A new study finds that placing just a few pitfall traps for bed bugs—or even just one—can have a high success rate in detecting low-level infestations in a studio or one-bedroom apartment, which could lower the cost of monitoring and increase adoption in housing facilities where resources for pest management are limited. (Photo credit: Gary Alpert, Harvard University, Bugwood.org)

While the common bed bug (Cimex lectularius) can target all varieties of human habitats, it is a significant concern in settings such as multi-unit, low-income housing, especially those for the elderly or disabled, where the pest can spread easily and resources for management of the pest are often limited.

However, a new study published in March in the Journal of Economic Entomology offers encouraging evidence that a simple monitoring plan can effectively detect bed bug infestations and potentially reduce management costs. The results show even just one passive pitfall trap placed in a studio or one-bedroom apartment can detect low-level bed bug infestations four out of five times.

Karen Vail, Ph.D., professor and extension urban entomologist at the University of Tennessee and lead author of the study, says the success rate was similar to those found in studies of monitoring plans with greater numbers of traps. “The lower cost of using fewer monitors and less time required to place them may encourage pest management professionals and housing managers to use them more frequently and thus detect bed bugs before they spread,” she says.

Researchers at the University of Tennessee tested various bed bug monitoring devices in arrangements of one, two, or four traps per apartment and found pitfall traps (left and middle, labeled A and B) to be much more effective in detecting low-level bed bug infestations than sticky traps (right, shown open and closed, labeled C and D). (Photo credit: Karen Vail, Ph.D.)

Vail and research specialist Jennifer Chandler conducted their study in three high-rise apartment buildings in Knoxville, Tennessee, in the winter of 2014. They tested two pitfall-style traps and one sticky trap, and they also varied the number of traps placed per apartment (one, two, or four). Over the course of the eight-week test period, the pitfall monitors detected bed bugs in 79 percent to 88 percent of apartments where bed bugs were otherwise confirmed to be present. The sticky monitor, however, had only a 39 percent detection rate. In the apartments with pitfall traps, there was no significant improvement in detection when placing two or four monitors versus placing just one.

Previous studies have shown that placing larger numbers of pitfall monitors (anywhere from eight to 40) in an apartment can detect bed bugs in just one or two weeks, while Vail and Chandler’s study showed the reduced number of pitfall monitors took longer—four weeks, on average—to detect the bed bugs. That rate, however, still fits within pest management plans in housing where inspections may only be conducted at one- to three-month intervals, the researchers note.

Vail says her long-term goal aims to show housing managers that quick visual inspections combined with optimal number and placement of pitfall monitors can be cost effective and increase adoption of proactive monitoring for bed bug infestations. “Housing managers must realize early detection will provide savings due to reduced treatment costs and that they should avoid basing monitoring program selection exclusively on the cost of the monitoring program alone,” she says.