The name “Dusky Cockroach” is used to describe more than one species of insect. The insects that people refer to as “dusky cockroaches” are also called by other names as well.
In the United Kingdom, the name Dusky Cockroach is used to describe Ectobius iapponicus (L.). This is a small cockroach that is native to the U.K. Females are about 1/3″ long and males are slightly larger. They are dark grayish-brown. The males have a dark brown shield over their head. The females have dark brown abdomens.
These are outdoor roaches that live in grassland and woodland. They occasionally invade homes and businesses. Some scientists refer to this roach as the Tawny cockroach, although there is another species that also goes by that name. That roach is E. pallidus.
Among other people, the name Dusky Cockroach is sometimes used for Periplaneta fuliginosa (Serville). It is also sometimes called Duskybrown cockroach. In the United States, it is commonly called the smokeybrown cockroach.
This is a large cockroach. Adults can reach almost 10.5″ in length. It is shiny, dark brown in color. It is attracted to light and it flies well. Because of this, it often enters homes through gaps in the eaves and through attic vents.
This cockroach has been transported from the United States by cargo containers and airplanes. The smokeybrown roach is now found in Japan, Korea, and Southeast Asia. Outdoors it feeds on plants and decaying leaves. When it has moved indoors, it will feed on anything that is available.
Cockroaches that normally live outdoors and invade occasionally are often called peridomestic. They are easiest to control when they are still outdoors.
Remove cockroach habitats like woodpiles away from the house and stack them on racks. Remove attractants, like leftover pet food on the patio. Pick up any un-eaten food after the pet has finished eating. Keep the trash can securely closed.
Check exterior doors to be sure they close securely. Check at night to see if light shines under the door to attract roaches or other insects. Check the screens on crawl space and attic vents. Make sure the crawl space access door is secure.
Many brands of granular roach bait are water-resistant. This makes them effective against smokeybrown roaches in flowerbeds and ground cover. A barrier of liquid insecticide can be applied to the outside foundation to keep roaches from gathering near the house. Because of sun and rain, the insecticide will have to be re-applied periodically. Many people find it convenient to have a pest control professional make these applications.