Fluxapyroxad is a broad-spectrum
pyrazole-
carboxamidefungicide used on a large variety of commercial crops.[2][3] It stunts fungus growth by inhibiting the
succinate dehydrogenase (SQR) enzyme.[3][4] 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, especially when combined with
pyraclostrobin.[1] There is also concern that some fungi may develop resistance to fluxapyroxad.[5][6]
Fluxapyroxad is a succinate dehydrogenase inhibitor (SDHI).[5] It interferes with a number of key fungal life functions, including spore germination,
germ tube growth,
appresoria formation and
mycelium 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.[2]
Crops
Fluxapyroxad is commonly used as a fungicide for grains,
row crops, vegetable crops, and fruit trees (
pome and
prunus), including:[8][9][10]
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.[3][17][18] The primary target organ for fluxapyroxad exposure is the liver.[8]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.[8] Fluxapyroxad was found "not likely" to be
carcinogenic in humans and there was no evidence of
neurotoxicity.[8]
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.[8] The EPA is currently considering reducing those tolerances.[19]
Registration and approval
Fluxapyroxad has been approved for use as a fungicide in the United States, Canada and the
European Union.[20] In the spring of 2012, fluxapyroxad, trademarked under the names Sercadis,[21]Imbrex[22] and Xemium[23] and manufactured by
BASF Corporation, was registered for use as a fungicide in the
United States. Fluxapyroxad is also one of the two active ingredients in Priaxor fungicide and Merivon fungicide, the other active ingredient being a
strobilurin called pyraclostrobin.[24]
^Veloukas, Thomas; Markoglou, Anastasios N.; Karaoglanidis, George S. (2013). "Differential Effect of SdhB Gene Mutations on the Sensitivity to SDHI Fungicides in Botrytis cinerea". Plant Disease. 97 (1): 118–122.
doi:
10.1094/pdis-03-12-0322-re.
PMID30722271.
abstract
^Walter, Harald (2016). "Fungicidal Succinate-Dehydrogenase-Inhibiting Carboxamides". In Lamberth, Clemens; Dinges, Jürgen (eds.). Bioactive Carboxylic Compound Classes: Pharmaceuticals and Agrochemicals. Wiley. pp. 405–425.
doi:
10.1002/9783527693931.ch31.
ISBN9783527339471.
^Coating barley seed with fluxapyroxad increased germination due to reduced fungal activity. Marquet, Nicolas (2012). "Nouvelles substances à la CIMA, la part belle aux SDHI". Phytoma-La Défense des végétaux. 659: 31–34.
abstract
^Amiri, A.; Heath, S. M.; Peres, N. A. (2012). "Sensitivity of Botrytis cinerea field isolates to the novel succinate dehydrogenase inhibitors fluopyram, penthiopyrad, and fluxapyroxad". Phytopathology. 102 (7 (supplement)): S4.4.
Abstract
^"Plant Disease Control".
Guide to Field Crop Protection(PDF). Carman, Manitoba: Manitoba Agriculture, Food and Rural Development (MAFRD), Government of Manitoba. 2014. pp. 307–452, page 352.
Archived(PDF) from the original on 25 October 2014.