Neonicotinoids
Neonicotinoids (pronunciation: nee-oh-ni-co-ti-noids) are a class of neuro-active insecticides chemically similar to nicotine. The name itself is derived from the words "neonic," meaning new, and "nicotinoid," referring to the nicotine-like properties of these substances.
History
The development of neonicotinoids began in the 1980s and 1990s in response to the need for new, effective pesticides that were less harmful to mammals and the environment than the organophosphate and carbamate insecticides in use at the time. The first neonicotinoid, Imidacloprid, was introduced to the market by Bayer in 1991.
Mechanism of Action
Neonicotinoids act on the central nervous system of insects, causing paralysis and death. They bind to the nicotinic acetylcholine receptors (nAChRs) in the insect's brain, leading to overstimulation of the nervous system.
Types of Neonicotinoids
There are several types of neonicotinoids, including Imidacloprid, Clothianidin, Thiamethoxam, Acetamiprid, and Thiacloprid. Each has a slightly different chemical structure and mode of action, but all are used for their insecticidal properties.
Environmental Impact
Neonicotinoids are systemic pesticides, meaning they are absorbed by the plant and distributed throughout its tissues. This can lead to contamination of pollen and nectar, posing a risk to pollinators such as bees. There is ongoing debate about the extent of this risk and the role of neonicotinoids in Colony Collapse Disorder.
Health Effects
While neonicotinoids are less toxic to mammals than to insects, there is some evidence to suggest that they may have adverse effects on human health, particularly in relation to the nervous system. However, more research is needed in this area.
Regulation
The use of neonicotinoids is regulated in many countries due to concerns about their impact on pollinators and the environment. In 2018, the European Union banned the outdoor use of three neonicotinoids - clothianidin, imidacloprid, and thiamethoxam - due to their harmful effects on bees.
See Also
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