There are many different types of cockroaches and most of them can spread disease. The three main types of cockroach in Australia are the German Cockroach, Australian Cockroach and the American Cockroach.
The Australian Cockroach is larger (30 to 35 mm) and is able to fly. It is dark brown with clearly defined yellow markings on the head and the front wings. This cockroach prefers plant food and is usually found outdoors. For example, under the bark of trees and among woodpiles.
The German Cockroach is one of the smallest of the cockroaches and can easily lead to infestations. Adults are 12 to 15 mm long, have a light amber/brown colour with two dark stripes on the head. German Cockroaches are mostly found in and around kitchens, pantries, storerooms and other food handling areas. They prefer to be near food, moisture and warmth. They do not fly.
The American Cockroach is one of the largest of the cockroaches (30 to 45 mm). It is red brown in colour with a pale yellow border around the head and it can fly. The American Cockroach prefers warm and moist conditions. It is a very widespread pest which lives in wall and roof cavities, sewers, drains, cellars, grease traps and rubbish dumps. It can be found around any food preparation area.
After mating, the female cockroach produces an egg case. This egg case can be either carried by the cockroach or left in a secure place until the young are due to hatch. When she is ready, the female cockroach leaves the egg case in a quiet, dark, warm location.
The eggs then hatch, these are called nymphs, they look much like a small version of an the adult. Cockroaches do not undergo a series of marked changes like flies and some other insects. Cockroach nymphs grow to adult size by a series of moulting processes.
In each of these, the nymph sheds its hard outer covering for a new, larger one. Depending on the type of cockroach it may take from one to twelve months for a nymph to grow to adult size.
Like flies, cockroaches can carry many disease-causing germs on and in their bodies. Because their natural homes include rubbish, dirt and filth they readily pick up germs from these areas. They then walk over food, cutlery, crockery and cooking equipment, benches, tables and other places in the home and pass the germs on to people.
Suggestions for Controlling Cockroaches
store food handling equipment and containers up off the floor
where possible, fill in small cracks and crevices (holes), in which cockroaches could hide. It is especially important to fill in cracks and crevices around pipes in walls
clean shelves and inside and underneath cupboards regularly. This will reduce the build-up of food particles