Bedbugs (Cimex lectularius) aren’t just found in beds; in fact, if they were, they’d be much easier to control. Bedbugs leave the bed for other locations in the room, including other bedroom furniture, cracks in boards, crevices behind light switches and baseboards, dark recesses of carpets, the backs of curtains and anywhere else they can hide in the dark. A recent study found that almost half of the bugs in a bedbug infestation may be in places other than the bed or sofa (Wang et al, 570).
Though their tendency to wander makes bedbugs hard to get rid of, their need to return to the bed to feed provides a means of detecting them easily, even when they are present in very low numbers. When symptoms of bedbugs are the only evidence they're there, a bedbug trap can help.
How to Make a Bedbug Trap
People have been making their own bedbug traps for generations: containers of liquid placed under the bed legs form a barrier to bugs moving on and off the bed, and with any luck, bugs drown in the liquid and are eliminated. Wang and colleagues used a modification of this design in their study (p. 567). To make a version of their bedbug trap:
- Find two plastic bowls that fit one inside the other, with space between. Most beds will require four pairs of bowls.
- Cover the outside of the larger bowl by gluing on rough fabric or paper so that bedbugs will be able to crawl up the plastic.
- Place the smaller bowl inside the larger bowl.
- Pour liquid into the larger bowl until it is deep enough for a bug to get caught in and drown (1 to 2 centimeters deep should suffice).
- Add a mixture of half and half talcum powder and diatomaceous earth (sometimes called insect dust, available at many garden centers) to the small bowl.
- Place the bowls under bed legs.
The researchers used ethylene glycol (antifreeze) in the larger bowl; however, this might not be a good idea if there are pets or small children in the home. Ethylene glycol has a sweet taste and is attractive to animals, but it is toxic. A safer alternative would be ethyl alcohol, which is less attractive and less toxic, though even this should be kept out of reach of children and animals. If safety is a major concern, use water.
How the Bedbug Trap Works
The bedbug trap described above is designed to trap bedbugs moving off the bed in the smaller bowl, and those moving onto the bed in the larger bowl. The liquid in the larger bowl traps, and ideally drowns, the insects. The powder in the smaller bowl won’t damage the bed legs as liquid would: the talcum powder makes it more difficult for bugs to climb out, especially up the smooth inner surface, and the diatomaceous earth will kill some or all of the bugs that come in contact with it. The double bowls also provide an extra level of security against bedbugs escaping after they fall into either trap.
This type of bedbug trap works best if there are no other routes on and off the bed for bugs. Sheets, comforters etc. should not drape to the floor, headboards should be well away from walls, baseboards, curtains, and anything else that might provide a bridge from the room to the bed.
The researchers found that bedbugs turned up in the bedbug traps even when a careful inspection of the premises revealed no bedbugs, suggesting that these traps are an effective way of identifying infestations where the bugs are rare. The traps will also protect a bed that is free of bedbugs from bugs present in the rest of the room, and kill significant numbers of bugs as they attempt to travel to (or from) the bed.
Other Bedbug Traps
Ingenious people around the world have devised other types of bedbug traps. Woven basketry or a wicker panel, placed in or adjacent to the bed provides choice hiding places for bedbugs. In the morning, the panel can be steamed or placed in hot water, or otherwise disinfected to kill the bugs. Similarly, some people have used plant leaves covered with Velcro-like hairs to trap and control bedbugs.
More recently, people have designed mattress covers and pillow covers that will effectively keep bedbugs in the mattress or pillow, or prevent them from infesting it if they are not already there. Various other products, including suitcase liners, aim to prevent bedbugs from moving from place to place with travelers.
Sources
"Bedbugs – Back From the Brink." Boase, Clive. Pesticide Outlook; Aug 2001, 159-162
"Evaluation of Two Least Toxic Integrated Pest Management Programs for Managing Bed Bugs (Heteroptera: Cimicidae) With Discussion of a Bed Bug Intercepting Device." Wang, Changlu, Timothy Gibb, and Gary W. Bennett. Journal of Medical Entomology. 46 (3), 2009. 566-71.
Rosemary Drisdelle - Rosemary Drisdelle has been published many times as a nonfiction writer and several times as a poet. Her first book, Parasites: Tales of ...
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