Advice
Cockroaches in the UK: how to identify and get rid of them
You get rid of cockroaches in three steps: take away their food, water and hiding places, put cockroach traps as close as possible to where you see them, and call in a professional pest controller for a large infestation. Cockroaches come out at night and hide in warm, dark cracks during the day. If you see one running about in daylight, the infestation is usually bigger than you think.
In this article
- Remove the source. Clear up crumbs and grease, keep food in closed containers and fix leaks.
- Set traps. Put a cockroach trap in every spot where you see cockroaches. The catch shows you where they run.
- Get help. If they keep coming back, or the neighbours in your block of flats see the same, call a professional pest controller.
How do you recognise a cockroach?
By its flat, oval body, long antennae and quick movements; cockroaches dart away as soon as the light goes on. Other clues are small black droppings, empty egg cases and a musty smell in cupboards and corners.
What are the signs of a cockroach infestation?
Droppings that look like ground black pepper or coffee grounds, empty egg cases and shed skins in cupboards and cracks, and cockroaches that you see at night. Mouse droppings are larger and elongated, like a grain of rice, so the droppings also tell you whether you have cockroaches or mice. Seeing cockroaches in daylight is a sign of a larger infestation.
What types of cockroach live in homes?
Four species live indoors: the German cockroach, the Oriental cockroach, the American cockroach and the brown-banded cockroach. Outdoors you also find wood cockroaches, which now and then come inside by accident. The sizes below are those of the Dutch Knowledge and Advisory Centre on Animal Pests (KAD).
| Species | Length | Colour | Does it fly? |
|---|---|---|---|
| German cockroach | about 1.1 to 1.5 cm | straw yellow to light brown, two black stripes on the shield behind the head | has wings, hardly ever flies |
| Oriental cockroach | about 2.1 to 2.8 cm | reddish brown to blue black | no |
| American cockroach | about 2.8 to 4.4 cm | glossy reddish brown with pale yellow markings | short gliding flights in warm weather |
| Brown-banded cockroach | about 1 to 1.5 cm | two dark brown bands across the body | flies up easily |
| Wood cockroaches (Ectobius) | about 0.5 to 1.3 cm | each species has its own marking behind the head | some species fly well |
How to tell the species apart is explained in German or Oriental cockroach?
What do cockroach eggs and baby cockroaches look like?
You will not see loose eggs: cockroaches lay their eggs in an egg case. According to the KAD, a German cockroach egg case holds about 30 eggs, and the female carries it on her abdomen for 3 to 5 weeks. The Oriental cockroach carries its egg case for only a few days. Baby cockroaches (nymphs) shed their skin several times before they are adult; Oriental cockroach nymphs are very dark. Empty egg cases and shed skins in cupboards and cracks are a sign that cockroaches are living in your home.
Can cockroaches fly?
Most cockroaches in the home cannot fly or hardly ever do. The German cockroach has wings, but according to the KAD it only flies at very high temperatures. The Oriental cockroach does not fly. The American cockroach makes short gliding flights in warm weather and the brown-banded cockroach flies up easily. A cockroach that flies in through an open window in summer may well be a wood cockroach.
What attracts cockroaches and how do they get into your home?
Cockroaches are attracted by food, warmth and moisture, which is why they follow people. They come in with boxes, shopping or second hand appliances, or move from flat to flat through the service shafts in a block. Favourite hiding places are kitchen cupboards, the space under the sink and behind the fridge, cellars and storerooms.
What do cockroaches eat?
Almost anything: crumbs, grease, sugar, fruit and vegetable scraps, pet food and rubbish, and if they have to, paper, glue and dead insects. A little grease behind the cooker or a full pet bowl is enough for them. Water matters just as much: a cockroach can survive for months without food but for much less time without water (Penn State Extension). So remove moisture too, such as a dripping tap or a wet dishcloth.
How fast do cockroaches breed?
The German cockroach breeds fast. According to the KAD, a female produces seven egg cases of about 30 eggs on average, and a young cockroach can breed itself after one and a half to three months, depending on the temperature. In a warm kitchen, a small group can grow into an infestation within a few months.
Are cockroaches dangerous, and do they bite?
They can be a health risk. Cockroaches can spread bacteria such as salmonella onto food and kitchen equipment, and their droppings and shed skins can trigger allergies. Bites have only been reported in very heavy infestations (German Environment Agency, University of Florida).
What should you do if you see one cockroach?
First check whether it is a pest species. A single light brown cockroach in summer, near an open window, is often a wood cockroach: simply put it back outside. If you see a cockroach in the kitchen or bathroom, put a trap in that spot to find out whether there are more.
Is it OK to kill a cockroach?
Yes, but clean it up straight away. A female German cockroach carries her egg case on her abdomen for a few weeks. Killing one cockroach will not solve an infestation: that lives in the hiding places.
How do you get rid of cockroaches?
By removing their food, water and hiding places and setting traps where you see them. In the Super Ninja Cockroach Trap the lure is in the glue: cockroaches walk in and get stuck. Put it as close as possible to the problem, in the kitchen, the bathroom, the food cupboard or the cellar, and replace it when it is full or after 3 months. The catch shows you where they run and whether the numbers drop. A large infestation, for example in a block of flats, needs a professional pest controller.
What keeps cockroaches away?
Cockroaches stay where they find food, water and somewhere to hide. Take those away and a cockroach has no reason to be in your home. Also seal gaps around pipes and skirting boards, so they have fewer places to hide. Bleach down the drain or strong smells do not remove food, water or hiding places, and no research is known that shows they get rid of cockroaches.
How do you keep cockroaches out?
With five habits that take away their food, water and hiding places:
- Keep the house clean. Remove crumbs and grease regularly, also behind the fridge and under the cooker.
- Store food properly. In containers with a lid; fruit and vegetables in the fridge or covered.
- Keep rubbish covered. Use a bin with a lid and empty it regularly.
- Keep it dry. Ventilate the cellar, keep the cupboard under the sink dry and fix leaks.
- Check what you bring in. Look through boxes and second hand appliances before you bring them indoors, and do not leave pet food out.
Is a small light brown cockroach in summer an infestation?
Often not. If you see one or two light brown cockroaches near a window in summer, it is often a wood cockroach. It lives outdoors, does not breed indoors and is not a pest (KAD). How to recognise one is explained in Wood cockroach in the house.
Sources: Dutch Knowledge and Advisory Centre on Animal Pests (KAD), German Environment Agency (Umweltbundesamt), Baden-Württemberg State Health Office (Landesgesundheitsamt), University of Florida IFAS and Penn State Extension.
