Proposed Maximum Residue Limit PMRL2017-09 Penthiopyrad

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Pest Management Regulatory Agency
11 April 2017
ISSN: 1925-0843 (PDF version)
Catalogue number: H113-24/2017-9E-PDF (PDF version)

Under the authority of the  Pest Control Products Act, Health Canada’s Pest Management Regulatory Agency (PMRA) has concluded that the use on barley on the product label of Vertisan® Fungicide, containing technical grade penthiopyrad, is acceptable. The specific uses approved in Canada are detailed on the label of Vertisan® Fungicide, Pest Control Products Act Registration Number 30332.

The evaluation of this penthiopyrad 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 MRLs for penthiopyrad is being conducted via this document (see Next Steps). A summary of the field trial data used to support the proposed MRLs can be found in Appendix I.

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

The proposed MRLs, to replace MRLs already established for penthiopyrad, are as follows.

Table 1 Proposed Maximum Residue Limits for Penthiopyrad
Common Name Residue Definition MRL (ppm)Table 1 footnote 1 Food Commodity
Penthiopyrad N-[2-(1,3-dimethylbutyl)-3-thienyl]-1-methyl-3-(trifluoromethyl)-1H-pyrazole-4-carboxamide 2.0 Barley branTable 1 footnote 2
0.3 BarleyTable 1 footnote 2
Table 1 footnote 1

ppm = parts per million


Table 1 footnote 2

An MRL of 0.3 ppm for barley and 2.0 ppm for barley bran are proposed to replace the current MRL of 0.15 ppm and 0.9 ppm, respectively


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

MRLs may vary from one country to another for a number of reasons, including differences in pesticide use patterns and the locations of the crop field trials used to generate residue chemistry data.

Table 2 compares the MRLs proposed for penthiopyrad in Canada with corresponding American tolerances and Codex MRLs.Footnote 1.2 American tolerances are listed inthe Electronic Code of Federal Regulations, 40 CFR Part 180, by pesticide. A listing of established Codex MRLs is available on the Codex Alimentarius Pesticide Residues in Food and Feed website, by pesticide or commodity.

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

Table 2 Comparison of Canadian MRLs, American Tolerances and Codex MRLs (where different)
Food Commodity Canadian MRL (ppm) American Tolerance (ppm) Codex MRL (ppm)
Barley grains 0.3 Barley grains: 0.15 Barley: 0.2
Barley bran 2.0 Barley milled products: 0.9

Next Steps

The PMRA invites the public to submit written comments on the proposed MRLs for penthiopyrad 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 MRLs. Comments received will be addressed in a separate document linked to this PMRL. The established MRLs 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 Limits

Residue data for penthiopyrad in barley were submitted to support the domestic use of Vertisan® Fungicide on barley. Previously reviewed residue data from field trials conducted in/on barley and processing data in/on wheat were also reassessed in the framework of this petition.

Maximum Residue Limits

The recommendation for maximum residue limits (MRLs) for penthiopyrad was based upon the submitted field trial data, and the guidance provided in the OECD MRL Calculator. Table A1 summarizes the residue data used to calculate the proposed MRLs for barley.

Table A1 Summary of Field Trial and Processing Data Used to Support MRLs
Commodity Application Method/ Total Application Rate
(g a.i./ha)Table 1 footnote 1.1
arvest Interval (days) Lowest Average Field Trial Residues
Highest Average Field Trial Residues
Experimental Processing Factor
Barley grain Foliar broadcast
677 - 732
33-76 < 0.01 0.24 7.7×
(wheat bran)

Table 1 footnotes

Table 1 footnote 1

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


Following the review of all available data, MRLs as proposed in Table 1 are recommended to cover residues of penthiopyrad. Residues of penthiopyrad in these crop commodities at the proposed MRLs will not pose an unacceptable risk to any segment of the population, including infants, children, adults and seniors.

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