Pesticides can be categorized into the following: Organophosphates, Organochlorines, Carbamates, Pyrethroids and Green Pesticides.
Organochlorines are organic compound containing at least one covalently bonded chlorine atom. Their wide structural variety and divergent chemical properties lead to a broad range of applications.
Many pesticides contain chlorine. However, many of its derivatives are controversial and some have been banned in various countries because of the adverse effects of these compounds on the environment.
Some of the notable examples include DDT, dicofol, heptachlor, endosulfan, chlordane,aldrin, dieldrin, endrin, mirex, and pentachlorophenol.
Organophosphates – refers to a group of insecticide or nerve agents acting on the enzymeacetylcholinesterase. Organophosphate pesticides irreversibly inactivate acetylcholinesterase, which is essential to nerve function in insects, humans, and many other animals.
Organophosphate pesticides degrade rapidly by hydrolysis on exposure to sunlight, air, and soil, although small amounts can be detected in food and drinking water. Their ability to degrade made them an attractive alternative to the persistent organochloride pesticides, such as DDT,aldrin and dieldrin. Although organophosphates degrade faster than the organochlorides, they have greater acute toxicity, posing risks to people who may be exposed to large amounts
Commonly used organophosphates have included parathion, methyl parathion,chlorpyrifos, diazinon, dichlorvos, phosmet, tetrachlorvinphos, and azinphos methyl.
An example of Organophosphate termiticide available in the South Africa is Contra Insect 480 TEC which contains the active ingredient Chlorpyrifos.
Carbamates – are organic compounds derived from carbamic acid (NH2COOH). A carbamate group, carbamate ester, and carbamic acids are functional groups that are inter-related structurally and often are interconverted chemically. Carbamate esters are also called urethanes.
Carbamate insecticides kill insects by reversibly inactivating the enzymeacetylcholinesterase. The organophosphate pesticides also inhibit this enzyme, although irreversibly, and cause a more severe form of cholinergic poisoning.
Some examples of insecticides from this group are aldicarb, carbofuran, Furadan,fenoxycarb, carbaryl (Sevin), ethienocarb, and fenobucarb.
Pyrethroids – are synthetic chemical compounds similar to the natural chemical pyrethrinsproduced by the flowers of pyrethrums (Chrysanthemum cinerariaefolium and C. coccineum). Pyrethroids now constitute a major proportion of the synthetic insecticide market and are common in commercial products such as household insecticides. In the concentrations used in such products, they may also have insect repellent properties and are generally harmless to human beings in low doses but can harm sensitive individuals. They are usually broken apart bysunlight and the atmosphere in one or two days, and do not significantly affect groundwaterquality.
Some examples of pyrethroids are Allethrin, Bifenthrin, Cypermethrin, Cyfluthrin, Fenvalerate and Permethrin.
An example of a pyrethroid termiticide available in the South Africa is Premise SC 200 whichcontains the active ingredient Imidacloprid
Green pesticides – are pesticides derived from organic sources which are consideredenvironmentally friendly and causing less harm to human and animal health, and tohabitats and the ecosystem. These pesticides are also called ecological pesticides.
In agroecology, pesticides are evaluated for minimal adverse environmental effects.Biocides include germicides, antibiotics, antibacterials, antivirals, antifungals, antiprotozoals and antiparasites. Pesticides typically come in the form of sprays anddusts. Many ecological pesticides are biological pesticides, but others are minerals or chemical compounds.
An example of a green pesticide available in the South Africa is Bora-Care which contains a borate mineral salt as its active ingredient.