Introduction
There are many species of cockroaches. They are widely distributed throughout the world. Two species are common in this part of the world, namely: Blatta Orientalis (Oriental Cockroach). They shall be discussed under the following sub-topics:
- Identification
- Life history
- Mode of life
- Medical importance
- Control measures.
Identification
Cockroaches are large reddish brown insects, rather flattened from above downward and elongated. An adult cockroach measures about 4 cm in length and has wings, but these are folded closely to the back and will not be noticed unless carefully looked for. Cockroaches are vectors and they are also insects.
Their body is divided into three parts, namely: the head, thorax and abdomen. On the head, they have the compound eyes, very long antennal and the head and well developed mouth part for biting and chewing. The thorax bears three pairs jointed legs and a pair of wings while the abdomen bears the respiratory, reproductive and excretive organ.
Life history
Cockroach undergoes incomplete metamorphosis, i.e. the egg stage, nymph stage and adult stage. The eggs are enclosed in a capsule called Ootheca. They are deposited in warm hidden places or carried about at the end of the abdomen of the female cockroach. Each Ootheca contain between 10 to 16 eggs. The eggs hatch within one to three months into small wingless and colourless nymphs with time. The nymphs will become brown like the adult cockroaches. They undergo several moulting, i.e. changing their skin up to five times, at the last stage of the moulting the wings appear. Each stage of the moulting is called INSTAR. As time goes on, wings will appear. On the whole, cockroach takes between 10 to 20 months to develop from egg to adult. The life span of a cockroach is about 2 ½ years.
Mode of life
As mentioned earlier, cockroach lives in dark, humid and other places such as crevices of planks, table, drawers and wardrobes and in such other places close to the source of food. Cockroaches are nocturnal in nature, i.e. they hide during the day and move about in the night. They feed on any kind of foods, books, clothing and therefore they are omnivorous. The structure of their mouth part enables them to tear up and chew different kinds of hard material.
Medical importance
Cockroaches are not known to cause any particular disease like the mosquitoes, but they carry germs and transmit same to man. Diseases such as plaque, typhoid fever, dysentery, etc. are spread by cockroaches. They are very destructive; they destroy food, clothes, books, shoes, cardboard papers and many other valuable goods. As it moves from place to place, it distributes dirt, faeces on the ground which aid in the spread of diseases.
Control measures
Cockroaches can be controlled by physical means since they live in groups, many of then can be killed at a time by using either broom or swat. Since cockroaches live and hide in dark places, residential places should be properly and adequately ventilated. Regular and proper clearing should be carried out in the drawers, cupboards in dark places both in offices and homes to remove all eggs packets, sources of food item where they cannot have access to them.
Direct or unserviceable articles such as damaged furniture, refrigerators, and abandoned automobile engines must not be kept near the wall of dwelling houses. Pit latrines and soakaway pits should be as far away from the dwelling as possible; so as to make it less likely that cockroaches which have been feeding on faeces will come into the house and attach human food.
Chemicals are used to control cockroaches. Among the insecticides that are commonly used are Sheltox, Baygon, etc. These insecticides are sprayed to kill the adult cockroaches.
