How to get rid of 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.






  • Cockroaches do not lay single eggs, but lay egg cases (ootheca) which may contain up to 40 young. The female cockroaches carry the ootheca around for a while, depositing it just before the young hatch. 
  • The young cockroaches look like a smaller version of the adults (although they lack wings). The young (or nymphs) moult through several stages before becoming an adult.  After each moult they have a very light or “albino” colour before their cuticle hardens.
  • Adult cockroaches look like brown “beetles”. It is not hugely important to be able to identify the species accurately, but they do fall into two general groups
german cockroach image


    • Small cockroaches: German cockroaches are pale brown, small cockroaches, adults up to 1.5 cm long.  These cockroaches only live inside and can be significant pests.
    • Large cockroaches: American cockroach is brown to dark brown cockroaches, with a lighter coloured band behind the head. Adults up to 5 cm long. Gisbourne cockroaches are dark brown with a light coloured band down either side of the front half of the body. Adults up to 4 cm. Both these cockroaches typically live outside (sewers, sub-floor and roof voids), coming inside for food or ‘by accident’.
  • Only adult cockroaches have wings and in many cases only the male cockroach has fully formed wings. The wings are not often visible as they are covered by the hard wing cases or elytra.


  • 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. This 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.


  • Cockroaches can be pests at any time of the year, especially the smaller cockroach species such as the German cockroach, which lives indoors. However, numbers tend to be higher in the warmer Summer months, especially for the larger cockroach species, which live outdoors.


  • German cockroaches only live indoors, particularly common in kitchens, bathrooms and laundries.  
  • A large number of German cockroaches can live together in a very small space. German cockroaches are often found congregating in electrical goods; toasters, kettles, microwaves and televisions.
  • The large cockroach species tend to live outdoors in moist areas; gardens, sewers and drains. This means they also like moist sub-floor areas. However, American cockroaches can be found in hot, dry roof voids.
  • Cockroaches will eat virtually anything, even each other!
  • Cockroaches are known to carry a large number of diseases, many of which cause stomach upsets.
  • Cockroach infestations can give rise to allergies and asthma and is probably the highest cause of asthma in many inner city apartment blocks.
  • As well as being nocturnal, cockroaches are very sensitive to vibrations and air movement, which is why the run away, often before the light is turned on.
  • Cockroaches are thigmotactic which means they like confined spaces. It also explains why the tend to run around the perimeter of rooms.
  • Although many adult cockroaches have wings, most species do not fly. Adult American cockroaches will fly, but only in warmer weather.
  • The names of the pest cockroaches German, American, Australian don’t really described where they come from, as they are found in many countries. For example in Germany, the “German” cockroach is sometimes called the “Russian” cockroach!
  • There are several species of native “bush” cockroaches in New Zealand, but these are not classed as pests.


  • 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. 



  • Cockroach baits are often the best option for eliminating cockroach infestations, especially of German cockroaches (the ‘small ones’) which live inside. However, you need to know how to use a cockroach bait to get the best results.
  • If you have a cockroach infestation, using a cockroach / flea total release aerosol (also called a fogger or “cockroach 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 insecticidal cockroach spray to get into some cracks / crevices / cupboards where the fogger may not have reached.
  • A crawling insect aerosol or ready-to-use pump spray are the best options for a preventative measure, particularly for 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 repeat more than once a year.
  • Crawling insect aerosols are the best product to kill any cockroach you see. These are designed to coat the insect with insecticide providing rapid knock down and kill. Flying insect aerosols will work but are not designed for crawling insects and so take a lot longer to work.


  • For direct spray on cockroaches, Pro-Spray Crawling gives the fast knockdown and kill you require. Pro-Spray is also great for spraying into cracks and crevices with its extendable nozzle and can also be sprayed upside down to get under cupboards.
  • If you have an pest outbreak, Pro-Fogger is the best solution to get the problem under control. Use one aerosol per room
  • For preventative cockroach treatments to stop cockroaches coming in from outside, Pro-Spray Outdoor Perimeter will provide long lasting protection.