Denmark´s fauna is rich in insects; both domestic species as well as more exotic ones. Here, you can read more about the species of cockroach that are normally found in Denmark. The sections are listed in order of how frequently they occur. The four most common species are described below and instructions are given on what to do if you run into these insects. Sections on dissemination, living conditions and reproductive methods are also included in this presentation, as this is important if you want to prevent the spread of cockroaches.
Cockroaches eat any type of food.
All cockroaches have wings they can extend. A few species, like the Asian cockroach and the brown cockroach, can use their wings to fly. The domestic species can only spread their wings and glide through the air.
There is no actual Danish cockroach as such, but species such as the invasive German cockroach, Oriental cockroach, lesser cockroach and forest cockroach are now considered ‘Danish’ species.
Houses, flats, restaurants, hotels and many other types of building can become infested with cockroaches. The cockroaches move from property to property carried on luggage, transported with food and via piping in older premises.
Cockroaches are not actually dangerous as a species. Their relatively soft mouth parts cannot bite through human skin. However, cockroaches can carry and spread diseases such as salmonella, dysentery and typhoid fever. Furthermore, their droppings have an unpleasant smell when they occur in quantities.
Getting rid of cockroaches
If you need to get rid of a cockroach infestation, the most important thing is to make their living conditions intolerable. Cockroaches need water, heat, vegetable matter, and cracks and small hollow spaces in which to hide. So by removing these, you´ll get rid of them. Eliminate what they need to survive. We´ll explain the methods you can use to do this later on in this presentation.
The German cockroach
The German cockroach is the most common domestic species.
It is a yellowish-brown and has two dark stripes on its pronotum. It grows to a length of between 12 – 15 mm and its well-developed elytra (forewings) cover the entire hind part of their abdomen. Beneath their elytra, are the cockroach´s posterior wings that are fully functional, although it does not use them. The German cockroach prefers to run or climb.
After mating, the female lays her eggs in special brown egg capsules, and each capsule contains 30-40 nymphs. Most cockroaches lose the egg capsule following oviposition (egg-laying), but not the German cockroach. The female carries the egg capsule right up until the small wingless nymphs are ready to swarm out.
The German cockroach prefers heated rooms, at temperatures of between 25-33 degrees, and also needs moisture which it finds in kitchens or wet rooms.
The brown-banded cockroach
The brown-banded cockroach is said to originate from Africa, but over the years it has spread to all tropical and subtropical areas. In the 1970s, we also had some of them in Denmark, but it is not nearly as widespread as the German cockroach.
The brown-banded cockroach thrives in temperatures below 25 to 30° and, unlike other cockroaches, it can make do with fairly dry environments, such as the living room or the bedroom where you will normally find it behind furniture or between cracks in skirting boards.
The egg capsules of the brown-banded cockroach contain 10 to 20 eggs which it lays in cracks and crevices. A female can lay anywhere between five and 20 capsules during its lifetime. At about 20°, it takes a couple of months before the nymphs leave the capsules. The fastest development happens at 24 to 30°. At these temperatures, they take about six weeks to develop.
The American cockroach
As the name suggests, this type of cockroach is very common in America. From time to time, it is imported with goods from overseas countries. The American cockroach thrives in an environment with high humidity and in very hot environments.
Should you run into the American cockroach in Denmark, you won´t be able to mistake it for anything else, as it is pretty big. A fully-grown cockroach is between 2.8 and 4.4 cm in length. The American cockroach is the largest species of cockroaches that are found in Denmark.
The German cockroach is reddish-brown in colour and shiny. Its body is flat with long antennas. It lives indoors in kitchens, cellars, outlets, lengths of pipe and so on.
It is active during the night, and during the day, hides in cracks and crevices, usually in the vicinity of sources of heat such as pipes, motors and other electronic appliances.
This dark species is not a typical sight in Denmark, but if you run into it you will find that it is much larger than the Nordic members of the same species. What´s more, it is less agile and moves much more slowly. One characteristic of this type of cockroach is that its elytra only cover about ¾ of the hind part of its abdomen.
It is perhaps surprising that it is not seen more commonly in these latitudes as it thrives better here than both the German and the brown-banded cockroach. Its optimum temperature is about 20° to 25° and the optimum environment is humid and dark – as with other species, the Oriental cockroach is also active during the night.
The Oriental cockroach can grow to lengths of between 25-30 mm, and is thus quite a bit larger than the domestic species. A cycle of oviposition consists of the female carrying eggs that are located in a capsule that is fastened to the hind part of its abdomen for a few days. After this, the capsule is dropped and after about 60 days, they hatch. The nymphs go through several stages during a period of up to 9 months until they reach their fully-grown stage.
How cockroaches live
Cockroaches lurk behind refrigerators!
Cockroaches live where it is dark, and they prefer a humid environment. This is why cellars, outbuildings and bathrooms are good places for cockroaches to live, mate and produce even more cockroaches. However, this does not mean that cockroaches will not seek out drier environments.
Cockroaches can wander far and wide through a property, and they have no trouble migrating at night. This allows them to find new places to live that may provide more nourishment than where they came from. Scent trails and pheromones summon other cockroaches, and this is normally done through secretion in their droppings. In this way, they follow each other’s trails, establishing themselves in new areas should they prove to be a lucrative source of food.
Cockroaches breed by laying eggs. It takes anywhere from 2 to 6 months for cockroaches to develop into adults, depending on whether the environment they are in is warm or cold. The optimum temperature for cockroaches is about 25 degrees, but they seek cool, dark places to hide away in during the daytime. Cockroaches come out at night, when they become active, search for food and breed.
Night-time activity, omnivorous and spreader of diseases
Cockroaches will eat almost anything. They are active during the night and hide in cracks and crevices during the day, where they can often be found behind kitchen appliances, near sinks, behind heating pipes and so on.
Cockroaches can spread diseases and bacteria including the following:
- Typhoid fever
The risk of infection is higher in homes with elderly people, children or people who are already weakened by another disease.
Cockroaches and foods
Cockroaches are definitely a pest when it comes to foods. They leave droppings behind everywhere on the foods they eat, and also contaminate other foods as they move around inside drawers and cupboards.
It is important to store all of your food securely, preferably in plastic containers, so the cockroaches are unable to reach your food. If you have a larder or a cool cellar, you will find it more difficult to get rid of cockroaches. This is both because food is readily-accessible here, and because cockroaches prefer dark, humid environments. If you notice that areas with foods are infested, it is important to react immediately, as this is something that can rapidly get out of hand and develop into a situation that is difficult to get under control again.
Newer properties are not infested with visits from hungry cockroaches as often as older premises. This is because it is harder for cockroaches to enter newer properties due to modern building regulations requirements regarding the density of building materials. Access is easier for a cockroach to live in an older house with cracks and crevices where there are water pipes, electrical supply lines and the like. Cockroaches do not need much in the way of space to get in.
Climate change may bring southern European cockroaches to Denmark. The question is whether the Nordic climate is changing in a way that makes the living conditions for the large southern cockroaches better at these latitudes?
We do not yet know how much the temperature needs to rise before cockroaches from the South start migrating here. But we mustn’t close our eyes to the fact that if living conditions for these large cockroaches become optimal in Denmark, then they will soon show up here.
As it hasn´t yet reached that stage, we can rejoice in the fact that we only have to fight the smaller species of cockroach that are more easily dealt with. That isn´t to say that Danish cockroaches are welcome visitors – it is merely pointing out that at least the cockroaches in Denmark are not as large as their southern counterparts. But, of course, cockroaches in Denmark are still a pest, and are both harmful and a nuisance.
Memo about cockroaches:
- There are only the small species of cockroaches in Denmark, the larger ones are found in Southern Europe
- Cockroaches are omnivorous
- Most cockroaches are active during the night
- Avoid making cockroaches resistant to poison
Good advice on cockroach pest control
If you want to get rid of cockroaches, here is some good advice.
If your pest control against cockroaches is sloppy, they´ll suss it out. Sloppy pest control often means that cockroaches simply become resistant to the insecticide used against them. If the insecticide is not distributed properly, many of them will survive the first attack and survive to go on reproducing. It will be the same with the next generation and the next – by which time they will have become immune to the insecticide.
When tackling cockroach infestations, you need to be careful about where you distribute the insecticides and pinpoint the exact locations cockroaches frequent. You can be sure they won´t be anywhere near where you have sprayed or left your insecticides. To avoid this, you need to distribute the poison in carefully-selected locations, so you kill the entire generation of cockroaches and prevent any surviving cockroaches from developing resistance. Should a few survive, they will find it hard to establish themselves again, and the remaining few will be easy to get rid of.
Cockroaches, nymphs and egg capsules
Cockroaches are intelligent insects and will figure out what´s going on, if you make a wrong move in your attempts to get rid of them. This is why you must determine exactly where they are, before you begin. In other words, you need to locate all the cockroaches and their nests. Then you can take action, and remember to make sure that the pests have to walk through the insecticides. It is important that you use the correct dosage and don´t just chuck it everywhere, as there needs to be a pattern.
You could also try using different insecticides in your fight against the cockroaches. This way, the cockroaches are less likely to become resistant to your insecticide. Cockroaches can be removed once and for all if you have a professional approach to the infestation.
Do you need pest control against cockroaches?
Absolut Skadedyrsservice has many years of experience in exterminating cockroaches. Our extensive experience means we can swing into action and begin ridding your home of cockroaches within 24 hours. We offer repeated treatments, so you can be sure you have gotten rid of the cockroaches – once and for all.
If you are a business-owner, it is even more important to react immediately, as cockroaches contaminate food. Call us at any time of day .
We have many years of experience in the field of pest control – and cockroaches are just one of the areas of pest control we specialise in.
Call us today and be pest-free tomorrow!
We keep hotels, food suppliers, private properties and rental properties free of cockroaches throughout Copenhagen and the surrounding areas.
If you have a pest problem, we can help you.
Contact Absolut Skadedyrsservice
At Absolut Skadedyrsservice, we are the professionals when it comes to pest control – we eradicate any type of cockroach and many other insects.
Our products are approved by The Danish Environmental Protection Agency and are odourless, so you can already go back into your house just 10 minutes after the treatment has been done.