The smoky brown cockroach is an outdoor roach that mostly lives in planters and around forests or shrubs. It’s a large species that’s sensitive to changes in the environment and looks for areas of high humidity. It’s also a problem for homes in warmer climates.

“Smokybrowns” can carry diseases and spread bacteria picked up from sewers and garbage. They’re unpleasant pests to find around your house and shouldn’t be taken lightly.

If you’ve seen suspiciously roach-like insects in your garden, garage or home, read on to learn what smoky brown roaches look like, how to control an infestation, and how to prevent problems in the future.

How to Identify a Smoky Brown Cockroach

Smokybrown cockroach adult, nymph and egg beside a U.S. penny for scale

The smoky brown cockroach is aptly named after its color: a dark, glossy brown or uniformly mahogany color that’s consistent on both its back and underside. It looks a lot like the American cockroach, with a similar size and shape. However, the smoky brown roach lacks the yellow accents of the American species.

Smoky brown roaches grow to about 1 1/2 inches in length. Both male and female smoky brown cockroaches have long wings that extend past their abdomens. They use their wings to fly in search of food or to find a mate. A smoky brown roach also has antennae that are as long as or longer than its entire body.

Habitat and Distribution of Smoky Brown Cockroaches

Smokybrown cockroach range USA
Smokybrown cockroach distribution U.S.A. (in orange). Data courtesy of BugGuide

Smoky brown cockroaches are prevalent across the United States in places where humidity is high and temperatures are warm for at least some of the year. They’re an outdoor species, typically living among fallen leaves, woodpiles, planter boxes and similar habitats. You might also find them near your home, hiding in your water meter box, garage, shed, roof shingles or rain gutters.

Smoky brown cockroaches and other outdoor species sometimes struggle to survive indoors. They don’t usually come inside intentionally; instead, they might be carried in on firewood or in boxes that were stored in a garage or shed.

They’re also attracted to light and sometimes fly through open windows toward a light source. If they do come inside, they usually move into a crawl space, attic, or other upper-floor area where the temperature and humidity levels are higher.

Do Smoky Brown Cockroaches Come Into Contact with People?

To many people, seeing a big brown cockroach scurry quickly under a cabinet when they flick on a light is frightening and causes anxiety. Now imagine one suddenly flying across the room–not a pleasant surprise in the middle of the night!

Though their preferred habitat is outdoors, smokybrown cockroaches can still cause problems for homeowners. They’re an obvious aesthetic pest: no one wants to see large cockroaches crawling around their garden or flying around their patio lights.

Indoors, they search for food and water in kitchens and bathrooms. They’ll live and reproduce in poorly-ventilated areas that are warm and humid, like your attic. There, they can become a problem, hiding among cluttered boxes and laying egg cases. Their diets range from dead insects and dead leaves to starches–like those important documents filed away in the attic.6

Life Cycle of Smoky Brown Roaches

Illustration smokybrown nymphs beside ootheca
Two smokybrown nymphs beside egg cases

From the time it hatches, a smoky brown cockroach takes about 320 days to become an adult. The female cockroach carries its egg capsule—called an ootheca—for about a day before hiding it somewhere to hatch. Each tiny egg case (only about 3/8″ long) can produce as many as 45 nymphs.

Since one female can lay dozens of egg cases throughout its life, just a few adult cockroaches can create a large infestation in a relatively short amount of time and without much warning.

Nymphs (baby roaches) begin life with a much darker color than adults that also features two strips of white. The tips of their antennae are white, too. As they grow, they take on a more reddish color. You probably won’t spot nymphs, though: cockroaches are very careful about staying hidden (not to mention they’re quite small) at this vulnerable stage.

An adult smoky brown roach lives 2 to 6 months, on average.

Are Smoky Brown Cockroaches Dangerous?

Despite being categorized as an outdoor species, smokybrown cockroaches are still dangerous pests. They’re less likely than some other roach species to invade homes but can still come inside accidentally and cause problems.

Smoky brown cockroaches live in a variety of disgusting places, from piles of dead leaves and wet mulch to storm drains and sewers. They even eat bird droppings.

If they fly into your home, they’re going to bring lots of dangerous bacteria to your attic and, probably, your kitchen. They’ll contaminate cooking and eating surfaces as they search for food. Their skin also triggers some people’s allergies.

Tips for Controlling Smoky Brown Cockroaches

Cockroaches are extremely resilient insects and can be difficult to control without professional help. Smoky brown cockroaches are a common pest that should be treated seriously. Though they’re not immediately dangerous outdoors, seeing them near your house is a sign that they’ve found habitable conditions and will probably stick around.

Be careful when watering plants, as over-watering can help the smoky brown cockroach thrive. Dispose of leaf litter. Clear gutters and drains to remove standing water and the decaying organic material that roaches eat. You should also keep your trash cans closed tightly to prevent roaches from accessing food scraps.

Don’t risk bringing them indoors accidentally.

If you store firewood, stack it neatly away from your house. This will help keep it dry and ventilated–two conditions in which smokybrown cockroaches can’t survive. Trimming shrubs and raking mulch so that it’s dry and separated from the walls of your house removes more potential habitats.

Eliminating sources of food and water is often enough to control outdoor populations. Indoors, more aggressive steps might be necessary. You can use baits in your home to trap or kill smokybrown cockroaches. Baits attract cockroaches but are poisonous when eaten. To use them effectively, focus on areas closest to their suspected hiding places. Cockroaches typically live within a few feet of their food source.

If you’re worried about a large infestation putting your home in danger, contact a pest control professional. They can better identify the roaches’ entry points and target specific areas with insecticides or other treatments.

Steps to Prevent Smoky Brown Cockroaches from Invading Your Home

Illustration: Smokybrown cockroach entering home through crack in foundation

Preventing smoky brown cockroaches is a multi-step, ongoing project. It requires good cleaning habits and a plan for eliminating potential habitats. Start with the most important target for roaches: food.

Don’t make it easy for cockroaches to find food. Wash dishes and wipe kitchen counters every night to clean up crumbs and spills. Empty pet food containers at the end of the day. Sweeping and vacuuming frequently are also important.

Eliminating habitats indoors means organizing cluttered areas, such as your attic. Storing things neatly can go a long way toward eliminating places where cockroaches can lay egg cases. If conditions become very humid in your attic, it might be necessary to use a ventilation fan.

You should also take time to inspect your home or structure for cracks or holes that could let cockroaches in from outside. This includes your roof, where smoky brown roaches sometimes fly from trees to shingles. Sealing walls and using screens in every window will help prevent them from flying inside.

Always check firewood or items that were stored outside before you bring them in. You can deter roaches by using only a thin layer of mulch and keeping your landscaping clear of debris.

You can also apply cockroach control products around the outside of your home. Always read the warnings carefully, especially if you have pets or children who play outside.

Conclusion

If you live in an area that stays warm and humid for at least part of the year, there’s a chance smoky brown cockroaches will move into your garage, garden or even your attic. Don’t risk letting these pests spread bacteria around your home; start taking steps to prevent them today.

If you’ve seen smoky brown cockroaches around your home–inside or outside–it’s time to use the control tips above before they can reproduce and spread. Or, call a professional to begin targeted treatments and keep your home free from cockroaches and other pests.

Frequently Asked Questions

Do smoky brown cockroaches bite?

Bites from cockroaches are rare. They don’t bite to defend themselves like other insects. Cockroaches can bite but, while it’s possible, they’re much more likely to stick to their hiding places and any sources of food they’ve found. Smokybrown cockroaches will almost always run or fly away from a person.

Can smoky brown cockroaches fly?

Yes, smokybrown cockroaches can fly. They have long wings that they use to fly to food sources and habitats, including tree holes and roof shingles. They can fly away quickly from humans. Since they’re attracted to light, they’ll also fly into homes toward ceiling lights and lamps.

Do smoky brown cockroaches smell?

Smokybrown cockroaches don’t naturally give off a noticeable odor. However, smokybrown nymphs molt as they grow and their old skins can trigger allergies in some people. Additionally, smokybrown cockroaches move through dead leaves, drains, sewers and other unpleasant places, so they might carry odors with them.

How can I control smoky brown cockroaches naturally?

Smoky brown cockroaches are more sensitive to the environment than some other species. They need warm, humid conditions to survive. If the air is too dry, they’re likely to become dehydrated. Some of the most effective natural methods of controlling smoky brown cockroaches include reducing humidity, improving ventilation and removing food sources.
Decluttering storage areas and reducing humidity in your attic can deter smoky brown roaches from breeding there. Piling firewood neatly and using only a thin layer of mulch also reduces moisture.

Sources:

  1. Smokybrown Cockroach, Periplaneta fuliginosa. Oklahoma State University: Entomology & Plant Pathology. Retrieved from http://entoplp.okstate.edu/ddd/insects/smokybrownroach.htm
  2. Brown, Wizzie, et al. Cockroach Biology and Management. Texas A&M AgriLife Extension. Retrieved from https://citybugs.tamu.edu/files/2016/07/E-359-Cockroach-biology-and-management-2012.pdf
  3. Koehler, P.G., et al. (2011) Cockroaches and Their Management. University of Florida IFAS Extension. Retrieved from https://edis.ifas.ufl.edu/pdffiles/IG/IG08200.pdf
  4. Sutherland, Andrew M., et al. (2019) Cockroaches. Pest Notes: Cockroaches. Retrieved from http://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html
  5. 5. Hopkins, John D. Cockroach Identification and Management for the Homeowner. University of Arkansas Division of Agriculture. Retrieved from https://www.uaex.edu/farm-ranch/pest-management/docs/Cockroach%20ID%20and%20Management%20for%20the%20Homeowner.pdf

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