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Bedbug Biology and Control

The common bed bug (Cimex lectularius) is the main species that is currently found infesting buildings and homes throughout the United States. There are a number of other species of bedbugs found around the world. These are more frequently associated with birds and bats and have been found on occasion in homes when these animals have been nesting on/within a structure. The tropical bedbug, Cimex hemipterus occurs throughout tropical areas of the world thus prefers higher temperatures and humidity than Cimex lectularius. In Europe and the United States, well-established infestations of this species are quite rare; in the Western Hemisphere, it is seldom found north of Puerto Rico and Mexico, or south of Brazil and Peru. Occasional limited populations have been found in Chile and Florida. Other species of bedbugs, including swallow bugs, bat bugs, and other bird-feeding bugs occur in various temperate parts of the world. On occasion they may bite humans and are found sporadically in or around homes and other structures.

Cimex hemipterus occurs primarily in more tropical areas but has been found in temperate areas of the U.S. This is especially so when people have engaged in international travel. Bedbugs have been known by a variety of names including mahogany flat, wall louse, crimson rambler, chinch, heavy dragoon and redcoat.

Bedbug with piercing sucking mouthparts inserted into host (human) sucking blood. Courtesy of Center for Disease Control (CDC).

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Piercing sucking mouthparts of bedbug. Courtesy of Center for Disease Control (CDC).

Adult are reddish-brown, flattened critters that are about 3/16 inches long and up 1/8 inches wide. After feeding on blood, bedbugs increase considerably in size and are swollen and dull red in color. Their eyes are deeply pigmented and the sides of the flattened collar-like pronotum curves somewhat around the head. The immatures (nymphs) vary considerably in size and are basically colorless (unless recently fed) with the first instar nymphs about the size of a period in this article. Bedbug eggs are white, oval in shape and about 1 mm long (very difficult to see with the naked eye). Adult tropical beg bugs are approximately 1/4 inches larger than the common bedbug.

It is thought that bedbugs were originally ectoparasite of bats living in caves but subsequently changed hosts to include humans (cavemen) occupying in the same habitat. These pests are mentioned in medieval European texts and in classical Greek writings back to the time of Aristotle. It is believed that these bugs were originally imported into the U. S. by early Europeans. There are colonial records of the early 18th century where passengers were prohibited from bringing bedding material on ships. During the early 1900s, bedbug infestations were quite common in American homes.  At that time, they were rated amongst the top structural pests with an estimated 1/3 of all residences infested at some point in time.  However, with the discovery and use Dichlorodiphenyltrichloroethane (DDT) and other insecticides in and around homes, these pests quickly disappeared.  The effectiveness of these chemicals was mainly due to their long residual activity. As invariably occurs, with the overuse of pesticides, bedbugs developed resistance to DDT after a few years, but other chlorinated hydrocarbons (such DDT and lindane) and organophosphates (malathion) were used to keep these pests at a low level. Again the main factor why these chemicals were more effective in controlling bedbugs than modern chemicals is persistence.  For example, DDT when sprayed on a bed remains active for up to 1 year. On a wall, this chemical can remains active even longer. With this residual activity, a bed bug that came to feed on a sleeping person was eliminated, and since they all need to feed at one time or another, the infestation was eventually eliminated. 

In many undeveloped countries, bedbugs remained and still remain important pests. In the past 10 to 15 years, bedbugs have made a huge comeback in many areas of the world including all 50 states as well as Puerto Rico, Guam, American Samoa, Australia, Canada, parts of Europe and Africa.

In the U. S., many of major cities are presently experiencing considerable bedbug infestations. These include Los Angeles, San Diego, San Francisco and New York. Some cases have escalated to extreme levels resulting residents to label the infestations "house herpes".  In California, one of the large companies that utilize bedbug dogs to detect infestations reported that they had a mere 12 searches 10 years ago. A couple of years later, the same company reported 33,000 searches. The National Pest Management Association recorded a 71% increase in bedbug calls between 2000 and 2005. Twenty five percent of the North Carolina 700 plus hotels surveyed between 2002 and 2006 required bedbug treatment. These statistics remain similar today.

Reasons for Increased Infestation. There are several possibilities for why this major increase has occurred. One possible reason is a tremendous increase in worldwide travel. Today people commonly travel to and from all parts of the world. This includes many countries and areas where bedbugs are common. Also included are leisure and business travelers who commonly move between continents. In addition, countries are increasingly multicultural with residents traveling back and forth from their homelands. Of course, bedbugs are great hitchhikers and easily travel in luggage, cars, busses, cruise ships, airplanes and trains.

Another possible reason is the significant increase in illegal aliens and other temporary workers coming in from Mexico and Central America (countries where bedbug populations have remained fairly static. They (especially temporary workers) commonly shift in and out of group residences and in low-income apartments.  It is fairly common for these individuals to readily change or leave residences for new jobs or for them to return to their home country. These conditions can quickly lead to importation and movement of bedbugs.

Thrift shops, secondhand stores, swap meets, antique stores, flea markets, and Goodwill stores are on an increase in the U.S. This is especially true with the present economic crisis. Any used item is a possible source of a new infestation. Very frequently residents will throw out furniture in attempts to rid their home or apartment of these pests. A nice sofa, chair or even new looking bed is far too attractive to some to let the trash man carry these away.

There apparently are geographic hot spots of these pests. Reportedly, there were at one point 3 apparent U.S. epicenters at poultry facilities in Texas, Arkansas, and Delaware. In these cases, workers in these farms were spreading bedbugs and unknowingly transporting them from the facilities to their residences and elsewhere.

Also changes in pest control techniques and the development of resistance to commonly used pesticides (pyrethroids) has certainly added to the reestablishment of the pests in the U.S. In the past, cockroaches were controlled by crack and crevice treatment in homes, hotel rooms, low income housing and other indoor locations. As a result, bedbugs were simultaneously controlled with these pesticides. However, during the mid-1990 there were major changes in these practices. Treatments of baseboards in motels, hotels, apartments and homes were replaced with the use of baits for ants and cockroaches. Obviously bedbugs don't feed on baits as they are blood suckers. In this absence, bedbugs were able to travel safely from the luggage or other locations--hence the beginning of the problem. It is of importance to note that once the bedbug problem developed, there were few effective pesticides available that had the residual activity needed to control these pests. Many professionals point out the dramatic rise in activity of this pest occurred approximately 10 years after applicators stopped spraying for cockroaches.

Biology. Since the common bedbug in the U.S. feeds on human blood at night (between midnight and 5:00 am), it follows that they most commonly occur around or on beds as this is where the food is, namely us. Bedbugs are attracted to CO2 produced by the victim's breath and body heat.  However, they are only able to detect these host cues over short distances. This distance is about 3 feet away for CO2 and even less for heat. It is not well understood how they are capable of finding a person in a bed when initially located in a closet or other distant locations. Even though they have a very flat body (definitely not streamline) and relatively short legs, they are able to move relatively quickly, and it is thought that they randomly wander in search of food. In most cases, the majority of an infestation is found on the bed. However, this is not always the case in heavy infestations. In such cases, many ultimately seek refuge at distances several yards from the host

Bedbugs exhibit gradual metamorphosis. That is they pass through 3 stages during the life cycle, namely egg, nymph and adult. The nymphs are very similar in appearance to the adults except they are smaller but gradually increase in size with progressive molts. There are 5 nymphal instars or sizes.

The eggs of these insects are tiny, whitish, and somewhat difficult to detect on most surfaces (individual eggs are about the size of a speck of dust or period on this page). When first deposited they are sticky and readily adhere to surfaces thus making them difficult to remove. Under favorable conditions, each female lays 100 to 500 eggs at a rate of between 1- 7 per day for about 10 days.  She will then have to feed again to produce more eggs and is capable of producing between 5 and 20 eggs from a single blood meal. Maximum egg deposition occurs when the temperature is above 70°F (21°C) and typically ceases when temperatures drop below 50°F (10°C). Eggs and their shells are found singly or in clusters and in or near crevices where bedbugs hide. At temperatures above 21°C (70°F), eggs hatch in about 10 days. At lower temperatures hatching may take as long as 28 days.

Under ideal conditions, the survival rate of bedbug eggs is approximately 97%.  Even under optimum conditions, some nymphs will die prior to reaching the adult stage. This is especially true with the first instars. They are particularly vulnerable due to their small size and relatively large surface area. Newly hatched nymphs are exceptionally tiny and cannot travel great distances to locate a host. If an egg is laid too far from a host, the first instars nymph may die of dehydration before ever taking its first blood meal. However, laboratory studies have found that overall bedbug survivorship is good under favorable conditions, and  more than 80 % of all eggs survive to become reproductive. Due to the large number of eggs a female can produce under optimal conditions (temperatures >70° F but < 90° F in the host), a bedbug population can double every 16 days.

Without a source of food, bedbugs can enter a dormant condition and reportedly can live for 18 months while well-fed specimens typically live 6 to 9 months. However, a recent laboratory study has shown that starvation has a negative impact on bedbug survival. This modern study contradicts European studies conducted in the 1930s and 40s when it was determined that starved bedbugs could survive periods lasting more than 1 year. This may have been true for individual bedbugs in the UK living at very low temperatures (< 40° F; because of no central heating); modern bedbugs collected from homes in the United States do not live that long. On average starved bedbugs (at any life stage) held at room temperature will die within 70 days. Most likely these bedbugs are dying of dehydration rather than starving to death. Bedbugs have no source of hydration other than their blood meal. 

The unfed first instar nymph is almost translucent in color, but subsequent nymphs progressively darken in coloration. Recently fed nymphs are blood red in coloration. Bedbugs are cold blooded, like all insects. This means they take on the temperature of their surrounding environment. Correspondingly, the cooler the surrounding environment, the longer it takes them to complete their development.  

Bedbugs will travel 5 to 20 feet from an established harborage to feed on a host. Nymphs and adults are gregarious (found together in groups). This grouping or “nesting” behavior is a result of 2distinct pheromones: an airborne aggregation pheromone that attracts the bedbugs to the location, and an arresting pheromone that causes them to settle. Although they normally venture out to feed in the early morning hours, they occasionally feed at other times if given the opportunity. Typically, only when bedbugs are starved will they feed during daylight hours. However, there are many well-documented cases of bedbugs feeding during daylight hours. In some cases, they have become established in movie theaters (especially older theaters with leather seats). Apparently, during the day they come out of the seats to feed when the lights are turned off. They can gain access to their host by crawling up the legs of a bed or they have even been observed crawling across and dropping from the ceiling to float down to their host.

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Aggregation of bedbugs.  Image courtesy w.en. User Rogesoss

Mating. The mating behavior of bedbugs is at times quite competitive and strange. Males inject their sperm into the female by puncturing (penetrating) the body wall as the female lacks a natural opening for reception of his sperm. The sperm then swim throughout the female’s body cavity eventually finding and fertilizing her eggs. Apparently, this is not limited to females. Occasionally, males are found with copulation scars where other males have penetrated their body wall. This probably happens when a male penetrates another male that is copulating with a female and subsequently injects his sperm into the mounted male. In this case, some of his sperm finds its way into the sperm ducts of the mounted male, which in turn is injected into the female upon ejaculation.  

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Bedbugs in traumatic insemination. Image courtesy of Richarde Ignell, Sweedish University of Agricultural Sciences (Wikimedia Commons)

Bites: Symptoms and Treatment. Since bedbugs are so secretive, one of the first signs of their presence (especially in an initial small infestation) frequently comes by their feeding on the occupants. The bug pierces the skin with 2 hollow feeding tubes. One of the tubes injects saliva that contains anticoagulants and anesthetics, and the other tube withdraws the blood of the host. The anticoagulant serves to prevent blood from coagulating in the tiny tube-like mouthparts, and the anesthetic serves to numb the area and prevent detection of their presence. These injected chemicals are protein based and the body reacts to their presence by producing antibodies. This frequently results in an antigen-antibody reaction, meaning that your system has become allergic to the chemicals.

The first indication of a bedbug bite usually occurs from the desire to scratch the bite area and may take minutes, hours or even weeks to occur. It is not unusual to have been bitten many times before symptoms occur. For this reason plus their secretive behavior, an initial infestation may not be detected for some time. One estimate is that it will frequently take 3 months for an initial infestation to develop to the point where it is detected by the victim. In many cases, repeated exposure to bedbug bites leads to more severe skin reactions. In one report, 18 out of 19 victims experienced a skin reaction after bedbug exposure, but usually only after repeated exposures over time. With repeated exposures, the period between the bite and the visible skin reaction decreased from about 10 days to a few seconds. However, there are no typical skin reactions to bedbugs feeding on a person. The symptoms may vary considerably due to numerous factors, including (but not limited to) the number of bedbugs present, duration of the infestation, previous exposure, individual physiological reaction, the species of bedbug, and the skin type of the person bitten.

  1. There are 5 established reactions:
  2. No reaction (due to no or few antibodies produced);
  3. Delayed reaction;
  4. Delayed plus immediate reaction;
  5. Immediate reaction only; and,
  6. No visible reaction. Most human reactions to bedbug feeding consist of a raised red or flat welt which is often accompanied by very intense itching that can last for several days.
Left image: immediate reaction to bedbug feeding after 30 minutes. Right image: reaction after 48 hours 

It is important to recognize that there are many potential causes of itching and irritation other than bedbugs. As a result, the mere present of welts, itching or other skin abnormalities are not a reliable symptom of the presence of these pests. Even dermatologists do not possess the ability to diagnose a bedbug bite. This is of significant importance considering the current frenzy and paranoia about bedbugs in the United States. It is quite probable that pest control companies receive many “false alarms” about bedbug infestations. Cosmetics, allergies, medications, drugs and environmental contaminants all can produce reactions similar to insect bites.

There are 4 general categories of conditions that can cause skin irritations:

  1. Biting arthropods (e.g., insects or mites);
  2. Environmental factors;
  3. Health related conditions; and,
  4. Personal use products.

 Arthropod Bites Confused with those of Bedbugs

Mosquitoes. The typical symptoms of bedbug bites are quite similar to that of mosquitoes but in the case of the former the welts tends to last longer than that of the latter. Mosquito bites (at least those occurring while sleeping) are typically found on the face or other areas not covered when sleeping while those of bedbugs can occur all over the body. Bedbug bites may not become immediately visible and can take up to 9 days or more to appear while those of mosquitoes are typically immediate.

Image courtesty of CDC 

Fleas. Typically, bedbug bites do not have a red dot in the center that is commonly characteristic of flea bites. The red dot is merely due to the fact that fleas have larger mouthparts than bedbugs. A trait shared with flea bites is a tendency towards the pattern of sequential bites often aligned in rows of 3 of more. It is thought that this may be caused by the bedbug being disturbed while feeding and relocating half an inch or so farther along the skin before resuming feeding. Alternatively, the arrangement of bites may be caused by the bedbug repeatedly searching for a blood capillary. Fleas usually bite people around the ankles, producing a small, red, hardened, and slightly raised welt. In addition fleas are most often associated with pets, although the presence of mice, rats, squirrels, skunks, or raccoons can also result in fleas infesting a home. Finally, fleas most often bite humans when their preferred hosts (pets, etc.) are removed from the premise. As long as a dog or cat is present in the house, hatching fleas will bite a dog or cat rather than humans. Obviously, timing as to when bites occur is an important consideration. If someone goes to bed and has multiple bite marks the next morning when they wake up, the likely culprit is bedbugs.

 Spiders. Spider bites are a common complaint. Actuality, spiders rarely bite humans. I am 70+ years old and have never been bitten by a spider. Regardless, spider bites are characterized by 2 tiny puncture marks on the skin that correspond to their paired fangs. Spider bites almost never occur in large number on any one individual. Also, the fangs of most spiders are not large enough to bite humans 

When the brown recluse bites, it is often painless — then skin reddens, turns white, develops a red "bull's–eye," blisters, and becomes painful. Subsequently there is a degree of necrosis or rotting of the tissue. On occasion this spider does not inject venom with a bite resulting in very minimal symptoms. 

Mites. Mites are very tiny arthropods which occasionally infest structures and bite people. In most cases, the infestation can be traced to birds nesting in an attic or on a window ledge. Biting mites are also found on mice or rats. When a bird or rodent dies (or the young leave the nest), hundreds of parasitic mites can migrate indoors and bite humans. Biting mites are tiny but visible to the human eye. The human itch (scabies) mite burrows into the skin and causes intense itching and irritation. Skin between the fingers, the bend of the elbow or knee, and the shoulder blades are areas most often affected by the presence of scabies. The intense itching is accompanied by a linear reddish rash.  

Of course, there are 3 types of lice that infest and bite humans. Generally speaking, the only louse that may be commonly encountered in the West Coast is the head louse. As indicated by their name, these lice occur on the head and cause itching. The nits (or eggs) of these pests are glued to the base of the head hairs. The eggs (see below) are similar in appearance to dandruff but remain attached to the hair. When touched dandruff moves and lice eggs do not.

Chiggers. Chiggers also bite people and generally the biting stage (larval stage) is almost too small to be seen without magnification. Chiggers live outdoors in tall weeds and grass. They crawl onto people and move upward until they encounter a point of constriction between skin and clothing, such as around the ankles, beltline, behind the knee, or at the waistline. Chigger bites produce a hardened, red welt which begins to itch intensely within 24 to 48 hours after exposure to the mite. Consequently, victims may not associate the irritation with the fact that they were bitten while walking outdoors a day or 2 before. Most frequently the bites occur around the ankles or lower legs.

 Insect Repellents. Conventional insect repellents, like those containing diethyltoluamide (DEET) used to deter mosquito and ticks reportedly are not effective against bedbugs. Attempting to avoid being bitten by applying insect repellent at bedtime is not recommended. Sleeping with the lights on is not likely to deter hungry bedbugs.

Means of Home Infestations. There are a number ways how a business, home, hotel or similar structures can initially become infested with bedbugs. One of the most common is to pick them up while staying in a hotel, hostels, B and B or motel. Hotels or accommodations close to popular vacation locations are typically normally at high risk for bedbug infestations due to their continual influx of temporary residents and high rates of client turnover. Once acquired, the now hitchhiking bedbugs may then be transported and brought back to the homes of the guests in luggage, brief cases, jackets or any other items.

Purchases of used furniture or furniture rentals are rather common, especially in poor communities. Of course these undoubtedly help the rapid and repeated spread of bedbugs to new sites and redistribution of them back into places where these pests have been eliminated.

Large multi-unit buildings can be very difficult to rid of bedbugs, especially in low income areas. Bedbugs infest a new residence by traveling between multi-unit housing complexes. This unintentional spread between nearby housing units is dependent to a great degree upon the level of infestation at the initial source. A heavy infestation is more likely to spread than a lower level infestation. Further potential to spread is also directly related to the manner in which infested items are disposed. For example, contaminated furniture should not be dragged through common areas while being removed.

Once bedbugs are well established in a structure, any control effort that does not include inspection of all units, combined with a coordinated program of treatment and occupant education is usually doomed to failure. These pests readily move from any partially treated site to adjacent rooms or floors, especially if repellent pesticides are used. They readily move along utility lines, through wall voids, heating ducts, elevator shafts, and mail or laundry chutes.

Bedbugs can also be brought into structures via acquisition of infested furniture including TVs, computers, microwave or any other small appliances and used clothing. A big problem is delivery trucks. A good example would be someone buys a new bed. It is delivered by a delivery system that in turn picks up the old bed in the same truck. What are the chances of that old bed having bedbugs or at least some of the hundreds of mattresses that truck has picked up having bedbugs?  Sooner or later that truck is going to be infested with bedbugs. It only takes a single impregnated female which is capable of depositing 200 or more eggs to start a new infestation.  Back in the 1940’s, it was not uncommon to treat such vehicle for bedbugs. I am not sure the industry is at that point yet.

In locations that are severely infested, bedbugs may crawl onto an individual's stored or dirty clothes and hence be carried from area to area.  It is also common for bedbugs to hide in clothing articles that are infrequently washed and to then spread when such items are stored publically (in locker rooms, on coat racks, etc.) with other apparel. Typically, bedbugs are not carried from place to place by people on the clothing they are currently wearing. General machine washing and drying on high heat will kill all stages of bedbugs.

The size of a bedbug infestation can range from a few dozen individuals to tens of thousands. A single female bedbug brought into a home has a tremendous reproductive capacity, and bedbug populations can grow quite rapidly (geometrically) depending on prevailing temperatures and the availability of food. These pests reproduce prolifically and it is not at all unusual for applicators to encounter thousands of bedbugs in a single mattress. Sometimes the victims are not aware of the insects and do not notice or even react to the bites. Those bedbugs that are detected in a structure do not represent the entire infestation, as these insect are tremendously secretive and the sighting of 1 bedbug typically means that there may be many more in hiding.

Minimizing Bedbug Infestation in Structures. The first step toward bedbug infestation removal is being aware of likely infestation locations. This will include any place with a high turnover of people spending the night—hostels, hotels near airports, and resorts near popular vacation sites, as well as barracks, apartments, buses, churches, cabins, cruise ships, community centers, dormitories, health clubs, dressing rooms, homes, jets, hospitals, Laundromats, motor homes, motels, moving vans, office building, nursing homes, resorts, schools, dorms, restaurants, subways, trains, theaters, and used furniture outlets. Bedbugs don’t necessarily prefer locations based on sanitation or individuals’ hygiene. The critical component for their survival is food, or put more simply our blood.

Most stay near where people sleep, hiding near the bed, a couch or armchair (if that’s where you snooze)—even cribs and playpens. Their flat bodies allow them to hide in cracks and crevices around the room and in furniture joints. Hiding sites include mattress seams, bed frames, nearby furniture, or baseboards. Clutter offers more places to hide and makes it harder to get rid of them. Bedbugs can be found alone but more often congregate in groups. They’re not social insects and don’t build nests.

Traveling greatly increases the chances of someone bringing bedbugs home. However, there are ways of minimizing the chances of bringing home these pests. Always make a thorough inspection prior to settling into any room. Be prepared and pack a flashlight (even the keychain LED model) to aid in your inspection. Most of the inspection should focus in and around the bed. Start with the headboard.  This is usually held on the wall with brackets. Lift it up a few inches and lean the top away from the wall to access to the back. If traveling alone, request someone on staff to help. In hotel rooms, since the sheets are changed on a regular basis, the bedbugs may avoid the bed to a degree and congregate behind the headboard. After checking the headboard, check sheets and pillows for blood spots. Next, pull back the sheets. Check the piping of the mattress and box spring. Finally, look in and under the dressing table next to the bed and even pictures hanging on the wall next to the bed. If all these places are clear, enjoy the night. The next morning, look for blood spots and fecal spots on the sheets and mattress—bedbugs defecate soon after they feed.

If you find evidence, but no live bedbugs, the evidence may be old and doesn’t mean that the hotel is infested. Discretely tell the front desk what you found and request another room—preferably one that doesn’t share a wall with the room you just left. These pests are a nightmare for the hotel industry. Communication is the key. Ideally, hotels and motels readily discuss their bedbug programs and as a whole are receptive to request of their customers.

Don't unpack if you are going to stay 1 night, or at least don’t unpack your clothing into drawers and leave your luggage on a luggage rack that is pulled away from the wall. Never leave luggage on or near the bed and keep it closed. This is especially true at night. In addition, avoid leaving clothing lying around the room at night.

Launder your clothes (hot soapy water and dryer) as quickly as possible once these items are brought back into the home. If you detected bedbugs subsequent to moving into a hotel room, you could request the hotel to pay for laundering and steam-cleaning your luggage; this may not happen. Regardless, once home you should unpack directly into plastic bags for taking clothes to the laundry. Suitcases should be carefully inspected and vacuumed or left outdoors sealed in plastic bags in the sun. This will quickly kill any bedbugs during hot days.

Inspecting for Bedbugs by Using Dogs. The bedbug, Cimex lectularius, like other bedbug species, is difficult to visually locate due to its cryptic nature. Bedbug detector dogs are useful for locating these pests because they use their sense of smell rather than sight. Reportedly, these dogs are trained to detect the presence of bedbugs (as few as 1) and viable eggs by using a modified food and verbal reward system. Dogs are able to discriminate bedbugs from Camponotus floridanus-Florida carpenter ant, Blattella germanica-German cockroach and Reticulitermes flavipes-drywood termite with 97.5% accuracy. In addition, these dogs are capable of discriminating living bedbugs and viable bedbug eggs from dead bedbugs, bedbug feces and cast skins with 95% accuracy and a 3% false positive rate on bedbug feces. In a controlled study conducted in hotel rooms, dogs were 98% accurate in locating living bedbugs. If trained properly, dogs are now used effectively to locate live bedbugs and viable eggs.

Inspection Procedures. Bedbug inspection procedures vary considerably depending on the extent of the infestation depending. Customer cooperation can be a very useful tool in this process. Client involvement is important when attempting to control these pests.  Especially important are instructions pertaining to premise preparation prior to treatment. Providing access for inspection and treatment is necessary (although difficult to attain) and in many cases, infested items will need to be discarded. A dialog about what to discard is essential. Customers often throw away more than needed. Clutter is a major problem in homes and apartments. Large amounts can obstruct treatment (often making effective treatment impossible) and providing additional places for bedbugs to hide. In uncluttered situations, surveys indicate that 2 or 3 treatments are typically required to attain infestations under control. In cluttered situations 4 or more are often needed. Items must be removed from floors, and furnishings moved away from walls. Some pest control firms request that beds be disassembled or disposed of before treatment in order to minimize the possibility of further infestations.

Bedding and clothing should to be bagged and laundered. With bedbug-infested clothing, a standard wash cycle using hot water will reportedly effectively kills all life stages. This can also be achieved by placing a load of unwashed infested clothing into clothes dryer at high heat (80°C) for 5 minutes. Reportedly, when items are laundered in cold water, about 1/3 of bedbug adults survive as did most eggs.  It is considered poor practice and somewhat selfish to take bedbug infested items to professional dry cleaners or Laundromats.

Correct diagnosis of a bedbug problem is important and the first step of control. Well-established infestations are easy to detect; but in the early stages of an infestation detection can be difficult and time consuming. The presence of welts is not necessarily a symptom of a bedbug infestation. Welts and itches can be caused by bedbug feeding, but they are also often caused by many other factors. 

Most aggregations are located near a sleeping host (most commonly near the head area). But as infestations increase in size, more can be found in various locations within several yards of the bed. Based on a current survey, the most common locations for bedbugs were beds (85% of respondents), bedding (52% of respondents), carpet/baseboard edges (37%), furniture such as dressers and nightstands (26%), chairs and couches (25%), ceilings and walls ((14%), and clothing (6%). A survey of 13 infested apartments in Ohio indicated a similar distribution pattern with 70% of all bugs associated with beds. With inspections of multi-occupancy dwellings, most survey respondents (91%) indicated they routinely recommend inspecting surrounding units next to infested units. This seems to be a no-brainer since it has been pretty well-documented that adjoining units are infested much of the time.

The following check list is helpful when inspecting for bedbugs:  

1)    Furniture, particularly bedroom furniture, must be inspected carefully. Bedbugs may crawl 10-20 feet; so don't limit search only to the bed. 

2)    When feasible, beds should be dismantled for easier inspection (best for the inspector to do so) and possible treatment. 

3)    Inspect the mattress and box spring thoroughly. Be sure to check the holes or slots where sections such as the sides, head and foot boards attach.

4)    Check under and behind other pieces of furniture, such as chairs, couches, nightstands, and dressers.  

5)    Carefully inspect dressers and nightstands (especially near the bed(s); inspect them carefully and check the interior of the dresser before reinserting the drawers.

6)    Examine the undersides of clocks, lamps, radios, phones and other objects located on nightstands.

7)    Pull back the dust covers on the undersides of couches and chairs, especially around the legs and frame.

8)     Inspect objects on walls such as mirrors, pictures, curtains, which are a common bedbug hideout.

9)    Check obvious cracks and crevices along baseboards and pull back carpet from the baseboards.

10)    Remove the covers on electrical outlets and switches and inspect.

11)    Inspect torn or loose wallpaper.

12)    Look behind bed boards. 

Monitoring Devices. There are a number of bedbug monitoring devices on the market. Some are passive (meaning there are no attractants used to draw the bugs to the trap) while others are active utilizing heat or carbon dioxide to attract the pests. There appears to be little information as to the efficiency of the various available models. Two common monitoring device products are discussed below.                                                                                 

The Bedbug Barrier Passive Glue Trap. The Bed Bug Barrier is a monitoring product that attaches to the bottom of the bed legs creating an impassable barrier between the bed and the bedbugs. The Bed Bug Barrier uses natural non-toxic resins and waxes to create an impassable permanent floor barrier that stops bedbugs before they can reach any sleeping victims. The natural glue in the barrier is non-drying, non-toxic, and long lasting. The Bed Bug Barrier is designed to provide long-term protection and also serves as a monitoring tool. There are 2 basic designs. Depending on your bed post design, choose either the screw-in barrier (fits at top of bed legs with glue void facing downward) or the castor barrier (fits underneath bed leg with void facing upward).  

Bed Bug Barrier - Screw-In StyleBed Bug Barrier - Castor Style


The ClimbUp© insect interceptor forms a barrier between the floor and bed. Bedbugs approaching a bed from the room will climb up exterior surface and fall into the outer pitfall ring. Bedbugs climbing down from a bed will be found in center well. These are priced for approximately $3.00 to $6.00 depending on quantity purchased. 

How the ClimbUp for bed bugs works

Other Bedbug Control Methods 

Cold. The use of cold for bedbug control is generally not very effective or cost effective as the use of heat. Bedbugs can withstand 5º F for short periods, and if acclimated can live at or below freezing. Use of cold for treatments of rooms for bedbugs is difficult and not often employed, but freezing various items within containers below 0º F (-19º C) for at least 4 days may be a practical alternative for limited infestations.

Steam. Steam treatments have been used effectively by some to quickly eliminate live bedbugs and their offspring from the seams of mattresses, cloth items and other situations. However, this technique requires training and care. Following instructions is essential with steam generating devices. These include operation of devices, safety and maintenance. The steam tip must typically be held about 1 1/2 inches from the surface being steamed. If held too far away, the steam may not be hot enough to kill the bedbugs and eggs. If too close, excess moisture may be injected into the material being treated which could lead to other problems such as facilitating increases of dust mite population and growth of surface molds. Reportedly the use of steam alone for bedbug control will not kill an entire infestation.

Physical Removal. Bedbugs can be vacuumed from any number of areas or resting sites, such as mattress seams, box springs and cracks and crevices, but bedbug eggs stick tightly to these surfaces and are typically hard to remove.  With a High Efficiency Particulate Arrestance (HEPA) filtered vacuum which will removes >99% of all particles greater than 0.3 in diameter, many bedbug allergen and their debris can also be removed. Vacuuming, especially during the inspections process may remove a significant portion of the pest population and will usually kill some of the bugs. Bedbugs may also be removed from resting sites with the sticky tape, brushing them directly into a container and hand-picking. For those bedbugs that feed chiefly on birds and bats, it is critical to remove all host nesting materials. In addition, heat and/or a bedbug registered chemical can be used to treat the surrounding area.

Sticky Monitors. Sticky traps are an effective tool to monitor many crawling insects and are frequently used to augment other techniques for control of cockroaches and spiders. Although bedbugs will often be trapped on such monitors, some recent reports indicate that they are not very effective in detecting small to moderate populations of these pests. 

Pesticide Applications-Residual Applications

Generally speaking, non-chemical products and techniques are incapable of efficiently eliminating heavy or well-established bedbug infestations. Proper placement of a registered and well-formulated residual insecticide is still considered by most the most practically and effective means of bedbug control. Effective control consists of applying interior sprays and dusts to surfaces that the bedbugs are found or will come in contact with. Dusts and microencapsulated formulations have a longer residual effect than others. Synergized pyrethrins are toxic to bedbugs, produce a flushing effect, and are useful in detecting infestations of these pests. If the product label permits, addition of pyrethrins at 0.1-0.2% to other products labeled for bedbugs including microencapsulated products may increase efficacy of the mix by irritating the bugs, exciting them, and causing them to leave their hiding places. This may increase their potential exposure to the freshly deposited insecticide.

Silica gels, other dust formulations and diatomaceous earth can be of used for crack and crevice treatment. Retreatment should be done after the shortest interval permitted by the label until the bedbug population has been eliminated. The choice of chemical products and specific application techniques can depend on many factors. These may include the physical location and structural details of the bugs’ harborages, the product labels, the immediate environment, and local or national laws.

Crack-And-Crevice Applications. Due to the characteristic behavior of bedbugs hiding clustered together in cracks and narrow harborages, precisely applied crack-and-crevice applications are amongst the most effective techniques for control of these pests. There are a variety of formulations and a number of devices available for applying insecticides to bedbug infested areas. For example, dust formulations can be applied in electrical outlet boxes and in other places where it is desirable to employ low-risk, long-lasting insecticides and to minimize the possible effect of short circuiting electrical devices.

Fumigation. Fumigation of clothing, furniture, or other personal items can be extremely effective in killing all stages of bedbugs. However, such treatments will not prevent reinfestation as fumigants have a very short residual activity. Fumigation of an entire building would be equally effective but, again, would not prevent reinfestation, and rarely is practical and affordable.

Ultra Low Volume (ULV), Aerosols, and Foggers. Insecticides currently labeled for ULV, aerosols and foggers have little or no residual effects on bedbugs. Most will rarely reach cryptic bedbug hiding locations. If directly sprayed into these harborages, some of these products may stimulate a few bedbugs to leave their harborages and move out into the open. Bedbugs are seldom killed by repeated exposure to such products.

Heat. The main battle for survival that bedbugs and other insects have is over the loss of water or desiccation. A small flat insect such as a bedbug has a relatively large body surface area (where water can evaporate from) compared to their total volume for storing water. Their eggs and early instar nymphs are especially vulnerable to high heat due to their small sized and relatively large surface area. Since at least the early 1900s, bedbugs have been controlled by heating infested rooms or whole buildings to temperatures at least 115º F. In order for heat to be an effective tool for killing bedbugs, it is critical that high temperature and low relative humidity be attained for a minimum length of time (generally several hours).In the early 1900s, investigators demonstrated it was possible to destroy bedbugs in buildings ranging in size from a two-story house to a 350-room dormitory on a college campus. Steam boilers and furnaces were used to elevate the temperature in bedbug infested rooms to between 110˚F and 130˚F over a period ranging from several hours to a few days. The process is known as “superheating.” In the first edition of the “Handbook of Pest Control,” Arnold Mallis also mentioned using superheating to successfully de-bug an animal rearing laboratory. He reported that after 8 hours of heating, “the mortality was so terrific that a carpet of bedbugs covered the floor, and a slight draft through the room piled up windrows of the bugs against several objects on the floor.” Efforts to control bedbugs with heat diminished in the 1940s due to the ease of use, economy, and effectiveness of DDT. Interest was rekindled in the late-1980s.

This type of treatment has several pros and cons. Heat treatment provides no residual effect, and bedbugs can re-occupy any treated site immediately after temperatures return to suitable levels. There is the possibility of damages to structures and their contents. Of greatest concern is the possibility of fire. However, the latter is becoming of less concern with the development of a numbers of commercially available safe heat generators. It should be mentioned that initial cost of these heat generators can be quite costly but on the positive side the utilization of heat for bedbug control can be cost effective and if properly applied, can result in total control of these pests including their eggs. The latter is significant since few, if any, of the currently available pesticides will kill their eggs.

Heat can be an extremely valuable tool in removing (killing) all stages of this pest from clothing, sheets, blankets and other linen. Laundering infested items in hot water with detergent followed by at least 20 minutes in a typical clothes dryer on low heat should kill all life stages of bedbugs. A number of pest control companies have now incorporated heat as part of their pest management scheme for controlling these pests. On a commercial basis, the use of heat is especially attractive for smaller structures or units such as college dorms, hotel rooms and individual apartment units. 

Customers do not want to be burdened with the invasiveness of a chemical treatment. Homeowners frequently have to spend hours cleaning out rooms prior to chemical treatment.  Heat treatment offers a form of control where owners only need to remove the items that will be adversely affected by this process.

Reportedly, there is typically no follow up treatment needed for a heat remediation. Depending on the extent of the infestation, pesticide treatment may require several follow up treatments to ensure that all the hidden bugs and eggs have been destroyed. Another big selling point is the turn-around time. Heat remediation only requires that the premises be vacated during the treatment process and for a long enough time for the heat to disperse, generally 24 hours. For a hotel operator, this is a selling point. They can turn the room around in 24 hours and not lose nearly the amount of revenue as they would if they had to undergo a chemical treatment. The most important difference is the effectiveness of heat remediation. Heat remediation kills all the bugs and eggs in a room typically on first application. It is even effective through the walls into the surrounding wall voids of a room. Another plus is that heat remediation is green. In addition, once the treatment is over, the heat dissipates. 

Generally there are 2 types of heat remediation devices: propane powered and electrical powered. Propane powered equipment involves bulky ductwork, leaves residual fumes, and presents a potential fire hazard that can give pause to not only the customer, but also to the pest control operator (PCO) Electrical devices have traditionally been overly large and cumbersome and requiring more than several people to assist in set-up and operation. Many require their own generator to operate.  This is an obvious turn off for any PCO who values his time and money. However, there currently are rugged and robust convection heater designed in a compact form which can be set-up and operated by one man. 

One of the keys to operating these devices is the ability to slowly warm up a treated room. If a room is heated too rapidly, some of the bedbug may escape or be driven from the room. It follows that any heating system should have the ability to monitor the rate of heating up of a location.
Image: a heat generator for bedbug control

True/False Practice Questions.

1. It is thought that bedbugs were originally ectoparasites of bats in caves, but then changed hosts to include humans (cavemen) once they were found in the same habitat.

2. Though bites can occur singularly, they often follow a distinctive linear pattern marking the paths of blood vessels running close to the surface of the skin.

3. Although bedbugs normally venture out to feed in the early morning hours, they occasionally feed at other times if given the opportunity and have been observed active during all periods of the day.  4. Bedbugs are considered an important vector of several diseases of human.

5. One of the possible reasons for the current increase in bedbug problems in the US is the change from using residual insecticides for cockroach control to the use of baits.

6. Once bedbugs become established, any control effort that does not include concurrent inspection of all units in a multiunit facility, together with a coordinated program of treatment and occupant education, is usually doomed to fail.

7. In an infested structure, less than 10% of the bedbugs are typically found on the bed.

8. Sticky traps are an effective tool to monitor many crawling insects and are frequently used to augment other techniques for control of cockroaches and spiders. Although bedbugs will often be trapped on such monitors, some recent reports indicate that they are not very effective in detecting small to moderate populations of these pests. 

9. Insecticides currently labeled for ULV, aerosols and foggers have little or no residual effects on bedbugs. Most will rarely reach cryptic bedbug hiding locations. If directly sprayed into these harborages, some of these products may stimulate a few bedbugs to leave their harborages and move out into the open. Bedbugs are seldom killed by repeated exposure to such products.

10. Bedbugs can also be brought into structures via acquisition of new furniture such as beds, sofas and such.