German cockroach or the big one?
| German cockroach | American cockroach | |
|---|---|---|
| Size and colour | 12 to 15 mm, amber, with two dark stripes lengthways | 35 to 40 mm, reddish brown, with a pale yellow border around the thorax (the section behind the head) |
| Where it lives | Kitchens, under sinks, in cupboards, drawers and appliances, near warm spots like water heaters | Roof, wall and subfloor spaces, sewers, grease traps and rubbish |
| How it arrives | As a stowaway in cardboard boxes or crates of food and drink | From drains and outdoor hiding spots |
| What it means | Breeding inside: worth a proper treatment | Often one wanderer; worth a look if you see several |
Signs you've got more than a visitor
With German cockroaches, look for droppings, small dark smears, cast skins and empty egg cases inside cupboards and around the fridge and dishwasher. Victoria's Health department says cockroaches seen out during the day often point to a large infestation.
The Australian Museum calls the German cockroach the hardest pest cockroach to get rid of. One female can produce up to 20,000 young a year, which is why a few in the kitchen is worth acting on rather than watching.
The WA side of a cockroach treatment
A registered business on the van
In WA, every vehicle used for pest treatments must show the business name and its Department of Health registration number, in letters at least 50 mm high. WA Health suggests asking for that number when you book.
Agree the plan first
WA Health suggests agreeing which areas get treated and which don't, any preparation such as clearing cupboards or sealing food, and what to cover or move, like toys and pet bowls.
Ask about the chemicals
It also suggests asking the technician to explain which products they'll use, why they suit the job, how they'll be applied, and any risks to pets, wildlife or sensitive people in the house.
If something goes wrong
Concerns about unregistered businesses or unsafe pesticide use go to WA Health. Overcharging or work left unfinished goes to Consumer Protection.
What helps, and what to leave to the technician
You can
- Clean behind and under the fridge, stove and dishwasher, where crumbs and grease build up.
- Store food, pet food included, in sealed containers.
- Fix dripping taps and leaks under the sink.
- Flatten and recycle cardboard boxes rather than storing them in the kitchen or pantry.
Leave to a pest business
- German cockroaches breeding in the kitchen or bathroom.
- Cockroaches in the roof, walls or subfloor.
- A follow-up visit to catch the ones that hatch after the first treatment.
Before you say yes
- Which cockroach is it, and where are they breeding?
- Is a follow-up visit included for German cockroaches?
- What should we clear out of the cupboards beforehand?
- When can we use the kitchen again, and is there a post-treatment report?
Our take on cockroach control in Perth
One big cockroach on the patio at night isn't worth a call-out. Small brown ones in the kitchen cupboards are: tap Cockroaches and say where you're seeing them.
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.
