Scavengers by nature, cockroaches pose a threat to health and hygiene in shops, office, commercial, industrial and residential buildings. Because of their predilection for drains, sewers and rubbish, they are a major source of disease and failure to control them in public premises could incur fines under both the Health Act and the Occupational Health and Safety Act.
The two species common in South Africa are the American cockroach (Periplaneta americana) and the German cockroach (Blattella germanica).
Cockroaches
The American cockroach species is the largest of the house infesting cockroaches being 30-45 mm long with fully developed reddish/brown wings and pale yellow markings on the thorax. Females produce egg capsules each containing up to 16 nymphs and under optimum conditions the nymphs reach sexual maturity in about 5-7 months. The adult life span may extend to 1 year. These cockroaches mainly breed in the sewerage drains.
The German cockroach, also thought to have originated in tropical Africa, is the more common and is now distributed by commerce to virtually all parts of the world. They prefer warm moist conditions and have consequently become a common pest of buildings, notably kitchens, larders, canteens, restaurants, store rooms and galleys. Gregarious and nocturnal by nature, they spend the day hiding in cracks and crevices around such areas as sinks, drains, cookers, cupboards and refrigerator motor compartments. They especially favour buildings with service ducts and complex plumbing installations. Infestations may be introduced as egg cases or adults in incoming laundry, or raw materials, in crates and packaging, or arise as the insects enter buildings via such routes as drains and refuse shoots. They are prolific breeders and the adult measures 12-15 mm long, buff coloured with two distinct dark parallel bands running along the thorax. The egg case is carried by the female until the eggs, numbering 30-40 hatch. Development to adult takes 6-7 weeks.
Significantly, cockroaches are potential vectors of diseases such as dysentery, gastroenteritis, typhoid, tuberculosis, leprosy and poliomyelitis. The diet is omnivorous and includes fermenting substances, soiled dressings, hair, leather, wallpaper, faeces and food for human consumption. The latter may be contaminated either by the mechanical transfer of causative agents of disease from the insects body or by transmission in the faeces. In addition, food may be tainted with its characteristic obnoxious smell.
In short, cockroaches are a major threat to health, property and profits.
