Downy Brome

flufenacet + metribuzin (Axiom DF)

Suppression only

Rate 0.136 to 0.34 lb/a flufenacet and 0.034 to 0.085 lb/a metribuzin (4 to 10 oz/a Axiom DF)

Time Apply from wheat germination to the two-leaf growth stage.

Remarks For best results: 1) plant wheat after the first flush of weeds has emerged and is destroyed by tillage; or, in no-till winter wheat, apply a nonselective herbicide to control emerged weeds at or before planting; 2) apply Axiom before the weeds' one-leaf stage; and 3) use the highest specified rate depending on soil texture. Less than 0.5 inch of rainfall or irrigation within two weeks following application may result in reduced weed control.

Caution Winter wheat must be planted at least 1.5 inches deep. Certain wheat varieties are sensitive to Axiom; see label. Do not exceed 10 oz/a Axiom DF per season.

Site of action (flufenacet) Group 15: inhibits very long chain fatty acid synthesis; (metribuzin) Group 5: photosystem II inhibitor

Chemical family (flufenacet) oxyacetamide; (metribuzin) triazine

mesosulfuron (Osprey)

Rate 0.013 lb ai/a (4.75 oz/a Osprey)

Time Apply to winter wheat from wheat emergence to the two-node stage. For downy brome, apply from one-leaf to two-tiller growth stage. See label for application timing and weed size.

Remarks Treat heavy infestations before they compete with the crop. A recommended adjuvant must be tank mixed with Osprey as specified on the label. Do not apply Osprey more than once per crop year.

Caution For winter wheat only.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Sulfonylurea

metribuzin (various trade names)

Suppression only

Rate 0.094 to 0.38 lb ai/a (2 to 8 oz/a of the 75% DF)

Time Apply when wheat is tillering and has developed one-inch secondary roots.

Remarks Plant the seed at least 1.5 inches deep and increase seeding rate by 10%. Do not apply after wheat begins to joint. Follow label regarding soil type and organic matter. Apply metribuzin when the crop is healthy and actively growing. Metribuzin may be applied more than once per crop season. Allow at least 21 days between applications if wheat is actively growing, or allow 45 days between applications if wheat is growing in adverse conditions, has entered dormancy, or is stressed due to frost damage, disease, drought, or excessive moisture. Do not graze treated fields for 14 days after application or harvest grain within 21 days after last application.

Site of action Group 5: photosystem II inhibitor

Chemical family Triazine

metribuzin (various trade names) + chlorsulfuron + metsulfuron (Finesse Cereal and Fallow)

Rate 0.07 to 0.28 lb ai/a metribuzin (1.5 to 6 oz/a of the 75% DF) + 0.23 to 0.3 oz ai/a Finesse Cereal and Fallow (0.3 to 0.4 oz/a Finesse Cereal and Fallow)

Time Apply when wheat is tillering and has developed two-inch secondary roots.

Remarks Plant seed at least 1.5 inches deep and increase the seeding rate by 10%. Do not apply after wheat begins to joint. Follow the label regarding soil type and organic matter. Do not apply more than once per crop. Do not graze treated fields for 14 days after application.

Caution Do not use on soils above pH 7.9. Finesse Cereal and Fallow can persist in soil. Carefully follow label instructions on crop rotations. Many crops may not be planted for 2 years or longer after applying.

Site of action (metribuzin) Group 5: photosystem II inhibitor; (chlorsulfuron and metsulfuron) Group 2: acetolactate synthase (ALS) inhibitor

Chemical family (metribuzin) triazine; (chlorsulfuron and metsulfuron) sulfonylurea

propoxycarbazone (Olympus)

Rate 0.026 to 0.039 lb ai/a (0.6 to 0.9 oz/a Olympus) plus 0.25 to 0.5% nonionic surfactant

Time Apply preplant, preemergence, or postemergence. Preplant and preemergence use limited to 0.6 oz/a rate, which only provides suppression of downy brome. Apply postemergence applications to wheat after the 2-leaf stage begins, but before jointing begins. May be applied in fall or spring, or sequentially. Base application timing on crop stage, not weed stage. Suppression only with spring applications and fall applications of 0.6 oz Olympus/a; control with fall applications of 0.9 oz Olympus/a.

Remarks Do not exceed 1.2 oz/a Olympus per crop year. When applying with fluid fertilizer, spray solution should not be composed of more than 50% liquid nitrogen, and should not exceed 30 lb of actual nitrogen per acre. If applying with liquid nitrogen, use a nonionic surfactant at a maximum of 0.25% v/v.

Caution Do not use with organosilicone-based surfactants.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Sulfonylaminocarbonyltriazolinone

pyroxsulam (PowerFlex HL)

Rate 0.016 lb ai/a (2.0 oz/a PowerFlex HL)

Time Apply in either fall or spring to actively growing winter wheat from the three-leaf to jointing stage and after most weeds have emerged. Apply with a nonionic surfactant (0.25% to 0.50% v/v) and ammonium sulfate (1.5 lb/a).

Remarks When applying with fluid fertilizer, spray solution should not be composed of more than 50% liquid nitrogen, and should not exceed 30 lb of actual nitrogen per acre. If applying with liquid nitrogen, use a nonionic surfactant at a maximum of 0.25% v/v, instead of crop oil concentrate. Suppression only of downy brome with spring applications.

Caution For winter wheat only. Do not mix with products containing dicamba or amine formulations of 2,4-D or MCPA or organophosphate insecticides. Consult label for crop rotation restrictions.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Triazolopyrimidine sulfonamide

sulfosulfuron (Outrider)

Rate 0.031 lb ai/a (0.67 oz/a product) plus 0.5% nonionic surfactant

Time Apply to wheat preplant (supplemental label), preemergence, or up to jointing stage of growth. For best control of brome species, apply fall postemergence when brome is in two- to three-leaf stage. To suppress brome species in spring, apply up to five-tiller growth stage.

Remarks Early spring applications should be when brome has recovered from cold weather, when most foliage is green, not red or purple. Suppression only of downy brome with spring applications.

Caution Do not use within 60 days of crop emergence if an organophosphate insecticide has been applied in-furrow. Do not tank mix with malathion. Do not plant any crop other than wheat for 1 year after application.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Sulfonylurea

triallate (Far-Go or Avadex)

Suppression only

Rate 1.25 to 1.5 lb ai/a (1.25-1.5 quarts/a Far-Go)

Time Apply preplant and incorporate.

Remarks Incorporate lightly in two directions at right angles. Some stand thinning may occur on clay knobs or where wheat is dusted in, due to dry conditions. Do not graze.

Site of action Group 8: lipid synthesis inhibitor but not an ACCase inhibitor

Chemical family Thiocarbamate

trifluralin (Treflan and other trade names)

Rate 0.75 to 1.0 lb ai/a (1.5 to 2.0 pints/a Treflan)

Time Apply after final seedbed preparation any time from three weeks to immediately before planting with a deep-furrow drill, or after planting with a double-disk drill.

Remarks Incorporate within 24 hours after application, using a flextine harrow, in two directions, at right angles. Deep furrow seeding must follow preplant incorporation. Incorporation after planting must be shallow. See label for crop rotation limitations.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline