The Cockroach (Order Dictyoptera) are commonly associated with human habitation. Most cockroaches are drab brown in appearance and predominantly tropical. Some species have occupied the artificial environments created by man, who is largely responsible for their spread particularly in restaurants, kitchens and hotels. Strongly linked with disease transmission and public distaste over their presence indoors.


There are good reasons to control cockroaches (Blattaria):

  1. A disgusting odour is associated with cockroaches often referred to as a ‘roachy’ smell, which is a sure sign of contamination. They often damage or stain a wider variety of foods, fouling foods they do not consume. Their presence results in considerable loss of business and goodwill.
  2. Cockroaches can carry diseases of public health importance e.g. Salmonella
  3. Presence can cause public annoyance and psychological distress to members of the public.
  4. They damage many items other than foods e.g. pictures, books&leather goods.
  5. An important consideration in terms of employee morale as few employees will tolerate their presence in the workplace.

They are nocturnal and scavenge over a wide area. Life-cycle follows an incomplete metamorphosis, the female produces egg cases containing a variable number of eggs. Adults are omnivorous, they need a supply of drinking water or foods with a high-water content. They groom themselves to remove dust and dirt. The mouthparts serve a biting, chewing and licking function. The mandibles are strong and toothed. The gizzard contains an armature for masticating food. Cockroaches and their faces may cause allergic reactions to amongst sensitive individuals e.g. asthmatics. Exposure may result from ingestion or through inhalation of materials derived from cockroaches in airborne dust.


The common oriental cockroach prefers less humid and cooler conditions (22-27°c). A major pest in buildings such as cellars, boiler rooms, basements, bakeries and bars. Occasionally found outdoors in refuse tips. The German cockroach prefers warm moist conditions (25-30°c) and common pest in heated buildings e.g. galleys, larders, store rooms, kitchens and restaurants.


Careful building surveys are needed to establish the true extent of an infestation. Visual night inspections and flushing with a pyrethrum spray is required with observation of physical signs e.g. egg cases, faecal spotting and strong odour characteristic of heavy infestations. A thorough systematic, integrated approach to cockroach infestations is recommended with the use of traps as monitoring devices followed by species identification.


Gel bait treatments will predominate, dust formulations for inaccessible areas and residual sprays on the periphery of infestations. Good housekeeping is essential to effectiveness of treatment especially removal of food residues and general cleaning of surfaces. Broken tiles should be repaired or replaced, and any possible areas of harbourage should be sealed with mortar, builders caulk or suitable fillers to the operating environment.

Mervyn WalshBA(Hons), HDip.EnvMgt, MRSPH

Field Conservation Biologist