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IUPAC name
methyl 2-[(2,6-dimethylphenyl)(methoxyacetyl)amino]propanoate
3D model (JSmol)
ECHA InfoCard 100.055.418 Edit this at Wikidata
EC Number
  • 260-979-7
  • InChI=1S/C15H21NO4/c1-10-7-6-8-11(2)14(10)16(13(17)9-19-4)12(3)15(18)20-5/h6-8,12H,9H2,1-5H3 ☒N
  • InChI=1/C15H21NO4/c1-10-7-6-8-11(2)14(10)16(13(17)9-19-4)12(3)15(18)20-5/h6-8,12H,9H2,1-5H3
  • CC1=C(C(=CC=C1)C)N(C(C)C(=O)OC)C(=O)COC
Molar mass 279.33 g/mol
Appearance Fine white powder
Density 1.20g/cm3 at 20 °C
Melting point 71 to 72 °C (160 to 162 °F; 344 to 345 K)[2]
Boiling point 295.9 °C (564.6 °F; 569.0 K) at 760 mm Hg
8,400 mg/L at 22 °C
log P 1.65 (octanol/water)[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Metalaxyl is an acylalanine fungicide with systemic function.[3] Its chemical name is methyl N-(methoxyacetyl)-N-(2,6-xylyl)-DL-alaninate. It can be used to control Pythium in a number of vegetable crops, and Phytophthora in peas. Metalaxyl-M or Ridomil Gold are trade names for the optically pure (-) / D / R active stereoisomer, which is also known as Mefenoxam.[4]

It is the active ingredient in the seed treatment agent Apron XL LS.[5]

The fungicide has suffered severe resistance problems. The fungicide was marketed for use against Phytophthora infestans. However, in the summer of 1980, in the Republic of Ireland, the crop was devastated by a potato blight epidemic after a resistant race of the oomycete appeared.[6] Irish farmers later successfully sued the company for their losses.[citation needed] Maximum pesticide residue limits for the EU/UK are set at 0.5 mg/kg for oranges and 1.0 mg/kg for apples.[citation needed] As early as 1998 Pythium was known to be widely developing resistance to Metalaxyl[7] which was the most effective control at the time.[7] Various Pythium populations have been known to have resistance to mefenoxam since the 1980s[8] and metalaxyl since 1984.[9] There is wide variability in resistance/sensitivity between Pythium species, with some populations showing complete ineffectiveness.[8]


  1. ^ Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 134
  2. ^ O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. 13th Edition, Whitehouse Station, NJ: Merck and Co., Inc., 2001., p. 1058
  3. ^ Sukul, P; Spiteller, M (2000). "Metalaxyl: persistence, degradation, metabolism, and analytical methods". Reviews of Environmental Contamination and Toxicology. 164. PMID 12587832.
  4. ^ Monkiedje, Adolphe; Spiteller, Michael (2002). "Effects of the phenylamide fungicides, mefenoxam and metalaxyl, on the microbiological properties of a sandy loam and a sandy clay soil". Biology and Fertility of Soils. 35 (6): 393–398. doi:10.1007/s00374-002-0485-1. S2CID 22642870.
  5. ^ "bmz10s02.pdf" (PDF). Government of Manitoba. Archived from the original (PDF) on 2007-09-30. CS1 maint: discouraged parameter (link)
  6. ^ Working on potato blight in Northern Ireland
  7. ^ a b "Survey of Pythium Isolates for Resistance to Subdue (metalaxyl)" (PDF). UMass Amherst. Retrieved 2020-11-23.
  8. ^ a b Del Castillo Múnera, Johanna; Hausbeck, Mary K. (2016). "Characterization of Pythium Species Associated With Greenhouse Floriculture Crops in Michigan". Plant Disease. American Phytopathological Society. 100 (3): 569–576. doi:10.1094/pdis-03-15-0296-re. ISSN 0191-2917.
  9. ^ Sanders, P. L. (1984). "Failure of Metalaxyl to Control Pythium Blight on Turfgrass in Pennsylvania". Plant Disease. American Phytopathological Society. 68 (1): 776. doi:10.1094/pd-68-776. ISSN 0191-2917.

External links[edit]

  • Metalaxyl in the Pesticide Properties DataBase (PPDB)
  • Metalaxyl-M in the Pesticide Properties DataBase (PPDB)