There are four primary kinds of cockroaches that can infest homes in the Northeast, including German cockroach, brownbanded cockroach, American cockroach, and Oriental cockroach. These four species can be major pests in restaurants, hospitals, warehouses, offices and buildings with food-handling areas. A fifth kind, the Pennsylvania wood cockroach, may enter buildings accidentally but become only a temporary nuisance.

Figure 1. German Cockroach. (University of Nebraska, Department of Entomology)

Figure 2. Brownbanded Cockroach (University of Nebraska, Department of Entomology)

Figure 3. Oriental Cockroach (University of Nebraska, Department of Entomology)

Figure 4. American Cockroach (University of Nebraska, Department of Entomology)

Figure 5. Pennsylvania Wood Cockroach (University of Nebraska, Department of Entomology)

Figure 6. Australian Cockroach (University of Florida Entomology and Nematology Dept)

Figure 7. Cockroach Egg Cases (University of Nebraska, Department of Entomology)

Figure 8. Sticky roach trap under kitchen sink

Identification

Correct identification of suspected cockroaches is important as there are many insects that look similar (e.g. long-horned beetles, crickets, leaf-footed bugs and ground beetles). A cockroach has a flattened, oval shaped body and long antennae (about the length of their body). When looking at a cockroach from above, its head is hidden from view. It has six strong legs covered with spines (figs.1, 2, 3, 4, 5, 6).

Many adult cockroaches have fully developed wings, although few fly. Other roaches have short wings or lack wings altogether. Young, immature cockroaches resemble adults but are smaller and wingless. If there is any doubt about whether an insect is a cockroach, submit a sample to a pest management expert from Pestech.

Biology

A cockroach has three stages during its life cycle: egg, nymph, and adult. Adults lay eggs contained within egg cases that are dark-colored and roughly the same size and shape as a dry kidney bean (fig. 7). Depending on the species, an egg case contains between 16 - 50 eggs. Eggs hatch into young cockroaches called nymphs. In a normal cockroach population, nymphs are more numerous than adults.

Cockroaches are nocturnal, hiding during the day and becoming active at night. The number of cockroaches people see is usually a small percentage of a much larger population. Cockroaches prefer different habitats depending on the species. German cockroaches prefer dark, warm, humid areas near sources of food and water. American and Oriental cockroaches prefer coolers areas, such as basements and crawl spaces. Brownbanded cockroaches prefer drier areas, such as pantries and closets. All roaches are scavengers and will survive on almost any food as well as backing glue, leather, bookbindings, bar soap. They may even sample electronics and wiring in television and microwave (though infestation have to be large when this type of damage occurs). They spend most of their time in narrow, tight cracks and spaces where surfaces touch them on both sides. Cockroaches tend to congregate in corners and generally travel along the edges of walls or other surfaces.

Types of Cockroaches

The German cockroach is the most common indoor cockroach species in the Northeast. It favors warm, humid atmospheres, especially areas where temperatures are around 70° to 75° F. It generally inhabits kitchens and bathrooms where they are found near plumbing fixtures, in cracks or crevices in cupboards, under drawers and kitchen sinks, and similar locations. These cockroaches often cluster together in favorable hiding areas. When severe infestations occur, they may be found in other sections of buildings. German cockroaches can disperse in large numbers from areas of high population densities to infest other locations.

The adult (fig. 1) is about ½ inch long, light brown or tan, and has two dark longitudinal bands or streaks on the prothorax behind the head. This species has the highest reproductive potential of all the common pest cockroaches. Females produce about 30 to 50 eggs at a time. The female carries the egg case until the eggs are ready to hatch.

The immature nymph (fig. 1) is smaller, dark-colored with a light-colored streak running down its back. An immature nymph reaches maturity in about 40 to 125 days. Adult females live about 200 days, producing six to eight egg cases throughout their life.

The brownbanded cockroach may also be common in Northeastern homes. Individuals can be widely distributed throughout a building, particularly in high areas, hiding behind pictures and clocks, beneath furniture, among books and in other drier areas not normally infested by German cockroaches. They seek areas that are warm most of the time including appliances such as radios, televisions and refrigerators. The brownbanded cockroach prefers warmer temperatures (greater than 80° F) than the German cockroach. The two species are rarely found together.

The adult brownbanded cockroach is about ½ inch long. An adult male is golden brown and has a narrow body with its wings extending beyond the tip of its abdomen (fig. 2). A female adult is dark chestnut brown, has a teardrop-shaped body, and its wings do not completely cover the abdomen (fig. 2). Both sexes have distinctive horizontal yellow bands. The female often glues its egg case on furniture or in appliances. Eggs take about 70 days to hatch and about 160 days for the young to reach maturity. A nymph is recognized from the two pale bands which run horizontally across its body.

The Oriental cockroach prefers dark, damp places. Often called a water bug, it is commonly found in damp basements, cellars, crawl spaces, and sewers. It may also be found near drains, leaky water pipes and under refrigerators, sinks, washing machines, and floors. It prefers temperatures under 84° F. The Oriental cockroach can tolerate cool environments and people have even found it surviving freezing outdoor weather. An Oriental cockroach forages mostly on the first floors of buildings. Occasionally, this pest will thrive in the landscape immediately adjacent to structures and may enter if a disturbance occurs, such as a change in the seasons, excess rainfall, or lawn mowing. It can be found occasionally outdoors under sewer covers. It feeds on all types of garbage and other organic material. An Oriental cockroach produces a strong smell and is considered one of the dirtiest of all the cockroaches.

An adult Oriental cockroach is about 1 to 1-1/4 inches long and dark brown, almost black. A male has fully developed wings which are shorter than the body. A female has very short, rudimentary wings (fig. 3). A nymph is similar in appearance to a female only it is smaller and wingless. A female deposits an average of eight egg cases during its lifetime; each capsule produces about 16 young. It takes 300 to 800 days, depending on conditions, for Oriental cockroaches to hatch from eggs and develop into adults.

The American cockroach is occasionally found in homes, although it is more common in restaurants, grocery stores, and bakeries and other sites where food is prepared. It favors very warm, moist places (temperatures in excess of 82° F). An American cockroach has a fondness for fermenting foods, e.g. bread soaked with beer. Their foraging is confined mostly to the basement and ground floor of a building unless suitable conditions exist in higher locations. Sewers and drain lines may help this pest invade new areas.

This is the largest cockroach species to infest buildings in the Northeast. Both the adult male and female is about 1-1/2 to 2 inches long, reddish brown and possesses long wings that cover its abdomen (fig. 4). A female typically produces 9 to 10 egg cases which are deposited carefully in a crack or crevice. Eggs hatch in about 45 days with each case producing about 14 young. An immature nymph is reddish brown and wingless. A young nymph matures in as little as 215 days to as long as 400 days. The average life span for adult females is about 440 days.

The Pennsylvania wood cockroach lives in wooded areas in rotting logs and under loose bark. It can accidentally invade homes, cabins, cottages, and other buildings in or near wooded areas. This cockroach is not a persistent household pest and it doesn’t reproduce indoors. Because of its association with wood, a Pennsylvania wood cockroach can be brought indoors on firewood. It may enter buildings if suitable harborage (trees and logs) is close to open doors and windows. The males are strong fliers.

The adult male is one inch long, dark brown, with light-colored bands on the edge of the body near the head (fig. 5). Males also have long, well-developed wings. The adult female is similar, but with very short wings (fig. 5), measuring about 1/2 inch long. Adult females and immature nymphs can be confused with the Oriental cockroach. However, the Oriental cockroach lacks the light bands on the edge of its body near the head. If there is any doubt, submit a sample to a pest management expert from Pestech for identification.

Exerpt from:

Jeffrey Hahn is an Extension entomologist
Mark Ascerno is an Extension entomologist and department head
Department of Entomology
College of Agricultural, Food and Environmental Sciences