Pesticides are biocide chemicals, either synthetic chemicals, biologically-based, or naturally occurring (e.g. garlic and mint oil), used to treat a variety of pests. They may prevent, destroy, repel, or mitigate. In agriculture, targets include weeds (herbicides), fungi and fungal spores (fungicides), insects (insecticides), with various subclasses of compounds.
Individual pesticides have unique health concerns. Residue levels vary.
The Stockholm Convention on Persistent Organic Pollutants’ list of the most dangerous persistent organic chemicals includes nine pesticides. Pesticides are integral to monoculture farming, which produces high crop yield but can damage biological diversity, reduce soil quality, encourage pesticide resistance, and promote the need for GMO crops continually adapted to pesticide resistance. Pesticides may be seriously toxic chemicals and can have negative health effects on workers in farms who are exposed to much higher levels than the trace amounts in most commercial foods.