Cockroaches are sometimes confused with black garden beetles. They are distinguished by their very long “whip-like” antennae, flat oval bodies and rapid, jerky gait.
The adult German cockroach is 10 to 15mm long. The Common or Oriental cockroach is 20 to 24mm long. They thrive around the heating ducts and boiler rooms in large centrally heated buildings. They cluster around pipes, stoves and sinks, especially in humid areas.
The female German cockroach carries her egg case, a small brown purse-like capsule, until the 30 or more nymphs are ready to hatch. This means that an infestation of German cockroaches can be localised. The female Oriental cockroach deposits her 13mm long egg capsule on packaging, sacking or in suitable dark crevices before the 16 or 18 nymphs hatch.
Cockroaches grow in stages; they shed their skins as they reach maturity. This is 6 to 12 months for the Oriental cockroach, but a few weeks in the case of the German cockroach.
Both species eat any sort of food and have cannibalistic tendencies. They are most active after dark and as they forage, they will contaminate food, utensils and preparation surfaces.
They taint food with an obnoxious smell and may be carriers of various diseases.
They can cause serious food poisoning.
How to deal with them
The problem when dealing with cockroaches is the difficulty of getting the insecticide to the insect. The insecticide should be potent enough to kill the, as yet, unhatched nymphs as they emerge from the egg cases.
This can be purchased from a DIY store in the form of an aerosol spray or a powder. Apply the insecticide into all the possible harbourages.
Always read and follow carefully the instructions on the product. We cannot be held responsible for any misuse.