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Extension > Garden > Insects > Prevention and control of bed bugs in residences

Prevention and control of bed bugs in residences

Dr. Stephen A. Kells, Assistant Professor
Jeff Hahn, Extension Professor
Department of Entomology
University of Minnesota

Adult bed bug

Bed bugs, Cimex lectularius, have resurged to quickly become a very important pest of the 21st century, as they invade numerous urban areas. Our society has had a 30+ year "vacation" from this pest, when bed bugs were almost completely removed from North America as a result of mass treatments with older types of insecticides (DDT, Chlordane, Lindane). Recently though, bed bugs have found ample opportunity to increase in numbers and spread through society. Their success is a result of a combination of factors: increased travel of people; improved treatment methods that specifically target other insect pests (and thus not impact bed bugs); and the lack of public awareness. In addition to homes and hotels, bed bugs are also being found in schools, retail facilities, office buildings, libraries, and other public areas.

Why are they important?

Bed bugs are parasites that feed on the blood of people, using these blood meals to grow and reproduce. They do not distinguish between dirty or clean homes and all people are vulnerable to infestations in their homes. Bed bugs are also capable of feeding on animals, including dogs, cats, and other pets.

They live close to areas where people typically sleep, rest, or sit for long periods. Hungry bugs will move out from their hiding places, in search of exposed skin. Typically, the head and neck are bitten, but bed bugs will also bite bare arms, hands, and legs. When searching for a place to feed, these bugs can move very quickly. Once an appropriate site is found, they feed for 2-5 minutes until full, and then move quickly away from the person and into a hiding place.

In addition to bed bugs moving towards a person when they are least likely to notice the insects, the result of their bites may also go unnoticed, or can be mistaken for the bites of other pests. All people are not equally sensitive to bed bug bites, so while some victims break out in rashes from the bites, other people may not display symptoms. When a reaction does occur, the results of feeding can be mild (a simple red spot) to severe (rash or even hives). The reactions caused by feeding might be mistaken for other problems. Fleas, mosquitoes and other biting insects, sensitization to detergents and soaps, and irritants (e.g., poison ivy) are some of the conditions victims of bed bugs thought they were dealing with.

Bed bugs are not known to transmit disease to people. They have been discovered to harbor 28 different human pathogens, but fortunately, the transmission of these diseases to people has not been demonstrated.

What do they look like?

Bed bug before and after a blood meal

Adult bed bugs are oval, flattened, brown, and wingless insects approximately 1/4" to 3/8" long (5-9 mm). They are similar in appearance to a wood tick. After the bug has taken a blood meal, its color will change from brown to purplish-red. Also after feeding, it is larger and more cigar-shaped making it appear like a different insect. Young bed bugs are much smaller, 1/16" (1.6 mm) when they first hatch, and nearly colorless except after feeding, but resemble the adult in general shape. You may also find cast skins, which are empty shells of bugs as they grow from one stage to the next. After a blood meal, bed bugs deposit fecal spots (composed of digested blood) in areas adjacent to the feeding site or back at their hiding places.

What is their life cycle?

Bed bug nest

Bed bugs are active at night and generally hide during the day. After mating, females lay white, oval eggs (1/16-inch long) into cracks and crevices. An individual bed bug can lay 200-250 eggs in her lifetime. The eggs hatch in about 6-10 days and the newly emerged bed bug nymphs seek a blood meal. Immature nymphs molt five times (i.e., they shed their outer exoskeleton in order to grow) before reaching adulthood. They need to feed at least once before each molt, although they could feed as often as once a day. There may be three or more generations per year. All ages are found in a reproducing population. Immature bed bugs may live for several months without feeding while adults may survive as long as one year without a meal. Under normal circumstances, adult bed bugs will live for about ten to eleven months.

Bat bugs

Bat bugs have longer hairs near their heads.

Another bed bug species that can be found in homes is the bat bug, Cimex adjunctus. They can be common, but they are not encountered as often as bed bugs. Even when they are present in a home, they are reported to bite people much less frequently. Bat bugs can be identified by the longer hairs along the lateral edges near the head. We recommend that you have a specialist examine the sample for proper identification. Bat bugs live in attics and eaves associated with bats, so inspection and control measures must be expanded to include areas where they (bats) may be found.

Less frequently encountered bed bugs

There are other species of bed bugs that may be encountered in Minnesota. The chimney swift bug, Cimexopsis nyctalis, and the swallow bug, Oeciacus vicarius, feed primarily on birds. However, they can occasionally be pests in houses when host birds are nesting in the home (including the attic and eaves). Like bat bugs, these other species will also feed on humans when their normal hosts are absent.

How can I detect an infestation?

Bed bugs on a backpack

Bed bugs along a mattress seam

Bed bugs on the underside of a box spring

Bed bugs on a metal bed frame

Bed bugs typically cluster together in favorable harborage areas. However, some bed bugs will live by themselves, away from the rest of an infestation. The best way to determine if you have an infestation is to look for bed bugs where you sleep (or rest). In bedrooms, look particularly on and around boxsprings, mattresses, bed frames, tufts, folds, and buttons on mattresses, furniture, such as desks and chairs, behind wall paper, clocks and pictures, cracks in wood floors, and under the edge of carpet. If you travel also check your luggage, where you typically set it down when you enter your home and where you store it.

While bed bugs are most commonly found in bedrooms, infestations can also occur in other rooms, including: bathrooms; living rooms; and laundry rooms. Dark blood spots on sheets and bedding may indicate bed bug feeding. Bed bugs will sometimes excrete while they are feeding. This results in darker (dark reddish or brownish) spots or smears found on bed sheets, pillowcases and mattresses, or in nearby areas. This material is composed mostly of digested blood and the stains are very characteristic. In severe infestations, bed bugs may be more noticeable. The accumulation of bugs, cast skins and fecal spots will be very apparent upon close inspection.

Remember these insects are small (1/16" to 1/4") and very flat, so they can move into very tight corners and cracks. In some infestations, they were found under picture frames, in between the glass and the frame and behind electrical outlet and other wall plates! Be prepared to do some close inspection and when in doubt, you should consider having the inspection done by a pest control service provider.

If at any time a bed bug is found: discontinue inspection and initiate control activity! Do not continue with the inspection alone, as bed bugs will move from their hiding places once disturbed. Further inspections must be accompanied by control measures.

How can I control an infestation?

We highly recommend that you seek assistance from a professional pest control company.

Controlling an infestation requires very detailed work, much moving and disassembly of furniture, and specialty equipment. Careful inspections must be completed in conjunction with non-chemical controls (such as heat treatments, vacuuming, and steam treatments) and insecticide treatments. The insecticides available are commercial products requiring special equipment and training. The insecticides available in over-the-counter products and methods used by residents are not effective in controlling bed bugs.

Another method that pest control services use for controlling bed bugs in homes is the use of heat treatment. Specialized equipment is used to raise the temperatures in target areas to 118° F and then maintain it for at least 70 minutes. All stages of bed bugs are killed when this is done properly. While very effective, heat treatment does not prevent bed bugs from being brought back into a home and reinfesting it.

It is important to cooperate with a pest control service. However, it should not be necessary to have to move or discard your furniture and your belongings out of your home, especially from an apartment or condominium. Sometimes furniture is removed and heat treated in a container but it would be rare to actually need to throw items away.

For additional information about control measures, see Bed bug control in residences.

To find a professional belonging to the National Pest Management Association, go to the Pest World website and type in your zip code in the search box under Find a Pro.

What can I do in my home?

When working with a pest management company, there are some additional measures that you may be asked to do to help eradicate bed bugs.

Using heat

You can use your washing machine and dryer to kill bed bugs that may be infesting clothes. Clothes laundered in hot water and/or dried in temperatures hotter than 122° F for 20 minutes will kill all stages of bed bugs. This is typically the medium-high setting. If you are not sure what temperature you drier can reach, ask a professional to test it for you. You can also sterilize curtains and other fabrics, rugs, shoes, backpacks, stuffed animals, toys, and similar objects by drying them for about 30 minutes (for a full load).

Using cold

Cold temperatures can kill bed bugs if they are exposed to it long enough and at temperatures that are cold enough. If you place objects into a freezer, at 0° F all stages of bed bugs will be killed when they are left in it for 7 – 10 days.

It is a common assumption that if you put infested furniture outdoors during winter when it is cold, that the temperatures are sufficient to kill bed bugs. While you will undoubtedly kill some bed bugs, there is no guarantee that you will kill all of them. There is little research that has examined how cold and for what duration you need under those circumstances. The U.S. military believes that if you expose furniture to 0° F or less for four days or more, that may be sufficient.

Even if you put furniture outdoors at 0° F, consider that the temperature where the bed bugs are hiding may not be as cold as the air temperature. Also, any sun shining on the furniture can raise the temperature in localized areas. Although it may seem cold, the odds of the temperature remaining consistently at 0° F or less for four consecutive days are unlikely.

Although you cannot guarantee that freezing temperatures will kill all of the bed bugs infesting an object, you can use the cold to immobilize any bed bugs that are present until you decide what to do with the object.

Encasements

An encasement is a fabric covering that completely encloses a mattress or box springs. It creates a barrier to prevent bed bugs from infesting or escaping mattresses or box springs. Although the encasement can become infested themselves, the infestation is easier to detect. They are useful when you want to protect a mattress you know is free of bed bugs (it has been heat treated or you have purchased a new mattress). You can also use encasements on infested mattresses and box springs trapping the bed bugs inside them and allowing you to continue to use them as long as they are not ripped or torn. Make sure you buy encasements that are specifically designed for protecting against bed bugs. You can purchase encasements from professional pest control services or retail stores.

Bed bug interceptor

Bed bug interceptors

These are small plastic trays with an inner and outer ring. They are intended to be placed under the bed legs. Bed bugs that attempt to climb up from the floor to the bed become trapped in the outer well. Any bed bugs that try to climb down will become trapped in the center well. Bed bug interceptors not only help to reduce the number of bed bugs that can reach the bed but also acts as a monitoring tool to help determine whether bed bugs are present (if that is an issue). You can purchase Bed Bug Interceptors online (type bed bug interceptor into a search engine for sources).

Insecticides

Home residents are discouraged from attempting to treat bed bugs themselves. The insecticides available in over-the-counter products are not effective in controlling bed bugs.

Particularly bug bombs, also known as total release foggers, are popular but are not effective when treating bed bugs. These products throw insecticide into air of which very little, if any, comes in contact with bed bugs which are hiding in cracks and behind and under objects. Its use will not have any impact on a bed bug infestation. Unfortunately, it is too easy for people to misuse or over use bug bombs which can result in unnecessary pesticide exposure. Bug bombs are also potentially flammable if used incorrectly.

Although home residents are discouraged from trying to treat bed bugs themselves, if you should decide to use a pesticide, it is very important to carefully to read and understand the label before using and to follow all label directions. The product you intend to use should be labeled for bed bugs.

The greatest risk for encountering bed bugs appears to be while people are traveling. Regardless of the type of accommodations you stay at, it is a good precaution to check your room. Check around the headboard and adjacent areas of the bed. Also inspect luggage stands or other areas where suitcases are typically set down. Be aware of any unexplained bites you may find in the morning; that could be the result of bed bugs. Also watch for fecal spots, which could occur on bed sheets or nearby areas. Inspect your luggage when you get home after a trip for any bed bugs that may have escaped your earlier attention. For more information see Preventing bed bugs from hitchhiking to your home.

Other sources of bed bugs can be associated with the scavenging of used furniture. Residents and tenants are strongly cautioned against "scavenging" beds and furniture that have been discarded and left by the curb for disposal, or behind places of business. Bed bug infestations are not limited to beds and mattresses, and they can be found on tables, drawers, and even electronics if these items were located in a bedroom or other place that could support an infestation.

For more information on bed bugs, see the University of Minnesota bed bug website.

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