Pest Profile: Oriental Cockroach
Scientific Name: Blatta orientalis Linnaeus
- Male Oriental cockroaches are 1-inch long when mature; females are 1-1/4-inches long
- During her lifetime the female Oriental cockroach produces an average of eight egg capsules, each of which contains 16 eggs
- Can become very abundant in damp secluded places such as crawlspaces, basements, water meter boxes and drains
- Prefer to feed on starchy foods but will eat various other items including decaying organic matter
- Produce a very characteristic pungent “cockroach” odor
Male Oriental cockroaches are 1-inch long and females are 1-1/4-inches long when mature. Their coloring is red-brown to black. In males, the wings cover 75 percent of the abdomen; in females, they are reduced to small wing pads. Early nymphs are light brown but become increasingly darker with each molt. The purse-shaped egg capsule (i.e. ootheca) is dark red-brown but becomes black with age, is 3/8-inch long, and typically has eight eggs per side.
During her lifetime the female Oriental cockroach produces an average of eight egg capsules, each containing 16 eggs. The capsules are dropped or, using secretions from her mouth, glued in protected locations such as cracks and crevices near food sources. The nymphs molt about 10 times before becoming adults. Depending on temperature, this requires 206 to 800 days. Adult females live from 34 to 181 days and males from 112 to 160 days.
Oriental cockroaches are not common pests in most homes. They can be abundant, however, in sewers and commercial facilities such as groceries, restaurants, hospitals, and office and apartment buildings. Indoors they can become very abundant in damp, secluded places such as crawlspaces, basements, water meter boxes and drains. They often are found in bathtubs and sinks because they lack the small pads on their tarsi (i.e. last segments of the legs) commonly found on other cockroaches, which allow them to crawl up smooth surfaces. Outdoors, even in cold weather, they are found in planters, ground covers, stones, leaf litter and other debris.
Many types of sticky traps are available to help monitor and pinpoint sources of infestation. Visual inspections can be conducted with a flashlight and aerosol pyrethrin to flush cockroaches from harborages. An effective management program depends on good sanitation. It is critical to reduce clutter, as large cockroaches like to hide in stacked boxes, rolled carpeting, and stored paper materials, especially in dark, damp locations. Vacuums can be used to remove cockroaches. Permanent reduction can be achieved by caulking to eliminate harborage and prevent entry. It is most important to eliminate cracks at which sinks and fixtures are mounted to walls and floors, around plumbing, and cracks on or near food preparation surfaces. Basement floor drains should be protected with screens or inserts which should be cleaned regularly.