How to Get Rid of Oriental Cockroaches

Identifying & Eliminating Oriental Roach & Black Cockroaches in Your Home

Oriental Roaches (Blatta orientalis) are commonly called "water bugs" or "black cockroaches." They live in damp locations such as basements and around floor drains; they are associated with water. Outside, they live near foundations, crawlspaces, yards, and retaining walls. They feed on filth and decaying matter

Oriental Roach Identification

  • The Oriental cockroach is shiny black and is about 1.25 inches long.
  • They have wings, but the male or female roach can not fly. The total length for the female is 1 ¼" and 1" for the male. The females have small nonfunctional wings while the males have wings that cover about ¾ of the abdomen, neither the female nor male can fly. Adults are very dark brown or black.
American, Oriental, German and Brown-Banded Roaches
Cockroaches (left to right): American, Oriental, German and Brown-Banded
(Photo by Jim Kalisch, UNL Dept. of Entomology)

How To Get Rid of Oriental Roaches

Oriental Roach
Oriental Roach

How Oriental Roaches Enter Your Home

These cockroaches frequently live in floor drains that drain directly outside; they use these drains are also used as entrances to homes. Oriental roaches may enter your house in search of food. During times of drought, there may be a movement towards the inside of the home, but generally speaking, they are found outdoors during the warmer months. They may also move inside if it is unseasonably cold. Oriental roaches often move inside in large numbers, a residual perimeter treatment is recommended for control.

We recommend that you practice good exclusion habits.

Pest Control Products To Use For Oriental Cockroaches

Outdoor Building Treatment and Points of Entry

Insecticide Sprays:

Generally speaking, control measures should concentrate on the outside of the building and points of entry. This control measure is called a "perimeter or barrier" treatment.

You may use concentrated residual sprays: Avesta CS, Cyper WSP, or Demon WP inside or outside. Spray a 3-6 foot band around the entire house. Spray outside around doors, windows, pipe openings, and dryer vents.

Recommended products are in the table below. They would require pump sprayers.

Where To Spray:

  • You may use three residual sprays: Avesta CS, Cyper WSP, or Demon WP inside or outside. Avesta CS will dry without a visible residue on sprayed surfaces. Cyper WSP and Demon WP will leave a visible powdery residue against surfaces.
  • Spray outside around doors, windows, pipe openings, and dryer vents. Apply also on the inside on the baseboards near the entry pts.
  • Apply these insecticides on the inside, applying around the plumbing under the sinks and washer and dryer connections.
  • You don't have to spray all the interior baseboards, just the corners, and baseboards inside the garage and basement areas.

Additional Treatments

Insecticide Granulars: You may apply granular around the base of the house, particularly in areas of pine straw and mulched areas. Bifen Lp is the recommended insecticide granular.

Granular Insect Baits:

Insects baits like Invict Xpress Granular Bait or Intice Perimeter Bait can be used indoors, outdoors, or in turf areas. Invict Xpress has multiple food attractants to attract not only the Australian Roach but also Crickets, some Ants, Silverfish, Earwigs, and Firebrats.

Application:

You may apply Bifen LP Granules around the base of the house, particularly in pine straw and mulched areas, and or Intice Perimeter Bait as supplemental treatments. If you have these larger cockroaches entering inside your home from the attic area (due to trees that overhang the attic or gutters that are not clean) using baits like Intice insect baits, will give you excellent results.

Key Takeaway

Because Oriental Roaches can be found both indoors and out thorough treatment of structure on the inside and on the exterior perimeter is recommended.

Insecticide Granules and Insecticide Baits

Retreatment

The residual insecticides: Avesta CS Cyper WSP, and Demon WP as well as the residual granular, Bifen LP Granules should be repeated every three months during the season. The top recommendation is Avesta CS. It has an improved encapsulated formula to cause it to bond to surfaces better and holds up under ultraviolet light and rain longer.

The Invict Xpress Granular, Intice Perimter last about 6 months, free from rain. D-Fense Dust lasts from 6 months to a year, if free from rain.

Oriental Cockroach Diet

The Oriental roach eats decayed organic matter in mulch piles and rubbish. This cockroach prefers starchy food and builds up populations around garbage cans. Most of their water sources come through their food and the moisture around them.

Diseases Oriental Roaches Carry

Since Oriental roaches will eat decayed matter and live in unsanitary conditions, they can carry bacteria over your countertops, plates, and utensils. They can spread e. Coli, salmonella, dysentery, and cause food poisoning.

Biology of Oriental Roaches

Oriental Roach Development
Oriental Roach Development

Females produce an average of 8 egg Capsules, containing 16 eggs in each, from spring to mid-summer. Unlike other urban cockroaches, the Oriental roach produces only one generation per year, where temperatures are cool. The female will carry the egg capsule(irregularly shaped, black,3/8" long, and 1/4"wide), for around 30 hours and then drops or attaches it in a protected area, near a food supply. The eggs hatch in about 60 days under warm conditions. At least 75% of the eggs must hatch to open the capsule.

The young become adults in 6-12 months. Nymphs(young) are active from about March through much of the summer. During this period, they molt seven to ten times and are reddish-brown to black, except in the first stage, when they are pale tan.

The older brown Oriental cockroach nymphs are very difficult to distinguish from the American cockroach nymphs. This type of roach will have a seasonal cycle in its development. Oriental roaches peak to adults during the spring and early summer, dwindling in numbers by the late summer/early fall.

Nymphs(young) are active from about March through much of the summer. You only find adult Oriental roaches in early spring. By late spring, nymphs are abundant. As nymphal numbers increase, the adults die off, and by August, any adults are new ones. By fall, almost the entire population consists of adults.

Top picture by Daniel R. Suiter, Univ. Of Ga.

Prevent Oriental Cockroaches

  • Caulk all penetrations through ground level walls.

  • Stop water leaks, screen equipment overflow drains, and take overflow water away from buildings; keep drain traps full or capped.

  • Remove rotting leaves from window wells.

  • Move garbage cans out of preferred moist habitat.

  • Ventilate moist spaces.

 

 

Various Roaches That Invade Homes and Businesses

( American and German Roaches are the most common and have two different types of treatments.)

Small Roaches (German and Brown-Banded) 1/2"-1 " in the adult stage
Large Roaches (American, Australian, Oriental, Smokey Brown and Wood ) 1.5 " or longer in the adult stage
Recommended residual sprays for perimeter treatments and basements

Written by our resident pest control expert Ken Martin.