Insecticides for Indoor Use


Insecticides should be used indoors only as a last resort and as a complement to available nonchemical methods, such as sanitation, exclusion and mechanical disposal. The only insecticides residents should use indoors are ready–to–use sprays, dusts, or baits specifically marketed for in-home use.

Ready–to–use products are applied as they come from the container or packaging with no further mixing, dilution or modification. There are no insecticide concentrates a homeowner should use indoors by mixing with water in a sprayer. Do not use lawn and garden liquid concentrate insecticides indoors.

Numerous companies distribute ready-to-use household insecticides. There are more product names than can be listed here. When choosing an insecticides for use indoors, carefully read the product label. Look for instructions on how to apply indoors. Check to see that your pest is listed. Read and follow pesticide label directions carefully. Store pesticides only in the original container and out of reach of children and pets.

Apply dusts and baits only in areas that are inaccessible to children and pets. Keep children and pets out of sprayed areas until the spray has dried and the room aired. Do not use insecticides in any way that might contaminate food or food handling surfaces.

Insecticides can be classified as residual or non–residual, a general indication of how long the insecticide will remain active after it has been applied.

Residual insecticides persist for several hours to several weeks and are used for accidental invaders and household residents such as ants, cockroaches and fleas. Residual insecticides may come as sprays, dusts or baits. In most cases the label will state that the product controls pests on contact and for several days or weeks after application. Residual insecticide products will probably contain one of the following active ingredients: allethrin, bifenthrin, boric acid, cyfluthrin, cypermethrin, d-limonene, deltamethrin, diatomaceous earth, esfenvalerate, fipronil, hydroprene, lambda-cyhalothrin, methoprene, permethrin, Prallethrin, pyrethrin, resmethrin, sumithrin, tetramethrin, or Tralomethrin.

Non–residual insecticides are effective only during the time of treatment. They are applied as a space spray (fog) to control exposed flying and crawling insects or they may be used directly on individual pests as a contact treatment. Non-residual products usually have pyrethrin as the active ingredient.

Available Types


Household insecticide sprays are applied as liquids. They may come in an aerosol can or a trigger pump spray applicator. Liquid sprays may be residual or non-residual and are easy to use and apply. “Bombs” are a type of liquid spray. Bombs, also known as total release aerosol sprays, discharge the entire contents of the container in a single application. “Bombs” are effective at controlling exposed insects in the residence. Bombs are not effective at controlling insects, such as boxelder bugs and Asian lady beetles that are hiding in walls and attics.


Dust insecticides are a very fine powder that must be evenly spread in a thin layer or injected into voids and insect hiding places to be effective. Some dust products come in plastic squeeze bottles that also function as the applicator. Small hand dusters are sometimes available in hardware stores or you may substitute an empty, dry plastic squeeze bottle that has a small spout or opening (for example, detergent bottles). Dusts leave visible deposits which may be considered unsightly unless care and patience are used to do a tidy application. Dust insecticides are most effective when carefully applied to cracks, crevices and other pest hiding areas. All efforts to apply insecticides into concealed areas where pests hide make the application more effective, and also lessen insecticide exposure to people and pets. Boric acid and diatomaceous earth are commonly found in household insecticidal dusts.

Liquid & Station Baits

Baits are used primarily in cockroach and ant control. Bait insecticides must be eaten by the pest to be effective. Therefore, baits contain a food or other attractant plus an active ingredient. Baits must be carefully placed so the insects will encounter the bait. Sanitation is important when using baits; available food lessens the attractiveness of the bait. Be sure to use the amount of bait recommended by the manufacturer. Baits can be an effective way to control ants and cockroaches because the pest insect is attracted to the insecticide, consumes it, and transports it back to colonies or harborages. Baits also confine the insecticide in a small area, so there is less risk of exposure. Common active ingredients in baits include avermectins, boric acid, fipronil, hydramethylnon, sulfluramid and others. Be sure to place baits where they will not be encountered and tampered with by children or pets.

Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Yard and Garden, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on September 1, 2016. The information contained within may not be the most current and accurate depending on when it is accessed.