PMPs: Get to know your bed bug monitors

By |  May 25, 2017

⦁ Active monitors are meant to attract, whereas passive monitors simply wait.
⦁ Choose monitors to fit the needs of each account.

A pair of bed bug adults find themselves stuck in a monitor. Photo: Mark Sheperdigian, BCE

A pair of bed bug adults find themselves stuck in a monitor.
Photo: Mark Sheperdigian, BCE

Controlling bed bugs (Cimex lectularius) is always easier when you know where they are. Monitors can be a powerful tool for catching bed bugs before they get out of hand. Not all monitors are created equal, so choose the proper monitor for your situation.

Most monitors have either sticky surfaces or pitfalls (featuring a slippery-sided pit). Among both types, some are active monitors and have an attractant whereas others are passive monitors and simply wait for passing bugs.

If it is known where the bugs are, no monitors are needed. When the harborage is not known, active monitors will catch bugs seeking a meal. When it’s a matter of watching for incoming bugs, passive monitors can fit the bill.

Attractant options

There has been a lot of research on bed bug behavior already, but there is still much to learn. It is known, for example, that carbon dioxide (CO2) has a dramatic effect on movement and results in improved trap catch for all types of monitors when bugs are present. Still in question, however, is the exact nature of the effect CO2 has on the bugs. Does it attract them from long distances? Short distances? Does it even attract them, or simply cause them to move? We await research results with bated breath.

Bed bug monitors. Photo: Mark Sheperdigian, BCE

Bed bug monitors.
Photo: Mark Sheperdigian, BCE

Monitors may feature several different types of attractants. Besides CO2, common ones include heat, human odors (known as kairomones) and bed bug odors (pheromones). These monitors will often need to outcompete the sleeping or sitting occupant, but they can be helpful in locating bugs that could not otherwise be identified by visual searches.

Standing guard

Using monitors to watch for bed bugs coming in is different than when an active infestation exists. Place monitors between likely areas of entry and likely harborage such as beds and couches. Some passive monitors are designed to be placed under bed legs or chair legs, and will capture bugs that are heading either to the leg or from it.

Some interceptors feature both an inner and an outer well. Trapped bugs in the outer well indicates they headed to the leg, whereas those trapped in the inner well were likely coming from the leg.

In carpeted areas, the weight of the leg may crack the monitor. Fix this by placing a flat wooden square under the monitor. This will not affect the functioning of the monitor. These monitors, also known as interceptors, also can be placed near furniture legs or in corners where they will capture bugs as they move through. This often is an effective solution when the account is high-risk for bugs being brought in.

The key to bed bug control is early detection. Monitors can play a valuable role — if you know how to best use them.

Contributor Mark Sheperdigian can be reached at

This article is tagged with and posted in Bed Bugs, featured, Technical

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