From labels and weed guides

Best herbicides for purple ammannia (redstem) in rice

For purple ammannia (redstem) in rice, the weed guides list 2 active-ingredient groups rated good or excellent, after checking that the products are labeled for rice.

Purple Ammannia (redstem) control in rice

Every listed product is labeled for rice. 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 purple ammannia (redstem) in rice.

Example productActive ingredientsMOA groupRatings checked
Gambit
EPA 81880-27-10163
halosulfuron-methyl and prosulfuron2Ms Weed Guide 2025, ms rice pre: G (PDF)
League
EPA 59639-166
imazosulfuron2Ms Weed Guide 2025, ms rice pre: 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.