Information and Advice About Cockroaches

Fact Sheet: Cockroaches  

German cockroach - Blattella germanica

Adults are about 17mm long and light brown except for the shield behind the head, which is marked with two dark stripes, running lengthwise down the body. Immature
insects (nymphs) are wingless and nearly black with a single light stripe running down the middle of the back. Egg capsules are light tan in colour. Each female may produce four to six egg cases during her lifetime, each containing 30 to 40 eggs. Eggs hatch in 28 to 38 days, and nymphs develop in 40 to 125 days. The German cockroach produces more generations per year (three or four) than any other cockroach, and only a few individuals are needed to develop into troublesome infestations.  

Oriental cockroach – Blatta orientalis

Usually dark reddish brown in colour, adults are about 25mm long and nymphs resemble adults except that they are wingless. Unlike other cockroaches, the Oriental cannot climb up smooth surfaces.  

This species generally lives in moist areas, but can survive in dry areas, with access to water. They prefer cooler temperatures and thus are common in basements, boiler
houses and walkways adjacent to buildings, and breed well in unventilated crawl spaces or basements with high humidity. Adults can live up to one year, during which
females produce an average of 150 young. This cockroach prefers to feed on starchy foods but will adapt to survive.

American cockroach - Periplaneta americana

Adults are 25-40mm long, reddish or dark brown, except for a tan or light yellow band around the shield behind the head, and have wings capable of flight. Often found in damp sewers and basements, in heating ducts, etc., American
cockroaches can be transported into homes in boxes from infested premises. Egg capsules protrude from the body before being deposited prior to hatching. One egg capsule is formed each week until six to 14 have been produced.   

Brown-banded cockroach – Supella longipalpa

Adults are about 15mm in length, and similar in appearance to the German cockroach, but with two yellow-brown bands running across the body. These cockroaches may be found in all parts of the home, favouring hiding places off the floor. They prefer a warmer environment than German cockroaches and are therefore less common in the UK.  

We recommend an integrated approach involving the use of:
• cockroach traps to monitor and assess the extent of an infestation, 
• insecticidal baits and well targeted use of 
• residual insecticidal sprays, 
• insecticide powders (or chemical-free desiccant dust), as well as 
• Insecticidal lacquer as a long-lasting barrier against ingress
 
Please note that as cockroach infestations tend to be concentrated on food preparation areas, care should be taken in selection of food-safe or even organic chemicals, such as those included in our cockroach kits. For American and Brown-banded species, the use of fumigants may considerably enhance the programme. 
 
Images from Wikimedia Commons (from top): Copyright © 2007 David Monniaux; Gary Alpert; Saphan; Insects, their way and means of living, R. E. Snodgrass  (U.S. Dept of Agriculture)