The Efficacy of a Pyrethroid-impregnated Mattress Liner on Multiple International Strains of Cimex lectularius (Hemiptera: Cimicidae) and Cimex hemipterus (Hemiptera: Cimicidae).

Modern bed bugs are resistant to multiple insecticide classes, particularly the pyrethroids. The efficacy of pyrethroid-impregnated mattress liners marketed for bed bug management has been variable. This study evaluated the efficacy of a permethrin-impregnated mattress liner, ActiveGuard, against 24 bed bug strains, consisting of both Cimex hemipterus (F.) and Cimex lectularius L. A 'mat assay', employing an allethrin-impregnated mat, was used to establish the pyrethroid resistance profile of all strains. Three experiments were conducted to evaluate the effect of ActiveGuard exposure on bed bug knockdown: 1) exposing the bed bugs continuously on the liner for up to 24 d, 2) holding the bed bugs on the liner for either 4 or 6 h, and 3) placing a noninsecticide treated fabric above the liner with the bed bugs held continuously on top. Our results indicated that all modern strains (collected within the last 15 years during the current resurgence) were pyrethroid-resistant, although the magnitude of resistance was highly variable between strains. In the continuous exposure study, an incomplete knockdown was recorded for most modern bed bug strains, with some having no knockdown even up to 7 d of constant exposure. In the 4 or 6 h exposure study, the level of knockdown was reduced even further, and very few bed bugs were knocked down in the double fabric study. The results of this study indicate that pyrethroid-impregnated mattress liners are not likely to be effective in the management of most modern bed bug infestations involving either C. hemipterus or C. lectularius.

Quantification of Fecal Spot Production as a Measure of Environmental Contamination Based on Common Bed Bug (Hemiptera: Cimicidae: Cimex lectularius L.) Population Size.

The presence of fecal spots has often been used to verify the existence of a bed bug (Cimex lectularius) infestation. However, no research has been conducted to determine how much fecal material that a bed bug population produces over time. In this study, the number of fecal spots that each nymphal life stage was capable of producing after a bloodmeal was quantified. Adult fecal spots were also quantified to determine if there was consistent production between feedings. During this study, it was discovered that bed bugs produced visible fecal spots and clear spots that were only visible under ultraviolet light. Therefore, three types of fecal spots were quantified: dark feces, light feces, and clear spots. Clear spots were produced in greater amounts (38.5-55.5%) than either dark spots (27.3-40.7%) or light spots (17.3-21.9%). For example, 5th instar bed bugs were thought to produce an average of 21 spots (dark and light) after a single bloodmeal. However, using the ultraviolet light, it was found that the 5th instars actually produced an average of 44.7 spots. Using the total fecal spot data collected during this study, researchers could project contamination potential for an infestation starting with a single gravid female over 30, 60, and 90 d. In addition, the amount of area covered by these spots was projected to be over 12 m2 in just 3 mo, which could greatly reduce the environmental and aesthetic quality of a home.