How to Control Cockroaches

Cockroaches are probably the most unwanted pest in the home. Their connection with filth and quick scurrying movements certainly create a lot of anxiety. For some, the appearance of just one cockroach can make them feel as if they are a bad housekeeper (although often it is not their fault).

Fortunately with a combination of good prevention tips and suitable pest control products, most cockroach problems are easy to control.If you want to know a bit more about cockroaches – types of cockroaches, the cockroach life cycle and other interesting facts, read one…

Cockroach Identification

Types of Cockroaches

There are over 4500 species of cockroach globally, but only around 30 of them are considered as pests. Here in Australia there are 6 common pest cockroaches.

Pest cockroach species

Generally speaking the pest cockroaches can be broken down into “large cockroaches” and “small cockroaches”.

Large cockroaches

The large cockroach species typically live outside the home in drains and gardens, but will also set up home in the roof void and sub-floor. Generally these cockroaches come inside looking for food or moisture, or simply “by accident”. These cockroaches are often referred to as peridomestic cockroaches as they spend time inside and outside buildings.

The common large cockroach species in New Zealand are the Australian cockroach, American cockroach and Gisborne cockroach (shining cockroach).

Australian cockroach

Size: Up to 35 mm

Reddish / brown cockroach, with pale band around the pronotum (shield covering the head) and along the upper margin of the forewings.

Will fly in warmer weather.

Found outside and inside the home – leaf litter, drains, sub-floor and roof voids.

American cockroach

Size: Up to 40 mm

Reddish / brown cockroach, with pale band around the pronotum (shield covering the head).

Will fly in warmer weather.

Found outside and inside the home – leaf litter, drains, sub-floor and roof voids.

Shining cockroach or Gisbourne cockroach

Image credit: Nurg. CC BY 4.0

Gisbourne cockroach (Shining cockroach)

Size: 20-45 mm

Dark, shining cockroach with pale edges to its body

No wings

Prefers gardens, feeding on wood material

Small cockroaches

The small pest cockroach species typically live exclusively inside the home. As such, these cockroaches are often referred to as domestic cockroaches. The two most common small cockroach species are the German cockroach and brown banded cockroach.

Both these species are able to set up their home in the smallest of places – including door hinges, dishwashers, toasters, microwaves – and with their prolific breeding, they can be a lot more difficult to spot and control.

German cockroach

Size: Up to 15 mm

The adult German cockroach is a mid brown cockroach, easily identified by the two dark vertical stripes on its pronotum (the shield behind its head).

Although they have wings, they do not fly.

Only found inside buildings – primarily kitchens aas well as bathrooms and laundries.

More information on German cockroaches.

Brown banded cockroach

Size: Up to 15 mm

Mid brown cockroach with two light coloured bands across the body

Males can fly, female have shortened wings and cannot fly

Found inside buildings – dryer locations that German cockroach – living areas and electrical equipment

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Key Cockroach Facts

Cockroach egg cases – ootheca

Cockroaches will eat virtually anything, even each other!
German cockroaches do not stray far from their hiding places – adults only travel 1-2 m from their harborage. The young cockroaches do not leave their hiding place at all, eating the vomit and faeces of other cockroaches to survive!
The American cockroach has been measure running at a speed of 5.4 km/h, which would be comparable to a human running at 330 km/h.
Cockroaches are thigmotactic which means they like confined spaces. It also explains why the tend to run around the perimeter of rooms (so they can feel the wall).
Although many adult cockroaches have wings, most species do not fly. Adult American and Australian cockroaches will fly, but only in warmer weather.
The names of the pest cockroaches German, American, Australian don’t really describe where they come from, as they are found in many countries. For example in Germany, the “German” cockroach is sometimes called the “Russian” cockroach!

COCKROACH DISEASES:

Given the places that cockroaches hide, including the sewer, drains and in the garbage, it is perhaps not surprising they are viewed as “dirty” animals. Indeed, cockroaches carry a range of diseases, including Salmonella, dysentery and polio, as well as a number of other bacteria that give rise to stomach upsets.

However, it is the shed cockroach skins and droppings that cause the biggest problem, as they contain allergens. In cockroach infestations these can give rise to allergic reactions and asthma – cockroach infestations are probably the highest cause of asthma in many inner city apartment blocks.

Life-cycle of a Cockroach

German cockroach nymphs — German cockroach nymph (different instars / ages)

Cockroaches are a primitive insect. Cockroaches hatch from eggs into nymphs (young cockroaches) and go through several stages before becoming an adult. As the cockroach nymphs are similar to the adults (just smaller and lacking in wings), this process is called incomplete metamorphosis. This is unlike the transformation of a caterpillar into a butterfly which is a complete metamorphosis (complete change in body form).

The length of the life-cycle depends on the species (generally larger species have a longer life-cycle) and the temperature (higher temperatures mean a faster life-cycle). The life-cycle but can vary from between 3 months and 2 years.

Cockroach eggs

Cockroaches don’t lay eggs but have egg cases. These egg cases can contain between 16 and 40 eggs, depending on the species – smaller species have more eggs. The eggs develop into nymphs inside the egg cases and emerge as live young. Some cockroach species, such as the German cockroach carry the egg case until just before hatching, others such as the American cockroach place their egg cases near a food source for later hatching.

Egg cases in cardboard boxes are a common way cockroach population get started in homes!

Baby cockroaches

“Baby” cockroaches are called nymphs. These are the young cockroaches that go through several nymphal stages or instars before turning into an adult. The first instars can be very small – newly hatched German cockroaches are only 3 mm long.

Depending on the species they may have between 6 and 14 instar stages before developing into the adult cockroach. During each stage they get bigger, with the wings gradually forming through each stage so they are fully formed in the adult.

White cockroaches

Every now and then a homeowner will spot a white cockroach. Alas this isn’t a new species or a freak of nature, but a normal part of the cockroach life-cycle. As cockroaches have a hard cuticle, they cannot grow continously. When they are ready to grow, they shed their skin. When they emerge their cuticle is white and soft. This gives them the chance to expand and grow. Over next 1-2 hours the cuticle darkens and hardens.

Flying cockroaches

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Signs of a Cockroach Infestation

As cockroaches are nocturnal, often you many only see one or two cockroaches. But when you see one or two, you know there will be a lot more hiding in the cracks and crevices. If you are seeing cockroaches during the day, the chances are you have a significant infestation.
With a significant infestation you will often find “spotting” in the corners of cupboards or hiding places. These spots are the faeces and vomit of cockroaches.
Other signs of an infestation include old “skins” left behind when cockroaches moult and empty egg cases.
If there is a significant infestation, there will often be a characteristic cockroach smell.

Cockroach droppings

Cockroach droppings are obviously gross, but if you know what you’re looking for, they can be a sign you have a cockroach problem.

Large cockroaches produce more obvious droppings, more like a small pellet, whereas German cockroaches produce droppings which are more like spot, often with some liquid. When there are a large number of spots in one location, it indicates you have a major infestation on your hands!

Cockroach droppings are a major source of allergens that can cause asthma.

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Cockroach Prevention Tips

Cleaning dirty cooker — Keeping appliances clean removes attractive cockroach foods sources

Good Hygiene Is Critical:

Clean away spilled food and dirty dishes straight away
Ensure rubbish is put in secure containers
Put on the dishwasher regularly (cockroaches love dishwashers – food and moisture a plenty!)
Don’t leave pet food out overnight
Fix any leaks / areas of moisture
Fill any cracks and crevices
Don’t store cardboard boxes in the sub-floor
Keep an eye out for egg cases coming in on cardboard boxes as this is a common source of infestation.

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Cockroach Control Tips

Releasing a cockroach bomb — Cockroach bombs are great for infestations

Cockroach gel application — Cockroach gels are great for German cockroaches (infestations and prevention)

pestxpert outdoor perimeter spray — A cockroach spray around the perimeter of the building is great for prevention

Cockroach Products

A range of products are available to control cockroaches. Whereas a cockroach spray inside and outside the home may be good for large cockroaches, for small cockroaches (German cockroaches) and cockroach infestations, it is often necessary to use a number of different products in combination.

Cockroach Bait

Cockroach baits are the best option for controlling infestations in kitchens and sensitive areas. They can also be used as a preventative treatment in properties which have ongoing cockroach problems (as is often the case in blocks of units where cockroaches can move between units).

Cockroach baits come into two forms; solid bait in plastic bait stations as found in most supermarkets and cockroach gel baits which are used by pest professionals. Whichever bait product you use, it’s important to know how to use a cockroach bait, so that you get the best results.

COCKROACH GEL

Cockroach gels are preferred by pest professionals as they are generally more attractive than solid baits but most importantly they are more flexible in application. Most homeowners will not have used cockroach gel baits before so it’s important to know how cockroach gels work.

Bait can be placed on vertical and horizontal surfaces and even in tight areas such as cupboard hinges, allowing you to target cockroach hiding places.
As German cockroaches don’t travel far from their hiding places (and you don’t always know where they are hiding!), lots of small bait placements rather than a few bait stations will deliver better results.

Cockroach Bomb

“Cockroach bombs” also know as cockroach foggers or total release aerosols, are a great way to easily treat a whole room. The ultra fine mist they can get into the cracks and crevices where the cockroaches are hiding. Although they are great for cockroach infestations, they can also be used as a preventative measure. To ensure the cockroach bomb is used safely and effectively it is important to know how to use a cockroach bomb.

PestXpert Pro Fogger is a unique cockroach bomb formulation as it contains a combination of 3 active ingredients to create a professional formulation:

An insecticide to kill cockroaches and other pests on contact
A synergist to magnify the effect of the insecticide so it works even at very low levels
An insect growth regulator that breaks the breeding cycle and prevent pest outbreaks for many months

Cockroach Spray

A cockroach spray is a must in any Australia kitchen cupboard! But to get the best performance it’s important to know how to use a cockroach spray and how surface sprays work.

PestXpert Pro Spray Crawling aerosol provides a professional formulation and aerosol delivery system to allow easy, accurate application for quick kill and long lasting protection.

Dual insecticide formulation for fast kill and long lasting protection
Extendable nozzle to access cracks and crevices
360 degree valve, so you can spray upside down to get under cupboards and appliances

Cockroach Traps

Which Products to Apply When?

Infestations

Cockroach baits are often the best option for eliminating cockroach infestations, especially of German cockroaches (the ‘small ones’) which live inside. Indeed German cockroaches are one of the most difficult pests to control (even for professionals), so you need to know how to get rid of small cockroaches.

If you have a cockroach infestation, using a cockroach / flea total release aerosol (also called a fogger or “bomb”) is also a good option for getting numbers under control quickly and to also provide residual control. You will need one aerosol for each room. The treatment may need to be supplemented by an insecticide spray to get into some cracks / crevices / cupboards where the fogger may not have reached.

Prevention

A crawling insect aerosol or ready-to-use pump spray are the best options for a preventative measure, particularly if you are trying to get rid of large cockroaches which live outside and find their way inside. Spraying insecticide around the perimeter of rooms, in cupboards and other insect hiding places, as well as spraying the outside perimeter of the home, garbage bins and sub-floor areas, will keep the cockroaches out of the house, preventing a potential pest outbreak. These treatments may need to be repeated more than once a year.

Direct spray

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PestXpert Products For Cockroaches

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FAQs about Cockroach Control

How to get rid of German cockroaches?

How to get rid of cockroaches in the kitchen?

Cockroaches tend to congregate in the kitchen as there is plenty of food and water. They will typically hide behind and under cupboards and appliances. If you have a German cockroach infestation, they can get into all manner of small cracks and crevices including inside appliances, inside dishwasher control panels and around door hinges. It’s not appropriate to spray in a lot of these places as they are food preparation surfaces. The use of cockroach gel baits is the best option.

What attracts cockroaches?

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How to Control Cockroaches

Cockroach Identification

Types of Cockroaches

Pest cockroach species

Large cockroaches

Australian cockroach

American cockroach

Gisbourne cockroach (Shining cockroach)

Small cockroaches

German cockroach

Brown banded cockroach

Key Cockroach Facts

COCKROACH DISEASES:

Life-cycle of a Cockroach

Cockroach eggs

Baby cockroaches

White cockroaches

Flying cockroaches

Signs of a Cockroach Infestation

Cockroach droppings

Cockroach Prevention Tips

Good Hygiene Is Critical:

Cockroach Control Tips

Cockroach Products

COCKROACH GEL

Which Products to Apply When?

PestXpert Products For Cockroaches

PestXpert Pro-Spray Crawling

PestXpert Pro-Fogger Multi-Insect Bomb

PestXpert Pro-Spray Outdoor Perimeter

FAQs about Cockroach Control