Snakeweed, broom (Gutierrezia sarothrae)

aminocyclopyrachlor + metsulfuron methyl (Streamline)

Rate 1.9 to 3.8 oz/a aminocyclopyrachlor + 0.6 to 1.2 oz/a metsulfuron (4.75 to 9.5 oz/a of product)

Time Apply to actively growing woody plants.

Remarks Adjuvants can be used; they 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. There are several application methods that dictate the amount of product to be mixed with the carrier, so consult the label. In addition to woody species, controls many herbaceous species also.

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. Conifers can be injured, these include ponderosa pine, Douglas fir, Norway spruce, and white pine. Other trees that can be injured include aspen, Chinese tallow, cottonwoods, honey locust, magnolia, poplars, redbud, silver maple, and willow. Applications to stressed plants may reduce control. Do not allow spray to drift off target.

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

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

metsulfuron (Escort and others)

Rate Escort: 0.45 oz ai/a (0.75 oz/a)

Time Apply in fall or spring.

Remarks Application sites differ among products; consult labels.

Caution Prevent drift to 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 0.25 to 0.5 lb ae/a

Time Full leaf development to early bloom stage.

Remarks Plants should be actively growing at time of treatment.

Caution Most formulations are restricted-use herbicides. Do not contaminate water. Beans, potatoes, and many other broadleaf crops are very sensitive to picloram. Do not use in diversified cropping areas. See label for grazing restrictions. Apply rates above 0.5 lb ae/a (1 quart/a) only as a spot treatment not to exceed 25% of a landowner's acreage in a given watershed in one season.

Site of action Group 4: synthetic auxin

Chemical family Pyridine