Cockroaches are another serious public health pest because they can spread a large number of gastro-intestinal and other diseases. They can be found in homes and domestic areas as well as commercial food premises, especially in blocks of flats, where they may live in kitchen ductwork and the drainage system.

The two most important species from the public health point of view are the Oriental cockroach and the German cockroach. The adult Oriental cockroach may be 24mm long and almost black in colour; only the males have wings. The German cockroach is smaller, 14mm long, and is yellow brown in colour; both the males and females are winged.

Cockroaches are nocturnal insects; spending the day in cracks and crevices where they are difficult to detect. When you start to see evidence of an infestation, it is usually well established and professional help is needed.

When cockroaches run over food they leave filth and may spread disease. They secrete an oily liquid that has an offensive and sickening odor that may ruin food. This odor may also be imparted to dishes that are apparently clean. Excrement in the form of pellets or an ink-like liquid also contributes to this nauseating odor. Some people are allergic to cockroaches and become ill.


The Oriental cockroach known as the "water bug," is more closely associated with damp areas than the other common roaches. These insects feed on garbage and decaying organic matter and are often considered the filthiest of the house-infesting roaches.

They are found in damp basements, cellars, crawl spaces, near drains, leaky water pipes and beneath refrigerators, sinks and washing machines, under floors, and inside walls. They forage mostly on first floors of buildings.

Outdoors, they are found beneath decomposing leaves or stones in mulching materials, in rubbish and at municipal sewer plants. During the autumn, there can be a mass movement into buildings, but because of their preference for cooler temperatures, they can be found outdoors and in unheated buildings during the winter.

Roaches can foul food and produce an unpleasant odor. Some homeowners are allergic to roaches, and the pests can contaminate food with certain bacterial diseases that result in food poisoning, dysentery or diarrhoea. Cockroaches can cause childhood asthma.


Pest control professionals often use sticky traps to find out the severity of the infestation. Insecticide sprays and/or baits are used to get rid of the cockroaches, but because they like out of the way hiding places, treatments may take many visits to fully eradicate the infestation