 
Debuzzing Mosquitoes the Natural Way
by Molly Rauch
In the
fifth century, B.C.E., when Herodotus visited Egypt, he noticed
that people slept under nets to avoid mosquitoes. More than 2,000
years later, people are still trying to elude the biting bug. With
thousands of species to their name, mosquitoes thrive worldwide.
They lay their eggs on water, so they are especially populous in
places like Key Biscayne, Florida, near the Everglades. A few
years ago Patricia Weinman, a Key Biscayne resident, experienced
how pesticides can be more harmful than the bugs themselves.
Cause for Concern
In April 1997, Weinman, eight months pregnant, went to a
neighbor's party. "We didn't hear the mosquito truck," she says.
Sent by Dade county in a routine effort to kill mosquitoes - and
not required to broadcast a warning - it was spraying malathion.
"It fogged the inside of the house," Weinman recalls. "Every
window was open." Within five minutes of the truck's passing,
Weinman threw up. Within 48 hours, six of the eight children
present developed respiratory reactions. Weinman's doctor assured
her that malathion exposure has been shown to cause birth defects
only in the first trimester, but she can't forget that the
organophosphate, related to nerve gas, is a possible carcinogen
linked to eye disorders, immune system disruptions, and genetic
damage.
In Wilmette, Illinois, the North Shore Mosquito Abatement District
(NSMAD) was regularly spraying resmethrin, a synthetic pyrethroid
that can cause asthma and skin irritation, at night. NSMAD did not
publicize its tactics or announce spray schedules, so "most people
don't know about the program," says Jack Richman who, with
concerned neighbors, told NSMAD that they wanted the routine
spraying to stop. In December 1996, NSMAD agreed to a permanent
ban.
One reason for the existence of Mosquito Abatement District (MADs)
in almost every state is that the bugs can carry diseases like
West Nile and other encephalitis viruses, dengue fever, yellow
fever, and malaria (which kills over one million people every
year). Malaria was virtually eradicated here by the 1950s, in part
through widespread use of DDT, but the threat of mosquito-borne
disease remains. Jay Feldman, executive director of Beyond
Pesticides, says, "There is a crisis orientation to mosquito
control, and it means (MADs) have gone from using organochlorines
(like DDT) to organophosphates." Organophosphates act by
interfering with the nervous systems of insects and sometimes
other species, including humans. MADs commonly use the
organophosphate pesticides malathion, naled (corrosive to the skin
and eyes), and resmethrin, a synthetic pyrethroid suspected of
disrupting hormone functions.
Integrated Pest Management
"Pesticide is the easy way out," says Gerard Ferrentino, director
of the Urban Integrated Pest Management Program at Cornell
University. Less toxic methods are more time-consuming, but they
can be just as effective because they prevent mosquitoes at the
source - in water - by killing larvae, as opposed to focusing on
adult insects.
Responsible controllers use Integrated Pest Management (IPM): They
monitor mosquito populations, target larvae, and spray only as a
last resort. To reduce larvae populations, many MADs use Bacillus
thuringiensis israelensis, or BTI, a bacteria that damages the
mosquito's stomach or the larvae. Because it targets only
mosquitoes, black flies, and some midges, BTI is considered safe
for humans and natural systems. MADs also may use natural larvae
predators, such as mosquito fish (Gambusia), stickleback, or
guppies. (MADs should carefully consider the introduction of
non-native fish species; often these fish work best in artificial
water-bodies.) Some MADs practice what John Rusmisel, district
manager of California's Alameda county MAD, calls "wetland
enhancement" - increasing water circulation and displeasing the
stagnant-water-loving mosquito. While this may alter the
environment, it's better than the old practice of draining
valuable wetlands. MADs may also use an insect growth regulator
like methoprene, which interferes with the maturation of several
insects. Methoprene is considered safe for mammals, but may harm
freshwater invertebrates.
Sometimes MADs decide they have to spray for adult mosquitoes - if
a West Nile or other encephalitis outbreak is a concern, for
example. If your neighborhood is on the hit list, "stay inside,"
advises Bill Quarles, managing editor of The IPM Practitioner, a
publication of the Bio-Integral Resource Center (BIRC), and don't
forget to bring your pets in too. "Wait for it to settle," Quarles
adds: a pesticide can be most dangerous when inhaled. Keep windows
and doors closed and the air conditioner off for as long as you
can stand it, preferably an hour.
Weinman, in Key Biscayne, convinced Dade County to strap a siren
to the spray truck. That way, people can at least reduce their
exposure. What's most important is that people are informed. "Too
often," Feldman says, "people see the trucks coming to spray, and
they don't know where the decisions are being made."
What You Can Do
- Prevent breeding: Begin around your home.
Go outdoors and look for any container that can hold water -
cans, buckets, saucers under plants, leaf-filled drains, old
tires - and remove it. Water bodies that can't be drained, like
wells and ponds, can be stocked with natural predators. Contact
your MAD to see what fish are permitted in your area.
- Prevent biting: Make sure every window,
door, and porch is fully screened, and check your screens often
for tears. Wear protective clothing or try to stay inside at
dusk, when mosquitoes are most active. Use least toxic insect
repellents - your natural foods store should have a selection.
- Contact your MAD: If you can't find your
MAD in the local government pages of the phone book, try your
local health, pest control or agriculture department, or contact
the American Mosquito Control Association. Ask your MAD what
they do and when they do it. You may request that your MAD not
spray on or near your property.
- Push for notification: If your MAD has no
way to warn people while spraying, go to their meetings and ask
them to announce their practices - on the radio, in the paper,
and/or by placing signs along their route.
- Encourage IPM: Discuss less toxic control
methods at MAD meetings. Encourage them to monitor breeding
sites and employ larvacide.
- Form a MAD: Areas without MADs are more
likely to experience fragmented, short-term, toxic mosquito
control efforts.
About the Author:
Molly Rauch
Molly Rauch is a health writer in New York.
This article was reprinted from The Green Guide newsletter, a
publication of The Green Guide Institute. Want more practical
solutions to environmental health risks in your home and
community? Subscribe online to The Green Guide at
www.thegreenguide.com.
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