The Main Pesticide Types
- Organophosphate Pesticides
These pesticides affect the nervous system by disrupting the enzyme that regulates acetylcholine, a neurotransmitter. Most organophosphates are insecticides. Some are very poisonous (they were used in World War II as nerve agents). However, they usually are not persistent in the environment. Examples include malathion, chlorpyrifos and phosmet.
These pesticides affect the nervous system by disrupting an enzyme that regulates acetylcholine, a neurotransmitter. The enzyme effects are usually reversible. Examples include carbonfuran and oxamyl.
- Organochlorine Insecticides
Most of this group of pesticides have been removed from the market due to their health, environmental effects and their persistence in the environment (e.g. DDT and chlordane). However many tropical countries still use DDT to control malaria. Some other examples are aldrin and dieldrin.
These were developed as a synthetic version of the naturally occurring pesticide pyrethrin, which is found in chrysanthemums. Examples include cypermethrin and deltamethrin.
The triazine herbicides work by inhibiting electron transport of photosynthesis. Certain crop plants are resistant to triazines, for example maize roots contain an enzyme that renders them inactive. This makes them useful as selective weedkillers. However, many weeds have now evolved triazine resistance. Examples include atrazine, propazine, simazine, prometone and prometryne.
Triazoles inhibit the biosynthesis of sterol, a critical component for the integrity of fungal cell membranes, resulting in abnormal fungal growth and eventually death. Because their site of action is very specific, there are resistance concerns. Applicators of triazoles are advised to rotate fungicide chemical families in their disease management programs, not simply rotate to a different member of the triazole family. Examples include epoxiconazole, cyproconazole and flusilazole.
Neonicotinoids are a class of neuro-active insecticides chemically similar to nicotine. On May 24, 2013, the European Commission imposed a number of use restrictions on neonicotinoid insecticides, which are suspected to be a contributing factor of bee colony collapse disorder. Examples include acetamiprid, clothianidin, nitenpyram, thiacloprid and imidacloprid.
- The difference between organic and inorganic pesticides:
Most pesticide active ingredients are either inorganic or organic pesticides. From a scientific view, inorganic pesticides do not contain carbon and are usually derived from mineral ores extracted from the earth. Examples of inorganic pesticides include copper sulphate, ferrous sulphate, copper and sulphur. Organic pesticides contain carbon in their chemical structure. Examples of organic pesticides include captan, pyrethrin and glyphosate.