Wednesday, March 3, 2010

Guidelines for killing bed bugs in laundry

The nice thing about an emergency pest problem, like the current bed bug epidemic, is that such problems attract a lot of attention from the research community.  A few weeks ago I reported new research from the Wang laboratory at Rutgers University on some interesting facts about bed bug infestations in high rise apartments. In the same journal two British scientists from the University of Sheffield, R. A. Naylor and C. J. Boase, report on another aspect of bed bug management...how to kill bed bugs in bedding and clothing using laundering procedures.

Knowing how to dis-infest clothing is important to pest control, because, as the authors so carefully explain, bedbugs "may seek harborage among clothing stored close to the bed, or may be entangled with bed linen while it is being changed. "  And, "once associated with clothing or linen, there is a risk that bed bugs may then escape insecticide treatments, and may be transported to new locations."

Although there have been many recommendations on the Internet and in print concerning how to dis-infest laundry, Naylor and Boase point out that such recommendations are often vague or conflicting and have been based on little formal research.  So they set out to look at the temperatures and conditions necessary to ensure 100% mortality of adult, nymph and egg stages of bed bugs.

To do this they took laboratory reared bed bugs and sealed them in cotton bags.  These bags were then placed among sheets or in the pockets of clothing to assess mortality of standard cleaning methods.   The results were enlightening and should help in recommendations for how your customers can ensure maximum effectiveness of methods to disinfest household articles.

A summary of the results of this study include the following:
  • Freezing can kill bed bugs.  Reducing temperatures to -17 degrees C (0 degrees F) for 2 hours will kill all bed bug life stages (about the temperature of a chest freezer, not a refrigerator freezer).  A 5.5 lb batch of clothes, however, does not drop to 0 degrees F immediately.  The researchers found that it took about 8 hours for the temperature in the center of that wad of clothes to killing temperature.  Upshot?  Put clothes in freezer for at least 10-12 hours.
  • Bed bugs are also susceptible to high temperatures of 40-50 degrees C (104-122 degrees F).  In order to reach these temperatures, clothing to be dis-infested can be placed in a large tumble drier at the HOT setting for at least 30 minutes (for a 7.7 lb load).  A 10 minute HOT tumble dry only killed about 75% of nymphal bed bugs, 85% of adults.  Interestingly, the COOL cycle killed almost no bed bugs.
  • Soaking clothes in cold water for 24 hours (without detergent) killed all adults and nymphs, but killed no eggs. Unfortunately, the researchers did not test whether soaking clothes in cold soapy water for 24 hours would kill eggs.  This alternative treatment might be useful, especially for cleaning clothes that are labeled for cool wash and dry only.
  • Dry cleaning killed all life stages of bed bugs, and would be an appropriate treatment for delicate and temperature sensitive fabrics.
  • When washing clothes, wash water at 60 degrees C (140 degrees F) on 30 minute wash cycles killed 100% of all life stages.  Washing at 40 degrees C (100 degrees F) killed all adults and nymphs, but only 25% of eggs.  So clearly, washing clothes for bed bug dis-infestation should be done at the hottest temperatures (about 140 degrees F).
Experience with many pests verifies the wisdom of using multiple control tactics to control pests--a basic tenet of IPM.  Certainly bed bugs are no exception.  Reducing clutter, systematic inspection and treatment of the bedroom and other infested rooms, trapping and ongoing monitoring, and effective treatment of all exposed household articles, including clothing, are all essential components of good bed bug control.  This research should help all of us with fabric dis-infestation.

14 comments:

keith said...

Thanks Mike for this useful information, I always have customers asking how to kill bedbugs. One thing I will add - make sure you take care in moving things around. If you take clothes out of the infested room, put in a bag first then transport. You don't want to move them to another room.

Bed Bugs Northwest said...

Thanks for this article. There is so much misinformation about laundry and bed bugs. When we had an infestation in our building, I saw a bed bug climb out from the front of lint trap in the dryer in our common laundry. I can only assume someone put dry bedding in the dryer and bed bugs (or at least one) shook off and was able to avoid the heat of the dryer. At least that bed bugs life was cut short. So, please don't put dry infested laundry in the dryer to kill bed bugs. Always wash first to drown them, and they dry, and dry a long time.

bed bug extermination said...

Washing, drying and storing clothing properly can make a difference to bed bug treatment, but make sure you're doing it right.

Adeel Akram said...

Hi Guys,

Just wondering what your take on this would be..I have moved into a rented accommodation in a house and have had bed bug bites and have seen bed bugs around the room. My landlord has sprayed the 'Zero' bed bug spray available from ebay. Although he has done this I am now sleeping on the couch and have decided to move to another apartment.

As a precaution I will be washing all my clothes and maybe putting my laptop and other bags in the drier too as well as throwing away all my bed sheets, pillows and duvet. Will then place the washed clothes in black bin liners and store them away from the room.

Would it help to soak all my clothes first in the bath with some Dettol (which is an anti-septic) and then run them through a hot wash and hot dry? what other precautions should I take?

Thanks again.

Adeel

Mike Merchant, PhD said...

Adeel's comment brings up a couple of good points. One, in many states (Texas is one of them) landlords are not legally allowed to apply pesticides to their apartments without a license. His question points out the wisdom of this restriction. Landlords generally don't know what to do to control pests and may use insecticides improperly. Two, by moving out of the improperly treated room Adeel has spread the bed bugs to other parts of his apartment. Adeel needs professional pest control, not a laundry disinfectant.

Adeel said...

Thanks for your comment Mike, although I'm not quite sure on how to take it..

Although the room has bed bugs I have ensured that the only thing I take from the room is washed before use. I have had a lot of sleepless nights and much discomfort therefore have moved onto the couch (with new duvet and sheets) now the only high probability of bed bugs spreading to the couch is if they clung onto me, which frankly scares me even more.

Mike Merchant, PhD said...

Adeel, try emailing me directly through the "about me" link and we can discuss.

Anonymous said...

I recently went on travel for work. I checked into the hotel, then changed my clothes quickly and went to meet my coworkers for dinner, leaving my open suitcase on the bathroom floor. I got back from dinner an did my standard "bedbug check" by pulling back the fitted sheets. there were some brown spots and a small shedded exoskeleton in the crease of the mattress. I changed hotels. Now I've returned home. I've left the suitcase in the car for 2 days in about 30 degrees F (during which time we've only driven for 15 mins or less at a time). Is it safe to bring in my suitcase? I've already emptied it of some of the laundry, putting it directly in the wash, but I don't know how to ensure the suitcase itself is ok. Thanks...!

Anonymous said...

I buy self sealing laundry bags which dissolve in the washer to help prevent possible infestation of bed bugs from hotels. Before we go on vacation, we leave spare clean clothes in the garage. Once home we empty our suitcases into the laundry bags, seal them, change into clean clothes and bag and seal our clothes we were wearing on the plane. We wash the bags on a high temperature andleave each bag in the garage until it's time to launder. And we always check the hotel for bedbug infestation. No problems so far.

Anonymous said...

Will DE powder,pest extermator.traps,zip up bed covers and heating the whole place ,get rid of the bed bugs?

Mike Merchant, PhD said...

There is no magic formula for getting rid of bed bugs that will work in every setting. That's why professional assistance is always desirable. All the things you mention (DE, bed covers, various types of heat treatments) are good pieces to a bed bug control program, but none are a guarantee of control.

Anonymous said...

Hi,
I was wondering if washing all my clothes at 60C is enough to kill all bed bugs and eggs?
Or do I have to dry all my clothes as well?
Or can I just air dry them, and are they then safe enough to put them away?

Thanks for the help :)

Mike Merchant, PhD said...
This comment has been removed by the author.
Mike Merchant, PhD said...

Good question. Yes, drying alone is sufficient to kill all bed bug life stages, as long as you follow the guidelines above for heat and drying times. Skipping the wash allows you to treat clothing items that are not designed for normal washing, like silks or woolens. If you don't have a drier, then washing in hot water alone will also kill bed bugs. The tests were done with soap, which may contribute to bed bug mortality; but the research did not look at whether detergent alone would kill bed bugs.