aminopyralid + metsulfuron (Opensight, Chaparral)
Rate 2.5 to 3 oz product/A
Time Apply preemergence in the fall or postemergence in spring to seedlings or rosettes.
Site of action (metsulfuron) Group 2: acetolactate synthase (ALS) inhibitor; (aminopyralid) Group 4: synthetic auxin
Chemical family (metsulfuron) sulfonylurea; (aminopyralid) pyridine
chlorsulfuron (Telar and others)
Rate 0.75 to 0.195 oz ai/A (1 to 2.6 oz/A).
Time Apply in spring to rosettes or to bolting plants with green basal leaves.
Remarks Add 0.25% by volume of nonionic surfactant to spray mixture.
Caution Avoid drift to sensitive crops.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
dicamba (Clarity and others)
Rate 0.75 to 1.5 lb ae/A (1.5 to 3 pints/A)
Time Apply in spring to rosettes or to bolting plants with green basal leaves.
Remarks Dicamba is most effective at higher rates.
Caution Avoid drift to sensitive crops.
Site of action Group 4: synthetic auxin
Chemical family Benzoic acid
glyphosate
Rate 2.25 lb ae/A (3 quarts/A of 3 lb ae/gal product).
Time Apply in spring to rosettes or bolting plants with green basal leaves.
Remarks Add nonionic surfactant if not included in the formulation. Allow at least 7 days after application before tillage.
Caution Glyphosate is nonselective; spray will injure or kill vegetation contacted.
Site of action Group 9: inhibits EPSP synthase
Chemical family None generally accepted.
imazapic (Plateau)
Rate 0.125 to 0.188 lb ae/A (8 to 12 fl oz/A)
Time Apply in spring to rosettes or bolting plants with green basal leaves.
Remarks Add 0.25% by volume of nonionic surfactant or 1.5 to 2 pints/A methylated seed oil or crop oil concentrate to spray mixture.
Caution Avoid drift to sensitive crops.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Imidazolinone
metsulfuron (Escort and others)
Rate 0.6 to 1.2 oz ai/A (1 to 2 oz/A)
Time Apply in spring to rosettes or to bolting plants with green basal leaves.
Remarks Add 0.25% by volume of nonionic surfactant to spray mixture.
Caution Avoid drift to sensitive crops.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea