German, Oriental and American Cockroaches
![]() |
![]() |
![]() |
German Cockroach |
Oriental Cockroach |
American Cockroach |
Cockroaches carry a range of bacteria, causing allergies and disease. The German Cockroach is often found in food preparation areas.
They live in warm areas such as around dishwashers, ovens, fridges and hot water systems. They are very small in size and are a light colour.
Their eggs are often transported in cardboard boxes.
Cockroaches hide in many areas around premises, including:
- Cracks in walls.
- Confined spaces, such as behind the refrigerator or underneath a stack of magazines or cardboard boxes.
- Any furniture items that are generally left undisturbed.
- Kitchen cupboards.
- Below sinks.
- Around water heaters.
- In drains and grease traps.
- Gardens.
Steps to prevent or eliminate cockroaches include:
- Clean thoroughly, paying special attention to the kitchen and other food preparation areas.
- Clean regularly underneath the fridge, stove, toaster and other movable appliances.
- Empty the kitchen's rubbish bin regularly.
- Clean up any food spills promptly.
- Make sure there are no sources of water, such as a dripping tap, since cockroaches need a steady water supply to survive.
- Store food in containers with tight fitting lids.
- Repair any holes, cracks or gaps in the walls, skirting boards and inside cupboards.
- Dont stack newspapers, magazines or cardboard boxes anywhere around the property.
- Keep compost bins screened and away from the house.
- Maintain the garden regularly.
- Use appropriate insecticide and follow the manufacturer's instructions exactly.
- Use traps, such as greased margarine tubs containing a smear of honey as the lure - cockroaches will climb in for the food, but be unable to get out because of the grease (or oil) on the tub.
- Use commercial pest control contractors.
German cockroachThe German cockroach is the most common cockroach found in houses and apartments in Australia. Their small size means that human occupants, many of whom do not recognise early nymphal stages as cockroaches, initially tolerate them. Their rapid reproduction rate enables a few individuals to become a pest problem over one season. From an original female German cockroach there could be potentially more than 100,000 cockroaches in a home by the end of one year!
German cockroaches are nocturnal and forage for food and water at night when they are less likely to be seen. In the daytime, they hide in cracks and crevices in cupboards and kitchen appliances and so are easily overlooked. You can find them then around refrigerators, dishwashers, stoves, washers and dryers, and water heaters. They do not fly.
The German cockroach is the most difficult pest cockroach species to control
The oriental cockroach
The oriental cockroach is found in the cooler areas of Australia. They are dark brown or black and may be found under floors, in sewers and drains, and around garden rubbish.
A single female oriental cockroach has a much lower potential for producing offspring than either the German or the brown-banded females. They are more sensitive to lack of water than other cockroaches and like cool, damp locations. Look for oriental cockroaches in dark, damp basements, crawl spaces, areas between soil and the foundation, underneath sidewalks, in sewer pipes, floor drains and any other cool, moist place. Outside, they sometimes aggregate near or under garbage cans.
American cockroach
The American cockroach is the largest of the pest species. It is red-brown, with fully developed wings that cover the abdomen, and it will fly in warm conditions. The American Cockroach has a great potential for producing offspring.
Because of the large size of both adults and nymphs, people are less tolerant of this species, and the cockroaches also find fewer places inside to hide in the daytime. When established in homes they are normally found in wall voids or behind cupboards, in underfloor areas or in roof spaces.
Normally they enter living rooms, kitchens and bathrooms when they are foraging for food and water. They are most associated with the areas around homes or buildings. Common areas where they are found include gardens, around garbage, inside drains and in outhouses such as sheds or garages.
American cockroaches can coexist with German Cockroaches with no negative effects on either cockroach population.
| Further Information available from the City of Holdfast in Adelaide fact sheet on Cockroaches – American and German. Click on image below to further information. | Information taken from Bayer Healthcare – Insects and Spiders. Click on image below for further information. |


