Oriental Cockroaches


Oriental cockroach adults are about one-inch long and are dark brown or a glossy jet black in color. The males of this species have wings that cover about ¾ of its body, while the females have a small wing pad. The immature nymphs look much like smaller versions of the adults


Oriental cockroaches are active both indoors as well as outside, but often move inside homes or other buildings when the temperature begins to drop in the late fall and winter months. When these roaches move inside, they are most likely to take up residence in basements, crawl spaces, and areas that are close to food and moisture. Oriental cockroaches love to move through sewer lines and often get inside by crawling through sewers and drainpipes. Should a homeowner find a large number of Oriental cockroaches suddenly showing up inside, check to see if there is a plumbing leak, which may be causing cockroaches to congregate and feed on the leaking fluids and small pieces of food debris.

Outdoors, Oriental cockroach populations are more or less seasonal, with adults most likely to be seen during the spring and summer months. Outside, they look for much the same type of living conditions as inside – cool, damp, protected, and close to food. Outside, such areas may include around garbage cans or dumpsters, under piles of debris, and voids that occur around the home’s foundation and the ground. In the late summer when it gets particularly dry outside, Oriental cockroaches may also move from place to place in hopes of locating an area with higher humidity.


Oriental cockroaches are likely to eat anything that is moist and has a high organic matter content. Some of their more preferred foods include garbage, sewage, and foodstuffs that are high in starch.


Their preferred habitats are very general in nature, but will always include locations that are dark, high in humidity, moist, cool, and close to a food source. Examples of indoor habitats can include a home’s crawl space, basement, in-floor drains, under the kitchen sink, and in the bathroom.


Oriental cockroaches go through incomplete metamorphosis – meaning they develop in three distinct stages – egg, nymph and adult. Female cockroach eggs are housed in an egg case that contains around 16 individual eggs. The female will carry the egg capsule in her abdomen and deposit the capsule in a place that is warm, close to a food source, and provides shelter and protection for the eggs. The time period to complete the Oriental cockroach life cycle depends upon the quality of their environment, but averages about ¾ of a year to go from the egg to adult stage.


Like most other insects, the obvious indication of activity is sighting the presence of either Oriental cockroach egg cases, nymphs, or adults. Other signs of their activity include cockroach cadavers, body parts, and evidence of fecal smears. Where populations are very large, odors from the cockroach’s bodily secretions are such that the population can be smelled.


Prevention associated with Oriental cockroaches includes:

  • Sealing cracks, gaps, crevices, and holes to keep cockroaches from getting inside.
  • Covering floor drains with a mesh screen that will keep them from crawling inside through sewer pipes or floor drains.
  • Repairing plumbing leaks.
  • Installing dehumidifiers and other sources of ventilation in basements or crawl spaces.
  • Removing leaves or other organic matter from around the outside of the building.
  • Keeping garbage cans and the area around garbage receptacles clean and dry.


Controlling Oriental cockroaches must always be done by carefully and completely following the product label’s directions. Some products for control can include:

  • Applying a liquid insecticide around the exterior perimeter, around doors and openings into the structure for electrical or plumbing lines, and inside cracks and crevices where cockroaches are seen or may be hiding.
  • Using sticky traps or vacuums to mechanically catch and remove cockroaches
  • Using bait formulations to kill cockroaches in both exterior and interior locations.