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Oriental Cockroach (Blatta orientalis)


Detailing the physical features, habits, territorial reach and other identifying qualities of the Oriental Cockroach.

 Updated: 11/30/2018; Authored By Staff Writer; Content ¬©www.InsectIdentification.org




An affinity for moisture helps direct the infamous Oriental Cockroach into many unwanted areas.



Found in all three countries of North America, the Oriental Cockroach is not originally from the continent. Despite the common name, it may not even originally come from Asia either. Regardless of its origin, it has established itself as one of a handful of pest cockroach species. Its ordinary habitat is woodland leaf litter and other moist areas, but its innate attraction to water and moisture has led the species to more developed areas. Because of its affinity for wet terrain, it is also called a Waterbug. Populations of Oriental Cockroaches commonly infiltrate sewer systems and pipelines, crawling on pipes and entering homes, offices and other buildings through small openings, like those around pipes. They seek shelter in crawlspaces, cellars, and basements where high humidity is often normal. Once inside, they explore for food sources and sometimes hide in sink (kitchen and bathroom) and tub drain holes. Their sudden emergence from drains terrifies the best of us. They tolerate dry areas well enough to also hide under furniture, behind radiators, and in dark closets. This adaptability makes them a serious nuisance indoors. This is also the type of cockroach seen scurrying out from under outside containers, like garbage cans.

The average lifespan of an Oriental Cockroach is about 18 months. They mature the first year, molting many times until they become winged adults. Long-winged males and the short-winged females cannot actually fly though. After mating, dark, tubular egg sacs the size of Tic-Tacs called ootheca are wedged in cracks, crevices, and other hiding places to increase the chances of offspring survival. Each brown capsule can carry over a dozen tiny eggs. Both nymphs and adults feed on pretty much anything, even filth and sewage, but they are especially fond of starchy items like crumbs, cereal, cookies, and most foods stored in pantries or cupboards.

Infestations are difficult to control and may require multiple treatments, possibly from a professional. Finding and destroying egg capsules in tiny cracks is hard, even with spray insecticide, so it is reasonable to think complete eradication from a home or building may require months of applications to reduce the living adult population and then the younger, newly born nymphs. There are some things one can do to make it harder for Oriental Cockroaches to enter a building in the first place: seal gaps in door and window trim, as well as gaps around any incoming pipes. Use an appropriate insecticide to spray around the exterior and interior of the building. Fix water leaks, even small ones, to help keep areas dry and less attractive.

Chances are, however, if you are reading this, they have already found a way in. If they have infiltrated the premises, still consider making it harder for more to come in by plugging exterior gaps. Cockroach bait (i.e. 'roach motels') can poison adults and nymphs. Insecticidal sprays created just for cockroaches can help reduce their presence in sprayed areas. The destruction of ootheca is necessary to prevent reoccurring population booms, so look for and destroy any dark brown capsules hiding in corners, cracks in the floor or walls, and even in drains. Drain caps will prevent hiding adults or hatching nymphs from scaring people when water is turned on. Fortunately, this species of cockroach is a slow mover compared to others. This may be a small comfort in the event of an infestation, but it also means slippers and shoes are useful tools for reducing the population. If the situation seems beyond control, call in the professionals.




Taxonomic Hierarchy
Kingdom: Animalia
  Phylum: Arthropoda
    Class: Insecta
      Order: Blattodea
        Family: Blattidae
          Genus: Blatta
            Species: orientalis
Identifying Information
Scientific Name: Blatta orientalis
Other Name(s): Waterbug, Black Beetle
Category: Cockroach
Size (Adult; Length): 18mm to 30mm (0.70in to 1.17in)
Colorwheel Graphic Colors: brown, black
Descriptors: wet, slow, antennae, spiky legs, roach
Territorial Map
Alaska  
Hawaii  
Prince Edward Is.  
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Territorial Reach (A-to-Z)
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
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Alberta
British Columbia
Manitoba
New Brunswick
Newfoundland and Labrador
Nova Scotia
Ontario
Prince Edward Island
Quebec
Saskatchewan
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Mexico
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.