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  • A pesticide may be defined as any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest.

  • Pesticide exposures include (1) accidental and/or suicidal poisonings; (2) occupational exposure (manufacturing, mixing/loading, application, harvesting, and handling of crops); (3) bystander exposure to off-target drift from spraying operations; and (4) the general public who consume food items containing pesticide residues.

  • Chemical insecticides in use today poison the nervous systems of the target organisms.

  • An herbicide is any compound that is capable of either killing or severely injuring plants.

  • A fungicide is any chemical capable of preventing growth and reproduction of fungi.

Pesticides can be defined as any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating pests. Pests can be insects, rodents, weeds, and a host of other unwanted organisms. The most common classification of pesticides relies on the target species such as insecticides (insects), herbicides (weeds), fungicides (fungi, molds), rodenticides (rodents), acaricides (mites), molluscicides (snails, other mollusks), miticides (mites), larvicides (larvae), and pediculicides (lice). For regulatory purposes, plant growth regulators, repellents, and attractants (pheromones) often fall in this broad classification of chemicals.


The use of pesticides must consider the balance of the benefits that may be expected versus the possible risks of injury to human health or degradation of environmental quality. Pesticides play a major role in the control of vector-borne diseases, which represent a major threat to the health of large human populations. When introduced in 1942, DDT appeared to hold immense promise. However, because of its bioaccumulation in the environment and its effects on bird reproduction, DDT was eventually banned in most countries by the mid-1970s. In South Africa, DDT was banned in 1996 and less than 10,000 cases of malaria were registered in that country. By 2000, cases of malaria had increased to 62,000, but with the reintroduction of DDT at the end of that year, cases were down to 12,500 thus indicating its utility in controlling disease.

Use of Pesticides

Introduction of integrated pest management approaches and the increased popularity of organic farming have contributed, at least in the developed countries, to a decrease and/or stabilization of pesticide use. Pesticides are often used as formulations, in which the active ingredient is present together with other ingredients to allow mixing, dilution, application, and stability. These other ingredients are lumped under the term “inert” or “other” and may be emulsifiers, solvents, carriers, aerosol propellants, fragrances, and dyes. Though non-pesticidal, inert ingredients may not always be devoid of toxicity.


Exposure to pesticides can occur via the oral or dermal routes, or by inhalation. High oral doses, leading to severe poisoning and death, are achieved as a result of pesticide ingestion for suicidal intents, or of accidental ingestion, commonly due to storage ...

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