How to Identify, Prevent and Control German Cockroaches

German cockroach
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The German cockroach is one of the most common cockroaches to infest homes and food establishments. It is so small that it can squeeze between the tiniest of cracks to live behind the walls, appliances, etc. Following are some key facts about the German Cockroach and their babies.

What Adult German Roaches Look Like

The German cockroach adult:

  • is long and slender, about 1/2 to 5/8-inch long and 3/16 inch wide.
  • is light to medium brown in color.
  • has two short lengthwise stripes on its "pronotum"—the plate that covers part of the head in front and the base of the wings in back.

What Baby German Roaches Look Like

The German cockroach baby or "nymph":

  • is about the size of a typed period. 
  • begins in a round shape, changing as it grows into a teardrop then a cigar-like shape.
  • is dark brown with a small tan area on its back.

German Roaches vs. Asian Roaches

German and Asian cockroaches are so much alike, it is nearly impossible to visually differentiate them, but they are very different in behavior:

  • The Asian cockroach lives outdoors, the German indoors.
  • The Asian is attracted to light, the German prefers the dark and is rarely seen during the day.
  • The Asian can fly, the German cannot.
  • The Asian is found primarily in the southern U.S. and Japan, the German is nearly everywhere. 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. Its 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 (poop) pellets which look a lot like coffee grounds or ground pepper.

The German cockroach will also hide in 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

German roaches 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 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

  1. 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 will even eat the cast-off skins and feces of other roaches for survival. Good basic sanitation can not only prevent a roach infestation but also significantly improve the effectiveness of treatment.
  2. Place bait traps where you most often see the roaches. The proper use of gel baits can often eliminate a German cockroach infestation. The key is to 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.
  3. 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. Completely read and follow all label directions before using any bait or another pesticide.
  1. Reapply bait to avoid re-infestation by new nymphs. Re-bait three to four weeks after the initial treatment, to ensure that new roach hatchlings have fresh, edible bait on which to feed and kill themselves.
  2. Refer to a professional exterminator for faster treatment. A seasoned professional can usually get rid of a roach infestation faster than a homeowner because of their expertise and 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.