Note Also see GRASS SEED-New and Established for herbicides that may be used on many species of grass grown for seed.
bromoxynil + pyrasulfotole (Huskie)
Rate 0.185 to 0.205 lb ai/A bromoxynil + 0.033 to 0.036 lb ai/A pyrasulfotole (13.5 to 15 oz/A Huskie)
Time Apply from preemergence to established Kentucky bluegrass. See label for weed size recommendations and application timings, but control of most species is best at the 15 fl oz/A rate when weeds have from one to six leaves. Two applications of Huskie can be made per year separated by at least 30 days.
Remarks For most consistent weed control under adverse growing conditions, add ammonium sulfate or an ammonium nitrogen source as directed by the spray additives section of the label, but do not use these additives if grass crop injury is a concern. Huskie may be tank mixed with a variety of other broadleaf and grass herbicides and other pesticides; see label for instructions.
Caution See label for crop rotation restrictions. Wheat, triticale, and oats may be planted 1 month after application; most other crops may be planted 9 months after application. Do not graze or cut grass for forage within 7 days of application, or cut grass for hay within 30 days of application. Do not exceed 30 oz/A of Huskie per acre per year. Aerial and chemigation applications are prohibited.
Site of action (bromoxynil) Group 6: photosystem II inhibitor; (pyrasulfotole) Group 27: inhibits 4hydroxyphenylpyruvatedioxygenase (4-HPPD)
Chemical family (bromoxynil) Nitrile; (pyrasulfotole) Isoxazole
dicamba (Clarity, several trade names)
Rate 0.25 to 2 lb ae/A
Time Apply before broadleaf weeds have more than two true leaves in fall or late summer. Spray within 10 days after the first fall irrigation or fall rain that will start weed germination.
Remarks Suppresses downy brome (cheatgrass), rattail fescue, and other grassy and broadleaf weeds in bluegrasses. Spray when soil is moist.
Caution Spray on well-established grass stands. Mechanically remove or spread all crop residue before spraying. See specific labels for grazing restrictions.
Site of action Group 4: synthetic auxin
Chemical family Benzoic acid
dimethenamid-P (Outlook, several trade names)
Rate 0.66 to 0.98 lb ai/A (14 to 21 fl oz/A Outlook)
Time Apply to established stands in the fall before targeted weeds emerge, or in a sequential-use program with other herbicides that control emerged weeds. Apply prior to irrigation or activating rainfall for best activity.
Remarks Grass seed crops must be established at least 1 year or have had at least one seed crop harvested before Outlook is applied. Apply higher rates where denser weed infestations are expected. Excessive straw on the field after harvest may reduce weed control. Sufficient rain or irrigation after application is needed for optimum weed control. May be applied by ground or by air (see label).
Caution Do not apply Outlook in tank-mixtures with other herbicides unless risk of crop injury is acceptable. Subsequent applications may injure crop. Do not allow livestock to graze treated fields for 60 days after application. Treated straw, seed, or seed screenings may be fed to livestock after harvest.
Site of action Group 15: inhibits very long chain fatty acid synthesis
Chemical family Chloroacetamide
diuron (Karmex DF, several trade names)
Rate Established stands: 1.6 to 2.4 lb ai/A; new establishments: spring-planted seedling stands: 1.6 lb ai/A or less
Time Apply in fall as rains start weed seed germination. Spray before weed establishment, usually in mid-November.
Remarks Controls annual grasses or broadleaf weeds in new or established stands. Does not control downy brome. Apply 2.4 lb ai/A as early as late October, but before November 15. There are several suppliers of diuron. Check specific labels for crop and geographic restrictions, which can vary considerably between formulations. Allowed for new plantings in conjunction with carbon-banding system.
Caution Well-established, vigorous stands of spring-planted grass may be treated the following fall if the crop is planted before April 1 and treatment is not before October 15. Mechanically remove or spread all crop residue before spraying. Grass is injured when the maximum rate is applied for two consecutive years. Use a sprayer with mechanical agitation; be careful to avoid overlaps in the spray pattern. If application uniformity is poor with desired equipment, spray each field twice at half the desired application rate to prevent skips in application.
Site of action Group 7: photosystem II inhibitor
Chemical family Substituted urea
ethofumesate (Nortron, several trade names)
Rate 1.0 lb ai/A
Time Apply to moist soil surface after fall rains start, or with appropriate irrigation. Apply to annual bluegrass preemergence through three-leaf stage and to rattail fescue, cheatgrass, volunteer wheat and wild oat before the two-leaf stage.
Remarks Controls most annual broadleaf and grass weeds but not annual or perennial ryegrass.
Caution Spray only fields seeded at least 12 months. Mechanically remove or spread all crop residue before spraying. Do not tank mix with other herbicides. Do not graze treated fields. Do not rotate with any crops other than sugarbeets or ryegrass for 12 months after application.
Site of action Group 15: inhibits very long chain fatty acid synthesis
Chemical family Benzofuran
flufenacet + metribuzin (Axiom DF)
Rate 0.3 to 0.4 lb ai/A flufenacet + 0.076 to 0.111 lb ai/A metribuzin (9 to 13 oz/A Axiom)
Time Apply before weeds emerge or no later than the two-leaf stage of volunteer grasses. Applications after mid-November may result in crop injury and/or poor weed control.
Remarks For established grass seed fields only, at least 1 year old or after first seed harvest. Excessive straw on field after harvest may reduce weed control. Rain or irrigation after application is needed for weed control.
Caution Do not apply in tank-mixtures with postemergence herbicides. Applying oxyfluorfen or photosynthesis-inhibiting postemergence herbicides within 4 weeks of Axiom applications may injure crop. Do not allow animals to graze treated fields for a minimum of 30 days following application. Preharvest interval is 120 days. Do not apply more than once per year.
Site of action (flufenacet) Group 15: inhibits very long chain fatty acid synthesis; (metribuzin) Group 5: photosystem II inhibitor
Chemical family (flufenacet) Oxyacetamide; (metribuzin) Triazinone
mesotrione (Callisto, several trade names)
Rate 0.094 to 0.188 lb ai/A (3 to 6 oz/A Callisto)
Time Apply preemergence to bare soil (new seedings) or early postemergence to bluegrass grown for seed. Split applications are allowed, with restrictions.
Remarks Use higher application rates for control and suppression of grass and broadleaf weed species, and for extended soil residual control. The addition of a crop oil concentrate or nonionic surfactant at a rate of 1% v/v is recommended to optimize activity of postemergence applications. In addition, urea ammonium nitrate at 2.5% v/v or ammonium sulfate at a rate of 8.5 lb/100 gal of spray solution may be added, but increases the risk of grass seed crop injury at rates above 3oz/A of Callisto.
Caution Preharvest interval for seed and straw harvest is 60 days. Do not graze or feed forage from treated fields within 14 days after harvest of seed or straw, and at least 74 days after application. Do not exceed two applications or 9 oz/A of Callisto per year. Do not make a second application within 14 days of the first. Do not exceed a total of 0.19 lb ai/a (6 oz/a Callisto) in a single application, or a total of 0.282 lb ai/a (9 oz/a Callisto) per year. Do not tank mix Callisto with other pesticides with EC formulations, because crop injury will result from postemergence applications.
Site of action Group 27: inhibits 4hydroxyphenylpyruvatedioxygenase (4-HPPD)
Chemical family Triketone
metribuzin (Tricor, several trade names)
Washington and in Oregon in all counties west of the Cascades; Oregon east of the Cascades only in Crook, Deschutes, and Jefferson counties.
Rate 0.23 to 0.38 lb ai/A Oregon; 0.15 to 0.3 lb ai/A Washington
Time When volunteer grasses are in the one- to two-leaf stage after fall rain or irrigation but before active spring growth.
Remarks For established grass crops only. Improve control of volunteer crop and grass weeds by adding a blend of surfactant and crop oil at rates recommended on adjuvant label(s). Some crop injury is likely on coarser soils east of the Cascades
Caution Preharvest interval is 28 days for grazing, 120 days for seed harvest. See additional cautions on individual labels.
Site of action Group 5: photosystem II inhibitor
Chemical family Triazinone
oxyfluorfen (Goal 2XL or Galigan 2E)
Goal 2XL in Idaho, Oregon, and Washington; Galigan 2E in Oregon and Washington only
Rate 0.125 to 0.375 lb ai/A (8 to 24 oz/A Goal 2XL or Galigan 2E)
Time Apply on established stands during fall (both sides of Cascades) or midwinter (west of Cascades). Apply before or soon after weeds emerge. Apply before grass weed seedlings to be controlled exceed the two-leaf stage. In eastern Oregon, apply prior to onset of full winter dormancy in late November. In western Oregon, applications before December 15 are preferred, and make final applications no later than mid- January.
Remarks Apply to established fields with at least six tillers per plant. Fields may be treated more than once, but do not exceed 0.375 lb ai/a (24 oz/A Goal) total in a crop season. Goal and Galigan 2E labels vary by state. Goal and Galigan SLN labels vary by state. Special local needs labels OR-990006B and WA-020027 (Goal) and OR-010028 and WA-010037 (Galigan).
Caution May discolor crop foliage significantly. Leaf chlorosis and reduced vegetative growth are typical plant responses. If using a tank-mix with diuron, do not exceed 1.2 lb ai/A diuron per season. Review the specific oxyfluorfen label you are using for updated preharvest and grazing restrictions, which may be up to 6 to 12 months.
Site of action Group 14: protoporphyrinogen oxidase (PPO) inhibitor
Chemical family Diphenylether
pendimethalin (Prowl H2O, several trade names)
Rate 2 to 4 lb ai/a (2.1 to 4.2 quarts/a/a Prowl H2O)
Time Apply at the beginning of significant fall rains and before weeds germinate. Treatments are most effective with adequate rain or overhead irrigation within 7 days after application.
Remarks For established grass fields only (six or more tillers). Prowl will not control established weeds. See label for specifics on tank-mixes with other herbicides. Removing excessive straw and crop residues may increase effectiveness. Fall applications made to perennial grasses which exceed 6 inches in height may result in reduced weed control due to reduced spray coverage to bare soil.
Caution May temporarily injure grass stands. Tank-mixtures and applications in extreme weather and to weak stands may increase crop injury. Do not harvest forage from treated fields within 45 days of application or harvest hay from treated fields within 60 days of application. The PHI for seed production is 90 days and grass seed screenings may not be used in livestock feed. Grass seed straw from treated fields may be fed to livestock and treated fields may be grazed after harvest. Refer to main labels for crop rotation restrictions.
Site of action Group 3: microtubule assembly inhibitor
Chemical family Dinitroaniline
primisulfuron-methyl (Beacon)
Oregon and Washington only
Rate 0.0356 lb ai/A (0.76 oz/A Beacon)
Time Apply to recently emerged, actively growing weeds no larger than the size listed on the label. The Kentucky bluegrass crop should be growing vigorously under favorable conditions at application time. Avoid applications when low temperatures will fall below 29 F for 3 days before and after application.
Remarks Apply postemergence to seedling and established stands of Kentucky bluegrass that have at least one tiller (4-5 leaves) but before jointing. Applications can be split into two applications of 0.38 oz/A each, but do not exceed 0.76 oz/A. Beacon during one crop season. Special local needs labels OR-960025 and WA-960002. Visit farmassist.com/Labels/IndemnifiedLabels.aspx to obtain label and indemnification agreement. Primisulfuron-methyl not currently available in retail market.
Caution Applications may injure Kentucky bluegrass crop, particularly during times of crop stress or freezing temperatures. Take special care in cleaning spray equipment; read label for directions. Do not apply to bluegrass under stress. Do not irrigate within 4 hr of application. Do not graze or use forage from treated fields until after harvest. Straw and screenings from harvested fields may be fed to livestock. Do not graze within 90 days of application. Preharvest interval is 60 days.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
primisulfuron-methyl + dicamba (NorthStar)
Oregon only
Rate 0.023 lb ai/a primisulfuron-methyl + 0.125 lb ae/ac dicamba (5 oz/a NorthStar)
Time Apply to recently emerged, actively growing weeds no larger than the size listed on the label. The Kentucky bluegrass crop should be growing vigorously under favorable conditions at application. Avoid applications when low temperatures will fall below 29 F for 3 days before and after application.
Remarks Apply postemergence to seedling stands of Kentucky bluegrass that have at least one tiller (4-5 leaves) but before jointing in the year of establishment only. A crop oil concentrate is recommended for applications of NorthStar alone. Tank mixing with other herbicides is not recommended. Applications can be split into two applications of 0.38 oz/a each, but do not exceed 0.76 oz/a Beacon during one crop season. Special local needs labels OR-190013. Primisulfuron-methyl not currently available in retail market.
Caution Applications may injure Kentucky bluegrass crop, particularly during times of crop stress or freezing temperatures. Take special care in cleaning spray equipment; read label for directions. Do not apply to bluegrass under stress. Do not irrigate within 4 hours of application. Do not graze or use forage from treated fields until after harvest. Straw and screenings from harvested fields may be fed to livestock. Do not graze within 90 days of application. Preharvest interval is 60 days. Do not apply in tank mixture with, nor within 10 days before or after application of any organophosphate insecticide. Do not exceed a total of 7.6oz/a NorthStar during one crop season.
Site of action (primisulfuron-methyl) Group 2: acetolactate synthase (ALS) inhibitor, (dicamba) Group 4: synthetic auxin
Chemical family (primisulfuron-methyl) Sulfonylurea, (dicamba) Benzoic Acid
S-metolachlor (Dual II Magnum, several trade names)
Rate 0.95 to 1.27 lb ai/A
Time Apply to established stands just before, during, or immediately after the first fall rains or an irrigation. Treat target weeds before they emerge.
Remarks Apply only to stands harvested for seed at least once, or planted at least 1 year before treatment. Rain or irrigation is required after application and before weeds emerge for best weed control.
Caution Apply only once per crop season. Do not apply after November 15. Tank-mixtures with postemergence herbicides may injure crop. See specific labels for grazing and feeding restrictions based on geography.
Site of action Group 15: inhibits very long chain fatty acid synthesis
Chemical family Chloroacetamide
terbacil (Sinbar WDG)
Rate 0.4 to 0.8 lb ai/A (0.5 to 1 lb/A Sinbar WDG)
Time Spray before weed establishment after fall rains start weed germination, usually mid-November. One inch of rain or irrigation is needed after application for good control.
Remarks To control annual grasses or broadleaf weeds in established bluegrass fields. Rotation restrictions may be up to 2 years
Caution Mechanically remove or spread all crop residue before spraying. Apply only to well-established fields that have been harvested at least once for seed. Soil residues may persist for 2 years. Do not graze treated fields. May cause crop injury when crop is under stress caused by weather, insects, or disease. See label for soil type restrictions.
Site of action Group 5: photosystem II inhibitor.
Chemical family Uracil