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How to Manage Pests

UC Pest Management Guidelines

| More pests | More crops | About guidelines |

Ripgut brome, Bromus diandrus.

Small Grains

Herbicide Treatment Table

(Reviewed 2/07, updated 2/07)

In this Guideline: More about weeds in small grains:
Common name Amount/Acre R.E.I.+ P.H.I.+
(trade name)   (hours) (days)
When choosing an herbicide, an important factor to consider is the developmental growth stage of the crop (see DEVELOPMENTAL GROWTH STAGES). Also consider information relating to environmental impact.
 
FALLOW PERIOD
A. DICAMBA* 0.25–2.0 lb a.i. 24 0
  (Banvel, Clarity)
  MODE OF ACTION: A benzoic acid (Group 4)1 herbicide.
  COMMENTS: Apply after harvest. Use high rates for perennial weeds, but do not exceed 2 lb during any fallow periods. See label for rotational restrictions. Banvel can be used before planting wheat, but Clarity can be used before planting barley, oats, triticale, and wheat.
 
B. PARAQUAT* 0.47 lb a.i.    
  (Gramoxone Inteon)   12 45
  MODE OF ACTION: A bipyridylium (Group 22)1 herbicide.
  COMMENTS: A nonselective, postemergence herbicide; for use before planting wheat. Apply with nonionic surfactant before weeds are 6 inches tall. No soil residual activity. Good coverage is essential.
 
C. GLYPHOSATE 0.38–0.5 lb a.i. 4 0
  (Roundup)
  MODE OF ACTION: A glycine (Group 9)1 herbicide.
  COMMENTS: A nonselective, translocated, postemergence herbicide; apply with nonionic surfactant anytime. Use higher rates for larger weeds, perennials, etc. Can be mixed with 2,4-D or dicamba (see 2,4-D and dicamba labels for restrictions on tank mix combinations).
 
D. 2,4-D* 1–2 lb a.i. 12 0
  MODE OF ACTION: A phenoxy-carboxylic-acid (Group 4)1 herbicide.
  COMMENTS: For use on fallow ground before barley, rye, and wheat. Apply when weeds are actively growing. Do not replant for 3 months; may be followed by barley, rye, and wheat. Does not kill grasses. Do not graze within 7 days of treatment.
 
PREPLANT or PREEMERGENCE TO CROP
A. PARAQUAT* 0.49–1 lb a.i.    
  (Gramoxone Inteon)   12 0
  MODE OF ACTION: A bipyridylium (Group 22)1 herbicide.
  COMMENTS: For use on barley and wheat only. Rate varies with weed size; use lower rate on weeds
1-3 inches tall. Do not graze livestock in treated areas or harvest for forage hay.
 
B. GLYPHOSATE 0.38–0.5 lb a.i.    
  (Roundup)   4 0
  MODE OF ACTION: A glycine (Group 9)1 herbicide.
  COMMENTS: A nonselective, translocated, postemergence herbicide; apply with nonionic surfactant anytime. Use higher rates for larger weeds, perennials, etc. Can be mixed with 2,4-D or dicamba (see 2,4-D and dicamba labels for restrictions on tank mix combinations).
 
POSTPLANT - WHEAT
  After weeds emerge
A. TRALKOXYDIM 0.18-0.24 lb a.i.    
  (Achieve) 6.9-9.2 oz 12 60 (see comments)
  MODE OF ACTION: A cyclohexanedione (Group 1) 1 herbicide.
  COMMENTS: Selective grass herbicide; apply when up to 4- to 6-leaf stage of grass, depending on species (see label). Can be used on wheat, durum wheat, and barley up to flag leaf stage under a Section 2(ee) recommendation. Apply when weeds are in the 4-leaf stage or earlier and are not stressed. Immature crops (forage) may be grazed or cut for hay 30 days after treatment. Mature straw and grain may be fed to livestock 45 days after treatment. Can be tank mixed with broadleaf herbicides. Always add Supercharge adjuvant to the spray solution. In addition, add ammoniom sulfate at rate of 7-15 lb/100 gal.
 
B. DICAMBA* 0.062–0.125 lb a.i.    
  (Banvel, Clarity) 2–4 oz 24 0
  MODE OF ACTION: A benzoic acid (Group 4)1 herbicide.
  COMMENTS: Apply when crop has 2-3 leaves (before well-tillered) and weeds have 2-3 leaves. Do not apply by air if sensitive crops are nearby. Usually mixed with MCPA. Injury increases when mixed with other broadleaf herbicides. May cause grain to temporarily flatten. Use is restricted in some counties.
 
C. BROMOXYNIL 0.25–0.38 lb a.i.    
  (Buctril) 1–1.5 pt 12 0
  MODE OF ACTION: A nitrile (Group 6)1 herbicide.
  COMMENTS: Apply to crop from 2-leaf stage until just before boot. For best results, apply when weeds are in early seedling stage. Does not effectively control wild mustard greater than 3 inches in diameter. Do not graze for 45 days. A minimum of 10 gal water/acre is essential for best control, especially when weeds are larger or if small grain is developing a thick canopy.
 
D. FENOXAPROP
  (Puma) 1EC Label rates 24 70
  MODE OF ACTION: An FOP (Group 1)1 herbicide.
  COMMENTS: For use on wheat and barley; apply to the crop from 2nd leaf up to 70 days before harvest. May be tank mixed with bromoxynil. Rainfall within 1 hour of application will reduce weed control.
 
E. MESOSULFURON-METHYL
  (Osprey) 4.75 oz 4 60
  MODE OF ACTION: A sulfonylurea (Group 2) 1 herbicide.
  COMMENTS: For control of annual grass and broadleaf weeds in winter wheat. Can be applied from wheat emergence up to the jointing stage. Apply with either a methylated seed oil or a basic blend type adjuvant. Use ammonium nitrogen fertilizer if using methylated seed oil to improve control. Do not make more than 1 application per growing season.
 
F. CARFENTRAZONE
  (Shark) Label rates 12 7 - forage
  MODE OF ACTION: A triazolinone (Group 14) 1 herbicide.
  COMMENTS: For selective postemergence control of broadleaf weeds in wheat, barley, and oats. For best control apply before weeds are greater than 4 inches in height.
 
G. CLOPYRALID
  (Stinger) Label rates 12 see comments
  MODE OF ACTION: A pyridine-carboxylic-acid (Group 4)1 herbicide.
  COMMENTS: Do not permit lactating dairy animals or meat animals being finished for slaughter to forage or graze treated grain fields within 1 week after treatment. Do not harvest hay from treated grain fields. See other label restrictions regarding grazing and use of hay, straw, and manure from treated fields.
 
H. CHLORSULFURON 0.008–0.015 lb a.i. 4 45
  (Glean)
  MODE OF ACTION: A sulfonylurea (Group 2)1 herbicide.
  COMMENTS: Apply to crop from 2-3 leaves until boot and weeds are less than 2 inches tall or 2 inches across. Use with surfactant. Do not apply on soils above pH 7.5. Apply on land used only for small grains. Do not apply more than 0.015 lb/acre/18 month period. Also has soil activity to control weeds as they germinate. Soil residual activity can injure crops other than wheat, barley, or oats for 2-3 years or more.
 
I. MCPA AMINE* 0.23–0.46 lb a.i.    
    0.5–1 pt 48 0
  MODE OF ACTION: A phenoxy-carboxylic-acid (Group 4)1 herbicide.
  COMMENTS: Apply to crop from 3- to 4-leaf stage until just before boot. Less injurious than 2,4-D at early crop stages. Restricted use between Feb 15 and Oct 15.
 
J. 2,4-D AMINE* 0.31–0.87 lb a.i. 48 see comments
  MODE OF ACTION: A phenoxy-carboxylic-acid (Group 4)1 herbicide.
  COMMENTS: Apply to crop only at the well-tillered stage. Application before well-tillered and after jointing stage may cause yield reductions; barley more susceptible than wheat. Use restricted in some counties. Immature crops (forage) may be grazed or cut for hay 30 days after treatment. Mature straw and grain may be fed to livestock 45 days after treatment.
 
POSTPLANT - BARLEY
  After weeds emerge
A. TRALKOXYDIM 0.18-0.24 lb a.i.    
  (Achieve) 6.9-9.2 oz 12 60
  MODE OF ACTION: A cyclohexanedione (Group 1) 1 herbicide.
  COMMENTS: Selective grass herbicide; apply when up to 4- to 6-leaf stage of grass, depending on species (see label). Can be used on wheat, durum wheat, and barley up to flag leaf stage under a Section 2(ee) recommendation. Can be tank mixed with broadleaf herbicides. Always add Supercharge adjuvant to the spray solution. In addition, add ammoniom sulfate at rate of 7-15 lb/100 gal.
 
B. BROMOXYNIL 0.25–0.38 lb a.i.    
  (Buctril) 1–1.5 pt 12 0
  MODE OF ACTION: A nitrile (Group 6)1 herbicide.
  COMMENTS: Apply to crop from 2-leaf stage until just before boot. For best results, apply when weeds are in early seedling stage. Does not effectively control wild mustard greater than 3 inches in diameter. Do not graze for 45 days. Use a minimum of 10 gal water/acre for best control, especially when weeds are larger or if small grain is developing a thick canopy.
 
C. CHLORSULFURON 0.008–0.015 lb a.i. 4 45
  (Glean)
  MODE OF ACTION: A sulfonylurea (Group 2)1 herbicide.
  COMMENTS: Apply to crop from 2-3 leaves until boot and weeds are less than 2 inches tall or 2 inches across. Use with surfactant. Do not apply on soils above pH 7.9. Use only on dry land conditions. Do not apply more than 0.015 lb/acre/18 month period. Also has soil activity to control weeds as they germinate. Soil residual activity can injure crops other than wheat, barley, or oats for 2-3 years or more.
 
D. CARFENTRAZONE
  (Shark) Label rates 12 7 - forage
  MODE OF ACTION: A triazolinone (Group 14) 1 herbicide.
  COMMENTS: For selective postemergence control of broadleaf weeds in wheat, barley, and oats. For best control apply before weeds are greater than 4 inches in height.
 
E. MCPA AMINE* 0.23–0.46 lb a.i.    
    0.5–1 pt 48 0
  MODE OF ACTION: A phenoxy-carboxylic-acid (Group 4)1 herbicide.
  COMMENTS: Apply to crop from 3- to 5-leaf stage to early jointing. Restricted use between Feb 15 and Oct 15.
 
F. 2,4-D AMINE* 0.26–0.95 lb a.i. 48 see comments
  MODE OF ACTION: A phenoxy-carboxylic-acid (Group 4)1 herbicide.
  COMMENTS: Apply to crop only at the well-tillered stage. Application before well-tillered and after jointing stage may cause yield reductions. Barley more susceptible than wheat. Restricted use between Feb 15 and Oct 15. Do not permit lactating dairy animals or meat animals being finished for slaughter to forage or graze treated grain fields within 1 week after treatment. Do not feed treated straw to livestock.
 
G. FENOXAPROP
  (Puma) 1EC Label rates 24 70
  MODE OF ACTION: An FOP (Group 1)1 herbicide.
  COMMENTS: For use on wheat and barley; apply to the crop from 2 leaf up to 70 days before harvest. May be tank mixed with bromoxymil. Rainfall within 1 hour of application will reduce weed control. For use on wheat and barley.
 
H. CLOPYRALID
  (Stinger) Label rates 12 0
  MODE OF ACTION: A pyridine-carboxylic-acid (Group 4)1 herbicide.
  COMMENTS: Do not permit lactating dairy animals or meat animals being finished for slaughter to forage or graze treated grain fields within 1 week after treatment. Do not harvest hay from treated grain fields. See other label restrictions regarding grazing and use of hay, straw, and manure from treated fields.
 
POSTPLANT - OATS
After weeds emerge
A. DICAMBA* 0.062–0.125 lb a.i.    
  (Banvel, Clarity) 2–4 oz 24 0
  MODE OF ACTION: A benzoic acid (Group 4)1 herbicide.
  COMMENTS: Apply to oats before 5-leaf stage and weeds have 2-3 leaves. Do not apply by air if sensitive crops are nearby. When mixed with MCPA and bromoxynil injury is more likely to occur.
 
B. BROMOXYNIL 0.25–0.38 lb a.i.    
  (Buctril) 1–1.5 pt 12 0
  MODE OF ACTION: A nitrile (Group 6)1 herbicide.
  COMMENTS: Apply to crop from emergence until just before boot stage. For best results, apply when weeds are in early seedling stage. Does not effectively control wild mustard greater than 3 inches in diameter. May temporarily burn oats. Do not graze for 45 days.
 
C. CHLORSULFURON
  (Glean) 0.008–0.015 lb a.i. 4 45
  MODE OF ACTION: A sulfonylurea (Group 2)1 herbicide.
  COMMENTS: Apply to crop from 2-3 leaves until boot and weeds are less than 2 inches tall or 2 inches across. Use with surfactant. Do not apply on soils above pH 7.9. Use on land used only for small grains. Do not apply more than 0.021 lb a.i./acre/18 month period. Must be tank mixed with dicamba or bromoxynil if weeds are present at application time.
 
D. CARFENTRAZONE
  (Shark) Label rates 12 7 - forage
  MODE OF ACTION: A triazolinone (Group 14) 1 herbicide.
  COMMENTS: For selective postemergence control of broadleaf weeds in wheat, barley, and oats. For best control apply before weeds are greater than 4 inches in height.
 
E. MCPA AMINE* 0.25–0.5 lb a.i.    
    0.5–1 pt 48 0
  MODE OF ACTION: A phenoxy-carboxylic-acid (Group 4)1 herbicide.
  COMMENTS: Apply to oats from 3- to 5-leaf stage to early jointing. Restricted use between Feb 15 and Oct 15.
 
F. CLOPYRALID
  (Stinger) Label rates 12 see comments
  MODE OF ACTION: A pyridine-carboxylic-acid (Group 4)1 herbicide.
  COMMENTS: Do not permit lactating dairy animals or meat animals being finished for slaughter to forage or graze treated grain fields within 1 week after treatment. Do not harvest hay from treated grain fields. See other label restrictions regarding grazing and use of hay, straw, and manure from treated fields.
 
 
+  Restricted entry interval (R.E.I.) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of these two intervals is the minimum time that must elapse before harvest.
* Permit required from county agricultural commissioner for purchase or use.
1 Group numbers are assigned by the Weed Science Society of America (WSSA) according to different modes of action. Although weeds may exhibit multiple resistance across many groups, mode of action numbers are useful in planning mixtures or rotations of herbicides with different modes of action. For more information, see http://www.plantprotection.org/HRAC/.

[Precautions]

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Small Grains
UC ANR Publication 3466
Weeds
W. M. Canevari, UC Cooperative Extension, San Joaquin County
R. N. Vargas, UC Cooperative Extension, Madera County
S. D. Wright, UC Cooperative Extension, Tulare County
H. L. Carlson, ANR, UC Davis
L. F. Jackson, Agronomy, UC Davis
J. E. Hill, Agronomy, UC Davis
Acknowledgment for contributions to the weeds section:
M. J. Smith, UC Cooperative Extension, San Luis Obispo County
C. E. Bell, UC Cooperative Extension, San Diego County
D. W. Cudney, Botany and Plant Sciences, UC Riverside

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