German cockroaches are small residential cockroaches that have a length of about half an inch and that have colors like tan and almost black, with two dark streaks that are almost parallel. This species is the one that has made people have a generally bad impression of cockroaches.
The insect has wings, but they are not meant for flying. Despite this, the insect can glide when it feels in danger. Being closely related to another species called the Asian cockroach, the German cockroach has a very similar appearance to the Asian one, and people may not be able to differentiate them. Only a practiced eye can see the differences.
German Cockroach Behavior
This species of cockroach can be seen traveling along the edges of the walls in your home, especially at night. The insects try to be close to the smallest cracks that they can find in the walls, so they can flee when you turn on the lights.
German Cockroach Diet
In terms of diet, German cockroaches are omnivores and scavengers. Most of their food sources consist of starches, meat, fatty foods, and sugars.
When they can’t find real food, German cockroaches can eat soap, toothpaste, and glue. They can even become cannibalistic, eating each other’s legs and wings if they get sufficiently hungry.
German Cockroach Habitat
The insect’s habitat is the human building, where it can find food sources in kitchens, bathrooms, and other areas. While there are many insects of this type in households, they can be found in great numbers in restaurants, hotels, food processing facilities, nursing homes, and other similar buildings.
They try to keep themselves as close as possible to human dwellings because they cannot resist outside when the weather is very cold. The most common time of the day when you will see the German cockroach is the evening. You usually see it during the day only when the population is scattered.
Signs of German Cockroach Infestations
One of the common signs that your household is infested with German cockroaches is finding roach droppings: pepper-like material often found in drawers and countertops. There are also stains from the fecal matter of the insect. You may find these dark spots and smears in room corners, around wall openings and small cracks, and along the door tops.
A very ugly thing that you may notice is the presence of egg capsules. These capsules are carried by the female for a while and then the capsules remain empty in certain areas of your home. Because the German cockroach secretes various substances that smell, a musty smell will be felt in a home in which the cockroach populations are large.
German Cockroach Reproduction Cycle
The German cockroach has a faster reproductive cycle than any other species of residential cockroach, as warm weather accelerates the egg-laying process. From the egg stage to the adult phase, fifty to sixty days can pass.
An ootheca can develop inside the female’s abdomen. This ootheca is translucent in the beginning and it becomes white and then pink. In the end, the colors become dark red-brown.
A female German roach can produce thirty thousand cockroaches during a period of one year. The cockroach population usually doesn’t grow as fast as it may seem, especially because of insufficient food and cannibalism.
Are German Cockroaches Harmful to Humans?
Yes, they are, because they can transmit many types of bacteria, parasitic worms and other human pathogens. In fact, there is only one species of cockroach that is as dangerous for humans as the German cockroach and this is the American cockroach. They can spread airborne allergens because of the offspring’s production speed.
How to Prevent and Control German Cockroaches
You can only prevent and control German cockroach infestations through sanitation and exclusion. To do this, you need to identify places where German roaches enter your building; they can enter tiny cracks and crevices, so look for openings very carefully.
Seal these potential openings (silicone caulk usually works well) and then perform a deep cleaning of your building or vehicle (yes, German roaches can infest vehicles too).
Utility entrances, stoves, cupboards, and even outdoor vegetation might need cleaning. Address any water leaks (German roaches need water more frequently than food), and seal any food in plastic or metal containers. Poor sanitation facilitates German roach infestations, so keep your place as clean as possible.
An interesting (and annoying) aspect of German cockroaches is that they adapt to certain control measures. Sugar baits with poison, for example, were used in the past, but the insect now refuses to eat sweetened baits. For this reason, pest control professionals often recommend rotating between different insecticides.
Ways to Get Rid of German Cockroaches
For more details, you can read our full German cockroach elimination guide but here are some of the primary insecticides used for treating German cockroaches infestations:
- carbamate
- organophosphorus
- insect growth regulator
- pyrethroid
- amidinohydrazone
The main problem with German cockroaches is that they are extremely resilient. The above insecticides (and others) help eliminate German roaches, but infestations are really, really tough to fully eradicate, especially for a group of apartments because all apartments an apartment building need to be purged of roaches. If you use insecticides in a single apartment, the German roaches from other apartments can come and repopulate the treated apartment after the insecticide effects diminish.
A Few Things to Keep in Mind
The German cockroach is the most widespread species of cockroach in the United States, but it can also be found all over the world. It is not just a disgusting creature, but also one that carries germs. The diseases that it can spread are Salmonella, Typhus, E.coli, and others. Wherever there are food leftovers, you see these nasty bugs when you turn on the light, fleeing from your presence.
Avoiding German cockroaches is nearly impossible if your house is infested with them. They will often appear out of nowhere and ruin your mood, even destroying your appetite for food, because they mostly appear in the kitchen.
Even if you don’t have such roaches in your apartment, you can surprisingly bring them in a bag or a box when you come home from the country. It is enough for one bug to give birth. An infestation can begin in your home, and you will have to deal with it.
Further German Cockroach Resources
- If you find a baby cockroach in your home, read this.
- German Cockroach: Biology, Identification, Control (Blattella Germanica) – NC State Extension
- Think you have cockroach bites? Here’s how to know for sure.
