Slide Presentation

TITLE    (click title to view slides)
Field Corn Weed Control - 2018

AUTHOR
Eric P. Prostko
Professor and Extension Weed Specialist
University of Georgia

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• PowerPoint - 23.5 MB
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TABLE OF CONTENTS
  1. 2018 Field Corn Weed Management Update
  2. Field Corn Weed Control - General
  3. Herbicide Carryover in GA?
  4. Herbicide Carryover or Nematodes
  5. Field Corn Yield Loss (%) Caused by Uncontrolled Weeds in Georgia Weed Science Research Trials (2007-2017). Treated vs. Non-treated
  6. Later POST Applications?
  7. Marestail in Field Corn (i.e. Horseweed)
  8. Ryegrass Control
  9. Field Corn Weed Control - 2017
  10. Late-Season Weed Control
  11. Field Corn Weed Control - 2017
  12. Field Corn Weed Control - 2017
  13. Normal Halex GT Injury
  14. Field Corn Weed Control - 2017
  15. Field Corn Weed Control - 2017
  16. Morningglory Control in Field Corn
  17. Morningglory Control in Corn
  18. Do we need to rethink laybys????
  19. Evik or Not?
  20. What herbicides can you use in field corn if you have resistance to glyphosate, atrazine, and/or ALS herbicides?
  21. Field Corn Weed Control Without Atrazine or Glyphosate - 2017
  22. New (er) Stuff
  23. Enlist(TM) Herbicide Tolerant Corn
  24. Enlist(TM) Field Corn Hybrids - 2018
  25. Post-Harvest
  26. Post-Harvest Control of Palmer Amaranth (8.1" average: 2"-17" range at application)
  27. Post-Harvest Control of Tropical Spiderwort
  28. Questions/Comments?



SLIDE CONTENTS
  1. Eric P. Prostko Professor/Extension Weed Specialist Dept. Crop & Soil Sciences 2018 Field Corn Weed Management Update
  2. Field Corn Weed Control - General Other mgt. practices are important! Tillage Plant population Row spacing Nematode, insect, disease control Irrigation A healthy and uniformly spaced crop is better able to compete with weeds
  3. Herbicide Carryover in GA? Never say never but …… low OM high sand content warm temperatures ample rainfall/irrigation
  4. Herbicide Carryover or Nematodes Burke County April 2017 Stubby Root Nematodes 21/100cm3 of soil >9 is threshold
  5. Figure 1. Field Corn Yield Loss (%) Caused by Uncontrolled Weeds in Georgia Weed Science Research Trials (2007-2017). Treated vs. Non-treated 200 Bu/A X 0.36 X $3.50 = $252/A 200 Bu/A X 0.16 X $3.50 = $112/A
  6. Later POST Applications? V6 stage all leaves are initiated Ear shoot initiation Kernel rows/ear begins Tassel initiation Growing point above soil surface ~500 GDD
  7. Marestail in Field Corn (i.e. Horseweed) Tillage Burndown Liberty (glufosinate) + atrazine? Glyphosate + Dicamba or 2,4-D? Sharpen + MSO 0 day plant-back Paraquat + atrazine Residual atrazine In-Crop Liberty (LL) Dicamba 2,4-D Enlist corn - 2,4-D choline
  8. Ryegrass Control Glyphosate-resistant or not? Fall (mid-October – Mid-November) Tillage (double disk) or Dual Magnum @ 1.33 pt/A Mid-January – Mid-February 2” - 6” tall Select Max 0.97EC @ 6 oz/A or Clethodim 2EC @ 6-8 oz/A Corn – 30 DBP Nighttime temps > 470 F March 1-20 Gramoxone 2SL @ 3-4 pt/A May need 2 applications (10-14 days apart) + atrazine @ 1 qt/A Source: Dr. Jason Bond, MS State University
  9. Field Corn Weed Control - 2017 CN-02-17 April 27 13 DAT NTC Roundup P-Max @ 32 oz/A Atrazine @ 64 oz/A Prowl H2O @ 32 oz/A
  10. Late-Season Weed Control CN-02-17 July 24 118 DAP NTC Roundup P-Max @ 32 oz/A Atrazine 4L @ 64 oz/A Prowl H20 @ 32 oz/A Applied 17 DAP
  11. Field Corn Weed Control - 2017 CN-02-17 April 27 13 DAT NTC Liberty @ 29 oz/A Atrazine @ 64 oz/A Prowl H20 @ 32 oz/A
  12. Field Corn Weed Control - 2017 CN-02-17 April 27 13 DAT NTC Halex GT @ 58 oz/A Atrazine @ 64 oz/A Adept @ 0.25% v/v
  13. Normal Halex GT Injury CN-05-17 April 24 7 DAT
  14. Field Corn Weed Control - 2017 CN-02-17 April 27 13 DAT NTC Revulin Q @ 3.4 oz/A Atrazine @ 64 oz/A Adept @ 0.25% v/v
  15. Field Corn Weed Control - 2017 CN-02-17 April 27 13 DAT NTC Laudis @ 3 oz/A Atrazine @ 64 oz/A MES 100 @ 1% v/v
  16. Morningglory Control in Field Corn
  17. Morningglory Control in Corn as much atrazine as possible 1.0 lb/A – PRE fb 1.5 lb/A – POST small grain rotations 2,4-D, Clarity, Status, Aim, ET, Evik (PDIR) Enlist Corn??? Liberty-Link® Corn Systems split applications of glyphosate (RR corn) * 1st application + atrazine Harvest Aids Aim Early-harvest
  18. Do we need to rethink laybys???? CN-06-15 July 29 133 DAP NTC Atrazine 4L @ 32 oz/A (PRE) Roundup WM @ 32 oz/A + Atrazine @ 48 oz/A (21 DAP) Atrazine 4L @ 32 oz/A (PRE) Roundup WM @ 32 oz/A + Atrazine @ 48 oz/A (21 DAP) Evik @ 2 lb/A + NIS (37 DAP)
  19. Evik or Not? CN-01-16 July 7 108 DAP NTC Atrazine 4L @ 32 oz/A (PRE) Roundup P-Max 5.5SL @ 32 oz/A (POST) Atrazine 4L @ 48 oz/A (POST) Atrazine 4L @ 32 oz/A (PRE) Roundup P-Max 5.5SL @ 32 oz/A (POST) Atrazine 4L @ 48 oz/A (POST) Evik 80DG @ 2 lbs/A (PDIR) NIS @ 0.25% v/v (PDIR)
  20. What herbicides can you use in field corn if you have resistance to glyphosate, atrazine, and/or ALS herbicides? Residuals Zidua Dual Magnum Warrant Prowl Postemergence* Liberty Status Revulin Q Impact/Armezon Laudis Capreno Halex GT 2,4-D * double-crop soybean rotations?
  21. Field Corn Weed Control Without Atrazine or Glyphosate - 2017 NTC (209 Bu/A) CN-03-17 May 18 51 DAP DKC 66-59 Dual II Magnum @ 16 oz/A (PRE) Laudis @ 3 oz/A (28 DAP) COC @ 1% v/v (28 DAP) AMS Xtra @ 2.5% v/v (28 DAP) (251 Bu/A) Warrant @ 48 oz/A (PRE) Laudis @ 3 oz/A (28 DAP) COC @ 1% v/v (28 DAP) AMS Xtra @ 2.5% v/v (28 DAP) (247 Bu/A)
  22. New (er) Stuff
  23. Enlist™ Herbicide Tolerant Corn tolerance to 2,4-D and Assure + GLY Trait was deregulated in September 2014 and herbicide in October 2014. U.S. launch in 2018 (SE??). Colex-D™ technology 2,4-D choline lower volatility lower drift potential enhanced handling/mixing characteristics reduced odor 1 PRE application + 2 POST applications (30” or V8 stage) Enlist™ Duo DMA-Glyphosate (1.71 lb ae/gal) + 2,4-D choline (1.63 lb ae/gal) Enlist™ One 2,4-D choline (3.8 lb ae/gal) 2,4-D choline
  24. Enlist™ Field Corn Hybrids - 2018 China approval June 2017 Limited or no data for SE????? Broadbeck Dairyland Mycogen Pfister Prairie Brand
  25. Post-Harvest Palmer amaranth tropical spiderwort Benghal dayflower
  26. Post-Harvest Control of Palmer Amaranth (8.1” average: 2”-17” range at application) CN-01B-11 September 15 30 DAT NTC Gramoxone Inteon 2SL @ 3 pt/A 2,4-D Amine 3.8SL @ 1 pt/A Primary @ 1% v/v Gramoxone Inteon 2SL @ 3 pt/A Clarity 4SL @ 8 oz/A Primary @ 1% v/v
  27. Post-Harvest Control of Tropical Spiderwort Untreated Gramoxone POST1 + POST2 POST1: 8-10” tall COMBE POST2: 2 weeks later Photo 1 week after POST2
  28. Questions/Comments?