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

AUTHOR
Stanley Culpepper
University of Georgia

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TABLE OF CONTENTS
  1. Weed Control Update for Wheat
  2. Managing Ryegrass in Wheat
  3. Rates of Hoelon POST on wheat and barley
  4. Timing Hoelon POST
  5. Use of adjuvants with Hoelon POST
  6. Precautions on Hoelon label
  7. Tank mixing Hoelon with other herbicides
  8. Sequential applications of Hoelon and broadleaf herbicides
  9. Hoelon Tank Mixes in Wheat
  10. Hoelon-resistant Ryegrass
  11. Alternatives to Hoelon
  12. Using Sencor in Wheat
  13. Cultivar Wheat Screening Trial
  14. Sencor Rates Limited by Soil Types
  15. Sencor Rates Limited by Soil Types
  16. Sencor Efficacy on Ryegrass
  17. Alternatives to Hoelon
  18. Axiom 68 DF
  19. Georgia counties infested with diclofop-resistant Italian ryegrass
  20. Section 18 Granted for Axiom
  21. Experiment at Griffin, GA during 2000/2001 season
  22. Wheat Response to Axiom. Plains, GA, 2001.
  23. Section 18 Granted for Axiom
  24. Ryegrass Response to Axiom.
  25. Late-season Italian ryegrass control by Axiom applied at spike wheat.
  26. Hoelon is still more effective than Axiom on non-Hoelon resistant ryegrass if a timely application is made
  27. Alternatives to Hoelon
  28. Ryegrass Response to Mesosulfuron
  29. Late-season Italian ryegrass control by mesosulfuon plus iodosulfuron applied postemergence.
  30. Weed Control Update for Wheat
  31. Broadleaf Weed Control Options
  32. Harmony Extra
  33. Express
  34. Express
  35. MCPA
  36. 2,4-D
  37. Susceptibility of Small Grains to Phenoxy Herbicides
  38. Wheat Response to 2,4-D.
  39. Wild garlic
  40. Wild garlic Control in Wheat
  41. Wild radish size response to grain herbicides
  42. Preharvest Herbicide Options for Small Grains



SLIDE CONTENTS
  1. Weed Control Update for Wheat Managing Ryegrass
  2. Managing Ryegrass in Wheat Currently available: Finesse Hoelon Sencor Axiom In development: Mesosulfuron
  3. Ryegrass size pt Hoelon 1- to 3-leaf 1.33 pt 3- to 4-leaf 1.33 to 2 pt 5-leaf to 2 tiller 2 to 2.67 pt Rates of Hoelon POST on wheat and barley
  4. Wheat: Before first node (jointing) of wheat Timing Hoelon POST
  5. Wheat: Can add 1 to 2 pt/acre COC. Suggested only on large grass or dry conditions. Will increase risk of injury. Do not add if cool and wet. Do not use silicones or MSO. Use of adjuvants with Hoelon POST:
  6. Do not apply if one or more conditions exist: Cold temperature: Anytime during 72 hr preceding application temperature drops below 35 degrees Delay application if freezing temperature predicted within 3 days of application Soil moisture: Moisture at or above field capacity Precautions on Hoelon label:
  7. Don’t do it; will lead to antagonism. Tank mixing Hoelon with other herbicides:
  8. Do not apply 2,4-D within 5 days of Hoelon application Sequential applications of Hoelon and broadleaf herbicides:
  9. Hoelon Tank Mixes in Wheat Label: may tank mix with liquid nitrogen fertilizer (28 to 32%) if the timing for use is compatible UGA recommends no herbicide tank 1) often to late to control weeds 2) injury potential increased 3) reduced control of ryegrass
  10. Estimated percentage in GA: ?????????????? Hoelon-resistant Ryegrass
  11. Alternatives to Hoelon Currently available: Finesse Hoelon Sencor Axiom In development: Mesosulfuron
  12. Using Sencor in Wheat Metribuzin-tolerant cultivar AgriPro Mason Hunter Clark Coker 9134 Pioneer 2684
  13. Cultivar Wheat Screening Trial; Plains 2001.
  14. Sencor Rates Limited by Soil Types Label: wheat 2 leaf - 2 tiller soil organic matter texture 0.75 2.0 coarse 0.094 lb ai 0.125 lb ai medium 0.125 lb ai 0.125 lb ai fine 0.125 lb ai 0.1875 lb ai UGA research shows we need 0.25 to 0.31 lb ai per acre when wheat is 3 to 4 leaf
  15. Sencor Rates Limited by Soil Types Need ideal weather conditions: warm (not hot) periods with optimum wheat and ryegrass growth no significant rainfall for several days Do not add crop oil May add nonionic surfactant but may see ~10% additional injury
  16. Sencor Efficacy on Ryegrass Locations 1* 2* 3* 4** 5* Sencor (0.25 - 0.31 lb ai) 80 87 78 53 97 Hoelon (0.5 - 0.75 lb ai) 94 93 94 69 26* *Ryegrass 3 leaf or less **Ryegrass 1 tiller or larger *Hoelon resistant ryegrass present.
  17. Alternatives to Hoelon Currently available: Finesse Hoelon Sencor Axiom In development: Mesosulfuron
  18. Axiom 68 DF Section 18 granted for 29 GA counties
  19. 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.
  20. Section 18 Granted for Axiom New wheat herbicide by Bayer 54.4% flufenacet + 13.6% metribuzin 6 to 10 oz of product on medium or fine textured soils (8 to 10 oz for most soils) Do not apply preemergence
  21. Axiom at 8 oz PRE Non-treated Experiment at Griffin, GA during 2000/2001 season
  22. Wheat Response to Axiom. Plains, GA, 2001.* *Axiom applied to emerged wheat caused no significant injury. Axiom 10 oz PRE Non-treated
  23. Section 18 Granted for Axiom New wheat herbicide by Bayer 54.4% flufenacet + 13.6% metribuzin 6 to 10 oz of product on medium or fine textured soils (8 to 10 oz for most soils) Do not apply preemergence Apply to spike wheat hopefully before ryegrass emerges (must be activated by rainfall or irrigation)
  24. Ryegrass Response to Axiom. Averaged over Plains and Tifton, GA 2001/2002. % injury 95 73 98 80 26 DAP
  25. 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
  26. Hoelon is still more effective than Axiom on non-Hoelon resistant ryegrass if a timely application is made
  27. Alternatives to Hoelon Currently available: Finesse Hoelon Sencor Axiom In development: Mesosulfuron
  28. Ryegrass Response to Mesosulfuron. North Carolina, 2001. Non-treated Mesosulfuron POST
  29. Late-season Italian ryegrass control by mesosulfuon plus iodosulfuron applied postemergence. Plains and Tifton GA. 2001 and 2002. % Experiment designations, left to right: wheat3-01; wheat5-01; wheat6-01; Average. Mesosulfuron applied at 12.5 g ai/ha mixed with iodosulfuron at 2.5 g ai/ha. 99 93 94 95
  30. Weed Control Update for Wheat Managing Ryegrass
  31. Broadleaf Weed Control Options Sencor Peak MCPA Express Buctril Harmony Extra Bronate 2,4-D Finesse Clarity
  32. 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
  33. Express 1. effective on wild radish, wild mustard, and other broadleaf weeds 2. 2-lf stage until just before flag leaf wheat and barley 3. less effective than Harmony Extra on garlic, henbit, shepherdsurse, and wild radish. No rotational restrictions of concern 4. tank mix with 0.125 to 0.375 lb ai of 2,4-D or MCPA
  34. 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: Less effective than Harmony Extra on garlic, henbit, and shepherdsurse Mixes: Mix with 0.25 to 0.5 pt/A of MCPA or 2,4-D Rotations: No rotation restriction Grains: Wheat, barley
  35. MCPA 1.) Similar to 2,4-D, 0.5 to 1 pt/A POST 2.) After wheat has 2 tillers (some labels allow application after 2 leaf) but before jointing (oats should be fully tillered) 3.) Wheat, barley, rye, oats
  36. 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
  37. Seedling Fully tillered Jointing Heading Flowering Soft dough Increasing tolerance Susceptibility of Small Grains to Phenoxy Herbicides As Affected by Growth Stage
  38. Wheat Response to 2,4-D. Macon County, 2000. 73 53 Wheat Stage at Time of Application Bushels/A
  39. Wild garlic Not a yield problem Major quality problem
  40. Wild Garlic Control in Wheat Harmony Extra: 0.5 to 0.6 oz garlic < 12”, 2-4” new growth Peak: 0.25 to 0.5 oz garlic < 6-8” rotational concerns 2,4-D ester: 2 pt; after tillering, before jointing injurious to wheat
  41. Wild radish size response to grain herbicides. Herbicide 0-8 inch 8-14 inch bolting 2,4-D 90+ 70-80% <50% MCPA 90+ 50-70% <30% MCPA + Express 90+ 80-85% <65% Peak 90+ 75-85% <50% Express 90+ 50% <50% Harmony Extra 90+ 50% <50%* *At some stage after bolting becomes more susceptible.
  42. Preharvest Herbicide Options for Small Grains Crop Herbicides Rate Remarks Wheat & 2,4-D amine* 1-2 pt Hard dough stage or later. Barley, Rye 2,4-D ester* 1-2 pt Oats 2,4-D acid/ester 1-2 pt Wheat Glyphosate 0.5 to After hard dough stage 1.5 lb ai (30% or less moisture), at least 7 days before harvest. Not for seed wheat. *3.8 L formulations