Pest control includes attempts to manage the population or location of a nuisance species. The species is considered a pest due to its impacts on the economy (including agriculture), human or animal health, or the local ecosystem. Pests may include a nuisance plant, such as a weed threatening to take over an agricultural field. But most often, the term pests refers to insects and animals. For nuisance animals, human behavioral changes can often act as a form of pest control. Other types of pest control include biological means, elimination of breeding grounds, physical destruction by fire, hunting/trapping, and chemical repellants and poisons. Of these methods, the development and use of DDT has had the greatest impact on human health. However, in recent years, less persistent ...