American Cockroach



Cockroaches are insects belonging to the family Blattidae and they share a common ancestry with termites and grasshoppers. Out of more than 3,500 species world-wide, only about 70 species are found in the United States and only one half dozen or so are pests. American cockroaches are one of the most common insect pests found in urban areas throughout the world. This species of cockroach prefers to live in a warm humid atmosphere, the same conditions preferred by man, and so it is no wonder that American cockroaches have adapted to living in buildings, ships, restaurants and greenhouses. Having had a longer track record of survival on the planet earth (300 million years versus 1 million years for man), it is believed by many that cockroaches are likely to out survive man in the long run.


There are several pest species of cockroaches found indoors and many more non-pest species found in nature. The large, reddish brown to uniform brown cockroach, Periplaneta americana, the American cockroach, is the largest pest species of cockroach in the world. American cockroach adults reach 1.5 inches in length and they scoot across the floor with rapid movements. Egg cases (ootheca) containing up to 16 eggs are cemented to surfaces near their food source. The much smaller nymphs or immature stages are rarely seen and they are a darker brown. There are a couple of similar looking species of large cockroaches that are found in greenhouses and in other warm, humid locations so it is import to make a correct identification before starting a control program.


American cockroaches are common in warm and humid areas such as basements, inside sewer lines and in greenhouses. During the warmer summer months, American cockroaches can emerge from landfills and other compost sites and fly. Home owners located near landfills may complain when they see the large adults resting against the siding of their homes.

American cockroaches are poor climbers and are most often found at ground level. They can easily crawl up rough surfaces such as concrete blocks but walls and other smooth surfaces are too difficult. If these cockroaches are found on tables, chairs, or other furniture, they most likely fell onto these surfaces from ceiling voids above. The female does not drop the egg capsule as soon as it is formed, and it may protrude from the body from a few hours up to four days. Egg capsules are often glued to surfaces. The maximum number of eggs per capsule is 16 and the average is closer to 10. This cockroach may molt as many as 13 times before reaching maturity. It may take a little more than a year for a cockroach to reach maturity and then it may live for another year before it expires.

Cockroaches are known mechanical vectors of bacteria and other diseases, their fecal material, hairs and cuticle are the source of allergies and asthma for many, and their odor is described as unpleasant, but their most objectionable characteristic is their tendency to appear uninvited. Long considered a sign of poor sanitation, cockroaches are now identified as a public health issue.


American cockroaches in urban settings are most often found near plumbing fixtures that are not sealed. Therefore finding and repairing plumbing leaks or breaks is often the critical step in long term control. Dried up water traps and floor drains are another very important sources of entry into a building for these cockroaches. Use sticky traps to capture adults and help locate the source of infestation. Check for breaks in discharge sewer lines, where plumbing exits the building wall and even from sewer breaks outside the building where cockroaches then enter through cracks in the building foundation. Older plumbing pipes composed of cast iron may rust along the top of the pipe and even though there are no visible signs of a leak, the cockroaches are able to escape through this break and are unable to return to their original source.

Adults also emerge from sewer lines into buildings from dried up floor drains, broken or uncapped plumbing lines and from pipe chases. Use sticky traps to capture and localize the source of infestation. Consult with a plumbing specialist to find and repair plumbing leaks or other breaks in the plumbing system. After using a shower or after heavy rains, more of these cockroaches may be flushed out of floor drains. A strong odor such as peppermint can be flushed into plumbing vent systems and any leaks in the plumbing system can be detected. An even better method is to place theatrical smoke canisters into vent systems and look for leaking smoke.

By careful monitoring of cockroach population numbers and breeding locations, you can eventually locate and repair the source of the infestation. Baiting may serve to depress local populations but will not provide long term control. Spraying insecticides is even less effective, a dead cockroach is only slightly more acceptable than a live one given their size and ability to appear in public places.


If the sewer break is on the outside of the structure or building it may take even longer to identify and correct. The sewer discharge plumbing line may break near or at the building exterior wall. The cockroaches that escape along with sewage material may eventually find a crack in the foundation wall and enter inside. To control this type of infestation, digging up and repairing sewer lines is required.

The most annoying habit of individual cockroaches appearing throughout a building at random is often due to adult male cockroaches moving a considerable distance away from the sewer break. If you find the smaller nymphs, this is a good sign that you are very close to the source. If you smell sewer gas, you are even closer. Buildings with food discharge from a kitchen facility are able to support larger numbers of cockroaches in the sewer lines. Soda drinks are very acid and tend to eat through cast iron pipes over time. Discharge lines below the kitchen are often a source of American cockroaches when these lines have finally cracked open over time.

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