Houndstongue (Cynoglossum officinale)

2,4-D LV ester

Rate 2 lb ae/a

Time Early spring to actively growing plants before they bloom.

Remarks Sticky seeds can contaminate wool. Mowing before seed production helps alleviate wool contamination.

Caution Avoid drift to sensitive crops.

Site of action Group 4: synthetic auxin

Chemical family Phenoxy acetic acid

aminocyclopyrachlor + chlorsulfuron (Perspective)

Rate 1.8 to 3.2 oz/a aminocyclopyrachlor + 0.7 to 1.3 oz/a chlorsulfuron (4.5 to 8 oz/a of product)

Time Apply to actively growing plants in spring.

Remarks Adjuvants can be used; these include methylated seed oils 0.5 to 1% v/v, nonionic surfactants at 0.25 to 1% v/v, and crop oil concentrates at 1% v/v. Can be applied using an invert emulsion rather than water.

Caution Even low rates can kill nontarget tree and shrub species so avoid application within a distance equal to the tree height of the sensitive species. Do not allow spray to drift off target. Can injure several grass species including bromes, as well as basin wildrye.

Site of action (aminocyclopyrachlor) Group 4: synthetic auxin; (chlorsulfuron) Group 2: ALS inhibitor

Chemical family (aminocyclopyrachlor) Pyrimidine carboxylic acid; (chlorsulfuron) Sulfonylurea

imazapic (Plateau)

Rate 0.125 to 0.188 lb/a

Time Apply to actively growing plants.

Remarks Use lower rates if rosettes are small; increase rate if rosettes are large or bolting. Selective to most native grasses. Higher rates may suppress seed of some cool-season grasses.

Caution Before using, note crop rotation restrictions.

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

Chemical family Imidazolinone

metsulfuron (Escort and others)

Rate Escort: 0.6 oz ai/a (1 oz/a)

Time Any time plants are growing well.

Remarks Application sites differ between products; see labels.

Caution Apply only to pasture, rangeland, and non-crop sites.

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

Chemical family Sulfonylurea

picloram (Tordon)

Rate 0.5 lb ae/a

Time Any time plants are growing well.

Remarks Reported to give fair to good control.

Caution Most formulations are restricted-use herbicides.

Site of action Group 4: synthetic auxin

Chemical family Pyridine