Proposed Maximum Residue Limit PMRL2020-10, Halauxifen-methyl

Notice to the reader:

The online consultation is now closed.

Pest Management Regulatory Agency
23 July 2020
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2020-10E-PDF (PDF version)

Under the authority of the Pest Control Products Act, Health Canada's Pest Management Regulatory Agency (PMRA) has concluded that the addition of new uses on oats to the product label of Paradigm Herbicide, containing technical grade halauxifen-methyl and florasulam, is acceptable. The specific uses approved in Canada are detailed on the label of Paradigm Herbicide, Pest Control Products Act Registration Number 31304.

The evaluation of this halauxifen-methyl application indicated that the end-use product has value and the human health and environmental risks associated with the new uses are acceptable.

Before registering a pesticide for food use in Canada, the PMRA must determine the quantity of residues that are likely to remain in or on the food when the pesticide is used according to label directions and that such residues will not be a concern to human health. This quantity is then legally established as a maximum residue limit (MRL). An MRL applies to the identified raw agricultural food commodity as well as to any processed food product that contains it, except where separate MRLs are specified for the raw agricultural commodity and a processed product made from it.

Consultation on the proposed MRL for halauxifen-methyl is being conducted via this document (see Next Steps). A summary of the field trial data used to support the proposed MRL can be found in Appendix I.

For florasulam, the previously established MRL of 0.01 ppm in/on oats is sufficient to cover residues resulting from this new use and is, therefore, unaffected by this MRL action.

To comply with Canada's international trade obligations, consultation on the proposed MRL is also being conducted internationally by notifying the World Trade Organization, as coordinated by the Canada's Notification Authority and Enquiry Point.

The proposed MRL, to be added to the MRLs already established for halauxifen-methyl, is as follows.

Table 1: Proposed Maximum Residue Limit for halauxifen-methyl
Common name Residue definition MRL (ppm)Table 1: Tablenote 1 Food commodity

Methyl 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)-2-pyridinecarboxylate

0.01 Oats

Table 1: Tablenote 1

Table 1: Tablenote 1

ppm = parts per million

Return to Table 1: Footnote 1 referrer

MRLs established in Canada may be found using the Maximum Residue Limit Database on the Maximum Residue Limits for Pesticides webpage. The database allows users to search for established MRLs, regulated under the Pest Control Products Act, both for pesticides or for food commodities.

International situation and trade implications

Currently, there is no American tolerance established for halauxifen-methyl on oats inthe Electronic Code of Federal Regulations, 40 CFR Part 180, nor are there Codex MRLsFootnote 1 listed for halauxifen-methyl on any commodity on the Codex Alimentarius Pesticide Index webpage.

Next steps

The PMRA invites the public to submit written comments on the proposed MRL for halauxifen-methyl up to 75 days from the date of publication of this document. Please forward your comments to Publications. The PMRA will consider all comments received before making a final decision on the proposed MRL. Comments received will be addressed in a separate document linked to this PMRL. The established MRL will be legally in effect as of the date that they are entered into the Maximum Residue Limit Database.

Appendix I

Summary of field trial data used to support the proposed maximum residue limit

Australian residue data for halauxifen-methyl in/on oats were submitted to support the domestic use of Paradigm Herbicide on oats. Previously reviewed Canadian residue data in/on cereals (wheat, barley and field corn) and a confined crop rotational study were re-assessed to determine the acceptability of the preharvest interval in the framework of this petition. In addition, a processing study in treated wheat was also re-assessed to determine the potential for concentration of residues of halauxifen-methyl into processed cereal commodities.

Maximum residue limit

The recommendation for a maximum residue limit (MRL) for halauxifen-methyl was based upon the submitted field trial data, including Australian data conducted at exaggerated rates, and the guidance provided in the OECD MRL Calculator. Table A1 summarizes the residue data used to determine the proposed MRL for oats.

Table A1: Summary of Field Trial and Processing Data Used to Support the MRL
Commodity Application method/
Total application rate
(g a.i./ha/season)Table A-1: Footnote 1
Preharvest interval (days) Lowest average field trial residues (ppm) Highest average field trial residues (ppm) Experimental processing factor

Postemergent, foliar ground application/9.5–10.3

Postemergent, foliar ground application/19.0–20.3

73–116 <0.01 <0.01 No quantifiable residues observed at exaggerated rates in the wheat processing study.
Table A1 Footnote 1

g a.i./ha = grams of active ingredient per hectare

Table A1 Return to footnote 1 referrer

Following the review of all available data, MRLs as proposed in Table 1 are recommended to cover residues of glufosinate-ammonium. Residues of glufosinate-ammonium in these crop commodities at the proposed MRLs will not pose any health risks of concern to any segment of the population, including infants, children, adults and seniors.


Footnote 1

The Codex Alimentarius Commission is an international organization under the auspices of the United Nations that develops international food standards, including MRLs.

Return to footnote 1 referrer

Report a problem or mistake on this page
Please select all that apply:

Thank you for your help!

You will not receive a reply. For enquiries, contact us.

Date modified: