From labels and weed guides
Best herbicides for knotweed in barley
For knotweed in barley, the weed guides list 4 active-ingredient groups rated good or excellent, 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 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, 4 active-ingredient groups are rated good or excellent 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 (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 (PDF) |
| Agility SG EPA 352-751 | dicamba, metsulfuron-methyl, thifensulfuron, and tribenuron-methyl | 2, 4 | WinField Crop Protection 2026, small grains: G (PDF) |
| Quelex EPA 62719-661 | florasulam and halauxifen-methyl | 2, 4 | WinField Crop Protection 2026, small grains: 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.