Steam is used selectively by many pest control companies to kill bedbugs.
Steam treatment combined with insecticide treatment can provide better long-term control than insecticides alone.
Properly applied, steam will kill all stages of bedbugs.
The use of steam to control bedbugs on mattresses, box springs and upholstered furniture is especially attractive to many suffering from bedbugs because it reduces the reliance on insecticides.
People also feel that the treatment is "disinfecting" their beds, although this may not be accurate.
As with other physical methods, of course, steam provides no residual activity, and other actions are necessary to control the bedbugs hiding in "unsteamable" areas.
There are many brands and types of steam machines available, but not all are suitable for bedbug control.
Quality machines come with large tanks for extended operation, variable steam output and a selection of attachments and brushes.
Choose steam-generating machines that can produce low vapor rates.
The steam produced by these machines is sometimes called "dry steam" because there is less water content than the steam from machines with high vapor rates.
Dry steam units reduce the risk of water damage and mold growth from the steaming process.
As a rule, when steaming for bedbug control, the less moisture the better, especially when treating slow-drying materials.
Expert opinion varies on the issue of steam pressure.
Some advocate higher working pressures of 50 pounds of pressure per square inch (PSI) or more to provide better penetration and shorter exposure times.
Others recommend that you avoid high steam pressure because it can blow bedbugs off of the treated surface without killing them, scattering them into untreated areas.
Accessories And Steam Heads
The best steam heads for bedbug control are those that produce reduced flow rates over a wide area.
There are different types of applicator tips, nozzles and brushes, and not all are suitable for bedbug work.
Single, narrow tips produce high pressure and tend to blow the bugs away rather than kill them.
Use a multiple-jet steam head, a wide steam applicator or a wide brush head.
Larger heads cover more area on a single pass and are less likely to blow the bugs away.
There is a very narrow zone of effective steam around the steamer head, particularly those steamers that are operated at low pressures.
Steam that is hot enough to kill bedbugs is too hot to touch.
Operators need to place the head in direct contact with the surface being treated.
The head must move slowly across the treatment area to be effective, something in the neighborhood of one foot every 10 to 15 seconds.
The only way to increase the speed of treatment is to increase the effective temperature in the target area.
Doing so, however, increases the risk of heat damage.
Some experts recommend wrapping the steamer head in a small towel.
According to proponents of this method, the increased heat generated by the towel-wrapped head permits the operator to move the head more quickly along the treatment surface while still killing the bedbugs and eggs.
Whether or not the steam machine operator should use a brush-equipped steamer head is subject to debate.
Some say no because the bristles can fling eggs and bugs away from the treatment zone; others say yes because the brush opens up the nap or seam of the fabric and cleans out cracks and crevices to improve kill, while mechanically killing the bugs as well.
Steam treatment will kill bedbugs in any site that the steam can reach.
The two main limitations are the potential heat or moisture damage to treated items and the labor and time it takes to apply the steam effectively.
Precautions When Using Steamers
Steam machines differ from one to another.
Operators should carefully read the instructions to ensure peak efficiency and safety.
Electric shock is a safety issue, as steam contains enough water to conduct electricity as it condenses.
Do not steam electrical outlets, switches and other electrical devices without first shutting off the electricity.
Certain materials may be damaged or colors faded by the heat and moisture generated during steam treatment.
First steam an inconspicuous area of the following items or materials:
- Upholstered couches and chairs, textiles and anything made of leather, acrylic, velvet or linen
- Painted or finished surfaces and waxed furniture
- Glossy plastic, which may be dulled by steam
- Wallpaper and other glued wall coverings.
Be sure that steamed materials are completely dried.
Larry Pinto and Sandy Kraft are entomologists at Pinto & Associates Inc. and have consulted on urban pest problems for over 25 years. Between them, they have written dozens of books and manuals and hundreds of articles about pest control and have published Techletter for pest control technicians since 1985. They can be reached at Pinto_Associates@Comcast.net or through links at www.Techletter.com. Richard Cooper is an entomologist, the technical director of Cooper Pest Solutions of New Jersey and one of the pest control industry''s leading experts on bedbugs. He gives numerous talks on bedbugs around the country, has authored chapters in the Mallis Handbook of Pest Control and was awarded the Pest Control Technology Leadership Award.