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Research Article
Received: 25 December 2017 Revised: 19 March 2018 Accepted article published: 15 April 2018 Published online in Wiley Online Library:
(wileyonlinelibrary.com) DOI 10.1002/ps.4933
Efficacy of three different steamers for control
of bed bugs (Cimex lectularius L.)
Desen Wang,a,b Changlu Wang,b* Guohong Wang,cChen Zha,bAmanda L
Eidenband Richard Cooperb
Abstract
BACKGROUND: Bed bugs, Cimex lectularius L., have become one of the most difficult urban pests to control. Steam treatment is
reported to be an effective method to kill bed bugs and is considered to be an important component of bed bug integrated pest
management (IPM). We evaluated and compared the efficacies of two affordable consumer-grade commercial steamers and a
commonly used professional-grade steamer for killing bed bugs.
RESULTS: In laboratory experiments, the consumer-grade steamers at affordable prices achieved the same high control efficacy
as the professional-grade steamer for treating bed bugs exposed on mattresses (100% bed bug mortality for all steamers),
located beneath a fabric cover (>89% bed bug mortality for all steamers), or hiding in cracks (100% bed bug mortality for all
steamers). Bed bugs located behind a leather cover did not suffer significant mortality from steam treatment regardless of the
type of steamers used and the treatment duration.
CONCLUSION: Proper use of steamers can kill all life stages of bed bugs. Affordable consumer-grade steamers are as effective
as professional-grade steam machines for eliminating bed bugs resting on mattresses and hiding behind fabric materials or in
cracks.
© 2018 Society of Chemical Industry
Keywords: bed bug; steam treatment; efficacy; integrated pest management
1 INTRODUCTION
The common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae),
is an obligate blood-sucking insect that feeds upon humans and
other animals.1The recent resurgence of this pest worldwide,
except in Antarctica, has drawn the attention of many researchers.2
A large number of methods for killing or monitoring bed bugs
have been described and developed over the past 10 years.2,3
Because of their widespread resistance to insecticides and cryptic
and secretive behavior, bed bugs are considered to be one of the
most difficult urban pests to control.2,4– 6 Non-chemical treatments
are considered an important component in bed bug management
practices and can provide an effective alternative to insecticides.3,7
As one of the non-chemical control methods, heat treatment
is currently used for control of stored food product pests8,9 as
well as wood-destroying pests.10– 12 Bed bugs are sensitive to
high temperatures; thus, heat treatment has been applied as a
practical and effective means of bed bug control.2Pereira et al.13
reported that mortality of bed bug adults started at 41 ∘Cwith
an exposure time of 100 min, and this time gradually decreased
as the temperature increased, to about 1 min at 49 ∘C. Johnson14
demonstrated that all stages of bed bugs are killed after exposure
to 45 ∘C for 1 h. The target heat treatment temperature used for
killing bed bugs by the professional pest management industry is
between 45 and 52 ∘C.15– 17
Heat can be applied via hot laundering/drying of infested cloth-
ing and bedding,18 and through the use of portable heat chambers
or structural heat treatments.2,19,20 Loudon20 demonstrated that all
bed bugs on the outer surface of luggage would be killed even
if they were only exposed to an air temperature of 70– 75 ∘Cfor
6 min. The use of steam is another effective method, which capi-
talizes on the delivery of lethal temperatures for treatment of bed
bugs.19,21– 24 Puckett et al.22 reported that steam treatment could
effectively kill bed bug eggs, nymphs, and adult males, when the
steam attachment was placed directly on top of them, moving the
steamer at a speed of 10 s per 30.50cm. However, it is still unclear
whether steam treatment is effective at killing bed bugs when they
are hiding beneath fabric surfaces or in cracks and crevices.
Expensive professional-grade steamers have already been
proven to be effective in killing bed bugs, and they are often
used by pest management professionals in bed bug treatment.19
The Amerivap Systems STM-BASIC Steamax Commercial Steam
Cleaner (Amerivap Systems, Inc., Dawsonville, GA, USA), com-
monly used by pest management professionals, retails at $1259
(https://www.amazon.com), and is therefore not affordable to
most consumers. During our visits to bed bug-infested apart-
ments in previous studies, we found that residents had purchased
more affordable steamers, in an effort to get rid of bed bugs
∗Correspondence to: C Wang, Department of Entomology, Rutgers University,
New Brunswick, NJ 08901, USA. E-mail: changluw@rutgers.edu
aKey Laboratory of Bio-Pesticide Innovation and Application of Guangdong
Province, Department of Entomology, College of Agriculture,South China Agri-
cultural University, Guangzhou, China
bDepartment of Entomology, Rutgers University, New Brunswick, NJ, USA
cCollege of Life Science, Fujian Normal University,Fuzhou, China
Pest Manag Sci (2018) www.soci.org © 2018 Society of Chemical Industry
www.soci.org D Wang et al.
in their homes by themselves. Steamers that cost <$100 are
widely available to consumers, and they can be used as an
effective ‘do-it-yourself’ tool by consumers for bed bug control.
However, no data are available on the efficacy of inexpensive
consumer-grade steamers for bed bug control.
The objective of this study was to evaluate the bed bug control
efficacies of three steamers under various scenarios. Our results
provide practical recommendations for the proper use of steamers
in bed bug management.
2 EXPERIMENTAL METHODS
2.1 Bed bugs
Bed bugs were collected in 2009 from multiple infested apart-
ments in Bayonne, New Jersey, USA. They were maintained in
plastic containers (5 cm diameter and 4.7 cm height; Consolidated
Plastics, Stow, OH, USA) with folded papers as harborages [40mm
length (L) and 30 mm width ( W); Universal Stationers Supply Co.,
Deerfield, IL, USA] and kept in an incubator (Percival Scientific, Inc.,
Perry, IA, USA) at a temperature of 26 ±1∘C, relative humidity of
40 ±10%, and a photoperiod of 12:12 h (light:dark). Bed bugs were
fed weekly on defibrinated rabbit blood (Hemostat Laboratories,
Dixon, CA, USA) using a Hemotek membrane-feeding system (Dis-
covery Workshops, Accrington, UK).
Toobtain bed bug eggs, one piece of blue fabric (L ×W: 8 ×8cm;
65% polyester and 35% cotton; Palencia Broadcloth; Springs Cre-
ative Products Group, LLC, Rock Hill, SC, USA) was exposed to
30–40 fed and mated females for 4 days before the experiment,
so that the age of eggs deposited on the fabric was 0–4 days after
being laid. Bed bugs were only allowed access to one side of the
fabric for the deposition of eggs. To achieve this, the fabric was
placed in a Petri dish (9 cm diameter and 2.5 cm height; Fisher Sci-
entific, Pittston, PA, USA), and a plastic ring (6.5 cm diameter and
2 cm height) was placed on the fabric to confine bed bugs. The
inner wall of the plastic ring was coated with a thin film of fluo-
ropolymer resin (BioQuip Products, Rancho Dominguez, CA, USA)
to prevent bed bugs from escaping.
Adult males (unknown age) and nymphs (4th– 5th instar) used in
all experiments were unfed for 6– 7 days. Female adults were not
used to prevent oviposition in the experimental arenas. All exper-
iments were conducted in a laboratory with a mean temperature
of 24.5 ∘C during the study period.
2.2 Steamers
Three different steam machines were compared. Two were
consumer-grade steamers, the HAAN HS-20R Handheld Steam
Cleaner (HAAN Corporation, Lancaster, PA, USA), henceforth
referred to as ‘HAAN’, and the Steamfast SF-370WH Multi-Purpose
Steam Cleaner (Steamfast, Andover, KS, USA), henceforth ‘Steam-
fast’. The third was the aforementioned professional-grade
machine, the Amerivap Systems STM-BASIC Steamax Commercial
Steam Cleaner, henceforth referred to as ‘Steamax’ (Table 1).
These three steam machines varied significantly in price. They
were selected because we found that homeowners used cheap
steamers for self-control of bed bugs and pest management
professionals typically use expensive/specialized steamers. The
attachment of each steamer used in our study is shown in Fig. 1.
Steamax has three working pressures: low (310 kPa), medium
(379 kPa), and high (448 kPa). In experiment 1, the medium work-
ing pressure (379 kPa) was selected to treat bed bugs on the
surface of the mattress; in experiments 2 and 3, the high working
Figure 1. Steamer attachment used in the experiments.
pressure (448 kpa) was used to treat bed bugs that were hiding
under a fabric cover or in a crack. The HAAN and Steamfast steam-
ers both had a single working pressure (the pressure was not
specified in the manufacturers’ product instructions).
2.3 Experiment 1: treating bed bugs on the mattress surface
A mini mattress [L ×W×height (H): 30 ×30 ×22 cm] was placed
in a plastic tray (L ×W×height: 80 ×75 ×5 cm) (Fig. 2a). For each
treatment, a total of 25 nymphs and 25 adult males were released
onto the mini mattress (three to four males and three to four
nymphs at each of the eight corners) 1 h before treatment; 50 –100
eggs along with the fabric were attached to the mattress surface
immediately before treatment to avoid the possibility of the bed
bugs moving under the fabric prior to treatment.
Two tests were included in this experiment. In the first test, only
the mattress surfaces (including the top, sides, and underside sur-
faces) were steamed; in the second test, both the mattress sur-
faces and the floor of the plastic tray under and around the mat-
tress were steamed. In each test, four treatments (HAAN, Steam-
fast, Steamax, and untreated control) were included. Each treat-
ment was replicated six times; therefore, a total of 24 treatments
were conducted for each test. For each steamer, the moving speed
of the steamer attachment during the first and second tests was
same (3 cm per second), but more time was spent steaming in the
second test, because the tray under and around the mattress was
also steamed.
During treatment, the steamer attachment was kept approxi-
mately 1 cm away from the mattress surface. To minimize the pos-
sibility of escape during the steam treatment, the sequence of
steam treatments was from bottom to top of the mattress. Bed
bugs stayed both along the stitches on the mattress surface and at
the edges, so the whole mattress surface was steamed to ensure
that all bed bugs (eggs, nymphs, and adults) were exposed to
steam. The mini mattress in the control received the same num-
ber of bed bugs with no steam treatment. For each treatment,
the maximum temperature on the surface of the mattress was
recorded during treatment using a thermocouple thermometer
(Cole-Parmer Instrument Company, Vernon Hills, IL, USA), and the
treatment duration was recorded using a digital timer (National
Presto Industries, Inc., Eau Claire, WI, USA).
After treatment, the pieces of fabric with bed bug eggs were
placed in Petri dishes (6 cm diameter and 1.5 cm height; Fisher
Scientific, Pittsburgh, PA, USA) and transferred to an incubator
at 26 ±1∘C. Each Petri dish lid had a 1.5-cm-diameter screened
area for ventilation. Egg mortality was recorded after 14 days.
Unhatched eggs were considered dead. The nymphs and adult
males in each arena were transferred separately into Petri dishes
(6 cm diameter and 1.5 cm height) and were kept in an incubator
at 26 ±1∘C. The bottom of each dish had a piece of filter paper
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Table 1. Prices and specifications of the three steamers. Except for the prices, the information was obtained from the manufacturers’ product
instructions. Price information was obtained from http://www.amazon.com
Steamer Price Wattage (W ) Water capacity (mL) Heat-up time (min) Operating time (min)
HAAN $75.11 1000 200 <315
Steamfast $101.94 1500 1420 8 45
Steamax $1259.00 1700 2400 14 90
Figure 2. Experimental set-up for evaluating the efficacy of steamers for killing bed bugs resting in various habitats. (a) Bed bugs on a mini mattress. (b)
Bed bugs under a cover: (b1) fabric cover with a ClimbUp interceptor underneath; (b2) bed bugs in a ClimbUp interceptor with the fabric cover removed.
(c)Bedbugsinacrack.
on it (3.5 cm diameter; Fisher Scientific). Nymph/adult mortality
was recorded after 1 day. Bed bugs that did not move when
probed with featherweight forceps (BioQuip Products, Rancho
Dominguez, CA, USA) were recorded as dead.
2.4 Experiment 2: treating bed bugs hiding under fabric or
leather covers
White ClimbUp®insect interceptors (15.24 cm diameter and
2.3 cm height; Susan McKnight, Inc., Memphis, TN, USA) were used
as experimental arenas for this study (Fig. 2b). The experimental
set -up consisted of an interceptor placed in a white plastic tray
(L ×W×H: 56 ×44 ×8 cm). The inner wall of the interceptor was
coated with a thin film of fluoropolymer resin to prevent bed
bugs from escaping. Filter paper was glued onto the bottom
of the interceptor to provide a climbable substrate for the bed
bugs. For each treatment, a total of 20– 30 eggs on a piece of
fabric, or 15 nymphs and 15 adult males were introduced into
each interceptor. The interceptor was covered with a piece of
bed sheet (L ×W: 27 ×27 cm; 100% polyester microfiber), sofa
fabric (L ×W: 27 ×27 cm; cotton-terylene), or sofa leather (L ×W:
27 ×27 cm; artificial leather) 1 min prior to treatment (Fig. 3). The
distance between the bed bugs and the cover was 2.3 cm (the
height of the interceptor). The bed sheet (a normal bed sheet
made from polyester microfiber) was bought from an internet
vendor (https://www.amazon.com); both sofa fabric and sofa
leather were cut from discarded old sofas. During treatment, the
steamer attachment was held on the surface of the cover and
only the area directly under the cover was steamed. Treatment
durations of 15 and 30 s were tested in this experiment. For each
type of cover (bed sheet, sofa fabric, or sofa leather), nine steam
treatments were tested: HAAN0s (control), HAAN15s, HAAN30s,
Steamfast0s (control), Steamfast15s, Steamfast30s, Steamax0s (con-
trol), Steamax15s, and Steamax30s . Interceptors in the control
contained bed bug eggs, or nymphs and adult males, and were
covered with the three types of cover, but did not receive steam
treatment. During each treatment, the maximum temperature
under the cover was recorded by the thermocouple thermometer.
This experiment was replicated six times; therefore, a total of 162
treatments were conducted.
After treatment, mortality of bed bug eggs, nymphs and
adults was monitored following the same method as that in
experiment 1.
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Figure 3. Covers used in experiment 2.
2.5 Experiment 3: treating bed bugs hiding in a crack
Two pieces of wood board (L ×W×H: 9.7 ×9.7 ×1cm)wereused
to construct a wedge-shaped crack (L ×W×H: 9.7 ×1.3 ×9.7 cm)
(Fig. 2c). One side of the crack was sealed with athletic tape (L ×W:
9.7 ×3.7 cm; Walgreen Co., Deerfield, IL, USA), and the other three
sides were open. Before steaming, the crack was placed with the
sealed side lying on a white plastic tray (L ×W×H: 56 ×44 ×8cm)
and was fixed with two wrenches as shown in Fig. 2c. For each
treatment, 20 bed bug eggs on a piece of fabric were placed at a
depth of 8.5 cm from the upper opening of the crack, or 10 nymphs
and 10 adults on a paper harborage were placed at a depth of
6 cm from the upper opening immediately before treatment. In
our experiments, bed bugs did not move out of the crack after
they were placed in it. Five treatment durations (1, 2, 4, 6 and 8 s)
were tested for each steamer. A control was also included when
testing each steamer. The control cracks received bed bugs, but
did not receive steam treatment. The maximum temperature in
each crack (near the eggs or nymphs/adults) was recorded during
steaming. This experiment was replicated three times; thus, a total
of 54 treatments were conducted.
After treatment, mortality of bed bug eggs, nymphs, and adults
was recorded using the same method as in experiment 1.
2.6 Statistical analysis
In all experiments, the mortality of bed bugs (eggs, nymphs or
adults) was <5% in the control (no steam treatment). Corrected
mortality based on Abbott’s formula is used in this paper.25
One-way analysis of variance (ANOVA) was used to compare
the difference among different steamers in experiment 1. When
statistical differences existed among data sets (P<0.05), Tukey’s
honest significant difference (HSD) test was used to separate the
means.
Three-way ANOVA was used for analyzing the temperature and
bed bug mortality data in experiment 2. The three factors were
steamer (HAAN, Steamfast, and Steamax), cover type (bed sheet,
sofa fabric, and sofa leather), and treatment duration (15 and 30 s),
and only their main effects were analyzed. In case of statistical dif-
ferences existing for a factor (P<0.05), the means were separated
using Tukey’s HSD test.
Two-way ANOVA was used to determine the significant of the
difference in temperature in the crack during treatment, and bed
bug mortality data in experiment 3. The two factors were steamer
and treatment duration (1, 2, 4, 6 and 8 s), and only their main
effects were analyzed. In the case of statistical differences existing
among data sets for a factor (P<0.05), the means of this factor
were compared using Tukey’s HSD test.
The percentage data were arcsine square root transformed prior
to analysis, if necessary; other data were normally distributed. All
data analyses were carried out using SPSS version 22.0 (Interna-
tional Business Machines Corp., Armonk, NY, USA).26
3RESULTS
3.1 Treating bed bugs on the mattress surface
There was no significant difference among the three steamers for
percentage of egg mortality, or percentage of nymph and adult
mortality, regardless of the experimental conditions (only mattress
steamed, or both mattress and plastic tray floor steamed). Similarly,
the temperature on the mattress’s surface during treatment and
the treatment duration were similar for all three steamers tested
(Table 2).
During steam treatment in the first test (mattress steamed), the
mean temperatures on the mattress surface were 71.9– 75.4 ∘Cfor
each steamer (Table 2). After treatment, none of the treated eggs
hatched; and 91–93% of nymphs and adults were dead. In the
second test (mattress and plastic tray floor steamed), the mean
temperatures on the mattress surface were 81.5– 82.7 ∘Cforeach
steamer (Table 2). After steam treatment, none of the treated eggs
hatched; and all nymphs and adults were dead.
3.2 Treating bed bugs hiding under a fabric or leather cover
In the bed bug egg treatments, the temperature beneath the
cover varied significantly depending upon the type of cover,
which steamer was used, and the treatment duration (Table 3).
When treating different cover types, the temperature under sofa
leather (36.7–44.6 ∘C) was significantly lower than that under the
bed sheet (64.0 –80.1 ∘C) or sofa fabric (61.3–79.1 ∘C) (Tukey’s
HSD test, P<0.05). The HAAN steamer (37.7 –80.1 ∘C) produced a
significantly higher temperature under the cover compared with
the Steamfast steamer (36.7 –79.0 ∘C) (Tukey’s HSD test, P<0.05).
The 30-s steam treatment (36.7 –80.1 ∘C) induced a significantly
higher temperature under the cover than the 15-s steam treatment
(36.8–79.2 ∘C) (Tukey’s HSD test, P<0.05).
In the bed bug nymph and adult treatments, the temper-
ature under the cover was significantly influenced by cover
type and steamer, but not the treatment duration (Table 3).
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Table 2. Mean (±standard error) treatment duration, temperature during steam treatment, and bed bug control efficacy for the different steamers
used to treat bed bugs on mattresses
Treatment duration (s)
Tem per atu re on t h e
mattress surface during treatment (∘C) % egg mortality % nymph mortality % adult mortality
First test†
HAAN 240.5 ±26.5 71.9 ±3.6 100 93 ±295±1
Steamfast 231.3 ±23.4 72.6 ±2.8 100 91 ±393±2
Steamax 197.8 ±20.9 75.4 ±2.6 100 93 ±391±5
Statistics F2,15 =0.9 F2,15 =0.4 – F2,15 =0.1 F2,15 =0.5
P=0.429 P=0.696 P=0.879 P=0.600
Second test‡
HAAN 517.8 ±29.3 82.7 ±1.3 100 100 100
Steamfast 462.5 ±24.6 82.7 ±0.8 100 100 100
Steamax 428.0 ±22.8 81.5 ±1.9 100 100 100
Statistics F2,15 =3.1 F2,15 =0.2 – – –
P=0.074 P=0.803
†In the first test, only the mattress surface was steamed.
‡In the second test, the mattress surface and the floor of the plastic tray directly under and around the mini mattress were steamed.
Table 3. Mean (±standard error) temperature under the cover during steam treatment of bed bugs hiding under a fabric or leather cover
Temperature during egg treatment (∘C)†Temperature during nymph and adult treatment (∘C)‡
Cover type Steamer 15-s steam treatment 30-s steam treatment 15-s steam treatment 30-s steam treatment
Bed sheet HAAN 79.2 ±3.1 80.1 ±4.1 78.2 ±1.3 72.6 ±3.9
Steamfast 66.7 ±2.7 64.0 ±3.3 65.9 ±1.9 60.4 ±3.9
Steamax 75.7 ±3.2 76.1 ±0.6 73.0 ±1.3 75.2 ±0.6
Sofa fabric HAAN 70.2 ±4.6 79.1 ±2.2 63.5 ±4.6 82.3 ±0.4
Steamfast 67.0 ±4.0 79.0 ±2.4 59.3 ±3.5 72.2 ±2.7
Steamax 61.3 ±2.3 67.0 ±2.4 57.6 ±1.6 63.6 ±1.6
Sofa leather HAAN 39.4 ±0.3 37.7 ±1.6 35.4 ±2.0 31.7 ±0.4
Steamfast 36.8 ±0.7 36.7 ±1.3 32.5 ±2.3 30.7 ±0.5
Steamax 41.0 ±0.6 44.6 ±3.0 39.6 ±3.1 36.7 ±0.3
†Three-way ANOVA: Fcover =215.2, df =2102, P<0.001; Fsteamer =5.3, df =2102, P=0.007; Ftreatmentduration =4.0, df =1102, P=0.047.
‡Three-way ANOVA: Fcover =231.8, df =2102, P<0.001; Fsteamer =7.5, df =2102, P=0.001; Ftreatmentduration =2.3, df =1102, P=0.136.
The temperatures beneath the various covers were: bed
sheet (60.4–78.2 ∘C) =sofa fabric (57.6–82.3 ∘C) >sofa leather
(30.7–39.6 ∘C) (Tukey’s HSD test, P<0.05). The HAAN steamer
(31.7–82.3 ∘C) produced a significantly higher temperature under
the cover than the Steamfast steamer (30.7– 72.2 ∘C) (Tukey’s HSD
test, P<0.05).
Bed bug mortality was influenced by the cover type (egg mor-
tality: F=368.5, df =2102, P<0.001; nymph mortality: F=320.9,
df =2102, P<0.001; adult mortality: F=429.0, df =2102,
P<0.001), but not by the steamer or treatment duration (Tukey’s
HSD test, P>0.05). Therefore, we combined the data for different
steamers and treatment durations (Fig. 4). The egg mortality
under different cover types was: bed sheet >sofa fabric >sofa
leather. Mortality of nymphs and adults under sofa leather was
significantly lower than that under the bed sheet and sofa fabric.
3.3 Treating bed bugs hiding in a crack
In the bed bug egg treatments, the mean temperature in the cracks
was significantly affected by treatment duration (F=4.6, df =4, 38,
P=0.004), but not by steamer (F=0.6, df =2, 38, P=0.574). The
2-, 4-, 6-, or 8-s steam treatment created a significantly higher tem-
perature than the 1-s steam treatment (Tukey’s HSD test, P<0.05;
Fig. 5). There were no significant differences in the mean temper-
ature among the 2-, 4-, 6-, and 8-s steam treatments (Tukey’s HSD
test, P>0.05; Fig. 5).
During bed bug nymph and adult treatments, the mean temper-
ature in the cracks was significantly influenced by steamer (F=7.0,
df =2, 38, P=0.003) and treatment duration (F=12.6, df =4, 38,
P<0.001). The Steamax treatment induced significantly higher
temperatures in cracks than Steamfast (Tukey’s HSD test, P<0.05);
there was no significant difference in temperature between HAAN
and Steamfast, or between HAAN and Steamax (Tukey’s HSD test,
P>0.05). The 2-, 4-, 6-, and 8-s steam treatment durations induced
significantly higher temperatures in the cracks than the 1-s steam
treatment (Fig. 5). There were no significant differences in temper-
ature among the 2-, 4-, 6-, and 8-s steam treatments (Fig. 5).
Two-way ANOVA showed a significant effect of treatment dura-
tion on the mortality of bed bug eggs and adults, but not
nymphs (egg mortality: F=3.3, df =4, 38, P=0.021; adult mor-
tality: F=3.7, df =4, 38, P=0.012). The steamer type had no
significant effect on bed bug mortality (all P>0.05). Therefore,
we combined the data from different steamers for comparing
treatment durations (Fig. 5). The 4-, 6-, and 8-s treatment dura-
tions caused significantly higher egg and adult mortality than the
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Figure 4. Effect of the cover on the steamer’s bed bug control efficacy.
Data represent combined results for three steamers and two treatment
durations (15 and 30 s). During steam treatment, bed bugs were located
under a fabric or leather cover. Different lowercase letters above the bars
indicated significant differences between treatments (one-way ANOVA;
P<0.05, Tukey’s HSD test).
1-s treatment. All eggs and adults were killed at 4-s and longer
treatment durations; however, 100% mortality of nymphs was only
achieved at 6-s treatment duration.
4 DISCUSSION AND CONCLUSIONS
The boiling point of water at 1 atm of pressure (sea level) is 100 ∘C,
which is much higher than the maximum lethal temperature to
kill bed bugs (52 ∘C).15– 17 Therefore, in theory, exposing bed bugs
to steam produced at a short distance from them will result in
their death immediately. It is important to note that, during steam
treatment, bed bugs (nymphs and adults) may initially be exposed
to a sublethal or non-lethal temperature and may escape the
steam treatment by moving away or dropping onto the floor.
This phenomenon was observed in our preliminary experiments.
Figure 5. Effect of treatment duration on mean temperature in cracks
during steam treatment and steamer’s bed bug control efficacy. During
steam treatment, bed bugs were hiding in a crack. Bars indicate bed bug
control efficacy. The line indicates the temperature in cracks during steam
treatment. Data represent combined results for three steamers. Different
lowercase letters above the bars indicate significant differences in bed bug
control efficacy between treatments; different uppercase letters above the
line indicate significant differences in the temperaturebet weentreatments
(one-way ANOVA; P<0.05, Tukey’s HSD test).
Therefore, caution must be practiced when conducting steam
treatment in naturally infested environments. Steaming both the
infested area and the areas under and/or around the infested area
will be critical to ensure bed bug control efficacy. The sequence
of steam treatments of infested furniture should be from bottom
up to reduce the probability of bed bugs falling off the treated
surfaces. In experiment 1, 100% bed bug mortality was achieved
when both the surface of the mattresses and the arena floor
directly under the mini mattresses were steamed.
In addition, our results verify that bed bugs under a cover can
also be successfully killed by steaming. When treating bed bugs
under a cover, the steam treatment efficacy was affected by cover
type, not by the type of steamer, even though higher temperatures
were produced by the HAAN steamer compared to with Steam-
fast and Steamax. This was because all steamers produced a lethal
temperature under the fabric covers (bed sheet: 60.4– 80.1 ∘C; sofa
fabric: 57.6– 82.3 ∘C). In our study, bed bugs were hiding 2.3 cm
below the cover. However, whether the consumer-grade steamers
can kill 100% of bed bugs hiding much deeper under the cover
remains to be determined. The temperature under sofa leather
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(30.7–44.6 ∘C) induced by all three steamers was below the mini-
mum lethal temperature (45 ∘C). No significant bed bug mortality
was observed. In fact, homeowners and pest management pro-
fessionals might be reluctant to steam leather furniture coverings.
Similarly, in the experiment treating bed bugs hiding in cracks, the
variations among steamers resulted in a significant difference in
the treatment temperature, but not a significant difference in bed
bug mortality. In experiments with bed bugs under a cover, the
temperatures varied significantly with the treatment duration in
the bed bug egg treatments, but were similar among treatment
durations in the bed bug nymph and adult treatments. These dif-
ferent results suggest that minute differences in application tech-
nique can cause significant differences in the temperature deliv-
ered. However, overall, the temperature measurement results indi-
cate that temperatures lethal to bed bugs under fabric covers are
achieved if sufficient treatment time is used.
During our study, we found that once water vapor had con-
densed over a fabric cover, it became less conducive to steam
passing through. Thus, during indirect exposure treatment (bed
bugs hiding under a fabric cover), moving the steamer attachment
slowly across the surface of the cover is essential to ensure bed
bug control efficacy. Steam treatment failed to cause any mortal-
ity of bed bugs hiding under leather because of the inability of
the steam to pass through leather. In a domestic environment, bed
bugs may hide under many different materials, such as paper, card-
board, plastic, various fabrics and carpets. Studies on additional
types of covers would be beneficial to gain better understanding
of the efficacy of steam treatment.
In practice, a steamer’s effectiveness for killing bed bugs can be
affected by how fast steam is released and the attachment type
being used. The steamer Steamax has three working pressures.
To avoid blowing bed bugs off the mattress surface, we used
the medium pressure to treat bed bugs on the mattress surfaces
(experiment 1) and high pressure for steaming the bed bugs that
were hiding under a cover and in cracks. Commercial steamers
are equipped with different styles of attachments. Larger brush
attachments often work better than smaller tips, because the
smaller ones may release steam too fast, which can blow bed bugs
off the substrate.21
In conclusion, steam treatment can serve as an important com-
ponent of the IPM tool box for bed bug management. In this labo-
ratory study, steamers at affordable prices achieved the same high
control efficacy as the expensive steamer when properly used. This
finding provides evidence that, for home owners, using afford-
able steamers instead of spraying insecticides could achieve high
control efficacy. During steam treatment, it is critical to move the
steamer attachment slowly, and to extend the treatment duration
when treating bed bugs hiding in/under cracks or covers.
Self-treatment for bed bugs is common among people experi-
encing bed bug activity in their homes, and often involves the
purchase and application of insecticides. It is worth noting that
the insecticides purchased are expensive [for example, the Hot
Shot Bed Bug and Flea Killer (17.5 oz; Spectrum Group, St. Louis,
MO, USA) retails at $7.71, and the Pronto Plus Bedbug and Dust
Mite Killer (10 oz; Insight Pharmaceuticals Corp., Langhorne, PA,
USA) retails at $24.27; price information was obtained from https://
www.amazon.com] and are typically ineffective.27 Furthermore,
insecticide misapplication, including over-application, is likely to
cause potential hazards, such as the occurrence of insecticide resis-
tance and threats to human health. Our results demonstrate that
consumer-grade steamers offer an effective and affordable solu-
tion to replace the use of insecticides, which are less effective and
potentially harmful when applied by consumers in a manner that is
inconsistent with label directions for use. Consumer-grade steam-
ers have shorter operating times than the professional steamers;
however, because they are only being used for personal and not
commercial use, this is not a significant limitation. Therefore, this
non-chemical treatment technique is highly effective and advan-
tageous compared with the traditional chemical treatment as it
avoids the potential health risks of insecticide applications. Fur-
ther studies under various field conditions need to be conducted
to confirm its efficacy for eliminating bed bugs hiding in various
habitats.
ACKNOWLEDGEMENTS
We thank Qi Zhang for help in rearing bed bugs and Jeff White
for providing mini mattresses. HAAN Corporation and Steamfast
donated steamers. The study was supported by the USDA National
Institute of Food and Agriculture Hatch project 1001098 through
the New Jersey Agricultural Experiment Station, Hatch project
NJ08127. The senior author was also supported by the State
Scholarship Fund of China. This is New Jersey Experiment Station
Publication No. D-08-08127-07-17.
REFERENCES
1 Usinger R ed, Monograph of Cimicidae (Hemiptera: Heteroptera).Ento-
mological Society of America, College Park, MA (1966).
2 Doggett SL, Dwyer DE, Penas PF and Russell RC, Bed bugs: clinical
relevance and control options. Clin Microbiol Rev 25:164 –192 (2012).
3 Koganemaru R and Miller DM, The bed bug problem: past, present, and
future control methods. Pestic Biochem Phys 106:177 –189 (2013).
4 Romero A, Potter MF, Potter DA and Haynes KF, Insecticide resistance in
the bed bug: a factor in the pest’s sudden resurgence?JMedEntomol
44:175– 178 (2007).
5 ZhuF,WiggintonJ,RomeroA,MooreA,FergusonK,PalliRet al.,
Widespread distribution of knockdown resistance mutations in the
bed bug, Cimex lectularius (Hemiptera: Cimicidae), populations in
the United States. Arch Insect Biochem 73:245 –257 (2010).
6 Dang K, Doggett SL, Veera Singham G and Lee CY, Insecticide resistance
and resistance mechanisms in bed bugs, Cimex spp. (Hemiptera:
Cimicidae). Parasites Vectors 10:318 (2017).
7 Wang C and Cooper R, Environmentally sound bed bug management
solutions, in Urban Pest Management: An Environmental Perspective,
ed. by Dhang P. CAB International, Wallingford, pp. 44–63 (2011).
8 Tang J, Mitcham E, Wang S and Lurie S eds, HeatTreatments for Posthar-
vest Pest Control: Theory and Practice. CABI, Wallingford (2007).
9 Mahroof R, Subramanyam B and Flinn P, Reproductive performance
of Tribolium castaneum (Coleoptera: Tenebrionidae) exposed to the
minimum heat treatment temperature as pupae and adults. JEcon
Entomol 98:626– 633 (2005).
10 Massa R, Panariello G, Pinchera D, Schettino F, Caprio E, Griffo R
et al., Experimental and numerical evaluations on palm microwave
heating for Red Palm Weevil pest control. Sci Rep 7:45299 (2017).
11 Oliver-Villanueva JV, Gascón-Garrido P and Ibiza-Palacios MS, Evalua-
tion of thermally-treated wood of beech (Fagus syl vat ica L.) and ash
(Fraxinus excelsior L.) against Mediterranean termites (Reticulitermes
spp.). Eur J Wood Wood Prod 71:391 –393 (2013).
12 Uzunovic A, Gething B, Coelho A, Dale A, Janowiak JJ, Mack R et al.,
Lethal temperature for pinewood nematode, Bursaphelenchus
xylophilus, in infested wood using radio frequency (RF) energy. J
Wood Sci 59:160–170 (2013).
13 Pereira RM, Koehler PG, Pfiester M and Walker W, Lethal effects of
heat and use of localized heat treatment for control of bed bug
infestations. J Econ Entomol 102:1182–1188 (2009).
14 Johnson CG, The ecology of the bed-bug, Cimex lectularius L., in Britain.
JHyg41:345 –461 (1941).
15 Kells SA, Nonchemical control of bed bugs. Am Ent 52:109 –110 (2006).
16 Kells SA and Goblirsch MJ, Temperature and time requirements for
controlling bed bugs (Cimex lectularius) under commercial heat
treatment conditions. Insects 2:412– 422 (2011).
Pest Manag Sci (2018) © 2018 Society of Chemical Industry wileyonlinelibrary.com/journal/ps
www.soci.org D Wang et al.
17 Pinto LJ, Cooper R and Kraft SK, Bed Bug Handbook: The Complete Guide
to Bed Bugs and their Control. Pinto & Associates, Inc., Mechanicsville,
VA (2007).
18 Naylor RA and Boase CJ, Practical solutions for treating laundry
infested with Cimex lectularius (Hemiptera: Cimicidae). JEcon
Entomol 103:136– 139 (2010).
19 Cooper R, Chapter 8 - Ectoparasites, part three: bed bugs and kissing
bugs, in Mallis Handbook of Pest Control, 10th edn, ed. by Mallis A,
Hedges S and Moreland D. The Mallis Handbook Company, Richfield,
Ohio, pp. 587– 632 (2011).
20 Loudon C, Rapid killing of bed bugs (Cimex lectularius L.) on sur-
faces using heat: application to luggage. Pest Manag Sci 73:64– 70
(2017).
21 Potter MF, Romero A and Haynes KF, Battling bed bugs in the USA, in
Proceedings of the Sixth International Conference on Urban Pests,ed.
by Robinson WH and Bajomi D. OOK-Press Kft., Veszprém, Hungary,
pp. 401– 406 (2008).
22 Puckett RT, McDonald DL and Gold RE, Comparison of multiple steam
treatment durations for control of bed bugs (Cimex lectularius L.).
Pest Manag Sci 69:1061 –1065 (2013).
23 Wang C, Gibb T and Bennett GW, Evaluation of two least toxic inte-
grated pest management programs for managing bed bugs (Het-
eroptera: Cimicidae) with discussion of a bed bug intercepting
device. J Med Entomol 46:566 –571 (2009).
24 Wang C, Singh N, Cooper R, Liu C and Buczkowski G, Evaluation of an
insecticide dust band treatment method for controlling bed bugs. J
Econ Entomol 106:347 –352 (2013).
25 Abbott WS, A method of computing the effectiveness of an insecticide.
J Econ Entomol 18:265 –267 (1925).
26 IBM Corporation ed, IBM SPSS Statistics Base 22.IBMCorporation,
Armonk, NY (2013).
27 Wang C, Singh N and Cooper R, Efficacy of an essential oil-based
pesticide for controlling bed bug (Cimex lectularius) infestations in
apartment buildings. Insects 5:849–859 (2014).
wileyonlinelibrary.com/journal/ps © 2018 Society of Chemical Industry Pest Manag Sci (2018)