Insect Identification logo
Icon of the state of Texas
Icon of a spider
Icon of a beetle insect
Icon of a butterfly
Icon of a bee
Icon of the Bugfinder utility

Oriental Cockroach (Blatta orientalis)

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

 Updated: 8/23/2019; Authored By Staff Writer; Content ¬©

An affinity for moisture helps direct the infamous Oriental Cockroach into human habitats.

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 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.
Insect antennae icon
Spiny / Spiky insect icon

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
Prince Edward Is.  
State of Alabama graphic
State of Arizona graphic
State of Arkansas graphic
State of California graphic
State of Colorado graphic
State of Delware graphic
State of Florida graphic
State of Georgia graphic
State of Idaho graphic
State of Illinois graphic
State of Indiana graphic
State of Iowa graphic
State of Kansas graphic
State of Kentucky graphic
State of Louisiana graphic
State of Maine graphic
State of Maryland graphic
State of Michigan graphic
State of Minnesota graphic
State of Mississippi graphic
State of Missouri graphic
State of Montana graphic
State of Nebraska graphic
State of Nevada graphic
State of New England graphic
State of New Jersey graphic
State of New Mexico graphic
State of New York graphic
State of North Carolina graphic
State of North Dakota graphic
State of Ohio graphic
State of Oklahoma graphic
State of Oregon graphic
State of Pennsylvania graphic
State of South Carolina graphic
State of South Dakota graphic
State of Tennessee graphic
State of Texas graphic
State of Utah graphic
State of Virginia graphic
State of Washington graphic
State of West Virginia graphic
State of Wisconsin graphic
State of Wyoming graphic
Canadian territory of Alberta graphic
Canadian territory of British Columbia graphic
Canadian territory of Manitoba graphic
Canadian territory of New Brunswick graphic
Canadian territory of Newfoundland and Labrador graphic
Canadian territory of Ontario graphic
Canadian territory of Quebec graphic
Canadian territory of Saskatchewan graphic
Territory map graphic of the country of Mexico
Contiguous United States shape map layer graphic

Territorial Reach (A-to-Z)
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Rhode Island
South Carolina
South Dakota
West Virginia
Canadian National Flag Graphic
British Columbia
New Brunswick
Newfoundland and Labrador
Nova Scotia
Prince Edward Island
Mexican National Flag Graphic
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.