Agriculture: Rice Pest Management Guidelines

Herbicide Treatment Table

  Common name Amount per acre REI‡ PHI‡
(Example trade name) (hours) (days)
Not all registered pesticides are listed. The following are listed alphabetically. When choosing a pesticide, consider information relating to environmental impact, resistance management, the pesticide's properties, and application timing. Tank mixes may be necessary to achieve desired control; see the Susceptibility of Weeds to Herbicide Control for information on specific weed control. Always read the label of the product being used.
 
SINGLE HERBICIDE APPLICATIONS (AFTER PLANTING)
A. BENSULFURON 0.06 lb a.i.    
  (Londax) 1.66 oz 24 80
  RESISTANCE: some populations of smallflower umbrella sedge, ricefield bulrush, California arrowhead, redstem
  RESIDUAL: 35–40
  MODE-OF-ACTION GROUP NUMBER1: 2 (sulfonylurea: ALS inhibitor)
  APPLICATION TIMING: early: 1–3 lsr, later: 4 lsr to 1–2 til
  MODE OF APPLICATION: early: into water, later: water receded to 70% exposed foliage
  COMMENTS: Provides grass suppression while controlling numerous broadleaves, including ducksalad. Provides residual activity up to 40 days and can be tank-mixed with several other herbicides to increase weed control spectrum. Apply into static water to prevent movement of the herbicide and loss of weed control. Areas most likely to lose weed control following the application of this herbicide are in uppermost basins or around rice boxes where water has been allowed to flow. Water depth is less important than holding the water static. If water depth subsides before 5 days, water can be added but some loss of weed control may occur where water movement is greatest. If rice is poorly rooted because of wind or other damage, allow it ample time to anchor before using bensulfuron, otherwise rice root development may be delayed. May be applied as a spray solution or as a direct dry flowable product. Sprays are applied with conventional booms and the dry flowable formulation by precision low volume metering equipment, both by aircraft. Do not use on wild rice.
 
B. BISPYRIBAC-SODIUM 0.03–0.04 lb a.i.    
  (Regiment CA) 0.53–0.8 oz 12 0
  RESISTANCE: some populations of barnyardgrass, watergrasses, ricefield bulrush, California Arrowhead
  RESIDUAL: 0 days
  MODE-OF-ACTION GROUP NUMBER1: 2 (pyrimidinyl-thiobenzoates: ALS inhibitor)
  APPLICATION TIMING: early: 4 lsr, later: to 1st til
  MODE OF APPLICATION: early: drained but wet field, later: water receded to 70% exposed foliage
  COMMENTS: Controls wide-spectrum, including watergrass, ricefield bulrush, California arrowhead, ducksalad, and waterhyssop, but not smallflower umbrella sedge. High rate is needed for control of resistant late watergrass.
 
C. CARFENTRAZONE-ETHYL 0.1–0.19 lb a.i.    
  (Shark H2O) 4–7.6 oz (see comments) 12 60
  RESISTANCE: no
  RESIDUAL: 5–8 days
  MODE-OF-ACTION GROUP NUMBER1: 14 (triazolinone: inhibits PPO)
  APPLICATION TIMING: 2–4 lsr or 20–45 days postseeding depending on floodwater coverage of weeds
  MODE OF APPLICATION: into water (either when weeds are submerged or 80% of weed foliage exposed)
  COMMENTS: Controls broadleaf weeds and sedges; can be used where bensulfuron (Londax), halosulfuron (Sandea), orthosulfamuron (Strada CA), or propanil resistance occurs. Can be tank-mixed with herbicides that control grasses. Hold the water at a static depth for at least 5 days after application. Once field is flooded, water must be held for at least 23 days after application before water is released. Only ground application allowed in pin-point flooded fields. Direct-dry application or direct-stream application recommended to prevent drift to other crops. Direct-dry application by fixed wing aircraft registered under two Special Local Needs labels (wild rice: EPA SLN No. CA-05007, other rice: EPA SLN No. CA-020007). Direct stream application by helicopter or ground registered under a Special Local Needs Label (EPA SLN No. CA-020008). Application rate for aerial-applied carfentrazone is 4–7.5 oz for wild rice and 7.5 oz for other rice.
 
D. CLOMAZONE 0.4–0.6 lb a.i.    
  (Cerano 5 MEG) 8–12 lb (see comments) 12 120
  RESISTANCE: some populations of barnyardgrass, watergrasses, sprangletop
  RESIDUAL: 5 days in water
  MODE OF ACTION GROUP NUMBER1: 13 (isoxazolidinone: carotenoid biosynthesis inhibitor)
  APPLICATION TIMING: preseeding to l lsr
  MODE OF APPLICATION: into water
  COMMENTS: Different mode of action from other herbicides currently registered for use in rice; controls watergrass populations that are resistant to other herbicides and helps prevent the increase of such resistance. Reduced rate of 8 lb per acre may be used to control sprangletop and in certain soil types (see label for more information). May cause cosmetic injury to rice (bleaching, stunting, reduction in stand density), but no significant yield reductions have been observed.
 
E. COPPER SULFATE PENTAHYDRATE#      
  (Copper Sulfate Crystals)# Freshwater algae: 6.8–13.6 lb
Other algae: 2.72–5.44 lb
48 0
  APPLICATION TIMING: see comments
  MODE OF APPLICATION: into water
  COMMENTS: Apply higher rate in deeper water (6-inch depth or greater). Best results are obtained when very fine granules or crystals are dropped into the floodwater; or when the copper sulfate is dissolved in water and sprayed. Apply treatments as the algae forms on the soil surface and organic matter and air pockets are beginning to form under the algae (causing it to start to rise to the surface of the water and float). Once the algae has floated to the surface and formed large mats, control is very difficult. Fields irrigated from wells often have algae problems and should be watched carefully. Hard water (excess carbonate) will tend to negate the effects of copper sulfate. Copper sulfate rates of 6.8 to 13.6 lb with 48-hour water-holding period for control of freshwater algae is allowed under a Special Local Needs label (EPA SLN No. CA-130013), which expires December 31, 2023.
 
F. CYHALOFOP 0.24–0.27 lb a.i.    
  (Clincher CA) 13–15 fl oz 12 60
  RESISTANCE: some populations of barnyardgrass, watergrasses and sprangle top
  RESIDUAL: 0 days
  MODE-OF-ACTION GROUP NUMBER1: 1 (aryloxyphenoxy-propionate: ACCase inhibitors)
  APPLICATION TIMING: early: 1–2 lsr; later: 3 lsr to mid til
  MODE OF APPLICATION: early: drained field, later: water receded to 70% exposed foliage
  COMMENTS: Used for grass control in situations where thiobencarb (Abolish/Bolero) cannot be used because of delayed phytotoxicity syndrome. Effective on susceptible watergrass and sprangletop. Safe to rice crop. Ground application is required in some areas because of sensitivity of fruit trees. Use low rate on grasses that have up to four leaves, before tillering. Use high rate on tillered grasses.
 
G. HALOSULFURON 0.031–0.062 lb a.i.    
  (Sandea) 0.67–1.33 oz 12 69
  RESISTANCE: some populations of smallflower umbrella sedge, ricefield bulrush, California arrowhead, redstem
  RESIDUAL: 35–40 days
  MODE OF ACTION GROUP NUMBER1: 2 (sulfonylurea: ALS inhibitor)
  APPLICATION TIMING: 1–2 (dry broadcast) or 3–5 lsr (foliar application)
  MODE OF APPLICATION: into water, foliar spray (70 to 80% of weed foliage exposed), or dry broadcast
  COMMENTS: Halosulfuron controls broadleaf and sedge weeds. It can cause rice stunting; however, plants usually recover from these symptoms.
 
H. ORTHOSULFAMURON 0.053–0.065 lb a.i.    
  (Strada CA) 1.7–2.1 oz 12 0
  RESISTANCE: some populations of smallflower umbrella sedge, ricefield bulrush, California arrowhead, redstem
  RESIDUAL: 25 days
  MODE-OF-ACTION GROUP NUMBER1: 2 (sulfonylurea: ALS inhibitor)
  APPLICATION TIMING: 2 to 4 lsr
  MODE OF APPLICATION: foliar, early postemergence to preflood (dry-seeded rice), early postemergence or middle-to-late postemergence (at least 70% of weed foliage exposed)
  COMMENTS: Orthosulfamuron controls broadleaf and sedge weeds. It is particularly effective on Monochoria. It can cause some rice stunting; however, plants usually recover from these symptoms.
 
I. PENDIMETHALIN 0.71–0.95 lb a.i.
  (Prowl H2O) 1.5–2 pt (see comments) 24 0
  RESISTANCE: no
  RESIDUAL: 20 days (dry soil); 5 days (water)
  MODE-OF-ACTION GROUP NUMBER1: 3 (dinitroaniline: microtubule assembly inhibitor)
  APPLICATION TIMING: 0 or 4–6 lsr
  MODE OF APPLICATION: drained field (dry top layer of soil)
  COMMENTS: Prowl H2O is generally used in direct-seeded rice. It can be used before or after the initial flush of water, but apply it prior to the emergence weeds. Its efficacy is during the germination period of seeds, and therefore it will not control established weeds. Rice is relatively tolerant to Prowl H2O once it has imbibed sufficient moisture for germination. Activity of Prowl H2O diminishes with additional water flushes and degrades quickly with flooding. See label for specific rates based on soil type. Not for use on grain-drilled, dry-seeded rice in California.
 
J. PENOXSULAM 0.036–0.044 lb a.i. (Granite GR)    
    0.031–0.043 lb a.i. (Granite SC)    
  (Granite GR) 15–18.5 lb 12 60
  (Granite SC) 2–2.8 fl oz 12 60
  RESISTANCE: some populations of barnyardgrass and watergrasses, ricefield bulrush, redstem, and California arrowhead
  RESIDUAL: 35–40 days
  MODE OF ACTION GROUP NUMBER1: 2 (triazolopyrimidine: ALS inhibitor)
  APPLICATION TIMING: Granite GR: after 2.5 lsr; Granite SC: 4 lsr to 60 days before harvest
  MODE OF APPLICATION: into water or foliar
  COMMENTS: Granite GR (granular formulation) will control many weed species. It tends to stunt early root growth of rice. Granite SC (liquid suspension formulation) is generally applied on foliage at later stages of rice growth when floodwater is dropped for good exposure of weeds. Since Granite SC is usually applied later, it causes less phytotoxicity to the rice plant. Do not use on wild rice.
 
K. PROPANIL* 3–6 lb a.i.    
  (Stam 80 EDF-CA, SuperWham! 80DF-CA) 3.75–7.5 lb 24 60
  RESISTANCE: Some populations of barnyardgrass, early and late watergrass, bulrush and smallflower umbrellasedge
  RESIDUAL: 0 days
  MODE OF ACTION GROUP NUMBER1: 7 (amide: photosystem II inhibitor)
  APPLICATION TIMING: Stam 80EDF = early: from 3 lsr; SuperWham! 80DF = later: to mid-tiller
  MODE OF APPLICATION: Stam 80EDF = early: drained field; SuperWham! 80DF = later: water receded to 70% exposed foliage
  COMMENTS: A contact herbicide that controls an array of weeds such as watergrass, barnyardgrass, sedges, while suppressing sprangletop and other broadleaf weeds. Early treatments control watergrass more effectively; however, application generally must be delayed 35 to 50 days after seeding to control emerged broadleaf weeds. This allows adequate time for broadleaf weeds to develop sufficient foliage. If earlier watergrass control is desired under these conditions, a postplant treatment of thiobencarb is recommended. Can be applied by either ground or air in 10 to 15 gallons of water. Use higher volume to get better coverage and control of large grasses or dense weed populations. Use the low rate on young watergrass (30–35 days after seeding) in very shallow water to assure good coverage of the weed. Use the high rate when most watergrass is 6 to 9 inches above the water. Leaf injury (tip burn) may occur on rice when the temperature is above 85° to 90°F at the time of the application. Do not use propanil within 14 days of an application of a carbamate (such as carbaryl) or organophosphate (such as malathion). (Exception: Low dosages of insecticide as used for mosquito larva control in rice fields may be applied 5 days before or after application of propanil.)
 
L. THIOBENCARB* 3–4 lb a.i. (Abolish)    
    3.495 lb a.i. (Bolero Ultramax)  
  (Abolish 8EC) 3–4 pt 7 days 0
  (Bolero Ultramax) 23.3 lb 7 days 0
  RESISTANCE: some populations of barnyardgrass, watergrasses and smallflower umbrella sedge
  RESIDUAL: 25 days
  MODE OF ACTION GROUP NUMBER1: 8 (thiocarbamate: inhibits lipid synthesis)
  APPLICATION TIMING: Abolish 8EC = 2–3 lsr; Bolero Ultramax = 2 lsr
  MODE OF APPLICATION: Abolish 8EC = drained field; Bolero Ultramax = applied in water
  COMMENTS: Mostly used for grass control but also provides some control of smallflower umbrella sedge and selected broadleaf weeds. Abolish may be applied preflood to fields that are immediately flooded, however, the effective residual period after flooding is considerably short. Both Abolish 8EC and Bolero Ultramax may be applied after the crop has emerged, but the window for rice safety and weed control is very narrow. Because timing of thiobencarb to weeds and rice is so important, the following situations should be avoided: fields that take longer than 5 days to flood and fields with greater than 0.2 foot fall to avoid deep-water stress. Use caution when using dry coated seed because it delays germination, which narrows the application window by allowing watergrass to become too large while rice is still in the sensitive stage. Make postplant application when 70% of the rice seedlings have reached the 2-leaf stage. Rice is very sensitive to these formulations at the one-leaf stage and may be severely injured if it is applied too early. Thiobencarb provides residual activity of about 25 days. It will not be effective on watergrass or barnyardgrass beyond the 3-leaf stage. Do not use within 14 days of an application of a carbamate (such as carbaryl) or organophosphate (such as malathion). Note: Check with agricultural commissioner for water-holding requirements following all thiobencarb applications. Do not make more than one application per year.
 
M. TRICLOPYR 0.25–0.375 lb a.e.    
  (Grandstand CA) 0.67–1 pt 48 60
  RESISTANCE: no
  RESIDUAL: 0 days
  MODE OF ACTION GROUP NUMBER1: 4 (pyridine carboxylic acid: auxin-type herbicide)
  APPLICATION TIMING: early: from 1st til, later: to max. til
  MODE OF APPLICATION: early: drained field, later: water receded to 70% exposed foliage
  COMMENTS: Used for ricefield bulrush, redstem, and waterhyssop; is not effective for grass control. Apply by air or ground; weeds should be actively growing at time of treatment and well above the water surface. A translocated herbicide that requires that only 70% of the weed foliage be exposed for adequate spray coverage. Consult your county agricultural commissioner for current water management restrictions. If the water level is dropped to expose weeds before treatment, do not raise the water level for at least 48 hours after application. Do not make more than two applications per season and allow at least 20 days between applications. May be tank mixed with propanil. Do not allow drift to sensitive crops. See label for other restrictions.
 
  HERBICIDE TANK MIXES and PREMIXES
  Note: If resistance to barnyardgrass or watergrasses is suspected in a field, avoid combinations or sequences of herbicides with mode-of-action group numbers 1, 2, 8, and 13 (1 = cyhalofop [Clincher CA]; 2 = penoxsulam [Granite], bensulfuron [Londax], bispyribac [Regiment CA], halosulfuron [Sandea]; 8= thiobencarb [Abolish 8EC, Bolero]; and 13 = clomazone [Cerano 5 MEG]). For all tank mixes, observe all directions for use on all labels, and employ the most restrictive limits and precautions. Never exceed the maximum a.i. on any label.
 
A. BENZOBICYCLONE/HALOSULFURON 0.23–0.27 lb a.i. (benzobycyclon)    
    0.019–0.058 lb a.i. (halosulfuron methyl)    
  (Butte) 7.5–9 lb 12 82
  RESISTANCE: No resistant weeds for benzobicyclon for were reported in California.
  RESIDUAL: Benzobicyclon = 14 days, halosulfuron = 30 days
  MODE-OF-ACTION GROUP NUMBERS1: 27 (Inhibition of 4-hydroxyphenyl-pyruvate-dioxygenase, HPPD) plus 2 (sulfonylurea: ALS inhibitor)
  MODE OF APPLICATION: Benzobicyclon, the major component of the formulation, is a pro-herbicide and the formulated product must be applied into flooded fields to allow for conversion to the herbicidal active ingredient. Application to dry soils will provide minimal weed control. Average water depth at application should be a minimum of 4 inches with no bare soil.
  APPLICATION TIMING: Apply at day of seeding to 4 true leaf rice, however, weed control efficacy can be significantly reduced at 4 true leaf rice stage
  COMMENTS: Butte can only be used in rice that will be followed by rice the following year. Do not make more than one application or apply more than 9 lb of Butte (0.27 lb ai Benzobicyclon) and (0.058 lb Halosulfuron-methyl) per annual growing season. Minimum water hold period for Butte is twenty (20) days.
 
B. BISPYRIBAC-SODIUM 0.0265–0.0335 lb a.i    
  (Regiment CA) 0.53–0.67 oz 12 0
  ...PLUS...
  CARFENTRAZONE-ETHYL 0.19 lb a.i.    
  (Shark H2O) 7.6 oz 12 60
  RESISTANCE FOR TANK MIX: some populations of barnyardgrass and watergrasses
  RESIDUAL: Regiment CA = 0 days; Shark H2O = 5–8 days
  MODE-OF-ACTION GROUP NUMBERS1: 2 (pyrimidinyl-thiobenzoates: ALS inhibitor) plus 14 (triazolinone: inhibits PPO)
  APPLICATION TIMING: Regiment CA = 4–5 lsr; Shark H2O = 4-5 lsr
  MODE OF APPLICATION: Regiment CA = 70% of weed foliage exposed; Shark H2O = flooded field or water lowered to reveal 80% of weed foliage.
 
C. BISPYRIBAC-SODIUM 0.0265–0.0335 lb a.i.    
  (Regiment CA) 0.53–0.67 oz 12 0
  ...PLUS...
  THIOBENCARB* 2–3 lb a.i.    
  (Abolish 8EC) 2–3 pt 7 days 0
  RESISTANCE FOR TANK MIX: some populations of barnyardgrass, watergrasses, ricefield bulrush, California arrowhead
  RESIDUAL: Regiment CA= 0 days; Abolish 8EC = 20–25 days
  MODE-OF-ACTION GROUP NUMBERS1: 2 (pyrimidinyl-thiobenzoates: ALS inhibitor) plus 8 (thiocarbamate: inhibit lipid synthesis)
  APPLICATION TIMING: Regiment CA = 5–6 lsr; Abolish 8EC = 5–6 lsr
  MODE OF APPLICATION: Regiment CA = drained (but wet) field; Abolish 8EC = water level lowered to reveal 70% of weed foliage
 
D. PROPANIL* 4–6 lb a.i.    
  (Stam 80 EDF-CA, SuperWham! 80DF-CA) 5–7.5 lb 24 60
  ...PLUS...
  PENOXSULAM 0.036 lb a.i.    
  (Granite SC) 2.3 fl oz 12 60
  RESISTANCE FOR TANK MIX: Some populations of barnyardgrass, watergrass, sprangletop, smallflower umbrella sedge, ricefield bulrush
  RESIDUAL: Stam 80EDF, SuperWham! = 0 days; Granite SC = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 7 (amide: photosystem II inhibitor) plus 2 (triazolopyrimidine: ALS inhibitor)
  APPLICATION TIMING: Stam 80EDF, SuperWham! 80DF-CA = 4–6 lsr; Granite SC = 4–6 lsr
  MODE OF APPLICATION: Stam 80EDF = drained field, SuperWham! 80DF-CA = drained field; Granite SC = partially drained field (at least 70% of weed foliage exposed)
 
E. PROPANIL* 3 lb a.i.    
  (Stam 80 EDF-CA, SuperWham! 80DF-CA) 3.75 lb 24 60
  ...PLUS...
  THIOBENCARB 3 lb a.i.    
  (Abolish 8EC) 3 pt 7 days 0
  RESISTANCE FOR TANK MIX: Some populations of barnyardgrass, watergrass, sprangletop, smallflower umbrella sedge, ricefield bulrush
  RESIDUAL: Stam 80EDF-CA, SuperWham! 80DF-CA= 0 days; Abolish 8EC= 20-25 days
  MODE-OF-ACTION GROUP NUMBERS1: 7 (amide: photosystem II inhibitor) plus 8 (thiocarbamate: inhibit lipid synthesis)
  APPLICATION TIMING: Stam 80EDF-CA, SuperWham! 80DF-CA= 2–3 lsr; Abolish 8EC = 2–3 lsr
  MODE OF APPLICATION: Stam 80EDF = drained field, SuperWham! 80DF-CA= drained field; Abolish 8 EC = drained field
  COMMENTS: For Abolish, application rate and mode of application varies based on field type, application timing, and soil type.
 
F. PROPANIL*/HALOSULFURON 3–6 lb a.i. (propanil)    
    0.023–0.046 lb a.i. (halosulfuron methyl)    
  (RiceEdge 60DF) 5–10 lb 24 69
  RESISTANCE: Some populations of barnyardgrass, watergrass, sprangletop, smallflower umbrella sedge, ricefield bulrush
  RESIDUAL: Propanil = 0, halosulfuron = 30
  MODE-OF-ACTION GROUP NUMBERS1: 7 (amide: photosystem II inhibitor) plus 2 (sulfonylurea: ALS inhibitor)
  MODE OF APPLICATION: drain field before application and bring water back 48 hours after application.
  APPLICATION TIMING: 1 to 3 lsr
 
G. THIOBENCARB/IMAZOSULFURON 3–3.5 lb a.i. (thiobencarb)    
    0.013–0.015 lb a.i. (imazosulfuron)    
  (League MVP) 30–35lb 12 0
  RESISTANCE: some populations of barnyardgrass, watergrasses and smallflower umbrella sedge
  RESIDUAL: thiobencarb = 20–25, imazosulfuron = 25
  MODE-OF-ACTION GROUP NUMBERS1: 8 (thiocarbamate: inhibit lipid synthesis) plus 2 (pyrimidinyl-thiobenzoates: ALS inhibitor)
  MODE OF APPLICATION: after flooding
  APPLICATION TIMING: 2 lsr
  COMMENTS: 12-hour REI allowed under a California supplemental label, which expires August 31, 2021.
 
  HERBICIDE SEQUENCES WITH BISPYRIBAC-SODIUM (Regiment)
A. BISPYRIBAC-SODIUM 0.0335–0.04 lb a.i    
  (Regiment CA) 0.67–0.8 oz 12 0
  ...FOLLOWED BY...
  PROPANIL* 6 lb a.i.    
  (Stam 80 EDF-CA, SuperWHAM 80 DF-CA) 7.5 lb 24 60
  RESISTANCE FOR SEQUENCE: some populations of barnyardgrass, watergrasses, ricefield bulrush, smallflower umbrella sedge, only suppression of California arrowhead in a resistant population
  RESIDUAL: Regiment CA = 0 days; Stam 80 EDF, SuperWham! 80DF-CA = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 2 (pyrimidinyl-thiobenzoates: ALS inhibitor) plus 7 (amide: photosystem II inhibitor)
  APPLICATION TIMING: Regiment CA = 4 lsr–1 til; Stam 80EDF, SuperWham! 80DF-CA = 2–3 til
  MODE OF APPLICATION: Regiment CA = preflood to wet soil (dry-seeded), drained field (pinpoint flood), or 70% of weed foliage exposed (postflood); Stam 80EDF = drained field, SuperWham! 80DF-CA = 70% foliage exposed
  COMMENTS: Resistance not yet a problem with propanil.
 
  HERBICIDE SEQUENCES WITH CLOMAZONE (Cerano 5 MEG)
A. CLOMAZONE 0.4–0.6 lb a.i.    
  (Cerano 5 MEG) 8–12 lb 12 120
  COMMENTS: Used for grass control in situations where thiobencarb (Abolish/Bolero) cannot be used because of delayed phytotoxicity syndrome. Effective on susceptible watergrass and sprangletop. Safe to rice crop. Ground application is required in some areas because of sensitivity of fruit trees.
  ...FOLLOWED BY...
  BENSULFURON 0.06 lb    
  (Londax) 1.67 oz 24 80
  RESISTANCE FOR SEQUENCE: some populations of barnyardgrass, watergrass, poor control in Londax-resistant populations of smallflower umbrella sedge, ricefield bulrush, California arrowhead, redstem
  RESIDUAL: Cerano 5 MEG= 5 days in water; Londax = 35–40 days
  MODE-OF-ACTION GROUP NUMBERS1: 13 (isoxazolidinone: carotenoid biosynthesis inhibitor) followed by 2 (sulfonylurea: ALS inhibitor)
  APPLICATION TIMING: Cerano 5 MEG = Preseed to 1 lsr; Londax = 1–3 lsr
  MODE OF APPLICATION: Cerano 5 MEG = into water; Londax = into water
  COMMENTS: Apply into static water to prevent movement of the herbicide and loss of weed control. Areas most likely to lose weed control following the application of this herbicide are in uppermost basins or around rice boxes where water has been allowed to flow. Water depth is less important than holding the water static. If water depth subsides before 5 days, water can be added but some loss of weed control may occur where water movement is greatest. If rice is poorly rooted because of wind or other damage, allow it ample time to anchor before using, otherwise rice root development may be delayed. Do not use on wild rice.
  ...OR...
  BISPYRIBAC-SODIUM 0.0335–0.04 lb a.i    
  (Regiment CA) 0.67–0.8 oz 12 0
  RESISTANCE FOR SEQUENCE: some populations of barnyardgrass, watergrass, sprangle top, poor control in Regiment-resistant populations of ricefield bulrush and California arrowhead
  RESIDUAL: Cerano 5 MEG = 5 days in water; Regiment CA = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 13 (isoxazolidinone: carotenoid biosynthesis inhibitor) followed by 2 (pyrimidinyl-thiobenzoates: ALS inhibitor)
  APPLICATION TIMING: Cerano 5 MEG = Preseed to 1 lsr; Regiment CA = 2–3 til
  MODE OF APPLICATION: Cerano 5 MEG = into water; Regiment CA = 70% foliage exposed
  COMMENTS: High rate of bispyribac-sodium could cause phytotoxicity to rice after an application of clomazone.
  ...OR...
  CARFENTRAZONE-ETHYL 0.19 lb a.i.    
  (Shark H2O) 7.6 oz (see comments) 12 60
  RESISTANCE FOR SEQUENCE: some populations of watergrass, barnyardgrass, sprangle top
  RESIDUAL: Cerano 5 MEG = 5 days in water; Shark H2O = 5–8 days
  MODE-OF-ACTION GROUP NUMBERS1: 13 (isoxazolidinone: carotenoid biosynthesis inhibitor) followed by 14 (triazolinone: inhibits PPO)
  APPLICATION TIMING: Cerano 5 MEG = Preseed to 1 lsr; Shark H2O = 2–3 lsr
  MODE OF APPLICATION: Cerano 5 MEG = into water; Shark H2O = into water (when weeds are submerged or when 80% of weed foliage is exposed)
  COMMENTS: Controls broadleaf weeds; can be used where bensulfuron (Londax) resistance occurs. Can be tank mixed with herbicides that control grasses. Hold the water at a static depth for at least 5 days after application. Once field is flooded, water must be held for at least 23 days after application before water is released. Only ground application allowed in pin-point flooded fields. Direct-dry application or direct-stream application recommended preventing drift to other crops. Direct-dry application and direct stream application by aircraft is registered under supplemental labels (for DDA by fixed wing aircraft in wild rice, EPA SLN No. CA-050007; for DDA in other rice, EPA SLN No. CA-020007; for DSA in other rice, EPA SLN No. CA-020008). Application rate for aerial-applied carfentrazone is 4–7.5 oz for wild rice and 7.5 oz for other rice.
  ...OR...
  PROPANIL 6 lb a.i.    
  (Stam 80 EDF-CA, SuperWham! 80DF-CA) 7.5 lb 24 60
  RESISTANCE FOR SEQUENCE: some populations of barnyardgrass, watergrass, sprangle top, ricefield bulrush, smallflower umbrella sedge
  RESIDUAL: Cerano 5 MEG = 5 days in water; Stam 80 EDF, SuperWham! 80DF-CA = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 13 (isoxazolidinone: carotenoid biosynthesis) followed by 7 (amide: photosystem II inhibitor)
  APPLICATION TIMING: Cerano 5 MEG = Preseed to 1 lsr; Stam 80 EDF, SuperWham! 80DF-CA = 1 til to full til
  MODE OF APPLICATION: Cerano 5 MEG = into water; Stam 80 EDF= drained field, SuperWham! 80DF-CA = 70% foliage exposed
  ...OR...
  PROPANIL* (in tank mix with TRICLOPYR) 4 lb a.i.    
  (Stam 80 EDF-CA, SuperWham! 80DF-CA) 5 lb 24 60
  ...PLUS...
  TRICLOPYR 0.25 lb a.e.    
  (Grandstand CA) 0.67 pt 48 60
  RESISTANCE FOR SEQUENCE AND TANK MIX: some populations of barnyardgrass, watergrass, sprangle top
  RESIDUAL: Cerano 5 MEG = 5 days in water; Stam 80 EDF, SuperWham! 80DF-CA= 0 days; Grandstand = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 13 (isoxazolidinone: carotenoid biosynthesis inhibitor) followed by 7 (amide: photosystem II inhibitor) plus 4 (pyridine carboxylic acid)
  APPLICATION TIMING: Cerano 5 MEG = Preseed to 1 lsr; Stam 80 EDF, SuperWham! 80DF-CA= 1til to full til
Grandstand CA = 2–3 lsr (preflood), 3–4 lsr (water-seeded)
  MODE OF APPLICATION: Cerano 5 MEG = into water; Stam 80EDF = drained field, SuperWham! 80DF-CA= 70% foliage exposed, Grandstand CA = preflood, or postflood when emerged weeds are above the floodwater
  COMMENTS: No resistance to propanil.
 
  HERBICIDE SEQUENCES WITH CYHALOFOP (Clincher)
A. CYHALOFOP 0.24–0.28 lb a.i.    
  (Clincher CA) 13–15 fl oz 12 60
  COMMENTS: Different mode of action from other herbicides currently registered for use in rice; controls watergrass populations resistant to other herbicides and helps prevent the increase of these resistant populations. May cause temporary injury to rice (stunting and reduction in stand density), but no significant yield reductions have been observed.
  ...FOLLOWED BY...
  BENSULFURON 0.06 lb a.i.    
  (Londax) 1.67 oz 24 80
  RESISTANCE FOR SEQUENCE: poor control in Clincher-resistant populations of barnyardgrass and watergrasses; or poor control in Londax-resistant populations of smallflower umbrella sedge, ricefield bulrush, California arrowhead, redstem
  RESIDUAL: Clincher CA = 0 days; Londax = 35–40
  MODE-OF-ACTION GROUP NUMBERS1: 1 (aryloxyphenoxy-propionate: ACCase inhibitors) followed by 2 (sulfonylurea: ALS inhibitor)
  APPLICATION TIMING: Clincher CA= 3–6 lsr; Londax = 2–3 til
  MODE OF APPLICATION: Clincher CA= at least 70% of weed foliage exposed; Londax = 70% foliage exposed
  COMMENTS: Apply into static water to prevent movement of the herbicide and loss of weed control. Areas most likely to lose weed control following the application of this herbicide are in uppermost basins or around rice boxes where water has been allowed to flow. Water depth is less important than holding the water static. If water depth subsides before 5 days, water can be added but some loss of weed control may occur where water movement is greatest. If rice is poorly rooted because of wind or other damage, allow it ample time to anchor before using, otherwise rice root development may be delayed. Do not use on wild rice.
  ...OR...
  BISPYRIBAC-SODIUM 0.0335 lb a.i    
  (Regiment CA) 0.67 oz 12 0
  RESISTANCE FOR SEQUENCE: some populations of barnyardgrass, watergrasses, sprangle top, ricefield bulrush, California arrowhead
  RESIDUAL: Clincher CA= 0 days; Regiment CA = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 1 (aryloxyphenoxy-propionate: ACCase inhibitor) followed by 2 (pyrimidinyl-thiobenzoates: ALS inhibitor)
  APPLICATION TIMING: Clincher CA= 3–6 lsr; Regiment CA = 2–3 til
  MODE OF APPLICATION: Clincher CA= 70% of weed foliage exposed, Regiment CA = 70% foliage exposed
  COMMENTS: This sequence will control sprangletop but also can promote watergrass resistance; watch for uncontrolled weeds and be sure to control them.
  ...OR...
  PROPANIL* 6 lb a.i.    
  (Stam 80 EDF-CA, SuperWHAM 8 DF-CA) 7.5 lb 24 60
  RESISTANCE FOR SEQUENCE: some populations of barnyardgrass, watergrasses, sprangle top, ricefield bulrush, smallflower umbrella sedge
  RESIDUAL: Clincher CA = 0 days; Stam 80 EDF, SuperWham! 80DF-CA = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 1 (aryloxyphenoxy-propionate: ACCase inhibitors) followed by 7 (amide: photosystem II inhibitor)
  APPLICATION TIMING: Clincher CA= 3-6 lsr; Stam 80 EDF, SuperWham! 80DF-CA = 2 til to full til
  MODE OF APPLICATION: Clincher CA= at least 70% of weed foliage exposed, Stam 80EDF = drained field, SuperWham! = 70% foliage exposed
  COMMENTS: No resistance to propanil.
 
B. CARFENTRAZONE-ETHYL 0.19 lb a.i.    
  (Shark H2O) 7.6 oz (see comments) 12 60
  COMMENTS: Controls broadleaf weeds; can be used where bensulfuron (Londax) resistance occurs. Can be tank mixed with herbicides that control grasses. Hold the water at a static depth for at least 5 days after application. Once field is flooded, water must be held for at least 23 days after application before water is released. Only ground application allowed in pin-point flooded fields. Direct-dry application or direct-stream application recommended to prevent drift to other crops. Direct-dry application and direct stream application by aircraft is registered under supplemental labels (for DDA by fixed wing aircraft in wild rice, EPA SLN No. CA-050007; for DDA in other rice, EPA SLN No. CA-020007; for DSA in other rice, EPA SLN No. CA-020008). Application rate for aerial-applied carfentrazone is 4 to 7.5 oz for wild rice and 7.5 oz for other rice.
  ...FOLLOWED BY...
  CYHALOFOP 0.27 lb a.i.    
  (Clincher CA) 15 fl oz 12 60
  RESISTANCE FOR SEQUENCE: some populations of barnyardgrass, watergrasses, sprangle
  RESIDUAL: Shark H2O = 5–8 days; Clincher CA = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 14 (triazolinone: inhibits PPO) followed by 1 (aryloxyphenoxy-propionate: ACCase inhibitors)
  APPLICATION TIMING: Shark H2O = 2–4 lsr; Clincher CA = 1–3 til
  MODE OF APPLICATION: Shark H2O = into water (either when weeds submerged or when 80% of weed foliage exposed); Clincher CA = water receded to 70% exposed weed foliage
  COMMENTS: Different mode of action from other herbicides currently registered for use in rice; controls watergrass populations resistant to other herbicides and helps prevent the increase of these resistant populations. May cause cosmetic injury to rice (stunting and reduction in stand density), but no significant yield reductions have been observed.
 
C. CYHALOFOP 0.27 lb a.i.    
  (Clincher CA) 15 fl oz 12 60
  ...FOLLOWED BY...
  PROPANIL 6 lb a.i.    
  (Stam 80 EDF-CA, SuperWham! 80DF-CA) 7.5 lb 24 60
  RESISTANCE FOR SEQUENCE: some populations of barnyardgrass, watergrasses, sprangle top, ricefield bulrush, smallflower umbrella sedge
  RESIDUAL: Clincher CA = 0 days; Stam 80 EDF, SuperWham! 80DF-CA = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 7 (amide: photosystem II inhibitor) followed by 1 (aryloxyphenoxy-propionate: ACCase inhibitors)
  APPLICATION TIMING: Clincher CA = 1–3 til; Stam 80 EDF, SuperWham! 80DF-CA = 5–6 til
  MODE OF APPLICATION: Stam 80EDF = drained field, SuperWham! 80DF-CA = not completely drained field; Clincher CA = 70% foliage exposed
  COMMENTS: Different mode of action from other herbicides currently registered for use in rice; controls watergrass populations resistant to other herbicides and helps prevent the increase of these resistant populations. May cause cosmetic injury to rice (stunting and reduction in stand density), but no significant yield reductions have been observed.
 
  HERBICIDE SEQUENCES WITH PENOXSULAM (Granite)
A. PENOXSULAM 0.036 lb a.i.    
  (Granite GR) 15 lb 12 60
  (Granite SC) 2.3 fl oz 12 60
  ...FOLLOWED BY...
  PROPANIL 6 lb a.i.    
  (Stam 80 EDF-CA, SuperWham! 80DF-CA) 7.5 lb 24 60
  RESISTANCE FOR SEQUENCE: poor control with resistant populations of California arrowhead and redstem
  RESIDUAL: Granite GR = NA; Stam 80 EDF, SuperWham! 80DF-CA = NA
  MODE-OF-ACTION GROUP NUMBERS1: 2 (triazolopyrimidine: ALS inhibitor) followed by 7 (amide: photosystem II inhibitor)
  APPLICATION TIMING: Granite = 3–4 lsr; Stam 80 EDF, SuperWham! 80DF-CA = 1–3 til
  MODE OF APPLICATION: Granite GR = into water; Granite SC = partially drained field (at least 70% of weed foliage exposed); Stam 80 EDF= drained field, SuperWham! 80DF-CA = water receded to 70% exposed foliage
  COMMENTS: If watergrass population is already widely resistant to Granite, this sequence will not protect propanil. Will not control sprangletop unless penoxsulam is mixed with cyhalofop (Clincher CA).
 
  HERBICIDE SEQUENCES WITH THIOBENCARB (Bolero)
A. THIOBENCARB* 3.49 lb a.i.    
  (Bolero Ultramax) 23.3 lb 168
(7 days)
0
  ...FOLLOWED BY...
  BISPYRIBAC-SODIUM 0.0335 lb a.i.    
  (Regiment CA) 0.67 oz 12 0
  RESISTANCE FOR SEQUENCE: some populations of barnyardgrass, watergrasses, ricefield bulrush, California Arrowhead, only suppression of redstem in a resistant population.
  RESIDUAL: Bolero Ultramax = 20-25 days; Regiment CA = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 8 (thiocarbamate: inhibit lipid synthesis) followed by 2 (pyrimidinyl-thiobenzoates: ALS inhibitor)
  APPLICATION TIMING: Bolero Ultramax = 2 lsr; Regiment CA = 4 lsr–til
  MODE OF APPLICATION: Bolero Ultramax = into water; Regiment CA = water receded to 70% exposed foliage
  ...OR...
  PROPANIL* 6 lb a.i.    
  (Stam 80EDF CA, SuperWham! 80DF-CA) 7.5 lb 24 60
  RESISTANCE FOR SEQUENCE: some populations of barnyardgrass, watergrasses, ricefield bulrush, California arrowhead
  RESIDUAL: Bolero Ultramax = 20-25 days; Stam 80EDF, SuperWham! 80DF-CA = 0 days
  MODE-OF-ACTION GROUP NUMBERS1: 8 (thiocarbamate: inhibit lipid synthesis) followed by 7 (amide: photosystem II inhibitor)
  APPLICATION TIMING: Bolero Ultramax = 2 lsr; Stam 80EDF, SuperWham! 80DF-CA = 1–3 til
  MODE OF APPLICATION: Bolero Ultramax = into water; Stam 80EDF = drained field, SuperWham! 80DF-CA = water receded to 70% exposed foliage
  COMMENTS: If the populations of barnyardgrass and watergrasses are already widely resistant to Bolero, this sequence will not protect propanil from resistance development. Broad-spectrum and useful for sprangletop.
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 (PHI) is the number of days from treatment to harvest. In some cases, the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
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.
* Permit required from county agricultural commissioner for purchase or use.
lsr Leaf stage of rice
til Tillering stage
NA Not applicable
Text Updated: 06/19