With the PMRA having reviewed numerous potato products, it’s important to keep track of what you can and can’t use anymore.

Over the past few years, Health Canada’s Pest Management Regulatory Agency (PMRA) has completed numerous reviews of active ingredients used in products by the potato industry. While these reviews have been published and shared widely, it’s easy to forget them by the time it comes around for them to go into effect.

“The challenge that we have is that the final decision gets published, and then there’s an implementation time period. So, it’s news when it first happens. But then the next time that you really have to be thinking about it again is that date when those changes that were announced actually come into force at the farm level,” Tracy Shinners-Carnelley, vice president of research, quality and sustainability at Peak of Market, said during a presentation at Manitoba Potato Production Days on Jan. 25, 2023.

Tracy Shinners-Carnelley headshot
Tracy Shinners-Carnelley, vice president, research and quality with Peak of the Market in Manitoba. Photo: Tracy Shinners-Carnelley

Here are a few changes to keep in mind for this growing season, as shared by Shinners-Carnelley:

  • As of Nov. 19, 2022, foliar applications of mancozeb, the active ingredient of Manzate and Dithane, are limited to eight per growing season, with the re-entry interval now being 0.5 days and the pre-harvest interval three days. The 2023 crop year will be the last year of use for mancozeb seed piece treatments.
  • The re-evaluation of chlorothalonil, the active ingredient of Bravo, has resulted in the implementation of additional measures to mitigate exposure of mixers, loaders, applicators, and post-applications workers. It can only be used a maximum of three times per season for potatoes. The re-entry intervals were increased to three days for scouting, 19 days for rogueing, and 23 days for handset irrigation. There are also requirements now for vegetative filter strips.
    • In February 2022 the PMRA published a special review decision where it was proposed all uses of chlorothalonil, besides for greenhouse ornamental use, would no longer be allowed. The Canadian Potato Council submitted a response in May 2022 during the comment period. The final decision is pending.
  • Metiram and captan were re-evaluated and are still allowed to be used with new label modifications in place.
  • Clothianidin, the active ingredient of Titan, has had its in-furrow application use cancelled as of March 31, 2023.
  • Thiamethoxam, the active ingredient of Actara, has had its soil drench application cancelled as of March 31, 2023.
  • As of March 31, 2023, imidacloprid, sold as Admire, has had its soil drench application cancelled and foliar applications are reduced to once per season.
  • Lambda-cyhalothrin, the active ingredient of Matador and Silencer, is still allowed for use on potatoes, but its use for livestock feed was cancelled. This has led registrants to start to withdraw it for sale in Western Canada.
  • As of May 2024, all uses of pymetrozine, the active ingredient of Fulfill, will no longer be allowed.

Related Articles

MPPD Celebrates 50 Years of Potato Memories

Positive PMRA Potato Insecticide Ruling

Shrinking Toolbox