Slide Presentation

TITLE    (click title to view slides)
Field Corn Weed Control Update 2026

AUTHOR
Eric P. Prostko
Extension Weed Specialist
Dept. Crop & Soil Sciences
University of Georgia

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TABLE OF CONTENTS
  1. Field Corn Weed Control Update 2026
  2. Where is grain agronomist?
  3. Topics for Discussion
  4. Beware of Google/AI Recommendations!
  5. Field Corn Yield Loss (%) Caused by Uncontrolled Weeds in UGA Weed Science Irrigated Research Trials (2007-2025)
  6. Ryegrass in Field Corn - 2025
  7. Ryegrass in Corn
  8. Annual Ryegrass Control (10-25 days after early flower application) with Roundup WeatherMax 5.5SL (Averaged over 6 locations)
  9. Brand Name Halex GT vs Home-Made Halex GT
  10. Home-Made Halex GT - 2025
  11. Field Corn Weed Control - 2025 - Halex GT (Applied 16 DAP, V3-4, P2042VYHR)
  12. Field Corn Weed Control - 2025
  13. Enlist™ Herbicide Tolerant Corn
  14. Enlist™ Herbicide Tolerant Corn Programs
  15. Enlist™ Field Corn Weed Control - 2025
  16. Enlist™ Field Corn Weed Control - 2025
  17. Enlist™ Field Corn Weed Control - 2025
  18. Enlist™ Field Corn Weed Control - 2025
  19. Enlist™ Field Corn Hybrids for Georgia - 2025
  20. Enlist One/ESA/Runoff Mitigation (4-6 credits)
  21. Volunteer Corn/Replant?
  22. Field Corn Control with Select Max 0.97EC @ 6 oz/A + Induce @ 0.25% v/v
  23. Field Corn Control with Gramoxone 3SL @ 32 oz/A + Tricor 4F @ 4 oz/A + Induce @ 0.25% v/v
  24. Boron?
  25. Roundup + Atrazine + Zidua + Boron - 2025
  26. Roundup PowerMax3 5.88SL @ 27 oz/A + Aatrex 4L @ 64 oz/A + Zidua 4.17SC @ 2.5 oz/A ± 10% Liquid Boron @ 32 oz/A or 64 oz/A
  27. Surtain Herbicide
  28. Surtain (saflufenacil + pyroxasulfone) Encapsulation
  29. Field Corn Weed Control - 2025
  30. Cocklebur in Field Corn
  31. Peanut Control? Peanuts: V4-5; 2-3" tall;4-5" wide
  32. BD/TSW Control in Field Corn
  33. Benghal Dayflower/Tropical Spiderwort - HPPD’s
  34. BD/TS Control in Field Corn
  35. Post-Harvest Tropical Spiderwort Control - 2024
  36. Post-Harvest
  37. Post-Harvest Weed Control - 2021
  38. Special Problems
  39. Imazapyr/Triclopyr Contamination - Drone Application
  40. Name Recognition? Counter INFR
  41. Reflex (fomesafen) Carryover on Field Corn
  42. Field Corn/Potash - 2025 - Integra 6410
  43. Pigweed Symptoms
  44. Pigweed Tissue Tests
  45. Questions/Comments?



SLIDE CONTENTS
  1. Field Corn Weed Control Update 2026 Eric P. Prostko Extension Weed Specialist Dept. Crop & Soil Sciences
  2. Where is grain agronomist? 04/17/25 – 5:17 AM
  3. Topics for Discussion AI Recommendations Weed Control Costs Ryegrass Halex GT vs Home-Made Enlist Corn V. Corn Control/Replant Boron??? Cocklebur V. peanut Post-Harvest Problems
  4. Beware of Google/AI Recommendations!
  5. Field Corn Yield Loss (%) Caused by Uncontrolled Weeds in UGA Weed Science Irrigated Research Trials (2007-2025) Treated vs. Non-treated 200 Bu/A X 0.32 X $4.14 = $265/A 250 Bu/A X 0.32 X $4.14 = $331/A 300 Bu/A X 0.32 X $4.14 = $397/A What about harvest? What about next year?
  6. Ryegrass in Field Corn - 2025 Glyphosate resistant??? Assume it is? Gramoxone – preplant 2 apps Accent Q or Steadfast Q Counter (INFR)? Hybrid Tolerance? Liberty Need warm temps Enlist Corn? Assure II (quizalofop) Hoelon (diclofop resistant population?) G. Harris 04/21/25 Turner Co.
  7. Ryegrass in Corn – 2025 Treated with Liberty @ 43 oz/A + AMS @ 2 lbs/A + Atrazine @ 32 oz/A + Zidua @ 2 oz/A C. Traugh Seminole Co. April 17, 2025 7 DAT no burndown wet weather wind
  8. Annual Ryegrass Control (10-25 days after early flower application) with Roundup WeatherMax 5.5SL (Averaged over 6 locations) Adapted from:Lins et al. 2007. Weed Technology 21:602-605
  9. Brand Name Halex GT vs Home-Made Halex GT Brand Name Halex GT 4.389SC $42/gal @ 58 oz/A = $19.03/A 0.947 lbs ai/A s-metolachlor + 0.947 lbs ae/A glyphosate (K-salt) + 0.0947 bs ai/A mesotrione Home-Made Halex GT Incinerate 4SC (mesotrione) = $165/gal @ 3 oz/A = $3.87/A CornerStone 5 Plus 5.5SL (glyphosate-IPA, 4 lb ae/gal) = $15/gal @ 30.3 oz/A = $3.55/A Charger Basic 7.62EC (s-metolachlor) = $40/gal @ 16 oz/A = $5.00/A $19.03/A vs. $12.42/A ($6.61/A savings) But mesotrione labels say……….
  10. Home-Made Halex GT - 2025 J. Cook/M. Grizzle May 9, 2025 Roundup Dual Magnum Generic Callisto Is this potential injury worth $6.61/A?? Who will pay for new innovations/discovery?
  11. Field Corn Weed Control – 2025 Halex GT (Applied 16 DAP, V3-4, P2042VYHR) CN-07-25 May 7 34 DAP NTC Halex GT 4.389SC @ 58 oz/A Aatrex 4L @ 64 oz/A Induce @ 0.25% v/v RUPM3 5.88SL @ 25.3 oz/A Callisto 4SC @ 3 oz/A Dual Magnum 7.62EC @ 16 oz/A Aatrex 4L @ 64 oz/A Induce @ 0.25% v/v
  12. Field Corn Weed Control - 2025 CN-07-25 August 19 138 DAP NTC Halex GT 4.389SC @ 58 oz/A Aatrex 4L @ 64 oz/A Induce @ 0.25% v/v Applied 16 DAP
  13. Enlist™ Herbicide Tolerant Corn tolerance to 2,4-D, quizalofop, glyphosate, glufosinate Trait – 2014 Enlist Duo® - 2014 Enlist One® - 2017 Colex-D™ technology 2,4-D choline lower volatility (than ester) enhanced handling/mixing characteristics reduced odor 1 PRE application + 2 POST applications (30” or V8 stage, 12 days apart) Enlist Duo® DMA-Glyphosate (1.71 lb ae/gal) + 2,4-D choline (1.63 lb ae/gal) 3.5 pt/A Enlist One® 2,4-D choline (3.8 lb ae/gal) 1.5-2.0 pts/A 2,4-D choline
  14. Enlist™ Herbicide Tolerant Corn Programs Program #1 1) Atrazine – PRE followed by 2) Liberty + Enlist One + One of the following (Anthem Maxx, Dual Magnum, Enversa, Outlook, Prowl, Warrant, Zidua) - POST Program #2 1) One of the following PRE (Dual Magnum, Enversa, Outlook, Warrant) followed by 2) Liberty + Enlist One + Atrazine - POST 2,4-D choline
  15. Enlist Field Corn Weed Control - 2025 CN-04-25 May 8 29 DAT NTC Liberty Ultra 1.76SL@ 24 oz/A Enlist One 3.8SL @ 32 oz/A Aatrex 4L @ 32 oz/A Applied 14 DAP (V3-V4)
  16. Enlist™ Field Corn Weed Control - 2025 CN-04-25 May 8 29 DAT NTC Liberty Ultra 1.76SL @ 24 oz/A Enlist One 3.8SL @ 32 oz/A Dual Magnum 7.62EC @ 16 oz/A Applied 14 DAP (V3-V4) Liberty Ultra 1.76SL @ 24 oz/A Enlist One 3.8SL @ 32 oz/A Outlook 6EC @ 12.8 oz/A Applied 14 DAP (V3-V4)
  17. Enlist Field Corn Weed Control - 2025 CN-04-25 May 8 29 DAT NTC Liberty Ultra 1.76SL@ 24 oz/A Enlist One 3.8SL @ 32 oz/A Prowl H2O 3.8SC @ 32 oz/A Applied 14 DAP (V3-V4)
  18. Enlist Field Corn Weed Control - 2025 CN-04-25 July 30 112 DAT NTC Liberty Ultra 1.76SL @ 24 oz/A Enlist One 3.8SL @ 32 oz/A Anthem Maxx 4.3SC @ 3 oz/A Applied 14 DAP (V3-V4)
  19. Enlist Field Corn Hybrids for Georgia – 2025 Averaged Over 22 Locations Source: K. Phillips, Pioneer
  20. Enlist One/ESA/Runoff Mitigation (4-6 credits)
  21. Volunteer Corn/Replant?
  22. Field Corn Control with Select Max 0.97EC @ 6 oz/A + Induce @ 0.25% v/v NTC Applied V3-V4 28 DAT Applied V5-V6 18 DAT CN-01-25 May 7 42 DAP
  23. Field Corn Control with Gramoxone 3SL @ 32 oz/A + Tricor 4F @ 4 oz/A + Induce @ 0.25% v/v NTC Applied V3-V4 17 DAT Applied V5-V6 7 DAT CN-01-25 April 26 31 DAP
  24. Boron?
  25. Roundup + Atrazine + Zidua + Boron - 2025 CN-08-25 May 7 28 DAT NTC Roundup PowerMax3 5.88SL @ 27 oz/A Aatrex 4L @ 64 oz/A Zidua 4.17SC @ 2.5 oz/A Roundup PowerMax3 5.88SL @ 27 oz/A Aatrex 4L @ 64 oz/A Zidua 4.17SC @ 2.5 oz/A 10% Liquid Boron @ 32 oz/A Roundup PowerMax3 5.88SL @ 27 oz/A Aatrex 4L @ 64 oz/A Zidua 4.17SC @ 2.5 oz/A 10% Liquid Boron @ 64 oz/A
  26. Roundup PowerMax3 5.88SL @ 27 oz/A + Aatrex 4L @ 64 oz/A + Zidua 4.17SC @ 2.5 oz/A ± 10% Liquid Boron @ 32 oz/A or 64 oz/A Yield (Bu/A) CN-08-25 Pioneer P13777PWUE Applied 14 DAP (V3-V4) P = 0.3167 CV = 8.42
  27. Surtain Herbicide Surtain 1.628SC saflufenacil (Sharpen) – 0.626 lbs/gal pyroxaslfone (Zidua) – 1.002 lbs/gal solid encapsulated herbicide technology 11 oz/A PRE-V3 residual control only Have not been a huge fan of pyroxasulfone applied PRE? injury
  28. Surtain (saflufenacil + pyroxasulfone) Encapsulation Surtain Source: BASF
  29. Field Corn Weed Control - 2025 CN-06-25 August 19 138 DAP NTC Roundup PowerMax3 5.88SL @ 30 oz/A Surtain 1.628SC @ 11 oz/A Aatrex 4L @ 32 oz/A Induce @ 0.25% v/v AMSOL @ 2.5% v/v Applied 14 DAP
  30. Cocklebur in Field Corn PRE: Acuron, Atrazine, Corvus, Resicore, Sharpen POST: Armezon, Atrazine, Basagran, Callisto, Capreno, Clarity, Enlist One, Halex GT, Impact, Laudis, Liberty, Revulin Q, Roundup, Sandea, Status *2 seeds/bur *now/later *can emerge from 6”
  31. Peanut Control? Peanuts: V4-5; 2-3” tall;4-5” wide PE-13-25 June 3 20 DAT NTC Liberty Ultra 1.76SL @ 24 oz/A Laudis 3.5SC @ 3 oz/A Aatrex 4L @ 64 oz/A Agridex @ 1% v/v AMSOL @ 2.5% v/v Roundup PowerMax3 5.5SL @ 30 oz/A Laudis 3.5SC @ 3 oz/A Aatrex 4L @ 64 oz/A AMSOL @ 2.5% v/v
  32. BD/TSW Control in Field Corn Residuals Dual Magnum, Outlook, Warrant, Zidua, Anthem Maxx POST 2,4-D (crop injury issues unless Enlist hybrid) Basagran Halex GT/Callisto Lay-By/Hood Aim Evik Gramoxone Post-Harvest Gramoxone, 2,4-D
  33. Benghal Dayflower/Tropical Spiderwort – HPPD’s TSW-01-22 August 17 22 DAT Callisto 4SC @ 3 oz/A Agridex @ 1% v/v
  34. BD/TS Control in Field Corn Untreated Gramoxone Max 3SC @ 16 oz/A Dual Magnum 7.62EC @ 1.33 pt/A Herbimax @ 1% v/v Lay-By CN-09-05 12 DAT
  35. Post-Harvest Tropical Spiderwort Control – 2024 COMBE: 12-16” tall; flowering; POST1 = 09/10/24; POST2= 09/17/24 PH-01A-24 October 2 15 DAT (POST2) NTC Gramoxone 3SL @ 32 oz/A Induce @ 0.25% v/v POST1 + POST2 Roundup P-MAX3 5.88 SL @ 32 oz/A Enlist One 3.8SL @ 24 oz/A POST1 + POST2
  36. Post-Harvest
  37. Post-Harvest Weed Control - 2021 Gramoxone 2L @ 3 pts/A + Tricor 4L @ 8 oz/A + NIS @ 0.25% v/v 09/24/21 Day of Application 10/22/21 28 Days After Treatment (strips left on purpose as checks)
  38. Special Problems
  39. Imazapyr/Triclopyr Contamination – Drone Application Triclopyr = 0.01 mg/kg Imazapyr = 3.8 µg/kg Jay, FL April/May 2025
  40. Name Recognition? Counter INFR
  41. Reflex (fomesafen) Carryover on Field Corn J. Bennett May 1, 2025
  42. Field Corn/Potash – 2025 Integra 6410 09/09/24 K Soil Test
  43. Pigweed Symptoms Source: S. McAllister
  44. Pigweed Tissue Tests Peanut Field (K = 2.1%) Corn Field (Bad) K = 0.61% Corn Field (Good) K = 2.03% Source: N. Chammoun
  45. Questions/Comments?