Selection and Use of Household Insecticides,If Needed

Control of household insect pests is dependent upon two factors; a knowledge of the pest and its habits AND the selection of the proper management strategy, an insecticide is not your only choice. If you choose to use an insecticide it is important that you thoroughly understand their different uses, methods of application, limitations, and hazards. It is therefore important to know about the selection and safe use of household insecticides.

I. Insecticide Formulations Formulation - the way in which an insecticide is packaged by the manufacturer for sale and subsequent use by the consumer.

1. FOGGERS - these are total-release aerosol cans ("bug bombs") that generate a mist to saturate large, enclosed spaces. They are best used to clear rooms of large numbers of exposed insect pests. Use of these foggers requires preparation (remove plants, pets and food; cover furniture) and time (for fogging and ventilation after use). The insecticides used in foggers have no residual action, and therefore will not kill those insect pests that emerge from protected crevices and other rooms after the treatment. Materials used: pyrethrins plus synergists.

2. AEROSOLS - these are similar to foggers, except the cans are provided with a trigger which allows them to be used in short blasts as needed. There are two different types of aerosols:

a) Aerosol mists - these aerosols contain contact space spray insecticides designed to knockdown and kill flying insects. Materials commonly used: pyrethrin, d-trans- Allethrin or resmethrin plus synergists.

b) Aerosol sprays - these aerosols contain contact residual insecticides designed for the control of crawling insects. These materials deposit a toxic residue to surfaces where insects rest and travel, and will kill pests over an extended period of time. Materials commonly used: propoxur, chlorpyrifos, silica gel, resmethrin, or pyrethrins plus synergists.

3. LIQUIDS - these are contact residual insecticides sold in a concentrated form, and are mixed with water and applied with a hand pressurized sprayer or pump bottle. some products may come ready to use (TRU) in special squirt bottles and these are especially useful for applying the insecticide into cracks and crevices where insects hide. Materials commonly used: propoxur, chlorpyrifos, malathion, diazinon or pyrethrins plus synergists.

4. DUSTS - or powders, are used in the dry form. they are not mixed with water. These materials are easily introduced into cracks and crevices where insects hide. They lose some of their effectiveness in moist situations because of their tendency to form lumps. Materials commonly used: boric acid or propoxur.

5. BAITS and BAIT TRAPS - these are mixtures of food bait and poison. The bait and poison mixture is generally sealed in a metal can with small entrance holes for the insects to enter. In some cases the insects may take the poisoned bait back to the colony. Materials commonly used: proposur, boric acid or arsenicals.

6. TAPE - these are strips of paper coated with poison on one side and adhesive on the other. The tape is placed in areas where the insects will walk over them and come in contact with the insecticide. Materials commonly used: propoxur.

7. FUMIGANTS - these are insecticides that readily volatilize into the atmosphere and give off gases which repel or kill insect pests. Materials commonly used: paradichlorobenzene (PDB) or napthalene.

8. REPELLENTS - these are chemicals which are used to repel biting insects of man and livestock. Those products with the highest percentage of active ingredient will provide the highest degree of protection from biting pests. Materials commonly used: diethyl meta-toluamide (Deet), or dimethyl phthalate.

II. INSECTICIDE ACTIVE INGREDIENTS Synergists - these are chemicals that "activate" some insecticides and make them more poisonous to insects, thereby enhancing the effectiveness of the active ingredient. MGK 264 and piperonyl butoxide are two commonly used synergists.

HAZARDS: those insecticides which contain piperonyl butoxide should NOT be used in homes or other situations where any person is using a prescribed medication for a serious illness since this synergist effects the production of liver enzymes, thereby causing complications.

Pyrethrins (or synthetic pyrethroids - this is the name used for those synthetic insecticides which duplicate the botanical insecticide pyrethrum which is derived from Chrysanthemum cinerariaefolium. Pyrethrins are low in mammalian toxicity but quickly knock down insect pests on contact. Pyrethrins are mainly used in flying insect space sprays and they decompose rapidly in fluorescent and natural light, leaving no residue.

HAZARD: asmatics and persons sensitive to pollen should avoid inhaling pyrethrins since it may cause allergic reactions.

d-trans-allethrin - this is one of the types of synthetic pyrethrins, and is used to control flying insects, often in combination with a synergist, and has a quick knockdown effect.

resmethrin - this pyrethroid material is also used in the control of flying insect pests and is especially useful in controlling hard to kill flying insects such as bees and wasps.

chlorpyrifos - this contact residual insecticide is particularly effective against roaches. It does not kill roaches upon immediate contact, but this delayed mortality is more than compensated for by the long residual life.

propoxur - this contact residual insecticide is also effective against crawling insects, but does provide some rapid knockdown in addition to the long residual life.

diazinon - this contact residual insecticide is widely used for control of household, turf, ornamental tree, and garden insect pests. Only premium grade (label specifies indoor usage) should be used inside the home.

HAZARD: this is one of the more toxic substances available to the homeowner for control of household pests. It must be used with caution and in strict accordance to label instructions.

malathion - this is another one of the commonly used insecticides for control of pests in and around the home. It has relatively low mammalian toxicity, however, the residual life is not as long as some of the other contact residual insecticides. Only premium grade malathion should be used inside the home.

silica gel - is a nearly non-toxic material. The silica abrades (rubs off) the waxy layer on the insect cuticle, causing the insect to dehydrate and die (provided the relative humidity is low enough). High moisture will also cause the silica to lump together and lose its effectiveness.

HAZARD: inhalation of the dust may cause severe irritation.

boric acid - this material has limited use in some ant and roach baits. It is a persistent, but slow-acting, poison. Boric acid, USP, sold as an eyewash is safer to use because of the lower concentration than the insecticidal boric acid. Boric acid has been used as a roach powder, but should only be lightly dusted into cracks and crevices (NOT exposed surfaces) and SHOULD NOT be used in homes with children.

HAZARD: Boric acid is acutely poisonous if ingested, especially in infants and children.

arsenicals - these materials were once widely used as insecticides, but owing to their high mammalian toxicity they have been phased out of use. However, sodium arsenate is still used in some ant bait traps and is highly effective, but must be used with great caution.

HAZARD: HIGHLY TOXIC to all animals. Should not be used in homes with pets or children.

paradichlorobenzene (PDB) - crystals and nuggets of PDB are used as fumigants to repel or kill fabric pests like clothes moths and carpet beetles. Fabrics put into storage should be washed or dry cleaned and then stored in sealed containers with PDB to prevent clothes moth or carpet beetle damage.

HAZARD: DO NOT breathe the PDB fumes. napthalene - flakes of this material are used in the same manner as PDB.

N,N-diethyl-meta-toluamide (Deet) - is widely used as an insect repellent for mosquitoes, biting flies, gnats, no-see-ums, chiggers, ticks, and fleas. It is generally formulated with ethyl or isopropyl alcohol. Those repellents with the highest percentage of active ingredient(s) (Deet or dimethyl phthalate) will be the most effective.

HAZARD: Deet is a moderately toxic insecticide; it may cause skin rashes.

dimethyl phthalate - is another commonly used insect repellent, and is especially effective against mosquitoes, fleas and chiggers. Unlike Deet, it is a relatively non-toxic material.

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.

Tom Ellis, M.S., Department of Entomology.

MSU 2003

Selection and Use of Household Insecticides,If Needed

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