German cockroach  Blattella germanica (Linnaeus)
Class: Insecta
Order: Blattodea
Family: Blattellidae

Size:German cockroach adults are about 1/2-5/8 in (13-16 mm) long.Characteristics: The German cockroach rarely glides or “flies”. Female’s abdomen is broader than that of male’s.Color: Light brown to tan with two alost parallel, dark longitudinal stripes, bars, or streaks on shield; female darker than male.

Where found: All over the world

Comparison with other species: Asian cockroach: similar color pattern, but flies readily, breeds outdoors in leaf litter, known in Florida. Brownbanded and Pennsylvania cockroaches: lack 2 dark longitudinal stripes. Field cockroach: dark line between eyes on front of head. Others: smaller or larger, lack stripes, and/or not in structures.

Habitat: German cockroaches may live throughout a building, but especially in warm and humid places, such as kitchens, bathrooms, and bedrooms and dens where people eat casually. They spend about 75% of their time hidden away in cracks and crevices. Smallest nymphs only need about a millimeter of space, while adults need about 5 mm.

Food: All types of food, as well as things like soap, glue and toothpaste.

Biology: Female carries egg capsule until within 1-2 days of hatching, and deposits it in a sheltered place. She will produce about 5 egg capsules (30-40 eggs each) in her life. Development from egg to adult varies, averaging about 3 months, but can be faster, resulting in 3-4 or more generations per year. Adults live about 3-7 months. Reproducing females are very active, but females carrying egg capsules are not, coming out for food and water only when necessary. Males hide, even at night. The last three days before molting, developing cockroaches (nymphs) stay hidden.

Damage: German cockroaches are the most common, and have the most impact as a nuisance. They may transmit disease organisms, and cause allergic reactions in some people.

Invasion: They come inside with paper products and packaging, and used appliances. In summer they may move from one building to another. They can survive outdoors if it is warm, although this is uncommon.

How to detect and control German cockroaches:

  • Inspect at night using a flushing agent and flashlight to determine species and location. Check drains.
  • Frequent treatment may be needed due to high rate of reproduction. For successful maintenance, 95% of the cockroaches must be eradicated during first treatment.
  • Baits are effective if placed correctly in cracks & crevices.
  • Initial pesticide application may include residual baits, insect growth regulators, liquids, aerosols, lacquers and/or microencapsulated pesticides, placed in cracks and crevices, occasionally on surfaces, or in voids. Dusting of voids is sometimes appropriate.
  • For control in sewers, dusting with silica gel is effective. Follow up with inspection, monitoring traps, and additional treatment if needed.