Sulfoxaflor

Sulfoxaflor, also marketed as Isoclast[1] is a systemic insecticide which acts as an insect neurotoxin and is a member of a class of chemicals called sulfoximines which act on the central nervous system of insects.

Sulfoxaflor
Names
IUPAC name
[Methyl(oxo){1-[6-(trifluoromethyl)-3-pyridyl]ethyl}-λ6-sulfanylidene]cyanamide
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.234.961
UNII
Properties
C10H10F3N3OS
Molar mass 277.27 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Mechanism of action

Sulfoxaflor is a systemic insecticide, acts as a neurotoxin to affected insects, and kills through contact or ingestion.

Sulfoxaflor is classified for use against sap-feeding insects as a sulfoximine, which is a sub-group of insecticides that act as nicotinic acetylcholine receptor (nAChR) competitive modulators.[2][3] Sulfoxaflor binds to nAChRs in place of acetylcholine. Sulfoxaflor binding causes uncontrolled nerve impulses resulting in muscle tremors followed by paralysis and death.[2]

Other nAChR competitive modulator sub-groups that bind differently on the receptor than sulfoximines include neonicotinoids, nicotine, and butenolides.[4][2][5]

Because sulfoxaflor binds much more strongly to insect neuron receptors than to mammal neuron receptors, this insecticide is selectively more toxic to insects than mammals.[6]

Non-target effects

Application is only recommended when pollinators are not likely to be present in an area as sulfoxaflor is highly toxic to bees if they come into contact with spray droplets shortly after application; toxicity is reduced after the spray has dried.[3]

Registration

On May 6, 2013, the United States Environmental Protection Agency (EPA) approved the first two commercial pesticide products that contain sulfoxaflor, marketed under the brand names "Transform" and "Closer", to the Dow Chemical Corporation.

On September 10, 2015 the U.S. 9th Circuit Court of Appeals overturned the EPA's approval of sulfoxaflor, citing insufficient evidence from studies regarding bee health to justify how sulfoxaflor was approved.[7][5] Beekeepers and environmental groups supported the decision, saying that the EPA must assess the health of entire hives, not just individual bees.[8]

On October 14, 2016, the United States Environmental Protection Agency (EPA) approved new registrations for sulfoxaflor, "Transform" and "Closer", to the Dow Chemical Corporation.

Previously, the Dow Chemical Corporation owned and sold these products. However, as of June, 2019, the agricultural wing of the Dow Chemical Corporation was split into an independent public corporation called Corteva Agriscience, who now sells the sulfoxaflor-based pesticides. [9]

On July 12th, 2019, the EPA announced it will allow the use of sulfoxaflor, citing new studies that show lower harm levels to bees than other available pesticides.[9] The EPA concluded that sulfoxaflor would lessen the danger to bees since industry-backed studies assessed it dissipated more quickly and required few applications than other pesticides.[10]

Sulfoxaflor is currently registered in 47 countries, including US, Canada, Mexico, Argentina, Chile, India, China and Australia.[11] The registration of Closer and Transform in France was overturned by a court decision in November, 2017. [12]

See also

References
  1. Isoclast™ active (sulfoxaflor) Dow Technical Bulletin msdssearch.dow.com (retrieved 10 June 2019)
  2. Casida, J.E.; Durkin, K.A. (2013). "Neuroactive insecticides: targets, selectivity, resistance, and secondary Effects". Annual Review of Entomology. 58: 99–117. doi:10.1146/annurev-ento-120811-153645. PMID 23317040.
  3. "Sulfoxaflor" (PDF). mda.state.mn.us. Retrieved 11 June 2019.
  4. "IRAC Mode of Action Classification Scheme". irac-online.org. Retrieved 11 June 2019.
  5. "Court rejects US approval of sulfoxaflor pesticide". Royal Society of Chemistry. 2015-09-16. Retrieved 2015-09-17.
  6. Tomizawa, M.; Casida, J.E. (2003). "Selective toxicity of neonicotinoids attributable to specificity of insect and mammalian nicotinic receptors". Annual Review of Entomology. 48: 339–64. doi:10.1146/annurev.ento.48.091801.112731. PMID 12208819.
  7. "Court revokes approval of insecticide, citing 'alarming' decline in bees". LA Times. 2015-09-10. Retrieved 2015-09-14.
  8. Philpott, Tom (11 September 2015). "Federal Court to EPA: No, You Can't Approve This Pesticide That Kills Bees". Mother Jones. Retrieved 19 September 2015.
  9. Knickmeyer, Ellen (12 July 2019). "EPA restores broad use of pesticide opposed by beekeepers". Market Beat. Retrieved 12 July 2019.
  10. Dennis, Brady (12 July 2019). "EPA to allow use of pesticide considered 'very highly toxic' to bees". Washington Post. Retrieved 28 June 2020.
  11. https://iaspub.epa.gov/apex/pesticides/f?p=105:6:::NO::P6_XCHEMICAL_ID:3967
  12. French court suspends two Dow pesticides over potential harm to bees 24 November 2017 reuters.com, accessed 11 June 2019
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