From labels and weed guides
Group 4 herbicides for horseweed in flax
There are 2 Group 4 active-ingredient groups rated good or excellent for horseweed in flax, with products labeled for flax.
Group 4 mode of action (MOA) options
Group 4 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 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, 2 active-ingredient groups are rated good or excellent for horseweed in flax.
| Example product | Active ingredients | MOA group | Ratings checked |
|---|---|---|---|
| Curtail M EPA 62719-86 | clopyralid and mcpa | 4 | ND Weed Guide 2026: G (PDF) |
| Stinger HL EPA 62719-747 | clopyralid | 4 | ND Weed Guide 2026: G-E (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.