PESTICIDES

Fig: Spreading Pesticides by plane

               The crop production is reduced by insects and pests. For the control of insects and pests the chemicals (compounds/medicines) are used called insecticides and pesticides. To fulfil the demand of food for overgrowing population damage of crops from the insects and pests had to be controlled. The chemical used to kill the insects is called pesticides.

               Many chemical substances are used as pesticides. After world war II. Cyanide and nicotine were extensively used to control the pests. Now a days, the compounds containing chlorine and phosphorous are used as pesticides. Some compounds are listed below:

Organophoshporous compounds	Organochlorine compounds
Malathion Parathion Methyl parathion Diazinon Fenitrothion Carbofuran	DDT (Dichlorodiphenyl Trichloroethane) BHC (Benzene Hexa Chloride) Dieldrin Aldrin Lindane Chlordane

               Agricultural production has been strangely increased due to the use of insecticides and pesticides. May be, this is one of the reason that the food grains for the overgrowing population has been fulfilled.

               DDT is one of the extensively used pesticides. But due to the excessive use of the organochlorine compounds abnormalities are caused.

Fig: Effect of DDT

               Due to the use of DDT birds lay less number of eggs and the outer shell of eggs are thin. This has affected in fishery also. Human beings when exposed to an environment of DDT for long time may suffer from cancer. DDT has advantages over disadvantages and due to the reason that it is readily available and cheap, it has been used largly and mostly.

Due to the use of Dieldrin and Aldrin many wild lives have been destroyed and may be the same reasons for the stoppage of its use. The resistance in insects and pests increase when same medicine is used repeatedly and the medicine may not affect them.