Pest Of The Week – Cockroaches

Most people find cockroaches repulsive, and they are usually thought to be a sign of poor hygiene and insanitary conditions; however, they can actually infest even the cleanest home or business.

There are over 3,000 species of cockroach, but the two main types found in the UK are the German Cockroach (Blattela germanica) and the Oriental or Common Cockroach (Blatta orientalis). There are four times the number of Oriental Cockroach infestations as there are infestations of German Cockroaches; however, German Cockroaches reproduce more rapidly than the Oriental Cockroach.

Cockroaches share many of the same characteristics in that they lay their eggs in an eggcase or ‘ootheca’. Young cockroaches are usually known as ‘nymphs’.

Cockroaches are true omnivores and will feed on literally anything they can find. Cockroaches are nocturnal creatures and tend to come out at the same time every night.

Cockroaches are carriers for many diseases including salmonella, gastroenteriris, dysentery, tuberculosis, tapeworm and hookworm.

Which type of cockroach do I have?

The bottom line is that it doesn’t really matter which type of cockroach you have as the treatment for both is pretty much the same. However, the main differences are described below: German Cockroaches are 12-15mm long and brown in colour with two darker stripes across the thorax. They breed throughout the year, producing eggcases (oothecae) containing around 140-320 eggs.

Oriental or Common Cockroaches are larger than the German at 25-30mm in length and are dark brown to black in colour. They lay batches of eggcases containing around 80-160 eggs.

Where are cockroaches found?

As they favour hot and humid conditions, cockroaches are often found in kitchens, laundries and food manufacturing plants. Their flattened shape allows them to penetrate into even the smallest cracks and crevices.

Oriental Cockroaches can also be found in cooler areas such as basements and underground ducts and even outside on rubbish tips.

German Cockroaches have pads on their feet which allow them to climb up shiny or polished surfaces, so they are often found above floor level. Oriental Cockroaches do not have these footpads so tend to be found at or near ground level; however, they are able to climb up external brickwork using the claws on their feet.

Unlike the German Cockroach, which tends to remain in groups, the Oriental Cockroach is usually widely dispersed.

How do I know if I have cockroaches?

As cockroaches are nocturnal, people sometimes don’t realise they have a cockroach infestation. The main sign of an infestation is an unpleasant oily smell and the presence of brown, irregular marks on floors or surfaces, particularly near wall/floor junctions, which are the liquid excreta left behind by cockroaches. Another good method of detection is sticky Cockroach Traps, which can be left out overnight and therefore used to monitor activity over a number of days.

How do I get rid of cockroaches?

Cockroaches can live up to three months without food and a month without water. They prefer warm and humid environments but are also able to withstand freezing temperatures, which makes them difficult to eradicate once they have infested an area.

The first thing to do is establish the scale of the infestation, which can be done by carrying out a thorough inspection of the affected area, paying particular attention to inside kitchen units, under sinks, behind electrical goods, between tiles and floorboards etc. Sticky cockroach traps with scented attractants are an excellent method of helping identify the locations of cockroach harbourages and estimate the numbers involved. They can also help trap and kill cockroaches.

Once the areas of infestation and the level of activity have been established, the best way of getting rid of cockroaches is with a spray treatment using residual insecticides. These should be administered around the edges of a room at wall-floor junctions, which are the cockroaches’ main travel routes, around pipes and drains, and any other cracks and crevices where they may be harbouring.

In addition, insecticidal powder can be applied behind cupboards, skirting boards, under work surfaces, and around power sockets where a spray cannot be used. Insect aerosol ‘lacquers’ such as Insectrol Spray can also provide a good means of control by forming long-lasting barriers around affected areas.

For a full scale comprehensive cockroach treatment, insecticidal smoke bombs and fumigating foggers can also be added. These cockroach killing products work by releasing a smoke or gas in to the air, thereby flushing out cockroaches from hard to reach or inaccessible areas.

To further aid in the eradication of cockroaches, we would advise that customers ensure that all foodstuffs are stored in sealed containers, that any cracks or crevices are filled (where possible), any damp or hygiene problems are remedied, floors and worksurfaces are regularly cleaned and rubbish bins frequently emptied.


If you suspect you have a cockroach infestation in Edinburgh, Glasgow, Aberdeen, Dundee or Perth, call GRAHAM pest control today and we could help.