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2008 North Dakota Weed Control GuideW-253, January 2008 D1. Soybean is a poor competitor with weeds when cool soil temperatures cause slow germination and growth but competes effectively in warm soils when germination and growth are rapid. Management practices such as thorough seedbed preparation, adequate soil fertility, choice of a well-adapted variety, and use of good quality seed all contribute to conditions allowing good competition with weeds. Soybean production requires good cultural practices. Prepare the seedbed prior to planting to kill germinating weeds. A rotary hoe or harrow may be used to control weeds after planting but before the soybean emerge or after emergence when soybean are in the 1 to 2 trifoliate leaf stage. Rotary hoe or harrow help activate PRE herbicides under dry conditions and increase weed control. The rotary hoe is an effective and economical weed control method when the ground is not trashy, lumpy or wet and when weeds are beginning to emerge. Cultivation is most effective when the soybean are slightly wilted during the warm part of the day, because the crop is less susceptible to breakage and the weeds will desiccate quickly. D2. Preplant 2,4-D at 0.75 to 1 pt/A of a 4 lb/gal concentrate may be applied 7 or more days prior to planting for the ester formulation or 14 or more days prior to planting for the amine formulation. 2,4-D amine or ester at 1 to 2 pt/A may be applied 30 or more days prior to planting. Plant soybean seed at least 1.5 inches deep. Planter press wheels should completely cover seed and separate seed from herbicide layer. 2,4-D may be tank-mixed with glyphosate, paraquat or other herbicides registered for preplant soybean application. Risk of soybean injury from preplant 2,4-D will depend on weather, rainfall, amount of weed vegetation, and previous crop residue. 2,4-D should not be applied if risk of injury and possible stand and yield loss cannot be accepted. Use only 2,4-D products that allow preplant application prior to planting soybean. Always read and follow 2,4-D label directions. D3. Assure II (quizalofop) at 7 to 10 fl oz/A, clethodim at 4 to 16 fl oz/A of 2 lb/gal formulation or 8.5 to 34 fl oz/A of 1 lb/gal formulation, Fusilade DX (fluazifop-P) at 5 to 12 fl oz/A, Fusion (fluazifop-P & fenoxaprop-P) at 4 to 12 fl oz/A, or Poast (sethoxydim) is a 0.5 to 1.5 pt/A plus petroleum oil adjuvant applied POST controls annual grasses and quackgrass. Apply with oil adjuvant at 1% v/v but do not use less than 1 pt/A. Oil adjuvant at more than 1 qt/A is not needed. MSO oils have performed equal to petroleum-based oil additives. See table in the soybean section for rates according to weed species and weed size. Quackgrass regrowth should be retreated when 4 to 8 inches tall. Poast only suppresses quackgrass. Most broadleaf herbicides tank mixed with POST grass herbicides will often reduce grass control compared to the grass herbicide applied alone. Reduced grass control can be avoided by applying the grass herbicide at least 1 day before or 5 days after application of a broadleaf herbicide. Assure II may provide excellent green foxtail control but less yellow foxtail control. Lower yellow foxtail control may result from applying Assure II at reduced rates, with broadleaf herbicides, or to large or stressed plants. Addition of fertilizer may enhance yellow foxtail control and control of stressed grasses. Clethodim is a ACCase mode of action herbicide, similar to Assure II, Fusilade, and Poast. However, in NDSU research clethodim controls many grasses documented resistant to other ACCase herbicides. It is recommended that clethodim be used in rotation with herbicides of different modes of action and in a resistant weed management program. Several generic brands of clethodim are available but not all formulations are identical to the original Select formulation. Select, Clethodim, Trigger and Volunteer are the same but Arrow, Prism, Section, and Select Max all have different formulations. Select Max is a 1 lb/gal formulation, contains activating adjuvants in the formulation, and allows use of NIS, PO, or MSO depending on tank-mix partner. D4. Basagran (bentazon) at 0.5 to 1 qt/A applied POST controls wild mustard, common cocklebur, Venice mallow, and sunflower and suppresses biennial wormwood and Canada thistle. NDSU research has shown greater broadleaf weed control, especially lambsquarters, redroot pigweed and kochia, by applying Basagran as split treatments either twice each at 1 pt/A, 3 times each at 0.67 pt/A, or 4 times each at 0.5 pt/A as compared to one application at 2 pt/A. Make applications 7 to 10 days apart depending on weed growth rate, growing conditions, size of weeds at application, degree of weed control from first application, and sequential flushes. The first application must be made to small weeds (<1 inch). The micro-rate may provide greater control of broadleaf weeds than from a single application at full rates and can be used in all crops where Basagran is labeled. Apply with oil additive at 1 qt/A (1 pt/A by air). Do not reduce the amount of oil adjuvant with the micro-rate. MSO adjuvant has shown greater enhancement of Basagran than petroleum oil (COC) adjuvants but the cost of MSO is higher. Basagran is safe to soybean at all stages. The total maximum seasonal use rate is 4 pt/A so the rate of the micro-rate can be increased if weeds are large at application or if sequential applications are delayed due to rain or wind. Rezult may be more economical than Basagran for grass and broadleaf weed control. If so, use the following chart.
For Canada thistle control, apply Basagran at 1 qt/A when plants are 8 inches tall to bud stage and make a second application at 1 qt/A 7 to 10 days later. Basagran is commonly combined with fertilizer micronutrients that may cause incompatibility problems resulting in zinc precipitation. Chelated zinc materials (black in color) have greater incompatibility problems than unchelated material (clear). Recommendations to prevent precipitation are to fill sprayer with water, add Basagran and thoroughly agitate, then add zinc fertilizer material. Rezult (bentazon & sethoxydim) at 3.2 pt/A (1.6 pt/A Rezult G and 1.6 pt/A Rezult B) applied POST controls some grass and broadleaf weeds. Apply with oil adjuvants at 1 to 2 pt/A. Refer to label or narrative for tank-mix options. Rezult is priced economically compared to other POST herbicide programs. Refer to Poast sections for additional information. D5. Cobra (lactofen) at 4 to 12.5 fl oz/A or Ultra Blazer (acifluorfen) at 0.5 to 1.5 pt/A applied POST controls some broadleaf weeds, including lanceleaf sage. Apply with Cobra with oil additive at 0.5 to 1 pt/A or Ultra Blazer with NIS at 0.125% v/v . Cobra is a contact herbicide and requires thorough spray coverage for good weed control. Soybean beyond the third trifoliate leaf stage may interfere with spray interception and reduce weed control. Herbicides will burn soybean leaves but will usually recover. Apply between daytime temperatures of 70 to 85 F. See Cobra label to suppress white mold. D6. FirstRate (cloransulam) at 0.6 to 0.75 oz WDG/A applied PPI or PRE controls common cocklebur, common lambsquarters, horseweed (marestail), pigweed species, annual smartweeds, common and giant ragweed, sunflower, and velvetleaf or at 0.3 oz 80WDG/A applied POST to soybean prior to flowering controls cocklebur, Venice mallow, horseweed (marestail), common ragweed, annual smartweed, sunflower, and velvetleaf and suppresses giant ragweed. Apply to broadleaf weeds less than 10 inches tall. FirstRate gives no nightshade control. Apply with NIS at 0.125 to 0.25% v/v + 28% UAN at 2.5% v/v. Oil additive can be used with or without fertilizer. See label for tank-mix options. See FirstRate under the herbicide residue section for crop rotation restrictions. D7. Flexstar (fomesafen + adjuvants) applied POST at 0.75 to 1 pt/A controls common cocklebur, annual smartweed, wild mustard, nightshade, pigweed, waterhemp, common and giant ragweed, Venice mallow and small kochia (including ALS resistant). Apply to broadleaf weeds 2 to 4 inches tall. Apply 1 pt/A in ND east of I-29 and south of I-94 and in MN south of I-94. Apply at 0.75 pt/A in ND east of Hwy 281 and in MN south of U.S. Hwy 2. Apply with NIS at 0.25 to 0.5% v/v or oil adjuvant at 0.5 to 1% v/v. Oil adjuvant increase weed control but also increase risk of soybean injury. NDSU research has shown good to excellent kochia control when Flexstar is applied at high spray volumes (>17 gpa), with oil adjuvants (especially MSO type), at labeled rates, and to kochia less than 3 inches tall. Soybean injury may result when Flexstar is tank-mixed with EC formulation herbicides which act as additional oil adjuvant. Activity of fomesafen increases and risk of crop injury increases as temperature and humidity increases. A maximum of 0.75 pt/A is allowed in most of ND while 1 pt/A is allowed through the Midwest. The reduced fomesafen rate reduces carryover and crop rotation restrictions. Flexstar is labeled on soybean and Reflex is labeled on dry bean. Flexstar contains adjuvants lacking in the Reflex formulation. Reflex may give less consistent weed control than Flexstar and will require better management strategies to achieve adequate weed control. See label or crop rotation restriction section for additional information. D8. Intrro at 2 to 3 qt/A applied PPI or PRE, metolachlor or s-metolachlor at 1 to 2 pt/A applied PPI or PRE, Outlook at 12 to 21 fl oz/A applied PPI, PRE, or EPOST up to third trifolioliate stage control annual grass and some broadleaf weeds, including redroot pigweed and common lambsquarters but are ineffective against wild oat. Apply the higher rate on clay soils high in organic matter. Soybean has good tolerance and incorporation improves consistency of weed control. Dual products may be surface applied or incorporated in the fall after October 15 but before ground freezes or applied in the spring. D9. Pursuit (imazethapyr) at 3 fl oz/A applied POST controls or suppress many broadleaf weeds, except ALS resistant. Pursuit has controlled foxtail, marshelder, Russian thistle, common cocklebur, sunflower, smartweed, and lanceleaf sage in NDSU field trials. Pursuit will not control Venice mallow, horseweed, wild buckwheat, common lambsquarters and common ragweed. POST application may not provide adequate soil residual to control subsequent flushes of nightshade due to plant foliage intercepting most of the spray. However, even a small amount of Pursuit may give a reduction in number and intensity of flushes of other weeds. Pursuit is enhanced greatest by MSO (1.5 pt/A) and basic pH blend (1% v/v) adjuvants. UAN fertilizer improves weed control, especially common lambsquarters. Crop injury may result if either Pursuit or thifensulfuron is applied sequentially or tank-mixed together. In sequential application, the first herbicide reduces the ability of soybean to metabolize the second herbicide. Weeds not controlled by the first herbicide may not be controlled after the second herbicide is applied. This is particularly important for lambsquarters. Weeds that escape control from the first herbicide may be larger than labeled size by the time soybean can safely be treated with the second herbicide. Delay cultivation for 14 days after application to avoid reduction in weed control. Tank-mixtures of Pursuit with Assure II, Fusilade DX, Fusion, or Select may result in reduced grass control. Reduced grass control can be avoided by applying the POST grass herbicide either 1 or more days prior to or at least 5 days after Pursuit. Pursuit Plus (imazethapyr & pendimethalin) at 1.8 pt/A applied PPI controls most annual grass and broadleaf weeds, including wild buckwheat. ND state labeling allows use in ND only south of State Highway 2 at a reduced rate of 1.8 pt/A which is 75% of the full labeled rate. Pursuit Plus at 1.8 pt/A contains the equivalent of Pursuit at 3 fl oz/A plus 1.75 pt/A of Prowl EC. Add additional Prowl EC at 1.75 pt/A for more consistent weed control. Thoroughly incorporate into the top 1 to 2 inches of soil. Refer to paragraphs on Pursuit and Prowl for additional information on use and restrictions. D10. Python (flumetsulam) at 0.8 to 1.33 oz 80WDG/A applied PPI or PRE will control many annual small-seeded broadleaf weeds in soybean, such as nightshade, pigweed, kochia, biennial wormwood, common lambsquarters, mustard, annual smartweed, Venice mallow, and Russian thistle. Python does not control large-seeded broadleaf weeds like common and giant ragweed and common cocklebur. Python requires soil moisture for optimum weed control. Python is also strongly affected by soil pH. High soil pH increases herbicide activity and increases speed of herbicide degradation, but also increases risk of crop injury. Excellent broad spectrum weed control may occur when applied on soils with above 7.5 pH, when significant precipitation occurs after application, when rates are based on soil texture and organic matter content, and under light to moderate weed infestations. Some stunting may occur under poor growing conditions on soils with pH greater than 8.0. Use the higher rates on medium to fine textured soils and the lower rates on coarse textured soils. PPI treatments may be applied up to 30 days before planting and incorporate uniformly into the top 2 inches of soil. Do not apply to soils with a pH greater than 8.0 as crop injury may result. Apply Python with most soil-applied herbicides labeled in soybean. See Python under the Herbicide Residue section for information on crop rotation restrictions. D11. Raptor (imazamox) at 4 fl oz/A POST plus a soil-applied grass herbicide or Raptor alone at 5 fl oz/A alone POST controls nearly all annual grass and broadleaf weeds in soybean except wild buckwheat, large common lambsquarters, common and giant ragweed, Venice mallow, horseweed, biennial wormwood, and ALS-resistant weeds. In NDSU field trails, Raptor has controlled marshelder, Russian thistle, and lanceleaf sage less than 1 inch tall. Soil residue of Raptor will not control late germinating weeds or weed flushes later in the growing season after rain events. Raptor as compared to Pursuit has greater grass and broadleaf weed control, provides improved common lambsquarters control, and has less carryover and crop rotation restrictions. Apply Raptor with basic pH blend adjuvant at 1% v/v or MSO type adjuvants at 1.5 pt/A. Alternatively, apply with NIS at 0.125 to 0.25% v/v or oil concentrate at 0.5% v/v plus 28% UAN liquid fertilizer at 4% v/v. Use of 28% UAN improves control of some weeds like common lambsquarters. MSO type oil additives should be used when weeds are large and/or stressed. MSO or basic pH blend adjuvants enhance weed control more than NIS or some petroleum oil additives with or without 28% UAN. However, Raptor applied with MSO + UAN may result in crop injury at temperatures greater than 88 F and greater than 80% relative humidity. Refer to label and paragraph on Pursuit and Raptor for information and restrictions when applying Raptor before or after thifensulfuron or tank-mixing with thifensulfuron or other POST grass herbicides. Crop rotation restrictions are less with Raptor than Pursuit. However, like Pursuit, Raptor carryover is affected by soil pH. As soil pH increases, rate of Raptor degradation increases. At soil pH less than 6.5, rate of breakdown is slow and injury to sugarbeet and other sensitive crops may occur if planted before allowed time interval. See label or Raptor under the herbicide residue section for information on crop rotation restrictions. D12. Sencor (metribuzin) at 0.25 to 0.5 lb 75DF/A controls annual broadleaf weeds, including wild mustard. Adjust rate according to soil type, pH, and % organic matter. Some soybean varieties are susceptible to metribuzin; consult label for list of susceptible varieties. Soybean injury can be reduced by using herbicide combinations with lower rates of metribuzin. D13. Sonalan (ethalfluralin) at 1.3 to 3.5 pt/A, trifluralin at 1 to 2 pt 4E/A, or Prowl/H20 (pendimethalin) at 2 to 3 pt/A EC applied PPI controls most annual grasses and some small-seeded broadleaf weeds. They give no wild mustard, common cocklebur and sunflower control. Requirements for proper timing and depth of incorporation differ for each herbicide. Adjust rate according to soil type. Trifluralin must be incorporated in the top 2 to 3 inches of soil within 24 hours of application. Trifluralin incorporation may be delayed up to 2 days if applied to a cool, dry soil. Incorporation of Sonalan 10G can delayed 3 to 5 days after application. Herbicides can be applied with most soil PPI herbicides labeled in soybean. Sonalan has less soil residue than trifluralin or Prowl and is more active at comparable rates. D14. Spartan (sulfentrazone) at 3 to 8 fl oz/A applied shallow PPI or PRE controls most annual small-seeded broadleaf weeds including ALS resistant kochia, pigweed species, common lambsquarters, eastern black nightshade, annual smartweed, Russian thistle and biennial wormwood. Spartan may partially control other weeds like wild buckwheat, marshelder, wild mustard, common ragweed, hairy nightshade, Venice mallow, and foxtail but provides no perennial weed control. Rate must be adjusted for soil texture, soil pH and organic matter content. Apply 3 to 6 fl oz/A for coarse and medium textured soils, and 4 to 8 fl oz/A for fine textured soils. Herbicide solubility, activity, and phytotoxicity increases as soil pH increases. User must read and follow label for rate information to ensure adequate weed control. Spartan provides excellent burndown weed control and may be applied up to 30 days prior to planting but use the higher rate in the appropriate rate range. Spartan can be tank-mixed with most PPI/PRE herbicides registered in soybean. NDSU research has shown that consistent control of susceptible broadleaf weeds and suppression of foxtail and marginally susceptible broadleaf weeds depends on at least 0.5 to 0.75 inch rainfall shortly after application and before weeds emerge. Spartan will leave a residue in soil for more than one year. Refer to label or crop rotation restriction section for additional information. D15. Thifensulfuron at 1/8 oz SG/A or 1/12 oz DF/A applied POST controls wild mustard, common lambsquarters, and pigweed and suppresses other broadleaf weeds. Apply with NIS at 0.125 to 0.25% v/v or oil adjuvants at 0.5% v/v plus liquid fertilizer at 4% v/v. DO NOT apply with oil adjuvants when tank-mixing with any other herbicide or severe crop injury may occur. See label or Pursuit paragraph for precautions when tank-mixing with Pursuit and other herbicides. Thifensulfuron as spray drift or sprayer contamination may cause severe injury to susceptible crops such as sugarbeet and sunflower. Thoroughly clean sprayer to prevent contamination of subsequent spray mixture and injury to susceptible crops. Follow label for improved cleanout procedure. D16. Valor (flumioxazin) at 2 to 3 oz WDG/A applied EPP or PRE controls most small-seeded broadleaf weeds including kochia (including ALS resistant), nightshade, pigweed species, lambsquarters, and Venice mallow and may suppress common and giant ragweed, annual smartweed, Russian thistle, and foxtail and may suppress wild buckwheat. Valor does not control perennial weeds. Apply Valor from 14 days prior to seeding to just before soybean emergence. Valor can be applied with glyphosate in early burndown programs in soybean. Valor requires a minimum of 0.25 inch of rain for activation and requires a bioassay prior to planting sensitive crops. See label for additional information. Gangster (flumioxazin & cloransulam), a copack of Valor and FirstRate at 1.5 to 3 + 0.3 to 0.6 oz WDG/A, applied EPP or PRE controls most small-seeded broadleaf weeds including ALS-resistant kochia, nightshade, pigweed species, lambsquarters, ragweed, sunflower, smartweed, Venice mallow, and suppress foxtail. Gangster does not control perennial weeds. Apply from 14 days prior to seeding to just before soybean emergence. Gangster can be applied with glyphosate in EPP burndown programs. Refer to label for weeds controlled, rates, and crop rotation restrictions. ROUNDUP READY SOYBEAN D17. Gyphosate at 0.38 to 1.125 lb ae/A applied only to Roundup Ready soybean will control most annual and perennial weeds. Refer to label for adjuvant use. Apply with AMS. Application timing may not be appropriate for effective perennial weed control. Glyphosate is a non-selective, non-residual, translocated herbicide that can control grasses at rates as low as 1.5 oz ae/A. Labeled rates are required to control broadleaf weeds. However, some broadleaf weeds like kochia, nightshade, wild buckwheat, horseweed (marestail), dandelion, and lambsquarters may not be adequately controlled by one application of glyphosate. Refer to label for weeds controlled, application information, timing, tank-mix options, and other restrictions. Glyphosate will control weeds resistant to other herbicides. ROUNDUP/STS READY SOYBEAN D18. Thifensulfuron at up to 0.5 oz SG/A or 0.33 oz DF/A applied with glyphosate only to Roundup Ready/STS (sulfonylurea tolerant) soybean improves broadleaf weed control. Thifensulfuron is effective on wild buckwheat, mustard species, common lambsquarters, pigweed species, annual smartweed, and will suppresses other broadleaf weeds. Apply with NIS at 0.125 to 0.25% v/v to non-loaded glyphosate formulations. Refer to glyphosate label for application and adjuvant information.
DRY BEAN E1. Navy bean generally is less tolerance to herbicides than
other dry beans types or soybean. Rotary hoe before crook
stage or after emergence up to 1 to 2 trifoliates. E2. Eptam (EPTC) at 2.3 to 3.5 pt/A or 11 to 15 lb 20G/A plus
Prowl, Sonalan, or trifluralin controls many grass and broadleaf
weeds including wild oat and common lambsquarters. Incorporate 4 to 6 inches deep immediately after application. Do not use
Eptam on soybean. E3. Intrro (alachlor) at 2 to 3 qt/A only PPI, metolachlor or S-metolachlor at 1 to 2 pt/A PPI or PRE, or Outlook
(dimethenamid) at 1 to 2 pt/A PPI, PRE or EPOST up to the
third trifoliate controls annual grasses and some broadleaf
weeds. PPI may provide more consistent weed control because
PRE and EPOST treatments require rainfall for activation.
Outlook can be applied in sequential treatments for improved
nightshade control in dry bean. Outlook PPI or PRE provides
greater nightshade control than Dual or Lasso but may degrade
in soil before nightshade emergence ceases. Apply Outlook
EPOST up to third trifoliate dry beans to reduce late nightshade
emergence. E4. Pursuit (imazethapyr) at 2 fl oz/A applied PPI, PRE or POST
controls many broadleaf weeds including wild mustard and nightshade in most dry bean types and field pea. Pursuit can be
applied ONLY PPI within 1 week of planting or PRE up to 3 days
following planting to chickpea/garbanzo bean and lentil at rates
listed above. DO NOT apply POST to chickpea/ garbanzo bean or lentil, or
Domino variety black turtle bean. Do not apply after crop has
begun flowering, if planting is delayed, or cold and/or wet
weather are present or predicted to occur within one week of
application. Do not use oil additives or liquid fertilizer. Apply with
NIS at 0.25% v/v to dry beans with at least one trifoliate leaf.
Refer to the Raptor paragraph in the soybean section for
additional information on application use and restrictions. Refer
to label for crop rotation restrictions and application information. User assume all risk of liability for injury. E5. Reflex (fomesafen) at 0.75 pt/A applied POST with NIS at
0.25 to 0.5% v/v or oil adjuvant at 0.5 to 1% v/v controls many
broadleaf weeds. Oil adjuvant may increase weed control but
also increases risk of dry bean injury. Refer to the Flexstar
paragraph in the soybean section for information on application
and adjuvant use and restrictions. E6. NDSU Dry Bean Micro-rate concept is based on the
Sugarbeet Micro-Rate and substitutes additional weed
management for reduced herbicide rates. Application to small
weeds is essential for success. The micro-rate can be applied
more than once in dry beans to control emerging weed flushes
but applying a foundation herbicide treatment (DNA or
acetanilide) may require only one application. MSO adjuvant is
required for optimum weed control. The POST grass herbicide
can be excluded if grass populations are low. Preliminary data
show weed control can be improved by increasing spray volume.
The first application can be made at 10 gpa when weeds are
small and less than 3 inches tall. Increase spray volume by 10
gpa for every 3 inches in weed height. Addition of AMS at 1 lb/A
also increases weed control. Weed control from the micro-rate is
best when temperature plus humidity is greater than 140.
Increasing spray volume and using AMS may help improve weed
control when the value is below 140. FIELD PEA F1. Field pea is a poor competitor with weeds in the early seedling
stage. Small weeds can be controlled by harrowing before crop emergence and when pea is 3 to 7 inches tall. Apply broadleaf herbicides
to small weeds and small pea to reduce risk of pea injury. Do not
apply POST herbicides when temperatures are above 85 F or when
pea are under heat/drought stress. F2. Basagran (bentazon) at 1 to 1.5 pt/A applied to 2- to 4-inch tall
field pea controls some annual broadleaf weeds and suppresses
Canada thistle. Apply in 15 to 20 gpa with MSO type oil additive. Two
sequential applications 7 to 10 days apart each at 1 pt/A provides
greater broadleaf weed control than one application at the full rate. A
second application can be made to pea greater than 6 inches tall.
Allow a 30 day PHI. See paragraph under Basagran in soybean
section for additional information. F3. Thistrol (MCPB) at 2 to 6 pint/A applied to 4- to6-inch pea vines
controls some broadleaf weeds including lambsquarters and redroot
pigweed and suppression of Canada thistle. Slight pea injury may
occur but pea will usually recover. Injury potential increases when
pea is taller than 6 inches and when temperatures exceed 85 F or
when the pea is under heat/drought stress. Apply prior to flowering. F4. Glyphosate at up to 0.75 lb ae/A applied preharvest at the hard
dough stage of pea grain with 30% or less moisture controls most
annual and perennial weeds. Allow a 7 day PHI. Greater perennial
weed control may be obtained by allowing a 10 to 14 day PHI. Do not
apply to crop grown for seed. Glyphosate at 1.5 to 2.25 lb ae/A or in a 2% solution for hand-held
sprayers applied as a spot treatment at or beyond the bud stage of
perennial weeds controls many troublesome weeds including Canada
thistle, perennial sowthistle, common milkweed, or quackgrass. The
crop in treated areas will be killed. Allow a 14 day PHI. No more than
10% of the total field area may be spot treated at rates greater than 1
qt/A. F5. Metri and Metribuzin (metribuzin) at 0.25 to 0.33 lb DF/A will
suppress mustard species and lambsquarters. Crop injury may result
if pea is under stress caused by cold weather. Apply when weeds are
less than 2 inches in height or diameter and before the crop is 6
inches tall. Apply Sencor no later than 50 days before harvest. CHICKPEA/GARBANZO BEAN G1.
Chickpea/Garbanzo beans is a poor competitor with weeds
in the early seedling stage. Small weeds can be controlled by
harrowing after seeding up to 3 to 5 days after chickpea
germination and again when chickpea is 2 to 4 inches tall. Apply
broadleaf herbicides to small weeds and small chickpea to
reduce risk of pea injury. Do not apply POST herbicides above
85 F or when chickpea is under heat/ drought stress. H1. Lentil is a poor competitor with weeds in the early seedling
stage. Small weeds can be controlled by harrowing before crop
emergence and when lentil is 3 to 7 inches tall. H2. Metri and Metribuzin (metribuzin) applied PRE at 0.33 to
0.5 lb 75DF/A or POST at 0.167 to 0.25 lb 75DF/A in lentil will
suppress common lambsquarters, mustard species, henbit, and
common chickweed. Apply Sencor PRE before or after planting
but before crop emerges. Thorough incorporation by rainfall or
mechanical methods is essential for weed suppression. Apply
Sencor POST to weeds less than 2 inches tall and lentil less
than 6 inches tall. See label for special precautions. H3. Trifluralin at 1 to 1.5 pt/A or 5 to 7.5 lb 10G/A applied fall or
spring controls grass and some broadleaf weeds. Rates should
be adjusted based on soil texture and organic matter. Lentil
tolerance to trifluralin is marginal, so injury can occur. Cool soil
conditions over an extended period of time will delay germination
and emergence and increase risk of injury. Trifluralin spring-applied is more likely to cause stand reduction than when fall-applied. If seeding into cool, dry soil after a spring application,
the seeding rate should be increased by 15% to compensate for
injury that may occur. Seed no deeper than 1.5 inches to reduce
the potential for lentil injury. SUNFLOWER J1. Sunflower competes poorly with weeds because of slow
early growth and minimal ground cover. Cultivation with a spike-
tooth or coil spring harrow about 1 week after seeding but before
sunflower emergence will kill weeds that emerge before
sunflower. Harrow or rotary hoe when sunflower has at least 4
leaves. Cultivation will control weeds between the rows. J2. Assert (imazamethabenz) at 0.6 to 0.8 pt/A applied POST
controls wild mustard in sunflower up to 15 inches tall. Severe
sunflower injury may occur when applied in high temperature
and humidity. Sunflower variety, growth stage, weather
conditions, humidity, spray volume, and additives may affect
sunflower safety. Risk of injury should be considered when
deciding if treatment is warranted. Do not apply to sunflower
under drought or heat stress. Apply Assert when air temperature
plus relative humidity is below 150. Sunflower damage may
range from plant stunting to head deformation. Refer to label. J3. Spartan (sulfentrazone) at 3 to 6 fl oz/A applied EPP, shallow
PPI, or PRE controls most annual small-seeded broadleaf weeds,
such as ALS-resistant kochia, pigweed species, common
lambsquarters, eastern black nightshade, annual smartweed,
Russian thistle, and biennial wormwood. Sulfentrazone may partially
control wild buckwheat, marshelder, wild mustard, common ragweed,
hairy nightshade, and foxtail but provides no perennial weed control.
Rate must be adjusted for soil texture, soil pH, and organic matter
content. Herbicide solubility, activity, and phytotoxicity increases as
soil pH increases. User must read and follow label for rate
information to ensure adequate weed control while maintaining crop
safety. Crop injury will be minimized and greater likelihood of
activation by rainfall will result if applied up to 30 days prior to
planting. Sunflower has good tolerance to Spartan on medium to fine
textured soils with OM above 3%. Crop injury may occur on soils with
low OM and soil pH greater than 7.5, especially on calcareous
outcropping. Do not use on coarse textured soils with less than 1%
organic matter. Close furrow at planting to reduce injury. Poor
growing conditions at and following crop emergence, cold
temperatures, soil compaction, or rate too high based on soil type
and OM may result in crop injury. NDSU research has shown that
consistent control of susceptible broadleaf weeds and suppression of
foxtail and marginally susceptible broadleaf weeds depends on at
least 0.5 to 0.75 inch rainfall shortly after application and before
weeds emerge. The approximate ranking of crops from most to least
tolerant is soybean, flax, chickpea, mint, sunflower, potato, field pea,
dry edible beans, safflower, crambe, canola, lentil, and sugarbeet.
Spartan has a PPO inhibitor mode of action and will leave a residue
in soil for more than one year. Refer to label section for additional
information. HERBICIDE RESISTANT SUNFLOWER Clearfield Sunflower J4. Beyond (imazamox) at 4 fl oz/A applied POST to Clearfield
sunflower hybrids controls most annual grass and broadleaf weeds
with limited crop rotation restrictions. Apply with NIS and UAN. MSO
adjuvants are not restricted and will provide greater herbicide
enhancement compared to NIS + UAN. However, MSO adjuvants
may increase risk of temporary sunflower yellowing and stunting.
Weed species that may not be controlled are wild buckwheat,
ragweed, common lambsquarters (> 2 inches), biennial wormwood,
Canada thistle, and ALS resistant kochia. Refer to the Raptor
paragraph in the soybean section for information on application and
use restrictions. Express Sun Sunflower J5. Tribenuron at 0.25 to 0.5 oz SG/A or 0.33 to 0.67 oz DF/A
applied POST to Express Sun sunflower hybrids controls most
broadleaf weeds and Canada thistle. Tribenuron does not control
grasses or ALS resistant weeds. MSO adjuvants will enhance weed
control more than other adjuvant types. Tribenuron may antagonize
POST grass herbicides is applied together. The antagonism can be
reduced or avoided by applying a higher rate of the grass herbicide or
applying the grass herbicide 1 or more days before or 5 to 7 days
after tribenuron application. Do not apply any other ALS herbicide on
Express Sun sunflower varieties, even other SU herbicides or severe
sunflower injury or death will result. Refer to label for use directions
and other information.
K1. Flax is less competitive with weeds than small grains and
should be grown on relatively weed-free fields. Control weeds in
and following harvest of preceding crop. Post-harvest tillage of
small grain stubble will prevent weed seed production, suppress
perennial weeds, and encourage annual weed seed germination
prior to freeze-up. Flax should be seeded directly or with shallow
spring tillage in fields. Deep tillage of fields could bring dormant
seeds to the surface and increase weed problems. For weedy
fields, moldboard plow the soil to bury weed seeds, thereby
reducing the weed infestation the following crop season.
Moldboard plowing can reduce infestations of small-seeded
weeds like foxtails and kochia, which have short seed survival.
Delayed seeding of flax with tillage prior to seeding will control
wild oat and reduce infestations of other early germinating
weeds. However, delayed seeding generally reduces flax yields.
Early maturing flax varieties should be used with late seeding.
Weed control is needed by flax emergence to reduce yield
losses since flax is a poor competitor with weeds. Soil-applied herbicides reduce weed emergence and minimize early weed
competition to maximize flax yields. POST herbicides applied
soon after weed emergence to small weeds and flax usually give
better control and allow more time for flax recovery from possible
herbicide injury than treatment to larger weeds and flax. K2. Bromoxynil at 1 pt/A on 2- to 8-inch flax controls some
broadleaf weeds. Some flax leaf burn may occur when applied
during high temperatures. Bromoxynil plus MCPA may cause flax
injury when applied during hot, humid conditions. K3. Clopyralid & MCPA at 1.33 to 1.75 pt/A control Canada
thistle and many other broadleaf weeds and at 1.75 pt/A
suppresses perennial sowthistle. Apply when flax is 2 to 6 inches
tall. Adverse growing conditions prior to, during, and following
application may reduce weed control and increase risk of flax
injury. K4. MCPA at 0.5 pt/A on 2- to 6-inch flax controls broadleaf
weeds. MCPA ester or high MCPA amine rates should be used
in flax for improved kochia and Russian thistle control. K5. Trifluralin at 1 to 2 pt/A or 5 to 10 lb 10G/A fall-applied on
fields to be seeded to flax. Granular formulations may be applied
to standing stubble. Use liquid or granular formulations when
residue will not interfere with incorporation. Seed flax less than
1.5 inches deep into a moist seedbed. Incorporate shallow and
seed deep or seed shallow with deep incorporation to maximize
crop safety. Trifluralin is not labeled for spring application in flax because of
injury risk but may be spring-applied if user assumes all liability
for crop safety. To reduce potential of flax injury, spring-apply no
more than 0.5 lb ai/A and incorporate as early as possible to
create a firm seed bed through rain and soil compaction. A firm
seed bed will promote uniform depth-seeding for uniform
emergence. Early application will allow more time for
degradation of "hot spots" in soil. CANOLA AND MUSTARD CROPS L1. Mustard crops in the early seedling stage are poor competitors
with weeds. Control small weeds by harrowing until 3 to 5 days after
mustard germination. Harrowing after emergence is not
recommended. L2. Clopyralid at 0.33 to 0.5 pt/A applied POST controls several
broadleaf weeds and volunteer crops in canola, rapeseed, and
crambe. Clopyralid at 0.25 to 0.5 pt/A is most effective when applied
to common cocklebur, giant ragweed, volunteer sunflower, wild
sunflower, volunteer alfalfa, and volunteer soybean up to the 6-leaf
stage, common ragweed up to the 5-leaf stage; and wild buckwheat
in the 3- to 5-leaf stage before vining begins. Clopyralid at 0.5 to 0.66
pt/A is most effective on Canada thistle in the rosette to pre-bud
growth stage but rosette application often gives better control than
later application. HERBICIDE RESISTANT CANOLA CLEARFIELD CANOLA L3. Beyond (imazamox) at 4 fl oz/A applied POST to Clearfield
canola varieties from emergence until prior to flowering controls most
annual grass and broadleaf weeds. Apply with NIS at 0.25% v/v alone
or with UAN liquid fertilizer at 1 to 2 qt/A. Beyond will not control ALS-resistant weeds. Clearfield canola can be planted on land previously
treated with Assert or Pursuit and may reduce or eliminate injury from
long residual SU herbicides. See label or information on Raptor in the
soybean section for use, weed control, carryover, crop rotation
restrictions, and other use information. LIBERTY LINK CANOLA L4. Liberty (glufosinate) at 34 fl oz/A applied POST to Liberty
tolerant canola from cotyledon to bolting stage controls most annual
broadleaf weeds, controls or suppresses grasses, and may suppress
perennial weeds. Always apply with AMS at 3 lb/A. If tank mixing with
Assure II, clethodim, or Poast then reduce AMS to 1.5 lb/A. Liberty is
a non-selective, non-residual, contact type herbicide with limited
translocation and should be applied to small weeds. Refer to label for
weeds controlled, application information and timing, tank-mix
options, and other restrictions. Liberty has a unique mode of action
and may be used in weed resistance management. ROUNDUP READY CANOLA L5. Glyphosate applied at a maximum of 0.38 lb ae/A with no more
than two applications to glyphosate-resistant canola from emergence
to bolting controls most annual and perennial weeds. Apply with
AMS. Application timing may not be appropriate for effective
perennial weed control. Glyphosate is a non-selective, non-residual,
translocated herbicide. Full labeled rates are required for broadleaf
weed control. Glyphosate will control weeds resistant to other
herbicides. Refer to label or paragraphs on glyphosate under
herbicide-resistant corn or soybean sections for weeds controlled,
application information and timing, tank-mix options, and other
restrictions. Continue to next page
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