PMPs: What to do when bed bugs return


September 27, 2017

⦁ Bed bugs are highly attracted to areas with previous activity.
⦁ A new bed bug is likely to find its way to old evidence.

It can be exasperating to get a report of a fresh bite from a bed bug account that has had no bites and no sightings in a month or more. After a thorough inspection, you find one or two bugs right in the middle of the droppings, cast skins and dead bugs from the original infestation. This scenario is all too common and can cause a lot of tension between the pest management professional (PMP) and client.

The occupants had a lovely respite from the nightmare, but now “they’re back!” They suspect some bugs were missed during the treatment, but if a month has gone by without bites or sightings, this is really unlikely. For tenants who react badly to bed bug bites, a month since the last bite should indicate success. For a new bite a month or two later to be part of the original infestation, the bug would have had to voluntarily go without a meal. While they are physically capable of lasting that long, it’s unlikely — especially in an active environment with a meal readily available. As every bed bug scent detection dog handler knows, bed bugs unfed in a vial can hardly last a month; a couple weeks usually is all you get. They survive longer periods of starvation in a cool, quiet environment.

It is common for pest management companies to offer service warranties of 30, 60, and even 90 days, which may be interpreted as a de facto time period for complete success. In reality, though, two or three weeks from the initial treatment is typical for the elimination of moderate infestations.

Education is key

One way to avoid these faulty expectations is clear communication before the job begins.

A bed bug showing up a month or two post-elimination is most likely a reintroduction. Studies have shown that bed bugs are highly attracted to previous harborage. In fact, repellency studies have shown some products to have repellency in clean harborages, but not on harborages with previous activity.

In many cases, it is a bug brought home in the same manner that caused the original infestation. In multi-family dwellings, it may be bed bugs dispersing from a heavy infestation in an adjacent unit. (This only reinforces the necessity of inspecting adjacent units in conjunction with a treatment.)

Although preventing reintroductions cannot be guaranteed, helping people understand the common methods of reintroductions can go a long way in minimizing the chances. Depending on the circumstances, it can be difficult to explain this before pest management procedures begin. You may need to overcome language or societal barriers to educate tenants about preventing reintroduction.

Achieving the best results comes when these instructions are written as well as explained. The use of interceptors also can be a valuable tool for demonstrating elimination has occurred and for preventing a re-infestation.

You can reach contributor Mark Sheperdigian, BCE, vice president of technical services, Rose Pest Solutions, Troy, Mich., at


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