Using Malathion to Eradicate the Boll Weevil
in Tennessee
Plant Protection & Quarantine
December 2002
Q: What is malathion?
A: Malathion is a commonly used home, garden, and orchard organophosphate
insecticide. It is one of the safest pesticides available. There are
many uses for malathion, including agricultural and human health uses.
In an agricultural setting, malathion is used to eliminate pests, like
boll weevils and fruit flies, that threaten the productivity of important
crops like cotton and citrus. In urban areas, malathion is used to control
mosquitoes that can carry West Nile virus and other diseases of public
health importance. Malathion is also used as an insecticide to control
pests in homes and personal gardens. In addition to taking care of agricultural
pests, malathion is approved by the U.S. Food and Drug Administration
as a prescription drug for the treatment of head lice on humans.
Q: Why is malathion used to eradicate the boll weevil?
A: Prior to the formation of the Southeastern Boll Weevil Eradication
Foundation, farmers had their own methods of chemical treatment to counteract
the destructive boll weevil. Many of these methods were much less environmentally
friendly than malathion and less effective. Without a total eradication
plan that encompassed all fields, farmers worked individually to control
the pest, treating their fields multiple times each season, only to
do the same thing again year after year.
One of the main goals of the eradication foundation is to reduce the
continual use of these potent pesticides. The end result of the foundation’s
efforts will be a drastic reduction in the use of pesticides by cotton
farmers. In other states that have already eradicated the boll weevil,
pesticide use has dropped by as much as 40 to 90 percent.
Without the help of the boll weevil eradication foundation, farmers
would have no choice but to revert back to their previous ways in order
to protect their cotton crop and their livelihood. This is why the majority
of the region’s farmers voted to fund the foundation’s eradication
efforts beginning in 2000.
Q: How much malathion is used?
A: The amount of malathion needed to effectively kill the boll
weevil is very small. Only ten ounces of malathion are used for every
acre that is treated. That’s like taking one can of soda and evenly
distributing it over an entire acre.
Q: How is the malathion applied?
A: Both aerial and ground applications of malathion may be
used depending on the size and location of the cotton fields. Aerial
application are performed with fixed-wing aircraft and some helicopters.
Ground applications involve the use of tractors or all-terrain vehicles
mounted with automatic sprayers controlled by the driver. The malathion
is released at an ultra low volume, creating a mist that blankets each
field.
The boll weevil eradication program uses careful precision to apply
malathion to cotton fields. Because of application techniques and the
rural location of the cotton fields, human exposure is greatly reduced.
Unlike other eradication programs which spray entire areas, the boll
weevil foundation only targets cotton fields, further minimizing human
exposure. Some residents living next to cotton fields, however, may
experience drift. The Southeastern Boll Weevil Eradication Foundation
in Tennessee is committed to working with homeowners who have questions
or concerns about malathion drift or exposure.
Q: How often does the eradication foundation plan to spray
each cotton field?
A: It takes about three seasons to eradicate the boll weevil.
During the first season all fields are treated on a regular basis in
order to kill as many of the pests as possible before winter. The first
killing frost usually marks the end of treatment for the season.
After the first season, spraying is limited only to fields where infestations
are detected. Traps are used to determine whether boll weevils are present
in each field. The number of times each field is treated depends on
whether additional boll weevils are found following malathion treatments.
On average, fields are treated about seven times during the second season.
If all goes as planned, by the third season eradication should be almost
complete. Spraying will occur only in fields where the boll weevil continues
to be detected. The use of malathion should be minimal considering most
fields should already be free of the boll weevil. At the end of the
third season, the foundation’s eradication efforts should be successful
and cotton growers will begin experiencing better yields, and their
land value will increase.
Q: Why does the program use airplanes to treat the cotton fields?
A: In order to successfully eradicate the boll weevil, hundreds
of thousands of acres of cotton fields must be treated with malathion.
It’s not feasible to conduct such an extensive eradication program
without aerial spraying. Crop dusters are capable of treating fields
much more efficiently and just as effectively as ground units. Without
crop dusters, the boll weevil eradication program would last longer
and cost more money. Helicopters are also effective, but there are not
enough in the area to fully support the program or replace the use of
planes.
While some people are frightened by the noise from the planes, the
sound does serve to notify nearby residents that spraying is taking
place.
Q: How are aerial applicators hired?
A: The Southeastern Boll Weevil Eradication Foundation, consisting
of cotton representative from North and South Carolina, Virginia, Alabama,
Georgia, Florida, Mississippi, and Tennessee, solicits bids for aerial
application of pesticides. Bids are reviewed by program management,
and contracts are awarded by the Foundation on a competitive basis.
All applicators must meet State requirements for certification.
Q: What precautions are taken to avoid spraying houses, businesses,
and other public buildings next to cotton fields?
A: The Southeastern Boll Weevil Eradication Foundation uses
guidance technology and satellite mapping to ensure that only cotton
fields are treated with malathion. Crop dusters are trained to fly with
precision and spray fields targeted for boll weevil eradication. Satellite
tracking enables the foundation to print out the flight patterns of
every plane used by the eradication program. This information can be
helpful if there is ever a question about whether a plane sprayed beyond
the boundaries of a cotton field.
Extreme care is taken to ensure that schools, hospitals, and other
sensitive locations are identified before any spraying takes place.
When the cotton fields that surround these buildings are treated, ground
equipment is frequently used in order to keep any potential drift to
a minimum. Spraying does not occur while children are in school or after
school activities are taking place.
In addition, the foundation’s aerial and ground sprayers always
adhere to strict rules regarding weather conditions in order to limit
malathion drift from the cotton fields to nearby homes and buildings.
If the wind blows above 10 mph, all spraying is put on hold until the
winds die down.
Q: Is it okay to be outside when malathion is being sprayed
on nearby cotton fields.
A: The foundation recommends that people who live next to cotton
fields remain indoors during spraying in order to avoid any possible
drift. If you have questions about when the fields near your house will
be sprayed, call 901-772-8763 and someone from the program should be
able to give you a general time frame when the cotton will be treated,
so that you can make plans to stay inside or go somewhere else. Changing
weather conditions, however, may affect spray times, so it may be necessary
for the foundation to adjust its spray schedules.
Q: What will happen if I’m exposed to malathion while
the foundation is spraying nearby fields.
A: Because the foundation is treating only cotton fields with
malathion, it is unlikely anyone should come into direct contact with
the pesticide.
Many people exposed to malathion experience no reaction at all. As
mentioned before, it’s frequently used in the home and garden
as an insecticide. Some people, however, may experience minor irritation.
Symptoms will generally clear within an hour or two once exposure stops,
and will cause no residual effects.
To prevent such exposure, people should avoid being out of doors in
the immediate spraying area for about 30to 60 minutes after the spraying
takes place. Residents immediately adjacent to an area where spraying
is taking place may want to keep doors and windows closed during the
spraying.
Studies of laboratory animals show some suggestive evidence that malathion
may be carcinogenic at extremely high doses over extended periods of
time. These levels are thousands of times higher than a person would
ever encounter even if they stood in a cotton field and were sprayed
directly with malathion each time the field was treated.
Q: How does malathion affect people with allergies, asthma,
or other special health problems?
A: Malathion may exacerbate these conditions. If you’re
concerned, please contact your doctor or a health professional.
Q: Is the spray harmful to pets?
A: The foundation recommends that pets be kept inside while
spraying occurs. Pets that are exposed to malathion drift, should not
experience any residual effects. If you think your pet may have come
into contact with malathion after walking through wet vegetation following
a treatment, give them a bath to wash away the chemical.
Malathion can be toxic to fish. If your fish pond sits next to a cotton
field, the foundation recommends covering it, especially if the pond
is less than three-feet deep. Such ponds should be uncovered shortly
after the aerial application to prevent oxygen starvation.
Q: What if malathion gets in my backyard swimming pool?
A: Malathion for boll weevil eradication is applied directly
to cotton fields, not to swimming pools. But should drifting malathion
enter a shallow pool there would be little health risk to swimmers.
If a shallow pool ( 2 feet or less) was accidently sprayed directly
with malathion during an aerial boll weevil application, as a precaution,
people should avoid swimming in the pool for 24 hours. If a pool is
deeper, the risk decreases greatly and swimming can commence sooner.
If you are concerned that malathion has drifted into your pool, call
the eradication foundation. Environmental monitoring specialists can
place dye cards next to your pool prior to the next treatment to determine
whether malathion drift is entering your pool. If no spots are visible
on the cards, malathion has not drifted into your pool. If spots do
appear, the dye cards can be analyzed to determine the amount of drifted
malathion and ensure that it is far below any level of concern.
Q: How long will malathion residue remain in yards.
A: Residues from applications of malathion are short-lived.
The malathion should dry on grass, vegetation, and other outdoor surfaces
within two hours. On especially humid days, it may take longer for malathion
to dissipate. As a precaution, you can use a hose to wash off all outdoor
household article, including swing sets and picnic tables following
treatments. To further reduce any risk of exposure, wear shoes and socks
if you live near a cotton field and plan to be outside following a treatment.
Q: Is it safe to eat food from my garden if I live next to
a cotton field that’s being treated?
A: Yes. Malathion is a commonly used home and garden insecticide.
As with any produce, of course, it’s important to throughly wash
your fruit and vegetables before serving. If you’re concerned
about exposure, samples can be taken from your garden and tested for
malathion.
Q: Who can I contact for more information?
A: If you have questions about the program, please call the
Southeastern Boll Weevil Eradication Foundation at 901-772-8763.
The U.S. Department of Agriculture (USDA) prohibits discrimination
in all its programs and activities on the basis of race, color, national
origin, sex, religion, age, disability, political beliefs, sexual orientation,
or marital or family status. (Not all prohibited bases apply to
all programs.) Persons with disabilities who require alternative
means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600
(voice and TDD).
To file a complaint of discrimination, write USDA, Director, Office
of Civil Rights, Room 326-W, Whitten Building, 1400 Independence Avenue,
SW, Washington, DC 20250-9410 or call (202) 720-5964 (voice and TDD).
USDA is an equal opportunity provider and employer.
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