Cockroach eggs: what they look like and what to do

What do cockroach eggs look like?

Cockroach eggs sit together in an egg case (ootheca): a firm, elongated capsule that looks like a tiny purse or a bean, with a seam along its length. You do not see the eggs themselves. The egg case of the German cockroach is light brown and about half a centimetre long, with the eggs in two rows (Penn State Extension).

An empty egg case has split open along the seam. Empty egg cases and shed skins in cupboards and cracks are a sign that cockroaches are living in your home.

How do you identify the egg case of each cockroach species?

You identify the species mainly by the colour, the size and the place where you find the egg case. These are the four species that live indoors:

• German cockroach: light brown, about half a centimetre long, with around 30 eggs. The female carries the case on her abdomen for 3 to 5 weeks (KAD). So you often see it on the cockroach itself.
• Oriental cockroach: around 16 eggs. The female carries the case for 5 days at most and then leaves it in a sheltered spot (KAD).
• American cockroach: dark brown to black, about 8 to 12 millimetres long, with 16 eggs on average. It is deposited in a hidden spot after 1 to 6 days, often glued in place (KAD, Penn State Extension).
• Brown-banded cockroach: 16 eggs on average. The female sticks the case down after 1 to 2 days, often on the inside of furniture (KAD).

Not sure yet which species you have? Read German or Oriental cockroach.

Where do cockroaches lay their eggs?

Cockroaches leave their egg case in a warm, dark and sheltered spot close to food and water. The German cockroach only does so shortly before the eggs hatch, in cracks and crevices (KAD, Penn State Extension).

Look in these places with a torch:

• behind and under the fridge, the dishwasher and the cooker
• in the cupboard under the sink and along pipes
• in the joints and corners of kitchen cupboards and behind the skirting board
• in the cellar, the airing cupboard and around the boiler
• on the inside and underside of furniture (brown-banded cockroach)

How long do cockroach eggs take to hatch?

That depends on the species: from about 4 weeks for the German cockroach to 2 to 3 months for the Oriental cockroach. The warmer it is, the faster it goes.

• German cockroach: about 4 weeks after the egg case is formed (Penn State Extension).
• American cockroach: 5 to 7 weeks (KAD).
• Brown-banded cockroach: about 37 days at 30 degrees Celsius (KAD).
• Oriental cockroach: 2 to 3 months after the case is deposited (KAD).

So an egg case that has already been deposited can still hatch weeks later. That is why you sometimes see baby cockroaches again when the adults are already gone.

What do baby cockroaches look like?

Baby cockroaches look like the adults, but they are smaller and have no wings. According to the KAD, German cockroach nymphs shed their skin six times in about a month and a half; below 25 degrees Celsius it takes longer.

If you see small, wingless cockroaches, they are breeding in your home.

What should you do if you find a cockroach egg case?

Remove the egg case straight away: pick it up with a piece of kitchen roll, put it in a bag, tie the bag shut and put it in the outside bin. Do not leave it in the kitchen bin.

Then keep looking in the same spot and in the cupboards next to it. Clean the area, remove crumbs and grease and keep it dry. The full step by step plan is in our guide how to get rid of cockroaches.

Does one egg case mean you have a cockroach infestation?

One egg case means that at least one female is or has been in your home, and about 30 young hatch from a single German cockroach egg case. According to the KAD a female produces seven of them on average. So do not wait.

Only wood cockroaches are an exception: they live outdoors and do not breed indoors (KAD). Read more in wood cockroach in the house.

How do you know whether cockroach eggs are still hatching?

You can tell with a cockroach trap in the spot where you found the egg case. The trap catches the cockroaches that walk into it and so shows you where they are and whether their numbers are going down.

Leave the traps in place for a few weeks and check every week what is inside. If you catch small, wingless cockroaches or a female with an egg case, young are still being added. A trap does not catch an egg case itself: you remove that by hand.

When should you call a pest controller?

Call a professional pest controller if you find egg cases in several places, see cockroaches during the day or still catch young cockroaches after a few weeks. In a flat or terraced house they are often next door as well; in that case report it to your landlord or managing agent.

Sources: Dutch Knowledge and Advisory Centre on Animal Pests (KAD), species pages German, Oriental and American cockroach, brown-banded cockroach and wood cockroaches; Penn State Extension, German Cockroaches, Oriental Cockroaches and American Cockroaches; Baden-Württemberg State Health Office, cockroach information (2019).