2,4-D
Rate 0.95 to 1.9 lb ae/A (2 to 4 pints/A)
Time Apply to seedlings in spring when plants are growing rapidly.
Remarks Good coverage is necessary to achieve control.
Caution Do not drift to sensitive crops.
Site of action Group 4 synthetic auxin
Chemical family Phenoxy acetic acid
aminopyralid (Milestone)
Rate 0.75 to 1.25 oz ae/A (3 to 5 fl oz/A)
Time Apply to seedlings in spring when plants are actively growing.
Remarks Manure management of grazing animals may be necessary depending on the site; see label for details.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
clopyralid (Transline)
Rate 1.5 to 3.75 oz ae/A (4 to 10 fl oz/A).
Time Apply to seedlings in spring when plants are actively growing.
Caution Do not contaminate water. Potatoes, beans, and many other crops are very sensitive to clopyralid. Do not use in diversified cropping areas.
Site of action Group 4 synthetic auxin
Chemical family Pyridine
dicamba (Clarity and others)
Rate 0.25 to 0.75 lb ae/A (0.5 to 1.5 pints/A)
Time Apply to seedlings in spring when plants are actively growing.
Caution Avoid drift to sensitive crops.
Site of action Group 4: synthetic auxin
Chemical family Benzoic acid
fluroxypyr (Vista)
Rate 3.4 oz ae/A (11 oz/A)
Time Apply to seedlings in spring when plants are actively growing.
Caution Avoid drift to sensitive crops.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
glyphosate
Rate 1.1 to 2.25 lb ae/A.
Time Apply to seedlings in spring when plants are actively growing.
Remarks Adequate foliar coverage of cocklebur is necessary. Add nonionic surfactant if not included in the formulation.
Caution Glyphosate is nonselective and injures or kills other vegetation in the treated area.
Site of action Group 9: inhibits EPSP synthase
Chemical family None generally accepted
imazapic (Plateau)
Rate 1 to 1.5 oz ae/A (4 to 6 fl oz/A)
Time Apply preemergence or postemergence to actively growing cockleburs.
Remarks Add 0.25% by volume of nonionic surfactant, or 1.5 to 2 pints/A methylated seed soil or crop oil concentrate to spray mixture.
Caution Some grass species are sensitive to imazapic; see label for details.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Imidazolinone
imazapyr (Arsenal, Habitat)
Rate 0.75 to 1 lb ae/A (3 to 4 pints/A)
Time Apply preemergence or postemergence to actively growing cockleburs.
Remarks Add 0.25% by volume of nonionic surfactant, or 1 to 2 pints/A methylated seed soil or crop oil concentrate to spray mixture.
Caution Imazapyr is nonselective; spray will injure or kill vegetation contacted.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Imidazolinone
metsulfuron (Escort and others)
Rate 0.2 to 0.3 oz ai/A (0.33 to 0.5 oz/A)
Time Apply to seedlings in spring when plants are actively growing.
Remarks Add 0.25% by volume of nonionic surfactant to spray mixture. Application sites differ between products; consult labels.
Caution Avoid contacting sensitive crops. Apply only to pasture, rangeland, and non-crop sites.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
picloram (Tordon)
Rate 4 to 8 fl oz ae/A
Time Apply to seedlings in spring when plants are actively growing.
Caution Most formulations are restricted-use herbicides. See label for grazing restrictions. Do not contaminate water. Potatoes, beans, and many other crops are very sensitive to picloram. Do not use in diversified cropping areas. At rates above 0.5 lb ae/A (1 quart/A), apply only as spot treatment not to exceed 25% of a landowner's acreage in a given watershed in a single season.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
sulfosulfuron (Outrider)
Rate 0.56 to 1 oz ai/A (0.75 to 1.33 oz/A)
Time Apply to seedlings in spring when plants are actively growing.
Remarks Add 0.25% by volume of nonionic surfactant to spray mixture.
Caution Avoid contacting sensitive crops.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
triclopyr (Garlon 3A or 4)
Rate 1 lb ae/A.
Time Apply to seedlings in spring when plants are actively growing.
Caution Garlon 4 is an ester formulation; do not drift onto sensitive crops. Do not contaminate water.
Site of action Group 4 synthetic auxin
Chemical family Pyridine