From labels and weed guides
Best herbicides for canada thistle in field corn
For canada thistle in field corn, the weed guides list 10 active-ingredient groups rated good or excellent, after checking that the products are labeled for field corn.
Canada Thistle control in field corn
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 2 weed guides, 10 active-ingredient groups are rated good or excellent for canada thistle in field corn.
| Example product | Active ingredients | MOA group | Ratings checked |
|---|---|---|---|
| Bite EPA 83529-74; same active ingredients on 8 other branded products | clopyralid | 4 | ND Weed Guide 2026: E (PDF) |
| Definite EPA 83529-105; same active ingredients on 7 other branded products | acetochlor, clopyralid, and flumetsulam | 2, 4, 15 | ND Weed Guide 2026: G-E (PDF) |
| COLT AS EPA 34704-1019; same active ingredients on 5 other branded products | clopyralid and fluroxypyr 1-methylheptyl ester | 4 | ND Weed Guide 2026: G-E (PDF) |
| Enlist Duo EPA 62719-649; same active ingredients on 3 other branded products | 2,4-d and glyphosate | 4, 9 | 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 | Ia Weed Guide 2025, ia corn post: G (PDF); ND Weed Guide 2026: G (PDF) |
| Commando EPA 42750-92 | 2,4-d and clopyralid | 4 | 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.
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Sources
Data from current labels and weed guides. Last source update: 2026-07-14.