Cockroaches

Cockroaches may vary in size from 10mm to 25mm (approximately one inch). They have long whip-like antennae and two pairs of wings. Only two species are widely distributed in this country, namely the Oriental cockroach and the German cockroach.

The Oriental cockroach is by far the commoner of the two species. The adults grow to about 24mm long. They are shiny and dark brown to black in colour.

They can climb rough vertical surfaces such as brickwork and often congregate around water sources.

The German cockroach adult is 10mm to 15mm long and is yellowish-brown in colour. It is capable of climbing smooth vertical surfaces such as painted walls. German cockroaches prefer warm moist conditions.

Habitat

Cockroaches can be found in premises where food is stored or handled. Oriental cockroaches are frequently associated with restaurants, hotels, hospitals, prisons and other institutions, old tenements and flats. Outdoors, they may be found around drains, dustbins and rubbish tips.
German cockroaches in Britain are pests of warm indoor environments, especially institution heating systems, bakeries, etc. They are nocturnal insects and will spend most of the day hiding in cracks and around drains and services ducting. Infestations may be introduced into premises in laundry and food deliveries. Their presence can normally be detected by faecal marks or their smell.

Importance

Cockroaches will feed on almost anything, including soiled dressings, faecal matter and food for human consumption. They are capable of carrying various food poisoning germs on their bodies and can be responsible for the spread of gastroenteritis, dysentery and typhoid. Contamination will occur when the insect comes into contact with food or work surfaces or through faecal contamination of foodstuffs. In addition, food may be tainted with the characteristic smell of the
cockroach.

Life Cycle

The female cockroach produces up the eight purse-like egg cases at monthly intervals. The egg cases are thick walled and are 6mm to 12mm in length and may contain up to thirty eggs. The nymphs of the German cockroach emerge from their eggs in two to four weeks and those of the Oriental cockroach in six to twelve weeks.

The nymphs are similar in appearance to the adult but smaller. As the nymph develops and grows it moults. This usually occurs between five and ten times during its development, which may take up to two years to complete until the insect reaches maturity. The life cycle is complete in a further four months for the Oriental cockroaches and nine months for the German cockroach.

Control

It is likely that an infestation has arisen because conditions of hygiene and cleanliness are below standard. It is essential that these are corrected before any control measures are carried out, since no amount of insecticide will control an infestation where housekeeping is bad. The following points should be considered:-

• Are the floors and walls clean and free from accumulated debris, particularly in corners and at the floor/wall junction?
• Are there any gaps or spaces on work surfaces, catering equipment, tiles, etc., that may provide harborage?
• Are the storerooms kept clean and clear of boxes etc.?
• Are floor drains clean with tightly fitted covers?

These and many other factors need to be examined before effective control methods can be carried out.

Proofing of Buildings

• Fill in any holes around pipes and cables where services (gas, electricity, water) enter the house, using cement/mortar or other suitable external filling compound.
• Fill in any holes around overflows, sink waste pipes, soil pipes and chimneys, etc., with cement/mortar or other suitable external filling compound.
• Seal outside windows and doorframes with mastic.
• Seal inside windows and door frames with general purpose household sealer.
• Cover air vents or airbricks with fine zinc gauze, fixed securely.

Commercial Premises

You will need professional help in treating a cockroach infestation, particularly if you run a commercial food premises. In this instance you should contact a specialist pest control firm. Names of such firms can be found in your local telephone directory.

Domestic Premises

Aberdeenshire Council's preferred contractor is Pro-Check Environmental Services Northern Ltd and they can be contacted on 08448 006484 The charge for insect treatment is £16.04