Cockroaches

Cockroaches are found all over the world. There are more than 4,600 species of cockroach of which 30 specie are associated with human habitat. Among the best-known pest species are the American cockroach, Periplaneta americana, which is about 30 mm long; the German cockroach, Blattella germanica, about 15 mm long; the Asian cockroach, Blattella asahinai, also about 15 mm in length; and the Oriental cockroach, Blatta orientalis, about 25 mm.

Because cockroaches eat a wide range of food, including rotting garbage, it is believed the cockroach may be a reservoir for a range of bacteria including salmonella, staphylococcus and streptococcus. The cockroach can also harbour viruses such as the polio virus.

Like the household fly, the cockroach will eat virtually anything ranging from food spills on a kitchen floor to faecal matter. Ingested bacteria can survive in the cockroach's digestive system, sometimes for months or even years, and are passed in its droppings. Cockroaches will vomit and defecate on food and it is thought that disease may be transmitted to humans when humans eat food contaminated by cockroaches.  Recent research suggests the cockroach may also be associated with human allergies.

A female cockroach lays between 10 and 40 eggs at a time, in an egg case called an oothecae. On average, the female can lay around 30 batches of eggs in her lifetime. The hatched young look the same as adult cockroaches, but smaller and without wings. Depending on the conditions and type, a cockroach can live for up to 12 months. These insects are cold-blooded and thrive in warm, humid conditions. This is why buildings in northern parts of Australia are particularly prone to infestations.

Some interesting facts:

§  The earliest cockroach-like fossils come from the Carboniferous period 354–295 million years ago

§  Recently genetic evidence suggests termites evolved from “true “cockroaches

§  Some species are capable of remaining active for a month without food and are able to survive on limited resources, such as the glue from the back of postage stamps

§  Cockroaches cannot survive more than a week without water

§  Some can go without air for 45 minutes

§  In an experiment, cockroaches were able to recover from being submerged underwater for 30mins

§  Japanese cockroach (P. japonica) nymphs, which hibernate in cold winters, survived twelve hours at -5 °C to -8 °C in laboratory experiments

Management tips to minimise activity:

§  Avoid leaving food-contaminated surfaces (benches, plates, dishes) overnight

§  Reduce water availability overnight, mop up puddles, fix dripping taps and seal around sinks

§  Store food in tightly closed, cockroach-proof containers

§  Inspect incoming food for egg cases

§  Store garbage in tightly closed containers

§  Fill cracks and crevices that can act as shelter

§  Inspect and clean surfaces below food processors and toasters

§  Clean ovens, cupboards and shelves