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Neonicotinoids (sometimes shortened to neonics ) are a class of neuro-active
insecticide Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to b ...
s chemically similar to
nicotine Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As ...
, developed by scientists at
Shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard o ...
and
Bayer Bayer AG (, commonly pronounced ; ) is a German multinational corporation, multinational pharmaceutical and biotechnology company and one of the largest pharmaceutical companies in the world. Headquartered in Leverkusen, Bayer's areas of busi ...
in the 1980s. The neonicotinoid family includes
acetamiprid Acetamiprid is an organic compound with the chemical formula C10H11ClN4. It is an odorless neonicotinoid insecticide produced under the trade names Assail, and Chipco by Aventis CropSciences. It is systemic and intended to control sucking insects ...
,
clothianidin Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides that are chemically similar to nicotine, which has be ...
,
dinotefuran Dinotefuran is an insecticide of the neonicotinoid class developed by Mitsui Chemicals for control of insect pests such as aphids, whiteflies, thrips, leafhoppers, leafminers, sawflies, mole cricket, white grubs, lacebugs, billbugs, beetles, m ...
,
imidacloprid Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system. ...
,
nitenpyram Nitenpyram is a chemical frequently used as an insecticide in agriculture and veterinary medicine. The compound is an insect neurotoxin belonging to the class of neonicotinoids which works by blocking neural signaling of the central nervous syst ...
, nithiazine,
thiacloprid Thiacloprid is an insecticide of the neonicotinoid class. Its mechanism of action is similar to other neonicotinoids and involves disruption of the insect's nervous system by stimulating nicotinic acetylcholine receptors. Thiacloprid was develop ...
and
thiamethoxam Thiamethoxam is the ISO common name for a mixture of ''cis-trans'' isomers used as a systemic insecticide of the neonicotinoid class. It has a broad spectrum of activity against many types of insects and can be used as a seed dressing. Histor ...
. Imidacloprid has been the most widely used insecticide in the world from 1999 through . Compared to
organophosphate In organic chemistry, organophosphates (also known as phosphate esters, or OPEs) are a class of organophosphorus compounds with the general structure , a central phosphate molecule with alkyl or aromatic substituents. They can be considered a ...
and
carbamate In organic chemistry, a carbamate is a category of organic compounds with the general formula and structure , which are formally derived from carbamic acid (). The term includes organic compounds (e.g., the ester ethyl carbamate), formally o ...
insecticides, neonicotinoids are less toxic to birds and mammals. Neonicotinoid use has been studied in relation to adverse ecological effects, including
honey-bee A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current co ...
colony collapse disorder Colony collapse disorder (CCD) is an abnormal phenomenon that occurs when the majority of worker bees in a honey bee colony disappear, leaving behind a queen, plenty of food, and a few nurse bees to care for the remaining immature bees. While s ...
(CCD), and declining populations of insect-eating birds. In 2013, the
European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
and some neighbouring countries restricted the use of certain neonicotinoids. In 2018 the EU banned the three main neonicotinoids (
clothianidin Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides that are chemically similar to nicotine, which has be ...
,
imidacloprid Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system. ...
and
thiamethoxam Thiamethoxam is the ISO common name for a mixture of ''cis-trans'' isomers used as a systemic insecticide of the neonicotinoid class. It has a broad spectrum of activity against many types of insects and can be used as a seed dressing. Histor ...
) for all outdoor uses, but in 2020, France re-allowed the use of neonicotinoids on
sugar beet A sugar beet is a plant whose root contains a high concentration of sucrose and which is grown commercially for sugar production. In plant breeding, it is known as the Altissima cultivar group of the common beet (''Beta vulgaris''). Together wi ...
crops. Several US states have restricted neonicotinoids out of concern for pollinators and bees.


History

The
precursor Precursor or Precursors may refer to: *Precursor (religion), a forerunner, predecessor ** The Precursor, John the Baptist Science and technology * Precursor (bird), a hypothesized genus of fossil birds that was composed of fossilized parts of unr ...
to nithiazine was first synthesized by Henry Feuer, a chemist at Purdue University, in 1970.
Shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard o ...
researchers found in screening that this precursor showed insecticide potential and refined it to develop nithiazine. In 1984 nithiazine's mode of action was found to be as a postsynaptic acetylcholine receptor agonist, the same as
nicotine Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As ...
. Nithiazine does not act as an
acetylcholinesterase inhibitor Acetylcholinesterase inhibitors (AChEIs) also often called cholinesterase inhibitors, inhibit the enzyme acetylcholinesterase from breaking down the neurotransmitter acetylcholine into choline and acetate, thereby increasing both the level and ...
, in contrast to the
organophosphate In organic chemistry, organophosphates (also known as phosphate esters, or OPEs) are a class of organophosphorus compounds with the general structure , a central phosphate molecule with alkyl or aromatic substituents. They can be considered a ...
and
carbamate In organic chemistry, a carbamate is a category of organic compounds with the general formula and structure , which are formally derived from carbamic acid (). The term includes organic compounds (e.g., the ester ethyl carbamate), formally o ...
insecticides. While nithiazine has the desired specificity (i.e. low mammalian toxicity), it is not photostable—that is, it breaks down in sunlight, and thus is not commercially viable. In 1985, Bayer (Shinzo Kagabu) patented
imidacloprid Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system. ...
as the first commercial neonicotinoid. During the late 1990s, imidacloprid became widely used. Beginning in the early 2000s, two other neonicotinoids,
clothianidin Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides that are chemically similar to nicotine, which has be ...
and
thiamethoxam Thiamethoxam is the ISO common name for a mixture of ''cis-trans'' isomers used as a systemic insecticide of the neonicotinoid class. It has a broad spectrum of activity against many types of insects and can be used as a seed dressing. Histor ...
, entered the market. , virtually all US corn was treated with one of these two insecticides. , about a third of US
soybean The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu an ...
acreage was planted with neonicotinoid-treated seeds, usually imidacloprid or thiamethoxam.


Market

Neonicotinoids have been registered in more than 120 countries. With a global turnover of €1.5 billion in 2008, they represented 24% of the global insecticide market. The market grew from €155 million in 1990 to €957 million in 2008. Neonicotinoids made up 80% of all seed treatment sales in 2008. As of 2011, seven neonicotinoids from different companies were on the market.


Agricultural usage


Efficacy

Imidacloprid is effective against sucking insects, some chewing insects, soil insects and fleas on domestic animals. It is
systemic Systemic fundamental to a predominant social, economic, or political practice. This refers to: In medicine In medicine, ''systemic'' means affecting the whole body, or at least multiple organ systems. It is in contrast with ''topical'' or ''loc ...
with particular efficacy against sucking insects and has a long residual activity. Imidacloprid can be added to the water used to irrigate plants. Controlled release formulations of imidacloprid take 2–10 days to release 50% of imidacloprid in water. It is applied against soil pests, seed, timber and animal pests as well as foliar treatments. neonicotinoids were used in the U.S. on about 95 percent of corn and canola crops, the majority of cotton, sorghum, and sugar beets and about half of all soybeans. They have been used on the vast majority of fruit and vegetables, including apples, cherries, peaches, oranges, berries, leafy greens, tomatoes, and potatoes, to cereal grains, rice, nuts, and wine grapes. Imidacloprid was possibly the most widely used insecticide, both within the neonicotinoids and in the worldwide market.


Seed coatings

In agriculture, usefulness of neonicotinoid seed treatments for pest prevention depends upon the timing of planting and pest arrival. For soybeans, neonicotinoid seed treatments typically are not effective against the
soybean aphid The soybean aphid (''Aphis glycines'') is an insect pest of soybean (''Glycine max'') that is exotic to North America. The soybean aphid is native to Asia. It has been described as a common pest of soybeans in China and as an occasional pest of ...
, because the compounds break down 35–42 days after planting, and soybean aphids typically are not present or at damaging population levels before this time. Neonicotinoid seed treatments can protect yield in individual cases such as late-planted fields or in areas with large infestations much earlier in the growing season. Overall yield gains are not expected from neonicotinoid seed treatments for soybean insect pests in the United States, and foliar insecticides are recommended instead when insects do reach damaging levels. Health Canada estimated that neonicotinoids provide benefits equivalent to over 3% of the national farm gate value of corn and 1.5% to 2.1% of the national farm gate value of soybean in 2013 .


Regulation


United States

The
US EPA The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...
operates a 15-year registration review cycle for all pesticides. The EPA granted a conditional registration to clothianidin in 2003. The EPA issues conditional registrations when a pesticide meets the standard for registration, but there are outstanding data requirements. Thiamethoxam is approved for use as an
antimicrobial An antimicrobial is an agent that kills microorganisms or stops their growth. Antimicrobial medicines can be grouped according to the microorganisms they act primarily against. For example, antibiotics are used against bacteria, and antifungals ar ...
pesticide wood preservative and as a pesticide; it was first approved in 1999. Imidacloprid was registered in 1994. As all neonicotinoids were registered after 1984, they were not subject to reregistration, but because of environmental concerns, especially concerning bees, the EPA opened dockets to evaluate them. The registration review docket for
imidacloprid Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system. ...
opened in December 2008, and the docket for nithiazine opened in March 2009. To best take advantage of new research as it becomes available, the EPA moved ahead the docket openings for the remaining neonicotinoids on the registration review schedule (
acetamiprid Acetamiprid is an organic compound with the chemical formula C10H11ClN4. It is an odorless neonicotinoid insecticide produced under the trade names Assail, and Chipco by Aventis CropSciences. It is systemic and intended to control sucking insects ...
,
clothianidin Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides that are chemically similar to nicotine, which has be ...
,
dinotefuran Dinotefuran is an insecticide of the neonicotinoid class developed by Mitsui Chemicals for control of insect pests such as aphids, whiteflies, thrips, leafhoppers, leafminers, sawflies, mole cricket, white grubs, lacebugs, billbugs, beetles, m ...
,
thiacloprid Thiacloprid is an insecticide of the neonicotinoid class. Its mechanism of action is similar to other neonicotinoids and involves disruption of the insect's nervous system by stimulating nicotinic acetylcholine receptors. Thiacloprid was develop ...
, and
thiamethoxam Thiamethoxam is the ISO common name for a mixture of ''cis-trans'' isomers used as a systemic insecticide of the neonicotinoid class. It has a broad spectrum of activity against many types of insects and can be used as a seed dressing. Histor ...
) to FY 2012. The EPA said that it expected to complete the review for the neonicotinoids in 2018. In March 2012, the
Center for Food Safety The Center for Food Safety (CFS) is a 501c3, U.S. non-profit advocacy organization, based in Washington, D.C. It maintains an office in San Francisco, California. The executive director is Andrew Kimbrell, an attorney. Its stated mission is to ...
,
Pesticide Action Network Pesticide Action Network (PAN) is "an international coalition of around 600 NGO A non-governmental organization (NGO) or non-governmental organisation (see spelling differences) is an organization that generally is formed independent from go ...
, Beyond Pesticides and a group of beekeepers filed an Emergency Petition with the EPA asking the agency to suspend the use of clothianidin. The agency denied the petition. In March 2013, the
US EPA The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...
was sued by the same group, with the
Sierra Club The Sierra Club is an environmental organization with chapters in all 50 United States, Washington D.C., and Puerto Rico. The club was founded on May 28, 1892, in San Francisco, California, by Scottish-American preservationist John Muir, who be ...
and the
Center for Environmental Health The Center for Environmental Health (CEH) is an American non-profit organization (501(c)(3)) organization working to protect children and families from harmful chemicals in air, food, water and in everyday products. Its vision and mission are "(A) w ...
joining, which accused the agency of performing inadequate toxicity evaluations and allowing insecticide registration based on inadequate studies. The case, ''Ellis et al v. Bradbury et al'', was stayed as of October 2013. On 12 July 2013, Rep.
John Conyers John James Conyers Jr. (May 16, 1929October 27, 2019) was an American politician of the Democratic Party who served as a U.S. representative from Michigan from 1965 to 2017. The districts he represented always included part of western Detroit. ...
, on behalf of himself and Rep.
Earl Blumenauer Earl Francis Blumenauer ( ; born August 16, 1948) is an American lawyer, author, and politician serving as the U.S. representative for since 1996. The district includes most of Portland east of the Willamette River. A member of the Democratic P ...
, introduced the "Save American Pollinators Act" in the House of Representatives. The Act called for suspension of the use of four neonicotinoids, including the three recently suspended by the European Union, until their review is complete, and for a joint
Interior Department An interior ministry (sometimes called a ministry of internal affairs or ministry of home affairs) is a government department that is responsible for internal affairs. Lists of current ministries of internal affairs Named "ministry" * Ministry ...
and EPA study of bee populations and the possible reasons for their decline. The bill was assigned to a congressional committee on 16 July 2013 and did not leave committee. The US EPA has taken a variety of actions to regulate neonicotinoids in response to concerns about pollinators. In 2014, under the
Obama administration Barack Obama's tenure as the 44th president of the United States began with his first inauguration on January 20, 2009, and ended on January 20, 2017. A Democrat from Illinois, Obama took office following a decisive victory over Republican ...
, a blanket ban was issued against the use of neonicotinoids on
National Wildlife Refuges National Wildlife Refuge System is a designation for certain protected areas of the United States managed by the United States Fish and Wildlife Service. The National Wildlife Refuge System is the system of public lands and waters set aside to c ...
in response to concerns about off-target effects of the pesticide, and a lawsuit from environmental groups. In 2018, the
Trump administration Donald Trump's tenure as the List of presidents of the United States, 45th president of the United States began with Inauguration of Donald Trump, his inauguration on January 20, 2017, and ended on January 20, 2021. Trump, a Republican Party ...
reversed this decision, stating that decisions on neonicotinoid usage on farms in wildlife refuges will be made on a case by case basis. In May 2019, the Environmental Protection Agency revoked approval for a dozen pesticides containing clothianidin and thiamethoxam as part of a legal settlement.


European Union

The first neonic was approved in the EU in 2005. In 2008, Germany revoked the registration of
clothianidin Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides that are chemically similar to nicotine, which has be ...
for use on seed corn after an incident that resulted in the death of millions of nearby honey bees. An investigation revealed that it was caused by a combination of factors: * failure to use a polymer seed coating known as a "sticker"; * weather conditions that resulted in late planting when nearby
canola Close-up of canola blooms Canola flower Rapeseed oil is one of the oldest known vegetable oils. There are both edible and industrial forms produced from rapeseed, the seed of several cultivars of the plant family Brassicaceae. Historically, i ...
crops were in bloom; * a particular type of air-driven equipment used to sow the seeds which apparently blew clothianidin-laden dust off the seeds and into the air as the seeds were ejected from the machine into the ground; * dry and windy conditions at the time of planting that blew the dust into the nearby canola fields where honey bees were foraging. In Germany, clothianidin use was also restricted in 2008 for a short period on
rapeseed Rapeseed (''Brassica napus ''subsp.'' napus''), also known as rape, or oilseed rape, is a bright-yellow flowering member of the family Brassicaceae (mustard or cabbage family), cultivated mainly for its oil-rich seed, which naturally contains a ...
. After it was shown that rapeseed treatment did not have the same problems as
maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. Th ...
, its use was reinstated under the condition that the pesticide be fixed to the rapeseed grains by an additional sticker, so that abrasion dusts would not be released into the air. In 2009, the German Federal Office of Consumer Protection and Food Safety decided to continue to suspend authorization for clothianidin use on corn. It had not yet been fully clarified to what extent and in what manner bees come into contact with the active substances in clothianidin,
thiamethoxam Thiamethoxam is the ISO common name for a mixture of ''cis-trans'' isomers used as a systemic insecticide of the neonicotinoid class. It has a broad spectrum of activity against many types of insects and can be used as a seed dressing. Histor ...
and
imidacloprid Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system. ...
when used on corn. The question of whether liquid emitted by plants via guttation, which bees ingest, posed an additional risk was unanswered. Neonicotinoid seed treatment is banned in
Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...
, but foliar use is allowed. This action was taken based on preliminary monitoring studies showing that bee losses were correlated with the application of seeds treated with these compounds; Italy based its decision on the known acute toxicity of these compounds to pollinators. In
France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, sunflower and corn seed treatment with imidacloprid are suspended; imidacloprid seed treatment for
sugar beet A sugar beet is a plant whose root contains a high concentration of sucrose and which is grown commercially for sugar production. In plant breeding, it is known as the Altissima cultivar group of the common beet (''Beta vulgaris''). Together wi ...
s and cereals are allowed, as is foliar use.


EU restrictions on use

In 2012, the
European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body o ...
asked the
European Food Safety Authority The European Food Safety Authority (EFSA) is the agency of the European Union (EU) that provides independent scientific advice and communicates on existing and emerging risks associated with the food chain. EFSA was established in February 2002, ...
(EFSA) to study the safety of three neonicotinoids, in response to growing concerns about the impact of neonicotinoids on honey bees. The study was published in January 2013, stating that neonicotinoids pose an unacceptably high risk to bees, and that the industry-sponsored science upon which regulatory agencies' claims of safety have relied may be flawed and contain data gaps not previously considered. Their review concluded, "A high acute risk to honey bees was identified from exposure via dust drift for the seed treatment uses in maize, oilseed rape and cereals. A high acute risk was also identified from exposure via residues in nectar and/or pollen." EFSA reached the following conclusions:EFSA identifies risks to bees from neonicotinoids
''efsa.europa.eu'' 16 January 2013.
* Exposure from pollen and nectar. Only uses on crops not attractive to honey bees were considered acceptable. * Exposure from dust. A risk to honey bees was indicated or could not be excluded, with some exceptions, such as use on sugar beet and crops planted in glasshouses, and for the use of some granules. * Exposure from
guttation Guttation is the exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses, and a number of fungi, which are not plants but were previously categorized as such and studied as part of botany. Guttation ( ...
. The only completed assessment was for maize treated with thiamethoxam. In this case, field studies showed an acute effect on honey bees exposed to the substance through guttation fluid. EFSA's scientists identified a number of data gaps and were unable to finalize risk assessments for some uses authorized in the EU. EFSA also highlighted that risk to other pollinators should be further considered. The UK Parliament asked manufacturer
Bayer Cropscience Bayer AG (, commonly pronounced ; ) is a German multinational pharmaceutical and biotechnology company and one of the largest pharmaceutical companies in the world. Headquartered in Leverkusen, Bayer's areas of business include pharmaceutica ...
to explain discrepancies in the evidence they submitted. In response to the study, the European Commission recommended a restriction of their use across the European Union. On 29 April 2013, 15 of the 27 EU member states voted to restrict the use of three neonicotinoids for two years starting 1 December 2013. Eight states voted against the ban, while four abstained. The law restricted the use of imidacloprid, clothianidin and thiamethoxam for seed treatment, soil application (granules) and
foliar A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...
treatment in crops attractive to bees. Temporary suspensions had previously been enacted in France, Germany, and Italy. In
Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...
, where neonicotinoids were never used in alpine areas, neonics were banned because of accidental poisonings of bee populations and the relatively low safety margin for other beneficial insects. Environmentalists called the move "a significant victory for common sense and our beleaguered bee populations" and said it is "crystal clear that there is overwhelming scientific, political and public support for a ban." The UK, which voted against the bill, disagreed: "Having a healthy bee population is a top priority for us, but we did not support the proposal for a ban because our scientific evidence doesn't support it." Bayer Cropscience, which makes two of the three banned products, remarked "Bayer remains convinced neonicotinoids are safe for bees, when used responsibly and properly … clear scientific evidence has taken a back-seat in the decision-making process." Reaction in the scientific community was mixed. Biochemist Lin Field said the decision was based on "political lobbying" and could lead to the overlooking of other factors involved in colony collapse disorder. Zoologist Lynn Dicks of
Cambridge University , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...
disagreed, saying "This is a victory for the
precautionary principle The precautionary principle (or precautionary approach) is a broad epistemological, philosophical and legal approach to innovations with potential for causing harm when extensive scientific knowledge on the matter is lacking. It emphasizes caut ...
, which is supposed to underlie
environmental regulation Environmental law is a collective term encompassing aspects of the law that provide protection to the environment. A related but distinct set of regulatory regimes, now strongly influenced by environmental Legal doctrine, legal principles, focu ...
." Simon Potts, Professor of Biodiversity and Ecosystem Services at
Reading University The University of Reading is a public university in Reading, Berkshire, England. It was founded in 1892 as University College, Reading, a University of Oxford extension college. The institution received the power to grant its own degrees in 192 ...
, called the ban "excellent news for pollinators", and said, "The weight of evidence from researchers clearly points to the need to have a phased ban of neonicotinoids." The decision came up for review in 2016. In March 2017, ''
The Guardian ''The Guardian'' is a British daily newspaper. It was founded in 1821 as ''The Manchester Guardian'', and changed its name in 1959. Along with its sister papers ''The Observer'' and ''The Guardian Weekly'', ''The Guardian'' is part of the Gu ...
'' printed an article which claimed that they had obtained information that indicated that the European commission wanted a complete ban and cited "high acute risks to bees". A vote on the ban was expected in 2017 but delayed until early 2018 to assess the scientific findings. On 27 April 2018, member states of the European Union agreed upon a total ban on neonicotinoid insecticide use, except within closed greenhouses, to be imposed from the end of 2018. The ban applies to the three main neonicotinoid active compounds:
clothianidin Clothianidin is an insecticide developed by Takeda Chemical Industries and Bayer AG. Similar to thiamethoxam and imidacloprid, it is a neonicotinoid. Neonicotinoids are a class of insecticides that are chemically similar to nicotine, which has be ...
,
imidacloprid Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system. ...
and
thiamethoxam Thiamethoxam is the ISO common name for a mixture of ''cis-trans'' isomers used as a systemic insecticide of the neonicotinoid class. It has a broad spectrum of activity against many types of insects and can be used as a seed dressing. Histor ...
. Use of the three compounds had been partially restricted in 2013. The vote on the proposed ban followed a February 2018 report from the
European Food Safety Authority The European Food Safety Authority (EFSA) is the agency of the European Union (EU) that provides independent scientific advice and communicates on existing and emerging risks associated with the food chain. EFSA was established in February 2002, ...
which concluded that neonicotinoids posed a high risk to both domestic and wild bees. Voting on the issue had previously been postponed on multiple occasions. The ban had strong public support, but faced criticism from the agrochemical industry, and from certain farmers' groups.


Economic impact

In January 2013, the Humboldt Forum for Food and Agriculture e. V. (HFFA), a non-profit
think tank A think tank, or policy institute, is a research institute that performs research and advocacy concerning topics such as social policy, political strategy, economics, military, technology, and culture. Most think tanks are non-governmenta ...
, published a report on the value of neonicotinoids in the EU. At their website HFFA lists as their partners/supporters: BASF SE, the world's largest chemical company;
Bayer CropScience Bayer AG (, commonly pronounced ; ) is a German multinational pharmaceutical and biotechnology company and one of the largest pharmaceutical companies in the world. Headquartered in Leverkusen, Bayer's areas of business include pharmaceutica ...
, makers of products for crop protection and nonagricultural pest control; E.ON, an electric utility service provider; KWS Seed, a seed producer; and the food company
Nestlé Nestlé S.A. (; ; ) is a Switzerland, Swiss multinational food and drink processing conglomerate corporation headquartered in Vevey, Vaud, Switzerland. It is the largest publicly held food company in the world, measured by revenue and other me ...
. The study was supported by
COPA-COGECA COPA-COGECA ( / Committee of Professional Agricultural Organisations-General Confederation of Agricultural Cooperatives), is the union of the two big agricultural umbrella organisations COPA and COGECA and the strongest interest group for Europea ...
, the European Seed Association and the European Crop Protection Association, and financed by neonicotinoid manufacturers Bayer CropScience and
Syngenta Syngenta AG is a provider of agricultural science and technology, in particular seeds and pesticides with its management headquarters in Basel, Switzerland. It is owned by ChemChina, a Chinese state-owned enterprise. Syngenta was founded in 2 ...
. The report looked at the short- and medium-term impacts of a complete ban of all neonicotinoids on agricultural and total
value added In business, total value added is calculated by tabulating the unit value added (measured by summing unit profit sale price and production cost">Price.html" ;"title="he difference between Price">sale price and production cost], unit depreciatio ...
(VA) and employment, global prices, land use and greenhouse gas emissions, greenhouse gas (GHG) emissions. In the first year, agricultural and total VA would decline by €2.8 and €3.8 billion, respectively. The greatest losses would be in wheat, maize and rapeseed in the UK, Germany, Romania and France. 22,000 jobs would be lost, primarily in Romania and Poland, and agricultural incomes would decrease by 4.7%. In the medium-term (5-year ban), losses would amount to €17 billion in VA, and 27,000 jobs. The greatest income losses would affect the UK, while most jobs losses would occur in Romania. Following a ban, the lowered production would induce more imports of agricultural commodities into the EU. Agricultural production outside the EU would expand by 3.3 million hectares, leading to additional emissions of 600 million tons of
carbon dioxide equivalent Global warming potential (GWP) is the heat absorbed by any greenhouse gas in the atmosphere, as a multiple of the heat that would be absorbed by the same mass of carbon dioxide (). GWP is 1 for . For other gases it depends on the gas and the time ...
. When the report was released, Peter Melchett, policy director of the
Soil Association The Soil Association is a British registered charity. The organisation activities include campaigning – against intensive farming, for local purchasing and public education on nutrition – and certification of organic foods. It was establis ...
, which has been working to ban neonicotinoids in the UK, commented that since the report was funded by Bayer Crop Sciences and Syngenta, "it was probably unlikely to conclude that neonicotinoids should be banned". The spokesperson further stated: "On the one hand, the chemical companies say we risk the additional costs to farmers amounting to £630 million. On the other, the possible cost of losing pollinating insects is thought to be worth three times as much (£1.8 billion*) to UK farmers."


Canada

Use of pesticides in Canada is a matter of
federal jurisdiction Federal jurisdiction is the jurisdiction of the federal government in any country that uses federalism. Such a country is known as a Federation. Federal jurisdiction by country All federations, by definition, must have some form of federal juri ...
. In 2016, Health Canada proposed phasing out imidacloprid over the next three to five years. The government has voiced concerns regarding the impact of neonics on bees, invertebrate waterspecies, and birds. In
Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
, nearly all corn seeds and a majority of soybeans get treated with neonicotinoids. In the summer of 2015, the province passed a law to reduce the presence of neonicotinoids. Ontario's regulations were written to reduce the percent of seeds and beans covered with neonicotinoids to 20 percent within two years. On 10 December 2015, Montreal banned all neonicotinoids – without exception – on all properties within the city limits, including the Botanical Garden, all agricultural areas and all golf courses. Agricultural businesses opposed Montreal's ban. In July 2016, British Columbia's largest city, Vancouver, banned the use of neonics within Vancouver city limits, where it was primarily being used to kill off chafer beetles living under home lawns.


Oceania

On 11 October 2019, the Fiji government announced a ban on imidacloprid, effective 1 January 2020.


Chemical activity and properties

Neonicotinoids, like nicotine, bind to
nicotinic acetylcholine receptor Nicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral ne ...
s (nAChRs) of a cell and trigger a response by that cell. In mammals, nicotinic acetylcholine receptors are located in cells of both the
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
and
peripheral nervous system The peripheral nervous system (PNS) is one of two components that make up the nervous system of bilateral animals, with the other part being the central nervous system (CNS). The PNS consists of nerves and ganglia, which lie outside the brain ...
s. In insects these receptors are limited to the central nervous system. Nicotinic acetylcholine receptors are activated by the
neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, any main body part or target cell, may be another neuron, but could also be a gland or muscle cell. Neuro ...
acetylcholine Acetylcholine (ACh) is an organic chemical that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Part ...
. While low to moderate activation of these receptors causes nervous stimulation, high levels overstimulate and block the receptors, causing
paralysis Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 50 ...
and death.
Acetylcholinesterase Acetylcholinesterase (HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme Enzymes () are proteins that a ...
breaks down acetylcholine to terminate signals from these receptors. However, acetylcholinesterase cannot break down neonicotinoids and their binding is irreversible.


Basis of selectivity

Mammals and insects have different composition of the receptor subunits and the
structures A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...
of the receptors. Because most neonicotinoids bind much more strongly to insect
neuron A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. N ...
receptors than to mammal neuron receptors, these insecticides are more toxic to insects than mammals. The low mammalian toxicity of imidacloprid has been explained by its inability to cross the
blood–brain barrier The blood–brain barrier (BBB) is a highly selective semipermeable membrane, semipermeable border of endothelium, endothelial cells that prevents solutes in the circulating blood from ''non-selectively'' crossing into the extracellular fluid of ...
because of the presence of a charged nitrogen atom at physiological pH. The uncharged molecule can penetrate the insect blood–brain barrier. Other neonicotinoids have a negatively charged nitro or cyano group, which interacts with a unique, positively charged
amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
residue present on insect, but not mammalian nAChRs. However, the breakdown product desnitro-imidacloprid, which is formed in a mammal's body during
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
as well as in environmental breakdown of imidacloprid, has a charged nitrogen and shows high affinity to mammalian nAChRs. Desnitro-imidacloprid is quite toxic to mice. Toxic action may result from the active ingredient itself or from its
residue Residue may refer to: Chemistry and biology * An amino acid, within a peptide chain * Crop residue, materials left after agricultural processes * Pesticide residue, refers to the pesticides that may remain on or in food after they are applied ...
. is a common degradation product of multiple neonicotinoids.


Persistence and half-life

Most neonicotinoids are water-soluble and break down slowly in the environment, so they can be taken up by the plant and provide protection from insects as the plant grows. Independent studies show that the
photodegradation Photodegradation is the alteration of materials by light. Commonly, the term is used loosely to refer to the combined action of sunlight and air, which cause oxidation and hydrolysis. Often photodegradation is intentionally avoided, since it destroy ...
half-life time of most neonicotinoids is around 34 days when exposed to sunlight. However, it might take up to 1,386 days (3.8 years) for these compounds to degrade in the absence of sunlight and micro-organism activity. Some researchers are concerned that neonicotinoids applied agriculturally might accumulate in
aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...
s.


Environmental and species impact


Bees

A dramatic rise in the number of annual beehive losses noticed around 2006 spurred interest in factors potentially affecting bee health. Many biological factors influence colony collapse disorder, including varroa mite infestation and Israeli acute paralysis virus (IAPV). Despite much speculation on the role of neonicotinoids, many collapsing colonies show no trace of them. Research has suggested potential toxicity to honey bees and other beneficial insects even with low levels of exposure. In lab studies, neonicotinoids were shown to increase mortality rates and may induce multiple sublethal effects in exposed bees, including the ability to fly and forage. Neonicotinoids may also be responsible for detrimental effects on the
bumblebee A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only extant group in the tribe Bombini, though a few extinct related gener ...
, another important pollinator. In general, however, despite the fact that many laboratory studies have shown the potential for neonicotinoid toxicity, the majority of field studies have found only limited or no effects on honey bees. In April 2015
EASAC The European Academies' Science Advisory Council (EASAC) is a regional association of National Academies of science. Its members are 25 National Science Academies of the Member States of the European Union (EU), and the National Science Academies o ...
conducted a study of the potential effects on organisms providing a range of ecosystem services like pollination and natural pest control which are critical to
sustainable agriculture Sustainable agriculture is farming in sustainable ways meeting society's present food and textile needs, without compromising the ability for current or future generations to meet their needs. It can be based on an understanding of ecosystem ser ...
. The resulting report concludes "there is an increasing body of evidence that the widespread prophylactic use of neonicotinoids has severe negative effects on non-target organisms that provide ecosystem services including pollination and natural pest control." A 2015 systematic review (Lundin et al., 2015) of the scientific literature on neonicotinoids and bees concluded that despite considerable research efforts, there are still significant knowledge gaps concerning the impacts of neonicotinoids on bees. A review article (Carreck & Ratnieks, 2015) concluded that while laboratory based studies have demonstrated adverse sub-lethal effects of neonicotinoid insecticides on honey bees and bumble bees, these same effects have not been observed in field studies, which is likely due to an overestimation of three key dosage factors (concentration, duration and choice) in many laboratory based studies. In 2017, researchers demonstrated the combined effects of nutritional stress and low doses of common, widely used neonicotinoid pesticides (clothianidin, thiamethoxam) found in nectar and pollen. Their results provided the first demonstration that neonicotinoids and nutrition levels can synergistically interact and cause significant harm to animal survival, showing the complexity of neonicotinoid effects. In addition, the combined exposure reduced bee food consumption and hemolymph (bee blood) sugar levels. Declines in managed and wild bee populations have been attributed, in part, to the combination of direct and indirect effects of neonicotinoids that render them vulnerable to pathogens. A 2017 survey covering every continent with honeybees found neonicotinoids in three-fourths of honey samples, albeit in every case at levels considered safe for human consumption.


Birds

Neonicotinoids may have adverse effects on bird population. Neonicotinoid dust intended for plants and seed coatings can spread throughout the air and seep into the water, which unintentionally affects non-target wildlife. Globally, 60% of neonicotinoids are used as seed coatings. Some seed-eating bird species can be poisoned by neonicotinoid-coated seeds. There have been reports of developmental abnormalities and reduced eggshell thickness, fertilization success, and embryo size with direct exposure to pesticides including neonicotinoids. Some studies suggest burying neonicotinoid seeds used for agriculture below the surface of the soil will prevent birds from eating them. Neonicotinoids can have non-direct impacts on birds by disrupting the food chain. The main goal of neonicotinoids is to target pests. However, this negatively affects insectivorous bird populations that rely on these insects for food. Neonicotinoids can also leach into soil, accumulating in bodies of water that normally incubate insects. A 2014 observational study conducted in the Netherlands correlated declines in some bird populations with environmental imidacloprid residues, although it stopped short of concluding that the association was casual.


Other wildlife

In March 2013, the
American Bird Conservancy American Bird Conservancy (ABC) is a non-profit membership organization with the mission of conserving wild birds and their habitats throughout the Americas. Its focus is on threats to birds in the Western Hemisphere – threats which include ov ...
published a commentary on 200 studies on neonicotinoids calling for a ban on neonicotinoid use as seed treatments because of their toxicity to birds, aquatic
invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
, and other wildlife. A 2013 Dutch study found that water containing allowable concentrations of imidacloprid had 50% fewer invertebrate species compared with uncontaminated water. A later study found the analysis was confounded with other co-occurring insecticides and did not show imidacloprid directly affected invertebrate diversity. A 2014 review took a broader look at the ecological impact of neonicotinoids and
fipronil Fipronil is a broad-spectrum insecticide that belongs to the phenylpyrazole chemical family. Fipronil disrupts the insect central nervous system by blocking the ligand-gated ion channel of the GABAA receptor and glutamate-gated chloride (GluCl ...
, finding negative effects on invertebrates, but not microbes or fish. Although not yet conclusive, there is increasing evidence that neonicotinoids can have negative effects on pollinating insects other than bees, including
monarch butterflies The monarch butterfly or simply monarch (''Danaus plexippus'') is a milkweed butterfly (subfamily Danainae) in the family Nymphalidae. Other common names, depending on region, include milkweed, common tiger, wanderer, and black-veined brown. It ...
.


See also

*
Decline in amphibian populations Since the 1980s, decreases in amphibian populations, including population decline and localized mass extinctions, have been observed in locations all over the world. These declines are known as one of the most critical threats to global biodiversi ...
*
Decline in insect populations An increasing number of scientific studies are reporting substantial declines in insect populations worldwide. Most commonly, the declines involve reductions in abundance, though in some cases entire species are going extinct. The declines are f ...


References


External links

* {{Authority control Insecticides