Sulfentrazone

In 1985, scientists at FMC Corporation filed patents on a new class of herbicides containing a triazolinone ring.{{cite patent |country=US |number=4818275|status=patent |gdate=1989-04-04 |fdate=1986-12-31 |pridate=1985-12-20 |invent1 =Theodoridis, George |title=Herbicidal aryl triazolinones |assign1=FMC Corporation}} Sulfentrazone was subsequently developed for market under the code number F6285, with first sales in 1991{{cite book |doi=10.1021/bk-1992-0504.ch014 |chapter=Synthesis and Herbicidal Properties of Aryltriazolinones |title=Synthesis and Chemistry of Agrochemicals III |series=ACS Symposium Series |year=1992 |last1=Theodoridis |first1=George |last2=Baum |first2=Jonathan S. |last3=Hotzman |first3=Frederick W. |last4=Manfredi |first4=Mark C. |last5=Maravetz |first5=Lester L. |last6=Lyga |first6=John W. |last7=Tymonko |first7=John M. |last8=Wilson |first8=Kenneth R. |last9=Poss |first9=Kathleen M. |last10=Wyle |first10=Michael J. |volume=504 |pages=134–146 |isbn=9780841224735 }} and achieving registration in the US in 1997, branded Authority.{{ Cite web| url=https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_PC-129081_27-Feb-97.pdf |title=Sulfentrazone Factsheet | work=United States EPA |date=1997-02-27 |access-date=2021-04-19}} Other compounds now in the triazolinone class include amicarbazone and carfentrazone.{{cite web|url=http://www.alanwood.net/pesticides/class_herbicides.html#triazolone_herbicides |title=triazolone herbicides |website=alanwood.net |access-date=2021-04-12}}

The effects visible on whole plants are chlorosis and desiccation caused by the inhibition of the enzyme protoporphyrinogen oxidase, which leads to an accumulation of protoporphyrin IX in the plant cells. This is a potent photosensitizer which activates oxygen, leading to lipid peroxidation. Both light and oxygen are required for this process to kill the plant.{{cite book |doi=10.1007/978-3-642-58633-0_11 |chapter=Herbicidal Efficacy of Protoporphyrinogen Oxidase Inhibitors |title=Peroxidizing Herbicides |year=1999 |last1=Nagano |first1=Eiki |pages=296–299 |isbn=978-3-642-63674-5 }}

In the United States, the Environmental Protection Agency (EPA) is responsible for regulating pesticides under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), the Food Quality Protection Act (FQPA) and the Pesticide Registration Improvement Act (PRIA). A pesticide can only be used legally according to the directions on the label that is included at the time of the sale of the pesticide. The purpose of the label is "to provide clear directions for effective product performance while minimizing risks to human health and the environment". A label is a legally binding document that mandates how the pesticide can and must be used and failure to follow the label as written when using the pesticide is a federal offence.{{cite web|url=https://www.epa.gov/pesticide-registration/about-pesticide-registration |title=About Pesticide Registration |date=27 February 2013 |publisher=US EPA |access-date=2021-04-19 }}{{cite web|url=https://www3.epa.gov/pesticides/chem_search/ppls/091234-00009-20151210.pdf |author=US EPA|website=www3.epa.gov|title=Sulfentrazone 4 Herbicide |access-date=2021-04-19}}

The label includes use for removal of sedges and newly emerged broadleaf weeds including purple and yellow nutsedge, Kyllinga, plantain, clover, spurge, woodsorrel, knotweed, chickweed, curly dock, wild onion, and wild garlic. It is also effective on many grasses including Poa annua, Poa trivialis, creeping bentgrass, fine & tall fescue, perennial ryegrass, Kentucky & rough bluegrass, bahiagrass, Bermuda grass, buffalograss, carpetgrass, centipedegrass, kikuyugrass, seashore paspalum, St. Augustine grass, and zoysiagrass.

Sulfentrazone can be used both pre- and post-emergence and is rapidly metabolised by soybean at the methyl group of the triazolinone ring, which confers a level of safety to that crop.{{cite journal |last1=Dayan|first1= F.|last2=Weete|first2= J.|last3=Duke|first3=S.|last4= Hancock|first4=H.|date=1997|title= Soybean (Glycine max) cultivar differences in response to sulfentrazone|journal=Weed Science|volume=45|issue=5|pages=634–641|jstor= 4045886|url=https://www.jstor.org/stable/4045886 }}

The estimated annual use of sulfentrazone in US agriculture is mapped by the US Geological Service and shows that in 2017, the latest date for which figures are available, approximately {{convert|3800000|lb|kg}} were applied — mainly in soybean.{{cite web |url=https://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=2017&map=SULFENTRAZONE&hilo=L&disp=Sulfentrazone |title=Estimated Agricultural Use for Sulfentrazone, 2017 |author=US Geological Survey |access-date=2021-04-19 }} The compound is not registered for use in the European Union, although another triazolinone, carfentrazone-ethyl, is available there.{{cite web |url=http://sitem.herts.ac.uk/aeru/ppdb/en/Reports/123.htm |title=Carfentrazone-ethyl |publisher=University of Hertfordshire |author=Pesticide Properties Database |access-date=2021-04-19}} Sulfentrazone also has uses outside agriculture: it controls vegetation on roadside verges and railroads.{{cite web |url= https://wsdot.wa.gov/sites/default/files/2008/01/25/Herbicides-factsheet-Sulfentrazone.pdf |title=Sulfentrazone: Roadside Vegetation Management |work=Washington State DOT |date=2017 |access-date=2021-04-19}}{{cite web |url=https://www3.epa.gov/pesticides/chem_search/ppls/000279-03282-20200417.pdf |title=Sulfentrazone ROW herbicide |work=US EPA label |date=2020-04-17 |access-date=2021-04-19}} The active ingredient has been sold alone or in combination with other herbicides under a large number of brand names including Dismiss, Solitaire and Spartan. Suppliers and brand names in the United States are listed in the National Pesticide Information Retrieval System.{{cite web |url=http://npirspublic.ceris.purdue.edu/ppis/default.aspx |author=NPIRS Public |title=Search Federal Pesticide Products }}

The LD₅₀ of sulfentrazone is more than 2800 mg/kg (rats, oral), which means that it is of low toxicity by oral ingestion. The US Code of Federal Regulations records the maximum residue tolerances in various food products.{{cite web|url=https://ecfr.federalregister.gov/on/2021-04-19/title-40/chapter-I/subchapter-E/part-180/subpart-C/section-180.498|title=Sulfentrazone; tolerances for residues|website=ecfr.federalregister.gov|date=1997-03-10|access-date=2021-04-19}}

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{{Herbicides}}

Category:PPO herbicides

Category:Organofluorides

Category:Sulfonamides

Category:Chloroarenes

Category:Group 14 herbicides