Download SAGINAW COUNTY MOSQUITO ABATEMENT COMMISSION

SAGINAW COUNTY MOSQUITO
ABATEMENT COMMISSION
Reduce Mosquito Annoyance With Awareness
Saginaw County Mosquito Abatement
Commission (SCMAC) has been controlling
nuisance and disease vectoring mosquitoes since
1977. SCMAC utilizes a fully Integrated Pest
Management (IPM) approach to reduce mosquito
populations. This includes disease and mosquito
surveillance, larviciding and adulticiding, source
reduction, and public education programs. The more
information we have about these pesky bugs, the
greater our chances of decreasing their numbers in
our community. Knowledge of the different species
of mosquitoes found in Michigan and their habitat is
essential if they are to be successfully controlled
using IPM.
The bite of a female mosquito may cause a
short-term itching sensation in the skin. This is due
to the fact that before taking her blood meal, the
female mosquito injects her victim with an enzyme.
This enzyme helps prevent blood clotting, but is
also the way all mosquito vectored diseases are
transmitted.
The introduction of this foreign
substance into our skin can also lead to inflamation,
allergic reactions, and secondary infections at the
site of the bite. Contrary to popular belief, female
mosquitoes will take several blood meals during
their life.
Large
populations
of
mosquitoes can impact businesses
such as golf courses, recreation sites,
and tourist attractions. Outdoor
recreation facilities may suffer
economic loss if their guests shorten
their stay due to mosquito annoyance.
Michigan has approximately 60 species of
mosquitoes comprising five major groups: spring
floodwater mosquitoes, summer floodwater
mosquitoes, container mosquitoes, summer Culex,
and marsh/permanent water mosquitoes.
Spring floodwater mosquitoes deposit their eggs
on damp earth in shallow depressions in wood lots
during the summer months. These eggs will hatch
the following March when the area is flooded by
melting snow and spring rain. The larvae of these
species develop slowly due to the low water
temperatures at this time of year and will emerge as
adults in early May.
They are vectors for
encephalitis and heartworm.
Summer floodwater species, Aedes vexans,
Ochlerotatus trivittatus, and Ochlerotatus sticticus,
make up the most common pest mosquitoes in
Michigan. Larvae of these mosquitoes hatch during
the summer in shallow flooded areas. Some of
these areas could be meadows, roadside ditches, tire
tracks, animal hoof prints, flood plains, and other
habitats. The larvae develop very quickly (7-10
days) and several generations may occur each
summer depending on frequency and intensity of
rainfall. They are vectors for encephalitis and
heartworm disease.
Container breeding mosquitoes
such as the Ochlerotatus triseriatus and
the Culex pipiens and Culex restuans
will raise multiple generations of mosquitoes in
unlikely places such as a child’s wading pool and
toys, old tires, tarps, and flower pot water
reservoirs. They vector encephalitis and heartworm
disease.
Summer Culex habitat varies widely but is
usually water of high organic content such as
ditches, sewage lagoons, and catch basins. Summer
Culex are vectors of encephalitis.
Marsh/permanent water mosquitoes such
as the Anopheles and Coquillettidia like clean
partially shaded water.
These are the only
mosquitoes which breed in habitat that stays wet
year round. They are the primary vector for
malaria.
Today mosquito control agencies use a
variety of methods to reduce mosquito populations.
SCMAC carefully considers the biology of the
mosquitoes that are causing nuisance problems or
disease threats. In all cases, larval mosquito control
needs to be considered as the first option for
mosquito control. Through control of mosquito
larvae, adult mosquitoes may never become a
problem. SCMAC uses source reduction (the
permanent elimination of mosquito breeding
habitats), Bti and Bs (naturally occurring larvicides),
and public education as the first choice for mosquito
prevention. Even the most rigorous larviciding
program may not be able to keep adult mosquito
populations at acceptable levels, so we must
adulticide as well. Controlling adult mosquitoes
invariably involves the use of insecticides.
of the California group of
encephalitis occur in Michigan.
West Nile virus was first detected in
Michigan in 2001. The viruses that
cause these diseases are transmitted by different
species of mosquitoes. These viruses can also infect
various kinds of wild birds and mammals. Although
mosquito-borne encephalitis is not common
annually, it may occur in epidemics in certain years.
Natural predators are often cited in
newspapers and magazines as a means for
controlling mosquitoes. However, scientific studies
have shown that bats, swallows, purple martins,
dragonflies, and other natural predators have only a
limited effectiveness, even though these methods
might sound appealing. Predation is a natural
process that is ongoing, yet we still have
mosquitoes, often in large numbers.
In August 1997, a man from Saginaw
County died of EEE viral infection. The first
Michigan resident to die of EEE was a 10-year old
boy in 1980. In 1991, approximately 60 horses in
11 southern counties died of this disease as did
hundreds of pheasants on game farms. Two
humans were ill from this disease in that year,
experiencing coma and other serious conditions. In
1993, approximately 14 equines died from EEE,
two Michigan residents contracted this disease and
one died. In 1994, another outbreak of EEE
occurred in southern Michigan, and 22 horses
contracted the disease (all died), and at least two
different pheasant flocks were affected.
Listed below are some prevention methods
that many people use to control mosquitoes in their
homes. These methods are not as effective as one
might think.
™ Bug zappers hung outside with ultraviolet lights,
actually kill more beneficial insects than
mosquitoes.
™ “Mosquito Plants” do not effectively repel
mosquitoes and are not recommended for this
purpose despite advertisements.
™ Other devices such as those advertised to repel
mosquitoes by high frequency sound are also
ineffective.
Mosquito-borne diseases do occur in
Michigan.
At one time malaria (carried by
Anopheles mosquitoes) was common in Michigan,
but now is rare. Heartworm disease is common in
Michigan and is transmitted by a variety of
Ochlerotatus mosquitoes. Prophylatic drugs are
available from veterinarians to prevent
dogs from contracting this disease. St.
Louis encephalitis (SLE), Eastern equine
encephalitis (EEE), and different types
There remains a true concern for human and
animal health. For example, in 1975 an epidemic of
SLE resulted in 93 human cases and four deaths in
Michigan, mainly in the southeastern part of the
state. EEE has occurred in outbreaks in 1942-43,
1973-75, 1980-83, 1991, 1993-94, and 1997 in
Michigan.
With knowledge of mosquito habitat you
can take significant strides towards reducing
mosquito populations in your own backyard.
Together we can make our outdoor activities more
enjoyable during the spring and summer months.
SCMAC has reference materials available
upon request as well as an educational program that
is free of charge to all Saginaw County schools,
youth groups and community organizations. Feel
free to call our agency or visit us at the address
below.
Saginaw County Mosquito
Abatement Commission
211 Congress
Saginaw, MI 48602
Phone: (989) 755-5751
Fax: (989) 758-2309
Recorder: (989) 755-0449
Web site: www.scmac.org