Pesticides
Historical Perspective In the beginning, different natural substances were used as pesticides. ... During the last 50 years or so, chemical synthesis of pesticides has increased very much. Now, there are more than 55 classes and 1,500 individual substances produced in more than 10,000 formulations of pesticides. Pesticides are created to control or destroy pests. ... Pesticides are also defined by their method of distribution (such as fumigant) or mode of action (such as ovicide which kills eggs of pests). ... However, there are some problems associated with pesticides in the environment and with health. Health and comfort One of the main contributions of pesticides to the control of human diseases is in the control of diseases spread by arthropods and the other vectors. ... Other pesticides have helped as well, but the chlorinated hydrocarbon insecticides, especially DDT, are the most important in the control of insect-borne disease in humans. ... html Agriculture and forestry Pesticides have permitted maintenance of our food supply even with a continued increase of the population and decrease of area suitable for agriculture. ... Protection of Stored Products Some examples of what happens if pesticides are not used include the damage caused by various grain insects to food, damage by moths to wool and damage by termites to wood.