Smokybrown Cockroaches – Why This Roach Hides in Your Attic

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

What Are Smokybrown Cockroaches?

Smokybrown cockroaches (Periplaneta fuliginosa) are an easy to recognize peridomestic species of roach because of their uniform mahogany-brown color and lack of markings on the pronotum. 

The large Smokybrown roach can fly and is typically nocturnal.  This species lives in warmer climates so it is found in southern US regions and is well established in north-central Florida. It can also be found in Australia, Europe, and Japan. 

Smokybrown cockroaches need access to fluids or moisture every two to three days because they lose moisture through their cuticle at a high rate. In fact, they have one of the highest levels of moisture loss out of any species of cockroach, which is why they live in high humidity areas.  

Picture of an adult smokybrown cockroach
Picture of an adult smokybrown cockroach. Image: Pest and Diseases Image Library, Bugwood.org

Are Smokybrown Cockroaches a Pest?

Yes, the Smokybrown roach is a pest and just like other cockroaches, they carry harmful bacteria that they leave behind on any surfaces they crawl across.  This bacteria can cause us some nasty illnesses.     

In addition to transmitting bacteria, their saliva and skin contain proteins that may aggravate asthma or allergies. 

What Do Smokybrown Roaches Eat?

This roach is a scavenging detritivore, which means in outside environments it will eat decaying plants, dead animals, as well as other things such as fecal matter.

As with other species of roach, the smokybrown is not fussy about what it eats which can include crumbs, leftover food, pet food, and dead insects, for example. 

Read more about what attracts roaches and the cockroach diet.

What Do Smokybrown Cockroaches Look Like?

  • Mahogany-brown in color throughout and they don’t have any markings on the pronotum like other roaches.  (See our cockroach images page)
  • Smaller than its close relative the American cockroach at around 1.25 – 1.5 inches (32 – 38 mm).
  • It is possible to tell apart the female from the male by the notch on the end of her abdomen. 
  • Both sexes have fully developed wings that cover their abdomens so they can fly, and you’re more likely to see them flying on hot summer evenings.
Male and female smokybrown cockroaches picture
Image showing female and male smokybrown roaches. Daniel R. Suiter, University of Georgia, Bugwood.org

What Do Smokybrown Cockroach Nymphs Look Like?

  • The younger nymphs are a shiny black color with white-banded antennae and white markings on the body.
  • They are around 3/8 inch long.
  • As they mature their color changes to reddish-brown and then to the mahogany/smoky brown color as they become adults. 

Life Cycle of the Smokybrown

Adult smokybrown cockroach females lay around 18 egg capsules, or ootheca, during their lifetime, each containing about 26 eggs that hatch in approximately six weeks.  

Usually, dark brown to black in color, the egg capsule measuring about 1/2 inch (11-14 mm) is larger than the ones produced by the Australian or American cockroach.  The female sticks the egg cases to a surface with secretions from her mouth and covers them with materials to blend them in and conceal them from potential predators.

This species can also be spread to other locations as the egg casings have been found attached to cars and RVs.   

When the nymphs are born, they will go through a series of molts before they become adults.  Females molt 10 to 12 times, while males molt 9 to 11 times.  

However, their development is dependent on temperature, so in the warmer summer months with temperatures around 80ºF (27ºC) a newborn can reach adulthood in as little as 5 months, but at 59ºF (15ºC) it can take up to 2 years.[1] 

How Long Do Smokybrown Cockroaches Live For?

The lifespan for adults is around 7 months but they can live for 2 years in the right conditions.  The female smokybrown roaches tend to live slightly longer than the males.[2]

What Attracts This Pest to Your Home?

As this species is peridomestic, it generally spends most of its life outdoors living in the landscape around your home, so you’ll find them in the following: 

  • Mainly in tree holes
  • In leaf litter
  • Mulch
  • Planter boxes
  • Lumber and firewood piles
  • Greenhouses
  • Rain gutters, soffits, and eaves, and other moisture-prone areas. 
  • They can also be found in sewers.  

But how do they enter your home?  What attracts cockroaches in your home? Well, they could be brought in on firewood, or have flown through a gap in a door or window. 

If the weather changes dramatically, they also look for ways in, so foundation wall cracks and gaps around utility lines can provide them with an entry point.

Attics and crawlspaces are common harborage areas for smokybrown roaches because they often have poor ventilation and are high in humidity and tend to have more moisture. 

In addition, they may also be found in basements and garages, as well as in a fireplace chimney, if you have one. 

Whether outdoors or indoors, this species of cockroach needs warm, poorly ventilated, sheltered areas with high humidity to ensure sufficient moisture, as they are prone to drying out. 

Signs of a Smokybrown Cockroach Infestation in Your Home

Since these roaches are nocturnal foragers, a roach flying around a room doesn’t necessarily mean you have an infestation as it could simply have been attracted to the light in it.  

However, the tell-tale signs of a cockroach infestation are the same for all species, and signs of a smokybrown infestation include:

  • Starting to see them more frequently in the kitchen and bathrooms, and at the entrance to the garage and crawlspaces.
  • Finding dead roaches – this is probably caused by dehydration.
  • Egg capsules.
  • Frase (fecal droppings).

Controlling Smokybrown Cockroaches

When you have a Smokybrown roach infestation in your home, you will target your control measures on the attic and the outside as this is where their primary harborage and breeding grounds are. 

Outside

  • Check for any cracks in foundations walls, and where different types of building material join together (eg. bricks and vinyl) and seal any gaps you find.
  • Look for gaps around utility pipes, windows, and doors.  Inspect the vents – do they all have insect screens to prevent pests from getting in?
Cockroach entry point from wall and pipes
Seal gaps around utility pipes to seal roach entry points
  • Are there any cracks in the chimney, soffits, roof joints, fascia boards, gutters?  If so, these need to be sealed as they are all possible entry points.  A pyrethrin aerosol can be sprayed into these gaps to flush out any roaches. The gaps can be sealed with an appropriate sealant. 
  • Stack firewood and piles of lumber away from your home and keep them covered and off the ground.  If it’s covered, it won’t get as wet and is less likely to provide a harborage site for this pest. 
  • Tree holes provide the ideal hiding places for these big cockroaches as they are moist and have very little airflow to cause dehydration, so we want to limit these harborage sites and fill the tree holes with sand.   
  • Remove any thick ground cover, leaf piles, and dead leaves and reduce an overgrown garden to limit potential hiding and breeding places. 
  • Fix any outside leaky taps and take away all water sources and don’t overwater plants. 
  • Store outside garbage, pet food, and recyclable items in bug-proof containers.
  • Make sure all windows have properly fitted screens and gaps are filled around windows and doors. 
  • Install weather strips on doors so roaches cannot crawl through the gap between the door and floor. 

Read: Why you have roaches outside your house.

Inside 

Good ventilation in the attic and crawl spaces is key here as it reduces the levels of humidity needed for them to survive.  

  • The best solution to prevent Smokeybrowns breeding and living in your attic is to ensure there is enough airflow, so, if you can, check that the soffits and other vents are not blocked.
  • Check vents are screened preventing unwanted pests from getting in.  
  • Good sanitation is vital for getting rid of cockroaches as they need food, water, and shelter to survive.  As these large cockroaches like to hide in boxes, stacked paper, and cardboard materials, especially in dark, damp environments, it is crucial to reduce clutter, especially in the attic.
  • In the kitchen keep countertops clean and don’t leave dirty dishes in the sink overnight. 
  • Before you go to bed, empty pet food bowls or keep them completely covered.
  • Regularly vacuum the floor and chairs to remove any dropped crumbs.
  • Your vacuum also comes in handy to remove any live cockroaches you find.  
  • To get a better idea of where their harborage areas are, put down sticky glue traps and monitor the number of roaches caught on them over a few days.  
Picture of cockroach sticky trap for monitoring roach levels
Cockroach sticky glue trap for monitoring and trapping
  • Gel baits are effective at killing roaches quickly and you’ll want to apply pea-sized dots of gel bait as close to their harborage sites as possible.  Click how to apply cockroach gel bait

As mentioned, this species of cockroach needs protected hiding areas where there is very little airflow and it also needs regular access to moisture to stay hydrated – taking these away is highly effective in eliminating them naturally.    

Recommended reading: How to get rid of cockroaches without an exterminator, details what the signs of an infestation are, where to look, and what steps to take to remove these pests.

During the summer months, Smokybrown roaches will be congregated mostly in the soffits, so the bait is best applied here.  HOWEVER, THIS IS BEST LEFT TO A PEST CONTROL PROFESSIONAL TO DO FOR YOU.  

Not everyone is comfortable going up into the attic and carrying out their own pest control and this is completely understandable, especially from a safety aspect.  The best way to remove these roaches from your home is to hire a professional pest control company. They will come to your home, confirm the species of roach, and eliminate the smokybrown roaches for you.

[1] pct technicians handbook 

[2] https://extension.okstate.edu/programs/digital-diagnostics/insects-and-arthropods/smokybrown-cockroach-periplaneta-fuliginosa/index.html

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.