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Home Maintenance And Repair - 01500536

Using Insecticides

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 (S)
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 emulsifiable concentrates.

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 (D)
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.

Special Formulations
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.

Application Equipment
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 wettable powder.

Quart-sized Sprayer
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.

Bulb Duster
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 objectionable odors.

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 or company.

MSU is an affirmative-action, equal-opportunity 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.

This information.was reviewed as of June 2008.  For more information about the contents please contact for webpage problems .