Cockroaches

Cockroaches have changed little during the 400 million years they have been around. Most species are of tropical or sub-tropical origin. Although they are not social insects, they are gregarious or commonly occur in groups. They will feed on practically anything of nutritive value.

Cockroaches are among the most important pest of households and commercial premises. Not only is their mere presence a nuisance but they are known to be capable of carrying many common disease pathogens as well as causing allergic reactions in many people.

Of the approximately 4,000 living species of cockroaches in the world, about 70 occur in Australia. Only a few of these cockroach species inhabit man's dwellings. The more common are the Australian, American, German and the Smoky brown cockroach species. By far, the most common is the German cockroach.

Identification:

It is advisable to know the cockroach species being encountered because cockroaches vary in their food preferences and living habits. For example American cockroach prefer living in food storage areas, voids in roofs, walls and subfloor areas. German cockroach live in cracks and crevices and very tight spaces very close to water in kitchens, bathrooms and laundry. Because they are relatively small they are able to live inside appliances such as microwaves, telephones, clock-radios, videos records and computers.

Biology:

Cockroaches have incomplete or simple metamorphosis: egg, nymph, adult. Nymphs and adults are similar in appearance expect for size and and the presence of wings on adults.

Appearance and Habits:

Characteristically. all cockroaches have a flattened body and small head that is protected by a shield-like structure known as the pronotum. At rest, the wings lie flat over the body with the hardened fore-wings protecting the more delicate hind wings. The various species are distinguished by their size, and variations in the colour patterns on the pronotum. All domestic cockroaches are nocturnal, hiding during the day in crack, crevices and under litter. At night, the feed on a wide range of foods, particularly those with a high carbohydrate content. Most human food stuffs, woolen and leather goods, books and papers are all typical high carbohydrate food items found in homes and commercial buildings and are all attractive food for cockroaches. Large numbers of cockroaches leave a characteristic 'roachy' smell and may also taint foods. Food may also become contaminated from the droppings and bacteria found with these insects. Their association with garbage, sewers and toilets has linked them with the spread of a variety of human diseases, including tuberculosis, cholera, leprosy, dysentery and typhoid.

Control:

Good hygiene is most important in keeping cockroaches at a low to insignificant level. Pay particular attention to preventing the cockroaches' access to a food source, and so minimise breeding.

Accumulating food scraps, and spills around stoves, cooking areas and sinks should be avoided. Stored food should be kept in air-tight containers.

Cracks and crevices in floors and walls are potential hiding places and food traps. These should filled or cleaned regularly.

Cockroaches can never be completely eradicated as a reinfestation can easily occur.