Cockroaches are resilient, problematic pests. The Oriental cockroach, Blatta orientalis, is an outdoor species that’s no stranger to venturing indoors for food. These insects are also commonly called “water bugs” and thrive in cool, humid locations.
Unfortunately, Oriental cockroaches are a dangerous, disgusting pest that you definitely don’t want around your home and family. They commonly carry diseases that they pick up from their unpleasant diet of garbage and decaying material. And it only takes a few roaches to spread bacteria all over your home.
The information below will help you to identify an Oriental cockroach problem, eliminate the roaches, and prevent infestations in the future.
Read on to learn about these unwelcome pests. And what you can do to keep them out.
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How to Identify an Oriental Cockroach
Oriental cockroaches have several distinguishing characteristics. They grow to about an inch in length and are dark brown or black in color. They’re smaller than American cockroaches but larger than German cockroaches. Their bodies appear glossy and their legs feature tiny hairs.
Cockroaches have a reputation for being quick, agile insects, but Oriental cockroaches are noticeably slower than other species. Male Oriental cockroaches have wings that cover about 3/4 the length of their bodies, while females have much shorter wings. Despite their wings, neither gender of Oriental cockroach can fly.
Where Do Oriental Cockroaches Live?
Oriental roaches are found around the world and are especially problematic in the Northwest, Midwest and Southern U.S. These cockroaches live primarily outdoors. They will enter homes looking for food but prefer to hide in woodpiles, clutter and debris.
Like many other cockroach species, the Oriental cockroach likes to live in humid places. Cockroaches need easy access to water to survive, so they’re attracted to areas that are humid or wet. However, Oriental cockroaches can live in cooler habitats than those of other roach species. This leads them into sewers, piping and any other damp, cool area in the house.
Oriental cockroaches thrive on a diet high in starch but they’ll scavenge for almost anything edible. This includes trash and sewage, making their presence in or around your home extremely unpleasant.
Places You Might Come into Contact with Oriental Cockroaches
Since these cockroaches look for warm, moist areas to live, you might find them in your garage, basement or crawl space. They also congregate in water meter boxes, around floor drains, and in other damp, shady areas near the ground, particularly those that contain organic debris.
Though they mostly live outdoors, Oriental cockroaches sometimes enter homes through drain pipes or spaces in window frames and vents. Once inside, they can move from room to room on piping in the walls, emerging in bathrooms or kitchens. They can’t climb smooth, steep surfaces, so you might find them trapped in a bathtub or deep sink.2
Signs of an Oriental cockroach infestation include egg cases, dead roaches, and droppings.
If you see a living cockroach, there are probably more hiding somewhere nearby. If the population becomes large enough, you might notice a strange odor near the area they’ve infested. Contaminated food might also give off this odor, signaling that Oriental roaches have touched it.
Life Cycle of Oriental Cockroaches
Female Oriental cockroaches carry egg capsules anywhere between 12 hours to five days before hiding them. The average female produces 8 egg capsules during her lifetime, called oothecae, that contain as many as 16 eggs each. The egg cases are a little less than 1/2 inch long and dark red or brown.
Populations can increase rapidly–a single female cockroach typically lays enough eggs to produce 115 roaches in a year. After hatching, the nymphs (baby cockroaches) mature slowly for cockroaches (around 185 days for males and 216 days for females), with 89% surviving to adulthood.
Adult Oriental cockroaches typically live between 1 to 6 months, mating at any time during that period. However, Oriental cockroach populations are seasonal, usually peaking in the spring and early summer. The largest number of nymphs tend to hatch later in the year.
These cockroaches depend on accessible water for survival but they can live up to a month without eating.
Are Oriental Cockroaches Dangerous?
Oriental cockroaches are problematic pests to find in your home. Their diet of garbage, sewage, and decaying matter makes them prime carriers of bacteria.
Once cockroaches have found a way into your home, they can quickly contaminate cooking surfaces and any food that’s left unsealed. They feed on crumbs, spills, and tiny scraps of food, and sometimes hide their eggs in unsealed food or pantry products.
In the process, they can contaminate utensils, cooking supplies, countertops, bathroom supplies and other household items. Floor drains and under-sink spaces are particularly attractive to cockroaches, as they frequently contain food waste.
Some of the most common illnesses that result from Oriental cockroach infestations are food poisoning and diarrhea from the Salmonella and E. coli they can carry and transmit. Dead roaches, old egg cases and droppings can also trigger allergic reactions and asthma attacks in people sensitive to allergens.
How to Get Rid of Oriental Cockroaches
Controlling an Oriental cockroach infestation begins with discovering how they made their way in. It’s important to carefully inspect your home, inside and outside, to find their entry points. Look for gaps in siding, cracks leading into your basement, spaces where pipes enter the walls, and any other holes near the ground.
Oriental cockroaches are most active at night, so it’s difficult to spot them in action. You’ll do better looking for signs (such as droppings), and noting areas they’re likely to gather (for example, holes in walls and cracks along the floor).
Sometimes, it’s necessary to place sticky traps in areas you suspect cockroaches are hiding to better pinpoint their habitats. Insect “bombs” or foggers are not usually effective because Oriental cockroaches tend to hide in crevices and holes that are difficult to reach.
Professional treatment might be the only option for a large infestation. Professional pest controllers might use a perimeter spray to deter them from your house.
Tips for Preventing Future Cockroach Infestations
Oriental cockroaches are resilient pests that are dangerous to your home and can be difficult to control on your own. It’s much easier to take measures to prevent an infestation than it is to control one.
Here are some tips to help you protect your home from Oriental cockroaches:
- Prevent clutter in storage areas
- Seal holes and cracks around your home
- Clean up landscaping, stack woodpiles, and clear leaves and debris around windows and doors
- Sweep for crumbs and wipe counters frequently
1. Prevent clutter in storage areas
Oriental cockroaches’ favorite locations are cluttered, humid, dark spaces. Unfortunately, basements and crawl spaces are often exactly that: poorly ventilated and full of boxes and clutter. This makes them ideal habitats for cockroaches and other insects.
Tidy up these and other storage areas–your garage or shed, for example–to make them less attractive to pests. If you live in a particularly humid environment, it might be necessary to repair or install better ventilation.
2. Seal holes and cracks around your home
Over time, holes and crevices develop around the outside of your home. Weathering can create spaces around piping and utility boxes, making it easy for pests to come inside. Taking time to properly seal the exterior and interior walls of your home can make a big difference in your fight against pests. Use caulking in and around high-risk areas, such as closets, cabinets, doors, windows, and walls, to prevent cockroaches entering.
3. Clean up landscaping and woodpiles
As primarily outdoor creatures that tend to gather in warm, moist, shady areas that provide them food, hydration and protection, your goal is to deprive Oriental roaches of the spaces and material they find attractive around your home.
If the plants around your home have become overgrown or cluttered, spend some time clearing out the debris to remove potential cockroach habitats. In addition, you should stack woodpiles neatly (and away from your home, if possible) to keep them dry and organized.
4. Sweep for crumbs and wipe counters frequently
The primary reason an Oriental cockroach (or just about any other pest) enters your home is to find food. Leaving dirty dishes in the sink or crumbs on the carpet makes it easy for insects to thrive on your leftovers. To prevent dangerous pests from making your home their home, turn cleaning into a nightly habit.
Always sweep and vacuum floors for crumbs. Clean dishes after you’ve used them and wipe counters every night. We know that nobody wants more chores, but you’ll thank yourself every day that you don’t find roaches or other bugs scurrying across your floor.
You can’t cut corners when it comes to defending your home against pests. Oriental cockroaches are an especially resilient and dangerous pest. It’s important to do everything you can to keep them out.
If you’ve already seen a cockroach or found evidence that they might be present, don’t take any risks. Start planning your cockroach control solution today.
If you’re worried you won’t be able to stop them on your own, call a professional pest control service. Cockroaches can spread disease and multiply quickly. Implementing effective pest control as quickly as possible is key to eliminating the problem.
You can do this! Take action today to live pest-free tomorrow.
Frequently Asked Questions
No. Oriental roaches have wings, but their wings are too small and underdeveloped to be used for flight.
No. Unlike many other roaches, their legs aren’t equipped for climbing.
Oriental cockroaches have the ability to bite humans, but rarely do.
It does happen, but usually only under certain circumstances: Your toilet has a u-bend that creates a water barrier between the sewer and your home. Should the toilet and u-bend dry out, roaches have an unobstructed path from the sewer into your house.
No. Oriental cockroaches do not jump, and don’t even move very fast. Their legs are made for crawling.
Oriental roaches don’t swim, but they do float. They can also remain totally submerged in water for as long as 40 minutes.
You can try, but it may not be very helpful. Since a cockroach can live for 40 minutes submerged, there’s a good chance it will end up alive in a nearby sewer – and possibly return to your house.
Yes. Groups of Oriental cockroaches give off a pungent, unpleasant odor.
Oriental roaches can be killed with special dusts, baits, and sprays. The dusts are applied to areas where they travel. Sprays kill them on contact. And baits kill them after they’ve found and eaten them.
Begin by eliminating their access to food, water, and shelter – by cleaning up food sources, eliminating water drips, and plugging or patching holes around your house. To kill them, boric acid is a natural product that is often used to good effect.
Oriental cockroaches are one of the more difficult roaches to eliminate, but the answer is yes – an exterminator can get rid of Oriental cockroaches.
Written by Andrew Martin. Reviewed by Rae Osborn, PhD.
Andrew writes for, and along with his daughter, publishes Cockroach Facts. You can read more about him here.
Rae Osborn, PhD.
Dr. Rae Osborn holds Honors Bachelor of Science degrees in Zoology and Entomology, and a Master of Science in Entomology from the University of Natal in South Africa. She holds a PhD in Quantitative Biology from the University of Texas at Arlington, where her research was in Entomology. You can learn more about our contributors here.
- McCanless, Kim (2014) Oriental Cockroach. Featured Creatures. Retrieved from http://entnemdept.ufl.edu/creatures/urban/roaches/oriental_cockroach.htm
- Sutherland, Andrew M. (2019) Pests of Homes, Structures, People, and Pets. How to Manage Pests. Retrieved from http://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html
- Jacobs, Steve (2017) Oriental Cockroaches. PennState Extension. Retrieved from https://extension.psu.edu/oriental-cockroaches