A to Z of Pests

Seasonal Pest

Cockroaches

Blatta orientalis

Blatta orientalis

Several species of cockroaches may be found in houses and commercial buildings throughout Britain. The Oriental cockroach (or common cockroach), Blatta orientalis and the German cockroach, Blatella germanica, are by far the most common.

Appearance

The Oriental cockroach is a flattened insect, 20-30 mm in length, and shiny reddish black. The male has short wings that do not reach the tip of the abdomen and the female has no obvious wings – they are reduced to very small lobes.

The German cockroach is yellowish-brown with two dark brown stripes on the thorax. Adults are 10-15 mm long and both males and females have fully developed wings.

Life Cycle & Biology

German cockroaches are more common where high temperatures prevail; Oriental cockroaches prefer drier, cooler environments, and are sometimes found outdoors, especially on rubbish tips. Both species hide during the day in cracks and crevices, and in kitchen equipment, and their presence may go unnoticed for some time.

Eggs are laid in oothecae (egg-cases) which are carried by the female. Those of the Oriental cockroach are deposited in sheltered crevices when fully formed. The German cockroach carries her egg-case until the young are ready to hatch.

The life-cycle has three stages: egg, nymph and adult.

Damage

Cockroaches feed at night on a wide range of stored foods and they will sometimes damage books, pictures, leather goods etc. The amount of food taken is usually insignificant; most of the damage caused is by fouling with liquid excreta and by tainting with a characteristic “roachy” smell.

Control

Cockroaches can be controlled with insecticidal aerosol sprays and dusting powders. It is important to find and treat daytime harbourages, fir it is here that the insects will pick up most of the insecticide. Treatment should be repeated after about 10 weeks (Oriental cockroach) or 6 weeks (German cockroach) to ensure that all newly-hatched nymphs are killed.

Food stuffs infested with cockroaches should always be destroyed. All food debris in difficult to reach places should also be disposed of.

Think you have a problem with Cockroaches? Phone us on: 800 914478