ABSTRACT
Pesticides are chemicals used to remove pests such as insects and weeds. Of all the environmental contaminants, pesticides have probably been the most widely criticized due to their direct use in natural systems. The nature of pesticide usage often requires broad distribution over large areas of crops. This wide treatment of the crop environment often results in treatment of adjacent areas as well. This in itself creates concern, since people and natural organisms are exposed to these chemicals. The use of pesticides in agriculture and other areas is not recent. Prior to the 1940s, insecticides such as lime, sulfur, nicotine, pyrethrum, kerosene, and rotenone were extensively used. These pesticides suffer from a number of deficiencies. In particular, they lack potency with a wide range of insects. In addition, they lack persistence in the environment, so that repeated usage is frequently required. Finally, as a group, these substances are costly to produce and use.
