Researchers at the University of Kentucky discuss treatment options for bed bugs when insecticides may not be desirable.
Bed bugs are well-adapted to living with humans. Like other successful parasites, they prefer to live near their next meal. In the case of the nocturnal bed bug, this usually means close to where people sleep or lounge. In recent surveys of bed bug-infested apartments, for example, more than 90 percent of the insects were found living in beds, sofas and recliners (see "Battling Bed Bugs in Apartments," PCT August 2006). Ironically, these are the places many firms are uncomfortable spraying due to client concerns about pesticides. This article examines non-chemical options for battling bed bugs when pesticides may not be an option.
DISPOSAL. The fastest way to reduce bed bug numbers is to throw out infested items. Bed bugs can be hard to eradicate from beds and upholstered furniture because so many may be present and well concealed. Box springs, sofas and recliners are especially challenging, affording unlimited hidden harborage within inches of the host. Heavily infested or damaged mattresses, frames and headboards also may warrant disposal. Nonetheless, throwing out infested items isn’t an option for some customers and often may not be necessary. One misdirected homeowner we know threw out $50,000 worth of furniture following advice posted on the Internet. Another discarded almost everything they owned including their entire wardrobe, kitchen utensils, children’s toys and an infant potty seat. Knowledgeable pest managers are better able to advise clients on what can stay and what should go. When infested items are discarded, bagging or wrapping them prevents dislodgement of bugs en route to the Dumpster.
ENCASEMENT. One good way to limit bed bug habitation of beds is encasement. Encasing both the mattress and box spring denies them access to inner, hard-to-treat areas. Once the cover is installed, any bed bugs which happen to be inside are entombed and eventually will die. A tight-fitting smooth outer cover also makes it easier to spot and destroy any bugs reappearing on subsequent visits. Encasement makes a lot of sense if the old infested bed is to be kept. They also help protect new bed components until the current infestation is eliminated. Some pest control firms supply and install the bed covers themselves to ensure that they will be used and installed properly.
Zippered bed encasements of various qualities are available at bedding supply stores. Bed bugs trapped inside will not bite through the fabric, but cheaper covers are more likely to tear during installation and use. One high quality encasement developed specifically for bed bugs was recently introduced by Protect-A-Bed (Chicago) and Cooper Pest Solutions (Lawrenceville, N.J.). The product is available through the pest control distributor Residex. No encasement product, however well constructed, will keep bed bugs from crawling onto a bed and biting a sleeping person.
VACUUMS. Vacuums can remove many types of pests ranging from cockroaches to ladybugs. Routine vacuuming by clients is seldom of much benefit against bed bugs because they hide in places where normal housecleaning efforts do not reach. Targeted vacuuming of infested harborages, however, can be useful if performed properly and limits of the procedure are understood.
Bed bugs are harder than cockroaches to dislodge with a vacuum. Adults and nymphs cling more tightly to surfaces and each tiny translucent egg is affixed with a cement-like substance. When vacuuming bed bugs, better results are achieved by scraping the end of the suction wand repeatedly over the harborage area. While many bed bugs will be dislodged, some individuals — and especially eggs — will be left behind. Removal becomes difficult if not impossible when bugs and eggs are located deep within crevices of wood, fabric or upholstery.
Another potential concern when vacuuming bed bugs is the chance they will be spread. Perhaps more so than with cockroaches, we have noticed some bugs and plenty of eggs surviving the high-speed ride down the vacuum hose into the collection bag. If vacuum bags are not discarded, bed bugs could be transported to other clients or back to the office. Brush attachments enhance the potential for spread by allowing bugs and eggs to adhere to the bristles.
STEAMERS. If bed bugs have a weakness, it’s elevated temperature. Temperatures of about 120°F are lethal to most insects provided they cannot escape to a cooler location. The advantage of steam is that heating is intense and immediate, killing both bugs and eggs on contact.
The types of steamers used for bed bug treatment are like those used for sanitizing floor drains. When targeting bed bugs though, the less moisture emitted the better, especially when treating mattresses and other slow-drying materials where mold growth is a possibility. Low-moisture steamers are available from such companies as AmeriVap Systems, Atlanta, Ga., 800/763-7687; and Hi-Tech Cleaning Systems, Columbus, Ohio, 866/606-1355. It is important to have a commercial-grade steamer with a water tank large enough to accommodate extended use between fill-ups. Most machines come with variable steam outputs and multiple attachments. Larger brush heads (like the triangular one pictured in the photo below right) usually work best. Small diameter tips are less efficient and frequently emit too much pressure, causing bugs and eggs to be blown off the substrate. While some of the dislodged bed bugs may die, others could survive and be scattered here and there.
When using steam, it is important that the bed bugs be exposed to lethal temperatures. Ideally the steamer head should be moved directly over the surface being treated. Holding the steam head farther away might only give the bugs a warm moist bath. A good way to confirm that lethal temperatures are being achieved is to use a digital infrared thermometer. Instantaneous temperature readings can be had by pointing the device at the area just treated. Alternatively, one can hold their hand several inches from the steam head and slowly and carefully move it closer. Vapor too hot to touch is what’s needed to kill bed bugs and eggs on contact. An effective way to further elevate the temperature of emitted vapor is to wrap the brush head of the steamer in a towel. A small tea towel works well and can be secured to the steam head using the spring-mounted clips (see photo on page 30). This technique produces vapor so hot that the steam head can now be moved quickly and efficaciously over infested and suspect areas. Using the towel method, lethal temperatures can be achieved several inches from the steam head, which can be useful when treating hard-to-reach areas (e.g., between cushions of upholstery or the framework of sofas and box springs). Towels that become overly moist can be replaced.
Steam can be used to treat almost any area where bed bugs are found or suspected. Logical places include beds, couches and recliners, baseboards and carpet edges, beneath and within nightstands and dressers and floor areas (especially under and around beds). Avoid treating finished wood surfaces or delicate items that might be damaged by high heat. Vacuums and especially steamers are useful when battling bed bugs. Neither, though, affords residual protection against bugs or eggs which may have been missed.
LAUNDERING/DRYING. Bed bugs often infest bedding, clothing and other personal belongings which cannot be treated with insecticides. An oft-mentioned way to de-bug such items is laundering — yet to our knowledge, no testing has been done to verify effectiveness. A simple experiment was conducted to study this question. Three groups of live bed bug adults, nymphs and eggs were placed in small nylon mesh pouches which were then placed inside cotton socks. The bed bug-provisioned socks (along with a full load of clothing) were then run through a standard wash cycle using hot water. A second trial was run with similarly infested socks placed only in a clothes dryer. The bed bug-laden socks were accompanied by a load of unwashed clothing and subjected to high heat (greater than 175° F) for five minutes. No bed bugs or eggs survived the washing or drying cycles, suggesting that either regimen, alone or in combination, is effective.
Clothing, footwear, area rugs, toys, stuffed animals, backpacks and other non-launderable items can conveniently be de-infested by heating them for a period of time in a dryer at most settings. For reference, a typical clothes dryer run for five minutes at low, medium or high heat produced temperatures of about 140, 150 and 180°F, respectively, amongst a bundle of dry clothing — plenty hot to kill bed bugs. While certain items may require professional dry-cleaning, utilizing conventional washers and dryers may help limit the spread of bed bugs to these establishments.
SEASONAL TEMPERATURES. Lethal outdoor temperatures have long been employed in the battle against bed bugs. In the tropics, infested bedding is often left out in the sun and such methods can also be used during warm seasons in this country. It’s risky, however, to rely on ambient heating to achieve lethal temperatures in all harborage locations. Wrapping items in plastic before placing them outdoors in a sunny location (preferably on pavement), produces higher internal temperatures. It also pays not to over pack — more trash bags with fewer items make it harder for bed bugs to find cooler places to hide. Monitoring with a thermometer is also prudent, with a target internal temperature of at least 120° F.
In colder climates, freezing might be a way to de-infest furniture and other belongings. Bed bugs and their eggs can be killed by very low temperatures, but it is difficult to achieve them without using a deep freezer. Temperatures below 0°F for one to two weeks are generally believed to be needed to reliably kill all life stages. Fluctuating winter temperatures which often extend above this level are probably less effective and are currently being studied by Dr. Steven Kells at the University of Minnesota. Overall and throughout much of the country, heating tends to be a faster, more reliable option than chilling.
STRUCTURAL HEATING. Elevating the temperature within buildings has been used to eradicate pests ranging from grain insects to termites. Structural and containerized heat treatments are also being developed for bed bugs. Companies such as TempAir (Burnsville, Minn., 888/838-4035) have begun licensing the patented technology to interested pest control firms. Portable heaters and fans are used to gradually heat the air within rooms to about 125 to 130°F while monitoring with strategically placed sensors. A licensing and royalty fee is typically required along with the initial equipment purchase.
While heat treatments hold promise, eliminating infestations by raising the temperature within a building may not be so easy. As observed with cockroaches, bed bugs may seek out cooler areas as the temperature within rooms builds. Whether some bugs will be able to survive by moving to cooler locations (including adjacent units) still needs further study.
STERIFAB/BEDLAM. Sterifab and Bedlam are often used to treat bed bug-infested beds and upholstered furniture. Although both products are technically pesticides, some companies choose to use them because of their comparatively short residual when treating human contact surfaces. Sterifab and Bedlam contain mainly alcohol and the relatively short-lived pyrethroid d-phenothrin. There is uncertainty whether either product has sufficient residual activity to kill bed bug nymphs emerging from eggs.
To study this question, groups of adult bed bugs were sprayed directly with each product. In another experiment, adults and newly emerged nymphs were confined on filter paper discs that were treated one hour, two days or seven days earlier. Three different bed bug populations were evaluated: two previously shown to be susceptible to pyrethroid insecticides, and a third population known to be resistant.
When adult bed bugs were sprayed directly with Sterifab or Bedlam, all (100 percent) died including those from the pyrethroid-resistant population. Efficacy against resistant bugs presumably was related to the alcohol present in both formulations which itself is lethal to bed bugs as a contact (wet) spray. When newly emerged nymphs were confined on surfaces treated with Sterifab or Bedlam one hour, two days, or seven days before, almost all (95% to 98%) of the pyrethroid-susceptible nymphs were killed, but nearly none (2%) succumbed from the resistant population. These preliminary findings suggest that both products provide excellent contact kill as a direct spray against adults and nymphs. Whether they’ll also afford residual protection against emerging bed bug eggs depends on the (pyrethroid) susceptibility of the population and perhaps other factors still being investigated.
CLOSING THOUGHTS. Several useful non-chemical tools are available for managing bed bugs. These tools will become even more important when battling pesticide-resistant populations. It should be noted, however, that none of these tactics afford extended residual protection against reinfestation. Any bugs or eggs managing to escape treatment will live to bite another day. So will any other bed bugs which happen to appear later on. Residual insecticides still will be needed — a conclusion also reached in the 1930s and ’40s after all manner of pesticide-free approaches were devised and tried. Barring the discovery of an incredibly effective product with a similarly permissible label, programs incorporating chemical and non-chemical tactics will probably be most effective. If necessity is the mother of invention, we should be in for an interesting ride.
All photos are courtesy of M.F. Potter
Michael F. Potter and Kenneth F. Haynes are professors at the University of Kentucky. Alvaro Romero is a Ph.D. student at the same institution. Erich Hardebeck is vice president of Permakil Pest Control, Covington, Ky.