Cockroaches are a very successful group of
insects with fossil records dating back at least 280 million years. Cockroaches
have flat oval bodies, elongate antennae and heads held so as not to be visible
from above. Their front wings are leathery (tegmina) and may be well-developed
(macropterous), short (brachypterous) or lacking (apterous). In many species
the female's wings are shorter than the male's. Most common species of
cockroaches lay their eggs in cases called ootheca. Depending on the species,
there may be anywhere from 16 to 64 eggs in each case. Primarily, these are
tropical insects, with species in the
Even though cockroaches have six legs they typically only move three at a time. The first and third leg on one side and middle leg on the other side move in unison while the other three remain stationary forming a tripod. Once the three moving legs touch the ground they in turn form the stable tripod and then the first three move in unison. This sequence assures that the roach will always have a stable tripod of legs in touch with the ground even when running. Of course this insures the roach can stop instantly in a dead run without falling-a phenomenon not seen in other animals. A walking cockroach can break into a run simply by increasing the pace of the above sequence. This may all seem pretty unimportant but it is well documented that the cockroach is one of if not the fastest running animals on the earth based on a proportional scale. The American cockroach has been clocked at a speed of 59 inches or 50 body lengths per second. That is about 10 times the number the fastest human can achieve or three times the relative speed of a cheetah. On a relative scale (body length compared actually speed) this equates to almost 150 miles per hour. In order to achieve maximum speed some roaches will spread their front wings thus moving their center of gravid backward and allowing the roach to run on its hind legs only.
Subgenual organs are located at joints on the legs and serve to detect the slightest sound, even the footfalls of other roaches. The tip of each leg is suited with a pair of hook-like structures (tarsal claws) and sticky pads, both of which allow these creatures to crawl up (and even upside down) on most surfaces.
A pair of anal cerci (Figure 10A) is located on the tip of the abdomen. These peg-like structures serve to detect vibrations. A roach may place them on the ground or hold them in the air and readily detect approaching danger.
One of the more important internal organs attributing to cockroach success is the nervous system. A roach is truly a beast with two brains. It has a large paired nerve ganglion in the head and a single ganglion nears the posterior or rear end. These are connected by giant fibers, which carry nerve impulses 10 times faster than normal human nerves. Experiments have shown that a warning input from the anal cerci can be transmitted into leg movement in as little as 0.045 seconds, literally faster than a blink of the eye.
Figure 10A. A South American cockroach with peg-like anal cerci. Image compliments of Entophiles.
Cockroaches are nocturnal (active at night), negatively phototropic (avoid light), and positively thigmotactic (preferring to hide in areas where a surface touches both the top and bottom of the body (Figure 10B). They hide primarily in cracks and crevices. Many species are also gregarious, frequently being found together in non-social groups. It is thought that they secrete pheromones that help them to congregate; the function of these loose groups is not totally understood.
Figure 10B. An American cockroach exhibiting a positive thigmotactic behavior.
Roaches are omnivorous (feeding on all types of food). These insects will eat almost everything humans eat and much more, including feces, book bindings, paste, and any rotting organic matter. Cockroaches have even been found feeding under the toenails and fingernails of patients confined to hospital beds. In some ocean freighters, the roach populations are so large that crew-members sometimes wear socks and gloves to bed to prevent them from feeding underneath their fingernails and toenails.
My wife and I recently witnessed a cockroach’s ability to find and consume food. We sat down to dinner at a well-known restaurant. Right next to our table was a fairly large painting. We decided to have a glass of wine before dinner. Within minutes of arrival of the wine, a German cockroach appeared from beneath the painting and walked out to the middle of our table. Of course, our reaction was not that of normal human beings and we decided to give it some wine. I placed a small drop of wine several inches from the roach which immediately recognized the presence of food through its antennae (smell). It walked over to the drop and tasted it with its maxillary palps. The roach proceeded to suck up the entire drop (which wasn’t much smaller than the roach). It then crawled back to the picture and disappeared. Much to our surprise, within a few minutes the roach reappeared and came back on the table. Of course I gave it another drop and it repeated the entire process of smelling, tasting and consuming the drop. Once finished this time it cleaned its antennae and returned to the picture. A few minutes later the roach dropped from the picture and began to spin on its back. Inebriated? I would think so.
GOOD ROACH-BAD ROACH
In some areas of the world roaches could be considered beneficial. In tropical areas where these insects abound, roaches play a significant role in the recycling of decaying plant and animal matter. For example, in the Amazon jungles a single species of forest floor roach is estimated to contribute to 6% of the turn-over of decaying plant material. In addition these critters are extremely important in many food chains composing a significant part of the diet of carnivores such as birds, lizards, rats and other small mammals. It has also been documented that in many areas of the world some species of roaches are important as pollinators of certain rainforest plants. Actually some roaches, especially the tropical rainforest species, are quite beautiful (Figure 10C). Because of their relatively large size and ease of rearing, roaches are the most commonly used specimens in studies of insect behavior, physiology, anatomy and morphology. Finally some of the larger species (and even smaller ones) have become quite popular as pets in the US and other countries such as Japan. A quick search of the web will reveal many sites that sell these seemingly disgusting critters.
Figure 10C. Some rather striking tropical rainforest roaches. Images courtesy of Peter Chew.
Although in some situations these insects could be considered beneficial, a recent survey conducted by the US Fish and Wildlife indicated that cockroaches were the least favorite animal in the US followed by mosquitoes, rats, wasps, rattlesnakes and bats. With many individuals the mere sight of a cockroach can bring on nausea. One of my recent students who was enrolled in a general education course in entomology indicated that she liked most of the pictures on this CD we used in the class, but that every time the picture of a roach appeared, she ran out of the room screaming.
This fear of roaches is without a doubt a learned response. Studies indicate that children under the age of four typically have no fear of roaches, but older children are typically told by their parents and peers that these critters are disgusting, vile and filthy. A personal note-our kids and grandkids have had repeated exposure to a colony of Madagascar hissing cockroaches that we have maintained for years. Not one of them considers roaches to be disgusting, vile or filthy. Of course from the standpoint of a pest control operator, the fear of roaches is not a bad thing.
The role of roaches in the transmission of disease is well-studied. Studies indicate that about 40 different pathogens are naturally carried by roaches, making them possible suspects in the transmission of diseases such as polio, leprosy, bubonic plague, dysentery, food poisoning, pneumonia, salmonella, typhoid fever and infectious hepatitis, among others.
Certainly the transmission of these diseases is not limited only to roaches. Water, air, hands, flies and any of a number of other ways can also transmit such maladies. Such transmission is referred to as mechanical, meaning that there is no biological association between the pathogen and vector. In the case of roaches transmission is quite simple. The pathogen is transferred from the source to the victim externally on the exoskeleton or parts of the insect. One of many possible scenarios could be a roach lives in a sewer and subsequently moves to human food, thereby moving the pathogen from the source to the food. Another possible means of transmission is through the feeding. When roaches feed they regurgitate partially digested food and frequently defecate near their meal. Again a simple scenario could be a roach feeds on feces (they seem to love it-check your dog feces in your backyard if you don’t believe it)) and then moves on to human food.
The role of roaches causing allergies or asthma is well-documented. According to the National Institute of Health, as many as fifteen million Americans may suffer from roach related allergies. There is additional evidence that roach related allergies may lead to allergic reactions when consuming other arthropods such as crabs, shrimp and lobsters. Such allergies are not due to the insects themselves but due to products of their presences such as feces, cast skins and pheromones. Typical symptoms of roach allergic reactions include runny nose (mild), rashes, labored breathing or in the most severe cases death from shock (rare). Roach allergies are more common in low-income neighborhoods (more roaches) and when people are crowded together under unsanitary conditions and in the northern areas with long winters where individuals are more confined to indoor situations.
Control of pest species is primarily with insecticides; however, proper sanitation is important in preventing cockroaches from reaching pest levels. If food is left exposed to these nocturnal feeders, their populations will increase much more rapidly than if certain precautions are followed. Dirty dishes should not be left on the sink overnight. Any accumulation of grease is especially attractive to these insects, and it is best to store food in "cockroach proof" containers whenever possible. Stored pet food (such as cat food or dog food) should be closed off tightly—preferably in containers with tight-fitting lids. As discussed, cockroaches can feed on paste, bookbinding’s, soap, paper, and other marginal "foods." However, when forced to do so, they generally develop more slowly and have a higher mortality rate. Once established, it is virtually impossible to 'starve out' an infestation. Experiments indicate that roaches can live for up to three months without food and two months without water.
Chemical control is based on the thigmotactic behavior of these insects. Residual insecticides are applied to all cracks and crevices of an infested structure and, when roaches hide during the day, the residues kill the pests on contact. Some of the new synthetic pyrethroid insecticides are extremely toxic to roaches. For example, one month after a surface has been sprayed with some of these insecticides, a roach can die after merely running across it. Then, if the tarsus of that roach is touched to the tarsi of another roach, the second roach will die also.
These chemicals are now readily available to homeowners. It should be noted that these chemicals are selectively toxic to insects; that is, when properly used, they have little effect on humans.
Worldwide there are about 5,000 species, of which only 70 are established in the United States. Cockroaches are extremely successful animals and are thought to have originated more than 280 million years ago. Most live outdoors and prefer a warm, humid environment. In California, four main species are commonly found in the habitats of humans and become pests. These domestic species are the American cockroach (Periplanetia americana), the Oriental cockroach (Blatta orientalis), the Brown-banded cockroach (Supella longipalpa), and the German cockroach (Blatella germanica). All these species originated in the tropics and were introduced into the United States via commercial transport.
American Cockroach. This is the largest of the domestic species, with adults rarely reaching 1 ½ inches in length; it is chestnut brown with light-brown-to-yellow bands around the margin of the top of the prothorax (Figure 10D). This species is also known as the sewer roach, as it abounds there.
Figure 10D. An adult American cockroach with egg case, Periplaneta americana.
The American roach is primarily an outdoor species but may enter homes to feed. The life cycle from egg to adult may require from one to two years, depending on prevailing temperatures. In addition, adults can live up to one year. During this time females will deposit 50 or more egg capsules which contain 16 eggs each. This is the most common species of roach found in sewers in the US, hence the common name sewer roach. It prefers higher temperature and humidity and tends to replace the German roach as the most common roach found in homes in Asia. In the US the German roach is the most common roach found in homes since it prefers lower temperatures.
Oriental Cockroach. This is a large, shiny-black-to-reddish-brown species, about 1 1/4 inches long, which exhibits sexual dimorphism (male and female of a species being distinctly different in form). The females are nearly apterous with very short vestigial wings (Figure 10E), while the males are brachypterous with the wings covering all but the last two abdominal segments. This species is frequently referred to as 'water bugs' because many homeowners are reluctant to admit that they have cockroaches and also because this roach prefers humid environments. This is primarily an outdoor species, but is common in garages and will readily enter other structures at night to feed. A prime location for Oriental cockroaches is water meter holes in alleys. These cavities are dark, humid and undisturbed. The roaches emerge at night to feed in garbage cans and from pet food dishes. The life cycle of this species is quite similar to that of the American cockroach—one generation in as little as one year.
Figure 10E. Left-Apterous adult female Oriental cockroach. Right-Brachypterous male.
Brown-banded Cockroach. This is a smaller species which is about l/2 inch long, brown in color, and distinguished by horizontal tan stripes on the base of the wings behind the prothorax (Figure 10F). The sexes differ in that the male is longer, narrower, and with fully developed wings, while the female is darker, broader and has shorter wings. This species primarily infests buildings and, when in our homes, lives throughout the structure.
Figure 10F. A male (Left) and female (Right) brown-banded cockroach.
German Cockroach. This is the primary cockroach found in homes and restaurants in the United States, with approximately 90% of roach infestations in structures attributed to this species. This roach is about the same size and color as the brown-banded, but can readily be distinguished by two longitudinal black stripes on the dorsal side of the prothorax (Figure 10G). In the nymphal forms, the stripes extend down onto the abdomen. The life cycles of the German and brown-banded cockroaches are similar—species complete development in 60 to 90 days.
Figure 10G. An adult German cockroach carrying egg case, the most common species found in the home.
The German cockroach is unique in that the female carries its ootheca protruding from the abdomen until the eggs are ready to hatch. This is to our advantage when attempting to eradicate this pest from our homes. If a female carrying an egg case is killed, the unhatched eggs also die. Apparently there is an essential contact between the mother and her eggs. Eggs of most insects are difficult to kill with pesticides. Unfortunately, the American and Oriental cockroaches randomly drop their egg cases soon after they are formed. The brown-banded cockroach attaches their egg cases behind objects, such as drawers and picture frames.
The German cockroach has a faster life-cycle and lays more eggs than any of the other common house infesting roaches. As a consequence it tends to increase in numbers more rapidly than these other species. Under ideal conditions this insect can produce three to four generations per year. In addition each female can produce up to eight ootheca which can contain 30 to 40 eggs each. Their reproductive capacity, plus the fact that the environmental conditions that are typically found indoors are ideal for their development lead to their major pest status.
A simple comparison of the potential reproductive capacity of the German and Oriental cockroach (or actually any of the other pest species) will illustrate the difference of each. On average a female Oriental cockroach produces five egg cases containing 16 eggs each and after hatching, the nymphs require a year to grow to adulthood. A simple calculation indicates (assuming 100% survival) that a mated female Oriental cockroach is capable of producing 80 adult roaches in a one-year period. On the other hand a female German cockroach produces an average of eight egg cases containing 16 eggs each, which after hatching complete development in three months. As a result after three months one female would produce 108 adults, half of which are female. In turn those females would produce 5832 adults in another three months. Assuming two more generations after one year, a single female German roach is capable of indirectly producing 17, 006,112 offspring or 212,576 times as many offspring as the female Oriental roach. It should be emphasized that this is a hypothetical calculation and there are many factors that greatly reduce the reproductive capacity of roaches, but it does give great insight as to why the German roach is so much more of a pest than the other domestic species.
During the 1950's and 60's, if a home was infested with German cockroaches, they were almost exclusively confined to kitchens and bathrooms. Over time, infestation gradually began to be seen in different areas of the home; today they frequently are spread throughout the structure. This apparent change in cockroach behavior can be explained by a combination of changes in human behavior and home construction since the 1950's.
German cockroaches prefer environments with high humidity, high temperature and available food. Fifty years ago the family normally sat and ate dinner and other meals together in the kitchen. Today, due to busy schedules, two-income families, and the advent of television, families rarely eat meals altogether or in the kitchen. Consequently, crumbs and other droppings are spread throughout the home and attract these roaches. Higher humidity in the 1950's was typically confined to the bathroom and kitchen. Older homes were usually built with one bathroom. However, bathrooms in newer homes frequently are found in several areas. As a consequence, there is increased humidity throughout the structure. Also, with the advent of central air conditioning, moisture tends to condense in wall voids where the cool room air meets the hotter outdoor air. Finally, there has been a tremendous increase in the number of televisions, computers and other small appliances in homes; these are sources of heat that attract German roaches. Additionally, while sitting for long periods at the computer or television, we often have a little snack (or a full-blown meal). The combination of heat, high humidity and food must be irresistible to cockroaches!
German cockroaches can reach tremendous populations in a fairly short period of time if the right conditions exist. Recently, there have a number of lawsuits throughout the U.S. where tenants are suing slumlords for continuous unsanitary and run down conditions. Large rat and German cockroach infestations are a considerable part of the problem. In some cases, the tenants have actually won the apartment complexes as part of the settlement.
We recently visited one of these heavily infested complexes in Los Angeles. Upon entering one of the units, over a hundred roaches were sitting or running about on the walls. This was quite unusual because it was day time and roaches, of course, are nocturnal. Normally, in structures where roaches are active during daylight hours, it is an indication of a very large infestation as they probably have run out of places to hide. The tenant indicated that conditions had become intolerable: a bowl of food could not be placed on the kitchen table without it being visited by hoards of roaches. On several occasions roaches were found hiding in the ears and up the noses of sleeping children. The ultimate insult was when one of the tenants was feeding her two-year-old and a roach crawled out of the child’s mouth.
If that story grosses you out, I suggest you not read the rest of this paragraph. Recently a doctor friend was examining an extremely overweight lady. She claims that she was examining an area between two flaps of fat on the patient's arm and she first found cookie crumbs and then a few German cockroaches living in this and several other areas of the woman’s body. The doctor was repelled by the finding and required the patient to take a shower before continuing the examination. Although I am sure this is exceedingly rare, it does make biological sense. Such a situation meets all of the biological requirements for this species: food, heat, high humidity and a thigmotactic location.
Madagascar Hissing Cockroach. This roach is an African species that has gained considerable notoriety due to its use in a number of movies (e.g. Damnation Alley, Indiana Jones and the Temple of Doom, and Men in Black). Adults may approach three inches in length and are capable of producing a hissing sound when disturbed (Figure 10H). Contracting the body and expelling air out the trachea (internal breathing tubes) through the slit-like openings of these tubes to the outside produces this noise. This hiss mimics that of a snake and is a startle-defensive mechanism possibly used to ward off attacking predators. Male roaches also use hissing while mock fighting over females. Males can easily be distinguished from females by the presence of two small projections on the prothorax.
Figure 10H. Left. Male Madagascar hissing cockroach with hornlike projections on top of prothorax. Right-Female.
The effectiveness of this defensive mechanism was recently documented in our own home. I brought a box of hissing roaches home from school several years ago. They escaped by pushing open the lid of the box. I assured my wife that they were a tropical species and would not survive in our home. I was proven wrong two years later when we turned over our round oak table and there was a mother and her babies living in the hollow pedestal. Since then, one summer night a loud hissing in the front room wakened us. Upon inspection, our cat was sneaking up on a large roach, only to jump several feet in the air after the pounce of the cat and resultant hiss of a Madagascar roach.
Finally male roaches apparently stimulate female to mate with their hiss. In one experiment the spiracles of male roaches were sealed preventing the ability to hiss. When placed with females these individuals were no longer attractive to females until the sound of hissing roaches was reproduced with a tape player.
Rhinocerus Cockroach. This is certainly one of the largest species of cockroaches in the world (Figure 10I)-perhaps the largest. Their distribution is limited to northern Queensland and reaches a length of 3 ½ inches and a weight of 30 grams (the weight of 2 sparrows). This is a burrowing species that forms permanent tunnels in sandy soil that may reach a depth of several feet. They emerge at night to feed on dried leaves that they frequently drag into their tunnels. As with hissing roaches the young are born alive. They have a very long life cycle and require up to seven years to reach adulthood.
Figure 10I. A giant rhinoceros cockroach.
In Australia they are frequently kept as pets and can be purchased in some pet stores where they are known as macrodogs. They have not reached the pet trade in the US to any extent as it is illegal to export any insects (dead or alive) from Australia. Of course there are always some exceptions to the rule. In this case if insects are captive bred they can be exported.
As with some of the larger insects they are being bred in captivity in Japan and are sold for several hundred dollars each in that country. Insects as pets in Japan have become very popular. I am sure part of the reason is due to the lack of living space and insects take up very little space. In many cases these insect pets sell for very high prices. I had a friend who was doing some work for National Geographic and ran across a new subspecies of a common rhinoceros beetle. He managed to collect 20 pair and brought them back to Japan and sold them to an insect breeder for $10,000 a pair.
Typically cockroach infestations do not appear in the home or other structures on their own. In some situations the Oriental, smoky brown, American and other predominately outdoor inhabiting species of cockroaches may move indoors on their own. On the other hand, the German and brown-banded roaches are nearly always brought into homes by human activity. There are some records of German roaches mass migrating from one structure to another but this is extremely rare. Once established, roaches have the potential to breed to huge numbers in a relatively short amount of time. As mentioned one female German cockroach and her offspring have the potential of producing over a million new roaches after three short generations. Obviously this potential is never reached or we would be literally swimming in cockroaches. A number of factors limit this potential including natural mortality, available space, predators and parasites, availability of food and water and prevailing temperatures and humidity to name a few.
The presence or absence of these factors becomes very important in cockroach control. All structures have a limited capacity (carrying capacity) to support a certain number of cockroaches. Biological factors attempt to keep an insect population at that level, regardless of measures taken to reduce the population, like pesticide applications. For example when a number of cockroaches die after an insecticide application, the reproductive rate of the remaining roaches will increase to replace those individuals and keep the population near the carrying capacity.
An important phase of cockroach control is to attempt to reduce the carrying capacity of an infested structure. In some cases the pest control operator will not be able to accomplish this on his or her own, but he or she can educate the client and thereby increase the chance of successful control.
The most important factors that can be controlled to reduce the carrying capacity of a structure are the availability of food, water and space. A very small amount of water (much less than a drop) is all that is needed to maintain a cockroach for weeks, if not months. Any source will suffice including condensation on pipes, small leaks, moist sponges, soaked wood or even moist food. Cockroaches eat almost anything, including: crumbs, hair, fingernail clippings, feces, paper, spots of grease, oiled clothes, pet fur and dead insects (even dead cockroaches). They will cannibalize their own young and egg cases if food becomes scarce. Food high in protein or containing significant moisture content is very attractive to cockroaches. However, if forced to feed on less nutritious food such as wood, soap, fingernails etc. their natural mortality rate will increase.
As previous discussed, domestic roaches are positively thigmotactic meaning they hide during the day where they have a surface touching the top and bottom of their bodies. This normally equates to crack and crevices that are around 1/16th inch wide. They also prefer to sit on wood and paper rather than metal surfaces. Their flat body allows them to squeeze into places where they can touch the surfaces above and below at the same time. Additionally the warmth around motors of dishwashers and refrigerators is attractive, especially if there is a drip pan under the refrigerator which provides water. In summary, one of the aims of a successful pest control program should include the reducing the availability of those factors (discussed above) that determine the carrying capacity of a structure.
Limiting the Availability of Water
Plumbing. Of the factors discussed above this is probably the most important in reducing cockroach populations. As with humans roaches can survive much longer without food than they can in the absence of water.
Other Water Sources.
Damp dishrags or sponges are an ideal source of moisture and even bits of food. These can be rinsed with a mild ammonia solution or placed in a plastic bag. Potted plant dishes with standing water or even moist soil in plant pots can be a source of moisture. A layer of gravel over the soil will eliminate the latter sources. Other sources of water could include pet water dishes and refrigerator pans.
Limiting Food Supply.
Sanitation start with a through clean up of the cooking area. This starts with cleaning behind and under the stove, refrigerator and freezer, if present. The outside of the appliances should also be cleaned. A tremendous amount of food refuse accumulates under the stovetop. Particular attention should be paid to any accumulation of grease which is roach caviar. Cockroaches readily feed on the film of grease on oven hoods and walls next to or behind where frying pans, or grills are used.
When possible foods should be stored in cockroach proof containers. This isn’t as simple as it seems as these beasts can chew their way through most types of packaging including thin soft plastic, aluminum foil, paper and cardboard. No open food should be left out overnight, especially on dirty dishes in the sink. It is difficult to completely deprive cockroaches of a food source, but limiting food resources makes it easier for other control methods to work effectively.
Unlike humans roaches make no distinction between garbage and a gourmet meal. A garbage disposal is very helpful in reducing waste in the home. However, the garbage disposal must be used daily or whenever waste is deposited, and it should be flushed thoroughly after each use. If a top cover to the drain leading to the disposal is available this should be in place when not in use. All food preparation surfaces, pots and pans and dishes should be thoroughly cleaned as soon as possible after eating but certainly before retiring.
Eliminate Hiding Places.
Keep in mind roaches prefer to be in tight, small places and to rest on porous surfaces such as wood, cloth and paper. Stainless steel, aluminum, plastic laminates, ceramic tiles or baked enamel surfaces are less preferred for resting. When these "soft" materials are layered (such as corrugated cardboard), it forms an ideal site for cockroach resting and breeding. Do not keep paper bags, sacks, cardboard boxes, rags or pieces of wood in locations where cockroaches may be present. One of the biggest mistakes is to store paper sacks next to the refrigerator because it provides a layering effect next to a warm area and high source of humidity. Equally troublesome is the storing of paper bags in layers in kitchen drawers.
Ideally narrow cracks, seams and crevices should be sealed in order to reduce the hiding places of roaches. Frequent hiding places include behind molding, small holes, around rubber gaskets on refrigerators and freezers, in seems beneath kitchen tables and where cabinets or walls meet, or around built-in appliances. Caulking is the most commonly used method to seal most of cockroach hiding places. Of the various types available silicone caulks are preferred as they do not shrink, crack and cannot be chewed through by roaches.
Inspecting for Infestations.
The first consideration in inspecting for a cockroach infestation is to identify the roach or roaches you are dealing with. Once identified then the knowledgeable operator will have a better idea as to where he or she would likely find the roaches. For example German roaches and brown banded roaches may be spread throughout the house and Oriental and American roaches are more likely to be found outdoors or in warm moist situations in the home. One of the chief tools is a good flashlight, which is needed to examine those hidden dark locations where roaches are likely to occur. Also a long handles mirror may be of use in checking those hard to reach locations.
Chemical control becomes more difficult for the homeowner as opposed to the professional exterminator. The main advantage the professional has is the range of products available. However there are effective products available to the homeowner. It is important to read the pesticide label before selecting a product and precisely follow its directions when using any pesticide product. Most importantly the product should be developed for roach control and should have some residual activity, meaning once it is applied it should remain active for days if not weeks at least. It is not important to apply the chemical directly to the roach but more important to apply it to where the roaches hide during the day. Keep in mind that roaches are positively thigmotactic and hide in cracks and crevices. Generally speaking roach motel type products and aerosol bomb are not that effective in this offers opinion.