From labels and weed guides
Group 15 herbicides for canada thistle in corn silage
There are 2 Group 15 active-ingredient groups rated good or excellent for canada thistle in corn silage, with products labeled for corn silage.
Group 15 mode of action (MOA) options
Group 15 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 corn silage. 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 canada thistle in corn silage.
| Example product | Active ingredients | MOA group | Ratings checked |
|---|---|---|---|
| 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) |
| 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) |
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.