Bed Bug Control: Heat and Cold

2019

Ashbrook, A. R., M. Scharf, G. Bennet, and A. Gondhalekar2019. Bed bugs (Cimex lectularius L.) exhibit limited ability to develop heat resistance. PLoS One. 14(2). doi: 10.1371/journal.pone.0211677

“The global population growth of the bed bug, Cimex lectularius (L.), is attributed to their cryptic behavior, diverse insecticide resistance mechanisms, and lack of public awareness. Bed bug control can be challenging and typically requires chemical and non-chemical treatments. One common non-chemical method for bed bug management is thermal remediation. However, in certain instances, bed bugs are known to survive heat treatments. Bed bugs may be present after a heat treatment due to (i) abiotic factors associated with the inability to achieve lethal temperatures in harborage areas for a sufficient time period, (ii) re-infestation from insects that escaped to cooler areas during a heat treatment or (iii) development of physiological resistance that allows them to survive heat exposure. Previous research has investigated the optimal temperature and exposure time required for either achieving complete mortality or sublethally affecting their growth and development. However, no research has examined bed bug populations for their ability to develop resistance to heat exposure and variation in thermo-tolerance between different bed bug strains. The goals of this study were: i) to determine if bed bugs could be selected for heat resistance under a laboratory selection regime, and ii) to determine if bed bug populations with various heat exposure histories, insecticide resistance profiles, and geographic origins have differential temperature tolerances using two heat exposure techniques (step-function and rampfunction). Selection experiments found an initial increase in bed bug survivorship; however, survivorship did not increase past the fourth generation. Sublethal exposure to heat significantly reduced bed bug feeding and, in some cases, inhibited development. The step-function exposure technique revealed non-significant variation in heat tolerance between populations and the ramp-function exposure technique provided similar results. Based on these study outcomes, the ability of bed bugs to develop heat resistance appears to be limited.”


2018

Rukke, B. A., R. Sivasubramaniam, T. Birkemoe, and A. Aak2018. Temperature stress deteriorates bed bug (Cimex lectularius) populations through decreased survival, fecundity and offspring success. PLoS One. 13(3): e0193788. doi: 10.1371/journal.pone.0193788

“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.”


2017

Rukke, B. A., M. Hage, and A. Aak2017. Mortality, fecundity and development among bed bugs (Cimex lectularius) exposed to prolonged, intermediate cold stress: Bed bug cold treatment-mortality, fecundity and development. Pest Management Science. 73: 838–843. doi: 10.1002/ps.4504

“Bed bugs (Cimex lectularius L.) have returned as a nuisance pest worldwide. Their ability to withstand different types of environmental stress should be explored in order potentially to increase the efficiency of control methods. Immediate and long-term effects of exposure to temperatures from 0 to −10 °C for 1, 2 and 3 weeks are reported. Fifth-instar nymphs and adults were exposed to constant or fluctuating temperatures. Increased cold and extended time yielded higher mortality; nymphs were more resilient than adults at the shorter durations of exposure. At intermediate temperatures, mortality was higher at constant compared with fluctuating temperatures, whereas all individuals died after 3 weeks of exposure to −7 °C. The success among survivors after cold treatment was also affected in terms of reduced egg production, hatching success and the ability of fifth-instar nymphs to advance into the adult stage; however, nymphs produced after cold treatment developed normally. Detrimental effects of prolonged exposure to low temperatures were seen in bed bugs both during and after cold treatment. The results suggest that temperatures below −7 °C can be applied by laymen to control this pest in small items if available treatment time is of less concern.”


2016

Loudon, C. 2016. Rapid killing of bed bugs (Cimex lectularius L.) on surfaces using heat: application to luggage. Pest Management Science. 73(1): 64–70. doi: 10.1002/ps.4409

“The resistance of bed bugs (Cimex lectularius L.) to chemical insecticides has motivated the development of non-chemical control methods such as heat treatment. However, because bed bugs tend to hide in cracks or crevices, their behavior incidentally generates a thermally insulated microenvironment for themselves. Bed bugs located on the outer surface of luggage are less insulated and potentially more vulnerable to brief heat treatment. Soft-sided suitcases with adult male bed bugs on the outside were exposed to an air temperature of 70–75 °C [158-167°F]. It took 6 min to kill all of the bed bugs, even those that had concealed themselves under zipper flaps or decorative piping. During heating, only one bed bug (out of 250 in total) moved into the luggage (through a closed zipper). Over long periods of time (24 h) at room temperature, adult male bed bugs on the exterior of luggage only infrequently moved inside; only 3% (5/170) had moved inside during 24 h. Brief exterior heat treatment of luggage is a promising way to reduce the spread of bed bugs being transported on the outer surface of luggage. This treatment will not kill bed bugs inside the luggage, but could be a component of integrated management for this pest.”


2015

Rukke, B. A., A. Aak, and K. S. Edgar2015. Mortality, temporary sterilization, and maternal effects of sublethal heat in bed bugs. PLoS One. 10. doi: 10.1371/journal.pone.0127555

“Adult bed bugs were exposed to the sublethal temperatures 34.0°C, 35.5°C, 37.0°C, 38.5°C, or 40.0°C for 3, 6, or 9 days. The two uppermost temperatures induced 100% mortality within 9 and 2 days, respectively, whereas 34.0°C had no observable effect. The intermediate temperatures interacted with time to induce a limited level of mortality but had distinct effects on fecundity, reflected by decreases in the number of eggs produced and hatching success. Adult fecundity remained low for up to 40 days after heat exposure, and the time until fertility was restored correlated with the temperature-sum experienced during heat exposure. Three or 6 days of parental exposure to 38.5°C significantly lowered their offspring’s feeding and moulting ability, which consequently led to a failure to continue beyond the third instar. Eggs that were deposited at 22.0°C before being exposed to 37.0°C for 3 or 6 days died, whereas eggs that were exposed to lower temperatures were not significantly affected. Eggs that were deposited during heat treatment exhibited high levels of mortality also at 34.0°C and 35.5°C. The observed negative effects of temperatures between 34.0°C and 40.0°C may be utilized in pest management, and sublethal temperature exposure ought to be further investigated as an additional tool to decimate or potentially eradicate bed bug populations. The effect of parental heat exposure on progeny demonstrates the importance of including maternal considerations when studying bed bug environmental stress reactions.”


2013

Olson J. F., M. Eaton, S. A. Kells, V. Morin, and C. Wang2013. Cold tolerance of bed bugs and practical recommendations for control. Journal of Economic Entomology. 106(6): 2433-2441. doi:10.1603/EC13032

“Bed bugs were exposed to freezing temperatures for various exposure times to determine cold tolerance and mortality estimates for multiple life stages. The mean supercooling point for all bed bug life stages ranged from −21.3°C to −30.3°C, with the egg stage reporting the lowest value. A probit analysis provided a lower lethal temperature (LLT99) of −31.2°C when estimates from all life stages were combined, demonstrating that all stages of bed bugs are not capable of surviving temperatures below body freezing and are therefore freeze intolerant. At conditions above the LLT99, bed bug mortality depended on temperature and exposure time at temperatures above LLT99. Based on our model estimates, survival was estimated for temperatures above −12°C even after 1 wk of continuous exposure. However, exposure to temperatures below −13°C will result in 100% mortality in d to ensure mortality of all life stages. Unfortunately, sublethal exposure to lower temperatures did not prevent subsequent feeding behavior in surviving stages. Practical recommendations for management of potentially infested items are discussed.”


Puckett, R. T., D. L. McDonald, and R. E. Gold. 2013. Comparison of multiple steam treatment durations for control of bed bugs (Cimex lectularius L.). Pest Management Science. 69(9): 1061–1065. doi: 10.1002/ps.3467

“The work reported herein was designed to refine our understanding of the duration of bed bug/steam contact necessary to affect mortality of bed bugs in laboratory trials. Beg bug eggs, nymphs and adults were exposed to three steam treatment exposure periods in these trials. Mean percentage mortality of bed bug eggs was 100% (regardless of duration of exposure), and that of nymphs and adults ranged from 88.0 to 94.0%. Survivorship of nymphs and adults in the trials was the result of experimental protocol restrictions that would not usually be associated with actual pest management efforts. The treatment equipment used in these trials is portable and relatively inexpensive and represents a non-chemical means of killing all life stages of bed bugs. While this method would likely be seen as an inefficient means of remediating a mature bed bug infestation within a structure, it does represent a practical component of integrated management of this pest insect.”


2011

Kells, S. A., and M. J. Goblirsch2011. Temperature and time requirements for controlling bedbugs (Cimex lectularius) under commercial heat treatment conditions. Insects. 2(3): 412–422. doi: 10.3390/insects2030412

“The objective of these laboratory experiments was to explore requirements to produce maximum mortality of bed bugs from heat exposure using conditions characteristic of whole-room heat treatments. The lethal temperatures required for 99% mortality (LTemp99) of bed bug stages was determined. Higher temperatures were required to kill eggs (LTemp99 = 54.8 °C [130.64 °F]) than adults (LTemp99 = 48.3 °C [118.94 °F]).  When exposed to 45 °C (113 ºF), adult bed bugs had an LTime99 of 94.8 min, whereas eggs survived for 7 h. Eggs survived only 71.5 min at 48 °C (118.4 °F).”


Lehnert, M. P., R. M. Pereira, P. G. Koehler, W. Walker, and M. S. Lehnert2011. Control of Cimex lectularius using heat combined with dichlorvos resin strips. Medical and Veterinary Entomology. 25(4): 460–464. doi: 10.1111/j.1365-2915.2011.00944.x

“Successful management of the bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), is difficult because of its pesticide resistance, which can allow a reduction in population, but not elimination. We evaluated the effect of heat and/or air circulation on the efficacy of dichlorvos resin strips in the control of bed bugs. Treatments were performed in unoccupied dormitory rooms and consisted of dichlorvos resin strips containing 18.6% active ingredient, the same strips + fan, and strips + fan + heat. The mortality of recently fed bed bugs and weight loss of the dichlorvos strips were evaluated over 7 days. Dichlorvos resin strips killed bed bugs and eggs in just over 7 days. The addition of a fan or a fan + heat decreased time to 100% mortality to 3 days and 36 h, respectively. Eggs located in treated rooms did not hatch. Resin strips in the strips + fan treatment and the strips + fan + heat treatment volatilized 10 and 70 times, respectively, faster than strips in the strips-only treatment. The addition of heat in treatments with dichlorvos resin strips enhances the overall efficacy of the volatile insecticide and reduces the time required to eliminate live bed bugs and eggs.”


2010

Naylor, R. A., and C. J. Boase. 2010. Practical solutions for treating laundry infested with Cimex lectularius (Hemiptera: Cimicidae). Journal of Economic Entomology. 103(1): 136–139. doi: 10.1603/EC09288

Researchers evaluated various laundering methods to disinfect clothing with bed bugs. All life stages (adults, nymphs, and eggs) were killed by (1) washing at 60°C [140°F], (2) tumble drying for at least 30 minutes on the hot cycle (>40°C [104°F]), (3) dry cleaning with perchloroethylene, or (4) freezing for at >2 hours at -17°C [1.4°F] (2.5 kg of loosely packed, dry laundry took ≈8 hours to reach -17°C [1.4°F]). Soaking items in detergent-free water for 24 hours was sufficient to kill bed bug adults and nymphs but there was no effect on eggs.


2006

Doggett, S. L., M. J. Geary, and R. C. Russell. 2006. Encasing mattresses in black plastic will not provide thermal control of bed bugs, Cimex spp. (Hemiptera: Cimicidae). Journal of Economic Entomology. 99(6): 2132–2135. doi: 10.1603/0022-0493-99.6.2132

“The suggestion that bed bug (Cimex spp.; Hemiptera: Cimicidae)-infested mattresses wrapped in black plastic and exposed to sunlight will be heated sufficiently to kill the bed bugs was tested. Two types of mattresses were tested: a thin mattress of solid foam rubber and a thick multilayered inner spring mattress. Temperature probes were placed on both upper and lower sides of the mattresses, which were wrapped in black plastic and placed outside on a summer day for >9 h wherein the ambient temperature peaked at 36.5°C. The maximum recorded temperature on the upper (sun-exposed) sides was 85°C for both mattresses, whereas lower side temperatures for the thick mattress never exceeded 35°C, and some areas of the thin mattress failed to exceed 36.5°C. Therefore, with published thermal death points of 40–45°C depending on exposure time, and opportunities for bed bugs to avoid lethal temperatures by retreating from hot zones, this technique seems to be not suitable for bed bug management.”