EPTC (Eptam 7E, 7 lb ai/gal)
Rate 3.5 to 7 pints/a (3 to 6 lb ai/a)
Time Apply and immediately incorporate into soil before planting potatoes or after clean cultivation.
Remarks If applied preplant, thoroughly incorporate into soil immediately after applying 2 to 3 inches deep by cross-disking 4 to 6 inches deep or by tilling with a power-driven rotary tiller cutting 2 to 3 inches deep. If applied after planting, incorporate either mechanically into the top 2 to 3 inches of soil or by sprinkler irrigation. See previous entries in this section for application and incorporation methods, remarks, cautions, re-cropping and rotational cropping restrictions, and site of action and chemical family information for this herbicide.
Site of action Group 8: lipid synthesis inhibitor but not an ACCase inhibitor
Chemical family Thiocarbamate
Paraquat (SL or Inteon, 2 lb paraquat cation/gal; Firestorm, 3 lb paraquat cation/gal; or others or glyphosate (various formulations)
Rate Apply to fallow ground before planting potatoes: 1.5 to 4 pints/a Gramoxone SL or Inteon (0.75 to 1 lb ae/a); after planting and before potatoes emerge: 1 to 2 pints Gramoxone SL or Inteon (0.5 to 1 lb ae/a) or 1.3 pints/a (0.49 lb ae/a) Firestorm + a nonionic surfactant with 75% or more surface-active agent at 0.125% v/v (1 pint/100 gal spray mix) or crop oil concentrate at 1% v/v (1 gal/100 gal spray mix) for ground applications or 1 pint/a for aerial applications. Glyphosate: 0.38 lb ae/a.
Time Apply Gramoxone SL or Inteon to fallow ground before planting potatoes. Apply Gramoxone SL or Inteon, Firestorm, or glyphosate before potatoes emerge.
Remarks These materials control only wild oat emerged at the time of application. Wild oat emerging later will not be controlled. Some glyphosate formulations require nonionic surfactant; see label for details. Adding 1 to 2% dry ammonium sulfate (AMS) by weight or 8.5 to 17 lb/100 gal spray-mix may increase performance. The equivalent rate of AMS in a liquid formulation also may be used.
Caution Paraquat is a restricted-use herbicide. Do not apply either paraquat or glyphosate if potatoes have emerged, because crop may be injured. See previous entries in this section for application and incorporation methods, remarks, cautions, re-cropping and rotational cropping restriction, and site of action and chemical family information for this herbicide.
Site of action (paraquat) Group 22: photosystem 1 electron diversion; (glyphosate) Group 9: inhibits EPSP synthase
Chemical family (paraquat) bipyridilium; (glyphosate) none generally accepted
rimsulfuron (Matrix SG; Matrix FNV; Solida; or others, 25%)
Rate 1 to 1.5 oz/a (0.0156 to 0.023 lb ai/a rimsulfuron + nonionic surfactant at 0.125% to 0.25% v/v (1 to 2 pints/100 gal spray solution) or 1% v/v (1 gal/100 gal spray solution) crop oil concentrate or methylated seed oil if weeds are emerged.
Time May be applied preemergence after hilling or dragoff but before potatoes and wild oat emerge or postemergence to wild oat in the two- to four-leaf stage (3 to 5 inches tall).
Remarks Tank-mixes are in Annual Grass and Broadleaf Weeds section. See previous entries in this section for application and incorporation methods, remarks, cautions, re-cropping and rotational cropping restrictions, and site of action and chemical family information for this herbicide.
Caution Applied postemergence, rimsulfuron may temporarily yellow potato foliage. Under environmental stress (cool, wet, or hot or humid weather), rimsulfuron applied postemergence also may stunt growth and cause leaf malformations. Potatoes recover within 7 to 15 days. To reduce potential injury, apply only if the weather has been sunny for at least 3 successive days. Do not use on seed potatoes unless permitted by a supplemental label.
Site of action Group 2: acetolactate synthase (ALS) inhibitor
Chemical family Sulfonylurea
sethoxydim (Poast, 1.5 lb ai/gal; or Poast Plus, 1 lb ai/gal)
Rate 1.5 pints/a Poast; or 2.25 pints/a Poast Plus (0.28 lb ai/a)
Time Apply to actively growing wild oat up to 4 inches tall.
Remarks Always add a nonphytotoxic oil concentrate to the spray tank at 2 pints/a or methylated seed oil at 20 oz/a or Dash HC at 16 oz/a. Depending on the crop, the addition of ammonium nitrate or ammonium sulfate is recommended.
Caution Control may be erratic on grasses stressed by drought, temperature extremes, insect damage, herbicide injury, and other factors. Do not apply if rain is expected within 1 hour after applying. Do not cultivate within 5 days before or 7 days after applying. Preharvest interval is 30 days. Poast or Poast Plus can only be tank mixed with metribuzin in potatoes. See previous entries in this section for application and incorporation methods, remarks, cautions, re-cropping and rotational cropping restrictions specific to this herbicide.
Site of action Group 1: acetyl CoA carboxylase (ACCase) inhibitor
Chemical family Cyclohexanedione