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In each state, there are many kinds of mosquitoes. This area has sixty
species, each of which has a different habitat, behavior and preferred source of
blood. About ten of these species are so numerous, and such vicious biters of
man and animals in the state, that many years ago, most counties
established agencies to control mosquitoes. Organized mosquito control is
necessary because mosquitoes are not only a nuisance as biting insects, but are
also involved periodically in transmitting disease to humans and animals.
Mosquito control agencies reduce mosquito populations in various ways,
including water management, biological control agents, and insecticides, which
can be effective in controlling mosquito larvae or mosquito adults.
Mosquito populations can increase rapidly, and, depending on flooding and
general weather conditions, mosquito control agencies cannot always keep up with
mosquito problems in all areas. Very often, residents can help significantly by
controlling mosquitoes around their homes and properties.
Mosquitoes Need Water: All mosquitoes have four stages of development-egg,
larva, pupa, and adult-and spend their larval and pupal stages in water. The
females of some mosquito species deposit eggs on moist surfaces, such as mud or
fallen leaves, that may be near water but dry. Later, rain or high tides reflood
these surfaces and stimulate the eggs to hatch into larvae. The females of other
species deposit their eggs directly on the surface of still water in such places
as ditches, street catch basins, tire tracks, streams that are drying up, and
fields or excavations that hold water for some time. This water is often
stagnant and close to the home in discarded tires, ornamental pools, unused
wading and swimming pools, tin cans, bird baths, plant saucers, and even gutters
and flat roofs. The eggs deposited on such waters soon hatch into larvae. In the
hot summer months, larvae grow rapidly, become pupae, and emerge one week later
as flying adult mosquitoes. A few important spring species have only one
generation per year. However, most species have many generations per year, and
their rapid increase in numbers becomes a problem.
Only the Female Can Bite: When adult mosquitoes emerge from the aquatic stages,
they mate, and the female seeks a blood meal to obtain the protein necessary for
the development of her eggs. The females of a few species may produce a first
batch of eggs without this first blood meal. After a blood meal is digested and
the eggs are laid, the female mosquito again seeks a blood meal to produce a
second batch of eggs. Depending on her stamina and the weather, she may repeat
this process many times without mating again. The male mosquito does not take a
blood meal, but may feed on plant nectar. He lives for only a short time after
mating.
Winter Survival Is Important: Most mosquito species survive the ,inter, or overwinter, in the egg stage, awaiting the spring thaw, when waters warm and the
eggs hatch. A few important species spend the winter as adult, mated females,
resting in protected, cool locations, such as cellars, sewers, crawl spaces, and
well pits. With warm spring days, these females seek a blood meal and begin the
cycle again. Only a few species can overwinter as larvae.
Mosquitoes Can Transmit Disease:
Mosquito-borne diseases, such as malaria and
yellow fever, have plagued civilization for thousands of years. Organized
mosquito control in the United States has greatly reduced the incidence of these
diseases. However, there are still a few diseases that mosquitoes can transmit, including Eastern Equine Encephalitis and St. Louis Encephalitis.
The frequency and extent of these diseases depend on a complex series of
factors.
Mosquito control agencies and health departments cooperate in being aware of
these factors and reducing the chance of disease. It is important to recognize
that young adult female mosquitoes taking their first blood meal do not transmit
diseases. It is instead the older female, if she has picked up a disease
organism in her first blood meal, can then transmit the disease during the
second blood meal. This is also true for the mosquito transmitted disease in
pets.
You Can Reduce Mosquito Annoyance: When mosquitoes are numerous and interfere
with living, recreation, and work, you can se the various measures described in
the following paragraphs to reduce their annoyance, depending on location and
conditions.
Reduce the Amount of Standing Water: The most efficient method of controlling
mosquitoes is by reducing the availability of water suitable for larval and pupal growth. Large lakes, ponds, and streams that have waves, contain
mosquito-eating fish, and lack aquatic vegetation around their edges do not
contain mosquitoes; mosquitoes thrive in smaller bodies of water in protected
places. Examine your home and neighborhood and take the following precautions:
Dispose of unwanted tin cans and tires.
Clean clogged roof gutters and drain flat roofs.
Flush sump-pump pits weekly.
Stock ornamental pools with fish.
Change water in birdbaths, fountains, and troughs twice a week.
Clean and chlorinate swimming pools; when not regularly used, they should be
emptied.
Turn over unused wading pools and other containers that tend to collect
rainwater.
Cover containers tightly with window screen or plastic when storing rainwater
for garden use during drought periods.
If mosquito breeding is extensive in such areas as woodland pools or roadside
ditches, the problem may be too great for individual residents. In such cases,
call the organized mosquito control agency in your area. These agencies have
highly trained personnel who can deal with the problem effectively.
Use Insecticides Safely:
Several commercially available insecticides can be
effective in controlling larval and adult mosquitoes. These chemicals are
considered sufficiently safe for use by the public. Select a product whose label
states that the material is effective against mosquito larvae or adults. For
safe and effective use, follow the instructions for applying the material. The
label lists those insects that the Environmental Protection Agency (EPA) agrees
are effectively controlled by the product. Read the label.
For use against adult mosquitoes, some liquid insecticides can be mixed
according to direction and sprayed lightly on building foundations, hedges, low
shrubbery, ground covers, and grasses. Do not overapply liquid insecticides -
excess spray dips from the sprayed surfaces to the ground, here it is
ineffective. The purpose of such sprays is to leave a fine deposit of
insecticide on surfaces where mosquitoes rest. Such sprays are not effective for
more than one or two days.
Some insecticides are available as premixed products or aerosol cans. These
devices spray the insecticide as very small aerosol droplets that remain
floating in the air and hit the flying mosquitoes. Apply the sprays upwind, so
the droplets drift through the area here mosquito control is desired. Rather
than applying too much of these aerosols initially, it is more practical to
apply them briefly but periodically, thereby eliminating those mosquitoes that
recently flew into the area.
Repellents Can Offer Relief: Various
commercially available repellents can be purchased as creams, lotions, or in
pressurized cans and applied to the skin and clothing. Some manufacturers also
offer clothing impregnated with repellents; coarse, repellent-bearing particles
to be scattered on the ground; and candles whose wicks can be lit to release a
repellent chemical. The effectiveness of all repellents varies from location to
location, from person to person, and from mosquito to mosquito. Repellents can
be especially effective in recreation areas, where mosquito control may not be
conducted. All repellents should be used according to instruction.
What Attracts Mosquitoes?:
Mosquitoes are attracted by perspiration, warmth,
body odor, carbon dioxide, and light. Mosquito control agencies use some of
these attractants to help determine the relative number of adult mosquitoes in
an area. Several devices are sold that are supposed to attract, trap, and
destroy mosquitoes and other flying insects. However, if these devices are
attractive to mosquitoes, they probably attract more mosquitoes into the area
and may, therefore, increase rather than decrease mosquito annoyance.
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