UC Berkeley researchers put one brand of mattress and box spring encasements to the test.
Editor’s note: The research reported here was funded by London Luxury. For additional information about the firm, visit www.londonlux.com.
Bed bugs, Cimex lectularius, have plagued humans for thousands of years. During most of the 20th century, developed countries enjoyed a brief intermission from these blood-sucking pests. This intermission was ushered in by the inventions and widespread, indiscriminate uses of DDT and synthetic organophosphates. The world has changed dramatically since the ban and removal of these products. Inexpensive international travel and reports of pesticide resistance, among other reasons, are often cited for the bed bug resurgence. Whatever the reasons, they are back with a vengeance in an era that values environmental consciousness and responsibility. Integrated Pest Management (IPM) is critical in bed bug management because prevention and treatment are both necessary components in facilitating their control.
One tool, mattress and box spring encasements, can be an integral part of an IPM program. Encasements can eliminate bed bug harborages, or in the case of an existing infestation, trap bed bugs in these difficult-to-treat areas.
Our Study. In an attempt to bridge part of the knowledge gap between manufacturer claims and actual efficacy, this study evaluated London Luxury Bed Bug Mattress Protector Encasements in preventing the escape of adult and late instar bed bugs. Experimental units were made of polyvinyl chloride (PVC) tube frames constructed to the dimensions of a standard twin-sized bed (9 by 39 by 75 inches), and then covered with a mattress encasement (see Fig. 1 below). The structural integrity of each mattress encasement was confirmed before the trial began. The design was balanced, having five replicates for each of two randomly assigned treatments. Treatments differed by having either a fully engaged zipper (treated unit) or a zipper left open about 2 to 3 feet (untreated control unit).
Twenty male and female adults and late instar bed bugs were released inside of the mattress encasements (see Fig. 2B below). A large plastic, transparent storage bag was pulled over the experimental unit and sealed to contain any escaped bed bugs (Fig. 2 below). Experimental units were evaluated weekly for escaped bed bugs for five weeks (see Table below). At the trial conclusion, units were treated with dichlorvos and all encasements were zipped to prevent bed bug movement into or out of the encasement. At final count, units were dismantled and bed bugs were recovered and counted.
One hundred percent of the bed bugs (20 per unit) were contained and recovered from inside the encasement of all five treated units (fully engaged zippers). In contrast, within one week after trial initiation, one untreated control unit had an escaped bed bug. By week 4, all five untreated control units had at least one escaped bed bug (Table 1). Untreated controls, as a group, showed increasing numbers of escaped bed bugs throughout the duration of the trial, reaching a high of 12 escaped bed bugs. Individual untreated control units had a minimum of one and a maximum of four escaped bed bugs. In short, the five treated units (fully zipped) were successful in preventing bed bug escape, while the five untreated control units (unzipped) failed at preventing bed bug escape (p<0.05, Fisher’s Exact Test).
Final Thoughts. The London Luxury Bed Bug Mattress Protector, used according to label instructions, excluded adult and late instar bed bugs from the mattress. Even one escaped adult female bed bug has serious implications to bed bug populations, as she may lay up to 500 eggs over a year. The use of mattress encasements facilitates bed bug infestation management by eliminating harborages, providing a stark surface for easy detection of telltale bed bug signs, and can trap bed bugs during an active infestation.
Sara Moore, Robin Tabuchi and Vernard Lewis are members of the UC Berkeley Urban Pest Management Center, UC Richmond Field Station, Richmond, Calif. Gail Getty is a former member who has retired and now works for the Domus Institute.