chlorsulfuron (Telar)
Idaho and Washington only
Rate 1.5 to 2.25 oz ai/A (2 to 3 oz/A Telar)
Time Apply to actively growing yellow toadflax in the bud to bloom stage.
Remarks Suppresses yellow toadflax. Selective to grasses. Use a penetrating surfactant. Spray to wet.
Caution Do not let spray drift onto sensitive crops. Apply only to non-cropland.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
dicamba (Clarity)
Rate 4 to 6 lb ae/A
Time Apply in early spring before toadflax reaches bloom stage.
Remarks Repeated applications may be necessary for complete control.
Caution Avoid drift to sensitive crops. Dicamba severely injures or kills most broadleaf plants.
Site of action Group 4: synthetic auxin
Chemical family Benzoic acid
imazapic (Plateau)
Rate 0.188 lb ai/A
Time Apply in the fall when top 25% of plant is necrotic, usually after a hard frost.
Remarks Add 1 quart/A methylated seed oil to the spray mix.
Caution Before using, note crop rotation restrictions.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Imidazolinone
picloram (Tordon)
Rate 1 lb ae/A
Time Apply to actively growing toadflax in spring before full bloom or in late summer or fall.
Remarks A selective treatment that will not damage perennial grasses at the suggested rate.
Caution Most formulations are restricted-use herbicides. Do not contaminate water. Do not use in diversified crop areas. Potatoes, beans, and most other broadleaf crops are sensitive to picloram. This rate for spot treatment only.
Site of action Group 4: synthetic auxin
Chemical family Pyridine
picloram (Tordon 22K) + 2,4-D
Rate 0.5 lb ae/A picloram + 1.5 lb ae/A 2,4-D
Time In spring before full bloom.
Remarks May require annual treatment for 2 to 3 years. This rate of Tordon 22K may be broadcast.
Caution Tordon is a restricted-use herbicide. See label for grazing restrictions. If rate exceeds 0.5 lb ae/A (1 quart/A), apply only as a spot treatment not to exceed 25% of a landowner's acreage in any particular watershed in a single season. Avoid drift to sensitive crops. Do not contaminate water. Potatoes, beans, and many other broadleaf crops are sensitive to these herbicides. Do not use picloram in diversified crop areas.
Site of action (both) Group 4: synthetic auxin
Chemical family (picloram) pyridine; (2,4-D) phenoxy acetic acid