From labels and weed guides
Best herbicides for russian thistle in flax
For russian thistle in flax, the weed guides list 5 active-ingredient groups rated good or excellent, after checking that the products are labeled for flax.
Russian Thistle control in flax
Every listed product is labeled for flax. 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, 5 active-ingredient groups are rated good or excellent for russian thistle in flax.
| Example product | Active ingredients | MOA group | Ratings checked |
|---|---|---|---|
| Antares EPA 82534-5-5905; same active ingredients on 17 other branded products | sulfentrazone | 14 | ND Weed Guide 2026: G-E (PDF) |
| Bison EPA 71368-28-1381; same active ingredients on 11 other branded products | bromoxynil and mcpa | 4, 6 | ND Weed Guide 2026: E (PDF) |
| Broclean EPA 34704-891; same active ingredients on 5 other branded products | bromoxynil | 6 | ND Weed Guide 2026: E (PDF) |
| Maxunitech Carfentrazone + Sulfentrazone SE EPA 95009-3; same active ingredients on 1 other branded product | carfentrazone-ethyl and sulfentrazone | 14 | ND Weed Guide 2026: G-E (PDF) |
| Curtail M EPA 62719-86 | clopyralid and mcpa | 4 | 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.