Latin: Blattella germanica
Cockroaches are not a common phenomenon in Denmark – and yet. In Denmark we find the German cockroach, which is the most common house cockroach here. This pest is related to grasshoppers and crickets and do have common characteristics.
Appearance
Typically, the German Cockroach, also known by the name Blattella germanica, can be recognized by the oval and flattened body as well their characteristic legs.
This species of cockroaches can grow up to 1.6 cm long and the large cover wings that covers the entire hind body. It is distinctive by the yellow-brown body with two dark stripes on the back shield. The cover wings cover the flying wings, but it seldomly happens that the German Cockroach uses their wings.
Biology and behavior
A German cockroach typically belongs in a warmer climate than in Denmark, and therefore they are also dependent on being able to find warm places to live. Cockroaches eat everything and they are especially active during the night. In the light hours, they hide away in cracks and crevices, you will often find them close to appliances that emit heat. The cockroach prefers a temperature of between 25-30 degrees. However, to survive it is essential that they have access to water.
The mating of the German cockroach is controlled by scent signals, where other cockroaches are attracted to fragrances found in the excrement. This is also why cockroaches often attract each other. After mating, the female will lay eggs in special egg capsules. These are brown in appearance and consist of 30-40 small rooms. Each room contains one egg – the German cockroach does not throw the capsule after laying. Instead, the female carries it around until the cubs can move and take care for themselves, in this way, she also protects the eggs from drying out. The hatching time is approx. 28 days. The female lives for 120-170 days and produces 5-6 egg capsules with as many as 30-40 eggs in each.
The development of the young cockroaches happens through 6-7 nymph stages, where the nymphs are small and wingless. The favorable conditions for development are approx. 30 degrees, where the development takes two months.
At 25 degrees, the development from egg to adult takes approx. 100 days.
Damage
As a pest, the German cockroach is not known to cause major damage. However, they can spread diseases in your home, even though it rarely happens. The cockroach can cause skin irritation, allergies and affect asthmatic.
In the home, the cockroach can destroy different food stuff, as it will search for food. They will typically leave excrement in the food, which results in an unpleasant odor. This is a major challenge for food producers as well as restaurants, where the damage is less in private houses.
Prevention and pest control
Fighting the cockroach is not straightforward, you must be careful about killing it. A dead cockroach will send out fragrances that attract other cockroaches – and thus it can worsen the problem. An important part in the control of the cockroaches is that you create poor living condition for them. Make sure to remove water and plant food. At the same time, the pest needs heat and cracks in the home, therefore it is important to remove as many of these conditions as possible. Especially behind refrigerators, ovens and the like there are good living conditions for the cockroach. These should therefor be placed with some distance to the wall so that you can clear thoroughly behind them.
If your home has been attacked by cockroaches, you can use approved pesticides for chemical control against the German cockroach. Agents like this are used as poison passages which the cockroaches must pass. You should place a bait and water near those passages, and they should be placed near areas where the pests typically reside. Like at pipe penetrations, panels, and similar places.
It is important to be aware that cockroaches are good at avoiding the poison, as they find places where the poison is only applied in a thin layer. It is therefore important to be very through when treating against cockroaches. Fortunately, the agents are easy to apply, but if this is not done adequately, the cockroaches can develop resistance to the poison. Always follow the instructions on the bottle. If you cannot fight the cockroaches, you should switch between several different types of poison. Additionally, you can contact a professional pest controller who typically uses a paste or gel to control the pest. These agents contain both food and poison, where the cockroach will die after ingesting the agents.
"Pests in House and Home"
"Bed Bugs - Bites, Stings and Itches"
"Food Pests"
"Husets dyreliv" (Insects Around the House - Only danish)
"Skadedyr i træ" (Timber Pests - Only danish)
"Stuefluen" (Common Housefly - Only danish)