From labels and weed guides
Best herbicides for canada thistle in seed corn
For canada thistle in seed corn, the weed guides list 7 active-ingredient groups rated good or excellent, after checking that the products are labeled for seed corn.
Canada Thistle control in seed corn
Every listed product is labeled for seed 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, 7 active-ingredient groups are rated good or excellent for canada thistle in seed corn.
| Example product | Active ingredients | MOA group | Ratings checked |
|---|---|---|---|
| Staunch II EPA 62719-679-55467; same active ingredients on 4 other branded products | acetochlor, clopyralid, and flumetsulam | 2, 4, 15 | ND Weed Guide 2026: G-E (PDF) |
| 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) |
| Distinct EPA 7969-150; same active ingredients on 2 other branded products | dicamba and diflufenzopyr | 4, 19 | ND Weed Guide 2026: G (PDF) |
| Hornet WDG EPA 62719-315; same active ingredients on 2 other branded products | clopyralid and flumetsulam | 2, 4 | ND Weed Guide 2026: G-E (PDF) |
| DiFlexx DUO EPA 264-1184 | dicamba and tembotrione | 4, 27 | ND Weed Guide 2026: G (PDF) |
| Enlist Duo EPA 62719-649 | 2,4-d and glyphosate | 4, 9 | 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.
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Sources
Data from current labels and weed guides. Last source update: 2026-07-14.