Summer Annual Grasses in Established Stands

sethoxydim (Poast or Poast Plus)

Rate 0.19 to 0.47 lb ai/a (1 to 2.5 pints/a Poast)

Time Apply to actively growing annual or perennial grasses at stage of grass growth indicated on label.

Remarks See label for specific herbicide rates, weed species, and weed size. Always add a nonphytotoxic oil concentrate to the spray tank at 2 pints/a. Sethoxydim is most effective on actively growing grasses before they are cut or reach the maximum size indicated on label. Larger, more mature grasses can be controlled, but two applications may be required. Sethoxydim will not control annual bluegrass or any of the fine fescues.

Caution Control often is erratic on grasses stressed by drought, temperature extremes, insect damage, herbicide injury, or other factors. Do not apply if rain is expected within 1 hour after application. Do not apply within 7 days of feeding, grazing, or harvesting for green chop or silage, or within 14 days of harvesting hay. Do not exceed 0.94 lb ai/a in one season.

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

Chemical family Cyclohexanedione

trifluralin (Treflan TR-10 or Treflan HFP)

Rate 2 lb ai/a

Time Apply before weeds emerge.

Remarks Trifluralin must be activated by a single rain or overhead sprinkler irrigation of at least 0.5 inch, or by furrow irrigation that thoroughly wets the beds between furrows. If not activated within 3 days, mechanically incorporate trifluralin with equipment that will not damage the alfalfa. May be applied during dormancy or during the growing season after a cutting. Apply before weeds are expected to germinate; trifluralin will not control established weeds.

Caution Do not cut for hay or graze within 21 days of application. Apply no more than 2 lb ai/a per growing season. If rotating out of established alfalfa the year after applying, plant only crops for which trifluralin can be applied as a preplant treatment, because injury may result.

Site of action Group 3: microtubule assembly inhibitor

Chemical family Dinitroaniline