Preharvest Weed Control

2,4-D (several trade names)

Rate 0.5 lb ae/A

Time Apply when grain is in the hard dough stage.

Remarks Controls weeds that interfere with harvest or suppresses perennial weeds. REI 12 hr for the low volatile ester (LVE) formulation and 48 hr for the amine formulation.

Caution Do not apply to fields underseeded to legumes. Do not graze treated grain fields within 14 days after treatment. The preharvest interval is 14 days. Maximum of 1.75 lb ae (3.6 pints/A) per crop cycle. Limited to one preharvest application per crop cycle.

Site of action Group 4: synthetic auxin

Chemical family Phenoxy acetic acid

carfentrazone (Aim EC)

Rate Apply up to 0.031 lb ai/A (apply up to 2 fl oz/A Aim EC)

Time Apply when crop is mature and grain has begun to dry down. Do not apply within 7 days of harvest.

Remarks Use methylated seed oil (MSO) or crop oil concentrate (COC) at 1 to 2 % v/v (1 to 2 gal/100 gal of spray solution) for harvest aid. A high-quality sprayable liquid nitrogen fertilizer may be used at 2% to 4% v/v (2 to 4 gal/100 gal spray solution) or ammonium sulfate (AMS) at 2 to 4 lb/A in addition to the MSO or COC. Coverage is essential for satisfactory performance. Repeat application if necessary. REI 12 hr.

Caution If applied as a tank-mixture, refer to the other product's label for restrictions on tank-mixing, and follow all label precautions, instructions, and rotational cropping restrictions. Do not apply this product through any irrigation system.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Triazolone

dicamba (Clarity and others)

Rate 0.25 lb ae/A (8 fl oz/A Clarity)

Time Apply when wheat is in the hard dough stage and the green color is gone from the nodes (joints) of the stem. Best results will be obtained if application can be made when weeds are actively growing, but before weeds canopy.

Remarks A waiting interval of 7 days is required before harvest. Dicamba may be tank-mixed with other herbicides such as metsulfuron, glyphosate, and 2,4-D for additional broadleaf or grass weed control. REI 24 hr.

Caution Do not apply this product through any irrigation system. Do not use preharvest-treated wheat for seed unless a germination test is performed on the seed with an acceptable result of 95% germination or better.

Site of action Group 4: synthetic auxin

Chemical family Benzoic acid

glyphosate (several trade names)

Rate 0.75 lb ae/A

Time Apply after wheat reaches hard dough stage and grain moisture is less than 30%.

Remarks Be aware that glyphosate is formulated as 3 lb, 4 lb, 4.17 lb, 4.5 lb, and 5 lb ae/gal; be sure to use the correct amount of herbicide. Consult label for adjuvant need. Apply in 3 to 10 gal/A by air or ground. Preharvest interval is 7 days. REI 4 hr.

Caution Do not let glyphosate drift off target. Do not apply to wheat grown for seed.

Site of action Group 9: inhibits EPSP synthase

Chemical family Glycine

metsulfuron (Ally XP) + 2,4-D or glyphosate

Rate 0.06 oz ai/A (0.1 oz/A Ally XP)

Time Make applications after the crop has reached the hard dough stage, but no later than 10 days before harvest.

Remarks Used in combination with 2,4-D at 0.25 to 0.5 lb ai/A plus nonionic surfactant (NIS) at 0.25 to 0.5% v/v (1 to 2 quarts/100 gal spray solution) or glyphosate at 0.375 to 0.75 lb ae/A will typically aid in dry down of many broadleaf weeds. Weeds must be actively growing for herbicide to be effective. Consult glyphosate label or local recommendations for the amount of adjuvant to include. REI 4 hr.

Caution Do not use on soils above pH 7.9. Metsulfuron can persist in soil. Do not apply this product through any irrigation system. Carefully follow label instructions regarding crop rotations. Many crops cannot be planted within 2 years or longer after applying.

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

Chemical family Sulfonylurea

saflufenacil (Sharpen)

Rate 0.022 to 0.045 lb ai/A (1 to 2 fl oz/A Sharpen)

Time Apply only to wheat that has reached physiological maturity (hard-dough stage; grain contains less than 30% moisture) or according to Extension Service recommendations in the use area. Allow up to 7 days for optimum desiccation effect depending on environmental conditions.

Remarks A methylated seed oil (MSO) plus ammonium-based adjuvant system is required for optimum desiccation activity and weed control. See label for more information on adjuvants and tank-mixes. Pre-harvest interval is 3 days. REI 12 hr.

Caution Do not apply more than a maximum cumulative amount of 2.0 fl oz/A of Sharpen per cropping season for desiccation purposes.

Site of action Group 14: protoporphyrinogen oxidase inhibitor

Chemical family Pyrimidinedione