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Weed Control Update for Wheat

Weed Control Update for Wheat. Managing Ryegrass. Managing Ryegrass in Wheat Currently available: Finesse Hoelon Sencor Axiom In development: Mesosulfuron. Rates of Hoelon POST on wheat and barley. Ryegrass size pt Hoelon 1- to 3-leaf 1.33 pt

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Weed Control Update for Wheat

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  1. Weed Control Update for Wheat Managing Ryegrass

  2. Managing Ryegrass in Wheat • Currently available: Finesse • Hoelon • Sencor • Axiom • In development: Mesosulfuron

  3. Rates of Hoelon POST on wheat and barley 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

  4. Timing Hoelon POST Wheat: Before first node (jointing) of wheat

  5. Use of adjuvants with Hoelon POST: 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.

  6. Precautions on Hoelon label: 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

  7. Tank mixing Hoelon with other herbicides: Don’t do it; will lead to antagonism.

  8. Sequential applications of Hoelon and broadleaf herbicides: Do not apply 2,4-D within 5 days of Hoelon application

  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. Hoelon-resistant Ryegrass Estimated percentage in GA: ??????????????

  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 soilorganic 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. 26 4 9 11 8 10 27 3 12 5 29 13 21 17 25 23 1 14 2 20 18 16 6 22 28 19 24 15 7 Georgia counties infested with diclofop-resistant Italian ryegrass. • 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

  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.* Non-treated Axiom 10 oz PRE *Axiom applied to emerged wheat caused no significant injury.

  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. 26 DAP 98 95 80 73 % injury

  25. Late-season Italian ryegrass control by Axiom applied at spike wheat. Plains and Tifton GA. 2001 and 2002. 84 % 52 Spike ryegrass 2-leaf ryegrass Experiment designations, left to right: Tifton, 2001; Plains, 2002. Axiom applied at 9 oz/A.

  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. 99 93 94 95 % 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.

  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. Susceptibility of Small Grains to Phenoxy Herbicides As Affected by Growth Stage Soft dough Fully tillered Jointing Increasing tolerance Seedling Heading Flowering

  38. Wheat Response to 2,4-D. Macon County, 2000. 73 Bushels/A 53 Wheat Stage at Time of Application

  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

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