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 fine fescues. 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 AMS 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 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 (several trade names)
Rate 0.25 to 1 lb ai/A
Time Apply before broadleaf weeds have more than two leaves in summer or fall. Spray within 10 days after the first fall irrigation or rain starts weed germination.
Remarks Suppresses downy brome (cheatgrass), rattail fescue, and other grassy and broadleaf weeds in creeping red and Chewings fescue. Spray when soil is moist. The maximum use rate per season is 2 lb ai/A.
Caution Spray on well-established stands of grass. Uniformly burn fields, and mechanically spread unburned residues before spraying. See specific labels for grazing restrictions.
Site of action Group 4: synthetic auxin
Chemical family Benzoic acid
dimethenamid-P (Outlook)
Rate 0.66 to 0.98 lb ai/A (14 to 21 fl oz/A Outlook)
Time Apply in the fall before targeted weeds emerge or in midwinter in a sequential-use program with other herbicides that control emerged weeds.
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 following harvest.
Site of action Group 15: inhibits very long chain fatty acid synthesis
Chemical family Chloroacetamide
diuron (several trade names)
Washington and Oregon only
Rate 0.8 to 1.6 lb ai/A (1 to 2 lb/A of an 80DF formulation)
Time At the onset of fall rains and before weeds are beyond the two- to four-leaf stage.
Remarks Apply only to well-established, vigorous stands of grass. Refer to label for specific directions.
Caution Apply only once a year. Do not use diuron more than 2 year in a row on the same field.
Site of action Group 7: photosystem II inhibitor
Chemical family Substituted urea
EPTC ( Eptam 7 EC Selective Herbicide)
Rate 3.01 to 4.38 lb ai/A (3.5 to 5.0 pints/A of Eptam)
Time Apply to dry soil in established grass seed fields prior to any weed emergence immediately before rain or irrigation to minimize losses to volatilization.
Remarks Rainfall or irrigation in the amount of 0.25 to 0.5 inches within 36 hr of application is needed to activate the herbicide.
Caution See Eptam label for use precautions and use restrictions. Use Eptam only once during the growing season.
Site of action Group 8: inhibitor of lipid synthesis; not ACCase inhibition
Chemical family Thiocarbamate
fluazifop (Fusilade DX)
Rate 0.125 to 0.25 lb ai/A (0.5 to 1 pint/A Fusilade DX)
Time Apply to actively growing grasses, 2 to 4 inches tall; normally, this is in November. Early spring timing normally is March.
Remarks Controls grasses in creeping red, Chewings, and hard fescue varieties; does not control broadleaf weeds or sedges. The lower rate normally controls grasses 2 to 4 inches tall, but larger, established grasses (4 to 6 inches) may need higher rate for control. Established quackgrass and bentgrass require the higher rate and may need a second application for adequate control. A total of 0.5 lb ai/A may be applied per season but no more than 0.25 lb ai/A at one time. Special local needs labels OR-950013, ID-040003, and WA-040024.
Caution Do not apply after boot stage. Do not graze treated fields. Use a crop oil concentrate or nonionic surfactant for adequate weed control. Tall fescue does not tolerate fluazifop.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Aryloxyphenoxy propionate
flufenacet + metribuzin (Axiom DF)
Idaho and Washington, and Oregon, except for Jefferson County
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). Weed control may be reduced if excessive straw remains on field after harvest. Rain or irrigation after application is needed for good 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
metribuzin (several trade names)
Western Oregon and Crook, Deschutes, Jefferson, and Wasco counties; and Washington only
Rate 0.25 to 0.38 lb ai/A
Time When volunteer grasses are in the one- to two-leaf stage after fall rain or irrigation but before active spring growth.
Remarks Established grass crops only. Improve volunteer crop and grass weed control by adding a surfactant/crop oil blend at rates recommended on the wetting agent label.
Caution Allow at least 28 days after application before grazing. Preharvest interval is 120 days. See additional cautions on individual labels.
Site of action Group 5: photosystem II inhibitor
Chemical family Triazinone
oxyfluorfen (Goal 2XL or Galigan 2E)
Oregon and Washington only
Rate 0.12 lb ai/A (8 oz/A Goal 2XL or Galigan 2E)
Time Apply on established stands in fall and early winter (September 1 to December 15), before or soon after weeds emerge. Make a single application before weed (grass) seedlings to be controlled exceed the two-leaf stage.
Remarks Apply to established fields with at least six tillers. Apply only once per crop season. Goal and Galigan SLN labels vary by state.
Caution Applications may substantially discolor crop foliage; leaf chlorosis and reduced vegetative growth are typical plant responses. Review the specific oxyfluorfen SLN you are using for updated preharvest and grazing restrictions.
Site of action Group 14: protoporphyrinogen oxidase (PPO) inhibitor
Chemical family Diphenylether
pendimethalin (Prowl H2O)
Rate 2 to 3 lb ai/A (4.2 to 6.3 pints/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 that 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
pyroxasulfone + flumioxazin ( Fierce EZ Herbicide)
Rate 0.032 to 0.064 lb ai/A of flumioxazin + 0.040 to 0.080 lb ai/A of pyroxasulfone (3.0 to 6.0 oz/A of Fierce EZ)
Time Apply before weeds emerge, or no later than the two-leaf stage of volunteer grasses in established perennial ryegrass fields.
Remarks Rainfall or irrigation in the amount of 0.5 inches within 7 to 14 days of application is needed to activate the herbicide.
Caution See Fierce EZ label for use precautions and use restrictions. Use Fierce EZ only once during the growing season.
Site of action (flumioxazin) Group 14: protoporphyrinogen oxidase (PPO) inhibitor, (pyroxasulfone) Group 15: inhibits very long chain fatty acid synthesis.
Chemical family (flumioxazin) Dicarboximide; (pyroxasulfone) Isoxazoline
sethoxydim (Poast)
Oregon only
Rate 0.28 to 0.47 lb ai/A (1.5 to 2.5 pints/A Poast)
Time Apply when fine fescue is semi-dormant (generally November 1 through March 15).
Remarks To control annual ryegrass, downy brome, German velvetgrass, and colonial and highland bentgrass. Poast does not control broadleaf weeds, sedges, annual bluegrass, or rattail fescue and will injure tall fescue.
Caution Do not feed treated grasses, forage, hay, silage, straw, seed, or seed screenings to livestock.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Cyclohexanedione
S-metolachlor (several trade names)
Rate 0.95 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 during a crop season. Application may injure a crop under stress. 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 Apply in the fall 4 to 6 weeks after burning fields, and after 2 inches of rain or irrigation to allow ash to disperse.
Remarks Controls downy brome (cheatgrass), rattail fescue, and other grassy and broadleaf weeds in creeping red and Chewings fescue.
Caution One inch of moisture is required within 2 weeks after application for satisfactory weed control. Apply only to well-established fields harvested at least once for seed. Herbicide residues remain in soil up to 2 years. Do not graze treated fields. May injure crops stressed by weather, insects, or disease. See label for soil type restrictions.
Site of action Group 5: photosystem II inhibitor
Chemical family Uracil