From labels and weed guides
Best herbicides for knotweed in barley
For knotweed in barley, the weed guides list 4 active-ingredient groups with every rating at least 80% control, after checking that the products are labeled for barley.
Knotweed control in barley
Every listed product is labeled for barley. Ratings are shown when each weed guide that rates this weed has a lower interval bound of at least 80% control for the active-ingredient group. If a guide gives a range, its lower bound must be at least 80%.
Based on 1 weed guide, 4 active-ingredient groups are rated at least 80% control for knotweed in barley.
| Example product | Active ingredients | MOA group | Ratings checked |
|---|---|---|---|
| Bison EPA 71368-28-1381; same active ingredients on 11 other branded products | bromoxynil and mcpa | 4, 6 | WinField Crop Protection 2026, small grains: E → 91–100% control (PDF) |
| Carnivore EPA 1381-249; same active ingredients on 2 other branded products | bromoxynil, fluroxypyr 1-methylheptyl ester, and mcpa | 4, 6 | WinField Crop Protection 2026, small grains: G/E → 81–100% control (PDF) |
| Agility SG EPA 352-751 | dicamba, metsulfuron-methyl, thifensulfuron, and tribenuron-methyl | 2, 4 | WinField Crop Protection 2026, small grains: G → 81–90% control (PDF) |
| Quelex EPA 62719-661 | florasulam and halauxifen-methyl | 2, 4 | WinField Crop Protection 2026, small grains: G → 81–90% control (PDF) |
Rating bands: E 90-100%, G 80-89%, F 70-79%, P under 70%, N none. Policy intervals are marked in the source ratings. 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. Read the rating method.
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Sources
Data from current labels and weed guides. Last source update: 2026-09-30.