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Gowan Canada Group 8 Herbicides Now Classified as Group 15

Winnipeg, Manitoba, December 9, 2021

To Our Valued Customers:

We would like to update you on a few changes that will be made at Gowan Canada based on recent regulatory and industry guideline modifications.

Recently, HRAC (Herbicide Resistance Action Committee) and WSSA (Weed Science Society of America) made changes to their chemical groupings, which affect two Gowan Canada active ingredients: Triallate (Avadex® MicroActiv, Avadex Liquid EC, Fortress MicroActiv®) and EPTC (Eptam®).  HRAC and WSSA determined that the mode of action previously represented as Group 8 has a similar mode of action to Group 15 and eliminated Group 8 which included Triallate and EPTC. 

Although the modes of action of Triallate and EPTC have been relocated to Group 15, rotation of Triallate and EPTC with historical Group 15 herbicides is still aligned with HRAC and WSSA recommendations for resistance management. 

Group 15 covers multi-enzyme modes of action with a complex pattern of substrate specificity, and combinations or sequences of products containing active ingredients from the former Group 8 and new Group 15 are still supported by HRAC and WSSA.  In other words, the efficacy and pattern of use in rotating these chemistries has not changed and they remain as effective as always.  

More information regarding this update can be reviewed at

Over the course of the next year, we will be updating our product labels and literature to reflect these group changes.  Again, there is no change to the products’ formulations, activity, or site of activity.

Please contact your local Gowan Canada Representative if you have questions or concerns.