How to Get Rid of Three Types of Cockroaches in Perth

What species of cockroach do you have?

Perth sees three main cockroach species, and they do not respond to the same treatment. The German cockroach (Blatella germanica) is small, tan with two dark stripes, 12 to 15 mm long, and lives in warm voids near food and water. The American cockroach (Periplaneta americana) is large, reddish-brown, 35 to 40 mm, and inhabits drains, sewers and sub-floors. The Australian cockroach (Periplaneta australasiae) is similar in size to the American with yellow edges on the wings and breeds outdoors in mulch, compost and wood piles.

A cockroach on a green leaf outdoors — A cockroach on a leaf outdoors.

Signs of cockroaches in your Perth home

Cockroaches leave evidence before you see them. Look for small dark droppings like coarse ground pepper inside cupboards and pantries. Brown smear marks along the top of cupboard doors, a musty smell in the pantry and egg cases behind appliances are warning signs.

German cockroaches congregate in kitchens and bathrooms near appliances, under sinks and in cupboard voids. American cockroaches prefer drains, sewers and sub-floor areas. Australian cockroaches usually live outside but will inhabit sub-floor, wall and roof voids when they come indoors.

Why cockroaches thrive in Perth

Cockroaches are attracted to warm, humid, undisturbed areas with access to food and water. Perth's mild winters mean there is no seasonal die-off. Autumn is when they move indoors. German cockroaches are most common in kitchens near appliances and water sources. American cockroaches live indoors in cool regions and outdoors in warm regions, commonly infesting buildings in both situations. Australian cockroaches usually live outside in greenhouses, shrubs, trees, woodpiles and under leaf litter, and sometimes come indoors.

What you can do yourself to reduce cockroaches

Good hygiene is the foundation of any cockroach program. Clean the house thoroughly, paying special attention to the kitchen and areas around the fridge, stove and dishwasher. Empty the rubbish bin regularly and do not leave out pet food or food scraps in pet bowls. Store all food in sealed airtight containers and wipe up spills immediately. Cockroaches need water to survive, so fix dripping taps, leaking dishwasher hoses and any other sources of standing water. Remove clutter, do not stack newspapers and cardboard boxes.

Reduce harbourage by sealing cracks and crevices in skirting boards, cupboards and around pipes. Clear vegetation away from the perimeter and do not stack wood or garden waste against the walls. Keep compost bins screened and away from the house. Sticky traps placed in the kitchen or under appliances can help you monitor activity over time.

Do not spray or bomb the kitchen beforehand. Repellent aerosols scatter cockroaches away from the gel and hide the harbourages that need to be treated. If you have already sprayed, get it checked by a licensed technician before you try anything else.

When to call a professional for cockroach treatment

When DIY measures do not work or the infestation is already established, professional treatment is the most effective option. We identify the species and the harbourages with a torch and a flushing agent, then treat it to plan. German cockroach jobs use gel bait and an insect growth regulator placed inside cabinetry voids, behind and under appliances, away from food-contact surfaces. An insect growth regulator stops juveniles maturing into breeding adults. American and Australian cockroach jobs focus on drain treatment and penetrations, plus external harbourage cleanup and a perimeter residual. All work is applied to label by a technician holding a WA pest management technician's licence (Health (Pesticides) Regulations 2011).

Established German infestations get a scheduled follow-up visit, which is included in the kitchen program. Every job is quoted itemised in writing before we book. You get a copy of the treatment record with every job. If cockroaches named on your invoice are still active inside the treated areas within the six-month promise period (terms at djpest.com.au/warranty), we return at no charge.

To book a cockroach treatment, use the cockroach control service page or text your suburb and what you're seeing to 0468 170 107. If you have German cockroaches specifically, the German cockroach guide covers treatment in more detail.

What cockroach treatment costs in Perth

A German cockroach kitchen program, including gel, growth regulator, targeted residual and a follow-up visit, typically runs $250 to $450. Light cockroach activity covered within a general pest treatment costs $250 to $350. This is a typical range for a standard home in Perth's northern suburbs, itemised in writing after we have seen it. Drain treatment for American cockroaches and external harbourage cleanup for Australian cockroaches are quoted after inspection. See the investment guide for full pricing on all pest treatments.

Frequently asked

Can I treat cockroaches myself with shop-bought products?

Spray kills the cockroaches you see walking. The rest are inside voids, behind appliances and inside egg cases, and they breed back faster than survivors die. Gel bait reaches the ones in the voids, and an insect growth regulator stops juveniles maturing into breeding adults. A proper treatment combines inspection, gel placement, growth regulator and follow-up. The spray is the smallest part.

How long does cockroach treatment take to work?

German cockroach activity usually falls away over two to three weeks as the gel and growth regulator work through the population. Drain-based American and Australian jobs clear faster because we can treat the breeding site directly. Established German infestations get a scheduled follow-up visit included in the kitchen program.

Are gel baits placed near food or on benches?

Gel is placed inside cabinetry voids, behind and under appliances, on the hinge side of doors and in kickboard gaps, away from food-contact surfaces. We do not spray inside kitchen cupboards or on benches. You get a list of placements with your report.

What about cockroaches in apartments and units?

German cockroaches move between units through shared walls and plumbing. If only your unit is treated, re-infestation from next door is likely. Strata-coordinated treatment is the best outcome. Failing that, we treat your unit thoroughly, seal the penetrations we can reach and set expectations honestly.

Do cockroaches spread disease?

Cockroaches walk through drains and refuse, then across food-preparation surfaces, carrying bacteria like salmonella with them. Their droppings and shed skins are a recognised asthma trigger. That is why food businesses run continuous cockroach programs and why we treat the breeding sites, not just the visible adults.

What is an insect growth regulator and why do you use it?

An insect growth regulator stops juvenile cockroaches maturing into breeding adults. One female German cockroach produces dozens of offspring per egg case and can produce multiple egg cases throughout her breeding period.

What should I do to prepare for a cockroach treatment?

Empty the cupboards under the sink and next to the stove. Pull the fridge and dishwasher out if you can do so safely; otherwise we will. Clear benches, put away food and pet bowls, and empty the bin. Do not spray or bomb the kitchen beforehand. Tell us about anyone in the home with asthma or chemical sensitivity so we can adjust the plan.

What is the re-entry period after cockroach treatment?

Kids and pets stay out of treated rooms until surfaces are dry and the re-entry period we advise has passed. We tell you the exact re-entry period on your treatment record when we arrive.

Sources

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