Chapter 2 - Chemistry of Pesticides

Abstract

Since the introduction of synthetic organic pesticides, a variety of forces have influenced the types of compound and the approaches to the discovery of new pesticides. The success rate in terms of compounds that could be brought to the market diminished as the criteria imposed by long term toxicology and environmental criteria influenced the selection of new compounds. Active ingredients of pesticides represent a very diverse array of chemical structures including many biological agents. Many pesticide structures are very complex and cannot be categorized simply; therefore, classification systems in use have evolved to accommodate the increasing diversity of chemical and biological agents used in pest control or management. Pesticides are classified on the basis of target organisms, for example, herbicides, insecticides, fungicides, nematicides, and rodenticides. These classes then may be conveniently subdivided into smaller classes based on chemical structure, but a classification system based on mode of action may be equally valid. At present, many fundamental assumptions involved in the application of chemicals to pest control have been questioned, and pest management emphasizes complementary approaches. Current technology can now provide growers with more accurate information concerning the development of pest infestations and their potential economic impact. Pesticide application is now designed to minimize non-target effects by more precise application techniques, systems that react to sensors, and use only as needed.