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Identification, Prevention and Pest Control of German Cockroaches


Adult German Roach

Adult German Cockroach

Courtesy of Erling Olafsson

Latin Name:

Blatella Germanica

Common Name:

German cockroach, or German roach

What Adult German Roaches Look Like:

The adults are visually distinguished from other roaches by their smallish size, medium brown color, and two short stripes on the back of their head going from front to back. These stripes are located on the pronotum, a plate that covers part of the head in front and the base of the wings in back. An adult is long and slender, about 1/2 to 5/8-inch long and 3/16 inch wide.

What Baby German Roaches Look Like:

German cockroach hatchlings are round or teardrop-shaped and about the size of a typed period. The roach body shape changes from rounded to teardrop-shaped then their final elongated cigar-like shape. Their coloring changes as they grow. The young start as very dark brown with a small tan area on their back, while the adult has a nearly all light to medium brown body and the characteristic two parallel dark stripes on the pronotum.

German Roaches vs Asian Roaches:

The German roach is almost impossible to visually differentiate from the Asian roach, which is much less common. Found primarily in the southern United States and Japan, the Asian cockroach is very unlike its German cousin in behavior, as it lives outdoors and is attracted to light, and flies.

Where German Roaches Live:

The German roach prefers the kitchen, especially tight crevices. Their preferred hiding spots are hinges of cabinet doors, the upper interior corners of cabinets, underneath sinks and refrigerators, and behind walls. Near these hiding spots you may see their fecal pellets which closely resemble coffee grounds or ground pepper.

The German cockroach will also hide in pedestrian door hinges, between baseboards and floors, and the joint where the ceiling and wall meet. Additionally, you may find them inside any electronic device or appliance, between warm plugged-in transformers and their outlets, and computers.

Health Impacts of Cockroaches:

These roaches routinely feed on garbage and thrive near damp, bacteria-laden environments. As a result, German roaches are known to carry pathogens of some 40-50 diseases. Although not actually proven to cause any diseases, German cockroaches are commonly suspected of spreading illnesses. Some experts believe their discarded skin castings are the number one trigger of asthma in urban environments.

Where German Roaches Come From:

German cockroaches are hitchhikers on people and possessions. In multi-family dwellings, they can also easily travel from unit to unit through walls, ceilings, floors, vents, plumbing and wiring. They also travel in on second-hand furniture and appliances. In rare instances, newly purchased items such as groceries can act as a carrier. While German cockroaches can survive outdoors temporarily, this is not common for prolonged periods of time. They only occasionally travel from one free-standing house to another.

How to Get Rid of German Roaches:

  • Keep your home clean and free of food scraps. Roaches thrive on food such as trash, dirty dishes, and leftover grease, as well as residues from toothbrushes and dish sponges. They can even survive through cannibalism, eating roach feces and exoskeletons. Good basic sanitation can not only prevent a roach infestation but also significantly improve the effectiveness of treatment.
  • Place bait traps where you most often see the roaches. The proper use of gel baits can often eradicate a German roach infestation. The key is place the bait in the specific spots within the room where roaches and/or their fecal pellets have been spotted. Near the coffee maker, on the floor by the stove, and on the wall behind the sink are common crevices where bait should be applied. Bait placements are ideally about the size of a pea.
  • Use caution when placing bait. Do not apply the bait to areas that come into contact with food, or that are accessible to children or pets.
  • Reapply bait to avoid re-infestation by new hatchlings. Re-bait three to four weeks after the initial treatment, to ensure that new roach hatchlings have fresh, palatable bait on which to feed and kill themselves.
  • Refer to a professional exterminator for faster treatment. A seasoned professional can usually eradicate a roach infestation faster than a homeowner by virtue of experience. German cockroaches are often elusive, reproduce quickly, and pose numerous health hazards. For these reasons, it is most effective to allow a professional to handle their extermination.

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