From labels and weed guides
Group 27 herbicides for canada thistle in field corn
There are 4 Group 27 active-ingredient groups rated good or excellent for canada thistle in field corn, with products labeled for field corn.
Group 27 mode of action (MOA) options
Group 27 is a herbicide mode of action (MOA) group. Treat it as one resistance-management check, not as the whole program.
Every listed product is labeled for field corn. Ratings are shown when each weed guide that rates this weed stays at good or excellent for the active-ingredient group. If a guide gives a range, the weaker end of the range has to be good or excellent.
Based on 1 weed guide, 4 active-ingredient groups are rated good or excellent for canada thistle in field corn.
| Example product | Active ingredients | MOA group | Ratings checked |
|---|---|---|---|
| Orador EPA 91234-324; same active ingredients on 3 other branded products | acetochlor, clopyralid, and mesotrione | 4, 15, 27 | ND Weed Guide 2026: G-E (PDF) |
| DiFlexx DUO EPA 264-1184 | dicamba and tembotrione | 4, 27 | ND Weed Guide 2026: G (PDF) |
| Halex GT EPA 100-1282 | glyphosate, mesotrione, and metolachlor | 9, 15, 27 | ND Weed Guide 2026: G-E (PDF) |
| IMPACTZ EPA 5481-612 | atrazine and topramezone | 5, 27 | ND Weed Guide 2026: G (PDF) |
Rating legend: E=excellent, G=good, F=fair, P=poor, N=no control. A range such as G-E means the guide gives a range; 'a' after a rating (e.g., Ga) means the guide assumes its recommended additive.
Build the full program
Check crop, timing, state, resistance, and rotation in one plan before you make a recommendation.
Sources
Data from current labels and weed guides. Last source update: 2026-07-14.