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German CockroachGerman Cockroach

Order: Blattodae
Family: Blattellidae
Scientific Name: Blattella germanica (Linnaeus)
Color: Light brown to tan except for 2 dark, almost parallel longitudinal stripes/bars/streaks on pronotal shield. Female darker than male, her abdomen broader.
Legs: Six
Shape: Oval
Size: Adults about 1/2-5/8" (13-16 mm) long
Antennae: Yes
Flight: Rarely glide or "fly"

The German cockroach is by far the most important and usually the most common of the cockroaches. This species has worldwide distribution.

German cockroaches are found throughout structures but show a preference for warm (70 degrees F/21 degrees C) and humid places. They are usually found in kitchens and secondarily in bathrooms, but infestations often occur in rooms where people eat and drink while watching television such as the den, bedroom, etc. Any crack or crevice located near a source of food and/or water is prime harborage, and they spend about 75% of their time in such harborages. First instar nymphs require a crack of about 1/32" (1 mm) whereas, adults require a crack of about 3/16" (5 mm) in width.

The female carries her ootheca, or egg capsule, until it is within 1-2 days of hatching, and then deposits it in a sheltered area/site. On the average, the female will produce about 5 oothecae (range 4-8), averaging 30-40 eggs (range 18-50) each.

Developmental time (egg to adult) usually varies from 54-215 days, averaging about 103 days; under lab conditions of 80 degrees F/27 degrees C and 40% relative humidity, usually only 50-60 days are required. This means usually 3 to 4 generations per year, but up to 6. Adults live about 100-200 days (range 1-303). Established/mature German cockroach populations are typically composed of at least 75% nymphs.

These cockroaches are most commonly introduced into buildings via paper products or paper packaging such as grocery bags, cardboard boxes, drink cartons, and via secondhand appliances such as refrigerators, televisions, VCR's, microwaves, etc. They have been observed to migrate from building to building on warm evenings, but this rarely occurs. Although uncommon, they can survive outdoors during the warm months.

They feed on almost anything with nutritive value including all kinds of food, and such things as soap, glue, and toothpaste.

In addition to being a nuisance, it has been implicated in outbreaks of illness, the transmission of a variety of pathogenic organisms including at least one parasitic protozoan, and allergic reactions in many people.

Follow the standard control procedures but more frequent service may be required because of their rapid reproductive rate. At least 95% of the population must be eliminated on the initial service, or the typical maintenance program will usually fail. Baits are particularly effective, but correct placement along junctions and/or in cracks and crevices in or near harborages is essential. Incorporating IGRs (insect growth regulators) into the service helps with long-term control. Be sure to follow label directions.

(Source: National Pest Management Association, et. al.)