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.
Size: Adults about 1/2-5/8" (13-16 mm) long
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
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
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.)