The signs of cockroaches are small dark droppings collecting in corners, cupboards and behind appliances, brown egg cases tucked into cracks, pale shed skins, damage to food packaging, a strong unpleasant smell once numbers build up, and the insects themselves, usually seen scattering when a light goes on at night. Cockroaches are nocturnal, so most people find the evidence they leave behind long before they see a live one, and any cockroach seen out in daylight is worth taking seriously.
Which signs you find, and where, depends on which cockroach you have. The two common in UK homes and businesses behave very differently. The German cockroach is small, 10 to 15mm long, light yellowish brown with two dark stripes just behind the head, and lives in warm, humid spots behind cookers, fridges and dishwashers. The Oriental cockroach is larger, 20 to 24mm, shiny black or dark mahogany, and prefers cool, damp places such as drains, cellars and the voids under floors. Knowing which one you are looking at tells you where to search and how quickly the problem is likely to grow.
Droppings
Droppings are usually the first sign anyone notices. They are small, dark and scattered, often described as looking like ground pepper or coffee grounds, and they build up where cockroaches hide and travel, such as the back corners of cupboards, along shelf edges, in drawer runners, around door hinges and on the floor behind appliances. Larger cockroaches leave larger droppings, so bigger, more cylindrical droppings near a drain or in a cellar point towards the Oriental species.
Like rats, cockroaches tend to stick to the same routes and the same hiding places, so a concentration of droppings in one spot is more useful than a scattering across a worktop. It marks a harbourage, and a harbourage is where the treatment needs to go.
Egg cases
Cockroach eggs are laid inside a hard, brown, purse shaped case called an ootheca, and finding one is a clear sign of a breeding population rather than a single stray. According to the British Pest Control Association's guide to cockroaches, the two species handle their egg cases in very different ways.
- The German cockroach carries its egg case attached to its body until the young are almost ready to hatch, and each case usually releases 30 or more nymphs. You are more likely to see a female carrying one than to find one lying loose.
- The Oriental cockroach drops its egg case, about 13mm long, in a dark crevice well before it hatches, and each releases around 16 to 18 nymphs. Loose egg cases behind skirtings, in cupboards or near pipework point to this species.
The speed difference matters. German cockroaches can go from egg to adult in a matter of weeks, while the Oriental species takes six months to a year, which is why a German infestation can turn from a few sightings into a serious problem far more quickly.
Shed skins
Young cockroaches look like smaller versions of the adults, and they shed their skins five or six times as they grow. The empty skins are pale and papery and collect in the same hiding places as the droppings. Finding skins of different sizes tells you the population is breeding and growing, rather than being a single insect that came in with a delivery.
Smell and damage
A large infestation produces a strong, musty, oily smell that lingers in kitchens, store rooms and cupboards, and some people notice it before they have seen anything at all. Cockroaches also chew into packaging, particularly card and paper, and leave droppings among stored food.
They are a genuine health concern. Cockroaches are known to carry organisms that cause food poisoning, including salmonella, and they spread them by moving between drains, waste and food preparation areas. Any food you think a cockroach has been in contact with should be thrown away.
Where to look, species by species
Search with the species in mind.
- German cockroaches favour warmth and humidity. Look behind and beneath cookers, fridges, freezers and dishwashers, especially near their warm motors, under the sink, inside the kickboard space under kitchen units, around the boiler and in cupboards close to hot pipes.
- Oriental cockroaches favour cool, damp conditions. Look around drains and gullies, in cellars and basements, under the bath, behind the toilet, and anywhere a slow leak keeps the floor damp.
- Both species turn up around heating ducts, boiler rooms and pipe runs in larger, centrally heated buildings.
Cockroaches only come out to forage in the dark and are back under cover within seconds of a light going on, so a check with a torch an hour or two after the kitchen lights have gone off will show you far more than a search in daylight. The torch shows you not just whether they are there but which way they run, and that leads you straight to the harbourage. Sticky monitoring traps placed along the backs of cupboards and behind appliances do the same job overnight, and while they will not cure an infestation, they will tell you how widespread it is.
Older property needs particular care. Many terraces in Folkestone and Hythe have suspended timber floors over voids that run along the row, and those cool, damp spaces, together with old drainage, suit Oriental cockroaches well. So in an older house the drains and the space beneath the floor are worth checking as well as the kitchen cupboards.
Signs to watch for in food businesses
The coast from Hythe and Folkestone through to Dover and Deal has plenty of takeaways, cafés and restaurants, and commercial kitchens offer cockroaches everything they need, with warmth, moisture, food and plenty of equipment to hide behind. The Food Standards Agency's Safer Food, Better Business pack lists the signs staff should know, which are eggs and egg cases, moulted skins, the insects themselves and droppings, and it is clear that anyone who sees signs of an infestation should call a pest contractor immediately.
For a kitchen, the cost of missing the early signs goes well beyond the treatment, which is why regular pest control is worth it for restaurants and other food businesses. A scheduled visit is a chance to pick up the first droppings or egg case behind a fryer before a customer or an environmental health officer does.
Why one cockroach is rarely the whole story
Because cockroaches hide all day and forage at night, the one you happened to see is almost never the only one. A single sighting, especially indoors and especially at floor level in a kitchen or bathroom, is a reason to look for the other signs rather than a reason to relax. Whether you should book pest control for a single cockroach comes down to where you saw it and what else you can find, and in a kitchen or bathroom the answer is usually yes.
Shop bought sprays tend to make things worse rather than better. They kill the few cockroaches they reach, while the rest scatter deeper into wall voids and appliances, which spreads the infestation and makes it harder to find. The BPCA recommends a professional for any cockroach infestation, and sticky traps for monitoring only.
What treatment involves
A professional inspection starts by confirming the species and mapping where the cockroaches are living, using the droppings, egg cases and skins described above. Our cockroach control then uses professional gels, sprays and bait stations placed in the harbourages and along the routes, so that the cockroaches carry the treatment back to where they hide. In more severe cases a follow up visit may be needed, particularly with German cockroaches, to catch the young that hatch from egg cases after the first treatment.
If you have found the signs
If you have found droppings in a cupboard, an egg case behind the cooker or a cockroach running for cover when the light went on, it is worth acting now rather than waiting to see more, because the numbers you can see are always a fraction of the ones you cannot.
At Cinque Ports Pest Control we are a family run business based in Dymchurch, with more than twenty-five years in the trade behind us, and we deal with cockroaches in homes and businesses, food businesses included, across Romney Marsh, Ashford, Canterbury, Folkestone, Hythe, Dover and Deal. If you have found something and want to know what it is, get in touch and we will take a look.
Cinque Ports Pest Control Ltd is a family run business based in Dymchurch, Romney Marsh. We are BPCA members, Kent County Council Trading Standards approved, TrustMark registered, SafeContractor approved and CRRU supporters.
