Orchardgrass

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 orchardgrass. 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 28: inhibits 4hydroxyphenylpyruvatedioxygenase (4-HPPD)

Chemical family (bromoxynil) nitrile; (pyrasulfotole) isoxazole

dimethenamid-P (Outlook)

Rate 0.66 to 0.98 lb ai/A (14 to 21 fl oz/A Outlook)

Time Apply in 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)

Western Oregon only

Rate Established stands 1.6 to 2.4 lb ai/A; new establishments 1.6 lb ai/A or less

Time Apply in fall as rains start weed seed germination. Spray before weeds establish, usually in mid-November.

Remarks Controls annual grasses or broadleaf weeds in new or established stands. A split application more effectively controls annual bluegrass. 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 grass stands planted before April 1 may be treated after October 15. Uniformly spread or bale crop residue before spraying. Use higher rates if considerable crop residue remains in the field. Higher rates 2 years in succession will injure grass. Use a sprayer with mechanical agitation; be careful to avoid spray pattern overlaps. 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

flufenacet + metribuzin (Axiom DF)

Idaho, 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 injure crop and/or poorly control weeds.

Remarks For established grass seed fields only (at least 1 year old, or after first seed harvest). Weed control may be less if excessive straw is on field after harvest. Sufficient 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 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. Crops have been injured at rates of 11 oz/A and above.

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)

Oregon only, west of Cascades and in Crook, Wasco, Deschutes, and Jefferson counties

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 blend of surfactant and crop oil 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 0.125 to 0.375 lb ai/A (8 to 24 oz/A Goal 2XL or Galigan 2E)

Time Apply on established stands in fall and midwinter, before or soon after weeds emerge. Apply first before target grass weed seedlings exceed the two-leaf stage, preferably before December 15. Final applications should be before 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 24 oz/A total during a 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. If tank mixed 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 (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 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

pronamide (Kerb SC)

Oregon only

Rate 0.25 to 0.375 lb ai/A (10 to 15 oz/A Kerb SC)

Time Apply only on established stands that have produced at least one seed crop. Apply during fall and early winter but not after mid-January.

Remarks Apply between November and mid-January after fall rains have moistened soil and soil temperature is 55°F or less. Apply only once; do not exceed 0.375 lb ai/A Kerb in any one growing season. Special local needs label OR-110013.

Caution A restricted-use herbicide. Do not apply to sandy or gravelly areas or to a crop under stress. Do not graze treated fields within 180 days of application. Preharvest interval is 180 days.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Benzamide

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 in a 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

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