The cockroach is an unwelcome pest that infests Australian homes and gardens all year round and especially during summer. While not poisonous, cockroaches are classed as vermin because they can potentially spread disease. Keeping your kitchen and food preparation areas clean and clear of food spills, plus storing leftover food are important if you want to keep cockroaches at bay.
As cockroaches are nocturnal, they are most active at night and prefer dark, humid environments. The number one place you can expect to find cockroaches hanging out is in your kitchen as it’s a ready food source, with bathrooms coming a close second. Cracks and crevices in your wall, drains or open windows near the garden are common entry points by which cockroaches can infiltrate your home.
Worldwide there are more than 3,500 species of cockroach and around 400 of these live in Australia. Here the three most common varieties are the German, Oriental and American cockroach.
German Cockroach (Blattella germanica)
If you get surprised by a cockroach in your kitchen or bathroom, then it’s more than likely going to be a German cockroach. This is one of the most common cockroaches with a worldwide distribution. They measure around 1.2 – 1.5 cm in length and have two dark stripes on their pronotum (the small plate behind the head). In colour they are light brown or tan, and they prefer warm, humid conditions, preferably indoors.
Oriental Cockroach (Blatta orientalis)
A larger cockroach at 2 – 2.5 cm long and dark brown or even black in colour, the Oriental cockroach is commonly found in Australian homes and gardens. The female’s wings are short and non-functional so she runs rather than flies while the male’s wings cover most of the abdomen and can fly 2 – 3 metres. They prefer drains, basements, leaf litter and rubbish bins and feed on organic matter.
American Cockroach
The American cockroach loves warm climates preferably higher than 29C, which is why it thrives in places like Queensland and the Far North in summer. As the name suggests, it hails from the US but was originally introduced into there from Africa. In appearance it is quite large 3.5 – 4 cm long with a shiny red-brown body and a yellowish pronotum. It tends to run quickly when startled though is known to fly if it’s really hot. They like basements, kitchens, roof voids and bathrooms.
3 More Cockroaches Commonly Found in Australia
- Brown Banded Cockroach (Supella longipalpa) – 1 – 1.5 cm, yellow / cream stripes on abdomen,
- Australian Cockroach (Periplaneta australasiae) – approx. 3.5 cm, reddish brown body, long antennae and spiky legs,
- Smoky Brown Cockroach (Periplaneta fuliginosa) – 3 – 3.5 cm, shiny dark brown body.