IDENTIFYING COCKROACHES IN AND AROUND THE HOME

 

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IDENTIFYING COCKROACHES IN AND AROUND THE HOME


One of the most common insects found in and around man-made structures is the cockroach. The cockroach is often labeled as a repulsive, filth-carrying, food-contaminating creature. Controlling cockroaches in and around the home is a continuous battle. If effective, economic control is to be achieved, we must be able to positively identify the species that we are dealing with.


INTRODUCTION

It has long been said that the cockroach is one of the most successful and adaptive organisms on earth.

Cockroaches are one of the most ancient of all insects. Fossil evidence indicates that they have been on earth for over 300 million years. When compared to the cockroach, man has been around for only the blink of an eye. More than 200 species of fossilized cockroaches have been found in North America and Europe. Several species have been found in Baltic amber.

At the present time more than 4,000 species of cockroaches have been described and named. Close study of fossilized cockroaches has revealed that very little change has occurred in the cockroach over time. The present day species are very much like their ancient ancestors.

The cockroach's nearest relatives include the grasshoppers, crickets and mantids. A distant cousin of the cockroach is the termite.

Cockroaches are world wide in distribution. Most species are found in the tropics. In the U. S. A. we have 49 native species and several introduced species. Most of these are found in the southern states. 

TELL ME

  1. In what part of the world are most species of cockroaches found? .
  2. How many species of cockroaches are native to the U. S.? .
  3. Fossilized cockroaches have been found that are about million years old.
  4. Name two close relatives of the cockroach.
    and .


LIFE HISTORY AND HABITS

DESCRIPTION

The name cockroach is thought to have been derived from the Spanish name for the insect, "cucaracha". Many of the most common species have an accepted common name, and some have one or more aliases.

Cockroaches range in size from a fraction of an inch to several inches in length. Their color in generally brownish to blackish, but some are yellowish, tan or green. A few species are marked with spots or stripes of bright red, yellow, black and even metallic colors.

Cockroaches are flattened dorsoventrally, or from top to bottom. They are oval to oval-elongate in shape and are often described as being "football-shaped". Their head is often partially or totally concealed by their large shield-shaped pronotum. Their legs are relatively long and are often very spiny. Their antennae are long and filament-like. Their mouth parts are well developed for chewing.

Most cockroaches have two pair of well developed wings. The front pair of wings (forewings) overlaps over the back. They are narrow, thick and leathery. The hind pair of wings are membranous and are folded fan-like beneath the front pair. Many cockroach species are wingless and others have only rudimentary wings. In some species, the females have wings that are shorter than the males, and they may appear so different that they can mistakenly be taken as being two different species.

Cockroaches have two tail-like appendages at the posterior end of their abdomen. These structures are called cerci. The cerci are very prominent in the nymphs, but in the adults they are often covered by the wings and are not visible from above.

Immature cockroaches resemble the adults except they do not have wings, and they are smaller in size.

DEVELOPMENT

Cockroaches develop through gradual metamorphosis. They have three distinct life stages. These are the egg, nymphal and adult stages. Females lay eggs that are enclosed in capsules called ootheca. Each ootheca may contain from just a few to about 40 eggs depending upon the species. Each female may produce from less than ten to more than 50 ootheca in her lifetime. The ootheca is carried at the end of the abdomen of the female until it is hardened. This is usually one or two days. It is then deposited. The ootheca are usually attached, or glued, in secretive places, to a structure or object. Each species has its own preferred oviposition sites. Some species will carry the ootheca at the end of their abdomen and not deposit it until the eggs are ready to hatch. Depending upon the species, the nymphs begin to hatch in about 30 to 90 days.

The nymphs go through several molts. Each time they increase in size and look more like the adults. Some species of cockroaches may complete a life cycle in about 60 days. Other species require about three years. The number of offspring from one female cockroach, in a single year, may range from several hundred to several thousand, depending upon species.

NOTES

In some species of cockroaches the females have wings that are shorter than the wings of the male.
Some species of cockroaches are wingless and some have wings that are not fully developed, or rudimentary.
The life cycle of the cockroach may be completed in 60 days in some species, but it may take as long as three years in other species

 

TELL ME

  1. The shield-like structure on top of the cockroach, located just behind the head, is called the .
  2. The front wings of the cockroach are also referred to as the wings.
  3. The tail-like appendages at the end of a cockroach's abdomen are called .
  4. Cockroach eggs are incased in a purse-like capsule called .
  5. Cockroaches have gradual metamorphosis. Therefore they have three developmental stages.
    These are the , and .


HABITS

Although most cockroaches are very good fliers, they are highly cursorial. That is, they are adapted to running. Most species had rather run than fly. Some can run rather rapidly, while other species are rather slow moving.

Cockroaches continuously expel secretions from their body and regurgitate fluids from their mouth. These fluids are deposited on the surface of objects in the area that they frequent. When this liquid dries, it leaves dark "specks". These specks may be so numerous that large areas on a contaminated surface may appear "blackened".

Cockroaches give off a very offensive odor. Persons that are sensitive to this odor can detect cockroaches by their smell long before they see the pests. This odor is often imparted to food making it unfit to eat. The odor may also linger on dishes for a very long time. Even after washing, the odor may still be detected when dishes are heated.

Most species of cockroaches are highly gregarious. Large numbers are often found crowded into favorable habitats such as behind loose wallpaper, in dark corners, or behind appliances. Many species of cockroaches have become very well adapted to living with man. They will move into your house, eat your food, sleep in your bed and even get in your clothing. The travels of man have spread numerous species, far and wide. They travel with us by air, by land and by sea. They stowaway in our luggage, in our vehicles, our furniture, in various containers and even in our food.

Although most heavy infestations of cockroaches are associated with filth and poor sanitary conditions, infestations know no social barrier. Sooner or later everyone will have at least a few cockroaches in their home.

Cockroaches find their way into our dwellings through faulty doors and windows, through cracks and crevices, down chimneys and through vents. They may enter where we pass wires, pipes and cables through the walls. We also bring cockroaches into our homes as we bring in furniture, clothing or appliances. We bring them in when we bring in firewood, groceries, pet food, cartons and other containers.

Cockroaches prefer warm moist surroundings. Most species prefer to stay on the ground floor or in the basement, rarely going upstairs. They are nocturnal (night active) and are seldom seen in the day unless their numbers are very high. During the day they hide in secretive places such as behind baseboards, between walls, in cabinets and drawers, under and around sinks and lavatories and behind appliances.

Cockroaches are omnivorous and will feed on almost anything. They feed on grease, starchy materials and sweets. Some species have a preference for one type of food over another. They often cause damage to household goods, furniture, and clothing. They will feed on leather, fabric, wallpaper paste, paper and bookbinding.

These pests will also feed on various waste materials, their own cast skins and on live or dead insects.

TELL ME

  1. Even though most cockroaches are very good fliers most are highly cursorial. What does cursorial mean? .
  2. Most species of cockroaches are highly gregarious. What does gregarious mean? .
  3. Cockroaches are nocturnal. What does nocturnal mean? .


MEDICAL IMPORTANCE

It is hard to believe, but in Europe, powdered cockroaches were once sold as a remedy for pleurisy and pericarditis.

It is hard to believe, but cockroaches have never been positively linked to the transmission of pathogenic organisms that infect man. However, the potential for cockroach transmission of certain pathogens, under specific conditions, is undeniable. Cockroaches frequent many sites where they can be contaminated with disease organisms. Afterward, they frequently come in contact with man and this is a potential situation where transmission of these pathogens could occur.

Some areas that cockroaches frequent, where they may pick up pathogenic organisms include human feces and spittle, garbage, sewers, dying and dead animals. Also, cockroaches have been known to crawl on and to nibble at the bodies of helpless infants, incapacitated, ill or sleeping persons and even on human cadavers. Pathogens acquired at these sites could potentially be transmitted to man as they crawl over food, dishes, silverware and other household goods.

Laboratory experiments have shown that cockroaches can harbor thousands of bacteria. About 40 species of pathogenic bacteria, two species of pathogenic fungi, several protozoa, and four strains of poliomyelitis virus have all been isolated from wild-caught cockroaches.

It is a known fact that some people are allergic to cockroaches. Contrary to common belief, it is not the repulsive odor of the pest that people are allergic to. Allergic reactions come from a protein found in the pulverized bodies of dead cockroaches and from their feces.

TELL ME

  1. Laboratory experiments have found about species of pathogenic bacteria on cockroaches.
  2. Name three places that cockroaches may pick up pathogenic organisms. , and .
  3. What is it about cockroaches that people may be allergic to? .


IDENTIFICATION

Of the 4,000 species of cockroaches in the world, the U.S. has about 55 species. This includes 49 native species and about six or seven introduced species. Although a number of species may be found occasionally or accidentally in the home, there are only five species that are considered as common pests in the dwellings of man. These most common species are GERMAN COCKROACH, AMERICAN COCKROACH, ORIENTAL COCHROACH, BROWN-BANDED COCKROACH and the SMOKY-BROWN COCKROACH.

Any attempt to control infestations of cockroaches is greatly enhanced by the positive identification of the species that you are concerned with. Knowing the species enables you to determine the biology, preferred habitat, feeding habits and the proper control technique for the species in question.

Cockroaches are known by several common names. Some of these names are recognized worldwide, some are recognized nation wide; others are recognized in only a small specific geographical location.

Common names may vary from place to place and their use may be confusing. Each species of cockroach has an accepted scientific name, which is composed of its generic and its species name. The scientific names of species will be given here to facilitate further study and to assure that you are studying the species with which you are concerned.

 

German Cockroach

SCIENTIFIC NAME - Blattella germanica

ACCEPTED COMMON NAME - German cockroach

ALIAS - Prussian cockroach, croton bug, water bug

SIZE - 1/2 to 5/8 inch long (10 - 13 mm)

COLOR - The German cockroach is a uniform drab brown. Its legs are a bit lighter in color than its body. The pronotum has two wide, black longitudinal stripes. Between these longitudinal stripes there is a golden brown stripe that extends past the pronotum onto the wings.

DISTINGUISHING CHARACTERISTICS - The pair of black stripes on the pronotum is the most distinguishing characteristic of the species. This with its small size can usually identify the species.

COMMENTS - The German cockroach is native to Europe. It is the most widely distributed and best known species in the U.S.

It is the most pestiferous species in restaurants, grocery stores, multi-unit dwellings and in many homes. This species is most frequently found in kitchens and bathrooms, but under heavy populations it may be abundant anywhere in a dwelling.

It is common to see females of this species carrying an egg capsule at the end of her abdomen.

 

American Cockroach

SCIENTIFIC NAME - Periplaneta americana

ACCEPTED COMMON NAME - American cockroach

ALIAS - palmetto bug, water bug

SIZE - 1 1/2 - 2 inches long (27-45mm)

COLOR - The American cockroach has a uniform light reddish-brown body. Its yellow-brown pronotum has a golden-yellow border. Its legs are also a golden-yellow.

DISTINGUISHING CHARACTERISTICS - The American cockroach has two distinguishing characteristics. One is its size, and the other is the golden-yellow area around the outer edge of the pronotum.

COMMENTS - The American cockroach is world wide (cosmopolitan) in distribution. It is the largest species and the second most common species found in homes in the U.S.

Some authorities believe that this species is a native of tropical or subtropical America. Others believe it to be a native of Africa.

This species is capable of flying long distances but seldom flies at all.

The species thrives in man-made structures. In homes it is most often found in kitchens and bathrooms. It also frequents sewers and steam tunnels.

Females carry their ootheca for one or two days before depositing them.

 

Brown-Banded Cockroach

SCIENTIFIC NAME - Supella longipalpa

ACCEPTED COMMON NAME - Brown-banded cockroach

ALIAS - tropical cockroach, T V roach, furniture cockroach

SIZE - 1/2 inch long (10-14mm)

COLOR - The head and thorax of the brown-banded cockroach is dark brown to almost black. Its wings are also dark brown but banded with light brown. The legs are light brown and have small dark spots at the joints.

DISTINGUISHING CHARACTERISTICS - The most distinguishing characteristic of this species is the presence of a light colored band at the base of the wings and another about 1/4 inch down, toward the tip of the wing. The pronotum of this species is rather small and the head is very prominent.

COMMENTS - The Brown-banded cockroach frequents homes, hotels, apartments and hospitals. It resembles the German cockroach but is smaller in size.

The species is very gregarious. It readily flies when disturbed and often jumps when trying to escape danger. When searching for food, it often stands erect on its legs.

The wings of the male covers its abdomen, but the wings of the female do not.

The light colored bands on their back are more easily detected in the nymphs than in the adults.

 

Oriental Cockroach

SCIENTIFIC NAME - Blatta orientalis

ACCEPTED COMMON NAME - Oriental cockroach

ALIAS - black beetle, shad roach

SIZE - 1-1.25 inches long (18-30mm)

COLOR - The oriental cockroach is dark brown to almost black and rather uniform in color. Its legs are about the same color as their body but can be slightly lighter brown.

DISTINGUISHING CHARACTERISTICS - The oriental cockroach may be distinguished by its large size, robust shape and dark color. The short wings of the male and the rudimentary wings of the female are also distinguishing characters.

COMMENTS - The oriental cockroach is worldwide in distribution. It is normally an outside species, but will move into the home during cold weather. It is commonly found in lawns, along the foundation of buildings, in water meters, in basements and in piles of rubbish.

It is rather slow moving and sluggish, for a cockroach, and neither sex can fly.

 

Smoky-Brown Cockroach

SCIENTIFIC NAME - Periplaneta fuliginosa

ACCEPTED COMMON NAME - Smoky-brown cockroach

ALIAS - black beetle, shad roach

SIZE - 1-1.3 inches long (24-33mm)

COLOR - The smoky-brown cockroach is very uniform dark brown to black in color. If there is any differentiation in color at all, the legs and the pronotum may be slightly darker than the rest of the body.

DISTINGUISHING CHARACTERISTICS - If this species has any characteristic that would help in distinguishing it from other species, it would have to be its large size and the dark uniform color of the pronotum.

COMMENTS - The smoky-brown cockroach is a very close relative of the American cockroach. It is mainly a pest in the eastern and southeastern U.S. This species is common outdoors in compost piles, woodpiles and rubbish. It is more and more becoming a pest of homes, warehouses and other man-made structures.

 

Australian Cockroach

SCIENTIFIC NAME - Periplaneta australasiae

ACCEPTED COMMON NAME - Australian cockroach

ALIAS - black beetle, shad roach

SIZE - 1 inch long (23-29mm)

COLOR - The Australian cockroach closely resembles the American cockroach. It is reddish-brown to dark brown. It has yellow markings on the pronotum and on the front edge of each wing.

DISTINGUISHING CHARACTERISTICS - The Australian cockroach may be distinguished from its near relative, the American cockroach, by the straw-colored to yellowish streak extending about 1/3 of the way down the outer margin of the wings. Also, by the wide yellowish area around the margin of the pronotum which leaves a "double" dark spot in the middle of the pronotum.

COMMENTS - The Australian cockroach is probably not indigenous to Australia. In the U.S., it is found mainly in the southern states.

This species often is found in greenhouses and around structures at zoos.

It feeds mostly on plant material, but in the home it will feed on starchy materials.

 

Brown Cockroach

SCIENTIFIC NAME - Periplaneta brunnea

ACCEPTED COMMON NAME - Brown cockroach

SIZE - 1-1.3 inches long (25-33mm)

COLOR -The brown cockroach is reddish-brown in color and has yellow margins on the pronotum.

DISTINGUISHING CHARACTERISTICS - This species is a bit darker in color than the American cockroach. Also, the wings of the male are not as long as the wings of the male American cockroach. The ootheca of the Brown cockroach is about twice as long as the ootheca of the American cockroach.

COMMENTS - The Brown cockroach is found in the southeastern and the southern states, from Florida to California.

 

Field Cockroach

SCIENTIFIC NAME - Blattella vaga

ACCEPTED COMMON NAME - Field cockroach

ALIAS - vaga cockroach

SIZE - 3/8-5/8 inch long (8.5-11.5mm)

COLOR -The field cockroach is light brown. It has a black face and two black longitudinal stripes on the pronotum. This species has been described as being olive-green in color.

DISTINGUISHING CHARACTERISTICS - The Field cockroach is smaller than its close relative, the German cockroach. The black area on the front of the head is the most distinguishing characteristic.

COMMENTS - The field cockroach is found from Texas to California. It is normally found outside but will occasionally enter homes. It is somewhat active in the day.

 

Asian Cockroach

SCIENTIFIC NAME - Blattella asahinai

COMMENTS - The Asian cockroach is native to Southeast Asia. It is a relative of the German cockroach, but it prefers the outside. The species is now established in Florida and is working its way westward. It is a strong flier and is attracted to lights.

 

Surinam Cockroach

SCIENTIFIC NAME - Blattella surinamensis

SIZE - 0.5-1.0 inch long (16-23mm)

COLOR - This species is shiny brown to black.

DISTINGUISHING CHARACTERISTICS - In this species the wings extend beyond the tip of the abdomen in both sexes. The posterior margin of the pronotun in the adult is sinuate (curved in and out). In some specimens, the anterior margin of the pronotum is marked with a pale band.

COMMENTS - The Surinam cockroach is found worldwide. In the U.S. it is established in Florida, Louisiana and Texas. This species is generally found outside under boards or litter. It is often a pest of greenhouses. In the U.S. the species is parthenogenetic, no males have ever been found.

 

Cuban Cockroach

SCIENTIFIC NAME - Panchlora nivea

SIZE - 0.5-0.75 inch long (12-18mm)

COLOR - The Cuban cockroach is pale green in color. Its head, pronotum and the front half of the front wings are a bit lighter in color.

DISTINGUISHING CHARACTERISTICS - The green color alone is most distinguishing for the species. Most specimens have a small brown spot about 1/3 of the way from the end of their front wings.

COMMENTS - The Cuban cockroach has been known to establish populations in parts of Florida and in Brownsville, Texas.

 

Pennsylvania Wood Cockroach

SCIENTIFIC NAME - Parcoblatta pennsylvanica

SIZE - Female is 0.5-0.75 inch long (12-18mm), male is 1.0-1.25 inches long (22-30mm)

COLOR - This species is very light brown. Its thorax and wing pads are edged with white.

COMENTS - This species is indigenous to the U.S. and ranges from the southeast to the Midwest and into Canada. The males are much larger than the females and have fully developed wings. The wings of the females are very small and are nonfunctional. The males fly readily and are attracted to lights.

 

TELL ME

  1. What are the five cockroaches that cause the most problems in and around the home? , , , and .
  2. The most pestiferous species of cockroach in the U. S. is the .
  3. The largest species of cockroach in the U.S. that is commonly a pest in the home is .
  4. There is one cockroach found in the home that will readily fly when disturbed. This is the .
  5. Give one distinguishing characteristic of the following species of cockroaches.
    German cockroach .
    American cockroach .
    Cuban cockroach .
  6. A large robust cockroach with short wings often found in the yard and in basements is the .
  7. Name two species of cockroaches, normally found in the yard, that can sometimes give problems in the home and .

TEST QUESTIONS FOR CREDIT

   

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