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2008 North Dakota Weed Control GuideW-253, January 2008 SMALL GRAINS - SPRING, DURUM AND WINTER WHEAT, BARLEY, AND OAT. IDENTIFYING LEAF STAGES OF SMALL GRAIN: The plant leaf stage is determined by the number of leaves present on the main stem. Leaves arise on opposite sides of the stem and develop a collar at the junction of the leaf sheath and leaf blade. The first leaf has a blunt tip. Position the small grain plant with the first leaf pointing to the left. All leaves on the left side of the main stem are designated with an odd number and those on the right side with an even number. Count the youngest leaf when it is at least one-half the length of the leaf below it. Follow this procedure to properly stage small grain plants. Tillers (stooling) usually start to appear at the third to fifth leaf stage. Most tillers arise between the main axis (stem) and leaf. A coleoptilar tiller may also be present. The coleoptilar tiller originates below the soil (near the seed) and is located on the opposite side of the stem from the first leaf. Frequently, tiller leaves are confused with leaves of the main stem when determining correct leaf stage. Remember to count the leaves on the main stem, but do not include tiller leaves in the leaf stage count. Leaf stage determination in the field can be complicated by loss of older leaves; for example, the first and second leaves may have been removed by abrasion from wind blown soil, drought, frost, disease, or some other form of weathering. The base of the stem should be carefully examined for evidence of scars from lower leaves that have been removed. Such leaves must be counted when making correct leaf stage determination. Plant growth rate varies considerably, and the approximate days after emergence for appearance of a given leaf stage is influenced mostly by temperature. Daytime highs less than 55 F delay development, while warm temperatures advance development. Days to emerge can vary greatly depending on soil temperature and moisture. HARROWING FOR WEED CONTROL: Harrowing a few days after a spring sown crop has sprouted but before emergence is effective in reducing stands of foxtails, wild oat and other weeds. The weeds must be emerging. Since foxtails are shallow rooted, set the teeth back on the harrow to minimize crop injury. Also, small grains can be harrowed after they have 2 or 3 leaves but before tillering. Harrowing should be performed when a dry soil surface exists so damaged weeds will desiccate rather than be transplanted. Wheat can be harrowed one to three times but barley only once. Oat normally is not harrowed because risk of injury is greater than to wheat or barley. HERBICIDE USE IN SMALL GRAINS: B1. Weed control in small grains is required to achieve a profitable yield. Applicable cultural control techniques plus use of herbicides or mixtures may be required to control all weeds. Normal height wheat varieties, rye, and winter wheat are more competitive than semi-dwarf wheat. Herbicides generally are most effective when the crop is competitive. Small grains underseeded to sweetclover, alfalfa, or other legumes should not be treated with ALS or growth regulator herbicides because serious injury or death of the legumes may result. However, bromoxynil is registered for use on small grain/legume mixtures even though some legume injury may occur. B2. Small grains are susceptible to 2,4-D during the seedling stage but can be treated safely with MCPA from emergence until prior to the boot stage. Do not treat small grains in the boot stage. Wheat and barley, when treated from 5-leaf until prior to the boot stage, are more tolerant than oat to 2,4-D. Wheat and barley varieties differ little in tolerance to MCPA and 2,4-D. Oat is more tolerant to MCPA than to 2,4-D, but injury to oat is possible with either chemical at any growth stage. Use 2,4-D on oat only for such hard-to-kill weeds as Russian thistle, common ragweed, and redroot pigweed and only when the crop is in the 3- to 4-leaf stage. While some injury to oat can be expected, the better control of these weeds with 2,4-D usually will compensate for any yield loss caused by oat injury. Several brands of 2,4-D are available, but there are some differences in application information; for example, Hi-Dep allows use at spray volumes as low as 1 gpa by ground or 0.5 gpa by air. B3. Achieve (tralkoxydim) is labeled for use only in certain geographic areas. Do not apply Achieve on spring wheat in South Dakota, Minnesota, or east of ND Hwy 281. Also, do not apply Achieve in the following counties in North Dakota: Dickey, La Moure, Stutsman, Foster, Eddy, Ramsey, and Towner. Achieve applied in these restricted areas may injury spring wheat. Syngenta will not be liable for injury to spring wheat if Achieve is used in restricted areas. Achieve at 6.9 fl oz/A applied POST controls green and yellow foxtail, wild and volunteer tame oat, Persian darnel, and annual ryegrass in wheat, durum and barley from 2-leaf to boot stage. Apply Achieve to actively growing 1- to 5-leaf foxtails, 1- to 4-leaf Persian darnel, and 1- to 6-leaf wild oat. Forage grasses have good tolerance to Achieve. Grass weed control may be poor and retillering may occur if plants are stressed at application. Apply Achieve at 10 to 15 gpa by ground or 3 to 5 gpa by air. Use of water volumes higher than listed may result in reduced grass weed control. Achieve Liquid is formulated with Supercharge adjuvant. One box of Achieve (herbicide + adjuvant) will treat 40 acres at 7 oz DG/A. Always add AMS at 7 to 15 lb/100 gallon water to reduce antagonism from water sources with high bicarbonate levels (> 400 ppm bicarbonate ions), or broadleaf herbicide tank-mixture, or to increase control of stressed weeds. Achieve can be tank-mixed with MCPA ester + or - bromoxynil (maximum of 1 pt/A), 2,4-D ester, clopyralid + MCPA (maximum of 2 pt/A), thifensulfuron, and Starane. Tank-mixing other herbicides, especially dicamba or ALS herbicides, will result in reduced grass weed control. If other herbicides are used, apply Achieve five or more days before the broadleaf herbicide. B4. Aim (carfentrazone) at 0.5 fl oz 2EW/A applied POST controls small (1 to 2 inch) nightshade, pigweed, lambsquarters, small kochia (including ALS resistant types), wild buckwheat, and top-growth control of field bindweed in wheat, barley, and oat. Add NIS at 0.25% v/v. Aim may be tank-mixed with most herbicides registered in wheat. Aim is a contact herbicide, requires application to small weeds, and may produce speckling and spotting on crop leaves receiving spray. Symptoms should disappear soon after new growth appears. Degree of speckling is affected primarily by sunlight intensity, humidity, and moisture. Higher humidity and moisture at application increase risk of leaf burn but usually the crop quickly recovers. Data shows that Aim may be safened when tank-mixed with SU herbicides. B5. Amber (triasulfuron) at 0.28 to 0.35 oz 75DF/A or Rave (triasulfuron & dicamba-Na) at 2 oz WDG/A applied POST in barley and 4 oz WDG/A in wheat applied POST controls several broadleaf weeds plus partial control of Canada thistle in wheat and barley. Burndown (speed of weed death) is slower for Amber than other SU herbicides. Amber is similar to Glean in weed control and carryover. Refer to Glean section. Amber and Rave may persist in soil for 4 years or more. Consult label or herbicide carryover/residue section for rotational crop restrictions. B6. Assert (imazamethabenz) at 1 to 1.5 pt/A applied POST controls wild mustard and wild oat in wheat and barley. Apply Assert to 1- to 4-leaf wild oat and to wheat and barley in the 2-leaf to jointing stage. Assert also suppresses wild buckwheat that has 3 leaves or fewer. Assert should be applied to small wild oat plants for optimum control. Apply with MSO type oil for greater and more consistent weed control. Refer to herbicide residue section for information on rotational crop restrictions. Spray solution incompatibility (thickening) may develop if Assert is tank-mixed with dicamba or amine formulations of 2,4-D or MCPA. Thickening results from using hard water, or additives that increase spray solution pH. Assert 2.5S is formulated as a sulfate ester, is water soluble only at a low pH, and contains chemicals to keep the pH low. The amount of acidifier in the formulation may be inadequate when rates are low or when highly alkaline waters are used or in a mixture with other herbicides or fertilizers that raise pH. These conditions may cause Assert to precipitate and reduce efficacy as well as plug nozzles. Amine formulations of 2,4-D, MCPA, or dicamba impart a high pH to the spray solution and can cause Assert to precipitate even when the spray water is neutral. To reverse thickening, lower water pH by adding an acid, preferably muriatic acid (HCl). Muriatic acid is available at most agricultural outlets and comes in different concentrations (10% HCl to 100% HCl). Regardless of concentration add only enough to change the solution to a liquid state (less than 1 gal/100 gal water when using a 10% HCl conc.) B7. Axial XL (pinoxaden, "den" class) at 16.4 fl oz/A or Axial at 8.2 fl oz/A plus Adigor adjuvant at 9.6 fl oz/A controls wild oat, green and yellow foxtail, Persian darnel, annual ryegrass and suppresses barnyardgrass in HRS, winter wheat, and barley. Apply to crop from 2-leaf until prior to flag leaf emergence and to 1-leaf to 2-tiller grass weeds. Axial is an ACCase inhibitor herbicide, which has the same mode of action as Achieve, Discover, and Puma but Axial has controlled some but not all ACCase-resistant wild oat biotypes. Axial can be tankmixed with most broadleaf herbicides labeled in small grain. Refer to label for tank-mix options and application information. B8. Bromoxynil applied POST controls kochia, wild buckwheat, fumitory and other annual broadleaf weeds in wheat, barley, and oat from crop emergence to early boot. See label tank-mix options. For increased weed control, bromoxynil + MCPA ester should be applied from the 3-leaf to early boot stage. Several commercial products are available. Bromoxynil & 2,4-D premixes are similar to bromoxynil + MCPA but may provide better control of redroot pigweed, wild buckwheat, Russian thistle, and larger weeds. Formulation, application rate and stage are specific for each formulation. Refer to label for use information. Some labels include use on tame oat; however, oat grown in ND has shown more potential to injury from 2,4-D because of environmental conditions and is not recommended. B9. Chlorsulfuron at 1/6 to 1/3 oz DF/A or Finesse (chlorsulfuron & metsulfuron) at 2/10 to 4/10 oz DF/A with 2,4-D or 2,4-D + dicamba applied POST will control most annual weeds and suppress Canada thistle, and at 3/10 to 4/10 oz DF/A will suppress and/or control green foxtail in spring wheat and barley. Follow label for application window and tank-mix herbicides. Apply with NIS at 0.125% v/v depending on the tank-mix herbicide and rate. Finesse can be applied only once every 24 months in North Dakota. Speed at which weeds are killed is relatively slow compared to other SU herbicides. B10. Clopyralid & 2,4-D at 2 to 2.33 pt/A or clopyralid & MCPA at 1.75 to 2.33 pt/A controls Canada thistle and annual broadleaf weeds in barley, durum, and hard red spring wheat. Canada thistle is most susceptible at rosette to early bolting stages. Curtail will not provide long-term control of Canada thistle with one application but will reduce populations with repeated use. Curtail contains 2,4-D and should be applied to wheat and barley from 4-leaf through jointing only. Do not apply Curtail on oat. See herbicide residue section for recropping restrictions. WideMatch/generics (clopyralid & fluroxypyr) at 1 to 1.33 pt/A controls most broadleaf weeds, including herbicide resistant kochia, and volunteer flax. Field bindweed may be suppressed. Apply from the 3-leaf stage to flag leaf emergence in oat, barley, durum, and hard red spring wheat. Apply to weeds up to the 4-leaf stage or vining. Canada thistle is most susceptible at rosette to early bolting stages. WideMatch will not provide long-term control of Canada thistle with one application but will reduce populations with repeated use. All POST grass herbicides labeled in small grains can be applied with WideMatch. Apply with MCPA, 2,4-D, or thifensulfuron + tribenuron to obtain additional wild mustard, redroot pigweed, common lambsquarters, and Russian thistle control. Allow a 40 day PHI. See label for crop rotation restrictions. Starane (fluroxypyr) at 0.5 to 0.67 pt/A controls kochia (including ALS and dicamba resistant kochia), cleavers, cocklebur, common mallow, ragweed, sunflower, Venice mallow, volunteer flax, and suppresses field bindweed in wheat, barley, and oat. Starane is very effective on kochia and has benefits over dicamba that include excellent wheat, barley, and oat safety; a much wider application window in small grains that extends to flag leaf emergence; control of larger kochia at in-crop use rates; and all POST grass herbicides registered for small grains can be applied with Starane. Starane at 0.5 pt/A controls kochia less than 4 inches tall and 0.67 pt/A controls kochia up to 8 inches tall while bromoxynil only controls small kochia less than 2 inches tall. Starane is not intended to be used alone. Apply Starane with 2,4-D or MCPA for broad-spectrum broadleaf weed control. Starane is labeled with most POST grass herbicides registered in wheat. Refer to label of tank-mix partner for mixing options. Starane is available in several commercial premixes. B11. Dicamba at 0.125 to 0.25 pt/A controls kochia, buckwheat, smartweed, and other broadleaf weeds in wheat, barley, and oat. Dicamba can be applied alone but usually is applied with other herbicides such as MCPA, 2,4-D, and SU herbicides to increase control of wild mustard and other annual and perennial broadleaf weeds. Oat is more tolerant than wheat to dicamba. Apply to wheat and oat at the 2- through 4-leaf stage. Barley can be treated during the 2- through 3-leaf stage but tolerance is marginal. Allow 45 days/pt of dicamba for degradation, excluding days when ground is frozen. B12. Discover/Discover NG (clodinafop + safener) at 3.2 fl oz/A plus DSV at 10.2 fl oz/A or Discover NG at 12.8 fl oz/A controls wild oat, barnyardgrass, volunteer corn, and green and yellow foxtail. Discover at 4 fl oz/A plus DSV at 12.8 fl oz/A or Discover NG at 16 fl oz/A controls giant foxtail, Persian darnel, and annual ryegrass. Apply to actively growing grasses in the 1- to 6-leaf stage. Apply Discover to wheat from the 2-leaf stage to pre-boot. Do not apply to winter wheat in the fall. Discover NG contains 0.5 lb ai/gal, includes the adjuvant in the formulation, requires no additional adjuvant, but allows MSO to be added at 0.25% v/v to improve yellow foxtail, Persian darnel, and ryegrass control. Discover controls grass weeds over wide environmental conditions and when applied with several broadleaf herbicides. See label for approved tank-mix options. B13. Everest (flucarbazone) at 0.3 oz WDG/A controls green foxtail and at 0.4 to 0.6 oz WDG/A controls wild oat and suppresses yellow foxtail, downy brome, and Japanese brome in all types of wheat. Everest may be applied at burndown at up to 0.4 oz/A prior to spring or winter wheat. Use high rates to control yellow foxtail, barnyardgrass, downy brome, Persian darnel, and for high grass weed densities. Apply with NIS at 0.125% when applying with SU herbicides. Do not add any adjuvant when an emulsifiable concentrate (EC) pesticide is included in the tank-mix. Up to 50% of the carrier volume may be liquid nitrogen when applied to winter wheat. Apply in at least 5 gpa by ground to actively growing grass weeds in wheat from emergence to prior to jointing. Everest controls mustard species, annual smartweed, and redroot pigweed. Uptake is primarily foliar but soil residue absorbed by roots may give 2 to 4 weeks residual control of highly susceptible species when the soil pH is 7.2 or higher, depending on rainfall, temperature, and organic matter. 2,4-D or dicamba is required for safening when tank-mixing with SU herbicides. Dicamba may reduce wild oat control. Most crops may be planted the year following application. See label for crop rotation restrictions. B14. Far-Go (triallate) at 1 to 1.5 qt/A or 10 to 15 lb 10G applied preplant or PRE incorporated (depending on formulation) controls wild oat in wheat, durum, barley, lentil, or pea. See tables for specific rates. Far-Go is volatile and the liquid formulation must be incorporated immediately after application. Spring-applied liquid formulations has given more consistent wild oat control with less crop thinning than the granular formulation. See section on fall application. Far-Go at 1 qt/A may be applied after seeding in combination with trifluralin at 1 to 1.5 pt/A for both wild oat and foxtail control in wheat, durum, and barley. Far-Go will control wild oat with a shallow incorporation. Two spike tooth harrowings at right angles will incorporate Far-Go. Deeper incorporation enhances wild oat control from Far-Go. Far-Go applied after seeding (PoPI) should be incorporated less deeply than the depth of the crop seed. Far-Go applied before seeding should be incorporated with a field cultivator plus harrow operated 3 to 4 inches deep. Delay wheat seeding for 3 days. Far-Go applied before seeding may injure certain wheat varieties. Spring PPI Far-Go has greater potential for injury to wheat than when applied at other times. Refer to label for varieties that may be susceptible to PPI Far-Go. B15. Huskie (bromoxynil & pyrasulfotole & mefenpyr safener) at 11 to 15 fl oz/A controls most annual broadleaf weeds, including mustard species, pigweed species, common lambsquarters, wild buckwheat, sunflower, nightshade, kochia, Russian thistle, false chamomile, cleavers, cockle species, chickweed, prickly lettuce, horseweed, and annual and perennial sowthistle in wheat, barley, and triticale. Huskie will not control grass weeds. Apply from 1-leaf to flag leaf emergence. No additional adjuvants are required but AMS at 0.5 lb/A or UAN at 1 to 2 qt/A will optimize broadleaf weed control. Huskie can be applied with POST grass herbicides, fungicides, and insecticides and most crops can be planted the year following application. Refer to label for other information. Bromoxynil and pyrasulfotole both act at different sites in the photosynthetic pathway and will control broadleaf weeds resistant to other herbicides. B16. Maverick (sulfosulfuron) at 0.67 oz DF/A applied fall POST controls cheat, downy brome, and Japanese brome at 2- to 3-leaf stage in winter wheat or applied spring POST suppresses annual bromes with less than 5-tillers. Maverick at 0.67 oz DF/A applied spring POST controls wild oat in the 1- to 4-leaf stage and may also control cleavers, false chamomile, flixweed, annual smartweed species, mustard species, quackgrass, and sunflower. Apply Maverick with NIS at 0.5% v/v. Maverick may be applied with most herbicides labeled in wheat. Maverick should be applied with another broadleaf herbicide with a different mode of action to prevent weed resistance. Maverick will not control ALS resistant weeds. Do not apply Maverick with organophosphate insecticides. Maverick spray drift or sprayer contamination causes severe injury to most broadleaf crops. Thoroughly clean sprayer to prevent injury to susceptible crops. See sprayer cleanout section. Maverick may persist in soil for 3 years or more. Refer to label or carryover section for recropping restrictions. B17. Metsulfuron at 1/10 oz DF/A or metsulfuron & thifensulfuron & tribenuron at 0.2 to 0.4 oz DF/A applied POST controls broadleaf weeds in wheat and barley and should be applied with another broadleaf herbicide with a different mode of action to reduce development of resistant weeds. Burndown (speed of weed death) is faster with Ally and Ally Extra than other SU herbicides. Apply with NIS at 0.125% v/v depending on the tank-mix herbicide and rate. Do not apply to soils with a pH greater than 7.9. Metsulfuron residue may persist in the soil for 3 years or more. Refer to the herbicide residue crop rotation restriction section. B18. Olympus (propoxycarbazone) at 0.6 to 0.9 oz WDG/A controls wild oat, foxtail barley, mustard species, and suppresses quackgrass, downy brome, and Japanese brome in spring and winter wheat. Apply to 2-leaf to jointing wheat and 2-leaf to 2-tiller grass weeds. Apply with NIS at 0.25 to 0.5% v/v. Fall/spring applications control cheat. Spring applications control wild oat. Silverado (mesosulfuron) at 1.75 to 2.25 oz DF/A controls wild oat, mustard species, and volunteer canola in wheat. Apply from 1-leaf to jointing stage and to 1- to 2-tiller wild oat. Apply with an MSO adjuvant at 1.5 pt/A or basic pH blend adjuvant at 1% v/v or 0.8 to 1.6 pt/A. The MSO should contain at least 10% emulsifier and the basic pH blend adjuvant should consist of a NIS plus fertilizer or MSO plus fertilizer adjuvant formulation. Refer to label for tank-mix options. Silverado will control most ACC-ase resistant wild oat populations. Do not apply with malathion, methyl parathion, or mancozeb to avoid crop. Most crops can be planted the year following application; see label or herbicide carryover section. Rimfire (mesosulfuron + propoxycarbazone) at 1.75 to 2.25 oz DF/A controls wild oat, mustard species, and volunteer canola, and suppresses green and yellow foxtail, barnyardgrass, downy and Japanese brome, Persian darnel, foxtail barley, quackgrass, chickweed, catchweed bedstraw, henbit, and redroot pigweed in wheat. Rimfire at 1.75 to 2.25 oz/A + Silverado at 0.5 oz/A will provide optimum control of Persian darnel. Apply from 1-leaf to flag leaf emergence. Apply with an MSO adjuvant at 1.5 pt/A, basic pH blend adjuvant at 1% v/v, or NIS at 0.25 to 0.5% v/v + UAN at 1 to 2 pt/A. Rimfire contains the full labeled rate of Silverado and a low rate of Olympus. Refer to label for tank-mix options. Rimfire will control most ACC-ase resistant wild oat populations. Most crops can be planted the year following application. See label for tank-mix options, crop rotation restrictions and application information. B19. Paramount (quinclorac) at 0.33 lb 75DF/A with MSO type adjuvant at 1.5 pt/A postharvest to any crop on land to be planted the following year to wheat, including durum, controls some broadleaf weeds including field bindweed. Wheat and sorghum have a 0 hour plant back restriction. Paramount at 0.17 to 0.33 lb DF/A controls green foxtail, yellow foxtail, barnyardgrass, cleavers/bedstraw, volunteer flax, and may suppress small kochia and Russian thistle. Refer to label. Paramount is one of the most effective herbicides on field bindweed. Apply Paramount with another broadleaf herbicide, such as 2,4-D, MCPA, or ALS herbicides, to broaden spectrum of weeds controlled. Refer to label for application and use directions. B20. Peak (prosulfuron) at 0.25 to 0.5 oz 57DF/A applied POST controls broadleaf weeds in wheat, barley, oat, rye, triticale, proso millet, and sorghum. Apply with another broadleaf herbicide with a different mode of action to prevent weed resistance. Burndown (speed of weed death) is relatively average compared with other SU herbicides. Apply Peak with an NIS. Do not apply a foliar or soil organophosphate insecticide within 15 days before or 10 days after Peak. Corn is tolerant to Peak, which is different than other long residue SU herbicides labeled in small grains. Peak may persist in the soil for 3 years or more. Refer to label or herbicide carryover section for rotational cropping restrictions. B21. Puma (fenoxaprop-P + mefenpyr safener) at 0.33 pt/A controls green foxtail, foxtail millets, and volunteer corn; at 0.4 pt/A controls yellow foxtail and proso millet; and at 0.67 pt/A controls barnyardgrass and wild oat in wheat (including durum) and barley. Puma does not contain phenoxy type herbicides for broadleaf weed control. Apply at 5 to 10 gpa by ground or 5 gpa by air. Use 5 gpa only on light infestations, small weeds, and during good growing conditions. Apply Puma to wheat and durum from 1-leaf until 60 days prior to harvest and to barley from 1-leaf up to 5-leaf stage of growth. Do not apply Puma to jointed barley; to avoid potential injury, terminate application at 4-leaf barley. Puma will control grass weeds in the 1-leaf to 2-tiller stage. Low humidity and high temperature can influence foxtail and wild oat control. Puma can be applied with Mancozeb, Stratego, Tilt fungicides; and Peak, clopyralid, clopyralid + MCPA, Starane, WideMatch, or MCPA ester herbicides at all rates of Puma. Other broadleaf herbicides listed for tank-mix applications with Puma may antagonize wild oat and yellow foxtail control. For green foxtail and foxtail millet control, apply Puma at 0. 33 pt/A with Amber, bromoxynil, bromoxynil + MCPA, clopyralid, clopuralid + MCPA, dicamba, MCPA ester, metsulfuron, thifenfensulfuron, tribenuron, thifensulfuron + tribenuron, Starane, or Stinger. For yellow foxtail and wild proso millet, apply Puma at 0.4 pt/A with clopyralid, clopyralid + MCPA, dicamba, MCPA ester, Peak, or Starane. For barnyardgrass and wild oat control apply Puma at 0.66 pt/A with bromoxynil, bromoxynil + MCPA, clopyralid, clopyralid + MCPA/2,4-D, MCPA ester, Peak, Starane, thifensulfuron, and thifensulfuron + tribenuron. Do not apply Puma to corn, tame oat, or rye. Do not apply Puma within 60 days of wheat harvest or 57 days of barley harvest. B22. Thifensulfuron & tribenuron 1:1 ratio at 4/10 to 8/10 oz SG/A or 4:1 ratio at 6/10 to 1 oz SG/A applied with 2,4-D or 2,4-D + dicamba controls most broadleaf weeds in wheat and barley. Apply with NIS at 0.25 to 0.5% v/v. Even though the soluble granule (SG) formulations are easier to clean from spray equipment than previous formulations, thorough cleaning is required to avoid contamination of subsequent spray mixtures and injury to susceptible crops (A8). The 1:1 ration at 0.4 to 0.8 oz SG/A contains the same amount of tribenuron as Express. Apply to broadleaf weeds, including Russian thistle, volunteer RR canola, and Canada thistle, and when antagonism of POST grass herbicide is not important. The 4:1 ratio at 0.6 to 1 oz SG/A contains a similar amount of thifensulfuron as Harmony Extra but the amount of of tribenuron is reduced. Tribenuron antagonizes ACCase POST grass herbicides more than thifensulfuron. Apply the 4:1 ration for wild buckwheat, redroot pigweed, sunflower, and voluteer RR canola control and when tank-mixing with POST grass herbicides in small grains. B23. Trifluralin at 1 pt/A of a 4 lb/gal concentrate or 5 lb/A 10G applied after spring seeding and harrow incorporated shallowly is labeled for control of foxtails in wheat and barley. Use the lower rate on coarse textured soils and the higher rate on fine textured soils. Incorporate by harrowing twice at right angles and depth of herbicide incorporation must be above the wheat seed. Wheat should be seeded 2 to 2.5 inches deep to permit incorporation above the seed. Some wheat varieties, especially semi-dwarfs, emerge poorly from deep seeding so seed should be placed no deeper than 2 to 2.5 inches. A heavy rain or irrigation immediately after trifluralin application has caused wheat injury on light and medium textured soils. Trifluralin applied in this manner does not control wild oat. (See wild oat section for discussion on trifluralin-triallate combination). Trifluralin at 1 pt/A or 5 lb/A 10G may be fall applied for foxtail control on ground to be planted to wheat or barley the following spring. Some stand reduction may occur from fall applied trifluralin but generally no yield loss occurs. Trifluralin is available in both liquid and granular formulations. Granular formulations may be applied to standing stubble; liquid or granular formulations may be used when residue will not interfere with incorporation. Seed wheat or barley no more than 2 inches deep into a moist seedbed. Refer to the chemical fallow section for information on trifluralin applied in the fallow year for foxtail control in small grains the next year. B24. Beyond (imazamox) at 4 fl oz/A or ClearMax (imazamox + MCPA) at 4 fl oz/A + 8 fl oz/A controls wild oat, foxtail, downy brome, Japanese brome, Persian darnel, and many annual broadleaf weeds in Clearfield wheat from 1-leaf to jointing. Apply with NIS at 0.25% v/v. Beyond will not control ALS resistant weed populations. Refer to label for tank-mix options, crop rotation restrictions, and other application and use information. B25. Small grain preharvest herbicides can desiccate weeds and crop and provide perennial weed control. Expectations for preharvest weed control may exceed reality. It is difficult to kill or dry down a 3-foot weed in the same manner as a 3-inch weed. Lower portions of the weed may not be affected. Plant desiccation requires 7 to 10 days, or more when wet and cool conditions persist after treatment. All herbicides labeled for preharvest application are translocated and slow acting which requires a longer dry down period as compared to contact type herbicides like bromoxynil or paraquat. The intent of a preharvest treatment should be to facilitate harvest and reduce harvest loss. Preharvest treatments do not decrease yield losses due to weed competition or prevent weed seed production. Herbicide drift from preharvest treatments can cause injury to crops nearby. Consider sensitive crops (sugarbeet, potato, etc.) and other plants (trees, gardens, etc.) in the general vicinity of the field receiving treatment. No herbicides are labeled as a harvest aid for oats. Paraquat is NOT labeled as a harvest aid in small grains. B26. 2,4-D as a Harvest Aid Apply 2,4-D at 1.5 to 3 pt/A to aid harvest of spring wheat, durum, barley, and rye. Labels vary in crop use. Follow the label. Not all 2,4-D formulations are labeled for preharvest applications. Some 2,4-D labels only allow use on wheat, others allow use on wheat and barley and others allow use on wheat, barley, and rye. Ester formulations will give better control and quicker burndown than an amine formulation. Use at least 2 pt/A of amine formulation for larger weeds. 2,4-D does not control kochia or large pigweed, and wild buckwheat. Weeds with large stems may not burn down and may stay green. 2,4-D can be tank mixed with glyphosate on spring wheat and durum for additional broadleaf and grass control. Follow the glyphosate label. B27. Ally + 2,4-D as a Harvest Aid Ally is labeled as preharvest aid in wheat, durum, and barley alone or with 2,4-D or on wheat and durum with 2,4-D and/or dicamba. Ally has a long residue so use only in a continuous wheat or wheat-fallow rotation. The user must follow crop rotation restrictions. Apply Ally at 0.1 oz DF/A + 2,4-D at 1.5 to 3 pt/A to wheat, durum, and barley in the dough stage and at least 10 days prior to harvest. Do not use if crop was treated previously with another SU herbicide. For wheat, Ally + 2,4-D can be tank-mixed with dicamba for faster dry down and for weed resistance management. Follow the label for crop rotation restrictions and refer to the 2,4-D and/or dicamba label for grazing restrictions. B28. Dicamba + 2,4-D as a Harvest Aid Dicamba can be applied alone or with 2,4-D in wheat and durum to aid harvest. Apply dicamba at 0.5 pt/A + 2,4-D at 1 to 2 pt/A when wheat is in the hard dough stage and the green color is gone from the nodes of the stem. Dicamba will provide additional control of wild buckwheat, kochia, common lambsquarters, pigweeds, sunflower, and Russian thistle as compared to 2,4-D alone. Allow a 7 day PHI for dicamba but 2,4-D formulations may be more restrictive. Always follow the longest PHI of the herbicide used. Do not feed treated straw to livestock. Caution: Drift to broadleaf crops is especially hazardous at this time. B29. Glyphosate as a Harvest Aid Glyphosate is labeled as a harvest aid only in spring wheat, durum, and feed barley. Glyphosate at 0.5 to 2 pt/A of a 3 lb ae/gal concentrate controls annual grass and broadleaf weeds, quackgrass, and Canada thistle. DO NOT apply to wheat or barley grown for seed, or malting barley as a reduction in germination or vigor may occur. Glyphosate drift will injure or kill sensitive plants. Glyphosate should be applied after the hard dough stage (30% or less grain moisture) of wheat and at least 7 days prior to harvest by air or ground in 3 to 10 gpa spray volume. See label for adjuvant use. Always add AMS. AMS increases control of annual and perennial weeds, especially control of weeds stressed by dry weather. AMS also eliminates antagonism from ions and carbonates in hard water. DO NOT use AMS in place of a NIS. Refer to label for addition of other adjuvants Glyphosate can be tank mixed with 2,4-D for additional broadleaf control. Glyphosate at 0.75 to 2 pt/A + dicamba at 0.25 to 0.5 pt/A can be applied preharvest to wheat and durum at the hard dough stage after green color is gone from nodes. Allow a 14 day PHI. The tank-mix can be applied by ground or air. B30. Glyphosate + 2,4-D as a Harvest Aid Glyphosate + 2,4-D controls annual grass and broadleaf weeds, quackgrass, and suppresses Canada thistle in hard red spring wheat, durum, and feed barley only. Refer to label for rate of each formulation. See paragraph above on glyphosate for application information. Apply after the hard dough stage (30% or less grain moisture) of wheat and at least 7 days prior to harvest. DO NOT apply to wheat or barley grown for seed, or to malting barley as a reduction in germination or vigor may occur. Be aware of the injury potential of glyphosate drift on sensitive plants.
CORN C1. A combination of cultural, mechanical and chemical methods
is necessary for effective weed control in corn. Control early
germinating weeds by cultivation or land preparation before
planting if conventional tillage is used. A rotary hoe can be used
to control emerging weeds when the corn coleoptile is below the
working depth of the rotary hoe or when corn is beyond the spike
stage. Cultivate between the rows soon after weeds emerge.
Corn is very susceptible to early season competition from weeds.
Initial postemergence herbicides must be applied before weeds
reach 4 inches in height to avoid yield loss. C2.
NDSU MICRO-RATE PROGRAMS: Stout is lower cost than Accent but cannot be applied beyond 16
inch tall corn. Early application to small weeds minimizes weed
competition with corn and gives greater weed control from
reduced herbicide rates. NDSU research has shown Accent,
Steadfast, and Stout applied half to full rates plus atrazine at
0.42 lb DF/A + dicamba at 4 fl oz/A + MSO type oil or basic pH
blend adjuvants or Lumax at 3 pt/A + PO adjuvants control most
annual grass and broadleaf weeds. Use the highest labeled rate of Accent, Steadfast, and Stout to
control yellow foxtail, wild proso millet, volunteer cereals, field
sandbur, and quackgrass. Apply before grasses are taller than 2
or 3 inches because control will quickly decline. Yellow foxtail
has increased in ND. Dicamba, and especially Distinct,
antagonizes yellow foxtail control from Steadfast and Accent. In
some cases, MSO adjuvant has overcome yellow foxtail
antagonism from dicamba. Atrazine at 0.38 lb ai/A will allow all
crops to be planted the following year, unless severe drought
occurs in the year of application. MSO adjuvants should be used,
when allowed by label, to provide maximum enhancement of
weed control. Refer to C5 below for additional information. NDSU
research has shown enhancement of yellow foxtail control when
Accent, Steadfast, and Stout are applied with Callisto at 3 fl oz/A
+ atrazine at 0.38 lb ai/A + MSO or Lumax at 3 pt/A + oil
adjuvant. C3. Accent (nicosulfuron) at 0.67 oz 75DF/A applied POST to
corn up to 20 inches tall with 6 collars or less or with drop
nozzles to corn 20 to 36 inches tall (free standing). Do not apply
to field corn taller than 36 inches or with 10 collars, whichever is
most restrictive. Resolve (rimsulfuron) at 0.75 to 1 oz DF/A applied POST to corn
up to 12 inches tall and with less than 5 collars controls most
annual grasses, quackgrass, and some broadleaf weeds. Refer
to Steadfast paragraph for additional information. Resolve
(rimsulfuron) as compared to Accent (nicosulfuron) has greater
POST activity on grass weeds, shorter chemical residual in the
soil but greater biological and residual soil activity on weeds, and
has a greater risk of causing injury to short-season corn
varieties. Resolve may add short-term residual weed control
after activation. Steadfast (nicosulfuron & rimsulfuron) at 0.75 oz DF/A or Stout
(nicosulfuron & thifensulfuron) at 0.75 oz DF/A applied POST to
corn up to 12 inches tall and with less than 5 collars controls
most annual grasses, quackgrass, and some broadleaf weeds.
Always add an oil adjuvant at 1.5 pt/A plus nitrogen fertilizer at 1
to 2% v/v or basic pH blend adjuvants at 1% v/v. NDSU research
has shown that adjuvant enhancement of Accent, Steadfast or
Stout was greatest with an MSO type oil or basic pH blend
adjuvant, followed by petroleum oil, and least with NIS + 28%.
Weeds controlled are green foxtail, fall panicum, barnyardgrass,
field sandbur, woolly cupgrass, wild-proso millet, wild oat, quackgrass, pigweed species, smartweed, wild mustard, jimsonweed,
and burcucumber. Poor yellow foxtail control will result if Accent,
Steadfast, or Stout are applied at reduced rates, if applied with
dicamba, if yellow foxtail is larger than recommended, or if growing in
adverse conditions. NDSU research has shown enhancement of
yellow foxtail control when Steadfast or Stout is tank-mixed with
Callisto + atrazine + oil adjuvant at labeled rates or tank-mixed with
Lumax at 3 pt/A. Use caution when applying Steadfast or Stout to
corn hybrids of 88 or less days maturity. See label for herbicide tank-mix options. Do not tank-mix organophosphate insecticides. A soil
residue will be present for more than one year. Refer to the label or
herbicide residue section for crop rotation restrictions. C4. Acetochlor & safener at 1.25 to 2.75 pt/A of a 7EC or at 1.5 to 3
pt/A of a 6.4EC formulation applied PPI or PRE control annual
grasses and certain broadleaf weeds, including pigweed species and
common lambsquarters. Use the higher rate on clay soils high in
organic matter. Do not apply acetochlor on sands with less than 3%
OM, loamy sands with less than 2% OM, or sandy loams with 1% OM
if ground water is within 30 feet of soil surface. Incorporation may
improve weed control under dry conditions. Acetochlor may be
applied up to 45 days before planting and applied POST to corn up to
11 inches tall. Acetochlor applied PPI or PRE provides greater and
more consistent grass and broadleaf weed control than other similar
soil-applied grass herbicides. C5. Aim (carfentrazone) at �� oz 2EW/A applied POST controls small
kochia, lambsquarters, nightshade, pigweed spp. and waterhemp.
Apply Aim to corn up to 8 collar growth stage and to weeds less than
2 inches tall. Apply Aim with NIS at 0.25% v/v and liquid fertilizer.
Petroleum oil adjuvants may increase weed control but also may
increase risk of corn injury. Aim should be applied with another
broadleaf herbicide to broaden spectrum of weeds controls. Aim may
be tank-mixed with most herbicides registered in corn except Liberty.
Refer to label of tank-mix herbicide for tank-mixing options and
adjuvant restrictions. Aim is a non-residual, contact herbicide and
may produce cosmetic injury symptoms of speckling and spotting on
leaves receiving spray. Symptoms should disappear after new growth
appears. Do not apply Aim either 8 hours before or after a rain event
and maintain an 18 inch boom height over corn canopy to minimize
exposure to the whorl of the plant. C6. Atrazine applied PPI or PRE or at rates greater than 0.75 lb ai/A
is not recommend in ND. PPI or PRE atrazine require rates greater
than 1 lb/A for consistent in weed control but also causes carryover
concerns for more than two years. Atrazine is available as a prepackage mix with several herbicides. Most atrazine premixes
contains excessive atrazine rates for normal crop rotation in ND.
Atrazine is a restricted use herbicide. Atrazine at 0.38 to 0.75 lb ai/A applied POST to corn less than 12
inches tall aids in control of broadleaf weeds less than 4 inches tall
and grass weeds less than 1 inch tall. Atrazine controls wild oat,
gives partial foxtail control and excellent control of broadleaf weeds
(including volunteer sunflower) when used in combination with
petroleum oil concentrate or emulsifiable vegetable oil adjuvants. NIS
is less effective with atrazine than any oil adjuvants. Refer to herbicide residue section for carryover precautions. Refer to label for
application information and restrictions. C7. Balance Pro (isoxaflutole) at 1.5 to 3 fl oz/A applied EPP or PRE
controls foxtails, wild proso millet, field sandbur, and woolly cupgrass
and annual small-seeded broadleaf weeds including nightshade,
kochia, pigweed, lambsquarters, common ragweed, wild mustard,
annual smartweed, seedling dandelion, and horseweed (marestail).
Balance may cause corn to turn yellow after emergence but yellowing
may disappear after 3 to 5 days. Balance Pro requires exact mixing,
application, and incorporation to avoid crop injury. Refer to the label
for instructions and information. Use exact rates based on soil type,
pH, and organic matter to insure adequate corn safety. Rates even
slightly greater than labeled for intended soil type, soil pH, and
organic matter can cause slight to serious corn injury. Balance will not control yellow foxtail, wild oat, volunteer grain,
and large-seeded broadleaf weeds like wild buckwheat,
cocklebur, sunflower, giant ragweed. Balance may give 6 to 8
weeks residual weed control after activation. See herbicide
residue section for crop rotation restrictions. Precipitation and
soil moisture are more critical to breakdown than other factors. C8. Basis (rimsulfuron & thifensulfuron) at 0.33 oz 75DF/A
applied POST in corn up to 4-leaf (2 collar) controls small foxtail,
barnyardgrass, redroot pigweed, wild mustard, common
lambsquarters, and annual smartweed. Apply when grasses are
1 to 2 inches tall and broadleaf weeds are 1 to 3 inches tall.
Sequential application of Accent may be needed for complete
weed control. Always apply Basis with an oil adjuvant at 1 to 2%
v/v and nitrogen fertilizer or with basic pH blend adjuvant. Corn
varieties of 88 day maturity or less are more susceptible to injury
from Basis than varieties greater than 88 days. See label for
tank-mix options. C9. Callisto (mesotrione) at 3 fl oz/A plus atrazine at 0.38 lb ai/A
applied POST to corn up to 30 inches tall controls most annual
broadleaf weeds and suppresses Canada thistle. Apply with
petroleum oil adjuvant at 1% v/v + UAN at 2.5% v/v or AMS at
8.5 lb/100 gallons water. NDSU research has shown improved
control of yellow foxtail when tank-mixed with Accent and
Steadfast. Refer to label for crop rotation restrictions. Lumax at 3 pt/A contains 3.2 fl oz/A Callisto & 1 pt/A Dual II
Magnum & 0.38 lb ai/A atrazine and can be applied with POST
grass herbicides labeled in corn. NDSU research has shown
improved weed control, including yellow foxtail control, from
Steadfast + Lumax compared to Steadfast + Callisto + atrazine
at comparable rates. Dual has no POST activity but emulsifiers
in the formulation function as adjuvants to improve weed control.
Refer to label for crop rotation restrictions and other information. Impact (topramezone) at 0.5 to 0.75 fl oz/A plus atrazine at 0.38
lb ai/A applied POST to corn up to 60 inch corn with 6 or less
collars controls most broadleaf weeds. Apply Impact with MSO
adjuvant. Corn has excellent tolerance to Impact. NDSU studies
show that broadleaf weed control from Impact is similar to
Callisto but gives near complete common ragweed and yellow
foxtail control. Impact will leave a residue in the soil the following
year. Soybean, dry bean, canola, flax, safflower, and sugarbeet
cannot be planted for 18 months after application. See label or
herbicide residue section for information on crop rotation
restrictions. Laudis (tembotrione & isoxadifen safener) at 1.5 to 3 fl oz/A plus
atrazine at 0.38 lb ai/A applied POST to corn up V8 stage controls most broadleaf weeds. Laudis will also control yellow
foxtail, barnyardgrass, and proso millet. Always apply Laudis with
either MSO adjuvant at 1.25 pt/A plus AMS at 1.5 lb/A or UAN at
1.5 qt/A or PO at 1% v/v plus AMS at 1.5 lb/A or UAN at 1.5 qt/A.
Corn has excellent tolerance to Laudis. Laudis will leave a
residue in the soil the following year. See crop rotation restriction
section for more information. Callisto, Impact, and Laudis are bleaching HPPD inhibitor mode
of action herbicides which symptoms are expressed as white
plant tissue which quickly desiccates. All three herbicides are
enhanced by atrazine and oil adjuvants, have greater activity on
yellow foxtail than green foxtail, will injure corn if appied with
organophosphate insecticides, and have no known resistant
weeds. C10. Dicamba at 0.25 to 0.5 pt/A applied POST to corn from emergence to 8 inches tall controls many broadleaf weeds including
kochia, smartweed, wild buckwheat and volunteer sunflower, and
suppresses Canada thistle. Dicamba can be applied before corn is 3
feet tall or until 15 days before tassel emergence. Drop nozzles
should be used after corn is 8 inches tall to reduce injury when
dicamba is applied with 2,4-D and to reduce drift potential. Yellow
foxtail control may be reduced when dicamba is tank-mixed with
Accent, Steadfast, and Option. Distinct (dicamba & diflufenzopyr) at 4 to 6 oz WDG/A applied
EPOST or POST to corn from 4 to 24 inches tall (corn 4 to 10 inches
tall is prefered) or Status (dicamba & diflufenzopyr & isoxadifen
safener) at 5 oz WDG/A applied at 4 to 36 inch tall corn controls
annual and perennial broadleaf weeds and will suppress foxtail.
Apply with NIS at 0.25% v/v + UAN at 2 qt/A. Refer to paragraph on
dicamba for additional information. Diflufenzopyr inhibits auxin
transport, is synergistic to dicamba and other growth regulator
herbicides, and aids translocation to metabolic sinks and areas of
high metabolic activity, such as growing points of shoots and roots.
Corn injury can occur when corn is stressed by cold conditions prior
to, at, or immediately after application; when Distinct is applied to
corn less than 4 inches tall; by using an oil adjuvant instead of NIS +
UAN; when a less tolerant variety is treated; and by not allowing the
dry product added to the spray solution to totally dissolve. See label
for mixing order and mixing instructions. Yellow foxtail control may be
reduced when tank-mixed with Accent, Steadfast, and Option. C11. Metolachlor or s-metolachlor at 1 to 2 pt/A or Outlook
(dimethenamid-P) at 16 to 21 fl oz/A applied PPI or PRE control
annual grasses and certain broadleaf weeds such as redroot pigweed
and common lambsquarters. Use the higher rate on clay soils high in
organic matter. Incorporation improves weed control. Metolachlor
products may be surface applied or incorporated in the fall after
September 30 but before ground freezes or applied in the spring. S-metolachlor may give greater weed control than metolachlor at
equal product rates. Metolachlor labels (Parallel, Stalwart C, and Me-Too-Lachlor) recommend the same product rates as s-metolachlor
(Cinch, Dual Magnum, and Dual II Magnum). Metolachlor products
contain both isomers of metolachlor (s-metolachlor and r-metolachlor). S-metolachlor is about 33% more active than the r- and
s- form (2 lb ai/A of s-metolachlor = 3 lb ai/A of r- + s-metolachlor).
Syngenta developed a process to deliver only s-metolachlor without
the r- form, thereby reducing the amount of active ingredient needed. Typical rates
Dual II Magnum, others
Me-Too-Lachlor, others
The table above shows the typical rate of s-metolachlor products is
about 1/3 less than the r+s products. These rates provide similar
levels of weed control because of the greater activity of the s-metolachlor form. The Parallel, Stalwart and Me-Too-Lachlor II (half r-
and half s- form) labels recommend the same product rates as Cinch
and Dual/II/Magnum (all s- form). As a consequence the mixed r- and
s-metolachlor products at labeled rates may provide less weed
control than the s-metolachlor products. Under good moisture and
light weed populations, control may be similar but under heavy grass
pressure and limited rainfall often found in ND, higher rates of r+s-metolachlor products would be required to achieve the same level of
control as s-metolachlor products. These r+s metolachlor products
should not be compared on a pint vs pint basis against s-metolachlor. C12. Option (foramsulfuron & isoxadifen safener) at 1.5 to 1.75
oz WDG/A applied POST controls grass and broadleaf weeds,
quackgrass, and top-growth of Canada thistle in corn with no
more than 6 collars. Always apply with an approved MSO type
adjuvant at 1.5 pt/A plus UAN at 1.5 to 2 qt/A. Option applied
with atrazine will antagonize yellow foxtail control when applied
to foxtail greater than 2 inches tall. All crops can be planted the
following year. See label or narrative for tank-mix options and
crop rotation restrictions and additional information. C13. Permit (halosulfuron) at 0.67 to 1.33 oz 75DF/A applied
POST in corn controls nutsedge and some broadleaf weeds
including sunflower, ragweeds, and cocklebur. Apply with NIS or
oil additive. Permit will have a residue in the soil the year
following application. Refer to the label or herbicide residue
section for more information on crop rotation restrictions. C14. Prowl or Prowl H20 (pendimethalin) at 1.8 to 4.8 pt/A EC
controls annual grasses and certain broadleaf weeds such as
redroot pigweed. Prowl must be used only PRE in corn and not
PPI. Do not use Prowl on sands or loamy sands or on soils with
less than 1.5% organic matter. C15. Python (flumetsulam) at 0.8 to 1.33 oz WDG/A applied
EPP, PPI, or PRE will control nightshade, pigweed, ALS
susceptible kochia, lambsquarters, mustards, annual smartweed,
Russian thistle, Venice mallow and lanceleaf sage. Python does
not control grasses. As with all soil applied herbicides, Python
requires rain to activate the herbicide for adequate weed control
and dry weather following PPI and PRE applications will reduce
weed control. High soil pH increases Python activity and
increases rate of herbicide degradation. Some stunting of corn
may occur under poor growing conditions on soils with pH
greater than 8.0. Use the higher rate on fine textured soils with
greater than 3% OM and the lower rates on coarse textured soils
with less than 3% OM. Incorporate into the top 2 inches for PPI
applications. Soil insecticides should be applied in a T-band to
avoid corn injury. Refer to label for tank-mix options. See
Herbicide Residue section for information on crop rotation
restrictions. Hornet (clopyralid-K salt & flumetsulam) applied EPP, PPI, or
PRE at 4 to 6 oz/A is equivalent to 0.05 to 0.07 lb/A of
flumetsulam + 0.13 to 0.19 lb/A of clopyralid. Adjust rate
according to soil type. Hornet (flumetsulam + clopyralid-K salt) at
2 to 5 oz WDG/A applied POST controls most annual broadleaf
weeds and Canada thistle in corn from emergence up to 24
inches tall. Apply with NIS at 0.25% v/v or oil adjuvant at 1% v/v.
Apply with UAN at 2.5% v/v under dry conditions. Hornet does
not control grasses weeds. C16. Starane (fluroxypyr) at 0.67 pt/A controls only kochia
(including ALS and dicamba resistant), common cocklebur,
common mallow, common ragweed, sunflower, Venice mallow,
and suppresses field bindweed in corn. Apply POST as a
preplant/ preemergence burndown in no-till or as an in-crop
treatment from emergence to V5 stage. Refer to label for
application information and restrictions. WideMatch (clopyralid & fluroxypyr) at 1.33 pt/A controls kochia
(including ALS and dicamba resistant), wild buckwheat, Canada
thistle, prickly lettuce, sunflower, common cocklebur, common
ragweed, common mallow, and suppresses field bindweed in corn.
Apply POST to weeds as a preplant/preemergence burndown in no-till corn or as an in-crop treatment from emergence to V5 stage. Can
be applied with atrazine for improved common lambsquarters and
pigweed control. Can be applied with POST grass herbicides
registered in corn. Observe a 90 day PHI. Refer to label for crop
rotation restrictions and other application and use information. C17. 2,4-D amine is not recommended by NDSU on corn because of
the high potential for corn injury and stalks to become brittle and
break off in windy conditions. The safest application stage is EPP or
PRE. Do not apply to corn greater than 8 inches tall. Apply 2,4-D with
drop nozzles when corn is 8 to 24 inches tall to reduce corn injury by
directing the spray away from the whorl. Do not apply MCPA to corn;
it is not labeled and will injure corn. C18. Emergency control of broadleaf and grass weeds in corn can
be obtained with paraquat at 0.8 to 1.3 pt/A applied POST directed
only. Apply with NIS at 0.25% v/v. Paraquat applied over the top of
corn will cause severe injury and contact with the leaves will cause
burning. Do not apply paraquat before corn is 10 inches high. Weeds
should be less than 4 inches tall. CLEARFIELD CORN C19. Lightning (imazethapyr & imazapyr) at 1.28 oz WDG/A controls
nearly all annual grass and broadleaf weeds except ALS resistant
kochia and suppresses quackgrass and Canada thistle. Apply
Lightning only to Clearfield corn varieties and to weeds 1 to 3 inches
tall. Apply with oil adjuvant and liquid fertilizer. Lightning contains
Pursuit and Arsenal, both imidazolinone herbicides. The rate of
Pursuit in Lightning is approximately 1.08 oz WDG/A and Arsenal is
at 1% the rate of Arsenal that is registered on noncropland. Refer to
the rotational crop restriction section of this guide. Use dicamba,
Distinct, or herbicides with a different mode of action or use other
weed control strategies that will slow development of resistant weeds
throughout the rotation. LIBERTY LINK CORN C20. Liberty (glufosinate) at 28 to 34 fl oz/A applied POST to Liberty
Link corn varieties up to 24 inches with 7 or less collars controls most
annual broadleaf weeds, controls or suppresses grasses, and may
suppress some perennial weeds. Liberty is a non-selective, non-residual, contact herbicide. Apply to small weeds because of limited
translocation. Liberty does not control large or well tillered grasses
like yellow foxtail, wild oat, or volunteer cereals. Liberty is non-residual, which may require multiple applications or applying with a
residual herbicide to control multiple weed flushes. Apply with AMS
fertilizer. Refer to label for weeds controlled, application information
and timing, tank-mix options, application information, and other
restrictions. Liberty can be used to control weeds resistant to other
herbicides. Liberty + Define SC (glufosinate + flufenacet) at 28 to 34 fl oz/A + 9
fl oz/A controls many grass and broadleaf weeds. Define increases
control of yellow foxtail. Refer to the Define label for additional
restrictions. ROUNDUP READY CORN C21. Glyphosate at labeled rates in Roundup Ready (RR) corn
up to 30 inches tall with 8 collars or less will control most annual
and perennial weeds. Certain formulations do not require
additional NIS, while others require either partial or full NIS rates.
Add AMS at 2 to 6 lb/100 gal water or at 1 lb/A if applied at less
than 12 gpa to all glyphosate formulations. In-crop application
timing may not be appropriate for effective perennial weed
control. Glyphosate is a non-selective, non-residual, translocated
herbicide that controls grasses at rates as low as 0.25 pt/A.
Labeled rates are required to control broadleaf weeds. However,
some broadleaf weeds like kochia, nightshade, wild buckwheat,
horseweed (marestail), dandelion, amd lambsquarters may not
be controlled by glyphosate applied alone or after one
application. ROUNDUP READY CORN II RR corn II hybrids have increased resistance to glyphosate
compared to RR corn hybrids. Not all glyphosate formulations
contain use information on RR Corn II. Glyphosate brands
allowing application on RR corn II should be applied to RR corn
up to 30 inches or 8 collars at a maximum single application rate
of 0.75 lb ae/A. Glyphosate brands registered for RR corn II can
be applied to RR corn up to 24 inches or 8 collars; or by drop
nozzle application to corn from 24 to 48 inches at a maximum
single application rate of 0.75 lb ae/A for annual weeds and up to
1.125 lb ae/A for perennial weeds. Generic glyphosate brands
can be used on RUR corn II hybrids but application information
and restrictions contained on the label must be followed. Use
glyphosate according to label directions on the glyphosate brand
used and not according to the label on a different glyphosate
brand. Glyphosate is non-residual so multiple applications or combining
with a residual herbicide may be needed to control multiple weed
flushes. Refer to label for weeds controlled, application
information and timing, tank-mix options, and other restrictions. Glyphosate will control weeds resistant to other herbicides. Continue to next page
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