German Cockroach: All You Need to Know in a Nutshell

The German cockroach is a common household pest that often resides in areas with human habitation. This brown, 12 to 17 mm long insect is easily identified by the two dark brown stripes located on its body region, just behind the head source.

These cockroaches can be quite the nuisance, as they are known to produce allergens that may induce asthma in people. Their ability to move between connected apartments and buildings, as well as being transported through human activities, such as food and equipment dispersal, makes them difficult to control source.

German Cockroach Overview

Appearance and Characteristics

The German cockroach (Blattella germanica) is a small species known for their unpleasant reputation. Some key features include:

  • Light brown to tan color
  • Two dark lines on the pronotum
  • Winged but rarely fly
  • Adults are about 1/2 to 5/8 inch long

Habitat and Distribution

Originating from Europe, these pests have now established themselves globally. They are commonly found in:

  • Kitchens and bathrooms
  • Warm, humid environments
  • Close proximity to food and water sources
  • Residential and commercial buildings

German cockroaches proliferate quickly, making control and prevention crucial. For more information, visit this resource.

Infestation and Control

Signs of Infestation

  • Spotting live or dead cockroaches
  • Finding droppings similar to ground coffee or black pepper
  • Discovering egg cases or shed skins
  • Detecting a musky odor

A German cockroach infestation is often identified through the following signs:

  • Live or dead cockroaches.
  • Droppings that look similar to ground coffee or black pepper.
  • Egg cases (oothecae) and shed skins.
  • A distinct musky odor, especially if the infestation is severe.

Prevention Methods

  • Keeping living spaces clean and dry
  • Sealing cracks and crevices
  • Fixing water leaks
  • Storing food in sealed containers

To prevent a German cockroach infestation:

  • Maintain cleanliness and good sanitation in living areas.
  • Remove clutter to eliminate potential hiding spots.
  • Fix any water leaks to keep areas dry.
  • Seal cracks and crevices to prevent entry.
  • Store food in pest-proof containers.

Pest Control and Extermination Techniques

  • Regular inspections
  • Sticky traps
  • Gel baits
  • Bait stations
  • Vacuuming with a HEPA filter
  • Diatomaceous earth and boric acid dust
  • Insecticides and roach sprays

Here are some commonly used German cockroach control and extermination techniques:

  • Regular inspections to detect infestations early.
  • Using sticky traps to locate harborage areas.
  • Applying gel baits for targeted control.
  • Setting up bait stations, which can provide long-term control.
  • Vacuuming with a HEPA filter to remove cockroaches and their allergens.
  • Applying diatomaceous earth or boric acid dust to cracks and crevices.
  • Applying insecticides and roach sprays as directed, ensuring safety precautions are followed.
Technique Pros Cons
Sticky traps Non-toxic and easy to use May not eliminate large infestations
Gel baits Targeted and effective control May require re-application
Bait stations Long-term control Less effective in highly-infested areas
Vacuuming (HEPA filter) Reduces allergens and cockroaches Not a stand-alone solution
Diatomaceous earth Safe and chemical-free Slow-acting
Insecticides and sprays Quick results Can pose health risks if misused

It is important to combine multiple extermination techniques for effective German cockroach control and maintain preventive measures to keep them from returning.

Reproduction and Lifecycle

Eggs and Development Stages

The German cockroach has a three-stage life cycle: egg, nymph, and adult. Female cockroaches lay 12 to 36 eggs at a time, which are contained within a protective bean-shaped capsule called an ootheca.

  • Eggs: Protected in the ootheca.
  • Nymphs: Generally dark with two distinct dark stripes.
  • Adults: Light brown to tan, with two dark stripes on the pronotum.

Mating and Reproduction Cycle

Males attract females by raising their wings above their abdomens, revealing a dorsal gland. Female German cockroaches produce four to eight egg capsules during their lives. These capsules may be yellowish-brown in color and are often seen protruding from the end of the females’ abdomen.

Lifespan and Population Growth

As nymphs mature and develop, they gradually take on adult characteristics and coloration. The lifespan of German cockroaches varies, but their rapid reproduction capabilities can lead to significant population growth in a short time. This growth can cause issues in human habitats, as they are closely associated with human habitation and can produce allergens that induce asthma.

Comparison Table:

Feature Males Females
Size 5/8″ (1.6 cm) long Similar in size
Coloration Pale-brown or tan, 2 stripes Same coloration
Abdomen Slimmer, yellower, more tapered Broader, carries egg capsule
Wings Extend almost to the abdomen tip Similar in wing length
Reproductive behavior Raises wings to attract females Produces oothecae with eggs

German Cockroach Hazards and Health Risks

Allergies and Asthma

German cockroaches can be a significant factor in developing allergies and asthma, especially in children. Their shed skins, feces, and saliva contain allergens that, when inhaled, can trigger allergic reactions and cause asthma.

  • Example: exposure to German cockroach allergens can lead to:
    • Sneezing
    • Itchy eyes
    • Coughing
    • Trouble breathing

Disease and Bacterial Transmission

Besides being inconvenient household pests, German cockroaches can pose health risks due to their ability to transmit bacteria and disease-causing microorganisms. They can carry pathogens such as Salmonella and E. coli, which can lead to illnesses.

  • Comparison table:
Disease-causing Microorganisms Health Risks
Salmonella Food poisoning, stomach cramps, fever
E. coli Diarrhea, abdominal pain, kidney failure

Contamination and Odors

German cockroaches can contaminate food and surfaces they come into contact with, as they carry germs and bacteria on their bodies. Additionally, they can produce a musty odor that can be bothersome to humans.

  • Contamination examples:

    • Droppings on kitchen counters
    • Walking on uncovered food
    • Leaving bacteria-laden debris
  • Musty odor: The presence of German cockroaches can result in an unpleasant smell in your living spaces, which might indicate a high level of infestation.

Home Management and Sanitation Practices

Kitchen and Bathroom Maintenance

German cockroaches thrive in places where they have access to food, water, and dark hiding spots. Since kitchens and bathrooms offer these conditions, maintaining cleanliness is crucial.

  • Regularly clean counters, sinks, floors, and appliances to remove crumbs, grease, and moisture.
  • Pay close attention to hidden spaces such as under refrigerators and behind stoves where food debris and droppings can accumulate.
  • Avoid leaving dirty dishes out in the sink or on countertops for a long time.
  • Store pet food in airtight containers and avoid free-feeding pets, as leftover pet food can attract cockroaches.
  • Regularly empty and clean trash bins where food waste accumulates.

Sealing Cracks and Crevices

Cockroaches can enter your home through small openings. Sealing these entry points is essential for roach control.

  • Inspect your home for cracks and crevices in walls, baseboards, and floors.
  • Use caulk or sealant to close gaps around pipes, windows, and door frames.
  • Install door sweeps to prevent cockroaches from entering under doors.

Managing Food Sources

Controlling food access is a vital part of good sanitation and reduces the chances of a German cockroach infestation.

  • Keep food in airtight containers or refrigerators.
  • Avoid leaving food items on countertops and open shelves.
  • Regularly clean food storage areas to remove crumbs and spills.
  • Dispose of food waste promptly and securely in closed bins.

By following these home management and sanitation practices, you can effectively prevent and control German cockroach infestations.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – German Cockroach

 

Can you please tell me what this is?
December 20, 2009
I just moved into a new place with my three year old son. In the last 2 days, we have found three of these critters in the house. We found one in the pantry, one on the wall in the hallway, and one in the shower. I’m worried that it may be a cockroach or something, but I’m not sure. Any information you can offer would be very much appreciated.
Concerned in Florida
Saint Augustine, FL

German Cockroach
German Cockroach

Dear Concerned in Florida,
The two parallel dark streaks on the pronotum identify this as a German Cockroach, Blattella germanica, one of the most reviled insects that infest dwellings.  Eliminating them from an infested home might be a losing battle.

German Cockroach
German Cockroach

Thank you very much. That confirms my suspicion, and makes the decision for me….I will be moving.  I greatly appreciate your time.

Letter 2 – German Cockroach

 

Subject: What’s this bug?
Location: New York City
December 15, 2013 3:33 pm
Hi,
We’ve seen quite a few of these bugs in our kitchen. They are not fast movers and they have very long antennas. We had an exterminator come in but we are still killing at least one bug each day. I’m thinking they are some sort of water bug? Please help us ID these!
Signature: A

German Cockroach
German Cockroach

Dear A,
This is a Cockroach, and though your photo is quite blurry, based on your description, we believe this is a German Cockroach.  For additional information on the German Cockroach, see BugGuide which states:  “Like most cockroaches, the German Cockroach is nocturnal. It is a major pest of residential and commercial structures.  Some people can develop severe allergies to cockroach parts, feces, and oils.   Females carry the ootheca for up to a month, dropping it just before the eggs hatch.”

Letter 3 – German Cockroach

 

Subject:  Hello!
Geographic location of the bug:  California, Long Beach
Date: 10/13/2017
Time: 11:14 PM EDT
There’s lots of these little buggers in an old building that I live in. They generally stay out of sight and hug crevices and other areas, would love to understand what they are attracted to!
How you want your letter signed:  Anything is fine

German Cockroach

This is a German Cockroach.  According to BugGuide:  “Infests human dwellings and workplaces.”

Letter 4 – German Cockroach Infestation

 

Kitchen bugs
Dear Bugman,
For the last few months there have been bugs in our kitchen, they have begun increasing in numbers and are getting rather disturbing as they move very quickly. When you turn the lights on you just catch glimpses of them as they dart all the way across counters to hidden cracks in the cupboards. We are getting frustrated with them as we are finding them even in places that we have recently cleaned and disinfected like the silverware drawer. We were hoping you could tell us what they are and what we can do about it since there numbers are starting to increase rapidly. Attached are several pictures. Their length when full grown appears to be about 1/2" to 5/8" and their width is about 1/4". Thank you.

You have a German Cockroach Infestation.

Letter 5 – German Cockroach infestation

 

Subject: Help!
Location: Lethbridge Alberta Canada
December 8, 2014 9:30 pm
My husband and I just moved into an new older apartment about a month ago. Since we moved in we can’t seem to get rid of these bugs that are everywhere. The main plae we find them is in the kitchen and bathroom but they have been known to be found climbing walls in our bedroom and scurrying across the floor in other rooms of the house also. They are driving me nuts. We don’t know what they are so we can’t even figure out how to get rid of them. They range in size from teeny tiny to about the size of a nickel in length. Some have wings and others don’t but I have never seen them fly. I thought they would go away after we settled in but they haven’t. I also believe they are leaving poop on my counters as I often find a black almost sand like substance on them that has no other valid reason to be there as we don’t even do much cooking in our kitchen. I hope the pictures help in identifying this bug so we can finally get rid of it. Thanks for your help.
Signature: Ashley

German Cockroach
German Cockroach

Dear Ashley,
You have an infestation of German Cockroaches, and since they are in various stages, they are reproducing and thriving in your apartment.  The larger winged individuals are the adults.  German Cockroaches thrive in contact with people and they are one of the few Cockroach species that infest homes, restaurants and other places where they get food and shelter.  You can verify our identification on BugGuide.

German Cockroach Nymph
German Cockroach Nymph

Letter 6 – German Cockroach with Ootheca

 

Subject:  Bug
Geographic location of the bug:  Lake county il
Date: 08/14/2018
Time: 12:12 AM EDT
Your letter to the bugman:  Can you identify this bug?
How you want your letter signed:  Jessica

Female German Cockroach with Ootheca

Dear Jessica,
This is a female German Cockroach and she is dragging around her ootheca or egg case.  According to BugGuide:  “Nocturnal; major pest of residential and commercial structures. Some people can develop severe allergies to cockroach parts, feces, and oils.  Females carry the ootheca for up to a month, dropping it just before the eggs hatch.” 

Letter 7 – German Roach Question

 

Dear What’s That Bug:
Thanks for your informative web site. I had the misfortune of moving into an apartment that was infested with German cockroaches about a month ago. On average I see around 10 of the critters a day throughout the unit, sometimes more. After negotiations with my landlord, I’m planning to move out in the next few weeks but I’m terrified of taking these pests with me. I took very few clothes to the apartment and never used two of the closets nor did I ever use the kitchen normally. Most of my belongings are in lidded plastic bins and anything that has remained in a box I plan to re-pack in a plastic bin. I plan to get rid of my dresser drawers as I often saw roaches on them. How worried should I be about taking these things with me? Can you recommend anything else I can do in terms of my furniture to help prevent them coming with me? Any advice would be appreciated.
Thank you bug man!
Nervous in Virginia

Dear Nervous,
You have every cause to be concerned. These roaches are insidious. Unfortunately, you can never be positive that you are not transporting tiny immature roaches to your new apartment. I don’t normally endorse fumigation, but it would be wise to find some way of poisoning the stowaways who might be infesting your belongings. You might want to take your clothes to the laundermat and wash them before going to your new place. Do not return them to the site of the infestation or you may get new hitch-hikers. Good luck.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Assistance Requested from our Readership: What are the Mysterious Droppings???

 

Ed Note: It is impossible for our tiny staff to respond to every email, but if a person writes back indicating that a previous email was unanswered, we will attempt to provide a response.  In this particular situation, when a new email was sent two weeks later, there were no images, so rather than to sort through hundreds of emails, we responded accordingly, and then we received additional written information, but no photos.  Now our curiosity was truly piqued, so we tracked down the original letter which contained the images on this posting.

Mysterious Droppings

On Sun, Oct 17, 2010 at 7:02 AM
I haven’t heard anything from you,did you get my e-mail?

There are no photos attached.

I sent three but its hard to them they look like coffee grinds they are ale=ways in the same to places in the house. they accumulate on a white wooden box that covers our water heater, the other is on a glass and wood coffee table.  My boyfriend and i will clean theses ares and in a day or two the tiny brown specs will come back. they are smaller then coffee grinds. I video monitored it one night and nothing happened for two days i stopped and they appeared again.  I soaked wood over water heater with a very strong bug killer and in a day they cam back.  There are no holes in the ceiling so its not dropping, it not falling from ceiling fan because it would be spread out more.  We are losing our minds because we don’t know what it is so we don’t get rid of it. the house was built in the 1940’s we do see termite fras brown or black on the wood floors here and there.  Could something be picking up the fras and dropping it in the same two places.   I sold pest control in the 90’s so I know a little about it.  But this is mind boggling , we joke and say a ghost is doing it,lol  but we are really getting upset with it.  the economy does not allow me to hire someone right now.  I just heard my company is going to lay people off, so i have to watch every dime.  Please if you could just tell me what to do or a website that could help me i would so appreciate it.  Thank you for the time in reading this short novel.

Ed. Note:  Original Letter located
mysterious bug droppings
Location:  St .Augustine fl
October 3, 2010 11:46 am
We are losing our minds over this and so is all our friends. we have a wooden box covering a short hot water heater. On the top we wake up to find tiny brown spots in the same circle we look up no holes in the ceiling we inspect box no holes we clean it off and it always comes back. And get this on our glass coffee table in one corner always the same. So I said I know i will put down glue sticky traps and you won’t beleive this but brown dots smaller then coffee grinds on the glue traps an no sign of whats putting them there. Please help us we rent here and we are finally happy where we live but this is so annoying. we live in st.augustine ,fl
Signature:  jersigypci

Mysterious Droppings

Dear jersigypci,
We can see from the time stamp of February 1, 2006 that this unimaginably disturbing phenomenon has been plaguing you for more than four years and we cannot fathom how you have managed to endure it, but tragedies are all relative.  We cannot identify anything in your photographs and we are unable to provide you with any explanation for this horrific occurrence.  We would recommend professional help or perhaps just rent Stanley Kubrick’s The Shining and be thankful that your situation isn’t worse.  We actually can suggest one additional alternative that may provide closure.  Since we are posting your emails along with all of your photos, which we were able to locate, our readership may be able to help solve your mystery before your minds are totally lost.  Gentle Readers, please post a comment if you have any suggestions.

Mysterious Droppings

oh well thanks any way i thought if anyone could help us it would be you, since i heard how awesome you all were. i guess we’ll just have to live with iy.

Had you checked back, you would have seen that our readers have been posting comments.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

11 thoughts on “German Cockroach: All You Need to Know in a Nutshell”

  1. My guess would be that these are not any kind of “droppings” at all. Perhaps in reality these particles are everywhere in your house, but you only notice them when they are on a white surface or on a horizontal glass surface. I would suggest that you check to see if these specks can actually appear pretty much anywhere in your apartment. Why don’t you try leaving a few clean white plates out in various localities in the house, and see if you get the same dark specks on them?

    If you do, I would be inclined to think that this is simply everyday dirt. I don’t know if you live in or near a city, but you would not believe what drops out of the air every day in my apartment in NYC, more so closer to the windows of course: lots of small dark particles, some of which are quite sticky.

    We tend to think that fine dust is the only “normal” thing to settle on a surface, but we don’t realize there is a lot of larger particulate matter that drops out of the air also (tiny fragments of rubber from thousands of car tires wearing out, tiny pieces of earth, etc). And remember that every surface of every item in your house (including your body) constantly sheds particles too. It’s an untidy world, all in all. I suspect this is due to entropy, not bugs.

    Susan J. Hewitt

    Reply
    • Excellent suggestion Susan. Daniel grew up in Youngstown, Ohio while the steel mills were going full bore and there was black, coffee ground grit on everything.

      Reply
  2. I have a similar infestation at one location inside the house. Except that above on the wall near the ceiling is a tiny 0.06 inch diameter hole that was hardly noticeable until I got real close. I cleaned up all the droppings off the top of our file cabinet (hundreds of them) and spackeled up the hole. Two weeks later more droppings appeared and a new hole next to the one I patched. Any suggestions before I drill a larger hole in the wall, stick a funnel in the hole and spray it with insecticide? The wall is drywall.

    Reply
  3. Keep in mind, not all roaches that might wander into a house are nasty home infesting bits of yuck that require the Orkin man. If you live near or in the woods you might have a wood roach fly into your house. Yes, a flying roach that is attracted to light. They only eat rotting logs and leaves though, so they die if they get in your house. My neighbor found one and she was SCREAMING on her front lawn. A little bit of knowledge is a good thing. 😉

    Reply
  4. Some people say the same thing about bed bugs. How can you not know what they look like?
    It’s easy. If you have never lived in a city, never lived in an apartment – chances are very high that you have never seen a cockroach. I am sure that there are plenty of people who haven’t.

    Reply
  5. Ashley to get rid of them buy Advion roach gel bait from ebay or walmart online only it’s not sold in stores. It comes in a 4 pack of plastic syringes. And you will get instructions on how to use it. This stuff really works it’s what exterminators use.

    Reply

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