German Cockroach, Blattella germanica
Cockroaches are nocturnal by nature and spend the day hiding in cracks around areas like sinks, drains, cookers and the backs of service ducts. They may be seen if you come home in the dark and put the lights on.
They also emit an unpleasant almond like smell – only noticeable if the infestation is large. The German cockroach is a small species of cockroach, measuring about 1.3 cm to 1.6 cm (1/2″ to 5/8″) long.
It is tan to light brown, and has two dark parallel streaks running from the head to the base of the wings. Although it has wings, it is unable to sustain flight.Nymphs have a pale area centrally on the dorsal thorax.
The German cockroach is one of the most common and prominent household cockroaches in the world, and can be found throughout many human settlements in the world. These insects are particularly fond of inhabiting restaurants, food processing facilities, hotel rooms, and nursing homes. In colder climates, it is found only near human habitats.
The German cockroach is originally from Asia and it is also very closely related to the Asia cockroach to the extent that to the casual observer they appear nearly identical and may be mistaken for the other.
The German cockroach has three life stages typical of insects with incomplete metamorphosis: the egg, nymph, and adult. The entire life cycle is completed in about 100 days. However, factors such as temperature, nutritional status, and strain differences may influence the time required to complete a life cycle.
German cockroaches breed continuously with many overlapping generations present at any one time.
Under ideal conditions, population growth has been shown to be exponential. Actively growing field populations are comprised of 80 percent nymphs and 20 percent adults.
The German cockroach is omnivorous, eating table scraps, pet food, and even book bindings.
- Adult size: 13 -16 mm
- Number of moults: 5 – 7
- Development time (Egg to adult): 1 – 3 months
- Length of adult stage: 3 – 6 months
- Number of ootheca produced in female lifetime: Average 5
- Number of eggs produced per ootheca: Average 30 – 40
How they affect you
Cockroaches can carry dysentery, gastro-enteritis typhoid and food poisoning organisms.
Germs can be spread from the body of the cockroach or from the droppings they leave behind. Cockroaches will feed on almost anything including faecal matter. Contamination occurs when the cockroaches come into contact with foodstuffs.
Eradication of cockroaches can be complicated and should be carried out by professional pest control operative. They are difficult to treat, their hiding places are often difficult to reach with insecticides and because of the efficiency of the breeding process and the large number of eggs produced, cockroaches are difficult to eradicate and a Comprehensive eradication program is essential. The first step is to monitor the level of the infestation. Inspections should be carried out at night, when the cockroaches are most active, using a torch with a red filter which cockroaches do not respond to. A high standard of hygiene is important in the control of cockroaches and involves refusing access to food and water. This will increase cockroach activity and directed movement increasing the chance of the insects coming across insecticides. Inspections should be carried out at night when the cockroaches are active.
Effective treatment would depend upon the selection and thorough application of an appropriate insecticide. Many insects and egg cases are well hidden and therefore the insecticide must be placed at and around these harbourage s and maintained over the developmental period of the particular species. To control an infestation the insecticide should, if at all possible persist until all egg cases have hatched sustained immigration may demand routine treatments. Regular treatments are necessary at weekly intervals until the infestation is brought under control.
Then maintenance treatments at less frequent intervals, should keep the insect population at an acceptable level. In the beginning there will be a considerable kill of adults and nymphs resulting in only the appearance of young nymphs from time to time. When using sticky traps appropriate placement sites would be beneath equipment, in roof spaces, behind counters, inside ducting and electrical trunking. When cockroaches become trapped they are known to produce aggregation pheromones which make the trap more attractive.
Cockroaches are potential carriers of diseases such as dysentery, gastroenteritis, typhoid and poliomyelitis. Cockroaches are also a source of allergens which can lead to allergic illnesses such as dermatitis, rhinitis, bronchitis and asthma. Their diet is omnivorous and includes fermenting substances, soiled septic dressings, leather, parchment, faeces, hair and food for human consumption. The food may be contaminated by the mechanical transfer of causative agents of disease from the insect’s body or by transmission in the faeces. Cockroaches foul their environment with droppings, castings and regurgitated food. They can taint materials with their distinctive unpleasant smell.