Repellency of selected chemicals against the bed bug

[Stewart Allen]

Dear Pilgrims,

Please see the attached article (2013) detailing scientifically validated experiments testing the effectiveness of different commercially available repellents against the common bed bug.

In short (and against the received wisdom on this forum that permethrin is most effective), the study found the following:

The two commercial repellent products that contained 7% picaridin or 0.5% permethrin had little repellency against bed bugs. N,N-diethyl-m-toluamide (DEET), the most commonly used insect repellent, provided a high level of repellency against bed bugs.

This is the first study addressing repellents for Cimex lectularius L. We found DEET and three compounds from Bedoukian Research Inc. are effective repellents against bed bugs. At 25% or higher concentration, DEET can prevent >94% bed bugs from crossing the treated area for at least 8 h under high pest pressure (i.e., hungry bed bugs and a strong host cue were present). The findings suggest that applying a repellent to luggage, shoes, or clothing could be an effective method to avoid bed bug infestations by home visitors, pest control technicians, travelers, and other personnel who need to visit or work in bed bug-infested environments.

I hope this helps, buena suerte!

 

[scikowski]

Does this mean that you would have to treat everything every day?

 

[Tincatinker]

Does this mean that you would have to treat everything every day?

Thats what it says. Spray everything with DEET, every day, to provide 94% protection for the 8 hours every day that you are likely to be lying in bed worrying about bedbugs.

 

[Stewart Allen]

Actually, the 94% figure refers to the percentage of bed bugs that the DEET prevents from crossing the treated area.

In answer to the original question, the article states that 25% DEET should last for 21 days, after which its effectiveness significantly drops:

"Longevity tests of 25% DEET showed its repellency started to decrease signiÞcantly after 21 d"

Not sure of the effect of DEET however on synthetic fabrics at these concentrations, might be worth investigating before applying to fabrics and plastics...

 

[jmcarp]

...
Not sure of the effect of DEET however on synthetic fabrics at these concentrations, might be worth investigating before applying to fabrics and plastics...

Not specifically relative to the types of synthetic fabrics typically found in the technical clothing many wear on the Camino, but FWIW, I had a small container of mosquito repellent containing DEET which I kept in the little plastic storage pocket on the inside of my car door. I didn't realize that the container had a leak until I noticed that the plastic storage pocket had begun to melt under the leaking bottle of insect repellent. True story.

 

[dougfitz]

Does this mean that you would have to treat everything every day?

The EPA factsheet on DEET (here) includes the advice to wash treated clothing before wearing it again. While they don't provide advice on equipment treated with DEET, this would clearly be impractical for sleeping bags and liners.

It is important to distinguish between DEET and picaridin on one hand, and permethrin on the other. Permethrin is an insecticide, and works by killing insects, which might take some time and allow them to have a last feed. DEET and picaridin are insect repellents and work by masking the signs like your smell that indicate that you might provide a good feed (to the insect).

In my experience, DEET and permethrin are companions in a protection regime when travelling, walking and camping in areas with tick or malaria carrying mosquitoes in particular. Permethrin is used to treat outer clothing, mosquito nets, ets, and DEET applied daily to exposed areas and those parts of the clothing where insect entry might occur - collars, cuffs, the waistband of trousers and along the closure at the front of the shirt.

In Spain, it seems the major risk is bedbug attack at night, not mosquitoes and other biting insects during the day. This presents a different challenge inasmuch as it really only requires nighttime protective measures to stop being bitten, together with measures to ensure that one isn't carrying the problem from place to place. This tends to drive the discussion here to the treatment of sleeping bags, liners and packs, and the use of barriers like permethrin treated sheets as prophylactic measures, and post-infestation treatment of personal items and albergue beds.

 

[MaidinBham]

I offer several points related to this research paper, and other bed bug issues:
No "in field" studies are done that use a human subject, so it is hard to translate a petri dish to actual flesh and blood.
Two or three different concentrations of DEET are used, yet only one concentration of permethrin 0.5%, which is the concentration of Sawyer DIY spray and Insect Sheild pre-treated clothing. Higher concentrations of permethrin are used in different applications such as 5% permethrin cream for scabies.
I am not aware that DEET, or for that matter permethrin 0.5% specifically states in product labels that either is effective against bed bugs.
In the cast of DEET, I do not believe that it is recommended that it be left on skin, or used up to 8 hours when you are sleeping.
Deet can not be used on synthetics (except nylon?) so that would preclude its use on many fabrics.
DEET is a repellent, it does not kill bed bugs. Places where infestations occur such as albergues, would still need bed bug control.
The researchers use three different lab colonies of bed bugs, but do not state whether these bed bugs had permethrin resistance or not. So, it may be possible that their results were skewed by the fact that the bed bugs used were already resistant to permethrin.

Is is all rather off-putting, and me thinks I need something else in my arsenal, such as a insecticide, or repellent placed under the bed posts?

Janice

 

[Stewart Allen]

DEET is generally regarded as safe for skin contact, indeed that is its main design intention (it is used to mask human sweat), see the link provided by dougfitz. All your other points are valid.

A repellent placed under the bed posts won't do much for bugs already present in the mattress...

 

[MaidinBham]

DEET is generally regarded as safe for skin contact, indeed that is its main design intention (it is used to mask human sweat), see the link provided by dougfitz. All your other points are valid.

A repellent placed under the bed posts won't do much for bugs already present in the mattress...

I didn't mean to suggest that DEET is not safe on skin - just pointing out that product label states it is for outdoor use, and when indoors you wash it off.
The linked-to EPA article does not once refer to bed bugs and DEET in the same breath - so not sure how this relates to issue. I am not sure if even the DEET product label lists bed bugs as insects that are repelled by DEET.
There are lot of scientific studies for DEET - mostly I think done with mosquitoes, but even they can not with absolute certainty state why DEET repels mosquitoes. DEET may work because it mask sweat (lactic acid) - but that is not a absolute scientific fact, especially when research shows that even in the absence of lactic acid, DEET has repellent properties. It may mask exhaled CO2, or some other human chemical that is present on the skin or exhaled. But in the end these are hypothetical only - could be as simple as the insects are repelled by the odor of DEET.
I imagine if a place were badly infested, you would have bed bugs living in mattresses, but I dont think this is the case for albergues on the Camino - you may see tell-tale signs on mattress, but they generally dont live there, are nocturnal and only come out at night - and then climb up the bed posts!

Janice

 

[C clearly]

Thanks for the informed discussion of one of the few relevant studies!

 

[Stewart Allen]

Maidinbham - The linked to EPA article that was cited is relevant in the context of the point that was being discussed - safety of DEET in relation to skin and clothing.

 

[Deleted member 3000]

experiments testing the effectiveness of different commercially available repellents against the common bed bug

It is rare for anyone to assert that permethrin is a repellant, though it has been tested as such. It is an insecticide. DEET is a repellant, not an insecticide. Comparing the two is comparing apples to oranges.

 

[Stewart Allen]

What exactly is your point here? The fact that I used the term 'repellent' as a casual descriptor, or are you challenging the basis of the article? If it's the latter, comparing two commercially available 'chemicals' (does that meet your approval?) to test their effectiveness against the bed bug seems wholly appropriate to me. If it's the former, then that's just nit-picking (which seems quite ubiquitous on this site - everyone's an expert).

 

[C clearly]

It is rare for anyone to assert that permethrin is a repellent, though it has been tested as such. It is an insecticide. DEET is a repellent, not an insecticide. Comparing the two is comparing apples to oranges.

People on this forum continually refer to permethrin as if it were a repellent, and they do not seem to understand the difference between repellant and insecticide. Repellant is what I want on my sheet. I don't need an insecticide as heat or cold will kill any I bring home in my belongings.

 

[Deleted member 3000]

Permethrin is a repellant for many insects, and is commonly used and safe. Whether it repels bed bugs or just kills them is not certain. It is certain that DEET melts many types of plastic, and is not recommended for children. DEET won't kill the bed bugs inside your pack, but permethrin will.


Entomology and Pest Management
Permethrin Factory-Treated Army Combat Uniforms (ACU Permethrin)

In order to provide Soldiers with the best possible protection from disease-carrying insects, the Army has introduced a permethrin factory-treated Army Combat Uniform (coats/trousers) known as the ACU Permethrin. Effective October 2012, the ACU Permethrin replaced the non-permethrin ACU in Military Clothing Sales Stores (MCSS). In February 2013, the ACU Permethrin replaced the non-permethrin ACU as an Army Clothing Bag Item. ACUs purchased at MCSS prior to 1 October 2012 will not be returned/exchanged for the ACU Permethrin. In May 2013, the ACU Permethrin was made available to Army National Guard/Army Reserve Enlisted Soldiers, and the Senior/Junior Reserve Officers Training Corps. There is no wear-out-date for the non-permethrin ACU. ​

​

With the introduction of the ACU Permethrin, the Army is providing a product that will enhance Force Health Protection and Readiness. A single factory treatment with permethrin offers significant benefits to the ACU Permethrin wearer including increased protection against the bites of mosquitoes, flies, midges, ticks, and chiggers for the life of the uniform. The ACU Permethrin protects Soldiers from insect-and tick-borne diseases (such as malaria and West Nile virus carried by mosquitoes and Lyme disease carried by ticks), while in garrison, training, and non-combat deployed environments worldwide. Wearing permethrin-treated uniforms is a key component of the DoD Insect Repellent System. Soldiers wearing an ACU Permethrin should continue to properly protect themselves against insect bites and diseases by wearing the uniform with the sleeves rolled down, closing all openings in clothing that might let in insects, tucking pants into boots and undershirt into pants, and keeping the uniform loose. For over 20 years, the DoD Insect Repellent System has been proven to be highly effective in preventing biting insects from becoming an annoyance or making Soldiers sick.


SAFE

• There are no known adverse health risks associated with wearing the ACU Permethrin.
• Safety testing of permethrin has been conducted almost continuously since the 1970's, following its Environmental Protection Agency (EPA) registration for use with a variety of applications including food/feed crops, livestock, Public Health mosquito abatement programs, pets, and clothing.
• After thorough research proving the safety of permethrin, the EPA registered it as an insect repellant for use on clothing, and the US Food and Drug Administration approved it for medical treatments of head lice and scabies.
• In 2009, the EPA completed the human health and environmental risk assessments for permethrin. The EPA's review reassessed the potential adverse health effects resulting from wearing permethrin-treated uniforms. Based upon the best science and studies performed to date, the EPA has determined that wearing or coming in contact with permethrin-treated uniforms is unlikely to cause adverse health effects.

EFFECTIVE

• Army personnel performing daily activities or participating in training and field operations inside the United States and overseas are at risk for insect-borne diseases, some of which may cause long-term health effects or even death. Uniforms treated with permethrin reduce this risk.
• Many vector-borne risks exist for service members who do not wear treated uniforms both here in the US and while overseas. While service members may not always be in a high-risk environment for vector-borne illness or death, having our military members protected prior to entering these environments is critical to mission effectiveness and readiness and is the right thing to do to safeguard the health of Soldiers from these risks. The risk of mosquito- or tick-borne disease is present in nearly every state.
• Permethrin repels many species of crawling and flying insects, including mosquitoes, ticks, chiggers, and flies.
• Permethrin works as a contact insect repellent.
• Ticks crawling across the ACU Permethrin will drop off before they are able to attach and feed.
• Mosquitoes and flies that land on the ACU Permethrin will quickly fall from the fabric and often die from the exposure to the permethrin treatment.
• Soldiers spend a significant amount of time outdoors, working and training in habitats where they are more likely to be bitten by both disease-bearing and annoying insects. The Army objective is to provide 90% bite protection for at least 50 launderings; an objective easily met through factory treatment of the ACU Permethrin which demonstrates 99-100% bite protection up to 50 launderings (the expected lifetime of the uniform).

[Anniesantiago]

I will continue to use and to suggest the use of permethrin as a repellant for the pilgrims I take on the Camino because in my experience, it works.

 

[Yorbas_45]

Quite informative post on pest control and hope this will also help me in getting information on how to treat bed bug bites. Planning to hire one of best pest management companies and hope to get permanent solution for this problem.

 

[nbyrne611]

I will continue to use and to suggest the use of permethrin as a repellant for the pilgrims I take on the Camino because in my experience, it works.

I called a local exterminator and spoke with their bed bug specialist. He said that permethrin (in concentrations which we can buy as consumers) does no repel bed bugs but kills them "on contact", but does not harm the eggs. So the adult bed bug has to come in contact with the permethrin. And contrary to other posts I've read on here, there is absolutely no residual effect in the over the counter spray. According to the expert, even their industrial sprays only have a residual effect of up to about 3 weeks.

He recommended that I place all electronics in a ziplock plastic bag while in the auberges, to deter them from laying eggs inside, and likes the idea of placing any clothes not on my body in a sealed bag (such as a water proof sea to summit bag that I'm bringing for this purpose). To be honest, I find it more efficient to put ALL of my items in several separate compartments when I backpack anyway, so it's just a matter of trading the "ditty" bags for maybe a couple of gallon sized ziploc bags.

He also recommends the pretreated (at the factory) bed bug under sheet (such as the lifesystems one I intend to lay down under my sleeping bag), as well as treating my pack inside and out with DEET. According to him, this is the ONLY effective repellent. In addition to this undersheet, I'm lining my sleeping bag with a preheated coolmax liner. The little extra weight is worth it imho. Permethrin is not a repellent, and he said don't even waste your time , money or confidence in anything "all natural".

In addition to these precautions, he recommends throwing anything disposable away before we board the plane for home, (including clothes we're willing to part with) and ask the person picking us up at the airport to bring a large plastic bag to seal our remaining items in (including pack) so that we can throw them directly into washer and dryer (freezer for electronics) when we arrive home.

After talking with him, I understand more and although I know I can't do anything about the presence of bed bugs, I feel more confident that I won't carry them along the walk or into my home.

 

[trecile]

He also recommends the pretreated (at the factory) bed bug under sheet (such as the lifesystems one I intend to lay down under my sleeping bag), as well as treating my pack inside and out with DEET. According to him, this is the ONLY effective repellent. In addition to this undersheet, I'm lining my sleeping bag with a preheated coolmax liner. The little extra weight is worth it imho. Permethrin is not a repellent

Better test the DEET on your backpack before spraying the entire thing since DEET can destroy some synthetic fabrics. And you realize that the pretreated undersheet and liner are treated with permetherin? Why not use that on your backpack too?
Also, what some people do is carry a large plastic garbage bag, and put their backpack in it each night, making sure yo secure the top.

 

[jmcarp]

Better test the DEET on your backpack before spraying the entire thing since DEET can destroy some synthetic fabrics.

I left a container of DEET insect repellent in the storage pocket in the door of my car; it leaked and ate a hole in the bottom of the plastic pocket. Based on that experience, I'm sure it would do the same or worse on any of the popular synthetic fabrics used for backpacks.

 

[HighlandsHiker]

Better test the DEET on your backpack before spraying the entire thing since DEET can destroy some synthetic fabrics. And you realize that the pretreated undersheet and liner are treated with permetherin? Why not use that on your backpack too?
Also, what some people do is carry a large plastic garbage bag, and put their backpack in it each night, making sure yo secure the top.

With regard to the large plastic garbage bag, I do something like this too - I take a white plastic kitchen bag and line the whole upper cavity of my pack with it so that there's extra rain protection, extra bug protection, so things slide around in there easily against the plastic, and so it's easy to see items in lower light conditions against the white plastic while rooting in the bag.

 

[dougfitz]

Based on that experience, I'm sure it would do the same or worse on any of the popular synthetic fabrics used for backpacks.

This is not my experience, having had DEET leak in my pack when I hadn't taken much care replacing the cap on a tube of a high DEET concentration repellent. The pack fabric and zipper were covered with DEET, both without any obvious ill effect. However, the waterproofing cover over the outside surface of the zipper was completely destroyed. My recollection is that the fabric is a nylon cordura variant. Given the widespread use of nylon cordura as a pack fabric, I suspect that DEET won't do much, if any, damage to most packs. Waterproof zippers, on the other hand, might be more vulnerable.

 

[jmcarp]

This is not my experience, having had DEET leak in my pack when I hadn't taken much care replacing the cap on a tube of a high DEET concentration repellent. The pack fabric and zipper were covered with DEET, both without any obvious ill effect. However, the waterproofing cover over the outside surface of the zipper was completely destroyed. My recollection is that the fabric is a nylon cordura variant. Given the widespread use of nylon cordura as a pack fabric, I suspect that DEET won't do much, if any, damage to most packs. Waterproof zippers, on the other hand, might be more vulnerable.

That's good to know. I'd still recommend testing DEET exposure on a small area of a pack just to be sure it does not cause damage.