Fluxapyroxad is a broad-spectrum pyrazole-

carboxamide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it is ...

fungicide Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, ...

used on a large variety of commercial crops.abstract
/ref> It stunts fungus growth by inhibiting the

succinate dehydrogenase Succinate dehydrogenase (SDH) or succinate-coenzyme Q reductase (SQR) or respiratory complex II is an enzyme complex, found in many bacterial cells and in the inner mitochondrial membrane of eukaryotes. It is the only enzyme that participates i ...

(SQR) enzyme. Application of fluxapyroxad helps prevent many wilts and other fungal infections from taking hold. As with other systemic pesticides that have a long chemical half-life, there are concerns about keeping fluxapyroxad out of the

groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidate ...

, especially when combined with

pyraclostrobin Pyraclostrobin is a quinone outside inhibitor ( QI)-type fungicide used in agriculture. Among the QIs, it lies within the strobilurin chemical class. Use Pyraclostrobin is used to protect ''Fragaria'', ''Rubus idaeus'', ''Vaccinium corymbosum'', ...

. There is also concern that some fungi may develop resistance to fluxapyroxad.

Biological action

Fluxapyroxad is a succinate dehydrogenase inhibitor (SDHI). It interferes with a number of key fungal life functions, including spore germination, germ tube growth,

appresoria An appressorium is a specialized cell typical of many fungal plant pathogens that is used to infect host plants. It is a flattened, hyphal "pressing" organ, from which a minute infection peg grows and enters the host, using turgor pressure capable ...

formation and

mycelium Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrate (biology), substrates. A typical single ...

growth. Specifically it interferes with the production of succinate dehydrogenase, the complex II in the mitochondrial respiration chain, which in turn interferes with the tricarboxylic cycle and mitochondrial electron transport.

Crops

Fluxapyroxad is commonly used as a fungicide for grains,

row crop A row crop is a crop that can be planted in rows wide enough to allow it to be tilled or otherwise cultivated by agricultural machinery, machinery tailored for the seasonal activities of row crops. Such crops are sown by drilling or transplanti ...

s, vegetable crops, and fruit trees (

pome In botany, a pome is a type of fruit produced by flowering plants in the subtribe Malinae of the family Rosaceae. Well-known pomes include the apple, pear, and quince. Etymology The word ''pome'' entered English in the late 14th century, and re ...

and

prunus ''Prunus'' is a genus of trees and shrubs, which includes (among many others) the fruits plums, cherries, peaches, nectarines, apricots, and almonds. Native to the North American temperate regions, the neotropics of South America, and the p ...

), including:

Fungal diseases

Fluxapyroxad provides protection against many fungal diseases. Studies have shown specific efficacy against diseases such as black point, Botrytis gray mold,

early blight ''Alternaria solani'' is a fungal pathogen that produces a disease in tomato and potato plants called early blight. The pathogen produces distinctive "bullseye" patterned leaf spots and can also cause stem lesions and fruit rot on tomato and tube ...

, and powdery mildew; however, fluxapyroxad was found to have no efficacy against

anthracnose A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticultur ...

on lentils.

Toxicity

Fluxapyroxad has a low toxicity for humans, slightly toxic after a single ingestion, and relatively non-toxic after single inhalation or topical skin contact. However, fluxapyroxad is highly toxic to fish, fresh-water and salt-water invertebrates, and to aquatic plants, as well as being toxic to small mammals. The primary target organ for fluxapyroxad exposure is the liver. ''As the dose or duration of exposure to fluxapyroxad increased, clinical chemistry changes related to liver function also occurred, followed by hepatocellular necrosis, neoplastic changes in the liver, and tumors.'' Fluxapyroxad was found "not likely" to be

carcinogen A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substan ...

ic in humans and there was no evidence of neurotoxicity. The United States Environmental Protection Agency has established tolerance amounts that are allowed to be present on consumer food. These range from 0.05 ppm on almonds and pecans to 3.0 ppm on leafy '' brassica'', and 15 ppm on other leafy vegetables. The EPA is currently considering reducing those tolerances.

Registration and approval

Fluxapyroxad has been approved for use as a fungicide in the United States, Canada and 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 ...

. In the spring of 2012, fluxapyroxad, trademarked under the names Sercadis, Imbrex and XemiumEPA Registration Number 7969-308 and manufactured by BASF Corporation, was registered for use as a fungicide in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. Fluxapyroxad is also one of the two active ingredients in Priaxor fungicide and Merivon fungicide, the other active ingredient being a strobilurin called pyraclostrobin.

References

{{DEFAULTSORT:Fluxapyroxad Fungicides Carboxamides Pyrazoles Fluoroarenes Biphenyls