CHAPTER 2

COCKROACHES

Learning Objectives

After completion of the study of Cockroaches, the trainee should be able to:

Cockroaches have survived for more than 300 million years. Ancient fossils had the same appearance as today's cockroaches: oval and flat with long legs and antennae. The modern cockroach has the same need for a warm, moist climate. Worldwide there are 3,500 kinds of cockroaches. While most live wild in the tropics, a few, called urban cockroaches, choose to enjoy the moist, even temperature humans maintain in their homes and workplaces.
Applying pesticides where and when the insects can be found allows technicians to manage control measures most effectively. Knowing similarities and differences are important clues. [Communicating this knowledge, will give clients more confidence in the professional ability of their pest controllers.] By considering the habits discussed below, the applicator can begin to consider effective measures to control cockroaches. Except for size, all cockroaches are relatively similar in overall shape and appearance. They are nocturnal and stay in the dark whenever possible. [When they are seen in the open or in the light, it usually means that a large infestation is present.] Cockroaches also like tight places where their bodies can touch surfaces both above and below. As they grow to adulthood, they will seek varied harborage (living space) to accommodate their increasing size. Cockroaches are particular as to where they live. They do not uniformly infest one room or all rooms.
     The five most common kinds of cockroaches found in urban areas in the United States (listed in order of frequency found) are the:

German Cockroach

Blattella germanica The German cockroach is not only the cause of the largest number of phone calls requesting pest control, but also represents the largest number of control failures of any household pest. It is most successful at infesting human structures and withstanding pest control activity. Pest control technicians will need to double their efforts in analyzing every German cockroach infestation, and should be prepared to use more than one technique to bring the infestation under control.

 Appearance
Adult German cockroaches are 1/2 inch long or slightly longer. Males are grayish-tan with two black stripes on the pronotum and have a tapering abdomen. Females are usually darker and their abdomens are more rounded.    
    Nymphs are sometimes not recognized as cockroaches; they appear quite different than the adults. After molting, they will be ivory white for several hours before turning dark. People who see them at this time often think they are albino cockroaches. [Actually, such observations mean that the cockroach population is so large, the nymphs cannot find unoccupied spaces in which to hide and molt, for they normally leave their aggregations to molt in private.] In the first stage, nymphs are very dark. In later stages, a pale tan stripe appears down the middle from front to rear. This stripe divides the nymphal markings into two dark, long stripes. The stripes remain as two dark streaks on the adult's pronotum while the rest of the body is covered by the tan or brown wings.

Life Cycle
Eggs. The egg capsule of the German cockroach is about 1/4 inch long. Half of it protrudes from the female's abdomen. It is carried in this way for three weeks until it is dropped, about one day before the eggs hatch. The drop usually takes place in a secluded portion of the infested habitat. [If the egg case is dropped much more than one day before hatching time, the young die.] Each egg capsule contains 30?40 eggs. Altogether, the female will produce from four to eight capsules in her lifetime. Four capsules will have Module One, Chapter 2, Pg 2 a full complement of eggs, but subsequent capsules can contain less.
    When the female goes into safe hiding, she takes the capsule with her, reducing exposure to possible harm. In extreme danger, she will detach the capsule and flee. The capsule has a relatively impervious surface to protect its eggs. It does, nonetheless, receive moisture from or give moisture to the female. In extremely dry atmospheres, however, the female will abort the egg capsule. In all large infestations, there are egg capsules present. Even if the cockroach population is eliminated, as many as one in every twenty egg cases can still hatch.
   Nymphs.
The eggs hatch when the nymphs inside create pressure that splits the case and allows the young to escape. They often will stay around the opened egg capsule after hatching. Then, as they develop, they molt six or seven times before reaching the adult stage. Females often have one more molt than males. When molting, nymphs are very soft and vulnerable.

German cockroach nymph

Adults.
Adult cockroaches emerge from the last nymphal molt fully winged. They join a nearby aggregation made up of other adults and larger nymphs. The aggregation is held together by a very short-range odor called the aggregation pheromone.

Behavior and Harborage Aggregations of cockroaches live in areas of high humidity and nearby food. They will find harborage into which they can fit closely. As the number of roaches increase and favorable harborage is filled, roaches are forced to leave the aggregation or remain in less favorable harborage. They will find these new sites during their foraging periods just before dawn and after dark.
Aggregations:

CONTROL AND MANAGEMENT of the German Cockroach
Inspection
    With Flashlights. An active flashlight inspection is the most intensive method of locating roaches. The technician can search dark, undisturbed, or remote places of roach harborage that a client may have thought too inaccessible.
    With Traps. Passive use of sticky traps is a common inspection or monitoring method used for roach detection. Correct trap placement depends upon the applicator's understanding of roach foraging habits: for instance, jars and traps baited with fermenting materials such as beer, bread, potatoes or softened raisins indicate population size, but are not especially helpful for finding harborage. Hand mirrors, magnifying hand lens, or other small tools may be helpful to some technicians.

Habitat Alteration
      Speak to clients in a friendly, knowledgeable way. Technicians should explain that changes can be made that will alter or eradicate the insect problem. These recommendations should include how clients can eliminate or restrict material that supports roach populations.

Pesticide Application In attacking roaches, concentrate on injecting pesticides into active harborage rather than  preventively treating uncertain harborage.

Follow-up
A technician should record the data collected with each activity. Such information is not only helpful in understanding the problem over time, but with providing clear communication with clients.

BROWN-BANDED COCKROACH
Supella longipalpa
Brown-banded cockroaches are not generally as widespread as the German cockroach, but where they find favorable harborage, such as warm apartments and overheated office buildings, they build up infestations rivaling the German cockroach. They can be found across the United States.

Appearance
Adult brown-banded cockroaches are the size of German cockroaches -- about 1/2 inch long. The female is a little longer than the male. Her wings are reddish-brown to dark-brown, and a little shorter than her broad, rounded abdomen. The male, slightly less than 1/2 inch long, has wings that are dark-brown at the base but light-brown at the tips, which are slightly longer than the tapering abdomen. Both sexes have a light band behind the pronotum. at the base of the wings, and another or partial band about one-third of the way back from the pronotum. The pronotum. is dark-brown with very light side margins and never shows two stripes as the German cockroach does. Nymphs are dark with two very light bands separated by a dark band just behind the pronotum. These nymphal markings are more obvious than the banded markings of the adults.

Life Cycle
Eggs. The brown-banded cockroach female forms an egg capsule and carries it less than two days when she glues it to an object in the harborage site. The capsule is very small, only about 1/8 inch long, and a little less than 1/8 inch wide. It is oval and light tan to brown in color. The female usually glues these in clumps underneath furniture, behind kitchen cabinet drawers, and in corners inside cabinets and cabinet frames. These capsules hatch in around 50 days; they take longer at cooler temperatures (e.g., up to 95 days at a room temperature of 72 degrees Fahrenheit). A female may deposit 14 egg cases in her lifetime; 13 to 18 nymphs can hatch from one egg case.
A parasite of the brown-banded cockroach egg capsule is a small wasp, Comperia merceti. A female wasp seeks dark areas where she can find brown-banded cockroach egg capsules in which to lay her eggs. The tiny wasp larvae eat the roach eggs, then emerge from the capsules, fly to windows where the sexes meet and mate -- and the cycle begins again. This wasp parasite has been used as part of a cockroach pest management program.
Nymphs.
     Nymphs molt six to eight times before becoming mature for a total of five to six months at around room temperature. At higher temperatures the nymphal period is nearly halved.
Adults.
     Adult brown-banded cockroaches live about six months past the nymphal stage. Males fly readily, as can be seen when lights are turned on during their foraging periods. The females do not fly.

 Behavior and Harborage
     Brown-banded cockroaches, like German cockroaches, build up the highest populations in kitchens. Their tendency is to flourish in apartments and homes where high temperatures are maintained. They frequent high cabinets and favor areas near stoves and warm motors, such as those in refrigerators, electric clocks, light timers, televisions, and radios.

Control and Management Inspection
Search areas frequented by the brown-banded cockroach. Look for roaches and egg cases. Habitat Alteration Apply caulk around pipes and other wall penetrations. Where possible, suggest that the client clean and replace shelf paper and drawer liners, reduce clutter, and consistently remove garbage before nightfall. Eating in non-dining areas should be discouraged. Pesticide Application Do, Use a narrow diameter extension tube in infested cracks and crevices to provide a thorough application of residual insecticide: under furniture, drawers, sinks, around pipes and high cabinets. First remove utensils and supplies in cabinets; do not treat shelf surfaces. Consider pesticide formulations not readily absorbed by unpainted wood. Bait stations with a long active period are effective, but should not be contaminated by sprays or dusts that may be repellant. Place an adequate number in or very near harborage. 10. Spot sprays often break down before egg capsules hatch. NO. Space sprays lack crack and crevice penetration. No pesticide application used alone will control roaches satisfactorily without habitat alteration. Follow?up The long egg hatching time of the brown? banded roach requires treatments to be monitored and followup provided treatments, if indicated. 

AMERICAN COCKROACH Periplaneta americana The American cockroach is cosmopolitan and is often cited in historical accounts. Its worldwide distribution has been aided by its ability to thrive aboard ships. Like the Oriental cockroach, the American cockroach is sometimes called Waterbug. In the southern United States, it is called Palmetto bug. Appearance Adult American cockroaches are long: 1 1/3 to 1 1/2 inches. The wings of the male extend slightly beyond the tip of the abdomen, but those of the female do not. This roach is reddish? brown in color, and its pronotum is ringed by an irregular light color that is almost yellow. Often this margin is bright and wide, darkening toward the center of the pronotum. In other cases, the lighter margin is barely discernible, but it is always present on the rear margin of the pronotum. Life Cycle Eggs. The American cockroach female drops her egg capsules about one day after they form. The capsules are only about 5/16 inch long and 3/16 inch wide, and are sometimes covered with dust, because they are left by the female in out of the way places. [Egg capsules that are clean, dark, and often dropped in the open, are an indication of a high population.] Where climate allows American cockroaches to spend most of their lives outdoors, egg capsules can be found in moist wood. Although females produce egg capsules throughout the year, they produce more of them in the summer. An egg capsule can form in about one week, so from 12 to 24 capsules can be produced in the warm months. An average of 14 eggs per capsule hatch in 30 to 50?plus days. Nymphs. When they first hatch, nymphs are gray. After their first molt, they are reddish-brown in color like the adults. They molt up to 13 times before reaching adulthood. Depending on temperature nymphs can take from six to 20 months to mature. Mature American and Oriental nymphs can be difficult to tell apart. Adults. Adults commonly live more than one year, giving the American cockroach an entire life span of 20-21 months. Flying American cockroaches are found only in the southern United States.

Behavior and Harborage
Large populations of American cockroaches live in warm moist habitats. They can be found outdoors in the southern United States in alleyways, dumps, stacked firewood and rotting wood, and in tree canopies as far north as Maryland. [they winter in landfills of decaying trees at that latitude.] In the North, they can be found in boiler rooms or other harborage with water heaters, floor drains, water sumps, and warm moist basements. 

Control and Management Inspection 
Search areas that provide warmth and high humidity. 

Habitat Alteration 

Pesticide Application

Follow-up
Ongoing monitoring is important due to the long life span of this roach.

ORIENTAL COCKROACH Blatta orlentalis 
The Oriental cockroach is often called the waterbug, and sometimes the black beetle, or just plain, beetle. It is the most common urban roach in England. 
Appearance 
Adult Oriental cockroaches are very dark-brown or shiny-black. The female is slightly longer than the male -1 1/4 inch to his 1 inch. Unlike other domestic cockroaches, the female does not develop wings, but produces only short triangular wing pads. The male has wings, but they are short and broad, leaving about 1/4 of the abdomen exposed.

Life Cycle
Eggs. The Oriental cockroach female produces an average of eight egg capsules from spring to midsummer. Unlike other urban cockroaches, the Oriental roach produces only one generation per year where temperatures are cool in winter. The egg capsule is carried for little more than 24 hours, and then is placed in a protected spot; it is irregularly shaped, black, 3/8 inch long, and 1/4 inch wide. Eggs hatch in two months.
Nymphs. 
Nymphs are active from about March through much of the summer. During this period they molt seven to ten times, and are reddish-brown to black in color, except in the first stage when they are pale tan. The older brown Oriental cockroach nymphs are very difficult to distinguish from the American cockroach nymphs. 
Adults. 
In early spring, only adult Oriental cockroaches are found. By late spring, nymphs are abundant. As nymphal numbers increase, the adults die off and by August any adults are new ones. By fall, almost the entire population is adult. Neither males nor females fly. Behavior and Harborage Oriental cockroaches favor crawl spaces, spaces between the soil and building foundations, the undersides of stoops and sidewalks, landscaping mulches, water meters, basements and their floor drains, and other such moist places. These cockroaches frequently live in floor drains that drain directly outside; these drains are also used as entrances to homes. The Oriental cockroach prefers starchy food, and builds up populations around garbage cans. They tolerate lower temperature ranges than other roaches and may winter in rock walls or such protected sites. These cockroaches are more sensitive to lack of water than other roaches.
Control and Management Inspection
Search areas of high humidity.
Habitat Alteration

SMOKY-BROWN COCKROACH Periplaneta fuliginosa

The Smoky-brown cockroach is a relative of the American cockroach and resembles it in size and shape. These cockroaches are more common in the southern United States and are not found in all parts of the United States.
Appearance
Adult Smoky-brown cockroaches are slightly over I inch long, and both sexes have wings that are longer than the abdomen. Their very dark-brown mahogany color is striking; no light markings appear on the pronotum or wings. 
Nymphs, like adults, are also dark-brown. Antennal tips of young nymphs are white, and the base segments of the older nymphs' antennae are white.

Life Cycle Eggs. 
The egg capsule of the Smoky-brown cockroach is large and dark-brown. The female usually glues it to objects in the harborage. An average of 17 eggs are in each capsule; as many as 24 eggs have been found. Nymphs hatch within 50 days. Nymphs. Nymphs hatched in summer over-winter. Adults. The life cycle of a Smoky-brown cockroach is about one year. A large adult die-off occurs each fall. Both sexes fly. Behavior and Harborage The Smoky-brown roach is found in the Gulf States from central Texas to Florida, in Georgia, South and North Carolina, southern California, and in some parts of the mid-west. It is a plant feeder, and occurs in greenhouses. While it is mainly an outdoor roach, it is often transported indoors. Populations build up outside homes and enter around doors, garages, and in the eaves of roofs [where they live in gutters and under roof shingles and easily find their way into attics]. This cockroach is very dependent on moisture. With the high humidity of coastal areas, populations can build up and infest every level of a structure.

 Control and Management Inspection
Search gutter and roof overhang and attics.
Habitat Alteration

Pesticide Application

Follow-up
Monitor especially in unoccupied vacation homes. Attics of all infested homes can be heavily infested, especially unoccupied homes.

BROWN COCKROACH Periplaneta brunnea
The Brown cockroach, another close relative of the American cockroach, is transported in plant soil.

 Appearance
The brown cockroach closely resembles the American cockroach in color but lacks the light coloration on the margin of the pronotum. Its cerci (short appendages at the end of the abdomen) are wider and have blunt tips; the American roach has slender, pointed cerci. It is not as uniformly dark as the Smoky-brown cockroach.

Life Cycle Eggs.
Egg capsules of the Brown cockroach are over 1/2 inch long and contain an average of 24 eggs. They average 35 days from deposition to hatching. Nymphs. Nymphs mature in little over nine months. The antennal segments of the first nymphal stage are white both at the base and tip.

Adults.
 Adults are associated with trees and feed on plant materials. This species has a somewhat yearly growth cycle.

Behavior and Harborage
The Brown cockroach is found from eastern Texas to Florida. They build up large populations in some areas. They live outdoors, but enter homes on occasion, and they often are transported into new areas with the movement of plant soil. Brown cockroaches can be found on the trunks of palm trees and in places such as sewers, crawl spaces, and garages.

Control and Management Inspection
Pay careful attention to outdoor populations near buildings. In areas outside the Gulf Coastal region, inspect shrubs and trees that have been imported for indoor use.

Habitat Alteration See American Cockroach.

Pesticide Application

Follow-up
Continue monitoring until the population is eradicated where these roaches occur inside.

AUSTRALIAN COCKROACH Periplaneta australasiae
Another relative of the American cockroach, the Australian cockroach, is introduced (brought in from outside the continental United States) and rarely found out of doors in the United States except in the Florida Keys.

Appearance
The Australian cockroach is similar to the American cockroach in appearance but is slightly shorter and somewhat oval. Australian cockroach adults have conspicuous light-yellow margins on the pronotum. The reddish-brown base color is slightly darker, and the outside edges of the wings just behind the pronotum are light-yellow, sometimes nearly white.
Nymphs are brown but have yellow streaking across each thoracic and abdominal segment.

Behavior and Harborage
The Australian cockroach is more commonly introduced with trees and other plants used inside shopping malls than the Brown cockroach. It burrows into soil and is not easily detected. The Australian cockroach can build up in large numbers in buildings with high humidity.

Control and Management Inspection

 Pesticide Application

SURINAM COCKROACH Pycnoscelus surinamensis The Surinam cockroach is another hitchhiker in plant soil and infests plants used in building interiors. Appearance The adult female is about one inch long, and has a shiny-black head and pronotum, with uniformly dark-brown or sometimes lighter-brown wings. No males are found in the United States.

Behavior and Harborage
The species is established in southern Florida and Texas.

Control and Management

Plants may need to be removed and treated elsewhere.

The last cockroach species listed here can be very difficult to control when they become established in areas that import tropical plants to simulate rain forests and other tropical ecosystems. This is particularly so when tropical birds and other animals are also part of the system.

WOODS  COCKROACH Parcoblatta pennsylvanica

This is the most common species of Woods cockroach among the several that exist. They all live outdoors exclusively.

Appearance
The adult female is slightly less than I inch long, and her short wings cover less than half of her abdomen. She cannot fly.
The male Woods cockroach is one inch long, and has richly-colored, dark-brown wings that extend well over the tip of his abdomen. The woods cockroach is slender (three times longer than wide). The pronotum and fore-part of the wings of both sexes are margined with light yellow or white, but the pronotum is very dark between these margins.

Behavior and Harborage
Woods cockroaches live in rotted logs, tree stumps, hollow trees, stopped-up rain gutters, under loose bark of trees, and in piles of firewood. The males fly to lights, landing on windows and door screens. They then make their way indoors or fly into the house. Sometimes they are brought in with firewood. However, once indoors, Woods cockroaches soon die; human habitats do not provide the moisture of their normally shaded woodland. Even with sufficient moisture they would not live long without females. Woods cockroaches range across the southern, mid-western, and eastern United States into Canada.

Control and Management
Male woods roaches can be excluded by caulking and tightening around screens in rooms that face woods habitat. Outside lights that attract flying roaches can be regulated. Nearby windows and doors where light-attracted roaches may enter should be tightly screened. No pesticide applications are needed.

ASIAN COCKROACH Blattella asahinai

Appearance
The appearance of the Asian cockroach is identical to the German cockroach.

Behavior and Harborage
The Asian cockroach is essentially an outdoors roach; its populations are seasonal. It is native to and widespread in southeast Asia and other parts of the Pacific, but it has successfully colonized urban neighborhoods after being introduced into the Tampa, Florida area of the United States. This roach lives outside and builds up under fallen leaves and ground cover. It favors shady, moist areas, and builds up rapidly under trees. Unlike most roaches, it is attracted to light, and adults fly to lighted windows, doors, yard lights, and parking lot lights at dusk. From these points they often crawl into buildings or fly to indoor room lights. The Asian cockroach begins building up its population in spring, and produces several generations through the summer. It is limited to warm and moist regions, and may become a serious problem in areas of the United States Gulf Coast where the climate permits it to begin a population increase earlier in the year.

Control and Management
Inspection
Inspect large yard trees and waste areas next to suburban yards. Locate favorable harborage.

Habitat Alteration

Attractive blue or cold lights should be located away from buildings and directed so they do not shine on the building walls.

Pesticide Application

Before migration to lights begins, apply pesticides labeled for use on cockroaches to populations in favored harborage outdoors.

Follow-up
Monitor to find when populations begin to increase.

SUMMARY
Four factors explain the success of the German cockroach as a pest in human habitations:

German cockroaches in particular live on the same wide range of food that humans eat, and have no strict preferences that would limit them to periodic scarcities that might endanger their numbers. Accepting many different foods shortens not only foraging time, but foraging distance as well. German cockroaches build large populations quickly. They produce a large number of eggs per capsule and have a shorter developmental period than other domestic cockroaches. Urban cockroaches are adaptable. Generally, their rapid population growth allows for increased variation in each generation. In terms of pesticides, this means that some individuals can chemically break apart a pesticide in their body rendering it ineffective. When these roaches mate, some pass this ability on to some of their offspring, resulting in a population with increasingly larger numbers resistant to the pesticide.

STUDY QUESTIONS FOR MODULE ONE CHAPTER TWO
COCKROACHES

1) The cockroach that requires the most control effort is the
A. Asian
B. American
C. German
D. Australian

2) American cockroaches like an environment that is
A. Slightly cool, moist
B. Very warm, moist
C. hot, dry
D. lukewarm, average humidity

3. Oriental cockroach populations consist mostly of                           in the winter.
A. adults
B. nymphs
C. eggs
D. pupae

4. Cockroaches need                       to be successful.
A. food, moisture, harborage
B. food, moisture, open spaces
C. warmth, food, cracks
D. cracks, crevices, food

5. Oriental cockroaches prefer a                                 environment.
A. moist
B. warm
C. high
D. small

6. Brown-banded cockroaches prefer a                             environment.
A. cool
B. very warm
C. sanitary
D. very moist

7. Smokey brown cockroaches prefer a                            environment.
A. open
B. very warm
C. very moist
D. high

8. German cockroaches have
A. two bands across their thorax
B. two stripes on their thorax
C. light markings on their thorax
D. short wings.