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 tall fescue. 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
chlorsulfuron (Glean XP)
Rate 0.012 lb ai/A (0.25 oz/A Glean XP)
Time Apply to broadleaf weeds, including wild carrot, in tall fescue grown for seed in late summer or early fall after seed harvest.
Remarks Apply with NIS to maximize weed control efficacy and apply with 0.5 to 1.0 lb ai/A of 2,4-D to improve crop safety. Apply when the tall fescue has less than 6 inches of regrowth.
Caution Applications to tall fescue may cause crop injury including reduced crop height and reduced seed yield, particularly if applications are delayed until late fall or spring and made when the tall fescue is actively growing. There are no grazing restrictions following applications of Glean XP. See Glean XP label for crop rotation restrictions.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
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)
Rate Established stands: 1.6 to 2.4 lb ai/A. New establishments: 1.6 lb ai/A or less
Time Apply in the fall as rains start the germination of weed seeds. Spray before weeds establish, usually in mid-November.
Remarks Controls annual grasses or broadleaf weeds in new or established stands. Apply 2.4 lb ai/A in late October and before November 15. There are several suppliers of diuron. Check labels for crop and geographical restrictions.
Caution Well-established, vigorous stands of spring-planted grass (new establishments) may be treated the next fall if the crop is planted before April 1 and diuron is not applied before October 15. Mechanically spread unbaled crop residue uniformly before spraying. Higher application rates 2 years in succession will damage grass. Use a sprayer with mechanical agitation; avoid overlaps in the spray pattern. Spray each field twice at half theesired application rate to prevent skips in application.
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 within36 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
ethofumesate (several trade names)
Western Oregon and Washington only
Rate 0.75 to 1.9 lb ai/A (1.5 to 3.75 pints/A product)
Time Apply early postemergence of crop (two leaves) to control rattail fescue, volunteer wheat and wild oats, but no later than the four-leaf stage of weeds.
Remarks To control annual bluegrass, rattail fescue, volunteer cereals, wild oat, and other winter annuals. Use higher application rate on emerged weeds including rattail fescue and volunteer wheat. Carbon-banded fields need 2 inches or more of rain to dissipate the carbon band before application. Ethofumesate is most effective when applied to a firm seedbed free of crop residue. Soil surface should be moist at the time of application. Rain or sprinkler irrigation should follow soon after application to increase herbicide effectiveness.
Caution Do not graze treated fields. Do not rotate with any crops other than sugar beet or ryegrass for 12 months after application.
Site of action Group 16: unknown
Chemical family Benzofuran
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). Excessive straw on field may reduce weed control. Rain or irrigation after application is needed for sufficient weed control.
Caution Do not apply in tank-mixtures with postemergence herbicides. Applying oxyfluorfen or photosynthesis-inhibiting postemergence herbicides within 4 weeks of Axiom 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
indaziflam (Alion Herbicide)
Rate 0.025 to 0.0375 lb ai/A (2.0 to 3.0 oz/A of Alion)
Time Apply to dry soil in established grass seed fields prior to any weed emergence before rain or irrigation.
Remarks For established tall fescue seed fields.
Caution See Alion label for use precautions and use restrictions. Use the 3.0 oz rate only east of the Cascades. Use Alion only once (either at carbon-planting or once in an established stand) to minimize risk of herbicide carryover to subsequent rotational crops i.e., do not apply to established fields if Alion was used during the establishment phase (carbon-seeding) of the stand or apply late in the predicted life of the grass seed stand.
Site of action Group 29: inhibition of cellulose biosynthesis
Chemical family Fluoroalkyl triazine
mesotrione (Callisto)
Rate 0.094 to 0.188 lb ai/A (3 to 6 oz/A Callisto)
Time Apply preemergence to bare soil or early postemergence to tall fescue grown for seed.
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 3 oz/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 tank mix Callisto with other pesticides with EC formulations or crop injury will result from postemergence applications.
Site of action Group 27: inhibits 4hydroxyphenylpyruvatedioxygenase (4-HPPD)
Chemical family Triketone
metribuzin (several trade names)
Oregon west of the Cascades and in Crook, Deschutes, Jefferson, and Wasco counties, and Washington only
Rate 0.25 to 0.56 lb ai/A Oregon; 0.25 to 0.38 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 Established grass crops only. Improve volunteer crop and grass weed control by adding a surfactant or crop oil blend at rates recommended on the wetting agent label. Up to 3 applications may be made to tall fescue, but do not apply more than 0.56 lb ai/A per year.
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 only
Rate 0.03 to 0.046 lb ai/A (2 to 3 oz/A Goal 2XL or Galigan 2E)
Time Apply on new plantings that have at least one tiller or more per plant. Applications to plants with less than one tiller may result in severe crop injury or stand loss. For best results, apply at early postemergence to the target annual broadleaf weeds.
Remarks Oxyfluorfen may be applied alone or in a tank-mix with up to 3 pints/A of ethofumesate. Crop may be discolored temporarily and, when tank mixed with ethofumesate, crop injury may increase. Goal and Galigan SLN labels vary by state.
Caution Application of oxyfluorfen in a tank-mix with ethofumesate is at the sole discretion of the grower and at the grower's own risk. Do not apply to a crop that is under stress, because additional crop injury may occur. Review the specific oxyfluorfen SLN label you are using for updated preharvest and grazing restrictions.
Site of action Group 14: protoporphyrinogen oxidase (PPO) inhibitor
Chemical family Diphenylether
oxyfluorfen (Goal 2XL or Galigan 2E)
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 during fall and midwinter, before or soon after weeds emerge. Apply first before weeds (grass) seedlings to be controlled exceed the two-leaf stage, preferably before December 15. Make final applications before mid-January.
Remarks Apply to established fields that have at least six tillers per plant. Fields may be treated more than once but with no more than a total of 24 oz/A during a crop season. Goal and Galigan SLN labels vary by state.
Caution Oxyfluorfen applications might substantially discolor crop foliage. Leaf chlorosis and reduced vegetative growth are typical plant responses to oxyfluorfen treatments. If using a tank-mix with diuron, do not exceed 1.2 lb ai/A diuron in a season. Review the specific oxyfluorfen SLN label you are using for updated preharvest and grazing restrictions.
Site of action Group 14: protoporphyrinogen oxidase 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 (Zidua SC Herbicide)
West of Cascades in Oregon and Washington only
Rate 0.098 lb ai/A of pyroxasulfone (3.0 oz/A of Zidua SC)
Time Apply before weeds emerge in established tall fescue fields.
Remarks For established tall fescue seed fields west of the cascades. 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 Zidua SC label for use precautions and use restrictions. Use Zidua SC only once during the growing season.
Site of action Group 15: inhibits very long chain fatty acid synthesis
Chemical family Isoxazoline
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
S-metolachlor (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 Apply in fall or early winter when temperatures are cool and grass is not actively growing.
Remarks For established grass seed fields only. Results are best if straw is removed by baling. A heavy layer of straw reduces weed control. Weed control improves if applied after rain has wetted the soil; rain after application moves herbicide into the root zone, increasing effectiveness. See label for soil type restrictions.
Caution Apply to established fields that have had at least one seed crop. Do not plant treated fields to another crop within 2 years of application. Do not graze treated fields or feed hay products before seed harvest. Preharvest interval is 90 days. Straw and seed screenings may be fed to livestock.
Site of action Group 5: photosystem II inhibitor
Chemical family Uracil