How to Get Rid of Cockroaches in Brisbane Homes

German or Australian cockroaches

Identification changes the whole treatment. These are three common house cockroaches in South East Queensland.

German cockroach

German cockroaches are small, around 12 to 15 millimetres long as adults, and light brown. The giveaway is two dark stripes running along the shield behind the head. Museums Victoria describes them as living in warm, dark, moist spots, including cracks and crevices in kitchens.

Look around the fridge motor, dishwasher, cupboard hinges and under the sink. They live and breed inside.

Australian cockroach

Australian cockroaches are a lot bigger, roughly 23 to 35 millimetres long, and brown with a pale yellow edge along the front of the wings and yellow markings behind the head. The University of Florida's entomology department notes they do well outdoors. Around here that means garden beds, mulch and woodpiles, and they come inside at night.

American cockroach

The American cockroach is the big reddish brown one, up to about 54 millimetres long according to the University of Florida, with pale markings behind the head. It likes drains, sewers, sub floors and roof voids.

The large outdoor species are a nuisance. German cockroaches are the ones that turn into a real infestation, because their whole life cycle happens inside your kitchen.

What attracts cockroaches

Cockroaches want food, water and somewhere warm and tight to hide. A Brisbane summer supplies the heat, so the rest comes down to the house:

• crumbs and grease around the stove, toaster and under appliances
• pet food left in bowls overnight
• leaking taps, dripping pipes under the sink, and damp bathrooms
• cardboard boxes and paper stored in cupboards, garages and under beds
• thick mulch and leaf litter against the walls of the house

Where do cockroaches come from?

German cockroaches usually hitch a ride in with you, in boxes, second hand appliances, furniture and bags. Australian and American cockroaches walk in from outside, through gaps under doors, weep holes, drains and around plumbing.

Finding egg cases

Egg cases tell you how established the problem is. Every species lays its eggs inside a hard capsule called an ootheca.

What do cockroach eggs look like?

Cockroach egg cases are small, brown, purse shaped capsules with a ridged seam along one edge. German cockroach egg cases are light brown and under a centimetre long. The bigger species produce darker, chunkier ones.

The German cockroach female carries her egg case attached to her body until the eggs are almost ready to hatch, rather than dropping it early. That protects the eggs from sprays and is one reason German cockroach numbers climb so fast. Australian and American cockroaches drop or glue their egg cases in sheltered spots like cupboard corners, sub floors and behind furniture.

Finding egg cases, shed skins and pepper like droppings in cupboard hinges or behind appliances tells me where the colony is centred.

Home fixes that actually help

You can make a real dent in numbers yourself, especially with the outdoor species. Start here.

1. Clean under and behind the fridge, stove and dishwasher. Grease build up feeds them for weeks.
2. Fix leaks under sinks and around the laundry. Water is often harder for them to find than food.
3. Store food, including pet food, in sealed containers and don't leave bowls out overnight.
4. Get rid of cardboard. Use plastic tubs in the pantry and garage instead.
5. Seal gaps around pipes under sinks, and fit door seals on external doors.
6. Pull mulch and leaf litter back from the walls of the house.
7. Use gel baits from the supermarket in small dots where you see activity, and don't spray near them.

How to prevent cockroaches coming back

Keep up the habits above. Wipe benches every night, take the rubbish out and watch dark, damp spots. A regular professional treatment reaches the places you can't.

What smell do cockroaches hate?

You'll see claims online about bay leaves, peppermint oil, cucumber and vinegar. Some of these may make a spot less attractive for a short time, but a smell won't remove a colony that is already breeding behind your fridge.

Why sprays alone fail

A spray only kills the cockroaches it touches. Most of the colony is hidden inside walls, appliances and cupboard joints. The eggs are protected inside the egg case, which the female carries until they're ready to hatch, so a fresh lot of nymphs turns up a few weeks later. Spraying near baits also makes the bait less attractive, so you undo your own work.

German cockroaches have also built up resistance to many common insecticides, so a mix of methods matters. Bait in the right spots plus a follow up visit to catch the next hatch is what works.

How to eliminate German cockroaches

Clean first, bait in small amounts close to where they hide, and keep sprays away from the bait. If numbers aren't dropping after a couple of weeks, get professional help.

How to get rid of Australian cockroaches

The Australian cockroach lives outside, so focus there. Clear mulch and leaf litter from the walls, seal gaps around doors and pipes, and fix outdoor lights that attract insects to entry points. An external perimeter treatment around the house deals with the areas they move through.

When to call a professional

Call a professional if you're seeing German cockroaches during the day, which usually means a large population. Call too if it keeps coming back after a few weeks of baiting.

When I do cockroach control, I start by finding where they're living, which is often a long way from where you've seen them. Then I bait and treat the right spots inside, and treat the external areas they use to get in. It's part of my wider general pest control service, which comes with a 12-month internal service warranty. I do every job myself and I'm fully licensed and insured, QBCC licence 15076438.

So, to sum up how to get rid of cockroaches in Australia: work out the species, take away their food, water and hiding spots, bait rather than spray for German cockroaches, and seal the house against the outdoor ones. If you want it done properly, request a quote or call me on 0412 205 586.

Summary: how to get rid of cockroaches in Australian homes

• Small, striped roaches in the kitchen are usually German cockroaches and breed indoors.
• Large brown roaches are usually Australian or American cockroaches coming from outside.
• Food, water and clutter attract cockroaches. Remove them first.
• Sprays alone don't reach the colony or the eggs. Baits and follow up work better.
• Call a professional if German cockroaches are out in daylight or keep coming back.

Frequently asked questions