19 November 2008
ISBN: 978-1-100-10741-7 (978-1-100-10742-4)
Cat. No.: H113-24/2008-31E (H113-24/2008-31E-PDF)

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On 26 February 2008, Health Canada's Pest Management Regulatory Agency (PMRA) published and sought comments on the Proposed Maximum Residue Limit PMRL2008-01 for Coumaphos. A comment was received suggesting the need to establish an MRL for beeswax, as discussed in the corresponding Established Maximum Residue Limit EMRL2008-18, Coumaphos, published on 29 August 2008 which established MRLs for honey and honeycomb.

The PMRA agreed with the need for a beeswax MRL and consultation on the proposed MRL for coumaphos is being conducted via this document (see Next Steps). The supporting summary residue trial data is attached as Appendix I.

The proposed MRL for coumaphos in Canada in or on food, to be added to those already legally established, is as follows.

Table 1: Proposed Maximum Residue Limits for Coumaphos

Common Name	Residue Definition	MRL (ppm)	Food Commodity
Coumaphos	O-(3-chloro-4-methyl-2-oxo-2H-1-benzopyran-7yl) O,O-diethyl phosphorothioate, including the oxygen analog O-(3-chloro-4-methyl-2-oxo-2H-1benzopyran-7-yl) O,O-diethyl phosphate	1.0	Beeswax

A complete list of all MRLs established in Canada can be found on the PMRA's MRL webpage.

International Situation and Trade Implications

Currently, an American tolerance (listed in  40 CFR Part 180 by pesticide). has not been established for coumaphos in or on beeswax and Codex MRLs¹ have not been established for coumaphos on any commodity ( Codex MRLs searchable by pesticide or commodity).

Next Steps

The PMRA invites the public to submit written comments on the proposed MRLs for acequinocyl up to 75 days from the date of publication of this document. Please forward your comments to Publications (see contact information on the cover page of this document). The PMRA will consider all comments received before making a final decision on the proposed MRLs for acequinocyl and posting an Established Maximum Residue Limit (EMRL) document on the PMRA's website.

Appendix I

Table 1 summarizes the Canadian Checkmite + Beehive Pest Control Strip (Pest Control Products Act Registration Number 27147) use pattern for beehives. Additional specific details are available on the product label.

Table 1 Summary of Canadian Checkmite + Beehive Pest Control Strip Use Pattern

Commodity	Method/Timing	Rate, % (w/w)	Total Rate for Varroa Mite, % (w/w)	Harvest Procedures
Beehive	Impregnated strips placed in the hive for 45 days with honey supers removed	Each of four colonies treated with one 10 % strip	1x10 % per colony	Honey supers may be replaced 14 days after strips are removed

The trials on beehives conducted in the United States in 2000 demonstrated that, when treated at various rates, residues of coumaphos and coumaphos oxygen analog in beeswax were each <0.5 ppm, the limit of quantification (LOQ) of the analytical method. Table 2 summarizes the results of the field trials.

Table 2 Summary of Residue Data From Commodity Field Trials

Commodity	Total Rate for Varroa Mite, % (w/w)	Number of Beeswax Samples	Residue Levels (ppm)
			Min.	Max.
Coumaphos
Beewax	Either 2 × 5% strips, 1 × 7.5 % strip, 1 × 10% strip, or 2 × 10 % strips	18	<0.5	<0.5
Coumaphos Oxygen Analog
Beeswax	Either 2 × 5% strips, 1 × 7.5 % strip, 1 × 10% strip, or 2 × 10 % strips	18	<0.5	<0.5

On the basis of the submitted data, a MRL of 1.0 ppm is proposed to cover the combined residues of coumaphos and the oxygen analog in beeswax when Checkmite + Beehive Pest Control Strips are used in accordance with the Canadian use pattern.

References

¹ Codex is an international organization under the auspices of the United Nations that develops international food standards, including MRLs.