Thistle, Italian (Carduus pycnocephalus), slenderflower (Carduus tenuiflorus) , and plumeless (Carduus acanthoides)

clopyralid (Transline or Stinger)

Rate 0.125 to 0.25 lb ae/a (0.33 to 0.66 pint/a)

Time Apply to rosettes

Remarks Consult labels for specific site registrations.

Caution Product will injure or kill sensitive broadleaf forages. Consult label for crop rotation restrictions before using. Several crops may be injured several years after application.

Site of action Group 4: synthetic auxin

Chemical family Pyridine

MCPA amine

Rate 1.5 lb ae/a

Time When thistle is actively growing but before bolting. Thistle rosettes wider than 6 inches may be difficult to control.

Remarks Subclover smaller than two trifoliate leaves may be severely injured by this treatment. Other formulations may injure clover more severely. Aerial applications often produce erratic results. Results are good from applications in October through early April, but thistles may be too dormant in midwinter in some years.

Caution Avoid drift to sensitive crops.

Site of action Group 4: synthetic auxin

Chemical family Phenoxy acetic acid