Cockroaches (Blattella germanica)

Where Usually Found

The household cockroach lives in dark, moist places adjacent to human food. Bush varieties, which are often gaily coloured and may not have wings, live outside in some areas of New Zealand.

What they do

Smell bad and frighten humans. The presence of cockroaches is generally and sometimes unfairly taken to be a sign of poor hygiene, food being left out, rubbish not being disposed of, accumulated grease and unwashed dishes. Household cockroaches rarely carry disease (isolated instances of salmonella and poliomyelitis have been reported) but spoil human food with their excreta and characteristic odour. Cockroaches eat food, paper and book-bindings.

How to control (by natural methods)

Keep food and dishes in cockroach-proof containers. Cockroackes and NymphsMesh sewer vents, drain holes and other orifices. Seal cracks between floorboards and gaps between bricks. Ensure that cupboard doors fit tightly. Cockroaches prefer dark places, so kitchen lights left on will act as a mild deterrent. Cockroaches like the warmth near hot water tanks and frequently used areas, and in summer they are more active. Frogs, reptiles, birds, mammals and spiders will catch and eat cockroaches.

Life history and other comments

Cockroaches have lived on earth about a hundred times longer than man, These insects have a flattened body that enables them to squeeze under bark and into small crevices. Their head is carried at right angles to the rest of their body. The long antennae act as sense organs with which to investigate their surroundings. Before cockroaches mate there is a simple form of courtship in which one or both of the individuals touch antennae, raise wings, or release a smell attractive to the opposite sex. Transfer of sperm from the male to the female occurs when the two individuals stand end to end. This process may take several hours. Cockroaches take about a year to reach adulthood, during which time they moult between six and twelve times. The maximum life span is about four years. Some varieties of cockroach have wings while others do not. When wings are present, the uppermost pair is always leathery and protects the under pair. The German cockroach produces more eggs per capsule than other pest cockroach species; and its young complete their growth in a shorter period of time. The German cockroach can grow from egg to adult in 36 days at 86 degrees F. Female German cockroaches carry their egg capsules until they are ready to hatch, and the capsule often becomes as large as the abdomen. The number of eggs in a capsule usually is between 30 and 40, with a maximum of 48.

Where to obtain professional advice


Melvyn or Kevin Gilbert. Phone. 03 3841636 (NEW ZEALAND)

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For inquires and free advice you can contact us via email or on 03 384 1636 from 8.30am - 5pm Monday to Friday.

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03 3841636