clethodim (Select 2EC, 2 lb ai/gal)
Rate 6 to 16 fl oz/a (0.094 to 0.25 lb ai/a). See label for recommended rates on specific grass species and growth stages. Use the high rate under heavy grass pressure and/or when grasses have reached maximum height. Do not exceed a total of 32 fl oz/a per season. Does not control broadleaves.
Time Apply to actively growing grasses with recommended weed heights. Apply when the first grass species in a mixed-grass-weed population reaches the recommended growth stage for treatment. Where irrigation supplements limited rain, apply Select as soon as possible within 7 days after irrigation. In arid regions, a second application generally controls perennial grasses more effectively than a single application. Make the second application 2 to 3 weeks after the first. Do not apply a postemergence broadleaf herbicide within 1 day after a Select application; grass control may be reduced. Do not cultivate less than 7 days before or after applying Select. Do not apply Select if rain is expected within 1 hour after application. Preharvest interval is 30 days.
Application methods Ground or aerial. Always use a crop oil concentrate (COC), 1 quart/a COC for ground applications and 1% v/v (but not less than 1 pint/a) COC for aerial applications. One to 2 quarts/a liquid fertilizer or 2.5 to 4 lb/a spray-grade ammonium sulfate (AMS) may be added to the spray mix in addition to COC. Adding AMS improves control for difficult species such as quackgrass, wild oat, volunteer cereals, or volunteer corn. Do not apply by chemigation.
Remarks Select controls annual and perennial grasses; Select does not control sedges or broadleaves. Do not apply to stressed grass plants; control may be reduced. Perennial grass control is best if rhizomes or stolons are cut up before planting crop, to stimulate maximum emergence of grass shoots. Minor leaf spotting on treated potato plants may occur under certain environmental conditions, but new foliage will be unaffected.
Caution Grass crops such as corn, sorghum, rice, small grains, and turf are highly sensitive to Select. The Select 2EC label does not specify uses in potato grown for seed.
Tank-mixtures Mixtures of Select and broadleaf herbicides may reduce grass control. An additional Select application may be necessary. Do not apply Select if broadleaf weeds are tall or dense enough to prevent proper coverage. Read and follow applicable "Restrictions and Limitations and Directions for Use" on all product labels in a tank-mixture. The most restrictive labeling applies to use of tank-mixtures.
Re-cropping restrictions None on the label.
Rotational cropping restrictions None on the label.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Cyclohexanedione
sethoxydim (Poast 1.5 lb ai/gal; or Poast Plus 1.0 lb ai/gal)
Rate Most annual grasses: 1.5 pints/a Poast; or 2.25 pints/a Poast Plus (0.28 lb ai/a). Volunteer cereals: 2 pints/a Poast or 3 pints/a Poast Plus (0.375 lb ai/a). See the quackgrass and wild oat sections for specific rates and directions for control of these grasses. Does not control broadleaves.
Time Apply to actively growing annual grasses at stage of grass growth indicated on label. To control volunteer cereals, apply before tillering up to 4 inches tall. Do not cultivate within 5 days before or 7 days after application. Cultivating 7 days or later after application may help provide season-long control. Do not apply within 30 days of harvest.
Application methods Ground or aerial. In irrigated areas, it may be necessary to irrigate before treatment to ensure active weed growth. Always add a nonphytotoxic oil concentrate to the spray tank at 32 oz/a or methylated seed oil at 20 oz/a or Dash HC at 16 oz/a.
Remarks See labels for specific rates for weed species and weed size. Poast or Poast Plus is most effective on actively growing grasses before they reach the maximum size listed on label. Larger, more mature grasses can often be controlled but may require two applications. Poast or Poast Plus will not control annual bluegrass or any of the fine fescues and is relatively weak on downy brome.
Caution Control may be 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 through any type of irrigation equipment.
Tank-mixtures Poast or Poast Plus can only be tank mixed with metribuzin in potatoes. Read and follow applicable "Restrictions and Limitations and Directions for Use" on all product labels in a tank-mixture. The most restrictive labeling applies to use of tank-mixtures. Do not apply this tank-mix if grasses to be controlled include rhizome Johnsongrass, quackgrass, Bermudagrass, wirestem muhly, volunteer corn or cereal, shattercane, red rice, or itchgrass.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibito
Chemical family Cyclohexanedione