Weed management
Michael W. Marshall
General information
Weed management is an integral part of corn production. Weed management systems should prevent weed interference, be economical and sustainable, reduce the weed seed bank in soil, prevent weed resistance and neither injure corn plants or reduce yield. Weeds compete with corn for moisture, nutrients, and sunlight.
To be successful, weed management systems require advance planning and timely execution. Proper weed identification is essential to selecting the correct herbicide. Any delay in an application may mean reduced control, higher herbicide use rates, greater herbicide costs, and reduced yields.
A successful weed management plan will use multiple methods to keep weed populations low. Tillage and seedbed preparation should eliminate all emerged weeds prior to planting. Components of a weed management system can include many of the following: 1) Early preplant burndown which may contain an herbicide with residual activity; 2) Burndown application at planting which may include a residual herbicide; 3) Postemergence applications with or without a residual herbicide.
The use of mechanical cultivation with rotary hoes, rolling cultivators or sweeps may reduce the need for an herbicide application early in the growing season. Use of specific herbicides depends on the weed spectrum of your field, economic considerations and application system. Consider your situation and tailor a weed control program to your needs. The following sections will guide you in the decision making process.
Atrazine and water quality
Atrazine users are strongly encouraged to follow label guidelines, discussed below, to share in the responsibility of preserving the future use of atrazine. These restrictions apply to all formulations of atrazine, and all package mix products which contain atrazine.
- Mixing, Loading and Application.
Atrazine may not be mixed/loaded or used within 50 feet of all wells, including abandoned wells, drainage wells and sink holes. Atrazine may not be mixed or loaded within 50 feet of intermittent streams and rivers, natural or impounded lakes and reservoirs.
Atrazine may not be applied aerially or by ground within 66 feet of the points where field surface runoff enters perennial or intermittent streams and rivers or within 200 feet around natural or impounded lakes and reservoirs. If atrazine is applied to highly erodible land, the 66-foot buffer or setback from runoff entry points must be planted to corn, seeded with grass, or another suitable crop.
- Application Rates.
Soil applications. Highly Erodible Soils(as defined by NRCS). If conservation tillage is practiced (at least 30 percent residue coverage at planting), apply a maximum of 2 lbs. a.i./acre. If residue coverage is less than 30 percent, apply a maximum of 1.6 lbs. a.i./acre. Soils Not Highly Erodible - Apply a maximum of 2 lbs. a.i./acre.
Postemergence applications. If atrazine was not applied prior to corn emergence, applications of up to 2 lbs. a.i./acre are permitted. If a postemergence atrazine application is required following a preemergence atrazine application do not exceed 2.5 lbs. a.i./acre/calendar year. Postemergence applications to corn must be made before corn exceeds 12 inches in height.
- Weed Management Where Atrazine Can Not Be Used.
Apply a preemergence grass herbicide and follow with postemergence herbicides. – Apply Dual Magnum, Frontier, Outlook, or Prowl H2O (if soybean replanting flexibility is needed) immediately following planting. Select and make timely applications of appropriate broadleaf herbicides for control of cocklebur, annual morningglory, and Palmer amaranth. Follow-up applications may be needed due to lack of residual control.
Plant a ClearfieldTM hybrid, apply a preemergence grass herbicide, and follow with Lightning or Pursuit postemergence. - Apply Dual Magnum, Frontier, Outlook, or Prowl H2O (if soybean replanting flexibility is needed) immediately following planting. Pursuit may be applied preemergence, but overall weed control will be better if applied early postemergence. Pursuit is also registered on soybeans and would provide soybean replant flexibility.
Lightning has a broader weed spectrum than Pursuit, and may be applied postemergence to corn up to 20 inches tall or the V6 stage. Lightning has a 9 month soybean rotation restriction. Follow-up herbicide applications may be needed for late emerging cocklebur.
Plant a Roundup Ready™ or LibertyLinkTM hybrid, apply a preemergence grass herbicide, and follow with glyphosate (Roundup) or glufosinate (Ignite) postemergence. - Apply Dual Magnum, Frontier, Outlook, or Prowl (if soybean replanting flexibility is needed) immediately following planting. Glyphosate may be applied overtop on Roundup Ready corn hybrids from emergence through the V8 stage (8 leaves with collars) or until corn is 30 inches tall.
Ignite 280SL may be applied overtop on LibertyLink corn hybrids from emergence through the V5 growth stage (5 leaves with collars). In fields where glyphosate-resistant Palmer amaranth is a concern, Ignite 280SL will control these biotypes. See respective product labels for additional instructions.
Roundup Ready™ corn
Roundup Ready™ (RR) corn continues to be adopted by many South Carolina growers. The following topics should be considered when planning to grow a RR Corn hybrid.
- Use a soil-applied herbicide. Do not delay making applications with hopes of a single application being sufficient for season-long weed control. Glyphosate will generally need to be applied 2-4 weeks after weed emergence to prevent early-season yield loss from competition. Florida pusley, dayflower, nutsedge, and morningglories are less susceptible to glyphosate and generally require multiple applications or tank mixing with other herbicides for effective control. Use of a soil-applied herbicide will provide greater flexibility in timing of glyphosate applications.
- Use crop rotation or at least rotation of herbicide systems to reduce the potential for development of glyphosate resistance. Roundup Ready™ technology should be used only as a single weed management tool in a toolbox containing many options. Continued use of glyphosate in RR crops will increase the likelihood of selecting for glyphosate resistant weeds (i.e., Palmer amaranth is now resistant to 3 herbicide modes of actions: ALS-inhibitors, dinitroanilines, and glyphosate).
Glyphosate is formulated as a salt, thus making the product highly water-soluble. High concentrations of sodium (Na) salts are common in some South Carolina water sources and may reduce weed control by binding to glyphosate. The addition of 8.5 lbs of ammonium sulfate (AMS) per 100 gallons of water will help overcome this antagonism.
When the spray volume is reduced from 20 to 10 gallons/acre, the number of salt molecules that could potentially interact with glyphosate is reduced by 50%. In addition, spray droplet size will be reduced as spray volume is lowered, concentrating glyphosate molecules within the droplet, facilitating glyphosate movement into the plant via diffusion.
Glyphosate-Resistant Palmer Amaranth management programs for corn
Palmer amaranth (Amaranthus Palmeri S. Wats.) is a dioecious, erect summer annual that may reach 6 1/2 feet in height. Leaves are alternate and occur on relatively long petioles that are longer than the leaves. Small, green, inconspicuous flowers are produced in terminal panicles that are from 1/2 to 1 1/2 feet in length. Smaller lateral inflorescences also occur between the stem and the leaf petioles. Male and female flowers occur on separate plants.
Palmer amaranth populations exist in South Carolina that are resistant to acetolactate synthase (ALS) inhibiting herbicides and dinitroaniline (yellow) herbicides. Recently, glyphosate-resistant Palmer amaranth populations have been confirmed in South Carolina.
The following table is designed to aid producers in managing and/or preventing glyphosate-resistant Palmer amaranth populations in corn.
Seed Program |
Herbicide Program |
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PRE1 |
POST2 |
POST-DIRECTED3 |
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Conventional |
atrazine, Harness, Bicep II Magnum, Cinch ATZ, Guardsman, Lexar |
Banvel, Clarity, Distinct, |
2,4-D, |
No PRE applied |
Buctril + atrazine, Laudis + atrazine, Callisto + atrazine, Impact + atrazine Marksman |
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ClearfieldTM |
atrazine, Bicep II Magnum, Harness, Cinch ATZ, Guardsman, Lexar |
Lightning + Status |
2,4-D, |
No PRE applied |
Lightning + Status |
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Liberty-LinkTM |
atrazine, Bicep II Magnum, Harness, Cinch ATZ, Guardsman, Lexar |
Ignite + Banvel or Clarity, |
2,4-D, |
No PRE applied |
Ignite + atrazine + Callisto |
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Roundup ReadyTM |
atrazine, Bicep II Magnum, Harness, Cinch ATZ, Guardsman, Lexar |
glyphosate + atrazine |
2,4-D, |
No PRE applied |
glyphosate + s-metolachlor + atrazine |
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PRE = Preemergence. Apply to soil surface after all tillage and planting has occurred.
2 POST = Consult individual product labels for corn height restrictions, e.g., atrazine applied POST limited to corn 12 “ or less.
Herbicides for Weed Management in Corn
Preplant/Burndown Herbicides for Weed Management in Corn |
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Rate/Acre Broadcast |
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Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Clarity 4 S Banvel 4 S |
8.0-16 oz |
0.25-0.5 lb |
Apply any time prior to planting corn. Use 16 oz/A rate on medium to fine texture soils with >2.5% organic matter. Use 8 oz/A rate on coarse textured soils with less than 2.5% organic matter. MOA=4 |
Direx 4 L |
0.5-0.8 qt |
0.5-0.8 lb |
Apply anytime from fall through spring prior to planting corn. Heavy textured soils will require higher application rate. DIREX 4L may be tank mixed with other burndown herbicides, consult tank mix partner label for more details. Plant corn at least 1.5” deep and make sure seed slot is closed. Do not replant treated areas to crops other than corn or cotton within 8 months following treatment. Do not apply more than 1.6 qt/A of DIREX 4L per year. MOA=7 |
ET 0.208 EC |
0.5-2.0 oz |
0.0008-0.003 lb |
Field corn may be planted any time after ET application. For best result, apply ET to broadleaf weeds less than 4“ tall or rosettes less than 3“ in diameter. Ground application requires minimum of 10 gallons/A. Do not allow livestock to graze in treated areas. MOA=14 |
Ignite 280 S |
29-36 oz |
0.53-0.66 lb |
Thorough spray coverage is essential for optimum performance. Ground application requires a minimum of 15 gallons of water/acre. Dense weed canopies require 20 to 40 gallons per acre. See label for further application instructions and tank-mix partners. MOA=10 |
Glyphosate 3 lb ae/gal |
32-160 oz |
0.75-3.8 lb ae |
Apply in 10-20 gal of water 2 to 4 weeks prior to your anticipated planting date to control existing groundcover. In most fields, a follow-up application of GRAMOXONE will be needed at planting. Consult product label to determine if a non-ionic surfactant is needed. MOA=9 |
2,4-D |
1.0-2.0 pt |
0.475 lb |
Apply 7 to 14 days prior to planting field corn. Do not use on a light, sandy soil, or where soil moisture is limiting weed growth. Very effective for cutleaf eveningprimrose control. Can be tank-mixed with other burndown herbicides (see label). MOA=4 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Preplant/Burndown Herbicides for Weed Management in Corn (cont) |
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Rate/Acre Broadcast |
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Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Gramoxone Inteon 2 E Gramoxone Max/Firestorm 3 S |
2.0-4.0 pt
1.5-2.0 pt |
0.5-1.0 lb
|
GRAMOXONE is a RESTRICTED USE PESTICIDE. Apply at planting as a follow-up to an earlier application of GLYPHOSATE. Better control of chickweed, henbit, deadnettle and cutleaf eveningprimrose than GLYPHOSATE. Add non-ionic surfactant at 1 qt/100 gal of spray mix. MOA=22 |
Valor SX 51 WDG (flumioxazin) |
2 oz |
0.064 lb |
Apply 14 to 30 days prior to planting field corn. Do not apply more than 3 oz/A of VALOR SX during a single growing season. Do not irrigate when corn is emerging to the 2-leaf stage. Do not use on popcorn, sweet corn, or corn grown for seed. Can be tank-mixed with other burndown herbicides (see label). MOA=14 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Preemergence (PRE) Herbicides for Weed Management in Corn |
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Rate/Acre Broadcast |
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Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Aatrex 4 WDL |
1.6-2.0 qt |
1.6-2.0 lb |
ATRAZINE is a RESTRICTED USE PESTICIDE. Use to control most broadleaf weeds and a few grasses. Tank mix with a grass herbicide for broader spectrum control. MOA=5 |
Acetochlor |
HARNESS is a RESTRICTED USE PESTICIDE. Controls most annual grasses (except Texas Panicum) and some small-seeded broadleaf weeds. ACETOCHLOR can be tank-mixed with ATRAZINE for improved weed control. Available in several pre-mixes with ATRAZINE (DEGREE XTRA, HARNESS XTRA, FULTIME). MOA=15 |
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Harness 7 E |
1.5-3.0 pt |
1.3-2.6 lb |
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Harness 20 G |
6.0-10.0 lb |
1.2-2.0 lb |
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Surpass 6.4 EC |
2.0 pt |
1.6 lb |
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TopNotch 3.2 ME |
2.0-3.0 qt |
1.6-2.4 lb |
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Degree 3.8 ME |
2.25-4.25 pt |
1.06-2.02 lb |
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Alachlor |
2.0-2.75 qt |
2.0-2.75 lb |
MICRO-TECH is a RESTRICTED USE PESTICIDE. Controls most annual grasses (except Texas Panicum) and some broadleaf weeds. ALACHLOR may be tank mixed with ATRAZINE or SIMAZINE. MOA=15 |
Axiom 68 DF (flufenacet |
13-22 oz |
0.55-0.94 lb |
Provides annual grass and small-seeded broadleaf control similar to ACETOCHLOR, ALACHLOR, and METOLACHLOR. May be tank-mixed with ATRAZINE for improved control of broadleaf weeds. Corn and soybeans can be planted any time after an application of AXIOM. MOA=15+5 |
Dimethenamid-p (Outlook 6 EC) |
10-16 oz |
0.47-0.75 lb |
Controls most annual grasses (except Texas Panicum) and some broadleaf weeds. DIMETHENAMID-P may be tank-mixed with ATRAZINE or SIMAZINE. MOA=15 |
Metolachlor |
Controls most annual grasses and some broadleaf weeds. Fair to good control of yellow nutsedge. METOLACHLOR and S-METOLACHLOR may be tank mixed with ATRAZINE. Generic formulations of METOLACHLOR are also available. DUAL II and DUAL II MAGNUM contain a safener that helps reduce the possibility of injury from S-METOLACHLOR applications. MOA=15 |
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Dual 8E/II |
1.5-2.0 pt |
1.5-2.0 lb |
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Dual 25G/II G Mag. |
6.0-8.0 lb |
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S-metolachlor |
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Dual Magnum |
1.0-1.33 pt |
0.96-1.27 lb |
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Dual II Magnum 7.64 EC |
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Cinch 7.64 EC |
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1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Preemergence (PRE) Herbicides for Weed Management in Corn (cont) |
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Rate/Acre Broadcast |
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Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Bicep II Magnum 5.5 SC |
1.3-2.1 qt 0.8-1.33 pt |
0.78-1.27 lb |
BICEP II MAGNUM is a RESTRICTED USE PESTICIDE. Application rate is based on soil type: Sandy soils = 1.3-1.6 qt/A, Medium textured soils = 1.6-2.1 qt/A. Use higher rate for each soil type if applying in a reduced tillage system. Available as a pre mix with glyphosate (EXPERT). MOA=15+5 |
Bullet 4 ME (alachlor |
2.5-3.75 qt
1.56-2.34 qt |
1.56-2.34 lb |
BULLET and LARIAT are RESTRICTED USE PESTICIDES. Application rate is based on soil type and organic matter: Sandy soils = 2.5-3.0 qt/A, medium textured soils = 3.0-3.75 qt/A. Use higher rate for each soil type if applying in a reduced tillage system. MOA=15+5 |
Cinch ATZ 5.5 SC (s-metolachlor |
2.6-3.2 pt 0.8-1.0 pt |
0.78-0.96 lb |
CINCH ATZ is a RESTRICTED USE PESTICIDE. Application rate is based on soil type: Sandy soils = 2.6 pt/A, medium textured soils = 3.2 pt/A. MOA=15+5 |
Degree Xtra 4.04SC |
2.9-3.7 qt 4.1-5.3 pt |
1.94-2.5 lb |
DEGREE XTRA is a RESTRICTED USE PESTICIDE. Application rate is based on soil type: Sandy soils = 2.9 qt/A, Medium textured soils = 2.9-3.74 qt/A. Use higher rate for each soil type if applying in a reduced tillage system. MOA=15+5 |
FulTime 4 SC (acetochlor |
2.5-3.3 qt 1.9-2.25 qt |
1.52-1.8 lb |
FULTIME is a RESTRICTED USE PESTICIDE. Application rate is based on soil type: Sandy soils = 2.5-3.0 qt/A, Medium textured soils = 2.7-3.3 qt/A. Use higher rate for each soil type if applying in a reduced tillage system. MOA=15+5 |
Harness Xtra 5.6 L (acetochlor |
1.4-2.6 qt 1.25-1.5 pt |
1.09-1.31 lb |
HARNESS XTRA is a RESTRICTED USE PESTICIDE. Application rate is based on soil type: Sandy soils = 1.4-1.7 qt/A, Medium textured soils = 1.7-2.6 qt/A. Use higher rate for each soil type if applying in a reduced tillage system. MOA=15+5 |
Lumax 3.95 EC (s-metolachlor |
2.5 qt 1.6 pt 1.25 pt 0.58 oz |
1.68 lb 0.625 lb 0.018 lb |
LUMAX is a RESTRICTED USE PESTICIDE. Apply LUMAX preemergence after planting or as a preplant treatment 14 days before planting. If applied as a preplant burndown, include GLYPHOSATE for broader spectrum weed control. Up to 0.82 lb of ATRAZINE may be applied postemergence. MOA=15+5+28 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Preemergence (PRE) Herbicides for Weed Management in Corn (cont) |
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Rate/Acre Broadcast |
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Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Princep 4 WDL |
2.0-2.5 qt |
2.0-2.5 lb |
PRINCEP is a RESTRICTED USE PESTICIDE. Similar to ATRAZINE but requires more rainfall for activation and is generally less effective in control of certain broadleaf weeds. Good control of crabgrass and fall panicum. SIMAZINE may be tank mixed with ATRAZINE, ALACHLOR, or METOLACHLOR. MOA=5 |
Prowl H2O 3.8 CS Prowl 3.3 EC + |
1.55-3.13 pt
1.8-3.6 pt + |
0.74-1.49 lb
0.74-1.49 lb + |
Do not apply preplant incorporated or serious corn injury can result. Plant corn at least 1.5 in. deep. Corn seed must be completely covered with soil. Apply after planting before emergence of weeds. Use the higher rates on fine-textured soils. In case of stand failure, corn seed should be replanted below the herbicide treated zone. Add ATRAZINE at 1.0 to 2.0 qt/A for control of broadleaf weeds. MOA=3+5 |
Python 80 WDG |
1.0 oz |
0.05 lb |
For areas where ATRAZINE cannot be used or in fields subject to flooding where soybeans may be re-planted. Plant corn at least 1.5" deep. Mix with a preemergence grass herbicide and apply on the surface. Good to excellent control of Palmer amaranth, sicklepod, and cocklebur. Do not apply where COUNTER or THIMET insecticides are to be used. Other corn insecticides should be applied in a T-band to avoid injury. Do not plant cotton within 18 months of application. MOA=2 |
Resolve 25 DF |
0.5-2.0 oz |
0.008-0.031 lb |
Control most annual grasses and broadleaves including broadleaf signalgrass. For control of emerged weeds at application, add NIS at 1 qt/100 gal or COC at 1 gal/100 gal of spray solution plus 2 qt/A of UAN (28-32% N) or 2 lb/A of spray grade AMS. MOA=2 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Postemergence (POST) Herbicides for Weed Management in Corn.
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Rate/Acre Broadcast |
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Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
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Accent 75 DF NIC-IT 2 EC |
0.67 oz
2.0 oz |
0.031 lb |
Apply overtop or with drop nozzles to control rhizome johnsongrass 8 to 18" tall. ACCENT or NIC-IT may be applied overtop corn up to 20" tall (V5), whichever is most restrictive. Add NIS at 1 qt/100 gal or COC at 1 gal/100 gal of spray mix plus 2 qt/A of UAN or 2 lb/A of AMS. Do not apply ACCENT or NIC-IT to corn previously treated with COUNTER 15G, or COUNTER 20CR (in-furrow) unless hybrid is IR (imidazolinone resistant). Injury may occur when ACCENT or NIC-IT is applied to corn previously treated with soil-applied THIMET, LORSBAN or COUNTER 20CR T-banded. Note: In fields heavily infested with johnsongrass, apply only to virus tolerant hybrids. Do not use on sweet corn. MOA=2 |
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Aim 2 EC Aim 1.9 EW |
0.5-1.0 fl oz
|
0.008-0.016 lb
|
Apply broadcast to corn from emergence until V8 growth stage. Excellent control of small sicklepod, glyphosate-resistant Palmer amaranth, and morningglory. Add a COC (1-2 gal/100 gals), NIS (1 qt/100 gals), or methylated seed oil (1-2 gal/100 gals). May be tank mixed with glyphosate for broader spectrum control in Roundup Ready corn. MOA=14 |
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Aatrex 4 WDL |
2.0 qt |
2.0 lb |
If ATRAZINE was not applied prior to corn emergence, apply a maximum of 2 lbs a.i./A. If a postemergence treatment is required following an earlier herbicide application, the total atrazine applied may not exceed 2.5 lbs a.i./A/calendar year. Applications to corn must be made before corn exceeds 12 “ tall. Always add crop oil concentrate at 1 gal per 100 gal of spray mix. MOA=5 |
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Banvel 4 S or Clarity 4L |
0.5-1.0 pt |
0.25-0.5 lb |
Apply at the 1 pt rate overtop corn up to 8" tall to give early control of vines and broadleaf weeds. The 0.5 pt rate may be applied overtop corn up to 36" tall. Do not apply under conditions which favor drift onto nearby crops. MOA=4 |
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Basagran 4 S |
1.5-2.0 pt |
0.75-1.0 lb |
Controls Palmer amaranth, cocklebur, bristly starbur, annual morningglory, and prickly sida. Treat when broadleaf weeds are small and actively growing. Adjust rate according to weed size as noted on label. Add crop oil concentrate at 1 qt/A. MOA=6 |
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1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Postemergence (POST) Herbicides for Weed Management in Corn (cont). |
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Rate/Acre Broadcast |
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Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Beacon 75 DF |
0.76 oz |
0.036 lb |
Apply overtop, directed or semi-directed to control rhizome johnsongrass 8 to 16" tall. BEACON may be applied overtop corn up to 20" tall. Directed or semi-directed applications may improve weed coverage and minimize crop injury. Add nonionic surfactant (1 qt/100 gal of spray mix), or crop oil concentrate (1 to 4 pt/A.). Do not apply BEACON to corn previously treated with COUNTER 15G, or COUNTER 20 CR (in-furrow) unless hybrid is IR (imidazolinone resistant). Injury may occur where BEACON is applied to corn previously treated with soil-applied LORSBAN or COUNTER 20CR T-banded. MOA=2 |
Buctril 4 EC + |
0.5-0.75 pt
+ |
0.25-0.38 lb
+ |
Apply overtop corn from 3- to 8-leaf stage (V3-V8) to control cocklebur, glyphosate- and ALS-resistant and Palmer amaranth. Apply when weeds are in the 2- to 4-leaf stage (V2-V4) or less than 6" tall. Less danger of volatility drift than 2,4-D or BANVEL. MOA=6 |
Callisto 4 SC + |
3.0 oz
+ |
0.094 lb
+ |
Good control of cocklebur, glyphosate- and ALS-resistant and Palmer amaranth, and several other weeds. Apply before Palmer amaranth reaches 5” tall. Apply overtop corn up to 12” tall. (Note: Without ATRAZINE, CALLISTO may be applied to corn up to 30” tall). Always add crop oil concentrate at 1 gal/100 gal of spray mix and UAN at a rate of 2.5% v/v or AMS at a rate of 8.5 lbs/100 gal. Do not apply postemergence if corn has been previously treated with COUNTER or LORSBAN insecticides. MOA=27+5 |
Distinct 70 DG (dicamba |
4.0-6.0 oz |
0.138-0.207 lb |
Apply overtop to corn between 4" and 24" tall. For corn 4 to 10" tall, use 6 oz/A. For corn 10 to 24" tall, use 4 oz/A. Use drop nozzles at the 4 oz/A rate as a rescue treatment for corn 24-36” tall. Always add nonionic surfactant at 1 qt/100 gal of spray mix. Do not use crop oil. Distinct provides excellent control of several broadleaf weeds, including cocklebur, sicklepod, annual morningglory, and glyphosate- and ALS-resistant Palmer amaranth. Do not apply under conditions which favor drift onto nearby, sensitive crops. Do not tank-mix with growth regulator herbicides, such as BANVEL or 2,4-D. MOA=4+19 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Postemergence (POST) Herbicides for Weed Management in Corn (cont). |
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Rate/Acre Broadcast |
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Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Expert 4.88 L |
2.5-3.75 qt |
0.47-0.71 lb ae |
USE ONLY ON ROUNDUP READY CORN HYBRIDS! EXPERT is a RESTRICTED USE PESTICIDE. Apply from emergence up till 12“tall corn. MOA=9+15+5 |
Glyphosate (various) 3 lb ae/gal
|
32 oz |
0.75 lb ae |
USE ONLY ON ROUNDUP READY CORN HYBRIDS! Apply broadcast in corn up to the V8 growth stage (30” tall). Use drop nozzles for 30-48” tall corn to avoid the whirls of the plants. Allow a minimum of 10 days between applications. May be tank mixed with ATRAZINE (application restricted to 12" tall corn) for residual control. MOA=9 |
Halex GT 4.389 L |
3.6-4.0 pt |
0.95-1.05 lb |
USE ONLY ON ROUNDUP READY CORN HYBRIDS! Apply broadcast in corn up to the V8 growth stage (30” height). Controls glyphosate- and ALS-resistant Palmer amaranth. Add a non-ionic surfactant (1-2 qt/100 gal) and AMS (8.5 lb/100 gal) to the spray tank. If activating rain (0.25”) is not received within 7-10 days, residual activity will be reduced. Do apply foliar carbamate or organophosphate insecticides 7 days before or 7 days after a HALEX GT application. Do not apply HALEX GT postemergence to fields previously treated with soil-applied COUNTER or LORSBAN insecticides. Do not apply HALEX GT in a nitrogen fertilizer carrier solution (i.e., UAN). Do not apply more than 4.0 pt/A/year of HALEX GT. MOA=15+9+27 |
Ignite 280 2.34 S
Liberty 1.67 S
|
22 oz
28-34 oz |
0.40 lb
0.37-0.44 lb |
USE ONLY ON CORN DESIGNATED AS LIBERTYLINK HYBRIDS! Apply LIBERTY overtop on corn from emergence up to the 24” tall corn (V7) (IGNITE limited to V5). Use drop nozzles when applying LIBERTY from 24-36” tall corn. Consult label for individual weed size recommendations. Controls glyphosate- and ALS-resistant Palmer amaranth (less than 3”). Will suppress rhizome johnsongrass. Always add AMS at 3 lb/A when applying IGNITE or LIBERTY. Do not add surfactant or crop oil. Do not exceed 44 oz (IGNITE) or 62 oz (LIBERTY) per acre per season. MOA=10 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Postemergence (POST) Herbicides for Weed Management in Corn (cont). |
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|
Rate/Acre Broadcast |
|
|
Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Impact 2.8 SC + |
0.75 oz
+ |
0.016 lb
+ |
Good to excellent control of cocklebur, glyphosate- and ALS-resistant and Palmer amaranth, and several other weeds. Apply before Palmer amaranth reaches 6” tall. Apply overtop corn up to 12” tall. Add MSO at 1.0-1.5 gal/100 gal of spray mix combined with a fertilizer solution of UAN at 1.25-2.5 gal/100 gal of spray mix or spray grade AMS at 8.5-17 lb / 100 gal. MOA=28 |
Laudis 3.5 SC + |
3.0 oz
+ |
0.082 lb
+ |
Apply overtop on corn from emergence up to the 8th collar stage (V8). Controls glyphosate- and ALS-resistant Palmer amaranth, sicklepod, Texas panicum, and prickly sida. Add 0.5 lb/A ATRAZINE to enhance control of weeds larger than 6 “(Restricts application to corn 12” tall or less). Add MSO at 1 gal/100 gal of spray mix plus 1.5 qt/A of UAN or 1.5 lb/A of spray grade AMS. Do not use NIS as weed control performance will be erratic. A second sequential 3 oz/A application can be made (wait a minimum of 14 days). Do not exceed 6 oz/A in a growing season. MOA=27 |
Lightning 70 DG (imazethapyr
|
1.28 oz |
0.042 lb |
USE ONLY ON CLEARFIELD CORN HYBRIDS! Apply overtop from the spiking stage up to 20" tall corn. Does not provide residual control of cocklebur and other large seeded broadleaf weeds. Always add crop oil concentrate (1 gal/100 gal) or nonionic surfactant (1 qt/100gal) of spray mix. Do not make more than one application of LIGHTNING per season. Do not use Counter 15G insecticide when Lightning will be applied to IT hybrids. Counter 20 CR (banded) may be used. LIGHTNING can be tank mixed with ATRAZINE or DISTINCT to broaden weed control. When tank mixing LIGHTNING with DISTINCT, do not use crop oil concentrate. MOA=2+2 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Postemergence (POST) Herbicides for Weed Management in Corn (cont).
|
Rate/Acre Broadcast |
|
|
Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Marksman 3.2 S (dicamba |
2.0-3.5 pt |
0.28-0.48 lb |
MARKSMAN is a RESTRICTED USE PESTICIDE. Apply for broadleaf weed control including annual morningglory and glyphosate- and ALS-resistant Palmer amaranth. A maximum of 3.5 pt/A may be applied during the period from corn emergence through the 5 leaf stage (V5) or 8” tall. Reduce rate to 2 pt/A on coarse textured soils. Non-ionic surfactant may be added. Do not add crop oil. MOA=4+5 |
Option 35 DF |
1.5-1.75 oz |
0.003-0.038 lb |
Apply to corn at the V1 to V6 growth stage. Use directed or drop nozzles for applications at the V7-V8 growth stage. Add methylated or ethylated seed oil (1.5 pt/A) in combination with nitrogen fertilizer (1.5-2 qt/A of UAN or 1.5-3 lb/A of AMS). Do not use OPTION in the same season as COUNTER 15G, COUNTER 20CR, DYFONATE and THIMET. Note: In fields heavily infested with johnsongrass, apply only to virus tolerant hybrids. MOA=2 |
Permit 75 DF |
0.67-1.33 oz |
0.031-0.062 lb |
Apply overtop to control cocklebur, common ragweed, velvetleaf and yellow nutsedge. Weak on sicklepod and morningglory. Add surfactant (1-2 qt/100 gal) or crop oil (1 gal/100 gal). May be tank-mixed with Accent or Beacon for johnsongrass control. MOA=2 |
Prowl H2O 3.8 CS Prowl 3.3 EC + |
2.0-3.0 pt
1.8-2.4 pt + |
0.95-1.43 lb
0.75-1.0 lb + |
Apply over-the-top after corn emergence up to 12” tall (V4) but when seedling grasses are less than 1” tall. Use the higher rates on fine-textured soils. In case of stand failure, corn seed should be replanted below the herbicide treated zone. MOA=3 |
Pursuit 70 DG Pursuit 2 AS |
1.44 oz
4.0 oz |
0.063 lb |
USE ONLY ON CLEARFIELD CORN HYBRIDS! Use only on imidazolinone-resistant corn hydrids. Apply overtop to actively growing weeds (less than 3”). Always add crop oil concentrate (1.25 gal/100 gal), MSO (1 gal/100 gal), or NIS (1 qt/100gal) plus a nitrogen fertilizer solution [UAN or similar] (1.25-2.5 gal/100 gal) or AMS 12-15 lb/100 gal). Do not make more than one application of PURSUIT per season. Consult label on use of soil applied insecticides and other precautions. Wait a minimum of 45 days between application and harvest. MOA=2 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Postemergence (POST) Herbicides for Weed Management in Corn (cont). |
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|
Rate/Acre Broadcast |
|
|
Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Resolve 25 DF |
1.0 oz |
0.016 lb |
Apply overtop to corn from emergence up to 12 inch corn (6 collars visible), whichever is more restrictive, to control annual morningglory and cocklebur. Weak on Palmer amaranth. Add surfactant (1 qt/100 gal) plus ammonium nitrogen fertilizer (2 qt/A) or ammonium sulfate (2 lb/A). Soil moisture is needed for activation, if rainfall is not received within 7 days of application, follow-up with cultivation or a sequential application of ACCENT. Do not apply more than 2.0 oz/A of RESOLVE 25 DF in a growing season. Do not tank mix RESOLVE 25 DF with BASAGRAN or LADDOCK or severe crop injury may occur. Do not tank mix RESOLVE 25 DF with a foliar applied organophosphate insecticides, such as LORSBAN, MALATHION, PARATHION, etc., as severe crop injury may occur. MOA=2 |
Resolve Q (mp) (thifensulfuron |
1.25 oz |
0.014 lb |
Apply overtop to corn from emergence up to 20 inch corn (7 collars visible), whichever is more restrictive, to control annual morningglory and cocklebur. Provides only suppression of Palmer amaranth. Add surfactant (1 qt/100 gal) plus ammonium nitrogen fertilizer (2 qt/A) or ammonium sulfate (2 lb/A). Soil moisture is needed for activation, if rainfall is not received within 7 days of application, follow-up with cultivation or a sequential application of ACCENT. Do not apply more than 2.5 oz/A of RESOLVE Q in a growing season. Do not tank mix RESOLVE Q with BASAGRAN or LADDOCK or severe crop injury may occur. Do not tank mix RESOLVE Q with a foliar applied organophosphate insecticides, such as LORSBAN, MALATHION, PARATHION, etc., as severe crop injury may occur. MOA=2 |
Sequence 5.25 S (glyphosate |
2-2.5 pt |
0.56-0.71 lb ae |
USE ONLY ON ROUNDUP READY CORN HYBRIDS! Apply from emergence up till corn plants reach 30 “ tall. Do not exceed 2.5 pt/A in a single application or 5.0 pt/A total per year. Can be tank mixed with ATRAZINE for improved residual broadleaf weed control (consult label for additional tank mix choices). MOA=9+15 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Postemergence (POST) Herbicides for Weed Management in Corn (cont). |
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|
Rate/Acre Broadcast |
|
|
Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Steadfast 75DF (nicosulfuron |
0.75 oz |
0.023 lb |
Apply to corn up to 20” tall or 6 collars (V6). Always add COC (1 gal/100 gallons) or NIS (1 qt per 100 gallons). The label recommends the addition of nitrogen fertilizer solution (2 qt/A) or ammonium sulfate (4lb/A). Do not apply to corn previously treated with COUNTER 15G, or COUNTER 20CR (in-furrow). Injury may occur when STEADFAST is applied to corn previously treated with soil applied LORSBAN, THIMET, or COUNTER 20CR T-banded. Do not tank mix STEADFAST with BASAGRAN or LADDOCK or severe crop injury may occur. Do not tank mix STEADFAST with a foliar applied organophosphate insecticides, such as LORSBAN, MALATHION, PARATHION, etc., as severe crop injury may occur. MOA=2+2 |
Steadfast ATZ (nicosulfuron |
14 oz |
0.024 lb |
Apply to corn up to 12” tall (V4). Add nonionic surfactant at 1 qt/100 gal or crop oil concentrate at 1 gal/100 gal of spray mix plus 2 qt/A of urea ammonium nitrate or 2 lb/A of ammonium sulfate. Do not apply STEADFAST ATZ to corn previously treated with a soil insecticide such as COUNTER 15G, COUNTER 20CR (in-furrow), THIMET, LORSBAN, or COUNTER 20CR (T-banded). Do not tank mix STEADFAST ATZ with BASAGRAN or LADDOCK or severe crop injury may occur. Do not tank mix STEADFAST ATZ with a foliar applied organophosphate insecticides, such as LORSBAN, MALATHION, PARATHION, etc., as severe crop injury may occur. MOA=2+2+5 |
Stout 72.5 DF (nicosulfuron |
0.5-0.75 oz |
0.021-0.025 lb |
Provides selective postemergence control of grass and broadleaf weeds in field corn. Apply to corn up to 16“ tall (V5). Do not apply to field corn grown for seed, popcorn, or sweet corn. Add NIS at 1 qt/100 gal, or COC at 1 gal/100 gal of spray mix. Do not apply STOUT to corn previously treated with COUNTER 15G, or COUNTER 20CR (in-furrow) unless hybrid is IR (imidazolinone resistant). MOA=2+2 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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Postemergence (POST) Herbicides for Weed Management in Corn (cont). |
|||
|
Rate/Acre Broadcast |
|
|
Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
Status 56WDG (dicamba |
5-10 oz
|
0.223-0.446 lb |
Apply overtop on corn from V2 (4“ tall) to V10 (36“ tall) growth stages. Controls many broadleaf weeds including morningglory, sicklepod, and glyphosate- and ALS-resistant Palmer amaranth. Consult label for a list of tank mix partners and other restrictions. MOA=4+19 |
2,4-D 4S |
0.5-1.0 pt |
0.25-0.5 lb |
Apply overtop for corn under 8" tall. Controls many broadleaf weeds including morningglory, sicklepod, and glyphosate- and ALS-resistant Palmer amaranth. On taller corn, use directed application to prevent crop injury and provide better spray coverage of weeds. Do not apply under conditions which favor drift onto nearby, sensitive crops. MOA=4 |
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems. |
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POST Directed Herbicides for Weed Management in Corn |
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|
Rate/Acre Broadcast |
|
|
Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
2,4-D 4S |
0.5-1.0 pt |
0.125-0.25 lb |
Apply only as a directed spray from 8 “ tall up to tasseling using drop nozzles to minimize contact with corn plant. Controls morningglory and other broadleaf plants. If corn plants are growing rapidly reduce 2.4-D rate to 0.5 pt to minimize crop injury potential. MOA=4 |
Aim 2EC Aim 1.9EW |
0.5-2.0 fl oz
|
0.008-0.031 lb
|
Apply only as directed spray from V8 to V14 growth stage. Controls annual morningglory and pigweed. Add a COC (1-2 gal/100 gals), NIS (1 qt/100 gals), or MSO (1-2 gal/100 gals). Avoid directing the spray in the whorl of the plant. MOA=14 |
Evik 80WDG |
1.25-2.5 lb |
1.0-2.0 lb |
Apply only as a directed spray. Minimum corn height: AMETRYN (MOA=5) -12 in., LINURON (MOA=7) -15 in., PARAQUAT (MOA=22) -10 in. Spray to cover weeds no more than 3 to 4 in. tall. Where rate range is given, use lower rate when weeds are no taller than 2 in. and higher rate for weeds up to 4 in. tall. Use a nonionic surfactant to improve spray coverage of weeds. Do not apply AMETRYN within 3 weeks of tasseling. Do not apply PARAQUAT higher than 3” on the stalk. |
Gramoxone Inteon 2E |
1.0-2.0 pt |
0.25-0.5 lb |
|
Linex 4L Lorox 50DF |
1.25-3.0 pts.
1.25-3.0 lb |
0.63-1.5 lb
0.63-1.5 lb |
|
1Mode of Action (MOA) identifies the site of action(s) of that particular product. This aids in rotating herbicide products to avoid resistance problems.
Harvest Aids in Corn
|
Rate/Acre Broadcast |
|
|
Herbicide |
Formulation |
Active Ingredient |
Remarks/Precautions1 |
2,4-D 4S |
1.0-2.0 pt |
0. 25-0.5 lb |
Apply broadcast after the hard dough or dent growth stage to control vines (i.e., annual morningglory) that may interfere with harvest. Do not graze or harvest for fodder until 7 days after application. MOA=4 |
Aim 2EC Aim 1.9EW |
1.0-2.0 oz
|
0.008-0.031 lb
|
Apply after physiological maturity (black layer has formed). Desiccates annual morningglory and other harvest impediments. Add a COC (1-2 gal/100 gals), NIS (1 qt/100 gals), or MSO (1-2 gal/100 gals) to the spray mix. MOA=14 |
Glyphosate |
96 oz |
3.0 lb ae |
Apply after physiological maturity (less than 35% moisture, black layer has formed). Allow 7 days between application and harvest. Not recommended for corn grown for seed. MOA=9 |
The Label is the law. Always read and follow all pesticide label restrictions.
For more information download the South Carolina Corn Production Guide