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Guide to Cockroach Infestations

Cockroaches are dreaded and feared by almost every person on the planet. They have been around forever and, thanks to their legendary ability to survive a nuclear holocaust, they will probably be around forever more. However, despite their bad rap, cockroaches are a species to be admired. They are well-organised and over millions of years of evolution have learnt to adapt challenging living conditions.

Cockroaches are also very intelligent. Since they discovered how easy and convenient it is to live with humans, making their homes in the cavities, nooks and crannies of our homes, they have consistently outsmarted, outmanoeuvred and outlived all of our efforts to get rid of them, including cockroach repellents, insecticides, bait traps and fumigation. So if you have a cockroach infestation, prepare yourself for a battle of wills and don’t hesitate to call in professional extermination services to help you deal with your roach problem.

About cockroaches

The earliest cockroach fossils date back to the Carboniferous period, which stretches back 295 – 345 million years. Not only are they one of the earliest forms of life, but cockroaches are also one of the hardiest, with some roach species able to survive on the scantest of resources, like the glue found on postage stamps. Others can go without air for three quarters of an hour, while still others can remain active without feeding for as long as 30 days. Experiments on cockroaches show that they can recover after being submerged in water for 30 minutes, and a Japanese cockroach (P. japonica) has survived temperatures between -5 °C and -8 °C for up to 12 hours!

Up until the 1870s, people were encouraged to grind up or boil cockroaches for medicinal purposes. Now we know that this is a tremendously bad idea because cockroaches are carriers of dysentery, diarrhoea, cholera, leprosy and typhoid fever.

Common cockroach species

There are roughly 4,600 cockroach species, about 30 of which can be identified within human habitats. Of these 30, four types of roaches are most common in towns, cities and countrysides all over the world: American cockroach (Periplaneta americana), German cockroach (Blattella germanica), Asian cockroach (Blattella asahinai) and Oriental cockroach (Blattella orientalis).

Some of the most common cockroach species include:

(a) American cockroach (also known as the waterbug): Among the largest of the common roaches, it thrives in tropical climates and prefers moist, dark places close to food sources. It usually enters buildings through sewerage pipes and floor drains. American cockroaches are reddish-brown in colour with a yellow margin behind the head.

(b) Australian cockroach (Periplaneta australasiae): Very similar to the American cockroach in size and colour, but with yellow stripes at the bottom of the wing pads and along the margin of the plate-like structure that covers part of the thorax. This species is not really an indoor cockroach but will seek warmth inside during cold spells. Australian cockroaches tend to infest greenhouses and zoos, or any locations where there is an abundance of decaying organic matter.

(c) Oriental cockroach: Is not able to fly and struggles to climb along smooth surfaces. It needs moist surroundings to survive and is often found in basements, crawl spaces and lower levels of buildings, as well as outdoors hiding in leaf litter, under logs and mulch. It is shiny and black in colour.

(d) Smokybrown cockroach (Periplaneta fuliginosa): Prefers to be outside in mulch, fallen leaves, ground cover and woodpiles, although it will come indoors to look for food. It is mahogany-brown in colour.

(e) German cockroach: A small type of roach that doesn’t even reach an inch long. It is a tan-light brown colour, with two dark stripes down its sides. Females are bigger than males. A German cockroach develops from egg to reproductive adult in 123 days. They thrive in residential buildings, feeding on meat, starches, sugars, fatty foods, soap, glue and toothpaste. German cockroaches are particularly resistant to extermination, so professional expertise is essential if your home becomes infested.

(f) Brown-banded cockroach (Supella longipalpa): Resembles the German cockroach in size and colouration, with two broad bands on the wings. It prefers warm indoor locations to being outdoors.

How to identify the common cockroach

In our mind’s eye, cockroaches are enormous, but the truth is that most roaches are about the size of a thumbnail. (There are some exceptions, such as the giant burrowing cockroach, which can grow to about 9cm (3.5 inches) in length.) Their bodies are broad and flat and their heads are relatively small. The mouth is found on the underside of the head, and they have large compound eyes as well as an additional pair of eyes known as the ocelli. On the top of the head are the antennae which are long and flexible.

Cockroaches have two pairs of wings; the first pair is tough and forms a protective shield over the membranous rear wings. Their legs are sturdy with strong bones that attach to the body. Each leg has five claws.

Cockroaches are nocturnal and scatter when the light is switched on, however the Asian cockroach is the exception and tends to run towards the light. has a user-friendly table of different types of cockroaches to help you identify your particular roach problem.

Cockroach communication

Most cockroaches make a hissing noise but some make a chirping sound. Some of the Australian species practise an acoustic and vibrational dance in a rhythmic and repetitive pattern as an aspect of the courtship ritual.

The primary method of communication is chemical. Cockroaches leave chemicals in their droppings for other roaches to find, usually communication the location of food sources or locations which provide perfect conditions for habitation. They emit a special pheromone for courtship purposes, and another pheromone for swarming.

How to get rid of cockroaches at home

People often think that cockroaches are a sign of dirt and unsanitary living conditions, but the truth is that most homes, even the neat-as-a-pin homes, will experience at least one roach infestation. Cockroaches are attracted to decaying matter, but they will feed on virtually anything, ranging from organic to inorganic matter, so glue, postage stamps, pet food and compost heaps will do. In addition to the creep-factor, cockroaches also leave a foul smell and passively carry microbes from drains and sewers, latrines and rubbish bins across your table surfaces, into your cabinets and over your crockery and cutlery and pots and pans. This means that cockroach infestations are not only inconvenient, but they are also serious health risks.

The most common signs of a cockroach infestation in your home include droppings, egg casings and an atrocious musky/oily odour.

If you want to prevent a cockroach infestation, you need to develop some good cleanly habits. Make sure you don’t leave food lying about on your tables or in your pets’ food bowls. Clean surfaces with a good germ removing cleaner and make sure you wash your pets’ dishes after every meal. Make sure the food in your cabinets or pantry is sealed, always keep your scullery and sink clean and no matter how tired you are after a long day or good party, don’t leave dirty dishes to pile up. Always give surfaces a good wipe down with a disinfectant after washing up or using the sink. Failure to do so will attract cockroaches.

If you don’t already have one make sure you get a rubbish bin that seals tightly and if your bin is in your kitchen empty it out daily. Vacuum behind your fridge and stove and in other spaces you don’t generally see or use, like far end of corner cabinets and underneath the sink. Seal off any holes or entry points in skirting boards and repair dripping taps or water leaks because these are also favourite cockroach entry points.

If you’re looking for an entirely natural way to get rid of cockroaches you can try the rather radical (although rarely advised) method of importing some wasps. Wasps are natural cockroach killers because they attack the egg cases and prey on the nymphs and adults by stinging the cockroach more than once and in very specific way. The first sting paralyses the cockroach for up to five minutes and the second sting goes straight into the cockroach’s brain. The wasp clips the antennae and drinks the haemolymph (blood-like fluid). It then carries the wounded cockroach by its clipped antennae to the nest where an egg will be laid on it, and from which wasp larvae will feed – while the cockroach is still alive. Another natural predator to the cockroach is your everyday house centipede.

If you would rather not infest your house with wasps to exterminate cockroaches (understandably), you might prefer the chemical route. Take note, however, that this process often needs to be repeated to ensure all cockroaches are killed and no eggs remain. Also remember that some cockroach species have developed immunity to certain poisons, so you might have to try a variety of bait stations, repellent gels with hydramethylnon or fipronil and pest control products (sprays) with deltamethrin or pyrethrin, as well as boric acid powder. Many of these commercially available pest control products are highly poisonous, so you need to be careful how you use them if you have children or pets in your house.

All in all, the best solution for getting rid of cockroaches is to call professional exterminators. In addition to the peace of mind that they will kill all of the cockroaches, you can also claim the costs of professional roach extermination on your home emergency insurance (if your policy covers pest infestations).