Cockroaches in Brisbane
The subtropics suit the big ones
Victoria's health department says Australian cockroaches are most common in warm subtropical to tropical places. They usually live outside around shrubs and trees, and sometimes move into the subfloor, walls and roof.
American cockroaches live outdoors here
In cool regions American cockroaches live indoors, but in warm places like Brisbane they live outside, around sewers, grease traps and rubbish, and come in from there.
Smokybrowns can fly
The smokybrown cockroach, about 30 mm and shiny dark brown, can fly short distances in warm weather. It turns up in sheds, mulch, drains and roof voids.
Damp after summer storms
Most of South East Queensland's rain falls in summer and autumn. Blocked drains, leaking taps and wet mulch against the walls give cockroaches the moisture they look for.
German cockroach, or one of the big ones?
| German cockroach | American, Australian, smokybrown | |
|---|---|---|
| Size | 12 to 15 mm, amber with two dark stripes | About 30 to 40 mm, reddish to dark brown |
| Lives | Indoors: kitchen cupboards, under sinks, inside appliances | Mostly outside: garden, drains, subfloor, roof |
| How it arrives | As a stowaway in cardboard boxes and food crates | Walks or flies in from outside |
| Seen in daylight? | A warning sign of a large population | Common on warm nights, near doors and drains |
| The job | Indoor baiting, close inspection and follow-up visits | Treatment outside, in the subfloor and roof, plus sealing gaps |
Why German cockroaches take longer
The Australian Museum calls the German cockroach the hardest pest cockroach to get rid of. Females carry their egg cases around with them, each holding 30 to 48 eggs, so a treatment that reaches the adults can still leave a new generation on the way.
That's why a German cockroach job usually means baits placed into hinges, cracks and appliance gaps, a close look behind the fridge and stove, and at least one follow-up visit. The job is bigger in a unit block, where cockroaches move between kitchens, or when appliances and cupboards are packed tight.
Cockroaches can also trigger strong allergic reactions in some people, so mention asthma or allergies in the house when the technician calls.
What you can do
You can
- Clean grease and crumbs from behind the stove, toaster and fridge.
- Keep food sealed and take rubbish out at night.
- Fix dripping taps and leaks under the sink.
- Unpack delivery boxes outside, then get the cardboard out of the house.
- Keep mulch and leaf litter back from the walls and drains.
Leave to a pest business
- Baiting inside cupboards, appliance voids and wall gaps.
- Treating the subfloor, roof space and outside walls.
- Follow-up visits to check whether the population is falling.
Before the treatment
- Which cockroach is it, and what does that change about the job?
- Which products will you use, and can I have their full names?
- Do we need to empty the kitchen cupboards first?
- When should we see fewer, and when is the follow-up?
If it were our house in Brisbane
One big cockroach on a warm night is the garden paying a visit, not a reason for a treatment. Small ones in the kitchen, especially in daylight, are worth acting on quickly: tap Cockroaches and say which kind.
Want someone to look at it?
Tell us what you've seen and your postcode, and a local pest business that handles exactly that calls you to talk it through.
