Effectiveness of a Sugar-Yeast Monitor and a Chemical Lure for Detecting Bed Bugs

Volatile Organic Compounds: A Promising Tool for Bed Bug Detection

The recent decades' resurgence of bed bugs as a public health concern in industrialized countries has driven an increased interest on new sustainable insecticide-free methods to monitor and control these ectoparasites. Current methods of detection rely mainly on visual inspection or canine scent detection, which are methods that are time-consuming, require experience, are non-specific or require costly mission repetitions. Volatile organic compounds (VOCs) are considered an environmentally friendly alternative and a promising approach for bed bug detection. An overview of the released literature on VOCs, their chemical characteristics and their role in bed bugs' intra- and inter-species communications allowed us to highlight the identification of 49 VOCs in Cimex lectularius (23 molecules) and C. hemipterus (26), which are emitted by both sexes during diverse compartments including aggregation (46), mating (11), defense (4), etc., and all life stages including exuviae or dead bed bugs as a principal indicator of infestation. The latter has a great importance for application of these semiochemicals in successful detection and control management of bed bugs and to prevent their further dispersion. This approach has the advantage of more reliability compared to conventional detection methods with no need for repeated inspections, household furniture moving or resident rehousing for bed bugs' VOC detection, which are commonly performed by active or passive sampling with absorbing tubes and analyzed by gas chromatography-based analytical platforms.

Comparative Efficacy of Superheated Dry Steam Application and Insecticide Spray Against Common Bed Bugs Under Simulated Field Conditions

The common bed bug, Cimex lectularius L., is a difficult urban pest to control. A simulated field study was conducted to compare the efficacy of steam application and an insecticide mixture spray (0.05% acetamiprid and 0.06% bifenthrin mixture) against C. lectularius. Three types of furniture (desk chair, upholstered armchair, and wooden table) were treated in the laboratory. The efficacy of the treatments was evaluated by visual inspection and placement of interceptor traps under the legs of the furniture. One hundred mixed stages of an insecticide-resistant population of C. lectularius were released onto each furniture item. After a 10-day acclimation period, each furniture item received steam treatment, insecticide spray, or no treatment. The second application of treatment was conducted 14 d later. Bed bug counts from interceptors and visual inspections were recorded at 13 d and 28 d after the initial treatment. At 28 d, the mean (± SE) live bed bug count in the steam, spray, and control group was 1 ± 0, 2 ± 1, and 83 ± 10, respectively. Both treatment methods were highly effective in controlling bed bugs on furniture. The mean bed bug count from interceptors in the steam, spray, and control groups were 0.3 ± 0.2, 11 ± 7, and 47 ± 9, respectively. There was no significant difference in the efficacy between steam and spray treatments based on either visual inspection or bed bug counts from interceptors. However, based on interceptor counts, the steam treatment caused faster bed bug population reduction than insecticide sprays.

Detection and monitoring of bed bugs (Hemiptera: Cimicidae): review of the underlying science, existing products and future prospects

Bed bugs, Cimex lectularius L. and C. hemipterus (F.) (Hemiptera: Cimicidae) are hematophagous ectoparasites of humans. Since the resurgence of bed bugs in the late 1990s there has been a corresponding emphasis on development and implementation of integrated pest management (IPM) programs to manage infestations. One critical requirement of IPM is the ability to detect and monitor the target pest. We outline and describe the majority of all known existing devices and technologies developed for bed bug detection and monitoring as well as much of the underlying science. Almost 40 detection and monitoring products have flooded the marketplace, but for various reasons, including price, size, complexity and lack of independent scientific evaluation, they have not been widely adopted for IPM in structures. One product, the ClimbUp® Insect Interceptor, has nine competitors that utilize a similar design. This review also discloses many other technologies and products that are either too expensive or too impractical for use as either consumer or industrial products. We conclude that there is a critical need for inexpensive and effective detection and monitoring traps and lures suitable for widespread adoption by the urban pest control industry. © 2021 Society of Chemical Industry.

Behavioral Response of the Tropical Bed Bug, Cimex hemipterus (Hemiptera: Cimicidae) to Carbon Dioxide

Bed bugs (Cimex spp.) (Hemiptera: Cimicidae) are obligatory blood-sucking insects. Research on their behavioral response to host-derived olfactory cues will be helpful for designing more effective management tools. However, previous studies mainly focused on Cimex lectularius L., while the related studies on Cimex hemipterus (F.) have been rarely reported. In this study, we evaluated the behavioral responses of C. hemipterus to one of the crucial host-derived cues - carbon dioxide (CO2), at various concentrations. Pitfall traps baited with CO2 captured significantly more C. hemipterus (72%) than unbaited ones (28%). In the Y-tube test, bed bugs' exploratory activity (response rate) gradually decreased (from 70 to 27%) as the CO2 concentration increased (from 0.9 to 14.5%); and bed bugs exhibited a significant attraction to CO2 when the tested CO2 concentrations were between 0.9 and 7.3%. Cimex hemipterus were no longer attracted to CO2 after their antennae or mouthparts or both antennae and mouthparts were removed. In conclusion, C. hemipterus are attracted to CO2, and both antennae and mouthparts are important for CO2 perception.

A Case Study of Cimex lectularius L. (Hemiptera: Cimicidae) Infestations in an Office Environment

Most field studies on Cimex lectularius are conducted in residential or hospitality industrial settings. Cimex lectularius infestations in office settings are reported, but are rarely studied. An office environment (~875 m2) consisting of 105 cubicles or pod-seating areas with persistent C. lectularius sightings over a 2-yr period was evaluated for 90 d through intensive trapping to determine C. lectularius distribution and to eliminate the infestation. The study area was partially occupied during the study period. Two treatments of amorphous silica dust (112.5 g dust in total) were applied 29 and 57 d after the first day of monitoring. A total of 32 C. lectularius were captured by interceptors over a period of 55 d. Dry ice traps captured eight additional C. lectularius. Visual inspections identified one chair with live C. lectularius and eggs. The infestation was eliminated on 69 d after initial installation of interceptors. Spatial analysis using Ripley's K and L functions showed a high level of aggregation up to a 15 meter scale. Dispersal of C. lectularius in office settings was limited. Intensive trapping plus limited insecticide dust treatments effectively detected and eliminated C. lectularius.

Temperature stress deteriorates bed bug (Cimex lectularius) populations through decreased survival, fecundity and offspring success

Sublethal heat stress may weaken bed bug infestations to potentially ease control. In the present study, experimental populations exposed to 34, 36 or 38°C for 2 or 3 weeks suffered significant mortality during exposure. Among survivors, egg production, egg hatching, moulting success and offspring proliferation decreased significantly in the subsequent 7 week recovery period at 22°C. The overall population success was negatively impacted by increasing temperature and duration of the stress. Such heat stress is inadequate as a single tool for eradication, but may be included as a low cost part of an integrated pest management protocol. Depending on the time available and infestation conditions, the success of some treatments can improve if sublethal heat is implemented prior to the onset of more conventional pest control measures.

Insect pathogenic fungi and bed bugs: behaviour, horizontal transfer and the potential contribution to IPM solutions

The increasing problem of bed bugs requires the development of new control strategies, and insect pathogenic fungi can contribute towards management. We used laboratory bioassays with Isaria fumosoroseus, Lecanicillium muscarium and Beauveria bassiana to evaluate their virulence to the bed bug. Only B. bassiana significantly affected bed bug survival and was dependent on dose and formulation. A 2% B. bassiana oil formulation induced horizontal transfer to elevate mortality in a 10-day arena bioassay. Temporal distribution of contagious individuals and increasing the dose from 2 to 4% did not increase mortality. Horizontal transfer mainly occurred between adults, and only partly between adults and nymphs. Bed bugs showed activity peaks during the night, and activity was increased by elevated levels of CO₂. Distribution between harbourages was not affected by CO₂ activation, level of infection or the bio-pesticide, and horizontal transfer was not dependent on the degree of aggregation. Movement in the arenas negatively affected horizontal transfer when the number of susceptible individuals was large. Level of infection also influenced behaviour as the bed bug movement increased with elevated disease burden. The use of fungi as a part of an integrated pest management strategy seems to be an interesting option that should be investigated further. B. bassiana kills bed bugs and can be carried to harbourages to target hidden individuals.

Bed bug aggregation on dirty laundry: a mechanism for passive dispersal

Bed bugs have shown a recent and rapid global expansion that has been suggested to be caused by cheap air travel. How a small, flightless and anachoretic insect that hides within its host’s sleeping area manages to travel long distances is not yet clear. Bed bugs are attracted to the odour of sleeping humans and we suggest that soiled clothing may present a similarly attractive cue, allowing bed bugs to ‘hitch-hike’ around the world after aggregating in the laundry bags of travellers. We show that (1) soiled clothing is significantly more attractive than clean clothing to active bed bugs moving within a bedroom sized arena and (2) elevation of CO₂ to a level that simulates human occupancy in the same arena appears to initiate search behaviour rather than direct it. Our results show, for the first time, how leaving worn clothing exposed in sleeping areas when travelling can be exploited by bed bugs to facilitate passive dispersal.

Effect of Feeding History and Time Elapsed From Field Collection on the Movement Behavior and Response to Stimulation in Cimex lectularius (Hemiptera: Cimicidae)

The common bed bug (Cimex lectularius L.) (Hemiptera: Cimicidae) is an obligate blood-sucking insect that has been resurging in many countries. Researching this pest's behavior will help design more effective control methods. In this study, we evaluated the effect of feeding history and time elapsed from field collection on bed bug movement behavior and response to chemical lure or carbon dioxide stimulation in the laboratory. After CO2 was released, bed bugs unfed for 3 d began to return to harborages; in contrast, the ones unfed for 2 and 4 wk spent significantly more time outside their harborages during the first 1 h after than the 1 h before CO2 release. After CO2 release, there was an increase in activity (time spent moving outside harborage) in all bed bugs with different feeding history or time elapsed from field collection. During the 8-h observation period when CO2 was present, bed bug males unfed for 4 wk spent significantly more time exploring outside harborages than the ones unfed for 3 d, 1 wk, and 2 wk. Nymphs collected 1-2 wk and 1 yr ago spent significantly more time exploring outside harborages than the ones collected 43 yr ago. Bed bug's exploratory activity (the total percentage of bed bugs trapped in both baited and unbaited interceptors) was significantly affected by their time elapsed from field collection and their exploratory activity level was 1-2 wk > 6 mo > 5 and 43 yr. Both feeding history and time elapsed from field collection significantly affected bed bug movement, whereas bed bug's response to chemical lure or CO2 (the percentage of bed bugs trapped in the baited interceptor, summarized as the number of bed bugs trapped in the baited interceptor divided by the total number of trapped bed bugs in both baited and unbaited interceptors) was unaffected by the time elapsed from field collection.

Bed Bug (Hemiptera: Cimicidae) Detection in Low-Income, High-Rise Apartments Using Four or Fewer Passive Monitors

Bed bug, Cimex lectularius L., management in low-income, high-rise housing for the elderly and disabled can be difficult. Early detection is key to slowing their spread, and reducing management cost and time needed for control. To determine the minimum number of passive monitors needed to detect low-level bed bug infestations in this environment, we evaluated three monitors placed one, two, or four per apartment in a 3 by 3 experimental design. One sticky monitor, The Bedbug Detection System, and the two pitfall monitors, ClimbUp Insect Interceptors BG and BlackOut BedBug Detectors, were evaluated. Bed bugs were trapped by the ClimbUp Insect Interceptors BG and the BlackOut BedBug Detector in 88% and 79% of apartments, respectively, but only in 39% of the apartments monitored with The Bedbug Detection System. The Bedbug Detection System required significantly longer time to detect bed bugs than either the ClimbUp Insect Interceptor BG or the BlackOut BedBug Detector. With the less effective Bedbug Detection System data removed from analyses, detection rates ranged from 80 to 90%, with no significant differences among one, two, or four monitors per apartment. Results indicate it is especially important to include a bed placement when only placing a few monitors. Future work should compare the combination of cursory visual inspections with various monitor numbers and placements per apartment to determine the most efficient, cost-effective system that will be accepted and implemented in low-income housing.

Relatively Small Quantities of CO2, Ammonium Bicarbonate, and a Blend of (E)-2-Hexenal Plus (E)-2-Octenal Attract Bed Bugs (Hemiptera: Cimicidae)

Bed bugs, Cimex lectularius L., feed on humans, have increased exponentially in the past two decades in many major cities throughout the world, have caused intense infestations, and have become a significant health concern. Improved traps are needed to detect early infestations, to assess control programs, and for control of bed bugs. Carbon dioxide released alone or simultaneously with other attractants into three types of traps at the relatively low rate of 1 ml/min caught significantly more bed bugs than untreated controls in a 183- by 183-cm arena. This finding may enable CO2 to be used more economically in traps. Three percent ammonium bicarbonate released at a rate of ≤0.03 ml/h also caught significantly more bed bugs than untreated controls. A blend of (E)-2-hexenal and (E)-2-octenal at concentrations of 0.025% or 0.1% each and released at 0.02 ml/h attracted significantly more bed bugs than untreated controls. These findings ought to improve detection of bed bugs.

Desiccant dust and the use of CO2 gas as a mobility stimulant for bed bugs: a potential control solution?

The common bed bug (Cimex lectularius, Hemiptera; Cimicidae) infests homes and service industries, and the number of infestations has greatly increased over the past 20 years. At present, no cost-effective control methods are available, and eradication programs are expensive and laborious. We investigated the control potential of desiccant dust in combination with CO₂ as a bed bug activity stimulant. An initial experiment with two desiccant dusts was followed by arena studies with varying doses, available hiding places and the presence or absence of host signals. Finally, we conducted a field experiment with Syloid 244FP with or without CO₂ gas. Syloid was superior compared to diatomaceous earth, and effective at the concentration of 1.0 g/m² in the field experiment. The number of harborages and partial application of desiccant dust decreased mortality in the laboratory. Bed bug activation by CO₂ appeared of minor importance in the arena studies, but was crucial for the eradication in the student dormitories. In fact, all 5 bed bug-infested dormitories with a combined treatment of desiccant dust and CO₂ were freed of bed bugs, whereas eradication was not successful in any of the 6 dormitories with only desiccant dust treatment. The different results in the laboratory and field experiment were most likely caused by the longer activation and higher dose of CO₂ used in the field experiment than the laboratory experiment. Our study showed that application of desiccant dust in combination with release of CO₂ gas to mimic human presence is a promising option for bed bug control.

Using research and education to implement practical bed bug control programs in multifamily housing

Multifamily housing facilities serving low-income populations have been at the forefront of bed bug outbreaks. Research conducted in the past 8 years has consistently proven that integrated pest management (IPM) is the best approach for successful suppression of bed bug infestations. Bed bug IPM in multifamily settings is especially dependent upon a collaborative community or building-wide effort involving residents, building staff and pest control technicians. Other components of a bed bug IPM program include regular monitoring to detect early-stage bed bug infestations and combined use of non-chemical and chemical interventions. Lastly, to reduce reinfestation rates and costs associated with bed bug control, it is critical to continue periodic monitoring and implement preventive control measures even after successful elimination of bed bugs has been achieved.