Quackgrass

clethodim (Select, Select Max and several other trade names)

Rate 0.125 to 0.25 lb ai/a (8 to 16 fl oz/a Select 2EC) or 0.091 to 0.121 lb ai/a (12 to 32 fl oz/a Select Max 0.97EC)

Time Apply to actively growing grasses 4 to 12 inches tall.

Remarks Apply when the first species in a mixed-grass weed population reaches the recommended growth stage for treatment. Be aware that clethodim is formulated as 0.97, 2, and 3 lb ai/gal; be sure to use the correct amount of herbicide. Always use crop oil concentrate at 1% v/v (1 gal/100 gal spray solution). Adding 2.5 to 4 lb AMS fertilizer enhances quackgrass control. Do not apply to grasses that are stressed due to moisture, temperature, and/or very low humidity. Do not apply if rain is expected within 1 hour of application. See label on tank mixing with broadleaf herbicides. Restricted entry interval (REI) is 24 hours.

Caution Do not apply within 40 days of harvesting beets. Do not apply more than 64 fl oz/a per season.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor

Chemical family Cyclohexanedione

quizalofop P-ethyl (Assure II or Targa)

Rate 0.069 to 0.083 lb ai/a (10 to 12 fl oz/a Assure II 0.88EC or Targa 0.88EC)

Time Apply to actively growing quackgrass 6 to 10 inches tall.

Remarks Two applications more effectively control quackgrass than one application. Use a petroleum-based crop oil concentrate at 1% v/v (4 quarts/100 gal spray solution) or a nonionic surfactant at 0.25% v/v (1 quart/100 gal spray solution). For aerial applications apply 0.5% v/v (2 quarts/100 gal spray solution) of crop oil concentrate. Do not apply if rain is expected within 1 hour of application. Restricted entry interval (REI) is 12 hours.

Caution Do not apply more than 28 fl oz/a per season. Do not mix with broadleaf herbicides unless listed on the label. Do not apply through any type of irrigation equipment. Do not harvest with 45 days after application.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor

Chemical family Aryloxyphenoxy propionate

sethoxydim (Poast)

Rate 0.47 lb ai/a first application + 0.28 lb ai/a second application (2.5 + 1.5 pints/a Poast 1.5EC)

Time Apply first when quackgrass is 6 to 8 inches tall. Apply again when regrowth or new growth is 6 to 8 inches tall.

Remarks Quackgrass is suppressed during crop season, but little long-term control will result. Use an oil concentrate with herbicide. Add nitrogen to COC or MSO to improve control. Cultivate 7 to 14 days after first or sequential applications. Do not apply if rain is expected within 1 hour of application. Restricted entry interval (REI) is 12 hours.

Caution Do not exceed 2.5 pints/a Poast per application or 5 pints/a Poast in 1 year. Apply at least 60 days before harvest.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor

Chemical family Cyclohexanedione

fluazifop (Fusilade DX)

Rate 0.125 to 0.188 lb ai/a (8 to 12 fl oz/a Fusilade DX 2EC)

Time Apply to actively growing quackgrass 6 to 10 inches tall.

Remarks Make two applications: the first one at 6 to 10 inches tall and the second one 2 to 3 weeks later, but before quackgrass exceeds 10 inches tall. Apply with 1% crop oil concentrate or once-refined vegetable oil concentrate containing 15% to 20% approved emulsifier (0.5 to 1 gal/100 gal spray solution). Fusilade is rainfast 1 hour after application. Restricted entry interval (REI) is 12 hours.

Caution Do not use flood-type or other spray nozzle tips that deliver coarse, large droplet sprays. Do not exceed 48 fl oz/a per season. Do not harvest sugar beets within 90 days of last application.

Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor

Chemical family Aryloxyphenoxy propionate