German Cockroach

How to Identify German Cockroaches

German cockroaches are small — 13 to 16 mm (about half an inch) as adults — and light brown to tan with two distinctive dark parallel stripes running from the back of the head to the base of the wings. Despite having wings, they rarely fly.

Nymphs (juveniles) are darker, sometimes nearly black, with the same two characteristic stripes visible on the abdomen. They are often mistaken for black beetles or unrelated insects. If you find a dark, small, fast-moving insect in your kitchen that has two stripe marks, it is almost certainly a German cockroach nymph.

German cockroaches produce an egg case (ootheca) that contains 30 to 40 eggs. The female carries this until shortly before hatching, when she deposits it in a sheltered harborage. Finding egg casings — small, brown, ridged capsules about 8 mm long — in cabinet hinges, behind appliances, or in drawer corners confirms an active infestation.

Behavior and Biology

German cockroaches are nocturnal and photophobic — they avoid light. If you turn on a kitchen light at night and see cockroaches, the infestation is large enough that they are being displaced from harborage by overcrowding. A single cockroach visible in daytime is a serious sign of a heavy infestation.

They prefer warm, humid environments within a few feet of food and water sources. The primary harborage sites are motor compartments in refrigerators and dishwashers, the void behind the dishwasher, under and behind the stove, inside cabinet hinges, and in wall voids near plumbing. In commercial kitchens, they concentrate in cooking equipment motors, under fryers, in grease traps, and inside electrical panels.

A German cockroach female produces 4 to 8 oothecae in her lifetime, each containing 30 to 40 eggs. With a gestation of 28 days and nymphs reaching adulthood in 6 to 12 weeks, a single pregnant female can theoretically produce thousands of descendents in a year.

Health Risks and Damage

German cockroaches contaminate food preparation surfaces with salmonella, E. coli, and other bacteria carried on their bodies from sewage and waste. Their droppings, shed skins, and body parts are potent allergens and are a documented trigger for asthma attacks, particularly in children. Studies in urban environments link cockroach allergen exposure to higher rates of emergency room asthma visits.

In commercial food service facilities, a German cockroach sighting during a Virginia Beach or Norfolk Health Department inspection is an immediate critical violation. A single confirmed cockroach can result in a required re-inspection within 48 hours and public posting of the violation status.

Prevention and Treatment

Store-bought sprays and roach bombs are largely ineffective against established German cockroach infestations. Aerosol sprays kill exposed roaches but do not penetrate harborage. Foggers scatter the population into walls where they are unreachable and can cause them to spread to previously unaffected areas.

Professional treatment uses gel bait applied directly into harborage sites — roaches consume the bait in their harborage and die there, and other colony members consume the dead and become affected (trophallactic toxicosis). This combined with an insect growth regulator (IGR) prevents nymphs from maturing to reproductive adults, breaking the breeding cycle.

For severe infestations, a flush treatment is applied first to drive roaches into open areas where they contact residual insecticide. Follow-up treatment is typically needed at 14 to 28 days. German cockroaches are covered under our standard residential pest control program and our commercial pest management program for food service facilities.