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Australian Cockroach: Identification Guide

In the southeastern part of the United States, the Australian cockroach is also known as a Palmetto bug. This is because the Australian cockroach exceeds 1 inch in size. Although the Australian cockroaches are an outdoors species, they still impose a threat to infestation.

The Australian cockroach has a smooth, shiny light brown flat, oval body with a yellow circle around the head. The body measures 1.2 to 1.4 inches in length and 0.3 inches in width. Australian cockroach has two sets of flight-capable wings with a yellow stripe along the border of the front wings, three sets of legs, two small antennas, and two cerci.

I wouldn’t be wrong in saying that the Australian cockroach is essentially a copy of an American cockroach in appearance, with very minute differences that are difficult to spot. I have written this blog to make it easy for the reader to identify and differentiate Australian cockroaches from American cockroaches.

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1. Advion Cockroach Gel Bait (Review)
2. Gentrol IGR Point Source (Review)

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1. Combat Roach Traps (Easy than gel baits)
2. Hot Shot Foggers (To kill in masses – 95%)
3. Pet Safe Killers (Uses Essential Oils)
4. Ortho Defence Outdoor Roach Killer (Prevent Roaches)

Appearance, and Identification Points


Australian cockroach has a smooth, flat shiny light brown oval-shaped body with a yellow band circling the head. The body is covered with two sets of wings (visible and hidden) that do not extend beyond the body.

The wings cover a rough striated body instead, resembling a staircase. In addition, the visible set of wings has a yellow-colored border covering the anterior one-third of the wings.

The hidden set of wings helps the Australian cockroach liftoff; the visible set helps the cockroach glide and does not actively participate in flying.

Australian cockroaches have two antennas measuring 0.9 inches, three sets of legs, a paired cerci, and a stylus. The female roach does not have a stylus.


The adult Australian cockroach measures 1.2 to 1.4 inches (3.5 cm) in length and 0.3 inches (0.76 cm) in width. The Male is slightly larger than the female roach.

Identification Points

You are more likely to come across the American roach because of a larger population and home infesting capability than the Australian cockroach.

However, if you come across one, Australian cockroach can be identified on the following points,

  1. Australian cockroach is slightly smaller than American cockroach by a quater of an inch.

2. Australian cockroach has a more rounded body than American Cockroach.

3. Australian cockroach has a yellow band on the head and a strip on the border of wings.

4. The antennas of American cockroaches are bigger than the body, whereas Australians have a shorter antenna.

Distribution and Habitat

Australian roaches are cosmopolitan species with a presence around the globe. However, the name is a misnomer because they originated from Africa.

Australian cockroaches are present around the United States, especially the southern part where they infest home with greater probability. These roaches are cold intolerant and love to live in warm and humid climates of the tropics.

The Australian cockroach is a species of the outdoors but can infest homes when the outside temperature becomes intolerant. They are usually found in sewage drains, greenhouses, wood stock, and under the bark of fallen trees.

Inside the house, they usually nest inside the attic, and basements keep on infesting the house unless you pay close attention.

Australia Have Cockroaches

The geography of Australia is comprised chiefly of low lands, mainly deserts, and tropics. These places have a warm and humid atmosphere that favors cockroaches.

It is, therefore, common for Australians to get infested with several types of roaches, including

  1. Australian cockroach
  2. German cockroach
  3. Smokey Brown cockroach
  4. Oriental cokroach
  5. American Cockroach

Some of the biggest cockroaches are also found in Australia, including the Giant Burrowing Cockroach that measures 3 inches in size and 30 grams in weight.

Australian Cockroach: Diet and Life Cycle

The Australian cockroach is most active in the dark when it crawls around searching for food and water. Australian cockroach-like, their other cousins are omnivorous and feed on decaying matter, filth, garbage, and plant leaves. Inside the house, they love to feed on starchy and sweet items.

The Australian cockroach has an average life span of approximately two years, including the nymphal and egg stages.

Once the female mate, she lays ootheca containing 24 individual eggs after 45 days. She keeps on laying ootheca after 30 days for the rest of her life. The female Australian cockroach produces 20 to 35 ootheca in her life.

The eggs hatch after 40 days and give birth to nymphs. After successive 4 to 5 molts taking six months, the nymph transforms into an adult roach and keeps on living for the following year.

The female Australian cockroach has 3 to 4 months more life span than the male roach.

Are Australian Cockroaches Harmful?

No one likes a cockroach visiting your kitchen and playing on your utensils who lives inside sewage holes and feeds on filth.

Every cockroach, including the Australian cockroach, is harmful if it infests the home. Although Australian cockroach infests home with less severity, they still impose a threat to susceptible individuals, including patients with known allergies to cockroach droppings, exoskeleton, and saliva.

Australian cockroaches are also known to trigger asthma episodes in an atopic individual. They can also transmit typhoid and paratyphoid fever in endemic areas.

In some cases, when the outside temperature drops abruptly, the Australian cockroach will try to move inside the houses and establish its colony there. Soon the place will turn into a breeding ground with hundreds of roaches moving around.

In such cases, the Australian cockroach is a threat to the property, significantly affecting the selling price in the market.

Do you know that some people have an extreme fear of roaches called Katsaridaphobia? Read this fascinating article to know more about it.

Preventing and Getting Rid of Australian Cockroaches

The “idiom prevention is better” than cure stands true for an infestation with an Australian cockroach. This is because Australian cockroaches infest homes occasionally, but once they establish their nest, they can be difficult to exterminate without professional help.

However, I have a few methods to help you exterminate an established infestation with Australian cockroaches.

Method 1: Using Cockroach Baits

Using cockroach bait to kill Australian cockroach works wonders. This is because Australian cockroaches love to share the bait with their colony hence killing them.

The market is flooded with baits to kill roaches, including the Australian roach. However, I recommend using Advion Cockroach Gel Bait because of its superiority over other baits. All you need to do is,

  1. Place the advion gel bait at multiple location around the house including attic, basement corners, kitchen cabinets, drawers, bathroom and entry points.
  2. Wait for next few days to see the results.

Method 2: Using Cockroach Traps

The cockroach trap will kill Australian cockroaches by trapping them physically and poisoning them to death by a chemical insecticide. I recommend Hot Shot Liquid Cockroach Trapper and Killer because it is chemical-free and safe to use around pets and kids.

All you need to do is,

  1. Place the traps at recommended locations around the house especially near the roach nest.
  2. Remove the traps after a week.

Due to heavy infestation, sometimes the method needs to be used again.

Method 3: Using Insecticide Spray or Fogger

The quick and lethal action of using insecticide spray makes it superior to other methods. All you need to do is turn off the lights and close the doors.

Next, Spray the insecticide generously at the hiding places and wait for 25 minutes before you ventilate the room.

I recommend Bengal Roach Killer because it contains Nyler, a chemical that prevents reinfestation for up to 6 months.

You can also select several other roach killers among the Best insecticides & traps based on your needs. Boric acid is also very effective at killing Australian cockroaches but Is a bit messy and slow method.

Some people might experience infestation even after successfully eliminating them. To know Why do I see roaches after bombing? Read this article.

To prevent Australian Cockroaches from Invading your space, you must,

  1. Not disturb the colony of Australian cockroach near your house, you might trigger them into entering your home.
  2. Cover greenhouse properly to avoid Australian cockroaches from getting into it and then to your house.
  3. Cover bathroom drains and sewage holes, the smell from these attract Australian cockroach.
  4. Cover garbage bins and properly dispose off decaying matter, especially decomposing leaves.
  5. Keep your house clean and well ventilated.
  6. Fix leaking pipes and faucets.
  7. The firewood should be inspected before bringing them to the house.
  8. Install window mesh screens in because Australian cockroaches are extremly good flyers.
  9. Use natural cockroach repellents inside the house, especially the kitchen.
  10. You can also use IGR spray to keep baby Australian roaches from maturing into adult bugs.

Do you know cockroach also produces noise? Click the link if you want to hear roaches’ noise.