Cress, hoary or whitetop (Lepidium draba), hairy (Lepidium appelianum), and lens-podded (Lepidium chalepensis)

2,4-D LV ester or 2,4-D amine

Rate 2 to 3 lb ae/a in non-cropland and 1 lb ae/a as a selective treatment

Time Apply early in cress growth stage; control is minor after bud stage. In cereals, apply 2,4-D before weeds reach boot stage.

Remarks When possible, use 2,4-D on whitetop plants before plowing fields in spring. Re-spray in fall if new growth appears.

Caution Avoid drift to sensitive crops.

Site of action Group 4: synthetic auxin

Chemical family Phenoxy acetic acid

aminocyclopyrachlor + chlorsulfuron (Perspective)

Rate 1.2 to 1.8 oz/a aminocyclopyrachlor + 0.5 to 0.7 oz/a chlorsulfuron (3 to 4.5 oz/a of product)

Time Apply to actively growing vegetation.

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

chlorsulfuron (Telar)

Rate 0.75 oz ai/a (1 oz/a of 75% ai Telar)

Time Apply at prebloom to bloom growth stage or to rosettes in fall.

Remarks Using an 80% ai surfactant increases effectiveness.

Caution Apply only to pasture, range, Conservation Reserve Program (CRP), and non-crop sites.

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

Chemical family Sulfonylurea

imazapic (Plateau)

Rate 0.125 to 0.188 lb/a

Time Apply after blossoms open (full bloom) until plants desiccate. Fall rosettes also may be treated.

Remarks Add 1 quart/a methylated seed oil.

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) of the 60% ai

Time Apply at prebloom to bloom growth stage or to rosettes in fall.

Remarks Using a nonionic or silicone surfactant increases effectiveness. Application sites differ between products; consult label.

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

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

Chemical family Sulfonylurea