Small Grains

Agricultural pest management


Ripgut brome, Bromus diandrus.

Herbicide Treatment Table

(Reviewed 2/07, updated 2/09, pesticides updated 7/16)

In this Guideline: More about weeds in small grains:

Common name Amount per acre REI‡ PHI‡
(Example trade name)   (hours) (days)

UPDATED: 7/16
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Bee precaution pesticide ratings
The following are listed alphabetically. When choosing a pesticide, consider information relating to environmental impact, resistance management, the pesticide's properties, and application timing. Not all registered pesticides are listed. Always read the label of the product being used.
 
NOTE: When choosing an herbicide, an important factor to consider is the developmental growth stage of the crop (see DEVELOPMENTAL GROWTH STAGES).
 
FALLOW PERIOD
 
A. DICAMBA*
  (Banvel) 0.25–2.0 lb a.e (0.5–4.0 pt). 24 0
  (Clarity) 1 lb a.e. (2 pt) 24 0
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  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. GLYPHOSATE 0.38–0.5 lb a.i. 4 See label
  (Roundup PowerMax, WeatherMax) 10.8–14.22 oz    
  WSSA MODE-OF-ACTION GROUP NUMBER1: 9
  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).
 
C. PARAQUAT* 0.5 lb a.i. 12 NA
  (Gramoxone SL 2.0) 2 pt    
  WSSA MODE-OF-ACTION GROUP NUMBER1: 22
  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.
 
D. PYRAFLUFEN-ETHYL
  (ET) 0.5-2 oz/acre 12 0
  WSSA MODE-OF-ACTION GROUP NUMBER1: 14
  COMMENTS: A contact herbicide effective at very low use rates on many broadleaves. Combining pyraflufen-ethyl with phenoxy herbicides or dicamba broadens the weed spectrum controlled.
 
PREPLANT or PREEMERGENCE TO CROP
 
A. GLYPHOSATE 0.38–0.5 lb a.i.    
  (Roundup PowerMax, WeatherMax) 10.8–14.22 oz 4 See label
  WSSA MODE-OF-ACTION GROUP NUMBER1: 9
  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).
 
B. PARAQUAT* 0.49–1 lb a.i.    
  (Gramoxone SL 2.0) 2–4 pt 12 0
  WSSA MODE-OF-ACTION GROUP NUMBER1: 22
  COMMENTS: For use on barley and wheat only. Rate varies with weed size; use lower rate on weeds
1 to 3 inches tall. Do not graze livestock in treated areas or harvest for forage hay.
 
POSTPLANT – WHEAT
Before Weeds Emerge
 
A. PENDIMETHALIN
  (Prowl H2O) 1.5-3 pt/acre 24 60
  WSSA MODE-OF-ACTION GROUP NUMBER1: 3
  COMMENTS: Emerged weeds will not be controlled.
 
POSTPLANT – WHEAT
After Weeds Emerge
 
A. 2,4-D AMINE* 0.31–0.87 lb a.i. (10.44-29.30 oz) 48 See comments
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  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.
 
B. BROMOXYNIL 0.25lb a.i.    
  (Buctril) 1 pt 24 0
  WSSA MODE-OF-ACTION GROUP NUMBER1: 6
  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 has a dense canopy.
 
C. CARFENTRAZONE
  (Shark EW) Label rates 12 7 - forage
  WSSA MODE-OF-ACTION GROUP NUMBER1: 14
  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. Can cause necrosis and temporary stunting.
 
D. CHLORSULFURON 0.008–0.015 lb a.i. 4 45
  (Glean) 0.006-0.011 oz    
  WSSA MODE-OF-ACTION GROUP NUMBER1: 2
  COMMENTS: Apply to crop from 2 to 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 per 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 to 3 years or more.
 
E. CLOPYRALID
  (Stinger) Label rates 12 See comments
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  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.
 
F. DICAMBA* 0.062–0.125 lb a.i.    
  (Banvel, Clarity) 2–4 oz 24 7
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  COMMENTS: Apply when crop has 2 to 3 leaves (before well-tillered) and weeds have 2 to 3 leaves. Do not apply by air if sensitive crops are nearby. Usually mixed with MCPA or carfentrazone. Injury increases when mixed with 2,4-D or bromoxynil herbicides. May cause grain to temporarily flatten. Use is restricted in some counties.
 
G. FENOXAPROP
  (Puma 1EC) Label rates 24 70
  WSSA MODE-OF-ACTION GROUP NUMBER1: 1
  COMMENTS: For use on wheat and barley; apply to the crop from second leaf up to 70 days before harvest. May be tank mixed with bromoxynil. Rainfall within 1 hour of application will reduce weed control.
 
H. MCPA AMINE* 0.23–0.46 lb a.i.    
    0.5–1 pt 48 0
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  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.
 
I. MESOSULFURON
  (Osprey) 4.75 oz 4 See comments
  WSSA MODE-OF-ACTION GROUP NUMBER1: 2
  COMMENTS: For control of annual grass and broadleaf weeds in wheat grown over the winter. 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. Often causes temporary yellowing that typically goes away in two weeks. Wheat injury can be severe if a freeze occurs following an application. Pre-harvest interval is 30 days for wheat or triticale forage, and 60 days for hay, grain, and straw. See label for plantback restrictions.
 
J. PINOXADEN
  (Axial XL) 16.4 fl oz 48 See comments
  WSSA MODE-OF-ACTION GROUP NUMBER1: 1
  COMMENTS: Selective grass herbicide. Pre-harvest interval is 30 days for silage, and 60 days for grain and straw.
 
K. PYRAFLUFEN-ETHYL
  (ET) 0.5–2 oz/acre 12 See comments
  WSSA MODE-OF-ACTION GROUP NUMBER1: 14
  COMMENTS: A contact herbicide effective at very low use rates on many broadleaves. Combining pyraflufen-ethyl with phenoxy herbicides or dicamba broadens the weed spectrum controlled. Do not harvest wheat hay within 21 days after treatment. Wheat may be harvested for grain 60 days after treatment.
 
L. TRIBENURON METHYL 0.25–0.50 oz 12 45
  (Express)
  WSSA MODE-OF-ACTION GROUP NUMBER1: 2
  COMMENTS: Can be used after weed emergence. Do not exceed more than two applications per season (combined maximum 0.50 oz/A). Should be applied as tank mixture with other fallow herbicide. Apply after 2-leaf stage, but before development of flag leaf.
 
POSTPLANT – BARLEY
After Weeds Emerge
 
A. 2,4-D AMINE* 0.26–0.95 lb a.i. (8.75-32.0 oz) 48 See comments
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  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; PHI is 14 days. Do not feed treated straw to livestock.
 
B. CARFENTRAZONE-ETHYL
  (Shark EW) Label rates 12 7 - forage
  WSSA MODE-OF-ACTION GROUP NUMBER1: 14
  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.
 
C. CHLORSULFURON 0.008–0.015 lb a.i. 4 45
  (Glean) 0.006-0.011 oz    
  WSSA MODE-OF-ACTION GROUP NUMBER1: 2
  COMMENTS: Apply to crop from 2 to 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 per 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 to 3 years or more.
 
D. CLOPYRALID
  (Stinger) Label rates 12 See comments
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  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.
 
E. FENOXAPROP-P-ETHYL
  (Puma) 1EC Label rates 24 70
  WSSA MODE-OF-ACTION GROUP NUMBER1: 1
  COMMENTS: For use on wheat and barley; apply to the crop from second leaf up to 70 days before harvest. May be tank mixed with bromoxymil. Rainfall within 1 hour of application will reduce weed control.
 
F. MCPA AMINE* 0.23–0.46 lb a.i.    
    0.5–1 pt 48 0
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  COMMENTS: Apply to crop from 3- to 5-leaf stage to early jointing. Restricted use between Feb 15 and Oct 15.
G. PINOXADEN
  (Axial XL) 16.4 fl oz 48 See comments
  WSSA MODE-OF-ACTION GROUP NUMBER1: 1
  COMMENTS: Selective grass herbicide. Pre-harvest interval is 30 days for silage, and 60 days for grain and straw.
 
H. TRIBENURON-METHYL 0.25–0.50 oz 12 45
  (Express)      
  WSSA MODE-OF-ACTION GROUP NUMBER1: 2
  COMMENTS: Can be used after weed emergence. Do not exceed more than two applications per season (combined maximum 0.50 oz/A). Should be applied as tank mixture with other fallow herbicide. Apply after 2-leaf stage, but before development of flag leaf.
 
POSTPLANT – OATS
After Weeds Emerge
 
A. BROMOXYNIL 0.25 lb a.i.    
  (Buctril) 1 pt 24 0
  WSSA MODE-OF-ACTION GROUP NUMBER1: 6
  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. Rates over 0.5 pint/acre may increase oat injury. Injury is greater during moisture stress and freezing temperatures. Adding foliar nitrogen will increase injury.
 
B. CARFENTRAZONE
  (Shark EW) Label rates 12 7 - forage
  WSSA MODE-OF-ACTION GROUP NUMBER1: 14
  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.
 
C. CHLORSULFURON 0.008–0.015 lb a.i.    
  (Glean) 0.006-0.011 oz 4 45
  WSSA MODE-OF-ACTION GROUP NUMBER1: 2
  COMMENTS: Apply to crop from 2 to 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 per 18-month period. Must be tank mixed with dicamba or bromoxynil if weeds are present at application time.
 
D. CLOPYRALID
  (Stinger) Label rates 12 See comments
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  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.
 
E. DICAMBA* 0.062–0.125 lb a.i.    
  (Banvel, Clarity) 2–4 oz 24 7
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  COMMENTS: Apply to oats before 5-leaf stage and weeds have 2 to 3 leaves. Do not apply by air if sensitive crops are nearby. When mixed with MCPA and bromoxynil injury is more likely to occur.
 
F. MCPA AMINE* 0.23–0.46 lb a.i.    
    0.5–1 pt 48 0
  WSSA MODE-OF-ACTION GROUP NUMBER1: 4
  COMMENTS: Apply to oats from 5-leaf stage to early jointing. Restricted use between Feb 15 and Oct 15.
 
Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) 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.

[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
S. D. Wright, UC Cooperative Extension, Tulare County
L. F. Jackson, Agronomy, UC Davis

Acknowledgment for contributions to Weeds:
C. E. Bell, UC Cooperative Extension, San Diego County
H. L. Carlson, UC Cooperative Extension, Siskiyou County
D. W. Cudney, Botany and Plant Sciences, UC Riverside
J. E. Hill, Agronomy, UC Davis
M. J. Smith, UC Cooperative Extension, San Luis Obispo County
R. N. Vargas, UC Cooperative Extension, Madera County

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