- Risk level
- High
- Peak season
- All year · peaks in warm, humid months
- Where you’ll find them
- Night-time; kitchens, bathrooms, drains, roof voids
- DIY?
- Hard — sprays scatter them
Overview
Cockroaches are one of the most common pest calls in Melbourne homes, rental properties and food businesses. A single German cockroach female can produce hundreds of offspring in her lifetime, which is why a few sightings can become an infestation in weeks.
How to identify cockroaches
German cockroach (Blattella germanica)
Small (12–15 mm), light brown with two dark stripes behind the head. Lives indoors around kitchens, fridges, dishwashers and electrical appliances. The hardest species to control.
American cockroach (Periplaneta americana)
Large (35–40 mm), reddish-brown. Lives in drains, sewers, sub-floors and roof voids, entering homes at night.
Australian cockroach (Periplaneta australasiae)
Large and dark with distinctive pale yellow margins on the wings and a yellow band on the thorax. Common in gardens, mulch and roof spaces.
Smoky brown cockroach (Periplaneta fuliginosa)
Uniform dark brown-black and glossy. Lives outdoors in mulch and enters through gaps and vents.
Signs you have a problem
- Live cockroaches when you turn on the light at night
- Droppings that look like ground pepper or coffee grounds in cupboards and drawers
- Brown egg cases (oothecae) behind appliances and in hinges
- A musty, oily smell in heavy infestations
- Dark smear marks along edges where they travel
Why it matters
- Carry bacteria such as Salmonella and E. coli onto food and preparation surfaces
- Shed skins and droppings are a recognised trigger for asthma and allergies, especially in children
- Can lead to a failed council food-safety inspection for food businesses
How we treat cockroaches
- 1
Inspection
We locate harbourage points — motor housings, hinges, cracks, drains and the roof void — so treatment goes where they actually live.
- 2
Gel baiting
Professional-grade gel baits are placed in cracks and crevices. Cockroaches share the bait, killing those hiding deep inside the nest.
- 3
Growth regulators & residual
An insect growth regulator (IGR) breaks the breeding cycle, with residual crack-and-crevice and sub-floor/roof void treatments where needed.
- 4
Follow-up
German cockroach jobs usually need a follow-up visit around two weeks later to catch newly hatched nymphs.
Prevention tips you can do today
- Wipe benches and sweep floors nightly; don’t leave dirty dishes or pet food out overnight
- Store pantry food in sealed containers
- Seal gaps around pipes, under sinks and behind splashbacks
- Fix leaking taps and keep under-sink cupboards dry
- Avoid bringing in second-hand appliances and cardboard boxes without checking them