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TITLE    (click title to view slides)
Weed Control Update for Wheat - 2003

AUTHOR
Dr. A. Stanley Culpepper
University of Georgia

Dr. Alan C. York
North Carolina State University

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TABLE OF CONTENTS
  1. Weed Control Update for Wheat - 2003
  2. Italian Ryegrass Control with Hoelon
  3. Hoelon is still excellent material where resistance is not a problem
  4. Hoelon Rate for POST on Wheat
  5. Proper Timing of Hoelon POST
  6. Use of Adjuvants with Hoelon
  7. Hoelon POST on Wheat and Weather
  8. Hoelon POST on Wheat Carriers and Tank Mixes
  9. Alternatives to Hoelon for Ryegrass Control
  10. Alternatives to Control Hoelon-Resistant Ryegrass
  11. Alternatives to Control Hoelon-Resistant Ryegrass - Finesse
  12. Finesse 75 DF
  13. Mid-Atlantic University Trials: 1999 and 2000
  14. Late-season Italian ryegrass control by Finesse at 0.5 oz/acre applied preemergence
  15. Late-season Italian ryegrass control by Finesse at 0.4 oz/acre applied postemergence
  16. Finesse 75 DF - Rotational concerns
  17. Rotational Restrictions for Finesse
  18. Finesse carryover on non-STS beans
  19. Alternatives to Control Hoelon-Resistant Ryegrass - Axiom
  20. Georgia counties infested with diclofop-resistant Italian ryegrass
  21. Axiom herbicide
  22. Axiom
  23. Axiom
  24. Wheat Response to Axiom. Plains, GA, 2001
  25. Axiom herbicide - rates
  26. Axiom herbicide - Must be Activated and Timely
  27. Late-season Italian ryegrass control by Axiom applied at spike wheat. Plains and Tifton GA. 2001 and 2002
  28. Hoelon-susceptible Italian ryegrass control by Axiom and Hoelon
  29. Hoelon-susceptible Italian ryegrass control by Axiom and Hoelon in Virginia
  30. Hoelon-resistant Italian ryegrass by Axiom in NC
  31. Hoelon-resistant Italian ryegrass control by Axiom and Hoelon in South Carolina
  32. Alternatives to Control Hoelon-Resistant Ryegrass - Clearfield system, and Osprey
  33. Osprey
  34. Trial comparison
  35. Late-season ryegrass control by Osprey applied timely in NC field studies
  36. Broadleaf Weed Control Options
  37. 2,4-D
  38. Susceptibility of Small Grains to Phenoxy Herbicides As Affected by Growth Stage
  39. Wheat Response to 2,4-D. Macon County, 2000
  40. Express
  41. Express + MCPA
  42. Harmony Extra



SLIDE CONTENTS
  1. Weed Control Update for Wheat 2003 A. Stanley Culpepper and Alan C. York
  2. Italian Ryegrass Control with Hoelon
  3. Hoelon is still excellent material where resistance is not a problem
  4. Hoelon Rate for POST on Wheat Ryegrass pt/acre 1- to 3 leaf 1.33 3- to 4-leaf 1.33 to 2 5-leaf, 2 tillers 2 to 2.67
  5. Proper Timing of Hoelon POST Timeliness is critical !!! With normal planting date, generally best to apply before Christmas 1.5 pt before Christmas is better than 2.67 pt in February/March
  6. Use of Adjuvants with Hoelon POST on Wheat Can add COC May enhance control, especially large ryegrass Increases risk of crop injury, especially under cool, wet conditions COC generally not recommended
  7. Hoelon POST on Wheat and Weather Avoid cold, wet conditions Do not apply if temperature for preceding three days drops below 35 degrees
  8. Hoelon POST on Wheat Carriers and Tank Mixes Apply in water only; do not use nitrogen as carrier; reduced control Do not tank mix with other herbicides; reduced control May tank mix with Tilt and other fungicides; timing for Hoelon and fungicides do not coincide
  10. Alternatives to Control Hoelon-Resistant Ryegrass 1. Finesse 2. Axiom* 3. Clearfield system** 4. Mesosulfuron*** *Available under Section 18 for 2003/2004 **Varieties not available ***Not registered yet
  11. Alternatives to Control Hoelon-Resistant Ryegrass 1. Finesse
  12. Finesse 75 DF Premix of two SU’s 62.5% chlorsulfuron, 12.5% metsulfuron Good broadleaf control Suppression of ryegrass (variable results; dependent upon timely rain for activation) Applied PRE or POST; PRE usually best on ryegrass
  16. Finesse 75 DF Premix of two SU’s 62.5% chlorsulfuron, 12.5% metsulfuron Good broadleaf control Suppression of ryegrass (variable results) Rotational concerns
  17. Rotational Restrictions for Finesse Crop Interval STS soybeans 6 months Non-STS soybeans 18 months Cotton, corn 18 months NC experience: no problem with STS beans; variable results with non-STS beans
  19. Alternatives to Control Hoelon-Resistant Ryegrass 1. Finesse 2. Axiom
  20. Bleckly Bullock Burke Chattooga Crawford Dooly Early Elbert Franklin Glascock Hart Jefferson Johnson Laurens Lee Macon Peach Pulaski Randolf Schley Screven Sumter Taylor Terrell Twiggs Walker Washington Webster Wilkinson Georgia counties infested with diclofop-resistant Italian ryegrass.
  21. Axiom herbicide Mixture of two herbicides (4:1) 54.4% flufenacet + 13.6% metribuzin GA obtained Sect 18 exemption in fall 2002; applied for Sect 18 in fall 2003 Timing of application: wheat: emergence to 2- to 3-leaf stage ryegrass: before 1-leaf stage
  22. Axiom Why application to spike-stage wheat? Why not apply PRE (behind drill)?
  23. Axiom Why application to spike-stage wheat? Why not apply PRE (behind drill)? occasionally injury with PRE on sandy soils if heavy rain before wheat emergence
  24. Wheat Response to Axiom. Plains, GA, 2001.* *Axiom applied to emerged wheat caused no significant injury. Axiom 10 oz PRE Non-treated
  26. Axiom herbicide MUST BE ACTIVATED AND TIMELY
  27. Late-season Italian ryegrass control by Axiom applied at spike wheat. Plains and Tifton GA. 2001 and 2002. % Experiment designations, left to right: Tifton, 2001; Plains, 2002. Axiom applied at 9 oz/A. 84 52 Spike ryegrass 2-leaf ryegrass
  29. Hoelon-susceptible Italian ryegrass control by Axiom and Hoelon in Virginia. Avg. of three locations. H. P. Wilson, VPI&SU.
  30. Hoelon-resistant Italian ryegrass by Axiom in NC. Avg 2 locations, 2000-01.
  31. Hoelon-resistant Italian ryegrass control by Axiom and Hoelon in South Carolina. Avg. 3 locations. E. C. Murdock, Clemson Univ.
  32. Alternatives to Control Hoelon-Resistant Ryegrass 1. Finesse 2. Axiom 3. Clearfield system* 4. Osprey* *Future options
  33. Osprey GA petitioned for Section 18 emergency exemption in fall of 2002 and again Aug., 2003 EPA “has not had time to review the package and set a tolerance.”
  35. Late-season ryegrass control by Osprey applied timely in NC field studies. % Individual loactions (35 total) Average = 95%
  36. Broadleaf Weed Control Options Sencor Peak MCPA Express Buctril Harmony Extra Bronate 2,4-D Finesse Clarity
  37. 2,4-D 1. Controls most broadleaf weeds except chickweed, henbit, knawel. For wild garlic and wild onion, increase rate according to label. 2. Apply after fully tillered but before jointing in wheat, oats, barley, and rye
  38. Seedling Fully tillered Jointing Heading Flowering Soft dough Increasing tolerance Susceptibility of Small Grains to Phenoxy Herbicides As Affected by Growth Stage
  39. Wheat Response to 2,4-D. Macon County, 2000. 73 53 Wheat Stage at Time of Application Bushels/A
  40. Express Rate/timing: 0.25 to .33 oz POST, after 2 lf to flag leaf Adjuvant: 0.25% NIS Carrier: water or specific N Weeds: wild radish, wild mustard, Mixes: Mix with 0.25 to 0.5 pt/A of MCPA or 2,4-D Rotations: No rotation restriction Grains: Wheat, barley
  41. Express + MCPA 1) Wider window of application: After wheat has 2 tillers (some labels allow application after 2 leaf) but before jointing 2) Better control of henbit and chickweed compared to 2,4-D 3) Cost more than 2,4-D
  42. Harmony Extra Rate: 0.3 to 0.6 oz/A for wheat & barley (0.5 oz in general); 0.3 to 0.4 oz for oats Timing: 2-leaf until flag leaf visible Adjuvant: 0.25% NIS in water 0.125% NIS in nitrogen Weeds: Controls garlic and most broadleaf weeds Mixes: 2,4-D to improve cornflower, wild radish, and vetch Rotations: No restrictions of concern Grains: Wheat, barley, oats