Cockroaches in Perth, Australia

When it comes to pests, there may be no home intruder more unwelcome than the cockroach. While rodents, fungal colonies, and various insects can make life unsafe and uncomfortable, there is just something about cockroaches that causes them to be viewed with almost universal disdain.

With their ability to rapidly infest an area, their tendency to prefer the same types of habitats favored by humans, and their reputation for being seemingly indestructible, they can be a real challenge for pest control efforts. To effectively cope with these creatures, it is important to understand as much as we can about what they are and how their presence can be prevented.

Reviewed by Robert Luckens, long-standing pest control expert at Rockypest.

Ancient Origins

Scientists tell us that cockroaches are among the most ancient of insect species, and there is evidence that they have been around at least 300 million years. That means, of course, that they not only predate the dinosaurs by roughly 70 million years, but also survived whatever extinction-level event caused those giant lizards to disappear from history.

Various archeological finds have confirmed that those ancient cockroaches were extremely adaptable – a trait shared by their descendants today.

What Exactly is a Cockroach?

Cockroaches are insects that are classified within the same order as termites, and are considered one of the more primitive insects in existence today. They are considered to be generalized insects, having developed none of the more specialized traits seen in many other insect species. That generalized nature also helps to make them extremely adaptable to a wide variety of environments around the world.

Cockroaches are considered a social species of insect, and tend to gather in groups in an exhibition of what scientists refer to as swarm behavior. Infestations that begin with a single cockroach can grow larger as others of their kind follow their fecal trails in an attempt to discover new food and water sources. Those fecal trails often contain pheromones that the insects use to identify different roach populations.

Scientists have extensively studied this social behavior and discovered that populations of roaches appear to make decisions in a collective manner, apparently cooperating in complex ways to ensure that they organize themselves in a way that enables sustained exploitation of available resources.

Related → Cockroach Behaviour | On the Trail of the Cockroach

Quick Facts About the Roach

• Most roach species are winged, and they all have oval bodies that are relatively flat. Their heads contain antennae, and a mouth that chews in the same way many other scavengers consume food. Their legs have evolved in a way that facilitates surprisingly rapid movement, acceleration, and rapid turning.
• Roaches are nocturnal in nature, preferring to hide within cracks during daylight hours.
• There are some 4,000 species of cockroaches on the planet, with most of them found in warmer environments. They are a hardy species, however, and exist in virtually every climate – including the arctic and desert regions of the world.
• Most cockroaches are not pests and instead fulfill an important role in nature. In fact, only a few dozen species are actually considered to be pests.
• Cockroaches are omnivores, meaning that they will consume just about anything they find. While they gravitate toward sweetened food sources, they are capable of surviving on everything from leather and glue to grease, hair, and soap.
• That incredible ability to survive on just about any item it eats is due to the cockroach’s complex relationship with certain symbiotic bacteria that exist within their fatty tissue. These bacteroides are present at birth within each cockroach, and manufacture nutrients such as amino acids and vitamins for the host, enabling roaches to eat even nutrient-free items.

Related → Getting Rid of Cockroaches: What Do They Eat?

What Makes Them Pests

Cockroaches are considered pests for a number of reasons, primarily related to their potential for destruction, contamination of food, spreading of illness, and potential for causing allergic reactions in some people.

Running a food business? The same contamination risks apply on a bigger scale in cafés, restaurants and commercial kitchens, where grease traps, warm equipment and constant food supply suit cockroaches perfectly.

Related → Reduce the Risk of Foodborne Illness at Your Restaurant | Commercial Pest Management

Problematic Roaches in Australia

Among the several dozen roach varieties that are deemed pests, only a handful are considered pests in Australia, and only three qualify as truly common infestation threats – the German, American, and Oriental cockroach. Each has its own particular nuisance potential, its own living habits, and its own unique appearance.

What Perth homeowners actually find: alongside those three, the Australian cockroach is a very common find around Perth and the Peel region, especially in gardens, subfloors and wall cavities during the warmer months. Each species below includes a quick ID panel covering size, whether it flies, and where it tends to turn up in a Perth home.

The American Cockroach

The American cockroach typically runs along the ground at high speeds, but can fly when they temperature is hot enough. This is one of the larger varieties of roach, reaching sizes as long as 40mm. The roach is identifiable by its shiny, reddish-brown coloring.

In their natural habitat, they are generally found in trees and referred to as the Palmetto bug. When they make their way indoors, they seek out damp, dark areas such as basements, bathrooms, kitchens, and subfloors.

Quick ID: the biggest pest roach in Perth homes, up to 40mm, shiny reddish-brown with a pale yellowish edge around the shield behind the head. Flies? Yes, short flights and glides on hot nights. Where in Perth homes: drains, sewers, subfloors, bathrooms and roof voids.

The Oriental Cockroach

These dark brown roaches can grow to be as much as 25mm in length, and are one of the more adaptable species on the planet. They thrive in damp locations, preferring cool temperatures like those found in basements and drains.

They are also routinely found around garbage cans, since they seek out trash and decayed matter as their preferred food source. Because their wings are underdeveloped, they run instead of flying.

Quick ID: glossy dark brown to almost black, up to 25mm and slow moving. Males have short wings and females have only small wing stubs. Flies? No. Where in Perth homes: drains, laundries, crawl spaces, under pavers and around bins, particularly in older and coastal properties.

The German Cockroach

These cockroaches are found across the world, and are most commonly seen inside buildings and homes rather than outdoors. Growing to as long as 15mm, they can be identified by two dark stripes that run along the pronotum plate that covers the dorsal section of the thorax.

They are fairly prolific breeders, producing as many as 4 generations in a single year. Their chosen habitat is one in which the conditions are both wet and humid – which is why they are commonly found in bathrooms, kitchens, and commercial or industrial locations.

Quick ID: small, light brown to tan, up to 15mm, with two dark stripes behind the head. Flies? It has wings but rarely uses them. Where in Perth homes: warm, moist gaps behind fridges, dishwashers, kettles and microwaves, and inside kitchen cupboard hinges. The female carries her egg case until it is almost ready to hatch, which is one reason surface sprays so often miss the next generation.

Related → Cockroaches in Your Home: How to Get Rid of Roaches

The Brown-Banded Cockroach

This aptly named roach is fairly small, typically growing to only 10 or 15mm in length, and has antennae that are about the same size as their body. They are distinguished from other varieties by the yellowish brown stipes that run along their abdomen region.

The brown banded roach usually remains grounded, seeking out safe habitats in heated structures. Since they are nocturnal, they typically look for attics, crawl spaces, or false ceilings where they can conceal themselves throughout the day. Their preferred food source consists of anything with a high level of starch.

Quick ID: one of the smallest pest roaches, 10 to 15mm, with two pale bands across the body. Flies? Mostly no, although adult males can make short flights in hot conditions. Where in Perth homes: unlike most roaches it tolerates drier spots, so check high cupboards, behind picture frames, inside electrical appliances and in ceilings.

The Australian Cockroach

Many Australians are familiar with this pest, though many may not be aware that its name is something of a misnomer. In fact, the Australian cockroach is not even a native roach species! It has, however, made itself right at home throughout the country, especially in temperate areas with plenty of human habitats.

This roach can grow to be as long as 35 mm, making it one of the larger varieties of cockroach pests.

Quick ID: dark reddish-brown, up to 35mm, with pale yellow edges on the front of the wings and a yellow-rimmed shield behind the head. It looks like a slightly smaller American cockroach. Flies? Yes, it is a capable flier in warm weather and is often drawn to lights. Where in Perth homes: garden beds, mulch, leaf litter, subfloors and wall cavities, coming inside in search of food and moisture.

Smoky Brown Cockroach

The smoky brown cockroach can be as long as 35 mm, and has a shiny dark brown color. Like many of its cousins, it prefers to run along the ground, but can fly in areas with high temperatures.

Outdoors, it is found in the hollows of trees and under tree bark. It often finds its way into buildings at night, where it leaves it saliva and excrement in food sources, contaminating them with illness-causing bacteria.

Quick ID: uniformly dark, shiny mahogany-brown, up to 35mm, with none of the pale markings seen on American and Australian roaches. Flies? Yes, in hot weather, and it is strongly attracted to lights. Where in Perth homes: roof voids, eaves, tree hollows and under bark close to the house.

Related → Common Australian Cockroach Pest Types You Should Know

Cockroach Size Guide: How Big Do Cockroaches Get in Australia?

If you have just spotted a roach and want to know what it is, size is the quickest place to start. The grid below pulls together the sizes described above so you can compare the six pest species at a glance.

Small cockroaches: a tan roach around 10 to 15mm, especially inside kitchen cupboards or near appliances, is most likely a German or brown-banded cockroach. These species breed indoors, so a few small roaches is usually a bigger worry than one large one.

Large cockroaches: a big roach of 25 to 40mm is usually an American, Australian, smoky brown or Oriental cockroach. These larger species often live outside in gardens, drains and roof voids and wander in, particularly on warm nights.

One catch: young cockroaches (nymphs) of the big species are small and wingless, so a small roach is not always a German cockroach. If you are unsure, a technician can confirm the species on inspection.

Do Cockroaches Fly in Australia?

Yes, some do. Most pest cockroaches have wings, but only a few species use them well. Around Perth, the ones most likely to fly are the American, Australian and smoky brown cockroach, and they mostly do it on hot, humid nights.

Much of what people describe as a flying cockroach is really a short flight or glide from a wall, fence or tree toward a light. The German cockroach has full wings but rarely flies, and the Oriental cockroach cannot fly at all.

Why they seem to appear in summer: warmth lifts cockroach activity, so outdoor species leave their hiding spots at night to forage. Porch lights, open doors and gaps in flyscreens then draw them toward the house.

Native Bush Cockroaches: Should You Worry?

Not every cockroach in Perth is a pest. Australia has hundreds of native cockroach species living in bushland, leaf litter and gardens, where they help break down plant material.

Around Perth, one you may notice is the bush cockroach (Ellipsidion humerale), a small, harmless native with distinctive yellow and dark markings that is often seen on foliage and flowers.

Native bush cockroaches generally do not infest homes. If one wanders inside it is an accidental visitor that can simply be put back outside. The species worth acting on are the introduced pests covered above, because they are the ones that breed indoors and contaminate food.

When Is Cockroach Season in Perth?

Cockroaches are active all year in Perth, but activity climbs through spring and peaks over the hot summer months. Warm nights bring outdoor species out to forage and fly, and long dry spells push them toward the moisture in kitchens, bathrooms, laundries and reticulated garden beds.

In winter, indoor species such as the German cockroach simply move closer to warmth. They shelter around fridge motors, hot water units, dishwashers and other appliances, so an indoor infestation does not disappear when the weather cools.

Warning: Perth’s coastal suburbs such as Rockingham, Mandurah, Secret Harbour and Port Kennedy often combine warm weather with heavily mulched gardens and regular reticulation. That mix of moisture and shelter right against the walls gives outdoor cockroaches an easy base close to your home.

How to Know When Infestations Occur

One of the most difficult aspects of dealing with cockroaches involves their nocturnal nature. Like rats and mice, it is often possible to have cockroaches infesting your building for months before you ever become aware that there is a problem.

Often times, the first indication is when a cockroach is seen in the early evening hours, or when a dead roach is discovered under a sink or near a drain. By that time, however, there is usually a larger infestation present.

If your property includes many areas with cracks, drains, or other confined spaces, or if you have a nearby garden, there is always the chance that cockroaches may make their way into your home or business. They are drawn to areas with food and water, which makes kitchens and bathrooms especially attractive.

However, damp basements – either cool or humid, depending on the type of roach, are also attractive locales. They can also hide in the cracks of cupboards, in grease traps, or among newspaper and magazine stacks.

If you even suspect that your home or business might have a cockroach problem, you should begin with an effort to inspect the premises. Obviously, the best way to do that is to search those areas in which the creatures are most likely to live: cracks, crevices, and damp, dark spots throughout the building.

If you have a good idea where roaches might be living, you can always leave out so-called roach stations or traps to see if you can catch some. These traps will bait cockroaches and trap them. While this is not a particularly effective way to deal with any infestation involving more than a handful of the creatures, it can be an effective way to determine whether you actually have a problem that needs attention.

Important: if you catch more than a handful of roaches, find small roaches indoors, or see a cockroach during the day, do not wait for it to sort itself out. Their fast breeding means an early treatment is smaller, quicker and far easier than tackling an entrenched infestation later.

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Related → Where Do You Find Cockroaches?

Preventing Infestation

Roaches have long been considered a sign of poor hygiene and a general lack of cleanliness. While this is not entirely the case – these creatures do seek out human habitations because they fulfill their primary needs, after all – there are certain things that you can do to help prevent infestations from occurring in the first place. And yes, these preventive measures tend to be centered around cleanliness.

• Make sure that the home or office building is cleaned thoroughly on a regular basis, with particular emphasis given to bathrooms, kitchens, and anywhere food is either stored or prepared. Don’t forget those common areas of neglect like around and behind the stove, behind and under the refrigerator, and so on.
• Don’t leave trash sitting around in your home. Be sure to empty trash bins daily, since many roaches can be drawn to that sort of decaying matter. It is also a good idea to keep outside rubbish bins some distance away from the home to discourage entry by roaches which might be out exploring and scavenging for food.
• Avoid leaving pet food out when domestic animals are not feeding. Roaches can be drawn to the food and will invariably contaminate it. That can make your animals sick, and lead to expensive veterinary bills that are otherwise easily avoidable.
• Seal up food in plastic containers. Roaches can chew through cardboard and bags, contaminate the contents, and cause illness for any humans who come into contact with the spoilage. Get into the habit of disposing of cardboard containers and relying on more effective sealing methods.
• Make routine home checks to identify any cracks or other gaps that could be used by roaches as hiding places. Seal them up as soon as they are found to ensure that new roach populations don’t find their way into your home or office.
• Keep compost heaps, gardens, and other roach attractions at a safe distance away from the home, to limit the enticements that might otherwise make them aware of your living space.

Extra Prevention Tips for Perth Homes

• Fix leaks and drips: cockroaches need water more than food. Repair dripping taps, leaking pipes under sinks and weeping dishwasher or washing machine hoses.
• Keep drains sealed: keep grates in place and run water through rarely used floor wastes so the water seal does not dry out, as drains are a common way in for American and Oriental cockroaches.
• Pull mulch back from the walls: leave a clear strip between garden beds and the house, and avoid pointing reticulation at the slab or brickwork.
• Seal doors and screens: fit weather strips under external doors and repair torn flyscreens, especially before summer.
• Check what you bring inside: German cockroaches and their egg cases often arrive in cardboard boxes, grocery deliveries and second-hand appliances. Unpack outside where possible and recycle cardboard promptly.
• Switch off unused outdoor lights: on warm nights, lights draw flying cockroaches toward doors and windows.

Warning: keep store-bought baits, powders and sprays well out of reach of children and pets, and follow the label exactly. Spraying surface insecticide over or near gel baits can taint the bait so roaches avoid it, and repellent sprays can scatter German cockroaches deeper into wall voids and appliances.

Related → Roach Repellent: 5 Ways to Keep Cockroaches Out | Get Rid of Cockroaches: 10 Useful Tips | Tips to Eradicate Cockroaches

Contacting the Professionals

As effective as smaller trapping systems can be at capturing specimens to identify an existing infestation, it is often unwise to rely upon do-it-yourself methods to attempt to completely eradicate the problems. The better solution is to contract a competent, licensed pest control company and allow the professionals to come in and take stock of the situation.

Qualified companies have the tools and expertise needed to identify the roaches, determine just how bad the problem is, and select the ideal solution to rid you of these pests once and for all. Remember, if you do it yourself and miss even a handful of the creatures, their rapid breeding will result in a renewed infestation in no time at all.

A professional pest control service will begin by conducting an evaluation of the problem. They will inspect the building to identify the extent of the infestation, determine the best range of options for resolving the matter, and make recommendations about what needs to be done to make your home cockroach-free.

Once you approve the process, they will implement the roach removal strategy to ensure that your home or office is free from this disgusting pest.

Competent pest control doesn’t end with removing the infestation, however. If roaches found their way into your building, then there is every reason to believe that other roaches will be able to do so as well.

To prevent that, roach control experts will work with you to identify the points of entry that roaches could be using to gain access to your home. They will then help you to ensure that cracks and other entry areas are properly sealed to ensure that no additional infestation occurs in the future. That can help to provide a more lasting solution than any do-it-yourself removal effort might produce.

That’s why it is so important to consider contacting professionals to deal with any pest infestation. And where roach problems are concerned, it is vital to contact the pros as early as possible.

Remember, if you see a roach during the day, that is a good sign that the population is extremely large. The good news is that real help is always just a phone call away!

Related → Cockroach Control Perth | Domestic Pest Control | Is Your Pest Management Company Licensed?

Cockroach FAQs

Do cockroaches fly in Australia?

Some do. The American, Australian and smoky brown cockroach can fly or glide short distances, mostly on hot, humid nights and often toward lights. German cockroaches rarely fly and Oriental cockroaches cannot fly at all.

What is the biggest cockroach in Perth homes?

The American cockroach is the largest common pest species, reaching up to 40mm. The Australian and smoky brown cockroach are close behind at up to 35mm.

See → Common Australian Cockroach Pest Types

What are the small cockroaches in my kitchen?

Small tan roaches of 10 to 15mm in a kitchen are usually German cockroaches, particularly if they have two dark stripes behind the head. Brown-banded cockroaches are similar in size but have pale bands across the body and prefer drier, higher spots.

See → Cockroaches in Your Home

How many types of cockroaches are there in Australia?

Australia has hundreds of cockroach species, but most are harmless natives living outdoors. Only a handful are household pests, mainly the German, American, Australian, Oriental, brown-banded and smoky brown cockroach.

When is cockroach season in Australia?

Cockroaches are active year round, but sightings rise through spring and peak in summer when warm nights bring outdoor species out to forage and fly. Indoor species keep breeding through winter near warm appliances.

Where do cockroaches hide in a house?

Cockroaches hide in cracks and crevices, behind and under fridges and stoves, under sinks, around drains and grease traps, inside cupboards, and among stacks of paper or cardboard.

See → Where Do You Find Cockroaches?

Does one cockroach mean an infestation?

Not always. A single large roach that flew in on a warm night may be a one-off visitor. Small roaches indoors, repeat sightings or any roach seen during the day are much stronger signs of a population living inside.

Are Rockypest cockroach treatments safe for children and pets?

Rockypest’s licensed technicians use products that are effective against cockroaches and safe for families and pets when applied correctly. Your technician will explain any simple precautions, such as keeping pets off treated surfaces until they are dry.

See → Cockroach Control Perth

How long does it take to get rid of cockroaches?

Most jobs show a quick drop in activity within days, with baits continuing to work over the following one to two weeks as roaches carry them back to their hiding spots. Heavier German cockroach infestations can take a few weeks to clear fully.

See → Cockroach Control Perth

What should I do after a cockroach treatment?

Follow your technician’s advice, avoid wiping away baits or treated areas, and keep up the cleaning and sealing habits above so new roaches have nothing to come back for.

See → How to Clean Your House After a Pest Spray

References

• Ellipsidion humerale (bush cockroach), Wikipedia
• American cockroach image: Sputniktilt, own work, CC BY-SA 3.0, Wikimedia Commons
• Cockroach image: Lmbuga, own work, CC BY-SA 3.0, Wikimedia Commons

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