Insect Repellants Preparation and Properties
→ Those chemical substances which are used to kill and move away insects are called insect repeallants. Mostly, insect repellents mixes in air and affect respiratory system of insects.
→ Insect repellants are found in all three states : solid, liquid and gas. Some substances like neem leaves, tobacco leaves, sulphur etc. are used as natural insect repellants.
→ Many liquids insect repellants are sold by commercial names. Some of them are finit, bagon, endosuiphon, phenocol, phenyl etc. These are used in homes and fields as insect repellants. Some of the synthetic insect repellants are harmful for humans also. Now, herbal insect repellants like naphthalene balls, odonil, odomos etc. are used in homes.
Pheromones of Insect Repellants
→ A chemical substance produced and released into the environment by air animal, especially a mammal or an insect, affecting the behaviour or physiology of others of its species is called pheromone. Pheromones have a specific odour which is helpful in identification.
→ Pheromones can be of many types like sex pheromones, indicators etc. The main function of pheromone is sexual attraction. From ancient times, sex pheromones are secreted by females which attract males towards her. But in case of musk deer, musk is secreted in navel of male deer which attract female towards him. It is known as muskon. The structure of Pheromones can be given as:
→ Sex attracting pheromones are used for harmful insects control. The smell of pheromone is very intense. Its small quantity is detected by animals. If small amount of sex pheromone is kept at a place then opposite sex is attracted and come to that place and can be killed or sterilised. Thus, their reproduction rate is reduced and pests can be controlled. As it is not harmful for other species and is not sprayed, it does not cause any pollution.