Ragweed, common (Ambrosia artemisiifolia) and related species

2,4-D ester

Rate 2 lb ae/a

Time Apply after all plants have emerged but before flowering.

Remarks Foliage must be thoroughly wet. Use 50 gal/a of water.

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 plants.

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

clopyralid + 2,4-D amine (Curtail)

Rate 1 to 5 quarts/a Curtail

Time Apply to actively growing weeds after most basal leaves emerge but before bud stage.

Remarks Use lower rate for in-crop cereal grain application, higher rates for fallow, postharvest, and Conservation Reserve Program (CRP) applications. Consult label for specific directions. With CRP applications, for established grass only. For best results, wait at least 20 days after application before disturbing treated areas (cultivation, mowing, fertilization with shank-type applicators) to allow for thorough translocation. Apply in enough total spray volume to ensure good coverage.

Caution Consult label for crop rotation restrictions before using product. Several crops may be injured up to 4 years after application.

Site of action (both) Group 4: synthetic auxin

Chemical family (clopyralid) Pyridine; (2,4-D) Phenoxy acetic acid

glyphosate

Rate 0.75 to 1.5 lb ae/a. Make wiper application solutions with a 10 to 33% glyphosate solution. Use a 1% glyphosate solution with hand-held and high-volume equipment.

Time Use the 0.75-lb rate when ragweed is less than 6 inches tall.

Remarks Apply to actively growing plants.

Caution Glyphosate controls grasses as well as other vegetation in treated areas.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted