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Toxicities of Selected Essential Oils, Silicone Oils, and Paraffin Oil against the Common Bed Bug (Hemiptera: Cimicidae)


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The common bed bug [Cimex lectularius L. (Hemiptera: Cimicidae)] and tropical bed bug [Cimex hemipterus F. (Hemiptera: Cimicidae)] resurged in the United States and many other countries over the past decades. The need for safe and effective bed bug control products propelled the development of numerous 'green insecticides', mostly with essential oils listed as active ingredients. Various inorganic and organic oils also were used for bed bug management. However, there are no published studies on their toxicities against bed bugs. In this study, we screened 18 essential oils, three silicone oils, and paraffin oil (C5-20 paraffins) for their toxicities against bed bugs. All the oils exhibited insecticidal activity in topical assays. Their toxicities varied significantly; all of the evaluated essential oils were less effective than silicone oils and paraffin oil. The LD50 values of the most effective essential oil (blood orange), paraffin oil, and the most effective silicone oil (dodecamethylpentasiloxane) are 0.184 ± 0.018, 0.069 ± 0.012, and 0.036 ± 0.005 mg per bug, respectively. Direct spray of 1% water solution of 3-[hydroxy (polyethyleneoxy) propyl] heptamethyltrisiloxane, the only silicone oil that mixes well with water, resulted in 92% bed bug mortality after 1 d. Results of this study indicate silicone oils and paraffin oil have the potential to be used as safer alternative bed bug control materials.
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Toxicities of Selected Essential Oils, Silicone Oils, and
Paraffin Oil against the Common Bed Bug (Hemiptera:
ChenZha1,3, ChangluWang1, and AndrewLi2
1Department of Entomology, Rutgers University, New Brunswick, NJ 08901, 2USDA, ARS, Invasive Insect Biocontrol and Behavior
Laboratory, Beltsville, MD 20705, and 3Corresponding author, e-mail:
Subject Editor: Murray Isman
This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or a
recommendation by the USDA for its use. USDA is an equal opportunity provider and employer.
Received 9 May 2017; Editorial decision 18 September 2017
The common bed bug [Cimex lectularius L. (Hemiptera: Cimicidae)] and tropical bed bug [Cimex hemipterus
F. (Hemiptera: Cimicidae)] resurged in the United States and many other countries over the past decades. The
need for safe and effective bed bug control products propelled the development of numerous ‘green insecticides’,
mostly with essential oils listed as active ingredients. Various inorganic and organic oils also were used for bed
bug management. However, there are no published studies on their toxicities against bed bugs. In this study, we
screened 18 essential oils, three silicone oils, and paraffin oil (C5-20 paraffins) for their toxicities against bed bugs.
All the oils exhibited insecticidal activity in topical assays. Their toxicities varied significantly; all of the evaluated
essential oils were less effective than silicone oils and paraffin oil. The LD50 values of the most effective essential
oil (blood orange), paraffin oil, and the most effective silicone oil (dodecamethylpentasiloxane) are 0.184±0.018,
0.069 ± 0.012, and 0.036 ± 0.005 mg per bug, respectively. Direct spray of 1% water solution of 3-[hydroxy
(polyethyleneoxy) propyl] heptamethyltrisiloxane, the only silicone oil that mixes well with water, resulted in 92%
bed bug mortality after 1 d.Results of this study indicate silicone oils and paraffin oil have the potential to be used
as safer alternative bed bug control materials.
Key words: Cimex lectularius, essential oil, paraffin oil, silicone oil, toxicity
The common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae),
is an obligate blood feeder, which resurged world-wide in recent
decades (Doggett et al. 2004, Davies et al. 2012). Another similar
pest species, the tropical bed bug [Cimex hemipterus F. (Hemiptera:
Cimicidae)], was also recently documented in Florida after being
absent in over six decades (Campbell et al. 2016). Treatment with
insecticides is frequently used by professional pest controllers as well
as residents in an attempt to eliminate bed bug infestations. In a
senior citizen occupied building in Indiana, 40% of the 40 inter-
viewed residents indicated they self-applied insecticides for bed bug
control (Wang et al. 2010), while 89% of 18 interviewed residents
treated bed bugs on their own in another study in New Jersey (Wang
et al. 2014). Professional products such as Temprid SC (21% imi-
dacloprid + 10.5% β-cyuthrin; Bayer Environmental Science,
Research Triangle Park, NC), Suspend SC (4.75% deltamethrin;
Bayer Crop Science, Research Triangle Park, NC), and Demand CS
(9.7% λ-cyhalothrin; Syngenta Crop Protection, Greensboro, NC)
are widely utilized by licensed pesticide applicators in the United
States. In addition to professional insecticide products, the major-
ity of commercially available consumer bed bug control insecticides
on the U.S. market are also pyrethrins or pyrethroids, with a few
exceptions like silica gel and diatomaceous earth dusts (Wang et al.
2014). The effectiveness of pyrethrins and pyrethroids against bed
bugs is sometimes questionable, due to the wide-spread resistance to
pyrethroids among bed bug populations (Romero et al. 2007, Zhu
et al. 2010, Davies et al. 2012). Besides pyrethrins and pyrethroids,
many essential oil-based products, that is, ‘green insecticides’, for
controlling bed bugs have been developed in recent years. The con-
cept of green insecticide refers to all types of natural-oriented pest
control materials (Koul et al. 2008). One of the reasons companies
develop product lines with essential oils as green insecticides is that
many products are exempt from the requirements of the Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRA) under the mini-
mum risk exemption regulations (US EPA 2015); therefore, manu-
facturers do not need to pay expenses for US EPA registration and
they can get their product to market quicker and are exempt from
Journal of Economic Entomology, 111(1), 2018, 170–177
doi: 10.1093/jee/tox285
Advance Access Publication Date: 6 December 2017
Research Article
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EPA regulation. As EPA exempt products, federal registration is not
required, and many of these products are ineffective against bed bugs.
Out of 11 tested essential oil-based insecticides and detergents, only
EcoRaider bed bug killer (1% geraniol + 1% cedarwood oil + 2%
sodium lauryl sulfate; Reneotech, Inc., North Bergen, NJ) and Bed
Bug Patrol (0.003% clove oil + 1% peppermint oil + 1.3% sodium
lauryl sulfate; Nature’s Innovation, Inc., Buford, GA) caused > 90%
mortality to bed bug nymphs when using direct spray evaluation
(Singh et al. 2014). In a eld study, EcoRaider caused similar bed bug
population reduction as Temprid SC and EcoRaider + Temprid SC
mixture spray (Wang et al. 2014). The different efcacies among the
essential oil-based products indicate the necessity for further investi-
gation of the relative toxicity of individual essential oils.
Numerous essential oils are shown to be effective against insect
pests in laboratory and eld assays and used for pest control.
For example, thyme and peppermint are used to control green-
house whiteies [Trialeurodes vaporariorum Westw. (Hemiptera:
Aleyrodidae)] (Aroiee et al. 2005). Eucalyptus oil is effective in
killing or repelling insects such as Culex pipiens L. (Diptera:
Culicidae) (Erler etal. 2006), Tribolium confusum Duv. (Coleoptera:
Tenebrionidae), Ephestia kuehniella Zell. (Lepidoptera: Pyralidae)
(Tunc et al. 2000), and Sitophilus zeamais Motsch. (Coleoptera:
Curculionidae) (Ngamo etal. 2003). Essential oils also have poten-
tial in structural and household pest management. Polyethylene gly-
col–coated nanoparticles loaded with garlic essential oil is effective
against red our beetle [Tribolium castaneum Herbst. (Coleoptera:
Tenebrionidae)] (Yang etal. 2009). Phillips etal. (2010) evaluated the
toxicities of 12 essential oils against German cockroaches [Blattella
germanica L.(Blattodea: Blattellidae)] and found thymol and trans-
cinnamaldehyde to be the most effective. Various terpenoid compo-
nents in essential oils are responsible for the toxicity against insects;
for example, thymol and carvacrol, the two components of thyme
oil showed high insecticidal activity against Alphitobius diaperinus
Panz. (Coleoptera: Tenebrionidae) when applied alone (Szczepanik
etal. 2012). Limonene from citrus extract is effective against mealy-
bugs and scale insects (Hollingsworth 2005). Piperitone and trans-
ethyl cinnamate isolated from the essential oil of Artemisia judaica
L.showed pronounced insecticidal and antifeedant activity against
Spodoptera littoralis Boisd. (Abdelgaleil et al. 2008). Neem oil is
not, strictly speaking, an essential oil but a xed vegetable oil but
is also included in our screening process since it has been widely
used in pest management. Neem oil has been used for decades to
control pests such as brown planthopper (Nilaparvata lugens Stål
[Hemiptera: Delphacidae]), black bug (Scotinophara lurida Burm.
[Hemiptera: Pentatomidae]), and earhead bug (Leptocorisa acuta
Thunb. [Hemiptera: Alydidae]) (Isman etal. 1990, Schmutterer 1990,
Lokanadhan etal. 2012). Azadirachtin, a complex tetranortri-terpe-
noid limonoid from the neem seeds, is the main component respon-
sible for both antifeedant and toxic effects in insects (Nisbet 2000).
Many silicone oils are chemically stable and safe materials, com-
monly used in many daily necessities and medications that make dir-
ect contact to the human body. Silicone oil can be used in shampoo
(Hössel etal. 2000), skin cream (Sawada and Sone 1990), industrial
fermentation (Ates etal. 2002), and even cooking (Dana and Saguy
2006). Silicone oil is used in coating surfaces of various medical
equipments (e.g., syringes and stoppers) (Jones etal. 2005). Silicone
oil injections are common in vitreous microsurgery (Cox etal. 1986).
Interestingly, silicone oils also have some properties that make
them an excellent candidate for insecticides. These oils are generally
considered as unreactive and safe to humans. Many silicone oils are
light in weight, odorless, and colorless, which make them easy to
apply with little issue of clogging, staining, and smelling. Some sili-
cone oils are water soluble and used as surfactants.
The toxicity of certain silicone oils against insects has been deter-
mined in previous studies. Asilicone oil, Silwet L-77 (Helena Chemical
Co., Collierville, TN), a non-ionic surfactant, has been proven to be
effective against multiple agricultural pests (Imai etal. 1995, Purcell
and Schroeder 1996, Tipping etal. 2003). A few other trisiloxane
surfactants have insecticidal activity against two spotted spider mite
(Cowles et al. 2000). Despite the fact that silicone oils themselves
may have insecticidal activities, they are more often listed as inert
ingredients in insecticide formulations (Knoche 1994). Besides agri-
cultural use, silicone oils have been applied on human ectoparasites
as well. Dimeticone is found to be effective against head lice (Burgess
2009, Heukelbach etal. 2010). Asilicone oil-based commercial prod-
uct, Nopucid Bio Citrus (Laboratorio ELEA, Argentina) that contains
dimethicone, ciclopentaxiloxane, and bergamot essential oil, can
cause 100% mortality in head lice after exposed for 1min (Gallardo
etal. 2012). Therefore, it is plausible that certain silicone oils could be
effective against bed bug, which is also a human ectoparasite.
Parafn oil (C5-20 parafns) is a transparent, colorless, and odor-
less mineral oil. Similar to silicone oil, parafn oil is frequently found in
commonly used products such as lamp oil. Although the toxicity of par-
afn oil against insects is still unknown, the use of other mineral oils in
pest management has been tested in previous research. Sprays of Luxan
Oil H (93% mineral oil) and synthetic insecticides mixtures inhibited
the spread of aphid-born nonpersistently transmitted lily symptom-
less virus and lily mottle virus in Lilium L.(Liliales: Lilieae) (Asjes and
Blom-Barnhoorn 2000). Spray application of a mineral oil, Orchex 796
(Exxon, Houston, TX), provided additional control to codling moth and
secondary pests on apple, although the benet was hard to detect when
the pest density was high (Fernandez etal. 2005). Besides agricultural
use, petroleum-derived mineral oils are also effective against ectopara-
sites such as mites and lice; Wolf etal. (2016) found a mineral oil-based
head lice shampoo to be a safe and effective alternative for insecticide-
based pediculicides. Therefore, there is a potential of using mineral oils
in bed bug control. Among all the different mineral oils, parafn oil was
chosen in our study to evaluate toxicity against bed bugs, because it is a
light oil and will have less likelihood to stain mattresses, furniture, and
other personal belongings compared to heavieroils.
In this study, 18 different essential oils, 3 silicone oils, and par-
afn oil were tested in the laboratory for their toxicities against bed
bugs. Among the essential oils chosen for the study, cedarwood and
palmarosa (geraniol) are active ingredients of EcoRaider; ve dif-
ferent cedarwood oils were included because the species of cedar-
wood for extracting the oil used in EcoRaider is undisclosed by the
manufacturer. The other essential oils are also readily available and
have shown toxicities against insects in previous studies, as listed in
Table1. One silicone oil (dodecamethylpentasiloxane) is listed in
a bed bug control product as inert ingredients (BestYet, Cedarcide
Industries, Inc., Spring, TX), the other silicone oil (cyclopentasilox-
ane) is similar to dodecamethylpentasiloxane in viscosity, and the
last one (3-[hydroxy(polyethyleneoxy)propyl]heptamethyltrisilox-
ane) is listed in a developing formula (Siltech Corporation, Inc.,
Toronto, Ontario, Canada). These silicone oils exhibited high toxici-
ties against bed bugs in our preliminary studies. Our goal is to iden-
tify safe and effective alternative chemicals for controlling bedbugs.
Materials and Methods
In total, 18 essential oils, three silicone oils, and parafn oil were
included in the study (Table1). Essential oils vary considerably in
their composition depending upon where the plants were grown, the
season of harvest, the conditions prevailing during that year, and
even the manufacturer/supplier. The main constituents of oils listed
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in Table 1 were based on the Material Safety Data Sheet (MSDS)
provided by the manufacturer. If no MSDS from manufacturer was
available, the main constituents were obtained from related litera-
ture without listing their concentrations. An essential oil-based con-
sumer product, EcoRaider bed bug killer, also was used in this study
to compare against pure essential oils.
A eld strain of bed bug (Indy) was used in this study. It was collected
from multiple apartments during 2008 through 2009 in a building in
Indiana and was moderately resistant against pyrethroids (Singh et al.
2014). Bed bugs were maintained in plastic containers (5 cm diameter
and 4.7 cm height; Consolidated plastics, Stow, OH) with folded con-
struction paper (40 mm length and 30 mm width; Universal Stationers
Supply Co., Deereld, IL) as harborages and held at 26 ± 1°C, 40
± 10% relative humidity (RH), and a 12:12 (L:D) h photoperiod.
They were fed biweekly on debrinated rabbit blood (Hemostat
Laboratories, Dixon, CA) using a Hemotek membrane-feeding
system (Discovery Workshops, Accrington, United Kingdom). Bed
bugs were fed 1 wk prior to all experiments.
Experiment 1: Initial Screening of 22Oils
In total, 18 essential oils, 3 silicone oils, and parafn oil were screened
for their toxicities through topical assay. All oils were diluted to 0.2g/ml
in acetone. Adult male bed bugs of unknown age were used in this
experiment. Adroplet of 0.5µl liquid was delivered onto each bed bug’s
dorsal thorax by a hand micro-applicator (Burkard Manufacturing
Co. Ltd., Rickmansworth, Hertfordshire, United Kingdom), which
equaled to approximately 0.1-mg oil per bug. Treated bed bugs were
placed in groups of 10 on Fisherbrand P5 lter paper (3.5-cm diam-
eter; Fisher Scientic, Pittsburgh, PA) in a petri dish (5.5-cm diameter
and 1.5-cm height; Fisher Scientic). Each treatment was replicated
four times. Bed bugs in the control group were treated with acetone
with the same number of bugs and replications.
The treated bed bugs were kept in an incubator (Percival
Scientic, Inc., Perry, IA) at 25°C, a 12:12 (L:D) h light cycle, and
Table1. Essential oils, silicone oils, and paraffin oil tested in experiment1
Oil name Source plant Country of
Main constituents and reference Manufacturer and registration
Anise star Illicium verum China 82.5% Anethole (Chang and Ahn 2002) New Direction Aromatics Inc.
(Mississauga, Ontario, Canada),
CAS 8007-70-3
Basil Sweet Ocimum basilicum, ct.
India 73.06% Methyl chavicol (estragole);
19.2% linalool (Chang etal. 2009)
New Direction Aromatics Inc.,
CAS 8015-73-4
Blood orange Citrus sinensis Italy 98% Limonene (Hollingsworth 2005) New Direction Aromatics Inc.,
CAS 8028-48-6
Cedarwood Atlas Cedrus atlantica Morocco 45.95% b-Himalachene1 New Direction Aromatics Inc.,
CAS 8000-27-9
Cedarwood Chinese Cupressus funebris China 14.75% Thujopsene; 10.19% a-cidrene;
10% cedrol
New Direction Aromatics Inc.,
CAS 8000-27-9
Cedarwood Himalayan Cedrus deodora India 50.04% Himalchene New Direction Aromatics Inc.
CAS 68991-36-6
Cedarwood Texas Juniperus ashei / mexicana United States 34% Thujopsenene; 26% cedrol New Direction Aromatics Inc.,
CAS 68990-83-0
Cedarwood Virginian Juniperus virginiana United States 22.53% Cedrol; 20.31% thujopsenene New Direction Aromatics Inc.,
CAS 8000-27-9
Eucalyptus Blue Mallee Eucalyptus polybractea Australia 87.40% 1,8-Cineole (Lee etal. 2004) New Direction Aromatics Inc.,
CAS 8000-48-4
Eucalyptus Dives Eucalyptus dives Australia 52.07% Piperitone (Abdelgaleil etal.
2008); 20.38% a-phellandrene
New Direction Aromatics Inc.
CAS 90028-48-1
Eucalyptus Lemon Eucalyptus citriadora China 82.1% Citronellal (Koul etal. 2008) New Direction Aromatics Inc.,
CAS 85203-56-1
Neem Azadirachta indica - Azadirachtin (Isman etal. 1990) Lotus Brands, Inc. (Twin Lakes, WI)
Oregano Origanum vulgare Hungary Carvacrol, thymol (Lambert etal. 2001) Puritan’s Pride, Inc. (Oakdale, NY)
Palmarosa Cymbopogon martinii var
India 83.8% Geraniol New Direction Aromatics Inc.,
CAS 8014-19-5
Peppermint Mentha × piperita L. India Menthol, menthone (Edris and Farrag
Puritan’s Pride, Inc.
Spearmint Mentha spicata China l-Carvone (Koul etal. 2008) New Direction Aromatics Inc.
Tea Tree Melaleuca alternifolia China 41.02% Terpinen-4-ol (Isman 2000) New Direction Aromatics Inc.,
CAS 68647-73-4
Thyme Thymus vulgaris Thymol, carvacrol (Szczepanik etal.
Envisage Essentials (Canton, GA)
Silicone oil 1 100% Dodecamethylpentasiloxane Clearco Products Co., Inc.
(Bensalem, PA). CAS 141-63-9
Silicone oil 2 100% Cyclopentasiloxane Clearco Products Co., Inc.
(Bensalem, PA). CAS 541-02-6
Silicone oil 3 90% 3-[Hydroxy(polyethyleneoxy)pro-
pyl] heptamethyltrisiloxane
Gelest, Inc. (Morrisville, PA),
CAS 67674-67-3
Parafn oil 100% C5-20 parafns Lamplight Farms Inc. (Menomonee,
WI), CAS 64771-72-8
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were observed at 1, 3, 5, 7, and 14 d post-treatment. The numbers
of dead and moribund bed bugs were recorded at each observation
period. Adead bug was dened as no signs of activity when gently
prodded with a pair of lightweight forceps. Amoribund bug was
dened as bug that still can move its’ appendages, when prodded,
but cannot turn over or walk. Both dead and moribund bugs were
included in mortality during analysis.
After the initial screening, the three silicone oils were tested again
using the same method at a lower dose (0.04mg oil per bug) to deter-
mine if there are signicant differences in toxicities among them.
Experiment 2: Evaluating LD50 of SelectedOils
Three oils (blood orange, parafn oil,and silicone oil 1)were included
in this experiment. Blood orange and silicone oil 1 were the most
effective oils in the respective category based on results of Experiment
1.Adult males and females of mixed ages were used in this experi-
ment. Tested solutions were applied to bed bugs using the same
method as in Experiment 1.Blood orange was diluted to 0.2, 0.3,
0.4, 0.5, and 0.6g/ml and equaled to doses of 0.1, 0.15, 0.2, 0.25,
and 0.3mg oil per bug, respectively. Parafn oil and silicone oil 1 was
diluted to 0.04, 0.08, 0.12, 0.16, and 0.2g/ml and equaled to doses of
0.02, 0.04, 0.06, 0.08, and 0.1mg oil per bug, respectively. Eight bed
bugs of unknown age (four males and four females) were used in each
treatment and each treatment had four replications. Bed bugs in the
control group were treated with acetone. Less number of bed bugs
and both sexes were used compared to other experiments due to the
limited number of adults in the laboratory colony during experiment.
After treatment, the bed bugs were maintained in the same man-
ner as in Experiment 1. The numbers of dead and moribund bed
bugs were recorded at 1, 3, and 14 d post-treatment. Both dead and
moribund bugs were included in mortality during analysis, and mor-
tality at day 3 was used to calculate LD50.
Experiment 3: Comparison of Different Cedarwood
Oils, Geraniol, and EcoRaider by TopicalAssay
This experiment was designed to investigate if the origin and source
of plants affects the efcacy of essential oils and to compare the ef-
cacy of formulated essential oils (EcoRaider) and individual essential
oil components. EcoRaider, ve cedarwood oils, and geraniol were
included in this experiment. The oils represented the two major
active ingredients in EcoRaider: cedarwood oil and geraniol. The
ve cedarwood oils were from different source plants and origins,
and they had different chemical components (Table1); three of the
ve “cedarwood oils” were actually not from Cedrus at all but other
genera of plants and consequently bear no similarity to cedar wood
oil sensu stricto. The type of cedarwood oil used in EcoRaider was
not disclosed by the manufacturer. Adroplet of 0.5-µl EcoRaider
(original product) or essential oils (0.2g/ml in acetone) were applied
onto bed bugs through topical assay, following the same method
described in Experiment 1.Bed bug mortalities were recorded at 1,
3, 5, and 7 d post-treatment. Bed bugs in the control group were
treated with acetone. After treatment, the bed bugs were held in the
same way as in Experiment1.
Experiment 4: Efficacy of Silicone Oil 3 Water
Solution Against Bed Bugs by DirectSpray
Silicone oil 3 was the only tested silicone oil which can be evenly
mixed with water without any surfactant. Bed bugs (10 males and
10 third to fth instar nymphs) were placed in a petri dish (5.5-cm
diameter and 1.5-cm height) lined with lter paper (3.5-cm diameter)
on the bottom and sprayed with 0.1, 0.5, and 1% silicone oil 3 water
solutions. The solutions were applied to insects using a Potter spray
tower (Burkard Scientic Ltd, Herts, United Kingdom) at the rate
of 4.07 mg/cm2 (1 gallon/1,000 ft2). Treated bed bugs were trans-
ferred to clean petri dishes after spray. Each treatment was replicated
three times, and water was used in the control. The bed bugs were
held in the same manner following treatment, as in Experiment 1.
Mortality of bed bugs was observed at 1 d post-treatment.
Statistical Analysis
The efcacies of different oils in Experiment 1 were compared by
Kruskal–Wallis Test because data of some tested groups were not
normally distributed even after transformation. Probit analysis was
applied to calculate LD50 values in Experiment 2. The mortalities
caused by different cedarwood oils and geraniol in Experiment 3
were compared by analysis of variance followed by Tukey’s HSD
Fig.1 Mortality of bed bugs after topically treated with different oils at the dose of 0.1mg oil per bug, arranged in order by mean rank scores. There was no
mortality in the control.
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test, the mortalities at 1 and 7 d after topical assay in each treatment
were compared by paired t-test. All analyses were performed using
SAS software version 9.3 (SAS Institute Inc. 2011).
Toxicities of 22 Oils Against BedBugs
Bed bug mortalities stabilized at 3 d after topical application of
selected oils; therefore, 3-d data were used for comparison. There
were signicant differences in the mean bed bug mortalities
(χ2=62.67; df=21; P<0.001), varying from 5±3% (spearmint)
to 100±0% (dodecamethylpentasiloxane) (Fig. 1). The three sili-
cone oils and the parafn oil had highest mean rank scores among
all the oils, and blood orange had the highest mean rank score
among all essential oils (Table2). There was no mortality in the
At the lower dose of 0.04mg per bug, the silicone oils 1 (dodeca-
methylpentasiloxane), 2 (cyclopentasiloxane), and 3 (3-[hydroxy
(polyethyleneoxy) propyl] heptamethyltrisiloxane) caused 65 ± 3,
25±7, and 33±3% mortality, respectively; the efcacies of the three
silicone oils were statistically different (χ2=8.10; df=2; P=0.017),
with a mean rank score of 10.5 for silicone oil 1, 3.8 for silicone oil
2, and 5.3 for silicone oil 3.There was no mortality in the control.
LD50 of SelectedOils
Because a few bugs that were knocked down at 1 d recovered at
3 d, only mortality data at 3 d were used in LD50 value analysis.
Dead or moribund bugs on day 3 were not recovered after day 14.
The LD50 values of blood orange, parafn oil, and silicone oil 1
were 0.184±0.018, 0.069±0.012, and 0.038±0.005mg per bug,
respectively (Table3). The relative toxicities of these three oils were
silicone oil 1>parafn oil>blood orange. There was no mortality
in the control.
Comparison of Different Cedarwood Oils, Geraniol,
and EcoRaider by TopicalAssay
The mortality at 1 d ranged from 15±8% (geraniol) to 50±14%
(cedarwood Chinese), there were no signicant differences
among the tested cedarwood oils, geraniol, and EcoRaider at 1
d (F= 1.65; df= 6, 21; P=0.182). From 1–7 d, the mortalities
in different essential oil treatments did not change signicantly
(Table4); on the other hand, the mortality in EcoRaider treatment
increased signicantly from 38 ±10% to 93± 5% (t =−4.16;
df= 3; P=0.025; Fig. 2). The mortality in EcoRaider treatment
was signicantly higher than other treatments at 7 d (F=9.38;
df=6, 21; P<0.001; Tukey’s HSD test, P<0.05). There was no
mortality in the control.
Efficacy of Silicone Oil 3 Water Solution Against Bed
Bugs by DirectSpray
Silicone oil 3 solution killed 15±5, 88±2, and 92±5% bed bugs
at the concentration of 0.1, 0.5, and 1% after 1 d in direct spray,
respectively. The mortalities after 7 d were 18±5, 90 ± 0, and
92±5% at the concentration of 0.1, 0.5, and 1%, respectively. There
was no mortality in the control.
All the tested oils showed some level of toxicity against bed bugs.
However, the toxicities of different oils varied according to oil type,
origin, and source plants. For example, there are different types of
cedarwood oils. The ve cedarwood oils included in our study were
from four origins, extracted from six different tree species, and had
different main constituents. The insecticidal constituents of many
plant extracts and essential oils are monoterpenoids (Negahban etal.
2007). Therefore, the constituents and concentrations of terpenoids
are more critical than the trade name of the essential oils; the efcacy
of oils with the same name from different sources or manufactur-
ers may vary signicantly, while different oils with similar chemical
constituents could be used as replacement for advantages in cost and
availability. Therefore, it is necessary to understand their differences
and clearly list the source plants and constituents when used for pest
management purposes. Further studies of the effectiveness of iso-
lated terpenoids against bed bug would benet the development of
essential oil-based insecticide products.
Our study revealed parafn oil and the three silicone oils were
ranked higher in toxicity than all the essential oils tested. Besides
higher toxicities, parafn oil and silicone oils have additional
advantages over essential oils as insecticides. Parafn and silicone
oils are generally odorless and colorless, while essential oils usually
have strong odors. Although the odors from essential oil are often
described as fragrant and pleasing, some of them might be unpleas-
ant and even irritating to some people due to personal preference.
Some essential oils, such as blood orange, are colored and may stain-
treated items. Parafn oil and silicone oils hold promise as safe and
effective alternative bed bug control materials.
Table2. Mean rank scores of the toxicities of different oils ranked
by Kruskal–Wallis test
Mean rank
score Oils Mean rank score
Silicone oil 1 83.0 Tea Tree 40.3
Silicone oil 3 81.0 Eucalyptus Blue
Silicone oil 2 79.0 Cedarwood Texas 35.5
Parafn oil 79.0 Cedarwood Atlas 32.8
Blood orange 66.0 Palmarosa 32.8
Cedarwood Chinese 57.0 Peppermint 27.1
Cedarwood Virginian 51.6 Eucalyptus Dives 26.5
Thyme 51.6 Neem 23.0
Oregano 44.8 Basil Sweet 20.8
Cedarwood Himalayan 43.8 Anise star 15.1
Eucalyptus Lemon 40.6 Spearmint 11.8
Table3. Probit analysis results of the tested oils
Oil nSlope±SE LD50 (95% CI) (mg/bug) χ2P
Blood orange 160 9.71±1.51 0.184 (0.166–0.202) 41.48 <0.001
Parafn oil 160 6.15±1.12 0.069 (0.060–0.081) 30.25 <0.001
Silicone oil 1 160 7.66±1.15 0.038 (0.032–0.043) 44.29 <0.001
174 Journal of Economic Entomology, 2018, Vol. 111, No. 1
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Previous studies suggested that silicone oils kill target insects by
physical means. Richling and Böckeier (2008) tested a dimeticone-
based pediculicide Nyda (G. Pohl-Boskamp GmbH & Co. KG,
Hohenlockstedt, Germany) against head lice [Pediculus humanus
capitis De Geer (Phthiraptera: Pediculidae)] and house crickets
[Acheta domestica (Linnaeus) (Orthoptera: Gryllida)] and con-
cluded that dimeticone was capable of entering the tracheal system,
with subsequent asphyxiation in insects. On the other hand, Burgess
(2009) suggested that a 4% dimeticone/96% cyclomethicone prod-
uct, Hedrin (Thornton & Ross Ltd, Hudderseld, United Kingdom),
killed lice by entering spiracles and tracheae of lice, which would
lead to disruption of water management, subsequent osmotic stress
and gut rupture. Although the mechanism of parafn oil has not
been discussed previously, some other petroleum-derived mineral
oils were thought to have a physical mode of action based on cover-
ing and suffocation of ectoparasites such as mites and lice (Agnello
2002, Taverner 2002, Wolf etal. 2016). The mode of action of sili-
cone and parafn oils against bed bug is probably similar, since
death occurred instantly after treatment, with no prolonged effect
observed. Further examination by microscopic tools such as scan-
ning electron microscope on bugs treated by silicone and parafn
oils may help us understand the modes of action of theseoils.
The different time-mortality patterns of EcoRaider compared
with individual essential oils suggest that by combining different
essential oils or using special formulating techniques, the efcacy of
essential oils can be signicantly increased. In experiment 3, compar-
ing different oils and EcoRaider, the total amount of active ingredi-
ents applied to each insect was much higher in the cedarwood oil and
geraniol treatments (0.2 g/ml in acetone) compared to EcoRaider
(1% geraniol + 1% cedarwood oil). Yet, EcoRaider resulted in much
greater mortality. The additional mortality after 7 d treatment in
the EcoRaider treatment also suggests that formulated essential
oils could have additional insecticidal effect beyond the initial kill
shortly after exposure. Many essential oils are known for their high
volatility (Negahban etal. 2007); terpenoids in oils may evaporate
soon after application, which explains why all essential oils tested in
the study alone did not show additional mortality over time. In the
case of EcoRaider, the additional slow killing effect and high efcacy
are probably a result of the interactions of multiple ingredients and
a special formulating process; one possible mode of action is that
surfactants damage the wax layer of insect cuticle and facilitated
the penetration of terpenoids through cuticle, which remain in the
body and cause prolonged death. Further studies on the interaction
of essential oils, silicone oils, parafn oil, and other inert ingredients
in insecticide formulations are warranted for developing more effect-
ive formulations based on various oils.
We thank Qi Zhang for bed bug colony maintenance. We also thank Dr.
Lena Brattsten at department of Entomology, Rutgers for providing us access
to the hand micro-applicator. This study was supported by the National
Institute of Food and Agriculture, U.S. Department of Agriculture Hatch
project 1001098, through the New Jersey Agricultural Experiment Station,
Hatch project NJ08127. This is New Jersey Experiment Station publication
Table4. Changes in mortalities at 1 and 7 d after topical assay in different oil treatments
Oil 1-d mortality% 7-d mortality% Paired t-test
Cedarwood Atlas 20.0±4.1 22.5±4.8 t=−0.52; df=3; P=0.638
Cedarwood Chinese 50.0±14.1 47.5±13.1 t=1.00; df=3; P=0.391
Cedarwood Himalayan 25.0±8.7 30.0±7.1 t=−1.73; df=3; P=0.182
Cedarwood Texas 25.0±11.9 22.5±12.5 t=1.00; df=3; P=0.391
Cedarwood Virginian 30.0±4.1 32.5±6.3 t=−1.00; df=3; P=0.391
Geraniol 15.0±5.0 17.5±6.3 t=−1.00; df=3; P=0.391
EcoRaider* 37.5±10.3 92.5±4.8 t=−4.16; df=3; P=0.025
*Signicant difference (paired t-test, P<0.05).
Fig.2 Mortality of bed bugs treated with different cedarwood oils, geraniol, and EcoRaider at the dose of 0.1mg oil or 0.5µl EcoRaider original solution per bug.
There was no mortality in the control.
175Journal of Economic Entomology, 2018, Vol. 111, No. 1
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... Thymol was reported as having repellent activity against Blatella lateralis (Walker) (Blattodea: Blattidae) [24]. In bed bugs, several studies have evaluated the contact toxicity [27][28][29][30][31], fumigant toxicity [29,32,33], and residual toxicity [34,35] of plant-derived pesticides, but few have studied in detailed their repellency. Anderson et al. [36] demonstrated the efficacy of three naturally occurring repellents, para-menthane-3,8-diol, delta dodecalactone, and gamma dodecalactone to prevent bed bugs from hiding in substrate-treated areas. ...
... While essential oils and EOCs have demonstrated excellent contact and fumigant toxicity against bed bugs [29,32,35], there is still limited information on the repellency of these compounds when applied to personal belongings or directly to skin to protect a host from bites. However, skin-applied repellent products can be sticky and therefore not suitable for use before going to bed. ...
Full-text available
Botanical-derived pesticides have arisen as an attractive alternative to synthetic insecticides to effectively manage infestations of bed bugs (Cimex lectularius L.). While information on contact, residual, and fumigant toxicity of plant-essential oils against bed bugs have been recently published, there is a gap of information regarding the repellent activity of these products and their constituents. Identification of essential oil constituents (EOCs) with repellent activity will help develop potentially efficacious essential oil-based formulations for use in bed bug management programs. In this study, we first screened fresh and 24 h-aged residues of geraniol, eugenol, carvacrol, thymol, citronellic acid, linalool, menthone, trans-cinnamaldehyde, α-pinene, β-pinene, and limonene for avoidance behavior from individual bed bugs with a video-tracking system. Six EOCs, geraniol, eugenol, citronellic acid, thymol, carvacrol, and linalool were further evaluated overnight in choice tests to determine whether 24-h aged residues were still avoided by groups of bed bugs. While bed bugs avoided resting on filter papers treated with 24-h aged residues of geraniol, eugenol, citronellic acid, and carvacrol, bed bugs aggregated in areas treated with linalool-aged residues. Barriers of EOCs did not prevent bed bugs from reaching a warmed blood source and acquiring blood meals. Our results show that novel formulations of natural product insecticides that include geraniol, eugenol, carvacrol, or citronellic acid have potential to repel bed bugs. The presence of host-associated cues might interfere with these responses.
... Since modern formulations of petroleum oils are considered as biorational insecticides, their application sites have been further expanded, including greenhouses, aquatic areas and animal premises, or even residential premises such as commercial industrial or medical establishments (US EPA 2007). Hence, petroleum oils efficacy has been evaluated in a broad range of host plants and pest species, including fruits (Liu and Stansly 1994;Northover and Schneider 1996;Liang and Liu 2002), vegetables (Reddy and Bautista 2012), flowers and ornamental plants (Miller 1989;Larew and Locke 1990;Marcinek et al. 2018), industrial and forage crops (Mensah et al. 1995(Mensah et al. , 2005Kumar 2015), and pests species of health importance, such as mosquitoes (Micks 1970;Micks and Berlin 1970), bed bugs (Zha et al. 2018) and external parasites of livestock (USDA 2015). ...
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Paraffin (petroleum) oils have been used for many years for their insecticidal properties, but relatively little research had been conducted towards their introduction into the agricultural praxis, due to their potential phytotoxic effects. In the recent years, however, there has been an increased interest in petroleum-based pesticides due to their compatibility with integrated pest management (IPM) programs. Various improvements in the refinement methods have enhanced the manufacture of commercial products with many advantageous features over the original oil formulas. However, literature is still lacking of a general overview about the applicability of newly introduced commercial petroleum oils in agriculture and their compatibility with modern pest management practices. Therefore, the present work aims to depict the current status of petroleum oils in arboriculture and beyond, providing an in-depth analysis of their insecticidal properties with respect to the knowledge gained over the years about the factors responsible for the pesticidal efficacy and the phytotoxic activity of petroleum-derived oil insecticides. Moreover, commercial aspects of petroleum oil formulations and their toxicological profile to non-target organisms have also been addressed through the current legislation in EU and the USA.
... Simultaneously, the toxicity of essential oil and para n oil was investigated and compared with para n oil, where the research proved that para n oil was much more poisonous. Furthermore, a study demonstrated that the para nic component was considerably higher toxic than the crude oil [31,32]. Ginger (Zingiber o cinale) is commonly used in cooking as a condiment/spice and is also identi ed as herbal medicine (herb used to treat in ammatory and pain). ...
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The study aimed to evaluate the potential of ginger essential oil in urea loading efficacy to prepare the controlled release chitosan microspheres. The ginger oil was extracted by applying the Clevenger apparatus for hydro-distillation, and the chemical composition was characterized by using FT-IR. The chitosan microspheres and urea loaded were formulated through modified emulsification and followed cross-linking procedure. Response surface test was used to evaluate various factors and levels related to preparation of microspheres. The nitrogen content, yield were observed in the present study. Furthermore, SEM and FT-IR were applied to characterize the microspheres. The results showed that the yield of the ginger oil was 6.0% and citral was observed as the most enriched compound, 89.05% in oil. Response surface analysis showed that the optimum preparation conditions were as follows: 2.094% of Span-80, 2.302% of acetic acid, and the crosslinking agent ratio of formaldehyde to glutaraldehyde was 1:8.148. Under these conditions, the theoretical value of nitrogen content of urea-loaded chitosan microspheres was 4.683%. The FT-IR results proved the authenticity of ginger oil, chitosan microspheres, and urea-loaded microspheres. The morphology of the microspheres was better in lower oil concentrations. The release test showed urea diffused uniformly in the microspheres after 48 hours. It is concluded that controlled release fertilizers can be formulated using ginger oil.
... The breeding process was performed under a 12-h light and dark photoperiod at 25 ± 1 ! and a relative humidity of approximately 60% ± 5%, according to the method described by Feldlaufer et al 13 and Zha et al 14 . Breeding was performed to obtain a sufficient number of bugs for the insecticide evaluation experiments. ...
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Bed bugs, Cimex hemipterus (Hemiptera: Cimicidae) are small insects that are considered public health pests and cause many health and economic problems. The efficacy of Organophosphorus insecticides (Safrotin and Actikill) and pyrethroids (Project and Cyper Safe) in controlling C. hemipterus adults and nymphs were investigated using contact and dipping methods. The WHO protocol was followed for insecticides application. The results of the current study showed that the project pesticide from the pyrethroids group gave the highest effectiveness against bed bugs, as the value of the concentration that killed 50% (LC50) of insects was of the adults (264.8, 337.5 ppm) when using dipping and contact methods, respectively. while the LC50 value when applying the two methods of the same insecticide against nymphs was 254.7 and 329.3ppm, respectively. However, Safrotin the more effective organophosphorus insecticide. The dipping method was more effective than the contact method for all insecticides, and the nymphs were more susceptible than the adults (LC50= 1502.6 and 1065.28ppm). The pesticides can be arranged in descending order according to their effect as follows: Project> Cyper Safe > Safrotin > Actikill. Our findings suggest that bed bugs in Jeddah Province may have developed resistance to common pesticides used in public health pest management programs. For this reason, this study recommends a periodic evaluation of the effectiveness of pesticides to be used during emergency pest outbreaks
... We recently reported that bed bugs exhibiting metabolic and target site deltamethrin resistance (72,000-fold at the 25% mortality level) are susceptible to EOs and their major constituents (Gaire et al., 2020b). Similarly, numerous reports have documented efficacy of EOs, EO constituents or their mixtures against field-collected and laboratory populations of bed bugs (Feldlaufer and Ulrich, 2015;Singh et al., 2014;Politi et al., 2017;Zha et al., 2018;Gaire et al., 2019Gaire et al., , 2020a. However, the question as to whether plant EOs or their constituents can synergize or enhance pyrethroid toxicity in resistant bed bugs by inhibiting detoxification enzymes has remained unanswered. ...
Plant essential oils (EOs) are secondary metabolites derived from aromatic plants that are composed of complex mixtures of chemical constituents. EOs have been proposed as one of the alternative methods for bed bug (Cimex lectularius L.) control. In insecticide resistant mosquitoes and tobacco cutworm, EOs synergize pyrethroid toxicity by inhibiting detoxification enzymes. However, whether EOs and their constituents enhance pyrethroid toxicity in C. lectularius has remained unknown. Therefore, this study was designed to (i) determine the effects of binary mixtures of deltamethrin (a pyrethroid insecticide) with EOs or EO constituents or EcoRaider® (an EO-based product) on mortality of insecticide resistant and susceptible bed bugs, and (ii) evaluate the effects of EO constituent pre-treatment on detoxification enzyme activities of resistant and susceptible populations. Topical bioassays with binary mixtures of deltamethrin and individual EOs (e.g., thyme, oregano, clove, geranium or coriander oils) or their major constituents (e.g., thymol, carvacrol, eugenol, geraniol or linalool) or EcoRaider® at doses that kill approximately 25% of bed bugs caused significant increase in mortality of resistant bed bugs. However, in the susceptible population, only coriander oil, EcoRaider®, thymol, and carvacrol significantly increased the toxicity of deltamethrin. Detoxification enzyme assays with protein extracts from bed bugs pre-treated with EO constituents suggested selective inhibition of cytochrome P450 activity in the resistant population, but no impacts were observed on esterase and glutathione transferase activities in either population. Inhibition of P450 activity by EO constituents thus appears to be one of the mechanisms of deltamethrin toxicity enhancement in resistant bed bugs.
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Plant based natural products have been widely used as antibacterial and insect repellent agents globally. Because of growing resistance in bacterial plant pathogens and urban pests to current methods of control, combined with the long-and short-term negative impact of certain chemical controls in humans, non-target organisms, and the environment, finding alternative methods is necessary to prevent and/or mitigate losses caused by these pathogens and pests. The antibacterial and insect repellent activities of essential oils of novel cultivars of catnip (Nepeta cataria L. cv. CR9) and oregano (Origanum vulgare L. cv. Pierre) rich in the terpenes nepetalactone and carvacrol, respectively, were evaluated using the agar well diffusion assay and petri dish repellency assay. The essential oils exhibit moderate to high antibacterial activity against three plant pathogens, Pseudomonas cichorii, Pseudomonas syringae and Xanthomonas perforans of economic interest and the individual essential oils, their mixtures and carvacrol possess strong insect repellent activity against the common bed bug (Cimex lectularius L.), an urban pest of major significance to public health. In this study, the essential oils of catnip and oregano were determined to be promising candidates for further evaluation and development as antibacterial agents and plant-based insect repellents with applications in agriculture and urban pest management. (2023) Volatile metabolites from new cultivars of catnip and oregano as potential antibacterial and insect repellent agents.
The objective of this study was to review the studies used plants and plant components against Cimex lectularius. Standard procedure for systematic reviews was followed. Various electronic databases were investigated for choosing reliable researches from 1990 to 2021. In total, 18 papers were selected among the 300 papers. Totally, 26 plants were evaluated in the published studies. Plants included Thymus vulgaris, Origanum vulgare, Mentha piperita, Syzygium aromaticum, and plant components of Thymol, Carvacrol and Linalool have the highest frequency in the papers studied. Maximum mortality and repellency of up to 100% were reported for the essential oils of Tagetes patula, Schinus molle, and plants of Cinnamomum sp. Cymbopogon martinii, Mentha piperita, Salvia rosmarinus, Thymus vulgaris, Origanum vulgare, Nepeta cataria. The results of this review can provide a better understanding of the potential of extracts and essential oils made from these plants and plant components for researchers to control bed bugs.
Polyelectrolytes (polymers carrying positively or negatively charged groups) can be used as adjuvants in subunit vaccine formulations to increase the immunogenicity of antigenic molecules. A vaccine prototype can be obtained by covalently bonding antigenic molecules to polyelectrolytes or using their physical mixtures with polyelectrolytes. Covalent conjugates of polyelectrolytes with antigens are known to exhibit stronger immunogenicity compared to physical mixtures of antigens and polyelectrolytes. In this study, linear conjugates of polyacrylic acid (PAA) with an antigenic peptide sequence (STHVDIRTLEDLLMGW) of the HPV-16 E7 oncoprotein were produced. PAAs of different molecular weights with narrow dispersity were synthesized by RAFT polymerization. The linear conjugates of PAA and the peptide were obtained by covalent bonding via the chain-end thiol group of PAA and N-terminal maleimide group of the peptide using the maleimide-thiol reaction. For this purpose, the trithiocarbonate end group of the polymer was reduced with excess ethylenediamine to the thiol group. The produced PAA-peptide conjugates were characterized by GPC, fluorescence, and NMR spectroscopies. Conjugation efficiency was above 80% for all PAAs. Antigenic peptide conjugates of PAAs of different molecular weights were investigated in MTT and nitric oxide (NO) assays in which the linear PAA-peptide conjugates exhibit high biocompatibility and stimulated the macrophages to release high levels of NO.
Distribution of methylsiloxanes in environment is still far from being well studied. Little is known about the concentrations and associated risks of these chemicals in river-lake systems. This study investigated the occurrence of twelve methylsiloxanes (D4–D6, L5–L13) in the sediments from Lake Chaohu and its inflowing rivers, China, and found the total concentrations (ng/g dry weight) were in the range of 47.1–496 and 239–3593, respectively. Linear congeners were dominant, representing a median of 62.8% and 58.7% of the total concentrations found in the lake and its inflowing rivers, respectively. In general, the concentrations of sediment methylsiloxanes in the investigated river-lake system were low to moderate, compared with the results reported previously in other waters. Source assessment indicated that the emissions from industrial activities and the use of silicone-containing products were the main contributors of sediment methylsiloxanes in the investigated waters. D4 and D5 in 18.5% and 11.1% of river sediment samples might pose ecological risks to fish. The risks from the linear congeners in sediments in the area were not estimated due to no related benchmarks available. More studies are needed to investigate the occurrence of these chemicals and associated risks in aquatic environment.
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The most widely held theory on the mode of action of petroleum oils is that they act physically by blocking the spiracles. Presently, the most common use of insecticidal oils is as field sprays. The dominance of highly refined petroleum as spray oils has reinforced the premise that oils primarily kill by suffocation. Considerable evidence supports this theory, but, no single theory accounts for all circumstances. Closer observation reveals several theories regarding how oils kill arthropods, depending on physical characteristics of the oil. Heavy saturated oils penetrate a short distance into the tracheae to form physical barriers to gaseous exchange. In contrast, light oils containing a large amount of unsaturated hydrocarbons pass through the body cavity, dissolving the fat bodies and eventually the internal cellular structure. Thirdly, the highly volatile components of oils can act as narcotic fumigants. This discussion is a historical review of the insect toxicology of petroleum oils. Early contributions are considered in the context of the properties of the oils used at that time. Many studies report observations inconsistent with anoxia but few attempts have been made to resolve these differences and increase our knowledge of the mode of action of oils. More recent work on novel application methods, such as postharvest dipping with oils, are used to argue that a preoccupation with anoxia has limited the potential of oils as pesticides.
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This is the first report of the tropical bed bug in Florida in over 6 decades. The tropical bed bug had previously been documented in Florida in the 1930s and 1940s.
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Background: Due to increased resistance and safety concerns with insecticide-based pediculicides, there is growing demand for head lice treatments with a physical mode of action. Certain mineral oils kill lice by blocking spiracles or by disrupting the epicuticular wax layer. The present study was performed to evaluate efficacy and safety of a mineral oil-based shampoo. Methods: This randomized, controlled, investigator-blinded, monocentric study (EudraCT registration no. 2014-002918-23) was performed from October 2014-June 2015 in Germany. A mineral oil shampoo (Mosquito® Med Läuse Shampoo 10 in Germany, Paranix or Silcap shampoo elsewhere), registered as medical device, was compared to a conventional, locally reimbursed, pyrethroid-based pediculicide (Goldgeist® Forte solution). In total, 107 patients (>1 year) with confirmed head lice infestation were included (test arm: n = 53; control arm: n = 54). All subjects received two applications of either test or control product at day 0 and day 7, according to the instructions for use. Efficacy and safety was evaluated directly, 1h and 24h after first application, before and after second treatment, and at day 10. The main objective was demonstrating a cure rate for the test product, being superior to 70% at day 10. Results: Cure rates at day 10 (corrected for re-infestation) for the test product (96.1%) and control (94%) significantly exceeded the pre-defined target (70%) (p < 0.001, 2-sided, 1-sample, chi-square test) with confirmed non-inferiority for the test product. Over all visits, cure rates were consistently higher for the test product, whereas more initially-cured subjects remained lice-free until end of study (78%; control: 60%). Both products were safe and well tolerated, offering good esthetical effects. Conclusion: This study showed that substance-based medical devices (including the tested mineral oil shampoo) can be safe and effective alternatives for insecticide-based pediculicides, with less risk for development of resistance because of the physical mode of action. Trial registration: German Clinical Trials Register (DRKS) DRKS00009753 and EudraCT database 2014-002918-23.
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Bed bugs (Cimex lectularius L. and Cimex hemipterus F.) are among the most difficult urban pests to manage. Many essential oil-based bed bug control products that are considered reduced risk to mammals compared to synthetic insect neurotoxins have become commercially available, but their effectiveness as a stand-alone control method is unknown. This study assessed the field efficacy of an essential oil-based bed bug control product (EcoRaider; a.i. 1% geraniol + 1% cedar oil + 2% sodium lauryl sulfate) compared to a pyrethroid and neonicotinoid mixture spray (0.075% Temprid SC; a.i. beta-cyfluthrin + imidacloprid). After 12 weeks, the three treatments—EcoRaider, Temprid SC, and EcoRaider + Temprid SC caused 92.5 ± 2.7, 92.9 ± 3.0, and 91.7% ± 2.7% bed bug count reduction, respectively. No significant differences existed in the bed bug reduction among the treatments. Bed bugs were eliminated from only 22% of the treated apartments. Among those still with bed bugs, 76% of the residents did not know bed bugs were present. We documented the residents’ self-control practices and discussed the potential of using essential oil-based insecticides in bed bug management programs to minimize the health risks to building occupants and pets and to slow down the development of insecticide resistance.
"Rice is Life" for millions of people and staple food for more than half of the worlds' population. The demand for rice is growing with ever increasing population. At present the grain yield in rice has to be increased and the yield achieved has to be sustained. The field studies at Wetlands, Tamil Nadu Agricultural University Coimbatore resulted in compilation of agronomical use of neem and its by products in rice cultivation. The Wetland Farm at Agricultural College and Research Institute, Coimbatore is situated in the Western Agro Climatic Zone of Tamil Nadu at 11° North Latitude and 77°East Longitude at an altitude of 426.72 m above MSL. The properties of neem as insecticide, antifeedant, hormonal, antifungal, antiviral and nematicide properties is well known.These activities are brought out with neem use in the form of leaves, leaf extracts, seeds, cakes, oil and fruit extracts. The neem and its products are used in seed treatment, manurial application, increasing nutrient efficiency by which the grain yield in rice crop is enhanced and its sustainability is seen in rice based cropping system. Evaluation of these products in managing the rice crop, through agronomial cultural practices at various stages of crop growth has been discussed in detail in this paper.
The insecticidal activities of materials derived from the fruit of star anise, Illicium verum, against adults of Blattella germanica were examined by direct contact application and fumigation methods, and compared with those of DDVP, deltamethrin and hydramethylnon. The biologically active constituent of the Illicium fruit was characterized as the phenylpropene, (E)-anethole, by spectroscopic analysis. In a filter paper diffusion test with females, (E)-anethole caused 80.3% mortality at 0.159 mg cm(-2) at 1 and 3 days after treatment (DAT), whereas 16.7% mortality at 3 DAT was achieved at 0.079 mg cm(-2). DDVP and deltamethrin gave >90% mortality at 0.019 mg cm(-2) at 1 DAT. At 0.009 mg cm(-2), DDVP and deltamethrin showed 73.3 and 60% mortality at 1 DAT, respectively, but 93.3 and 76.7% mortality at 3 DAT. Hydramethylnon exhibited 0 and 93.3% mortality at 0.159 mg cm(-2) at 1 and 3 DAT, respectively, whereas 6.7% mortality at 3 DAT was observed at 0.079 mg cm(-2). In a fumigation test with females, (E)-anethole was much more effective in closed cups than in open ones, indicating that the insecticidal activity of the compound was largely attributable to fumigant action. (E)-Anethole and DDVP caused 100% mortality at 0.398 and 0.051 mg cm(-2) 4 and 1h after treatment, respectively. (E)-Anethole showed 46.7% mortality at 0.199 mg cm(-2) at 3 DAT, whereas deltamethrin and hydramethylnon at 0.796 mg cm(-2) was ineffective for 3-day period. As naturally occurring insect-control agents, the I verum fruit-derived materials described could be useful for managing populations of B germanica. (C) 2001 Society of Chemical Industry.