Oriental cockroach

Blatta orientalis Linnaeus

Class: Insecta
Order: Blattodea
Family: Blattidae

Size: Oriental cockroach adult males are about 1 in (25 mm) long; females are about 1 1/4 in (32 mm) long. Males’ wings cover 75% of abdomen, females’ wings are much smaller.

Color: Usually shiny black, but varies somewhat, and can go to a dark reddish brown.

Where found: In spite of common name, probably from north Africa; also known as a “shad roach”, “black beetle”, or “water bug”; found around the world.

Comparison with other species: Smoky brown cockroach: wings extend to tip of abdomen. American cockroach/Australian and brown cockroaches: wings extend to tip of abdomen, pale markings; American is also larger. Other roaches: smaller or larger, with fully developed wings, not uniformly black, and/or not found in buildings.

Habitat: Outdoors under stones, in leaf litter and other debris; indoors in spaces within walls, crawl spaces, basements, floor drains. This roach may sometimes crawl up along water pipes to the second floor.

Food: Oriental cockroaches feed on all kinds of food, especially starchy ones. They also eat organic matter that is in the process of decaying.

Biology: Female usually deposits her egg capsule within about a day (up to 5) after its formation. It may be dropped onto or glued to a surface that is warm and protected, and near a source of food. She will produce on average about 8 egg capsules (16 eggs each) during her life. Development from egg to adult varies depending on temperature; at room temperature it takes about 20 months. Adults live from about 1 to 6 months.

Damage: Like other roaches, the Oriental cockroach is a nuisance to humans, and feeds on filth. This species also has a strong odor.

Invasion: Oriental cockroaches survive well outdoors in many areas, even after week of freezing weather. They enter around doors, along pipes and air ducts, through drains and unscreened ventilation openings.

How to detect and control Oriental cockroaches:

  • Inspect at night using a flushing agent and flashlight to determine species and location.
  • Check drains.
  • Initial pesticide application may include residual baits, insect growth regulators, liquids, aerosols, lacquers and/or microencapsulated pesticides, placed in cracks and crevices but occasionally on surfaces, or in voids. Dusting of voids is sometimes appropriate.
  • Outdoor barrier treatments with microencapsulated or wettable powders are effective.