How To Identify Pest Cockroaches
Cockroaches come in many different varieties, shape, colour and size. While there are hundreds of species found in Australia, only a few
are regarded as household pests. All of the pest cockroach species share a similar nature, they look alike, live indoors,
and thrive in a warm environment. The information below mentioned outlines their characteristics and will
help you decide on the most appropriate cockroach control measures you can take.
Pest Cockroach Species
There are five different pest species of cockroaches found in Sydney.
German Cockroaches
The German cockroach is a small tan coloured insect measuring around 5mm in length. Adults can be distinguished by two dark vertical stripes running down their back. They have fully developed wings but cannot fly.
German cockroaches are the most common roach species. They like areas that are warm and humid, such as kitchens and laundries. They are scavengers who will feed on anything but prefer fatty greasy foods. As they are small, they can avoid detection until infestations are severe. High density areas and apartments are attractive to them. They are one of the most difficult species to eradicate from homes.
Unlike most cockroach species, German cockroaches carry their egg sac until hatching. The small brown case is around 6-9mm in length. The tip may be seen protruding from the female’s abdomen. Newly hatched known as nymphs are white but darken with maturity. They are wingless and dark brown to black with distinct dark bands.
Australian cockroaches
The Australian cockroach looks similar to the American cockroach but is smaller and darker. Their average body size is 23-35mm in length. Adults have bright yellow markings on the thorax and wing base, making them easy to identify. They are good flyers.
Australian cockroaches are found outdoors around vegetation and greenhouses, where they may damage seedlings. Their favoured diet is plants, but they will feed on most household items. They are often brought indoors with items such as firewood and boxes. They prefer warmer temperatures than the American cockroach. Common habitats include the roof, wall and subfloor voids of homes.
The ootheca is reddish brown to dark brown. The case is dropped before hatching or attached to an object. The nymphs are dark brown and wingless but resemble adults when mature. Older nymphs have a yellow spot on their abdomen. This distinguishes them from the nymphs of other cockroach species.
American cockroaches
The American cockroach is one of the largest roaches in Australia, growing up to 50mm in length. These roaches are a reddish-brown colour, with a distinctive yellow band behind their head. They have fully developed wings that cover their abdomen. They can run fast and are capable of clumsy flight.
American cockroaches live in outdoor environments such as drains, sewers and garbage dumps. They prefer high temperatures and cannot tolerate cold. They are attracted to decaying matter and sweet foods. They enter homes through gaps, seeking out basements, bathrooms and moist areas. Water is essential to their survival. They can live in drier areas if a water source is available.
The eggs are contained within a protective case (the ootheca). The dark brown case is around 8mm long and dropped by females before hatching. It may also be glued to a surface by secretions. Nymphs are pale and wingless, later turning a reddish brown.
Smokey Brown cockroaches
The Smoky brown cockroach resembles the American cockroach but is a dark brown mahogany colour. It has noticeably long wings and can grow up to 30mm in length. They can fly well.
Smoky brown cockroaches prefer warm moist environments and are often found in greenhouses. They are a common pest in the nursery industry and also an indoor pest. They are attracted to light and often fly through windows. Areas of the home likely to be infested include kitchens, crawl spaces and storage areas. While plant material is the preferred diet, they will feed on almost any material inside the home. This includes sweet and starchy foods, and garbage.
Egg cases are dark brown to black (10-14mm long) and may be found glued to walls, floors and furnishings. Nymphs are black. They can be identified by two white bands across the body. They also have long antenna with a white tip.
Oriental cockroaches
Oriental cockroaches are large insects, with adult males measuring around 25mm and females around 32mm in length. They are a glossy black or dark brown with underdeveloped wings. They prefer to run rather than fly, and are slower moving than most roaches.
These insects live outdoors in cool environments. Common habitats are underneath wood and decking and damp areas. They are also found around sewers and drains. This species is very dependent on water. Oriental cockroaches may occasionally infest homes during summer, preferring the lower floors and crawl spaces. They consume starchy foods and decaying organic matter. This roach has an unpleasant musty odour.
The female carries the ootheca for a brief time. The egg cases are black to brown in colour (around 8-10mm long). They are dropped in hidden areas shortly before hatching. Nymphs are reddish brown to black and mature slowly. They behave the same as adults, hiding beneath vegetation and garden mulch.
brown banded cockroach
The brown banded cockroach is the smallest of the invasive roaches. The adults have distinctive tan stripes on their wings. Adult males can fly, while females have underdeveloped wings. These roaches like warm areas with low humidity. They often find their way indoors hidden in objects such as furniture and appliances.
The brown banded cockroach is the smallest of the invasive roaches, measuring around 10-15mm in length. The adults have distinctive tan stripes on their wings. Adult males can fly, while females have underdeveloped wings.
These roaches like warm areas with low humidity. They often find their way indoors hidden in objects such as furniture and appliances. Unlike German roaches who congregate in the kitchen and laundry, brown banded roaches are not as dependant on water. They can live in any area of the home. A common location is on ceilings and walls. They prefer to eat starchy materials such as glue and paper.
