Major pest species
German cockroaches are amber in colour, 12-15 millimetres long when fully grown, with two dark longitudinal stripes. They are the most prolific breeder of the pest cockroaches; German cockroaches will eat almost any organic material, ranging from crumbs to built-up grease. German cockroaches congregate in warm, undisturbed areas of high humidity. Most infestations are found in kitchens. Cockroaches may be found under sinks, in and under cupboards and drawers, and around electrical equipment such as refrigerators. They hide in cracks and crevices during the day and feed at night. Sightings in other areas of the house, for example bedrooms, may indicate a large infestation.
American cockroaches are the largest common pest species of cockroach, reaching 35-40 millimetres in length. They are reddish-brown in colour with a pale yellow border around the upper part of the thorax and pale legs. American cockroaches are capable of flying short distances in warm conditions. American cockroaches prefer to feed on decaying organic matter, but will eat most other organic foods, including paper and clothing (particularly if soiled). Their desire for fermented liquids, such as beer, is very strong. They will often travel for food, but adults with a water source can survive for 2-3 months without it. American cockroaches usually congregate in warm, moist, dark locations. They prefer coastal areas, but are a widespread pest, living indoors in cool regions, and outdoors in warm regions. Buildings commonly infested include hospitals, bakeries, food stores, factories and houses. They tend not to infest dwelling areas in buildings, but rather the roof, wall and subfloor areas, and in and around sewers, grease traps and rubbish dumps.
These are darkish-brown cockroaches, about 35 millimetres long with yellow markings on the upper part of the thorax and on the fore margins of the forewings. Australian cockroaches are most commonly found in warm sub-tropical to tropical environments and usually live outside in greenhouses, in and around shrubs and trees, around woodpiles and under bark or leaf litter in gardens. They sometimes come indoors and will inhabit subfloor, wall and roof voids. They prefer food of plant origin, becoming a pest when they enter homes and eat holes in clothing and books. Residual barrier sprays can substantially reduce Australian cockroach populations around houses.