Australian Grape & Wine gains approval for temporary changes to Ontario’s MRL for Phosphorous Acid

Recent weather conditions in certain regions have unfortunately been conducive to downy mildew infection.

Phosphorous acid is a registered fungicide that is commonly used to prevent or control downy mildew; however, residues in wine are to be expected if it is used at any time during the growing season.

Although Australia has a maximum residue limit (MRL) for phosphorous acid in grapes of 200 ppm, various export markets have no, or very low, tolerance levels regarding phosphorous acid residues. Care should therefore be exercised if intending to use phosphorous acid in relation to products destined for export.

Each Canadian province, with the exception of Alberta, has a government-controlled liquor control board which regulates liquor licensing, labelling/packaging and importation standards in that province. Accordingly, despite the fact that Canada’s MRL for phosphorous acid is 21 ppm, the Liquor Control Board of Ontario (LCBO) has historically prescribed a very low tolerance (0.1 ppm) in relation to phosphorous acid. As such, it has generally been recommended that phosphorous acid not be used in relation to products destined for Ontario.

Pleasingly, the LCBO has, following consultation with Australian Grape & Wine, Australian Wine Research Institute (AWRI) and Wine Australia, agreed to temporarily extend its MRL for phosphorus acid to match the Canadian MRL, subject to its further review.

As such, the LCBO will accept Australian wines produced from vintages leading up to and including the 2023 vintage, provided that:

  • any phosphorous acid residues found in the finished, commercial wines imported by the LCBO are well within the maximum residue level of 21 ppm expressed as phosphorous acid (or 30 ppm expressed as fosetyl-Al);
  • prior to export, prospective Australian exporters test their wines (that have been produced from grapes that have had phosphorous acid applied) to ensure compliance with the relevant MRL; and
  • exporters provide the LCBO with a copy of the relevant Certificate of Analysis, upon the LCBO’s request.

Exporters should note that the changes to the LCBO’s MRL for phosphorous acid is temporary only and is subject to its further review.

Further, despite these temporary changes, the relevant MRL in Ontario (and other major export markets) remains relatively low, and grapegrowers and winemakers should exercise care if intending to use phosphorous acid this growing season in relation to grapes eventually destined for export.

We strongly recommend growers engage with their wine producers before making decisions on use of Phosphorous acid.

Further guidance in relation to the use of phosphorous acid is available on the AWRI’s website and in the AWRI’s “Dog Book”. For further information concerning the exporting of Australian wine to Ontario, please consult Wine Australia’s Export Market Guide – Canada or contact

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