American Cockroaches: What You Should Know About These Large Pests

Written by: A O’Neill, Licensed Pest Management Professional

The American cockroach (Periplaneta americana) is a peridomestic pest and is the largest of the common household roaches that cause infestations. It’s also known as a ‘water bug’ or ‘palmetto bug’.

Although not native to North America, this species is also found in other countries, such as Canada, the United Kingdom, Europe, and Australia, in addition to the United States.

What Do American Cockroaches Look Like?

What does an American cockroach look like
Close up photo showing what an American roach looks like
  • A reddish-brown color characterizes the adults
  • Fully developed wings cover their entire abdomens and they can fly.
  • A distinctive feature of the American roach is the yellow-colored band around the edge of the shield-shaped region behind its head, called the pronotum. 
  • Adult American cockroaches are around 1.5 inches (3.8cm) long but these big roaches can grow to over 2-inches (5cm).
  • They have oval bodies with two long antennae and six legs that have spines on them.

What Do American Cockroach Nymphs Look Like?

  • American roach babies are around 1/4 inch (0.25 cm) long when born and are a gray-brown color.
  • Their color changes to reddish-brown as they molt and grow into adults.
  • The yellow-colored band on the pronotum becomes more noticeable as they grow.
  • Immature American roaches cannot fly or reproduce.

American Roach Life Cycle

Picture of American roach nymphs and adults
Picture of American roach nymphs and adults. Image: Daniel R. Suiter, University of Georgia, Bugwood.org

Female American cockroaches produce a purse-shaped capsule (ootheca) around a week after mating.  The egg case will typically have between 14 and 16 eggs inside, with seven to eight eggs on either side.[1] 

In this species, the ootheca is a dark red-brown color and is approximately 3/8-inch (0.9cm) long, and is hidden away in cracks and crevices close to food sources.  The female often uses her saliva to glue them into these spaces.

Approximately 600 days pass between the egg and adult stages, and in that time the immature roaches molt, or shed, their exoskeleton up to 13 times before they become adults and are able to mate and reproduce.  

How Long Do Adult American Cockroaches Live For?

Aside from the 600 days, it takes to become adults, female American cockroaches can live for more than a year – about 440 days, whereas the male has a much shorter adult lifespan and lives only about 200 days.

How Many Eggs Do American Cockroaches Lay?

An adult female may produce around 10 egg cases during her lifetime, so that means around 160 nymphs are born overall. Nevertheless, temperature, humidity, and other environmental factors can affect their development and reproductive times.

Can American Cockroaches infest your home?

Yes, American roaches can and do infest homes.  Although they prefer to live outdoors in the warmer months. This species can also be found in sewers and drains and is also referred to as a “sewer roach.”

American cockroaches tend to be particularly attracted to commercial buildings like restaurants, grocery stores, hospitals, and properties where food is prepared, as well as boiler rooms, basements, crawl spaces, sewers and drains because these provide warm and damp places to live. 

They’ll be found in piles of mulch, compost, and flowerbeds, and other areas outside of your home in the yard that provides sources of food, moisture, and shelter.

American cockroach outside
American roach outside. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org

However, this type of roach will get into your home and infest it when it is unable to find food or when weather conditions change such as being too cold outside.   

Large numbers of American cockroaches can also migrate into houses and apartments from sewer systems and in through plumbing, or from trees, shrubs, and overhanging branches close to buildings.[2]

How do American Cockroaches Get in Your Home?

There are a number of ways they (and other types of cockroaches) can find their way in,  such as:

  • Cracks and crevices in walls, around windows and door.  
  • Through air vents.
  • Cracks in foundations
  • Delivery boxes
  • Through open windows
  • Through gaps around utility pipes and plumbing
  • Gaps under doors
  • Up through drains from the sewer
  • Firewood
  • Garage

Read what attracts cockroaches in your home and the different ways they can get in.

The American Cockroach Diet

American cockroaches are omnivores, so they eat both plants and animals and they are not fussy about what they eat. 

Adult American cockroach feasting on a cracker
American cockroach feasting on human food. Image credit: Clemson University – USDA Cooperative Extension Slide Series, Bugwood.org

Outside your home, they prefer to dine on decaying organic matter such as leaves and fungi, and other small insects.  It also feeds on feces and rotting garbage.

Inside your home is like an open buffet for this scavenger and it will eat pretty much anything it finds including grease, paper, candy, hair, food crumbs, pet food that is uncovered or left out, dead insects, other dead roaches, and any fermenting foods. 

What Are Signs of an American Cockroach Infestation?

Finding a single huge cockroach in your house doesn’t necessarily mean you have an infestation, as it could simply have found its way in accidentally from your yard.  But if you’re noticing the odd one on a more frequent basis then it’s fair to say you’ve got an infestation. 

Where do American cockroaches live?  During the day, they like hiding close to sources of moisture such as sinks, bathtubs, and toilets.

There are few clues to look for if you suspect they are in your home and one of the obvious ones is spotting a live or dead one.  

Other signs to look for are their droppings or frass, which is larger than German roach droppings.  American roach frass has blunt ends and ridges to the sides and can be confused with mouse droppings.

Another indicator of an infestation is seeing their egg capsules.  Remember, these will be hidden close to food sources but they can also be found in, behind, and under appliances, in basements, and on ground floors.   

Can American Roaches Affect Your Health?

Yes, they can. In addition to being filthy insects, American cockroaches produce allergen proteins in their droppings, saliva, and urine, which can cause allergic reactions and asthma attacks in some people, particularly children.  This pest picks up bacteria, viruses, and parasites in unsanitary environments, which can cause serious health problems, such as diarrhea, dysentery, and typhoid fever.

What Kills These Large Roaches?

Getting rid of American roaches uses the same methods as you’ll find in the detailed guide to getting rid of cockroaches without an exterminator

The guide tells you exactly how to control these pests, which covers: 

  • Giving your home a deep clean and remove all sources of food, water, and harborage areas.  Roaches need these to survive and reproduce.
  • Use a vacuum with a HEPA filter to get rid of any live or dead cockroach bodies, or eggs, from the harborage areas.  A HEPA filter will help reduce any cockroach debris from being airborne.
  • Don’t leave anything in the sink to soak overnight; wash everything up when you’ve finished with them. 
  • Don’t leave pet food or water out or uncovered.  
  • Put food in airtight food storage containers. 
  • Wipe up any spills and foods.
  • Take your garbage out at the end of every day.  
  • Vacuum floors and dining chairs daily to pick up any dropped crumbs.
  • Monitor them with glue traps and place them close to where you’ve seen them,  which will likely be close to water and food sources. Make sure the sticky traps are flush against surfaces so they have to walk onto the glue and cannot escape.
Picture of cockroach sticky trap
Cockroach sticky glue trap for monitoring and trapping
  • When you know where their harborage areas are, you’ll then apply the gel bait in small, pea-sized amounts about eight to ten inches apart.   Place the gel bait underneath appliances such as the refrigerator, and near the water heater, and in any gaps, cracks and crevices. 
  • Supplement the gel bait with a powder such as boric acid or Avert Dry Flowable cockroach bait.  Both of them are effective at killing this huge species of roach, but it must be applied as a light layer and only in places where you haven’t placed the gel bait. 

How to keep American Cockroaches Out and Prevent Them Getting Back In 

There isn’t any way to completely eliminate the risk of them getting into your home from outside sources like deliveries, but there are some things you can do to help prevent or at least reduce the risk of reinfestation.

By keeping your home clean and denying them food and water, you limit their attraction to your home.

Cockroach harborages should be sealed with caulk around cabinets, plumbing, under sinks, and in other areas where there is a water source that will attract them.

Make sure any leaky pipes are fixed and damage to drywall around these areas is properly repaired. 

Seal cracks where electrical wiring enters the ways. 

These common pests can also enter your home through basement windows or the garage.  They can crawl under a door that doesn’t have a weather strip as they are able to squeeze through a gap that is only the height of two stacked pennies.[3] 

So seal cracks around your windows and doors, make sure the screens on your windows fit properly, and put weather strips on all external doors. 

Cockroaches like to hide in corrugated cardboard boxes and this is often where you’ll find them if they are brought in with a delivery, so get rid of these harborage areas, along with newspapers, and other clutter.

Seal spaces where plumbing or electrical wiring goes through walls with steel wool or other rough material.

Remove any leaves from window wells and guttering and make sure tree branches are not touching your home. If you are seeing roaches outside then it’s important to do this.

Put a cover or screen over any drains to prevent them from getting in, especially at night as this is when the majority of American cockroach activity occurs. 

It can be overwhelming seeing this large pest in your home and you might not want to try and eliminate it yourself, and you don’t have to.  Fortunately, since this is a common cockroach species, there are also many pest control professionals who can take care of them for you.

Our guide on how to choose a pest control company gives you some handy tips to help you find the right one.  Alternatively, fill in the form below for a no-obligation quote from pest control companies near you.

[1] http://entoweb.okstate.edu/ddd/index.html

[2] https://entnemdept.ufl.edu/ 

[3] https://www.nationalgeographic.com

I’ve been in the pest control industry helping people get rid of their unwanted pests for over 20 years, both in the UK and Canada.

As a licensed pest management professional, I’ve seen and treated just about every common household pest, insect, or rodent, you can think of. I’ve seen the damage caused when an infestation has been left too long and has become hard to get rid of.

For this reason, peststopsolutions.com was created. By having honest advice and the right guidance to hand, along with scientific evidence to back up claims, you are given information on the best eradication methods, as well as how to get rid of most pests yourself.