Common Pests

Cockroaches

Cockroaches are primitive insects whose origin extends back at least 300 million years and are thought to have originated in the tropical and sub-tropical areas of Africa. The advent of travel and international trade has brought about the spread of cockroaches to most countries in the world.

The omnivorous appetite of cockroaches makes any unprotected foodstuffs susceptible to cockroach infestation and contamination. Their indiscriminate feeding sources in such areas as sewers, drains and garbage areas bring them in contact with disease organisms including salmonella and other organisms associated with dysentery, typhoid, hepatitis and tuberculosis.

Cockroaches are nocturnal creatures and are seldom seen in any quantity during daylight hours, however, in areas where there are heavy infestations, sightings of cockroaches may become more common. It is generally accepted that for every cockroach seen there are at least a further ten that are hidden away in out of sight harbourages. Common harbourage areas include cracks and crevices, dishwashers, electrical motors and switches, ovens and almost any warm, moist areas where food is available.

Tell tale signs indicating cockroach activity include the presence of egg cases, regurgitation marks, faecal pellets, odour and cast-off nymphal skins.

Infestation occurs when cockroaches are carried into premises on raw materials or packaging or gain entry to the premises through drain covers, ventilation openings and under doors.

Following mating, the female cockroaches enclose their eggs in purse-shaped egg cases which they deposit or glue onto a surface prior to the eggs hatching. The young cockroaches, or nymphs as they are referred to, emerge from the egg case and over a period of up to a year, go through 5-12 moults as they increase in size. They achieve adulthood after the final moult and are capable of breeding 2-3 weeks later.

They are prolific breeders with the most common of the pest species, the German cockroach, being capable of producing 20,000 offspring within a twelve month period. Female cockroaches also have the ability to produce young without mating. This is referred to as parthenogensis.

COCKROACH CONTROL

Successful cockroach control begins with a thorough inspection to identify the species and to define the extent and source of infestation. A programme is prepared combining the elimination of food sources, gaps and crevices where they live, use of trapping and selective use of compounds.

The compounds used for cockroach control are of low mammalian toxicity and do not persist in the environment. The various compounds used are usually so pest specific that they have little effect on non-target species.