assistance was

provided by Dr. Andrew Rogers, retired, HRS, and the

late Dr. Maurice Provost, Florida Medical Entomology

Laboratory. The manual was edited and produced by

the IFAS Editorial Department under the supervision of

JoAnn Pierce. Appreciation is expressed to the U. S.

Department of Health and Human Services (USHHS),

and to extension specialists in neighboring states for

valuable ideas and visual aids. Credit is due to the late

Paul J. Hunt, and John Gamble, East Volusia Mosquito

Control District, and Thomas M. Loyless, Bureau of

Entomology and Pest Control (BEPC) of FDACS for

photographs of equipment and habitats.

Thanks are due to Dr. Carlyle B. Rathburn,

retired, John A. Mulrennan, Sr. Public Health

Entomology Research and Education Center for the

section on calibration of equipment, Dr. Philip Koehler,

Department of Entomology and Nematology, IFAS,

University of Florida, and William R. Opp, retired, Lee

County Mosquito Control District for additional

technical assistance.

The last edition was updated and revised in May

2001 by Thomas M. Loyless, FDACS, with assistance

from Edsel M. Fussell, Florida Keys Mosquito Control

District, Mark Latham, Manatee County Mosquito

Control District and Stephen Sickerman, FDACS

(currently with the South Walton Mosquito Control

District).

This edition was updated and revised in 2011 by

Dr. Yongxing “Peter” Jiang, with assistance from Dr.

Dave Daiker, Angela Weeks-Samanie, and Joe Claborn of

the Florida Department of Agriculture and Consumer

Services, Dr. Jeff Stivers, Collier Mosquito Control

District, and Dr. Rui-de Xue, Anastasia Mosquito Control

District.

The Department would like to extend a special thanks to Joe Claborn for the

cover photograph of the St. Marks River and mosquito breeding habitats.

Table of Contents

Acknowledgements .................................................................................................................................................. i

Introduction .............................................................................................................................................................. 1

History of Mosquito Control in Florida ............................................................................................................... 1

Anti-Mosquito Association ..................................................................................................................................... 1

Formed ............................................................................................................................................................. 1

Division of Entomology Created ................................................................................................................ 2

Entomological Research Center Established .......................................................................................... 2

Mosquitoes ................................................................................................................................................................ 3

How to Recognize a Mosquito .................................................................................................................... 3

Classification .................................................................................................................................................. 3

Importance to Health and Economy ......................................................................................................... 3

Mosquito Species in Florida ................................................................................................................................... 4

Mosquitoes and Their Production Sites in Florida ..................................................................................... 5-12

Identification ........................................................................................................................................................... 12

Larval Morphology ...................................................................................................................................... 15

Adult Morphology ....................................................................................................................................... 15

Some Problem Species of Mosquitoes in Florida ............................................................................................ 16

Common Problem Mosquitoes ................................................................................................................. 16

Other Problem Mosquitoes ....................................................................................................................... 16

Mosquito Control Practice ................................................................................................................................... 20

Responsibilities of a Mosquito Control Director .................................................................................. 20

Continuing education ................................................................................................................................. 20

Planning the Project.................................................................................................................................... 21

Equipment for Mosquito Control ............................................................................................................. 23

Larviciding Equipment ............................................................................................................................... 23

Adulticiding Equipment ............................................................................................................................. 23

Calibration of ULV Machines and Checking Droplet Size ................................................................... 23

Calibration of Thermal Fog Equipment .................................................................................................. 24

Maintenance of Equipment ....................................................................................................................... 24

Methods of Mosquito Control .............................................................................................................................. 24

Premise Sanitation ...................................................................................................................................... 24

Land and Water Management .................................................................................................................. 24

Chemical Control ......................................................................................................................................... 25

Larvicides ........................................................................................................................................... 25

Adulticides.......................................................................................................................................... 25

Other Control Methods .............................................................................................................................. 26

Legal Aspects of Mosquito Control..................................................................................................................... 27

Public Relations and Managing Negative Impacts.......................................................................................... 27

Arthropods of Public Health Importance ......................................................................................................... 28

Control of Other Arthropods by Mosquito Control Districts ....................................................................... 29

Sand Flies ............................................................................................................................................ 30

Stable Flies ......................................................................................................................................... 30

Blind Mosquitoes .............................................................................................................................. 30

House Flies ......................................................................................................................................... 30

Eye Gnats ............................................................................................................................................ 30

Miscellaneous Insects ...................................................................................................................... 30

Glossary .................................................................................................................................................................... 32

Bibliography ............................................................................................................................................................ 34

Figure 1. Florida and its counties

Introduction

The State of Florida has made great progress

in reducing the hordes of malaria-carrying Anopheles

and salt marsh mosquitoes which, in years past,

harassed visitors and Floridians alike. Many miles of

salt marsh stretching down the east and west coasts of

the State have been ditched or impounded by the

mosquito control districts, making the coastal areas

habitable and opening them to development for housing

and as tourist resorts.

There is no question that the control of salt

marsh mosquitoes has made a major contribution to the

development of the tourist industry in this state;

without this control, tourists would not have repeatedly

visited to enjoy the beaches and attractions. Figure 2

gives a good picture of the relationship, showing the

steady rise in income from tourism plotted against the

steady decline of the major salt marsh pest mosquito,

Aedes taeniorhynchus.

Mosquitoes occur throughout the world,

breeding in almost every known aquatic habitat except

very swift currents and in open bodies of water.

Wherever they occur, mosquitoes are, for humans, at

best an annoyance and at worst vectors of deadly

diseases. Over 3,000 species have been described

worldwide and they display a broad range of habitats.

Larvae may be found in such diverse places as the

grassy margins of ponds, land crab holes, and aquatic

plants. Depending on the species, eggs may be laid

singly or in rafts, on water or on damp soil where they

hatch in subsequent flooding. Flight ranges also vary

among species from a few hundred feet to more than

eighty miles with favorable winds. Hibernation or

overwintering in different species may be in the egg

stage, as larvae, or as adults. Each of these variations

among species can affect the efficiency of any measure

utilized to control them.

Figure 2. Average number of female Aedes

taeniorhynchus per light trap

History of Mosquito Control in Florida

Florida is the leading tourism destination in

the United States, and, in terms of dollars spent, it is the

number one vacation destination in the world.

Florida, with more than 1,200 miles of

coastline, a warm subtropical climate, and heavy

rainfall, produces an unusually rich fauna, including 80

species of mosquitoes.

We often forget that Florida was not always a

vacation paradise where people could escape for

warmth, recreation and relaxation. As little as 100 years

ago, many parts of Florida were considered unbearable,

thanks in large part to legions of mosquitoes. Pestilence

and disease raged, and many people said the State could

not be developed. When Congress was debating the

merits of statehood for Florida, John Randolph of

Virginia stated that Florida could never be developed,

nor would it ever be a fit place to live. He described the

land as a "land of swamps, of quagmires, of frogs and

alligators and mosquitoes."

The battle with the mosquito, however, was a

long, tough fight and there were many casualties. The

mosquito was such a plague when the Spaniards arrived

that they named what today is Ponce de Leon Inlet,

"Barro de Mosquitoes." Since the time of the earliest

maps, some of Florida's inlets, lagoons, and sections

have borne the name Mosquito. In the 18th Century, the

part of Florida lying between the St. Johns River and the

coastal lagoons north of Cape Canaveral was called "The

Mosquito Country," or "The Mosquitoes."

In 1824, when Mosquito Country became a

county which included a large portion of peninsular

Florida, government officials could think of no more

appropriate name than "Mosquito County." Today, that

county is known as Orange County and is home for

many of our major attractions in and around Orlando.

For many years settlements in Florida were

restricted to the northern tier of the state. The

peninsular portion of Florida was a series of swamps,

lakes, rivers, and hammocks populated mostly by

hoards of mosquitoes and other biting insects.

Although northern Florida was settled, it was

anything but a pleasant place to live. It suffered from

disease, hardship, and poverty; the major cities of

Jacksonville, St. Augustine, Tallahassee and Pensacola

were known as the "malaria belt."

Summer routinely brought swarms of

mosquitoes and deadly fevers to the region. Commerce

was seriously curtailed and those who could afford it

fled to the north for relief. Those forced to stay behind

faced the threat and certainty of disease. One of the

worst sieges of disease was the yellow fever epidemic in

1877 in Jacksonville and Fernandina Beach. It was

described by historians as the State's worst holocaust.

Fernandina Beach, with a population of 1,632, had

1,146 persons ill with the fever. Twenty-four died. In

1887, yellow fever epidemics raged in Key West,

Tampa, Plant City, and Manatee. The 1888 epidemic in

Jacksonville saw 10,000 persons (out of a population of

26,700 in Duval County) flee the city in carriages, drays,

wagon trains, and ships.

All of that has changed thanks to mosquito

control. Consider, for example, the success story of

mosquito control at Sanibel Island. On Florida's rapidly

expanding southwest coast, Sanibel is one of the resort

jewels our State offers, fantastic weather, incredible

sunsets, great beaches, and fine resorts. Sanibel has it

all. But without mosquito control, it would be virtually

uninhabitable. In fact, the island was once so heavily

infested with mosquitoes that bred in the vast grassy

marshes that the local postman had to make his rounds

in July dressed like an Eskimo in a parka and netting.

Anti-Mosquito Association Formed

No organized effort was made to control

mosquitoes in Florida as a way of preventing malaria

until World War I when the U.S. Army, U. S. Public

Health Service, and the State Board of Health set up a

program of drainage and larviciding at Camp Johnson,

near Jacksonville. In 1919, the State Board of Health, the

city of Perry, and the Burton Swartz Cypress Company

jointly set up a malaria control project in the city of

Perry, one of the most malarious areas of the State. At

that time the Perry project was one of the largest

malaria control projects in the country and was the first

non-military control project in Florida.

Mosquito control in Florida was given impetus

in 1922 by the formation of the Florida Anti-Mosquito

Association (FAMA) (now known as the Florida

Mosquito Control Association, FMCA), with Dr. J. Y.

Porter, the State's first Health Officer, serving as its

president. The Indian River County Mosquito Control

District was established in 1925, followed by St. Lucie

Mosquito District in 1926, Broward County Mosquito

Control District in 1934 and Dade County Mosquito

Control District in 1935. By 1975, there were 52

mosquito control districts in Florida, and that number

has remained fairly constant to the present day.

From the depression year of 1933 until funds

were withdrawn in 1941, many malaria control projects

were performed with funding from the Civil Works

Administration, Emergency Relief Administration of the

Works Progress Administration. During this period,

more than 1,500 miles of drainage ditches were dug

throughout the state to eliminate mosquito breeding

habitats.

In 1941, a Bureau of Malaria Control was

created within the Division of Health and in 1942, the

U.S. Public Health Service set up the first Malaria

Control in War Areas project in Florida near

Tallahassee. Similar projects were then established

around all military bases in the state. A program of DDT

residual house spraying in malarious areas of Florida

was supported by U.S. Public Health Funds from 1945

through 1949.

Division of Entomology Created

In 1946, the Bureau of Malaria Control was

abolished and a Division of Entomology was created

within the Bureau of Sanitary Engineering. In 1953, the

Division was raised to Bureau status. In 1976, the

Bureau of Entomology became the Office of Entomology

and in 1986, became Entomology Services in the

Department of Health and Rehabilitative Services. The

program was moved to the Department of Agriculture

and Consumer Services (DACS) in 1992, where it is now

known as the Bureau of Scientific Evaluation and

Technical Assistance (BSETA). The functions of the

BSETA include promoting control of insects of public

health importance, serving as advisors and consultants

for mosquito control districts, and administering all

state funds appropriated for nonagricultural arthropod

control work. State laws were passed in 1925, 1929,

and 1941 which set up methods for establishing self-

taxing mosquito control districts and in 1949, a State

law was passed that provided State aid to districts in

the form of insecticides, materials, equipment,

personnel, and vehicles.

In 1953, the State Legislature passed a second

State aid law whereby any board of county

commissioners or mosquito control district that places

funds in its budget for control of "arthropods of public

health importance", would, upon proper certification,

receive funds directly from the State of up to 75 percent

of the funds appropriated by the county or district.

These funds were to be used for permanent control

measures; additional appropriations were given as

matching funds for either permanent or temporary

control measures.

This act has been amended several times. At

present, it provides that a county or district shall be

eligible, upon approval of the Department of Agriculture

and Consumer Services, to receive state funds. The

amount and type of State aid currently available to

mosquito control agencies is described in Chapter 5E-

13. 030 Florida Administrative Code (F.A.C.)

Entomological Research Center Established

In 1953, the legislature appropriated money to

establish the Entomological Research Center at Vero

Beach to study the biology and control of arthropods of

public health importance in Florida. The center was

dedicated in 1956 and has become world renowned for

the excellence of its facilities and its research. In 1973,

the name was changed to the Florida Medical

Entomology Laboratory and, in 1979, it was transferred

to the University of Florida, Institute of Food and

Agricultural Sciences.

The John A. Mulrennan, Sr. Public Health

Entomology Research and Education Center (JAMS

PHEREC), formally the West Florida Arthropod

Research Laboratory, was established at Panama City in

1963. Its primarily mission was to study the biology and

control of the "dog fly," known elsewhere as the stable

fly (Stomoxys calcitrans), which plagues people on the

Gulf beaches in summer, and to test the efficacy of

various insecticides on mosquitoes and other

arthropods. In 1992, JAMS PHEREC was transferred to

Florida Agricultural and Mechanical University, College

of Engineering Sciences, Technology and Agriculture,

but its overall mission remains unchanged.

MOSQUITOES

How to Recognize a Mosquito

Mosquitoes are insects with long slender

bodies, narrow wings with a fringe of scales on the hind

margin and along the veins, and long, very thin legs. In

females, the elongate proboscis is firm and usually

adapted for piercing and sucking blood. Male

mosquitoes cannot suck blood, and survive on nectar.

Females are also required to feed on nectar of various

plants to obtain sugar for energy, but rely on a blood

meal for egg-laying.

There are four life stages: egg, larva, pupa, and

winged adult. Eggs may be laid singly or in rafts,

deposited in water, on the sides of containers where

water will soon cover them, or on damp soil where they

must undergo a maturing process before they can hatch

when flooded by rainfall or high tides. Mosquitoes of the

genus Mansonia deposit their eggs on the underside,

and, less so, on the upper side of floating aquatic plants

such as water lettuce and water hyacinth. After the eggs

hatch, the larvae or wrigglers begin to feed on very

small plant and animal particles, going through four

growth stages or instars before becoming pupae. With

the exception of species in the genera Mansonia and

Coquillettidia, larvae of other species all breathe air at

the surface of the water. Species of Mansonia and

Coquillettidia, in contrast, have a sharp pointed siphon

which pierces the roots and stems of aquatic plants to

obtain oxygen from the plant. The pupal or tumbler

stage is comparatively brief, does not feed, and is active

only if disturbed. Upon maturation, the pupa emerges

from the surface of the water, splits the chitinous pupal

skin and the adult emerges. After a brief time on the

surface to dry its wings, the adult flies away.

Classification

In order to make it clear exactly which animal

among the many kinds one is speaking or writing about,

scientists have devised a system of classification and

naming in which each kind of animal known to science

is given a name consisting of two words. The first name

is the name of the genus and is written with a capital

letter. Mosquito publications, however, often abbreviate

the genus name using a two-letter abbreviation, for

instance, Ae. for Aedes and Cx. for Culex. The second

name is a specific name and begins with a small letter.

Together they form the species name which is always

either italicized or underlined (to indicate italics). The

classification of the mosquito which transmitted

malaria in the southeastern United States is shown

below:

Kingdom - Animalia (all animals)

Phylum - Arthropods (all animals with paired,

jointed appendages and

exoskeletons)

Class - Insecta (all insects; three main body

divisions and six legs)

Order - Diptera (true flies, all two-winged flies

with the hind wings reduced

to knobbed structures called

halteres)

Family - Culicidae (all mosquitoes)

Genus - Anopheles

Species - Anopheles quadrimaculatus Say (Say is the

person who first described the species)

Currently, 80 species of mosquitoes, belonging

to 12 different genera, have been recorded in Florida.

These mosquitoes inhabit a wide variety of aquatic

habitats, and the biology of each of these species is

unique in some way. Unique distinctions between

species include larval habitat, host preferences, and

flight ranges, and will be discussed in more detail in the

section focusing on various mosquito species. The

differences in appearance (morphological differences)

are discussed in the section on identification.

Importance to Health and Economy

In years past, malaria, yellow fever, and

dengue were present in the State in epidemic

proportions. Through mosquito control, these diseases

are now no longer endemic. However, Anopheles

quadrimaculatus, which transmits malaria and Aedes

aegypti, which vectors both yellow fever and dengue,

are still present in large numbers, and if persons

carrying the disease in their bloodstreams should come

into Florida from other areas, it would be possible for

mosquitoes to bite them and become infected. In this

way, a new cycle of these diseases could begin.

Although secondary infections may result

from scratching mosquito bites, and there are people

who are allergic to the bites, the chief medical concern

in Florida at the present time is the possibility of an

arthropod- borne encephalitis epidemic. Viruses of

Eastern Equine Encephalitis, Western Equine

Encephalitis, St. Louis Encephalitis, California

Encephalitis and Venezuelan Equine Encephalitis have

been found in mosquitoes in the State.

Eastern Equine Encephalitis Eastern

Equine Encephalitis (EEE) is an enzootic disease that

was first recognized in Massachusetts, in 1831 when 75

horses died of an encephalitic illness. The casual agent,

Eastern Equine Encephalitis virus (EEEV), is an

alphavirus that was first isolated from infected horse

brains in the 1930s and currently occurs in focal

locations of the eastern United States including Florida.

EEE is capable of infecting a wide range of animals

including mammals, birds, reptiles and amphibians. The

virus is maintained in natural cycles involving birds and

Culiseta melanura in freshwater swampy areas with a

peak of activity between May and August. In this usual

cycle of transmission, the virus does not escape from

the swampy areas because the mosquito species,

Culiseta melanura, prefers to feed upon birds and does

not usually bite humans or other animals. However,

transmission of EEEV to mammals occurs via bridge

vectors because they bring the virus from avian

populations to mammalian populations. These bridge

vectors include Coquillettidia perturbans, Aedes

atlanticus, Culex nigripalpus, Cx. quinquefasciatus and

Aedes solicitants. These species feed on both birds and

mammals and can transmit the virus and cause disease

in people, horses, dogs and some birds such as

pheasants, quail, ostriches and emus.

Most persons infected with EEEV have no

apparent illness. However, symptoms of severe cases of

EEE include sudden onset of headache, high fever, chills,

and vomiting. The illness may then progress to

disorientation, seizures, or coma. EEE is one of the most

severe mosquito-transmitted diseases in the United

States with approximately 33% mortality and

significant brain damage in most survivors.

Despite there having been only 81 human

cases documented in Florida in the past fifty years

(1957-2008), the State averages over 70 reported

equine cases each year. In years when conditions favor

the spread of EEE, the number of reported cases can

exceed 200, with over 90% of the affected horses dying.

The distribution of EEE cases have predominantly been

in areas north of Lake Okeechobee, including panhandle

areas (Walton, Holmes, Jackson, Leon, Jefferson,

Madison and Escambia Counties); the lower St. Johns

River areas (Duval, Volusia, Flagler, Putnam and Clay

Counties); and the green swamp region area (Lake,

Orange, Pasco, Polk, Osceola, Pinellas, Hillsborough and

Manatee Counties).

A vaccine is available for horses, but not for

humans. Preventive measures should include effective

mosquito control and avoidance of mosquito bites by

using insect repellent, wearing protective clothing, and

staying indoors while mosquitoes are most active.

St. Louis Encephalitis St. Louis

Encephalitis (SLE) was first recognized in the vicinity of

St. Louis, Missouri and the neighboring St. Louis County

in 1933 when an encephalitis epidemic broke out. Over

1,000 cases were reported to the local health

departments and the newly constituted National

Institute of Health. St. Louis encephalitis virus (SLEV), a

flavivirus, is one mosquito-transmitted viral disease

that is of great medical importance in North America.

During summer, SLEV is maintained in a mosquito-bird

cycle, with periodic amplification by birds and Culex

mosquitoes.

Normally less than 1% of SLEV infections in

humans are clinically apparent and the vast majority of

infections remain undiagnosed. The occurrence and

severity of SLE in humans is strongly dependent on age.

The case fatality rate in Florida SLE epidemics has

ranged from 4-30 percent. Deaths were almost

exclusively among people age 50 and older. It is not

uncommon for those surviving severe cases of SLE to

suffer long-term residual neurological damage, which

include paralysis, memory loss, or deterioration of fine

motor skills.

Major SLE outbreaks occurred in Florida in

1959, 1961, 1962, 1977 and 1990. The epicenter of the

outbreaks in 1961 and 1962 was the Tampa area. In

1961, there were 25 cases with 7 deaths and in the

following year, there were 222 cases with 43 deaths.

One very interesting discovery made at the time was

that the SLE virus was vectored by Culex nigripalpus, a

species which had not been previously implicated in

disease transmission. In other parts of the United States,

SLE is transmitted by Culex quinquefasciatus and Culex

tarsalis. In addition to the illnesses and deaths caused

this epidemic also greatly reduced tourism business.

The reductions were estimated to be as high as $40

million, which added an enormous economic loss to the

human loss and suffering.

West Nile Encephalitis In 1999, a new

form of encephalitis was discovered in the New York

City area. Known as West Nile Encephalitis (WNE), it is

believed to have been brought in from the Middle East

by unknown means and, previous to its introduction,

had never been identified from the Western

Hemisphere. West Nile Virus (WNV) is a flavivirus that

was first isolated in 1937 from a woman in the West

Nile province of Uganda in Central Africa. WNV was first

found in the United States in 1999 during an outbreak

of the disease involving humans, birds and horses in

New York and New Jersey. Since then, the virus has

spread and by the end of 2004, it had been detected in

48 states and close to 30,000 human cases had been

confirmed through 2009 nationwide. WNV was first

detected in Florida in the summer of 2001 when it was

found in a dead crow in eastern Jefferson County.

Twelve human cases were reported in the State that

year. In 2002, 35 human cases of WNV illness were

detected in Florida. The peak occurred in 2003 with 99

human cases confirmed. In recent years, there have

been only a few cases annually. Since its initial WNV

activity, the virus has been reported in all 67 Florida

Counties.

Like SLEV, to which it is closely related, WNV

is maintained in a mosquito-bird cycle in nature. Culex

quinquefasciatus and Culex nigripalpus are two major

vectors of WNV in Florida. However, unlike SLE, WNV

causes high mortality in certain bird species, most

notably crows, jays, hawks and owls. It is also

pathogenic in horses. More than 1,000 cases of equine

WNV infection were confirmed in Florida from 2001-

2009.

The peak period of WNV transmission in

Florida is from July to September and most seriously

affects people older than 50 years of age. Most people

bitten by a WNV-infected mosquito will not show any

sign of illness. Of those who become clinically ill, about

20 percent will display mild symptoms including fever

and lethargy and less than 1% experiences the

neuroinvasive form of the illness. Symptoms appear

between 3 and 14 days after the bite of an infected

mosquito.

The national fatality rate has generally been 2

to 5 percent. In Florida, case fatality rates range from

4% for all cases to 7% among those who develop the

neuroinvasive form of the disease.

To prevent epidemics of encephalitis, a

surveillance program was established in the early

seventies. This surveillance includes gathering data on

cases of horses with encephalitis; checking the blood

sera of wild birds, sentinel chicken flocks, and small

mammals for the presence of encephalitis antibodies;

keeping a record of central nervous system diseases

reported from Florida hospitals; and checking

mosquitoes from certain areas of the State during the

summer and fall to screen for encephalitic viruses.

Mosquito Species in Florida

Each species of mosquito has not only certain

specific morphological characteristics, but also

physiological characteristics and habits which are

distinctive to that species. For each species, there is, for

instance, a preferential egg-laying site, a normal flight

distance/range, a preferred host animal or plant. In

addition, there is a definite temperature tolerance at

each stage of development. This range of tolerated

temperatures may be very wide or very narrow,

depending on the species. There is typically a maximum

temperature above which the animal will die, a

minimum below which it will die, and an optimum

temperature at which maximum development takes

place in a minimum of time. Both temperature and

humidity are critical for adult mosquitoes. In most

insects, the longer the optimum temperature is

maintained, the greater the number of generations the

insect may produce at a given place in a season.

Florida mosquitoes breed mainly in the

summer. Exceptions include Anopheles punctipennis,

Culex restuans and Culex salinarius, which breed all

year-round but reach peak numbers in late spring. In

north Florida, most mosquito populations are lower in

winter because of the colder temperatures, while in

south Florida, the reduced mosquito breeding

associated with winter is due to a lack of rainfall. Of the

80 species of mosquitoes found in Florida, 36 occur

throughout the State. Some of the remaining species

occur in most of the southeastern United States and the

extreme southern limit of their range falls in northwest

Florida or as far south as central Florida. Other species

which are of tropical origin cannot be found north of the

sub-tropical area of Florida - that is, the area south of a

line from Punta Gorda across to Lake Okeechobee, then

north along the coastal counties through Brevard

County (see Figure 3). A few of these species are found

only in the tropical zone, south Dade County and the

Florida Keys.

Figure 3. Fanual Zones

Figure 4. Mangrove Swamps Figure 5. Salt Marsh

Mosquitoes and Their Production Sites in Florida

Certain areas of Florida are characterized by

generally poor drainage. Muck, marl and other soils

perpetually saturated or subject to flooding make up nearly

half of the total land area of the State. These vast areas of

wetlands, together with thousands of grassy lake margins,

constitute an enormous potential area for mosquito

breeding.

Mosquitoes are not adapted to life in moving waters

and where they occur in flowing streams they occupy the quiet

pools and seepage areas. Aquatic environments differ chiefly in:

(1) chemistry of the waters -acid or alkaline, fresh, salt or

brackish; (2) whether natural or man-made; (3) amount of

vegetation, or type of vegetation present; and (4) whether

shady or sunny. The distinctive ovipositing habits of each

species of mosquito determine its larval habitat.

Types of Mosquito Habitats

Types of aquatic habitats are not always clearly

separate and definable, but in general they may be

classified as follows:

Salt Water or Brackish

Mangrove Swamps (Figure 4). – It is in

the transitional zone from the usual level of high tide to

levels above all but the highest spring and storm tides

that the heaviest mosquito breeding occurs, because

plant and grass cover keep moisture conditions suitable

for egg laying. Eggs are usually laid on sloping sides of

potholes, ditches, sloughs, marsh edges or on the sides

of small depressions. In some cases, however, egg-

laying occurs in extensively grass-covered level areas.

The eggs of some species require alternate flooding and

drying before hatching will occur. Species most often

occurring in these areas include:

Aedes taeniorhynchus

Aedes sollicitans

Anopheles atropos

Culex nigripalpus

Salt Marshes (Figure 5) . - North of

Daytona Beach on the east coast and north of Port

Richey on the west coast of Florida, the mangrove

swamps are largely replaced by grassy salt marshes.

Salt-tolerant herbaceous plants and typical salt grasses

dominate this type of habitat. Extensive areas are often

covered by a single species such as salt grass Distichlis

spicata, or by Batis maritima or Salicornia perennis. It is

in association with one of these plants or with black

mangrove, Avicennia nitida that breeding of the

following species occurs:

Aedes taeniorhynchus

Aedes sollicitans

Figure 6. Salt or Brackish ditch

Figure 7. Freshwater Marshes

Figure 8. Freshwater Lake

Salt or Brackish Ditches (Figure 6). -

The ditches which lie adjacent to salt water marshes

contain many species of grasses and support a larger

mosquito fauna including:

Aedes taeniorhynchus

Aedes sollicitans

Aedes atlanticus

Psorophora columbiae

Anopheles bradleyi

Culex pilosus

Psorophora howardii

Psorophora ciliata

Freshwater Marshes (Figure 7). - Nearly

all coastal areas have both freshwater marshes and

brackish areas, often adjacent to each other. The

shoreline along the western coast from Pasco County to

Franklin County is bordered by coastal marshes, with

little or no beach. In the Everglades, sawgrass marshes

cover more than 1.25 million acres, with Cladiurn

jamaicense the dominant low ground cover plant.

Mosquito species often found in freshwater marshes

include:

Anopheles walkeri

Anopheles crucians

Psorophora columbiae

Culex nigripalpus

Culex salinarius

Culex tarsalis

Culex erraticus

Culex peccator

Lakes (Figure 8). - There are two general

types of lakes in Florida, sand bottom and silt bottom.

Sand bottom lakes are more numerous but they do not

afford as many mosquito habitats as the silt bottom

lakes. Vegetation, usually composed of emergent

grasses, occurs only in a narrow band along the margin

and larvae are confined to this littoral zone. Silt bottom

lakes are frequently bordered by cypress trees and

many species of floating or emergent plants. The lake

bottom consists of a layer of organic detritus made up of

decaying vegetation and the lake usually has a fairly

heavy cover of vegetation composed of such plants as

water hyacinths or bonnets. Mosquito larvae are more

common near shore but may be found throughout the

lake wherever cover is afforded. Species likely to be

found in lakes and marshy areas around lakes include:

Anopheles smaragdinus

Anopheles crucians

Anopheles quadrimaculatus

Anopheles walkeri

Uranotaenia sapphirina

Uranotaenia lowii

Culex salinarius

Culex nigripalpus

Culex erraticus

Culex peccator

Coquillettidia perturbans

Mansonia dyari

Mansonia titillans

Ponds and Seepage Areas (Figure 9). -

There is no clear distinction between a pond and a lake

except that ponds are generally smaller. Grassy

woodland ponds or fluctuating ponds occupy shallow

depressions and are filled by rainwater or surface run-

off. They are usually of uniform depth but the area they

cover will vary, depending on rainfall. Sinkhole ponds

are usually quite deep and may be covered with

vegetation or free of all except marginal plants. Both

these types of ponds may contain larvae of:

Anopheles crucians

Anopheles quadrimaculatus

Culiseta inornata

Culiseta melanura

Culex nigripalpus

Culex quinquefasciatus

Culex restuans

Culex salinarius

Culex erraticus

Culex peccator

Culex pilosus

Culex territans

Aedes canadensis canadensis

The seepage areas around hillsides and ponds or

streams most often breed:

Anopheles punctipennis

Anopheles georgianus

Anopheles quadrimaculatus

Aedes sticticus

Psorophora ferox

Springs (Figure 10). - Mosquito breeding in

springs is restricted to the quiet edges where vegetation

affords cover for the larvae and there is little if any

water movement. The only species recorded from this

habitat in Florida are:

Anopheles quadrimaculatus

Anopheles perplexens

Figure 9. Ponds and Seepage Areas

Figure 10. Springs

Swamps (Figure 11). - Swamps differ from

marshes principally in having a more dense cover made

up of larger trees such as cypress, red maple, and

tupelo. The most common species of mosquito larvae

found in swamps are:

Anopheles smaragdinus

Anopheles maverlius

Anopheles inundatus

Anopheles diluvialis

Anopheles crucians

Anopheles quadrimaculatus

Culiseta melanura

Aedes canadensis

Mansonia species

Coquillettidia perturbans

Borrow Pits and Canals (Figure 12)

. - These

man-made bodies of open water produce more

Figure 11. Swamps

mosquitoes as they silt-in and become overgrown with

vegetation. They yield this variety of species:

Anopheles maverlius

Anopheles quadrimaculatus

Culiseta inornata

Psorophora columbiae

Aedes canadensis

Culex nigripalpus

Culex quinquefasciatus

Culex restuans

Culex salinarius

Anopheles albimanus

Coquillettidia perturbans

Mansonia species

Specific Aquatic Plant Associations (Figure

13). - Species of mosquitoes found in association with

specific aquatic plants are:

Coquillettidia perturbans

Mansonia dyari

Mansonia titillans

Bromeliads and pitcher plants

Wyeomyia vanduzeei

Figure 12. Borrow Pits and Canals

Wyeomyia mitchellii

Wyeomyia haynei

Culex biscaynesis

Figure 14. Rain and Flood Water Pool

Figure 15. Tree Holes

Figure 16. Land Crab Holes

Rain and Floodwater Pools (Figure 14). -

These transient pools form the breeding place for a

large number of species, especially among the

Psorophora and Aedes. The pools disappear in dry

weather and support no true aquatic vegetation, though

there is usually a layer of leaves and other detritus

settled on the bottom. Mosquito species found in this

habitat are:

Psorophora johnstonii

Psorophora pygmaea

Aedes atlanticus

Aedes dupreei

Aedes fulvus pallens

Aedes infirmatus

Aedes mitchellae

Aedes sticticus

Aedes tormenter

Aedes vexans

Aedes cinereus

Culex atratus

Culex pilosus

Culex bahamensis

Culex nigripalpus

Tree Holes (Figure 15). - Tree holes or rot

cavities support a rather extensive and unusual

mosquito fauna, with many species breeding almost

exclusively in this habitat. They are:

Anopheles barberi

Toxorhynchites rutilis rutilis

Toxorhynchites rutilis septentrionalis

Aedes triseriatus

Aedes hendersoni

Orthopodomyia sianifera

Orthopodomyia alba

Aedes thibaulti

Aedes albopictus

Crab holes (Figure 16). - Along the eastern

coast of Florida south of St. Johns County the holes of

the large land crab, Cardisorna guanhumi , serve as

larval habitat for:

Deinocerites cancer

Culex opisthopus

Freshwater Drainage Ditches (Figure 17). -

Freshwater ditches in pastures, at the bottom of road

shoulders, in old fields, and in lowland groves will often

yield the following species of mosquito larvae:

Psorophora columbiae

Culex nigripalpus

Culex pilosus

Culex erraticus

Culex quinquefasciatus

Anopheles crucians

Anopheles walkeri

Aedes atlanticus

Uranotaenia sapphirina

Uranotaenia lowii

Psorophora ciliata

Aedes sollicitans

Figure 17. Freshwater Ditch

Artificial Containers (Figure 18). - Several

species breed in man-made situations around human

dwellings. Tin cans, fish pools, rain barrels, bird baths,

and old tires containing water serve as the larval

habitat. Species most often encountered are:

Aedes aegypti

Aedes triseriatus

Culex quinquefasciatus

Culex restuans

Culex salinarius

Culex nigripalpus

Anopheles quadrimaculatus

Aedes albopictus

Figure 18. Artificial Containers

Identification

Mosquitoes can be collected as either larvae or

as adults and many species can be identified in either

life phase. It is important to determine what species are

present and their relative abundance so that mosquito

control personnel will know what their problem

mosquitoes are and where they are breeding. Only in

this way can they most efficiently use the control tools

available. Every person who works in mosquito control

should be able to recognize the common problem

species in their area.

All mosquito species in Florida fall into one of

these subfamilies: Toxorhynchitinae (genus

Toxorhynchites); Anophelinae (genus Anopheles); or

Culicinae (the other ten genera).

Figure19. Fourth Stage of Anopheles and Culex Larvae

Figure 20. Characteristics of Anophelines and Culicines

The larvae of Toxorhynchitis are found in tree

holes or artificial containers. They are very large and

predacious, feeding on such mosquito larvae and other

small animals as they occur in their breeding place.

They have an almost square head and the hairs on the

thorax and abdomen arise from heavily chitinized

plates. The females do not take blood as adult

mosquitoes, but feed only on plant nectar and juices.

Anopheline larvae (Figure 19) are

characterized by the absence of a siphon, and the

presence of a palmate (palmetto-shaped) hair dorsally

on each side of, at least, segments IV-VI of the abdomen.

Anopheline larvae usually lie parallel to the surface of

the water.

Culicine larvae always have a siphon (Figure

19) which may or may not bear a pecten, a row of

spines. They do not have palmate hairs. These larvae

usually lie with the head downward at a 45 degree

angle to the water surface.

With practice it may be possible to identify

some species as adults or as fourth instar larvae with

the unaided eye or a hand lens. However, because it is

easy to misidentify in the field, samples should be taken

into the laboratory to be verified under a microscope. A

stereoscopic microscope to be used for adult and larval

identification should have a magnification range of 10X

to 40X, the lower power for use in sorting specimens

that are readily identifiable and the higher power for

detail work. Specific identification of difficult larval

characteristics or male terminalia may require

magnifications of up to 400X.

Larval Morphology

The characters used in the identification of

genera of mosquitoes found in Florida are clearly

labeled in Figure 19. By studying these illustrations it

will be possible to key fourth instar larvae to genus,

using Figure 22.

Adult Morphology

The external anatomy of an adult female

mosquito is shown in Figure 21. The Pictorial Key to the

12 genera found in Florida (Figure 23) makes it possible

to identify females to genus by comparing distinctive

features. You simply follow the character in each pair

which fits the specimen you are identifying, following

the lines down until you reach the correct choice which

names the genus.

Some Problem Species of Mosquitoes in Florida

Common Problem Mosquitoes

The primary pest mosquitoes in Florida are

the salt marsh species, Aedes taeniorhynchus and Ae.

sollicitans. Ae. taeniorhynchus is a small black and white

mosquito with distinct narrow white rings on the tarsi

and on the proboscis. Wing scales are all dark. Ae.

taeniorhynchus is the predominant species, produced in

huge numbers, all around the coast of Florida.

Eggs are usually deposited on damp soil where

ground vegetation is thick. Sod samples have yielded up

to 100 million eggs per acre. The larval embryo is fully

developed in about three days and is ready for hatching

as soon as it is flooded by the tides or rainfall. The

longer the period is before hatching, the greater the

chance of the embryo dying, although some of the eggs

will hatch after many months.

The length of time passed as a larva, before

pupation, depends on temperature and available food,

and ranges from four days to four weeks. The pupal

stage may last from 30 hours to several days, depending

on temperature. Emergence from a breeding area may

go on for several days. Mating may occur during the

general flight activity of a newly hatched brood. The

adult rests for at least six to eight hours and after dark,

a large number will migrate, flying as far as 25 miles,

usually downwind and parallel to the coast. Migration

may be repeated on a second or third night and then the

brood settle down to feed, rest, and lay eggs. Adults feed

on nectar as an energy source.

A blood meal, taken only by females, serves as

a source of protein for egg production, although some

Ae. taeniorhynchus are capable of laying eggs without

the first blood meal, by utilizing protein carried over

from the larval stage. This species is active chiefly after

sunset. During the day the mosquitoes rest on the

ground where grass or leaves offer a dark, moist, cool

hiding place. However, if a stimulus reaches them, they

will fly to it. It is not uncommon that if you go where

they are in the daytime, they will be stimulated to bite

you.

Aedes sollicitans occurs around the entire coast

of Florida, but is more common in the northern half of

the State. In localized situations, it may outnumber Ae.

taeniorhynchus. Ae. sollicitans is somewhat larger than

Ae. taeniorhynchus and is more golden brown with

wider, pale bands on tarsi and proboscis. The wing

scales are mixed light and dark. Each abdominal

segment has a median longitudinal band of pale scales

in addition to the pale basal transverse band. This

species has a life history similar to that of Ae.

taeniorhynchus, breeding in the salt marsh, but the

larvae have also been found in great numbers in coastal

swales and inland in brackish waters. The adults usually

rest during the day, but the females are persistent biters

and will attack at any time of night or day.

The exact seasonal distribution of the salt

marsh species is dependent on the tides and on rainfall,

but usually each year they begin to emerge in large

numbers in May and continue through October.

The other main problem species in Florida

include the flood-water species (Psorophora columbiae,

Ps. ferox, Aedes atlanticus, Ae. infirmatus, and

Ae. mitchellae) which breed in intermittently flooded

areas of fresh water, as well as Culex nigripalpus, Cx.

quinquefasciatus and Cx. salinarius, which usually breed

in more permanent fresh water habitats such as ponds

and ditches. In many areas of Florida, Coquillettidia

perturbans emerges in enormous numbers, and in

central and south Florida, Mansonia dyari is a serious

pest. In the spring, Aedes canadensis and Ae. sticticus

emerge in large numbers in northwest Florida, although

they are comparatively rare in the rest of the state.

Other Problem Mosquitoes

Aedes aegypti is a small, dark, mosquito easily

recognized by the silvery-white lyre-shaped marking on

the thorax and the silvery-white bands on the tarsi.

Historically, it was one of the most common domestic

mosquitoes, laying its eggs on the sides of containers

such as tin cans, tires, vases, small pools, tree holes and

yard plantings of certain bromeliads. Its numbers,

however, have been drastically reduced in north and

central Florida by, as yet, unknown factors related to

the recent introduction of Aedes albopictus, (see

narrative of Aedes albopictus below). The embryos

develop in two to four days and will hatch when

flooded. The cycle from egg to adult may be completed

in 10 days in warm weather.

The adults feed warily, often biting the ankles.

They never fly more than a few hundred feet from the

emergence site. Because this mosquito is the vector for

both yellow fever and dengue fever, campaigns have

been instituted in various countries of this hemisphere

to eradicate the species, including a project within the

last three decades to eliminate them in this state. The

project was discontinued, however, before completion

and Ae. aegypti became at least as common, if not more

numerous, than before the eradication project.

Figure 22. Pictorial Key to U.S. Genera of Mosquito Larvae

Figure 23. Pictorial Key to U.S. Genera of Female Mosquitoes

Aedes albopictus, "the Asian Tiger Mosquito",

was introduced from Asia into Florida in 1986 and has

expanded its range to every part of the State but the

middle and lower keys. In northern and central Florida,

Ae. albopictus is replacing the related species, Aedes

aegypti, in areas where the two mosquitoes share

breeding sites. Similar to Ae. aegypti in size, appearance,

and habits, this mosquito can be identified by the single,

silver, longitudinal line on the thorax and by the

strongly contrasting silver and jet black body

coloration. An aggressive daytime biter, Ae. albopictus is

considered a major vector of dengue in Asia. While

dengue has disappeared from Florida for many years,

the recent introduction of this mosquito into the U.S.

has some officials concerned about the increased

potential for epidemics of this viral disease.

The larvae of Aedes triseriatus are usually

found in water collected in rot cavities of trees, although

they frequently occur in artificial containers along with

Ae. aegypti, and Ae. albopictus. The adult is dark with a

conspicuous area of white shiny scales on each side of

the thorax. Near their breeding place these mosquitoes

will attack man during the day or early evening and

their bite is painful and lasting.

Aedes mitchellae is similar in appearance to Ae.

taeniorhynchus in being black with pale rings on the

proboscis and tarsi. It differs in having the femora and

tibiae speckled with pale scales and in having a

longitudinal stripe or patches of pale scales on the

abdomen in addition to the pale basal abdominal bands

on each segment. It breeds in stump holes and flood-

water pools. Ae. mitchellae is a severe biter, common in

the northern and panhandle areas of Florida.

Aedes atlanticus is a dark, medium-sized,

species which has a distinct median pale stripe running

the length of the thorax. This mosquito lays its eggs on

damp soil and the larvae develop in the shallow pools

following rainfall. The adults bite readily, even in

sunlight. It is often found in association with Ae.

infirmatus, which has a broader pale stripe that extends

only about two-thirds the way back on the thorax. This

species bites readily.

Aedes canadensis canadensis, which has pale

rings both at the base and tip of the tarsal segments, is a

common nuisance flood-water mosquito in the northern

section of Florida. Aedes vexans, distinguished by its

very narrow pale tarsal bands and by basal abdominal

bands which are notched medially on the posterior

border, is common throughout most of the state. It

usually feeds in shady places during the day, but is often

particularly annoying at dusk and after dark. The larvae

are often found in large numbers in irrigated groves.

Psorophora mosquitoes commonly breed in

flood-water and include Ps. ciliata, a very large shaggy

black and yellow species commonly called the "feather-

legged gallinipper". Ps. ferox is a smaller purplish

mosquito with conspicuously white tips on the hind legs

(tarsal segments 5, 4 and part of 3); and Ps. Columbiae is

a large black and white species distinguished by a pale

subapical ring on each femur. Psorophora columbiae is

one of the most troublesome pests in Florida. It will bite

viciously any time of the day or night, but is especially

active at night. It has been known to feed in such

numbers in the everglades that cattle were lulled by

loss of blood and suffocation. The adults emerge in huge

numbers from improved pastures and irrigated groves

and from woodland pools, roadside ditches, and swales.

There are three main problem Anopheles

mosquitoes in Florida. Anopheles crucians adults have

distinct areas of pale scales on the wing. This species

breeds chiefly in the slightly acidic waters of cypress

swamps and in ponds and lakes. It has been found

naturally infected with malaria, but is not considered an

important vector of the disease since it apparently

prefers to feed on large mammals rather than man.

Anopheles quadrimaculatus is the most

common and widespread member of a larger species

complex consisting of 5 morphologically distinct but

similar species. Although very similar in appearance,

they can be separated with great care and differ

somewhat in their preferred habitat and range.

Anopheles quadrimaculatus breeds mostly in stagnant

alkaline fresh water which has emergent or floating

vegetation or debris. It was the primary vector of

malaria in the southeastern United States. The adults

are characterized by having four, more or less, distinct

spots on the wings. They feed actively on man and

animals, chiefly at night or sometimes in the day in dark

areas in and around buildings. There may be as many as

10 generations in a season.

Anopheles atropos larvae are found in

permanent brackish to salt pools and marshes. The

adults, entirely brownish black, will attack man readily,

even in bright sunlight. The species is not considered a

disease vector.

Culiseta inornata, a very large species

breeding in pools, ditches and occasionally in artificial

containers, is primarily a late fall and winter breeder in

Florida. The adults apparently prefer to feed on

livestock, but also will attack man.

Culiseta melanura, a smaller, very dark

species, breeds in small permanent bodies of water,

particularly in freshwater swamps. Females feed chiefly

on birds and the species is considered to be the primary

vector of Eastern Equine Encephalitis from bird to bird.

Coquillettidia perturbans is the most common

and wide-ranging of the mosquitoes whose larvae

breathe by piercing the roots or stems of aquatic plants

with their siphon. This species has been identified in

every county in Florida. Many aquatic plants may serve

as host to this species, including water lettuce, water

hyacinths, and cattails. Although the females usually

feed at night, they have been known to feed on man

during the day in shady areas where they are resting.

This species is suspected of being an important

secondary vector of EEE to horses and man. Cq.

perturbans is a fairly large species with a golden brown

coloration, while the other two species are smaller,

darker, and are very difficult to distinguish from each

other. Mansonia titillans larvae also attach to a number

of different aquatic plants, but Ma. dyari in Florida has

been found associated primarily with water lettuce.

The Culex mosquitoes all breed in fresh water

habitats such as pools, ditches, and ponds. Culex

quinquefasciatus larvae are often associated with foul

water such as effluents of sewage treatment plants,

which have been found producing these mosquitoes by

the thousands. The larvae are also taken in catch basins,

cesspools, polluted ditches and ponds, and in containers

holding water in homes and around buildings. The

adults are distinguished by having a pale basal band on

each abdominal segment rounded on the apical margin

so that the band is wider in the middle and narrower on

each side. The females are said to show a preference for

bird blood, but they often get into homes and feed

readily on man at night. In some areas of the country,

this species is the primary vector of St. Louis

Encephalitis (SLE).

Culex salinarius larvae are often found

associated with Cx. nigripalpus larvae, and have been

collected occasionally from small ground depressions

and stump holes. Emergences are concentrated in the

cooler months. The females will bite readily outdoors

and sometimes enter buildings to feed on man. The

species is characterized by golden scaling on the entire

seventh abdominal segment.

Culex nigripalpus is a small black mosquito

with white lateral abdominal patches. It breeds in

permanent or semi-permanent waters where there is an

abundance of decaying leaves and vegetation. Larvae

have also been found in brackish water. This species

usually bites outdoors. It was formerly believed to be of

little medical importance, but during the St. Louis

Encephalitis epidemic in the Tampa Bay area in 1961

and 1962, it proved to be a primary vector of the

disease. Since that time extensive studies of the life

history of this mosquito have been carried out at the

Florida Medical Entomology Laboratory at Vero Beach.

This mosquito is readily taken in light traps.

Culex restuans larvae occur in a variety of

freshwater habitats. In Florida, adults appear primarily

during cooler weather. Females will sometimes come

into homes and bite after dark, but they are not a

primary nuisance, preferring birds to humans. The adult

is similar to Cx. quinquefasciatus except that the

abdominal bands are straight on the apical margin and

the thorax often has four small patches (spots) of pale

scales.

In contrast to these previously mentioned

species, some species of mosquitoes are not a big

problem, but may be extremely annoying in local areas

where they breed. For instance, Deinocerites cancer;

which breeds almost exclusively in water collected in

land crab holes, will bite humans who come to their

breeding habitat. Three species of Wyeomyia, small

mosquitoes which breed in water collected in plants,

occur in Florida. One of these, Wy. vanduzeei, which

breeds in bromeliads, will feed and be very annoying if

humans come into their vicinity.

Mosquito Control Practices

Responsibilities of a Mosquito Control

Director

The qualifications for a mosquito control director,

depending on the size of the local budget for mosquito

control, are set out in the Mosquito Control Rules,

Chapter 5E-13, F.A.C.. It is the duty of the director to

plan, supervise, and direct the execution of the county

or district arthropod control program. This makes the

director responsible for every aspect of the working

program, including:

1) Determining the extent of the problem and

locating the breeding areas.

2) Planning appropriate projects and controls to

alleviate the problems.

3) Preparing and submitting for approval the

monthly reports as required by Chapter 5E-13,

F.A.C.

4) Purchasing equipment and materials,

providing for maintenance, and maintaining

inventory records.

5) Hiring and assigning necessary personnel.

6) Seeing that all work is carried out in a safe,

effective and efficient manner in compliance

with the Federal, state, and local laws and all

regulations pertaining to mosquito control.

7) Evaluating the results the program achieves

and providing for surveillance of breeding

conditions in the county or district.

8) Establishing good public relations for

mosquito control.

9) Continually improving his knowledge and

abilities through local and national

associations, meetings and publications.

A mosquito control director must be able to

depend on the abilities and integrity of his supervisors

and equipment operators. The supervisor of a crew

operating heavy equipment or applying insecticides

must give his crew clear and complete instructions,

must see that all safety precautions are adhered to, and

that all equipment is kept in good working condition.

In the final analysis, the success of a program

often depends on the correct application of insecticides,

on the ability and willingness of the applicator to use

the materials and equipment as instructed and to

immediately report malfunction of equipment. This

ensures the correct dosage is applied without

endangering the applicator, the public or the

environment. It is important for every ground

equipment operator and pilot to know how to safely use

his equipment, how to calibrate and check it, and how to

maintain it. Accurate record keeping is an essential for

evaluating the effectiveness and efficiency of insecticide

adulticiding.

Continuing Education

In order to do the best possible job in any field,

it is necessary that employees know of new methods

and materials that can help them to better accomplish

their purpose. Each new employee should be fully

trained for his job -what he is expected to do, how he is

to do it, and why. It is good practice to have refresher

and updating courses on insecticide usage and safety

practices for all employees. This is especially important

for employees holding PHPC certifications, as this

license is renewed through the accrual of 16 hours of

continuing education every 4 years.

The director of the program should keep up

with new developments in mosquito control through

reading technical journals and pamphlets, by talking

with representatives of equipment and chemical

companies, and by belonging to and attending meetings

of associations in his field. One of the most useful

journals for directors is the Journal of the American

Mosquito Control Association (AMCA). Annual meetings

of the AMCA and the Florida Mosquito Control

association (FMCA) will also prove helpful, both as a

source of new ideas and for an exchange of information

and ideas with other directors.

Planning the Project

Before any control effort is made, the director

must know the extent of the problem in his area. He

must know what species are involved, the level of

annoyance from mosquitoes, and the location of

breeding areas. Even after the initial survey, routine

checking (surveillance) will be needed because of

seasonal variations in the fauna, because of changes in

the topography, and as a means of evaluating how the

projects are progressing.

To identify the problem, larvae and adults

should be collected throughout the area. To ensure

effective control, it is very important to be able to

identify the location for each collection. Collecting sites

may be identified by an address, such as "fish pond at

634 Lane Avenue", by description such as "in pasture

pond at intersection of State Road 84 and U.S. 1", or by

using a map or GIS coordinates. Additional data on the

collection site such as a list of dominant vegetation or

evidence of gross pollution is useful. Larval collections

are usually made with a long-handled dipper and counts

are based on the number of larvae per dip. The larvae

are usually preserved in alcohol for later identification

in the laboratory.

In marshes, larval dipping is sometimes done

from a hovering helicopter, making it possible to check

breeding areas not otherwise accessible to the

inspector.

Adult mosquito surveys are most often made

using light traps. The New Jersey trap is operated using

a standard household current and is a good choice when

convenience and long-term monitoring from a

permanent site are important. New Jersey traps,

however, tend to also collect larger organisms, i.e.

beetles, moths and frogs, which can damage the

collection and make identification difficult (Figure 24).

The CDC miniature light trap, (Figure 24) baited with

dry ice to release carbon dioxide will usually capture

much larger numbers of mosquitoes and may attract

some species which do not usually come to the New

Jersey trap in significant numbers. CDC traps are

compact and highly portable but are operated by

batteries which need fairly frequent recharging or

replacing. It is important to note that traps are selective

and only give an indication of what species are present

and their relative abundance.

Figure 24. CDC miniature light trap (left) and New Jersey light trap (right)

Other methods of judging the extent of the mosquito

problem include landing rate counts -the number of

mosquitoes which land per minute -and collecting by

aspirator in fixed resting stations such as culverts,

sheds or houses. The number of telephone complaints

received by the mosquito control office is also an index

of the magnitude of the problem, but should be relied

upon only when followed up by inspection or when

taken from individuals who have a proven history of

reliability.

In locating breeding areas and in planning

source reduction projects, the director must have

accurate knowledge of the topography of his district.

For example, his program must be aware of the size and

position of streams, lakes and roads and the elevation

throughout the area. In addition, he will want to know

the location of recreational areas, wildlife reserves,

state and national parks, large bridges, towers and

power lines. Among the maps which will be especially

useful are: shaded relief maps, road maps, population

maps, soil maps, drainage maps, and aerial

photographs. Plans for engineering projects for

mosquito control can be shown as map overlays, and

areas to be sprayed by plane can be marked on the

maps for the pilot's use.

Figure 25. Comparing ULV (left) and Thermal Fogging (right)

Equipment for Mosquito Control

Each mosquito control district is different and

will need a different combination of vehicles and other

equipment.

Larviciding Equipment - One of the oldest methods

of mechanical application of larvicides is by

knapsack/backpack sprayer or by using a hand-

operated granular applicator. In the interest of covering

a larger area more quickly, manual application has been

largely replaced by more mechanized methods.

However, the knapsack sprayer is still often used in

urban areas, along drainage ditches and in catch basins

where it is desirable to make a very localized larvicide

application. With the exception of applications made to

roadside ditches and other areas readily accessible to

ground vehicles (i.e. trucks), larviciding of large areas is

usually done by making applications from airplanes and

helicopters.

Adulticiding Equipment - Control of adult

mosquitoes is usually accomplished through fogging,

spraying, or by ultra-low volume (ULV) spraying.

Mosquito control districts in Florida may own a variety

of vehicles and equipment such as: cars, station wagons,

jeeps, fog trucks, tractors, draglines, bulldozers,

backhoes, pick-up trucks, airplanes, and helicopters.

Tractors, bulldozers, and backhoes are used in

diking, filling, and impounding, as well as in operating a

sanitary landfill in such a way that it does not breed

flies or mosquitoes. This type of control activity can be

considered habitat reduction.

A variety of fogging and spraying equipment is

available and includes mist blowers, "cold foggers",

thermal fog generators, and ULV machines.

Aircraft equipped for conventional spraying,

or adapted for ULV applications are widely used

throughout the State, both for larviciding and

adulticiding. Helicopters are often used both for

larviciding and adulticiding and may be used for both

larval surveys and for applying larvicides. However,

fixed-wing aircraft, both single and multi-engine, are the

aircraft most commonly used by the control districts for

both adulticiding and larviciding. Use of fixed-wing

aircraft is the most efficient means to adequately treat

large areas of land.

Calibration of ULV Machines and

Checking Droplet Size

ULV application of pesticides is a method

whereby the insecticide, usually a technical or undiluted

material, is broken up into very small droplets. Most

equipment uses the air blast of a blower to break up the

droplets and transport them away from the vehicle, but

some machines use other methods to produce and move

the small droplets. The primary reason a piece of

equipment must be calibrated is to make sure it is

operating in an effective manner and discharging the

insecticide in the correct amounts according to label

recommendations of the particular insecticide.

The calibration of ULV equipment is a

relatively simple process since it requires a minimum

amount of equipment. A timepiece, preferably a stop

watch, and two containers (one to collect the insecticide

and one for measuring) should be sufficient to measure

insecticide flow. Obviously, when discharging only ½ to

4 fl. Oz/min (15 to 125 ml/min) as with ULV sprayers, a

measuring container calibrated for small amounts is

required. A glass container marked in milliliters (ml) or

tenths of a fluid ounce is ideal.

To calibrate ULV equipment, first, disconnect

the insecticide line from the nozzle and place the tip of

the line in a container to collect the discharge. Start the

machine and when it is operating at the desired

pressure, etc., set the flow meter or digital readout

about mid-scale of where you think it should be for the

desired discharge. While the material is being

discharged into the collection container, move the

discharge line to the calibrated measuring container for

a predetermined time, usually 1min. At the end of that

time, move the discharge line back to the collection

container and record the amount that was discharged

into the measuring container. If the discharge is too

much, reduce the setting and repeat the procedure; if it

is too little, increase the setting. Repeat the entire

procedure as many times as necessary until the

permanent mosquito control projects such as ditching,

machine is dispensing the recommended volume per

minute. Repeat at the same setting as a check. If the

discharge is satisfactory, reconnect the insecticide line

to the nozzle. The recommended discharge in fl. oz/min

for a particular insecticide is shown on the insecticide

label.

If the machine is equipped with the older ball

type flow meter control system, the temperature of the

insecticide at the time of calibration should be noted

since the amount of material being discharged at a

particular flow meter setting will vary according to the

temperature of the insecticide. If the temperature in

actual operation is less than when calibrated, the

discharge will be less and in order to discharge the

correct amount of insecticide, the flow meter setting

will have to be increased. For example, when spraying

malathion with the Leco generator, a 5°F difference in

temperature will result in a 1/2 fl. oz. difference in

discharge. Therefore, when discharging 2 fl. oz/min,

there is an unacceptable 25% error in discharge.

Variations in temperature do not affect all insecticides

equally. Some equipment manufacturers offer tables or

curves which indicate the flow meter setting for several

insecticides at various temperatures and discharge

rates. In machines which have positive displacement

pumps, such as the variable flow and constant flow

control systems, insecticide temperature is not a factor.

The insecticidal distribution system of the ULV

machine should be flushed with approximately one pint

of isopropyl alcohol following each time the unit is used.

Once a ULV machine has been calibrated to

deliver the correct dosage of an insecticide, it is

necessary to determine whether the insecticide is being

dispersed in the correct droplet sizes. Instructions for

testing droplet size are given on some insecticide labels.

Recent improvements in testing for droplet

size include the use of a stand with a wooden arm to

which slides are attached. The arm is dropped through

the insecticide coming from the machine. This

mechanism gives a more uniform deposition rate than

waving the slides by hand; however, it works only with

machines that use a blower to propel the droplets from

the nozzle.

Since droplet size varies with flow rate,

different formulations, and formulation pressure, as

well as, to some extent, with temperature, it is

important to check droplet size frequently. It is

recommended that droplet size be checked each time

the unit is put into service following repairs or

maintenance. The droplet size should be verified every

100 hours of operation or as often as necessary to

ensure it is producing droplets in the required range.

Calibration of Thermal Fog Equipment - Since

thermal foggers discharge much greater volumes than

ULV equipment, a larger measuring container must be

used. Because of the low viscosity of the dilute

insecticide solution, the temperature of the solution is

not a factor in determining discharge rates.

Maintenance of Equipment - The importance of

proper maintenance cannot be overemphasized.

Machine breakdown is both annoying and expensive.

Because timing is often of great importance in adult

mosquito control, a machine failure can completely

destroy the value of any specific operation. An

instruction manual and a parts manual should be

available for each piece of equipment and they should

be kept at hand. Both the machine operator and his

supervisor should be familiar with their contents.

Methods of Mosquito Control

Premises Sanitation

The need to prevent mosquito breeding in

water holding containers around homes and businesses

is well known, but unfortunately has not received much

emphasis in recent years. Each mosquito control

director should use the media available to him to

educate the general public in the need to see that jars,

cans, old tires and other junk, bird baths and water-

holding plants do not breed mosquitoes. Removing

these items or dumping any water in them is a simple

step that can be taken to help combat certain species of

mosquito.

Land and Water Management

Land and water management methods do, in

many instances, alter the environment and are,

therefore, subject to the environmental permitting

process. In the past, ditching in the salt marshes to

provide water circulation and to make the marshes

available to fish which feed on mosquito larvae has been

widely and successfully carried out in Florida. Another

effective method of salt marsh mosquito control has

been diking and creating an impoundment which covers

the surface of the marsh with shallow water and

prevents salt marsh mosquitoes from laying eggs, since

they are laid on damp soil and not on water.

Unless specifically exempt, most dredging and

filling activities require permits if the activity is to be in

"submerged lands or the transitional zone of submerged

lands" as defined by the vegetation indices listed in

Chapter 17-4, Florida Administrative Code.

The application for a permit is submitted to

the Department of Environmental Protection who in

turn sends copies to other state agencies and the U.S.

Army Corps of Engineers. The applicable water

management district should also be contacted to

determine if a permit from them is required. A local

permit is not usually needed, but this should be

investigated.

Existing projects which need maintenance

may be exempt from the permitting process, especially

if the spoil is to be placed on an upland site as defined in

Chapter 17- 4, F.A.C.

The Department of Agriculture and Consumer

Services, Bureau of Scientific Evaluation and Technical

Assistance, will assist mosquito control districts in

developing permit applications so that water

management work may remain an essential element of

mosquito control programs.

Chemical Control

Throughout the world the chemical control of

mosquitoes has significantly reduced human illness and

death, and has greatly improved human comfort by

rapidly and effectively reducing vector species and pest

populations. Although the use of chemical materials has

been a publicly sensitive issue, chemical insecticides

have been responsible not only for creating a healthier

environment for human beings, but also for making it

possible to develop and utilize land areas previously

considered unfit for human habitation.

Chemical insecticides are used in Florida both

as larvicides and as adulticides. With certain exceptions,

no chemicals may legally be used for these purposes

unless they have been approved by the Environmental

Protection Agency (EPA) and registered by the Florida

Department of Agriculture and Consumer Services.

Larvicides

Three categories of larvicides are used

extensively for larval control in Florida. These include

contact larvicides (certain organophosphate and

hormone mimics), surface control agents (surface oils

and films), and stomach toxins (microbial larvicides).

Temephos belongs to the class of insecticides

known as organophosphates (OP). Temephos is

currently the only OP registered for use as a larvicide in

Florida. Like the other OPs, the mode of action is to

inhibit cholinesterase in the peripheral and central

nervous systems of the larval mosquitoes. Temephos

has a relatively low to moderate acute toxicity

compared to other organophosphate insecticides.

Registered formulation types containing temephos

include granular and emulsifiable concentrates. Product

labels typically bear either the signal word “WARNING”

or the signal word “CAUTION”, indicating they are of

lower irritancy or toxicity. Temephos products are

labeled for use in many habitats including tidal

marshes, woodland pools, polluted water, tires, and as a

pre-hatch treatment.

Methoprene is a juvenile hormone (JH)

analog which can be used as a larvicide, since it can

regulate insect growth. Methoprene will not control

adult insects. Juvenile hormone must be absent for a

pupa to molt to an adult. Methoprene effectively inhibits

the transformation of a pupa to the adult insect. It is

considered a biochemical pesticide because rather than

controlling mosquito larvae through direct toxicity,

methoprene interferes with an insect’s life cycle and

prevents it from reaching maturity or reproducing.

Therefore, EPA lists methoprene as a biopesticide, and

its labels bear the signal word “Caution”.

Larviciding Oils form a coating on the top of

the water and drown larvae, pupae, and emerging adult

mosquitoes. Surface oils are considered one of the most

effective tools for pupal control and can control newly

emerged adults that are resting on the water surface

when drying their wings. Over all, they have a low

toxicity when used according to the label with minimal

detrimental effects to non-target organisms. EPA has

also assigned larviciding oils a “CAUTION” signal.

Monomolecular surface films such as

Arosurf MSF and Agnique MMF are utilized as larvicides

and pupicides of mosquitoes. They are biodegradable

and spread spontaneously over the surface of the water

to form an ultra-thin film. Their mode of action is

physical rather than chemical. These compounds lower

the water surface tension, preventing suspension of the

larvae and pupae at the water surface, subsequently

suffocating them. They also interfere with emergence of

the adults. Monomolecular films, used according to label

directions for larva and pupa control, pose minimal

risks to the environment and human health. Because

they do not last very long in the environment, they are

usually applied only to standing water. Typical sites of

application include roadside ditches, woodland pools,

or containers which contain few non-target organisms.

Bacillus thuringiensis israelensis (Bti) and

Bacillus sphaericus (BS) are microbial larvicides that

occur naturally in soils and aquatic environments

globally. The active ingredients of Bti formulations are

delta-endotoxin crystals produced by various species of

bacteria. Mosquito larvae eat the Bti product that is

made up of the dormant spore form of the bacterium

and an associated pure toxin. The toxin disrupts the gut

in the mosquito by binding to receptor cells present in

insects, but not in mammals. Bti is registered as a

pesticide for control of mosquito larvae in outdoor

areas such as irrigation ditches, flood water, standing

ponds, woodland pools, pastures, tidal water, fresh or

saltwater marshes, and storm water retention areas.

Extensive testing shows that Bti does not pose risks to

wildlife, non-target species, or the environment, when

used according to label directions.

Bacillus sphaericus is another bacterial

larvicide that occurs naturally and is found throughout

the world. BS acts in a manner similar to Bti. The

bacteria are ingested by the mosquito larvae and the

toxin disrupts the gut in the mosquito by binding to

receptor cells present in insects but not in mammals. BS

toxins are much slower acting than Bti toxins but their

effectiveness is more persistent. Both Bti and BS are

classified as Biopesticides by EPA and both bear the

“CAUTION” signal word in their product labels.

Adulticides

Currently, two classes of pesticides are widely

used for the majority of adulticiding operations in

Florida. These are the organophosphates (OP) and

pyrethroids. The OP used in Florida includes malathion,

naled and chlorpyrifos. The pyrethroids consist of

pyrethrum, pyrethrins, permethrin, resmethrin,

lambda-cyhalothrin, cyfluthrin and D-phenothrin.

Etofenprox, a pyrethroid-like compound, was recently

registered and has been used to a small extent.

Malathion is an organophosphate (OP)

insecticide that has been registered for use in the

United States since 1956. Malathion kills mosquitoes

because it is converted inside the mosquito into mala-

oxon, which inhibits an important central nervous

system enzyme called acetylcholinesterase (AChE).

AChE breaks down the neurotransmitter, acetylcholine.

When this enzyme is inhibited by an OP, the

neurotransmission cannot cease and the nerve is over

stimulated. Ultimately, this overstimulation leads to

paralysis and death in the mosquito. All

organophosphate insecticides share this mode of action.

Malathion can be applied using both ground

and aerial equipment to control adult mosquitoes.

Malathion is a very effective chemical control agent and

when applied in accordance with the label

recommended rate and safety precautions, this

compound poses no unacceptable risks to human health

or the environment.

Naled is also an OP pesticide that is primarily

used for aerial adulticiding in Florida. It has a similar

mode of action again adult mosquito to malathion.

Naled is highly toxic to insects, and therefore is typically

applied at less than an ounce per acre. Like malathion,

the risks from naled to humans, birds, and fish are not

unacceptable. However, because of the invertebrate

toxicity of this compound, there are risks to non-target

invertebrates, including beneficial insects such as

honeybees. For that reason, EPA has established specific

precautions on the label to reduce such risk.

Pyrethrins are naturally-occurring

compounds derived from members of the

chrysanthemum family. Pyrethrins act on sodium

channels through which sodium is pumped to cause

excitation and nerve transmission. They prevent the

sodium channels from closing, resulting in continual

nerve impulse transmission, tremors, and eventually,

muscle paralysis and death. Since they are naturally

occurring compounds and break down rapidly in

sunlight, they are considered as environment-friendly

adulticides and have few negative residual effects.

Pyrethroids are synthetic chemical

insecticides whose structures mimic the natural

insecticide pyrethrum. Permethrin, resmethrin, and

sumithrin are synthetic pyrethroids commonly used in

Florida to control adult mosquitoes. Pyrethroids, like

pyrethrins, kill insects by overexciting their nervous

system. When used appropriately, pyrethroids used in

mosquito control programs should not pose

unreasonable risks to wildlife or the environment.

Pyrethroids, when applied at mosquito control rates,

are low in toxicity to mammals, and are practically non-

toxic to birds. However, pyrethroids are toxic to fish and

to bees. For that reason, EPA has established specific

precautions on the label to reduce such risks, including

restrictions that prohibit the direct application of

products to open water or within 100 feet of lakes,

streams, rivers or bays.

Other Control Methods

The Department of Agriculture and Consumer

Services has for many years stressed the importance of

permanent control, but because chemical insecticides

have been questioned by environmentalists in recent

years, additional emphasis has been put on research to

find alternative methods of controlling mosquitoes.

Biological control of a population through an increase in

predators or pathogens affecting the organism to be

controlled has been practiced in mosquito control for

many years. For instance, digging minnow-access

ditches into a salt marsh or stocking mosquito breeding

areas with fish, which feed on larvae are two such

means to control mosquitoes. However, opposition by

special interest groups and recently enacted legislation

restricting the construction of ditches, have all but

eliminated this biological control method for mosquito

control.

Researchers are also continuing to study

bacterial, protozoan, fungal, algal, and viral diseases of

mosquito larvae. It is hoped that a number of effective

biological control agents may be discovered from these

efforts.

Mosquito control programs may also apply

herbicides to kill aquatic weeds that provide protection

and, in certain species, oxygen for the larvae. Research

is also underway to determine the feasibility of using

the sterile male technique to control mosquito

populations. At the Florida Medical Entomology

Laboratory, researchers are studying lethal genes as a

hope for genetic control. But at the present time, none

of these methods are available and effective in practical

control operations.

Whatever methods of control may be used by

a district, it is of the utmost importance that they be

chosen carefully and used with utmost safety. This is

especially true in the use of chemical insecticides. Only

materials labeled for that particular use can be utilized.

These products should also be applied at the lowest

effective concentration, in strict accordance with the

label. The equipment used to apply the insecticide

should be properly calibrated and carefully checked,

and the applicator should be fully trained in the safe

handling and application of the material used. The

importance of using chemicals in the recommended

manner (i.e. proper rate, correct vehicle speed and

swath width) so that it is safe both to the environment

and to the applicator cannot be overemphasized.

Insecticides should be used only when absolutely

necessary and never on a routine basis.

Integrated Mosquito Management (IMM)

The most effective programs in mosquito

control are based on a combination of methods. These

include water/habitat management, chemical control

and biological control. This multi-tooled approach is

called "integrated control." To use integrated control

effectively, it is necessary to have a broad

understanding of the insects to be controlled and the

factors which influence population size. In this way,

costly chemical controls can be used only when really

needed and when they will be most effective.

In 2009, the American Mosquito Control

Association (AMCA) drafted a new policy document on

Integrated Mosquito Management (IMM). This

document was made available to EPA to help guide its

deliberations regarding National Pollutant Discharge

Elimination System (NPDES) permits. This document is

also discusses Best Management Practices (BMP) that,

when practiced by mosquito control agencies, will serve

as a basis for developing an Integrated Mosquito

Management (IMM) approach to mosquito control in

Florida. IMM is the use of a combination of biological,

chemical, educational and physical control methods in

order to maintain targeted mosquito species or

populations of mosquitoes at acceptable levels.

Legal Aspects of Mosquito Control

Mosquito control districts and programs are

established and operated under the authority provided

in the Mosquito Control Law, Chapter 388 Florida

Statutes (F. S .), and the Mosquito Control Rules,

Chapter 5E-13, Florida Administrative Code (F.A.C.).

Chapter 388 F.S. provides local governmental entities

authority to conduct arthropod control on public land,

under conditions specified in the law.

Performance of control measures on private

property requires permission of the owner. In cases

where the owner will not control arthropod breeding

on his property and refuses to permit the mosquito

control district to do so, it may be necessary to use the

authority provided in Chapter 386 F.S., Particular

Conditions Affecting Public Health. District Directors

are encouraged to work with the local Department of

Health officials and the homeowner to amicably resolve

and minimize potential health threats.

The Federal Insecticide, Fungicide, and

Rodenticide Act of 1972 requires that the EPA be

certain that all personnel handling hazardous or

restricted chemicals be trained to do so correctly and

safely, and that they be certified as pesticide applicators

by a responsible state or federal agency.

The state agency to administer the

certification is appointed by the governor of each state.

In Florida, the Department of Agriculture and Consumer

Services has been designated as the lead agency, and

shall be responsible for certifying the commercial pest

control operators and mosquito control personnel

making pesticide applications in the State. The law

requires that every person applying pesticides for

mosquito control, with certain exemptions, be certified

or be supervised by a certified applicator.

A mosquito control director is responsible for

upholding a number of laws and regulations related to

the safe use of pesticides and application equipment by

program employees. The director should ensure that all

applicators read and understand pesticide labels, that

they wear and maintain appropriate personal

protective equipment (PPE), that they follow the

recommended procedures in storing and mixing

chemicals, and in disposing of empty containers, that

they are well trained in proper operation of equipment,

and that they know and use good driving habits.

The director is also responsible for securing

adequate insurance for the district, and meeting the

requirements of the Social Security Act, "Right to Know"

law, and the Occupational Safety and Health Act (OSHA).

Public Relations and Dealing with Negative Impacts

To build a really effective mosquito control

program the general public must be made aware of the

need for mosquito control, the methods by which it is

accomplished, and the need for their support and

cooperation. How well a program is explained to the

public will determine not only the amount of tax money

the program receives, but the cooperation received

from land owners on whose property it is necessary to

work. It will influence the concern and cooperation

citizens give in trying to keep their premises free of

receptacles which might breed mosquitoes.

The public image of a mosquito control district

is created in three ways -through public coverage such

as newspaper stories and radio and television

announcements and programs, by talking before civic

organizations, schools and other groups, and by dealing

with individuals through telephone calls, letters or

personal contact.

The word "relations" in public relations

indicates that a relationship should exist and that the

process involves an exchange of information to and

from the public. Telephone calls and letters from the

public give the director an indication of where the

mosquitoes may be present at nuisance or public health

concern levels, how the public is reacting to the control

measures being used, and what the public wants done

that is not being done. This is invaluable information

and the director should follow-up complaints with

either an inspection or surveillance. In addition, every

employee of the district should be aware that the image

they create as they go about their job determines how

the public feels about mosquito control. Courtesy and

safety in driving, patience and consideration in dealing

with questions and problems, and care when working

on other people's property will give the public a

favorable view of the program.

Wherever a large scale mosquito control

program operates some negative impacts, both real and

perceived, will occur. Groups that occasionally oppose

some or all mosquito control activities include

environmental organizations, beekeepers, public lands

managers, aquaculturists, organic farmers, concerned

citizens, and chemically sensitive or chronically ill

individuals.

A mosquito control director has a

responsibility to work with these groups to achieve a

compromise acceptable to all concerned. The first step

is opening the lines of communication and to

developing trust. Often, the main problem is a lack of

understanding on both sides. Through education the

concerned party may better understand the need for,

and minimal impact of control operations and the

mosquito control director may realize how small

changes in the operation may significantly decrease the

possibility of adverse effects. Beekeeping is a good

example. Honey bees are susceptible to

organophosphates such as the adulticides naled,

chlorpyrifos, and malathion, and the larvicide

temephos. As a result, adulticiding during times of high

bee activity and larviciding over bee yards may have an

impact on the honey bee populations. Most aerial

adulticiding is now performed early in the morning

before bees leave the hive to forage, or in the evening or

at night when bees are back in the hives, thus

minimizing any impacts. In addition, mosquito control

personnel advise local beekeepers as to which areas will

have high, low, or no aerial activity allowing them to

locate their bee yards in "safe" areas. Beekeepers are

encouraged to inform mosquito control when they plan

to move their hives. If mosquito control is aware of bee

yards in or close to areas regularly treated, they can

tailor the operations to avoid impacts on the bees, such

as switching larvicides from temephos to a safer

material, such as methoprene or Bti.

Many mosquito control programs maintain a

listing of concerned citizens. Often these individuals

understand the need for mosquito control operations

but are fearful of exposure to any chemicals, despite

education and assurances from scientific experts. In

most cases, the solution to this problem is simple: the

district can call the concerned citizen(s) to inform them

of upcoming spray operations in their area. The citizen

can then take whatever precautions they deem

necessary to avoid exposure, and they feel mosquito

control has made an effort to work with them.

Arthropods of Public Health Importance

Mosquito control directors will often be asked

to identify, provide advice and possibly help in

controlling arthropods other than mosquitoes. Usually,

the questions relate to insects which bite or sting, but it

is not uncommon to receive questions about arthropods

which are annoying because of their abundance.

Among the insects which are frequently

reported as annoying are the blind mosquitoes

(Chironomidae) which may emerge from lakes of

Florida in such huge numbers that they make outdoor

living impossible and may even be a traffic hazard.

These insects are very similar to mosquitoes in

appearance, but they do not have scales on the wings

and the adults do not feed on blood. When very large

populations of these insects occur, it would be virtually

impossible for an individual to control these insects. A

mosquito control district can, however, cover a large

enough area with adulticides to give temporary relief.

The lovebugs (Bibionidae) are another major

annoyance in Florida. They fly into roadways in such

large numbers during peak emergences that

windshields are quickly covered with spattered insects.

The worst period is usually April through May, with a

secondary occurrence in September. Inside homes there

are sometimes populations of booklice (Psocidae) large

enough to create an annoyance by crawling on the skin.

These insects are not true lice and do not bite.

A number of people have entomophobia, a fear

of insects, and “suffer” from bites and crawling insects

on the skin which are often imagined rather than real.

Certain insects and arachnids are feared

because they can give a painful bite or sting. Those

which inject venom by biting include the black widow

spider, the brown recluse spider (not usually found in

Florida) and certain ticks. Those which inject venom by

stinging include scorpions, wasps, bees and fire ants.

The venom produces irritation at and around the site of

the injection. When the person is allergic to the venom,

more severe reactions may result including

anaphylactic shock and even death.

The urticating caterpillars inject their venom

through hollow body hairs. When a person brushes

against the hairs, venom passes from blades at the base

of the hair into the skin of the individual, producing a

very painful sting. The puss moth caterpillar,

saddleback, and IO moth caterpillar are the most

commonly encountered stinging caterpillars.

There also are a number of insects which shed

wing scales or hairs that may cause allergic reactions in

some individuals. Symptoms include itching and

dermatitis in sensitive individuals. The mouthparts of

many insects such as bedbugs, lice, some flies, mites and

ticks are constructed for blood sucking and in many

instances a blood meal is required for the female before

eggs can be developed and laid.

Dog flies (a.k.a., stable flies), sand flies, horse

or deer flies, fleas, chiggers and bird mites do not inject

venom when biting, but their saliva may be very

irritating or painful. Most of these insects do not usually

transmit diseases.

The larvae from a few fly species have been

known to survive internally in man, but these cases are

usually the result of accidental infestation and occur

infrequently. However, both flies and the screw worm

may lay their eggs in wounds or in the nostrils of man,

and the maggots can cause a very serious health

problem if not promptly treated by a skilled physician.

The role of mosquitoes in disease

transmission has been previously discussed. However, a

number of other insects are also involved in the spread

of human diseases.

Some examples of mechanical or passive

transmission of diseases would include the spreading of

"pink eye" or conjunctivitis by eye gnats, the spread of

typhoid and intestinal diseases by house flies and the

potential spread of pathogenic and food poisoning

organisms by cockroaches.

Aside from mosquitoes, the arthropod vectors

of diseases most likely to be encountered in Florida are

ticks and fleas. Although endemic typhus, spread by rat

fleas, was once widespread in the State, it is no longer a

concern here.

Rocky Mountain spotted fever, Lyme disease,

human ehrlichioses and tularemia are human diseases

which are vectored by ticks. The usual vector of Rocky

Mountain spotted fever, the American dog tick,

Dermacentor variabilis, occurs in Florida, but the

disease itself is almost unheard of in the State. Lyme

disease is caused by a spirochete and is found primarily

in the northeast and pacific coast areas of the U.S. The

disease is vectored by Ixodid ticks. The human

ehrlichioses are a complex of tick-borne rickettsial

diseases that are generally mild but may become

serious if not treated early. Cases of tuleremia do occur,

but in Florida most of these have been traced to dermal

contact with infected rabbits, and not tick bites.

A few cases of tick paralysis have been

recorded in Florida, usually in children who were found

to have one or more ticks attached near the hairline on

the neck. Careful removal of the ticks has been followed

by a swift recovery from the paralysis.

Mosquito Control directors should learn to

recognize the more common of these annoying or

dangerous arthropods, and should be able to provide

information on their life histories and control when

requested. The Florida Insect Control Guide will be

especially useful for this purpose.

Control of Other Arthropods by Mosquito Control Districts

In instances where insects other than

mosquitoes breed in such numbers as to be a serious

nuisance or a health hazard to the public, the mosquito

control district will often be called on to control these

insects or other arthropods. The most frequent

problems encountered are sand flies, dog flies, midges

(blind mosquitoes), house flies and other filth flies, and

eye gnats.

Sand Flies (Figure 26). - These small

biting midges of the genus Culicoides are a pest in many

areas of Florida, although the coastal species cause

more annoyance than the freshwater species. Much

research has been directed toward finding methods and

materials to effectively control these pests, but with the

exception of water management, no really satisfactory

method has been found. The only solution is to keep

their breeding areas flooded completely, or to fill them

and construct bulkheads at the shoreline.

Several chemical insecticides can be very

effective in killing sand fly larvae, but some of these

materials are also highly toxic to the aquatic fauna and

other wildlife. Panasol, a petroleum solvent, can be used

effectively as a larvicide and with safety to non-target

species; but because of the large volume required for

coverage, this larvicide is practical only for treating

shorelines. Research is being conducted with IGR

compounds, and they are showing promise as larvicides

for sand flies.

When sand fly adults are a problem in

populated areas, it is possible to fog or spray and

control them, but new adults move in from the

periphery so rapidly that relief is very temporary. In

addition, the results often do not justify the cost. Unless

the problem can be resolved by impounding or filling

the breeding area, the only real solution at the present

time is for people to try to remain inside air-

conditioned buildings when populations are high. If the

flies get indoors, household aerosols will provide

control. Repellents offer some protection for several

hours when one must be outside, but do not repel these

insects as well as they do mosquitoes. Fortunately,

these insects are seasonal in nature.

Stable Flies (Figure 27). - Also known as

dog flies, stable flies are a major pest along the

northwest Gulf coast from Wakulla County through

Escambia. The flies have a known flight range of up to

70 miles. In the past, the State had a modest

appropriation to carry out control operations which

would supplement the control operations of the

counties. Counties in the stable fly area should have

organized inspection and surveillance protocols for

stable fly outbreaks. Beaches must be inspected daily

for adult flies, starting at 8:00 a.m. and at least once or

twice more during the day, as long as north winds

prevail. Stable fly larvae should be controlled where

possible by management of plant and animal wastes to

destroy the larvae without the use of sprays. This can be

done by spreading waste materials thinly at intervals so

that they dry quickly.

Figure 26. Sand Fly

Figure 27. Stable Fly

Blind Mosquitoes (Chironomidae)

(Figure 28). - These mosquito-like insects do not bite,

nor carry disease. However, they are a nuisance when

they emerge in such large numbers that they make

outdoor activities unpleasant or impossible. Blind

mosquitoes have also been known to come to homes in

such huge numbers, attracted by the lights, that they

enter every time a door is opened.

Most complaints about midges come from the

lake regions in Polk, Orange, Lake, Highlands, and

Seminole counties, from sites along the St. Johns River

or its tributaries, or from the vicinity of man-made lakes

at apartment or condominium sites. Organic pollution,

including sewage treatment effluents, canning wastes

and fertilizer carried off by ground water, is responsible

for the heavy production.

In the past there have been several programs

for control of midge larvae with various insecticides. At

present, most efforts are directed toward control of

adult midges.

House Flies (Figure 29). - House flies and

other filth flies are capable of breeding in almost any

warm, moist organic matter such as animal manure,

garbage, or decomposing foods. Control of house flies

and other filth flies is usually best accomplished by

good sanitation, and the arthropod control districts are

called in only when an unusual situation causes a

problem population -such as an improperly managed

landfill. House flies have developed resistance to many

of the chlorinated hydrocarbon and organophosphate

insecticides. It is best to consult the most recent

recommendations for control before treating for flies.

Eye Gnats (Figure 30). - Until the last

decade, eye gnats were only a localized and temporary

problem in the State. However, with conversion of vast

tracts of woodlands in west Florida into farms for

growing soybeans and other crops, eye gnats have

become a significant problem. With eye gnats, as with

many problem insects, adulticiding offers, at best,

temporary relief. Newly emerged adults quickly reinfest

the sprayed areas. IGR compounds have shown promise

in current research for control of the larval stage.

Miscellaneous Insects. Mosquito control

districts often receive calls from private citizens seeking

information on how to control other certain household

pests, such as fleas, roaches, ticks, etc. Although

controlling these types of pests may not fall under the

mission of the program it is a good public relations step

to have the information at hand to give them. The

Florida Cooperative Extension Service, University of

Florida’s website

(http://edis.ifas.ufl.edu/topic_guide_ig_household_pests

_and_pests_of_man), is an excellent source of up-to-date

information on control.

Figure 28. Blind mosquito life cycle

Figure 29. House Fly

Figure 30. Eye Gnat

GLOSSARY

Arbovirus: Arthropod-borne viral disease agent transmitted biologically by insects.

Arthropod: An animal of the phylum Arthropoda characterized by having a hard exoskeleton, body with a number of

segments arranged longitudinally and paired jointed appendages. The phylum Arthropoda includes insects, spiders,

mites, ticks, scorpions, centipedes, millipedes, etc.

Calibration: The adjustment of pesticide application equipment to apply a pesticide formulation at a desired application

rate.

Cuticle: Thin, multilayered tissue covering insects and other arthropods. The outside layer is composed of proteins,

waxes and “cement”, while layers beneath contain chitin along with proteins and waxes penetrated by numerous pores

and glands.

DACS: Florida Department of Agriculture and Consumer Services.

Ditching: Creating ditches or furrows into a salt marsh to provide water circulation and to make the marsh available to

fish.

Eastern Equine Encephalitis (EEE): Eastern equine encephalitis is a viral disease that is spread to horses and humans

by infected mosquitoes. The causative agent, eastern equine encephalitis virus (EEEV), is an alphavirus that was first

isolated from infected horse brains in 1930s and currently occurs in focal locations of the eastern United States including

Florida

Enzootic: Animal diseases which are commonly present in a locality.

Exoskeleton: The hard or tough external covering of arthropods to which their muscles are attached and which serves

the same function as the bony skeleton of humans.

FAMA: Florida Anti-Mosquito Association.

Family: A group of related genera within an order.

Fauna: Animal life of a given area.

Faunal Zones: is a generic term for the list of animal species occurring in a particular region. Fauna can refer to a

prehistoric collection of animals, as might be inferred from the fossil record, or to a modern assemblage of species living

in a region. More locally, a faunation refers to the communities of individuals of the various animal species and occurring

in a particular place.

Flora: Plant life of a given area.

FMCA: Florida Mosquito Control Association.

FMEL: Florida Medical Entomology Laboratory, University of Florida, Institute of Food and Agricultural Sciences.

Genus (genera): A group of species considered more closely related to one another than to members of another genus

(plural is “genera”); the first word in the scientific name of a species is the name of the genus.

Impoundment: Coverage of the surface of a marsh with shallow water to prevent exposing substrate for salt march

mosquito egg laying.

Insect Growth Regulator (IGR): Synthetic insecticide which prevents normal development or causes delayed mortality

of insects by disrupting a natural physiological process.

Integrated Mosquito Management (IMM): The use of a combination of biological, chemical, educational and physical

control methods in order to maintain targeted species or populations of mosquitoes at an acceptable level.

Label: General and technical information about a pesticide product in the form of printed material attached to or printed

on the pesticide container.

Labeling: Technical information about a pesticide in the form of printed material provided by the manufacturer,

including labels, flyers, handouts, leaflets and brochures.

Landing Rate Count: A method of determining adult mosquito levels by counting all mosquitoes that land on the visible

portion of the body during a one minute period. Results are expressed as numbers of mosquitoes per minute.

Mosquito Control Law: Chapter 388 Florida Statutes (F. S.) makes provision for arthropod control to be conducted on

public land with certain conditions to be met.

Mosquito Control Rules: Chapter 5E-13, Florida Administration Code (F.A.C) to spell out mosquito control law.

Palpus (pl. palpi): Five-segmented paired sensory appendages projecting from the base of the proboscis.

PHEREC: The John A. Mulrennan, Sr. Public Health Entomology Research and Education Center, Florida A & M University.

PPE: Personal protective equipment.

Proboscis: Extended mouth structure of insects; the piercing mouth parts of a female mosquito which is made up of a

sheath-like structure (labium) enclosing piercing and sucking structures.

Seepage: Movement of water through the soil to form a pool on the surface.

St. Louis Encephalitis (SLE): Arboviral infection normally maintained in rural or urban areas as an enzootic cycle among

wild birds by Culex mosquito vectors. During mid to late summer, viral levels in the wild bird populations may be high

enough for transmission to humans by the same vector species.

Subfamilies: A taxonomic category of related organisms ranking between a family and a genus.

Tarsus (tarsi): The last segments of an insect’s legs; the “feet” of an insect (plural is tarsi).

Ultra-low volume (ULV): A spray application of a pesticide that is a technical or undiluted material and broken up into

very small droplets.

West Nile Virus (WNV): A flavivirus that is transmitted by mosquitoes.

Bibliography

Additional References on Mosquito Control and Mosquito Identification

1960. King, W. V., G. H. Bradley, C. N. Smith and W. C. McDuffie. Mosquitoes of the Southeastern United States.

Agriculture Handbook No. 173. Agricultural Research Service, USDA. 188 pp.

1968. American Mosquito Control Association. Ground Equipment and Insecticides for Mosquito Control. Bulletin No. 2.

1970. American Mosquito Control Association. Manual for Mosquito Rearing and Experimental Techniques. Bulletin No.

1977. U.S. Dept of Health, Education and Welfare. Mosquitoes of Public Health Importance and Their Control. (Revised)

HEW Publ. No. (CDC) 77-8140. U.S. Public Health Service C.D.C., Atlanta, GA 55 pp.

1982. American Mosquito Control Association. The Use of Aircraft for Mosquito Control. Bulletin No. 1. Revised.

1982. Breeland, S. G., and T. M. Loyless. Illustrated Keys to the Mosquitoes of Florida: Adult Females and Fourth Stage

Larvae. Journal of Florida Anti-Mosquito Assocation. 53(2): 63-84.

1983. Breeland, S. G., and J. A. Mulrennan, Jr. An Overview of Organized Mosquito Control in Florida. Mosquito News.

47(3): 276-280.

2000. Darsie, R. H. and C. D. Morris. Keys to the Adult Females and Fourth Instar Larvae of the Mosquitoes of Florida.

Bulletin of the Florida Mosquito Control Association, No. 1. (revised) 159 pp.

2004. Florida Mosquito Control Association. H. T. Evans' Florida Mosquito Control Handbook. Ed.: Rutledge C. R.

2004. Darsie, R. F., Jr., and R. A. Ward. Identification and Geographical Distribution of the Mosquitoes of North America,

North of Mexico. University Press of Florida.

2009. Florida Coordinating Council on Mosquito Control. Florida Mosquito Control (“White Paper”). Connelly C. R. and D.

B. Carlson, Co-Chairs, Steering Committee.