State University Extension
Home Maintenance And Repair - 01500536
For good insect control you must learn how to use insecticides
(chemicals) effectively. Most are available in several formulations,
each with its own use for control in and around houses.
Those discussed here are the more common formulations. The formulation
is the way in which an insecticide is packaged by the manufacturer for
sale and subsequent use by the consumer. This information is not meant
to replace detailed information given on insecticide containers; always
read the label for specific use instructions.
Emulsifiable Concentrates (EC)
Emulsifiable concentrates are liquids. They must be mixed with water,
turning it milky (the emulsion). Apply them outdoors both to plants and
around foundations. Be careful when applying to young, tender flowers
and shrubs, for they may injure these plants. In concentrated form,
emulsifiable concentrates are dangerous if spilled on clothing and
skin. Change clothing and use masks and protective clothing while
spraying, especially if applying dangerous materials over a long period
of time. Launder contaminated clothing separately, then thoroughly
rinse out the washing machine.
Solutions are also liquids. They differ from emulsions in that they are
ready to use and ARE NOT MIXED WITH WATER. They are made with refined
(deodorized) kerosene or similar materials, plus an insecticide. Use
them indoors to control household insects. Do not apply to plants, for
they cause severe injury. Solutions are dangerous if spilled on
clothing and skin. Immediately wash off with soap and water and change
clothing. Launder contaminated clothing separately, then thoroughly
rinse out washing machine. For other instructions, see emulsifiable
concentrates above. Deodorized kerosene is difficult to obtain in small
quantities today, so most liquid insecticides must be used a
Wettable Powders (WP)
These are similar to dusts (see below), but they contain a higher
percentage of chemical and are mixed with water and applied as sprays.
The spray is seldom used indoors, but is useful when applied outdoors.
Avoid breathing or getting powder (or spray) on the skin. Use masks and
protective clothing, especially if applying dangerous materials over a
long period of time.
Dusts are dry powders which normally contain a lower percentage of
insecticide than wettable powders. They are used as bought and ARE NOT
MIXED WITH WATER. Use them both indoors and outdoors as previously
specified. They are especially suited to treatment of cracks and
crevices, wall voids and other seldom disturbed areas. They loose much
of there effectiveness when exposed to moisture because of their
tendency to form lumps.
Aerosols and Foggers
Aerosols and foggers are liquids held under pressure in a container.
When released, usually by pressing a button, some form a gas, others a
spray. "Gas-producing" (space spray) types are used for control of
flying insects (such as flies). As either a total-release "bug bombs"
(foggers) or trigger controlled spray can, they are designed to clear
rooms or large number of exposed flying insects. They have no residual
action and, therefore, will not kill insects which emerge from
protected crevices or other rooms after the treatment. The liquid types
(contact residuals) are designed for insects that crawl or run on
floors (such as ants and roaches). These materials deposit a toxic
residue on surfaces where insects rest and travel and kill pests over
an extended period of time. Choose the right one to fit your needs.
Baits and Bait Traps
These are mixtures of a food bait and a poison. The bait and poison
mixture may be placed in a special bait trap, or it may be a liquid
designed to be spread on small pieces of cardboard. In either case,
place all baits in areas where they are not readily accessible by
children and pets.
Fumigants and Repellents
These are insecticides that readily vaporize into the atmosphere and
give off gases which kill or repel insects. Fumigants may be sold as
solids, liquids or in liquid-impregnated resin strips.
Some insecticides come in special formulations such as insecticide
impregnated tape or insecticidal paints. These are designed to expose
insect pests to toxic surfaces, thereby killing them.
The compressed air sprayer, the quart-sized sprayer, the aerosol can,
the paint brush and the bulb duster are probably the best kinds of
equipment for the home owner to use for applying household
insecticides. Each type of equipment has both good features and
disadvantages. Careful study of your insect control jobs will help you
buy and use the best type effectively.
Compressed Air Sprayer
The water capacity of a compressed air sprayer is usually one to four
gallons. Air is pumped into the tank, forcing the spray out when the
nozzle is opened. It is ideal for outdoor application of wettable
powders and emulsions. Its use indoors is limited if a lot of water is
applied with the insecticide. Shake the sprayer frequently when using a
The quart-sized sprayer is also a compressed air type, but air must be
pumped into it continuously while in use. It can be used satisfactorily
with emulsions and solutions, but not wettable powders. Use it both
indoors and outdoors for treating small areas. Note: where high pressure is needed
for good application, these have limited use.
Use an inexpensive paintbrush to apply insecticide solutions to
baseboards, screens, and similar areas inside buildings. A light film
is usually sufficient.
This apparatus is used for applying dusts to cracks, crevices and other
voids. The dust is placed into the bulb or bellows; squeezing the
device forces the dust out the nozzle and into the void to be treated.
A little bit of practice (with plaster or Paris of flour) will help you
perfect your dusting technique. Best results are achieved when dusts
are applied in a thin, even layer. If you can easily see the dust on a
surface you have used too much!
1. Inside buildings, apply registered residual contact to small areas
only (such as baseboards, corners, cracks and crevices, etc.). Do not
apply to entire rooms or buildings. Some insecticide formulations also
have a strong odor.
2. Avoid using any insecticide around food or where children or pets
can get into it. Do not allow children on insecticide-treated grass
until 3 days after application.
3. Avoid breathing sprays or dusts. A handkerchief fitted to the face
will help prevent excessive inhalation of these materials. If there is
a chance of breathing highly poisonous materials, use a mask. While
some insecticides such as pyrethrum or rotenone may be harmful to
persons with asthma, the chemicals are generally quite safe otherwise.
4. If emulsifiable concentrates or concentrated wettable powders are
spilled on the skin, wash immediately with soap and water. Remove
contaminated clothing immediately and launder separately. Thoroughly
rinse the washing machine after use.
5. Do not use insecticides in oil (kerosene) around open flames (pilot
lights), electrical wiring, or an asphalt floor covering. Both
oil-based and water-based insecticides which may stain or spot fabrics
and other porous surfaces.
6. Outdoors, avoid heavy applications to tender flowers and shrubs,
especially emulsions. Read labels to avoid using any material specified
as damaging to certain plants.
7. Never puncture an aerosol can. This can cause injury.
8. Read the label for each insecticide used. Then, follow directions.
Indoors, apply only those insecticides manufactured especially for this
purpose. Formulations suitable for treating livestock and plants of all
kinds outdoors ARE NOT GENERALLY the best types for use in buildings
(homes). For example: formulations for indoor application should
contain only the purified grade of the chemical, not the commercial
agricultural product. There is less objectionable odor to purified
grades than to the agricultural grade. In addition to the kind of
insecticide used in household preparations, the carrier (often an oil)
should be specifically processed (refined) to reduce or eliminate
Another point to consider: When a household pesticide is applied behind
quarter-round or any other like situation, or where there may be
excessive heat, odor from the chemicals may be more noticeable and
consequently more objectionable than the pest itself.
For a complete listing of suggested control options for all home, yard
and garden insect pests contact your local Extension Service, found
under local government in the phone book.
Read and follow instructions on the pesticide label. Heed all warnings.
Check with your physician if you have any concerns regarding your
personal health risk.
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This information is for
educational purposes only. References to commercial products or trade
names does not imply endorsement by MSU Extension or bias against those
not mentioned. This information becomes public property upon
publication and may be printed verbatim with credit to MSU Extension.
Reprinting cannot be used to endorse or advertise a commercial product
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employer. Michigan State University Extension programs and materials
are open to all without regard to race, color, national origin, gender,
gender identity, religion, age, height, weight, disability, political
beliefs, sexual orientation, marital status, family status or veteran
status. Issued in furtherance of MSU Extension work, acts of May 8 and
June 30, 1914, in cooperation with the U.S. Department of Agriculture.
Thomas G. Coon, Director, MSU Extension, East Lansing,MI 48824. This
information is for educational purposes only. Reference to commercial
products or trade names does not imply endorsement by MSU Extension or
bias against those not mentioned.
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of June 2008. For more information about the contents please
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