Rimsulfuron is a sulfonylurea herbicide. Biotypes of kochia, prickly lettuce, and Russian thistle resistant to sulfonylurea herbicides infest Idaho and Washington and will not be controlled by rimsulfuron. Therefore, use resistance-management strategies when using rimsulfuron. A key strategy is to tank-mix rimsulfuron with a herbicide with a different mode of action and is effective on the resistant species. Also, cultural practices such as tillage, preventing weed escapes from going to seed, and good sanitation can help delay development of herbicide-resistant weed populations.  

Common lambsquarters control is better with pre- than with postemergence application, but quackgrass and crabgrass control are better with postemergence application.  

Rimsulfuron is active on hairy nightshade but does not control cutleaf nightshade. When both hairy and cutleaf nightshade infest a field, tank-mix rimsulfuron with EPTC or metolachlor to control both species.  

Rimsulfuron may be applied by ground or through sprinkler irrigation but not by air. When applying preemergence by ground, activate with 0.33 to 1 inch water as soon as possible within 5 days after application.  

When chemigated, apply rimsulfuron in 0.33 to 1 inch/A water (0.33 to 0.5 inch on sandy soils) as a continuous injection in center-pivot and self-propelled wheelmove systems. For hand line and solid-set sprinkler irrigation systems, inject rimsulfuron at the beginning of the set and apply 0.33 to 1 inch water. Research in Idaho shows that when rimsulfuron is chemigated, it controls weeds more consistently when applied preemergence and at the full labeled rate of 0.023 lb ai/A. If rimsulfuron is chemigated after weeds emerge, weeds must be very small (cotyledon to two-leaf stage) in order to achieve acceptable control. 

Do not use on seed potatoes unless permitted by a supplemental label. 

Do not apply within 60 days of harvest.  

Avoid spray drift. Rimsulfuron is very active even at low dosages, and many crops including small grains, canola, sugarbeets, peas, and onions are very sensitive to rimsulfuron drift.  

After application, corn may be planted any time; winter wheat may be planted after 4 months; barley, spring wheat, and spring oats after 9 months except in certain Idaho counties (Teton, Caribou, Madison east of Hwy. 20, and Fremont east of Hwy. 20) where barley may be planted after 12 months; beans (dry and green), sweet corn, sunflowers, and soybeans after 10 months; and sugarbeets after 18 months. See label for details. 

Mixture gives better control of common lambsquarters, Russian thistle, kochia, and wild buckwheat than rimsulfuron alone. The mixture also is an effective resistance- management tool for rimsulfuron-resistant species that are controlled by metribuzin.  

Rimsulfuron + metribuzin controls hairy nightshade but not cutleaf nightshade. When both hairy and cutleaf nightshade infest a field, rimsulfuron + metribuzin must be tank-mixed with EPTC or metolachlor in order to control both species.  

If a split-application strategy is used, (preemergence + postemergence or postemergence + postermergence), do not exceed a total of 0.039 lb ai/A (2.5 oz/A 25% DF) rimsulfuron. Follow recommendations on Lexone or Sencor labels for metribuzin rates to use in split applications. 

Applied postemergence, this mixture may temporarily yellow potato foliage. Under environmental stress (cool, wet weather or hot or humid weather), this mixture applied postemergence also may cause leaf malformations and stunted growth. Potatoes recover within 7 to 10 days. To reduce potential injury, apply mixture only if it has been sunny for at least 3 successive days.  

Do not use on seed potatoes unless permitted by a supplemental label. 

Apply postemergence before June 30. Do not apply within 60 days of harvest.  

Avoid spray drift. Rimsulfuron is very active even at low dosages, and many crops including small grains, canola, sugarbeets, peas, and onions are very sensitive to rimsulfuron drift. Consult product labels for crop rotation restrictions.

Tank-mix provides better control of crabgrass, hairy nightshade, cutleaf nightshade, and common lambsquarters than rimsulfuron alone. A three-way mixture of rimsulfuron + EPTC + metolachlor (Dual), or of rimsulfuron + EPTC + pendi- methalin (Prowl) may be used after planting but before potatoes and weeds emerge.

Do not use on seed potatoes unless permitted by a supplemental label. 

Do not apply within 60 days of harvest.  

Avoid spray drift. Rimsulfuron is very active even at low dosages, and many crops including small grains, canola, sugarbeets, peas, and onions are very sensitive to rimsulfuron drift. Consult product labels for crop rotation restrictions.

Tank-mix provides better control of small-seeded grasses, hairy and cutleaf nightshade, and common lambsquarters than rimsulfuron alone.  

A three-way mixture of rimsulfuron + metolachlor + EPTC (Eptam), or of rimsulfuron + metolachlor + pendimethalin (Prowl) may be used after planting but before potatoes and weeds emerge.

Do not apply within 60 days of harvest.  

Avoid spray drift. Rimsulfuron is very active even at low dosages, and many crops including small grains, canola, sugarbeets, peas, and onions are very sensitive to rimsulfuron drift. Consult product labels for crop rotation restrictions. 

Tank-mix gives better control of kochia (including rimsulfuron-resistant kochia), common lambsquarters, Russian thistle, and crabgrass than rimsulfuron alone.  

Rimsulfuron + pendimethalin controls hairy nightshade but does not control cutleaf nightshade. A three-way mixture of rimsulfuron + pendimethalin + EPTC (Eptam), or of rimsulfuron + pendimethalin + metolachlor (Dual) may be used after planting but before potatoes and weeds emerge. Either three-way mixture would provide better hairy and cutleaf nightshade control than rimsulfuron + pendimethalin.

Do not apply within 60 days of harvest.  

Avoid spray drift. Rimsulfuron is very active even at low dosages, and many crops including small grains, canola, sugarbeets, peas, and onions are very sensitive to rimsulfuron drift. Consult product labels for crop rotation restrictions. 

Three-way mixtures of rimsulfuron + metribuzin + EPTC, or of rimsulfuron + metribuzin + metolachlor, or of rimsulfuron + metribuzin + pendimethalin provide better hairy nightshade control in heavily infested fields than rimsulfuron + metribuzin or rimsulfuron alone. Whether to use EPTC, metolachlor, or pendimethalin in the three-way mix depends on which other weeds infest the field. Consult the table at the end of this section for these herbicides' efficacy on common weed species. 

Use lower rates on coarse, sandy soils, and the higher rate on fine-textured soils.  

When the rimsulfuron + metribuzin + EPTC mix is used postemergence, use  
nonionic surfactant at 0.125% v/v (1 pint/100 gal spray solution).  

Do not use on seed potatoes unless permitted by a supplemental label.  

Avoid spray drift. Rimsulfuron is very active even at low dosages, and many crops  
including small grains, canola, sugarbeets, peas, and onions are very sensitive to  
rimsulfuron drift. Do not apply within 60 days of harvest. Consult product labels for  
crop rotation restrictions.