Nov. 29, 2017
Pest Control Products Act, Health Canada’s Pest Management Regulatory Agency (PMRA) has notified the WTO that proposed Maximum Residue Levels (MRLs) for Spirotetramat in crops such as stone fruits, tree nuts, carrot roots, sugar beet roots and asparagus are to be implemented. Submitting comments from WTO members are due within 75 days of publication, November 2, 2017.
Spirotetramat is the ISO common name for cis-3-(2,5-dimethylphenyl)-4-hydroxy-8-methoxy-1-azaspiro[4.5]dec-3-en-2-one and it is also known by the manufacturer’s experimental name BYI08330. It belongs to the chemical class of ketoenols which can translocate in the phloem and xylem of plants. This compound acts as an inhibitor of acetyl-CoA carboxylase against a broad spectrum of sucking insects. Due to no cross-resistance to other conventional insecticides and no negative impact on beneficial arthropods, it is widely used in various crops. Nevertheless, Spirotetramat is considered to be an eye and skin irritant in animals and humans. BYI08330-enol-Glc, BYI08330-ketohydroxy, BYI08330-monohydroxy, and BYI08330-enol-glucoside are the main metabolites of Spirotetramat in plants. To express the residue of BYI08330 and its metabolites, the regulations require them to be reported as Spirotetramat equivalents.
In order to ensure food safety for consumers many organizations and countries, such as Codex, EU, US, Japan, and Canada, have established maximum residue limits (MRLs) for pesticides in food commodities based on field trial data. In Canada, either Codex MRLs for Spirotetramat used for internal food trade do not cover domestically-produced and imported foods including carrot roots, sugar beet roots, and asparagus, or there is no Canadian scientific data studying their toxicities in stone fruits and tree nuts. As a result, Health Canada’s PMRA has conducted its own risk assessment to determine whether the levels of Spirotetramat residue detected in these products are harmful to human health. Subsequently, Canada’s proposed MRLs for these products have been set and the WTO notified, see Table 1. To date, Spirotetramat and its metabolites in crops can be extracted by using the QuEChERS method and analyzed by the Liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique.
What do the changes mean?
This update has the potential to affect agricultural producers, food manufacturers, and pesticide manufacturers. Any individual crop destined for Canada, must not be found to have Spirotetramat residues in excess of the MRLs in Table 1. To ensure compliance with food safety regulation, food producers should seek professional advice.
Table 1: Maximum residue limits for Spirotetramat in crops
||PARTS PER MILLION (PPM)
||Carrot roots, sugar beet roots