German cockroach (Blattella germanica)
The German cockroach is about 5/8-inch in length, brown in color, with two dark longitudinal streaks on the pronotum. The male is light brown and somewhat boat-shaped. The female is slightly darker in color with a broader and rounded posterior. Nymphs are similar in appearance to the adults but wingless with 2 dark bands running halfway down their back. Nymphs range in size from 1/8 to 1/2 inch in length.
It is the most prevalent species in and around homes, apartments, supermarkets, food processing plants, and restaurants. Ships, especially cruise ships and naval vessels, can also be heavily infested. During the day in houses, they hide in cracks and crevices such as under kitchen appliances, sinks cabinets, behind baseboards and moldings, in wall voids, pantries and similar areas of homes and restaurants. In commercial establishments such as food plants, warehouses, supermarkets, etc, they can be found in cardboard containers, wooden boxes, and under pallets.
The German cockroach breeds throughout the year indoors, but favors a humid environment and an average temperature of approximately 80° F. A life cycle can be completed in about 3 months. The German cockroach produces more eggs per capsule than other pest cockroach species, and its young complete their growth in a shorter period of time. Female German cockroaches carry their egg capsules until they are ready to hatch. The number of eggs in a capsule usually is between 30-40, with a maximum of 48. The average number of nymphs hatching is 30. The average incubation period at 76° F was 28.4 days. Capsules removed from the female do not usually hatch. Females at room temperature may produce an average of 4-5 capsules in her life time.
The time for nymphs to mature to adults averages 103 (54-215) days. They progress through 6-7 nymphal instars in 60 days for males and 65 days for the females. Females may live for more than 200 days.
The German cockroach is spread by commerce and transportation, as well as by its migrations. Many homes and business establishments become infested with German cockroaches when they are introduced in infested cartons, foodstuffs, and other materials. The German cockroach appears to be extending its range into nontraditional sites in buildings due to the availability of water in many areas. Plants are often located throughout the house or workplace, drinks are often carried or left anywhere, consequently German cockroaches are able to get sufficient moisture and food to survive.
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