Slide Presentation

TITLE    (click title to view slides)
2009 Field Corn Weed Management

AUTHOR
Eric P. Prostko
Extension Weed Specialist
Dept. Crop and Soil Sciences
UGA

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TABLE OF CONTENTS
  1. 2009 Corn Weed Control Update
  2. Herbicide Resistance Concerns for Field Corn
  3. Glyphosate Resistance Around the World (15 species)
  4. GA counties confirmed to be infested with glyphosate-resistant Palmer amaranth
  5. GA Confirmed ALS-Resistant Palmer Sites
  6. 2008 Triazine Resistance Survey Macon County
  7. A Closer Look
  8. Site 5 -- Atrazine Resistance Survey
  9. Cotton Herbicides/Corn Rotations
  10. Reflex Carryover in 2008 -- Early County
  11. Burndown Control Options
  12. Ryegrass Control - Burndown
  13. Annual Ryegrass Control with Roundup WM
  14. Conventional or RR or LL Systems?
  15. Conventional Systems
  16. Accent + Atrazine - 2008 (52 DAT)
  17. Why do you not want to spend the money on an Accent + Atrazine treatment in field corn?
  18. Corn Yield Response to Various POST Herbicide Treatments
  19. Conventional Weed Management Systems -- Many Pre-Mixes Available
  20. GR-Palmer Amaranth -- Bicep II Magnum 5.5 L
  21. Post-Directed Options for Field Corn
  22. U.S. Corn Acres Planted to Herbicide Resistant Hybrids
  23. Should you use the RR corn system?
  24. How would I use RR corn systems?
  25. Halex GT in Field Corn - 2008
  26. Corn Grain Yield As Influenced by Glyphosate Timing (35 locations)
  27. Texas Panicum Control At Harvest with Single or Split Applications of Roundup WM - II
  28. Corn Yield Response to Single or Split Applications of glyphosate
  29. Texas Panicum Control
  30. What about Liberty-Link Corn?
  31. RR vs LL Corn - 2008
  32. Morningglory Control in Corn
  33. Pigweed Control in Corn
  34. Corn Yield Losses Caused by Palmer Amaranth Plants When They Emerge with Crop
  35. This is what a 2" pigweed looks like!!!!
  36. GR-Palmer Amaranth -- Atrazine 4L
  37. GR-Palmer Amaranth Control in Field Corn July 24, 2008 (92 DAP)
  38. Sicklepod Control in Corn
  39. Nutsedge Control
  40. Tropical spiderwort (a.k.a. Benghal dayflower) Commelina benghalensis
  41. TSW in Georgia
  42. TSW Control in Field Corn
  43. Tropical Spiderwort Control in Field Corn
  44. Post-Harvest Control of Tropical Spiderwort
  45. Johnsongrass Control in Corn
  46. New (er) Products
  47. Callisto
  48. Callisto + Atrazine - 2008 (51 DAT)
  49. Status 56WG
  50. GR-Palmer Amaranth Control in Field Corn July 24, 2008 (92 DAP)
  51. Resolve Q
  52. Accent vs. Resolve Q (51 DAT)
  53. Laudis 3.5SC
  54. Laudis vs. Accent
  55. Generic Accent's (nicosulfuron)
  56. Optimum® GAT® Technology Glyphosate-ALS Tolerance
  57. Optimum® GAT® Field Corn
  58. Potential GAT Corn Products
  59. For More Weed Science Info -- www.gaweed.com



SLIDE CONTENTS
  1. 2009 Corn Weed Control Update Eric P. Prostko Extension Weed Specialist Dept. Crop & Soil Sciences UGA
  2. Herbicide Resistance Concerns for Field Corn glyphosate ALS herbicides Accent, Basis Gold, Beacon, Exceed, Lightning, Option, Permit, Steadfast Atrazine
  3. Glyphosate Resistance Around the World (15 species) rigid ryegrass (1996)** goosegrass (1997) horseweed (2000)** Italian ryegrass (2001)** hairy fleabane (2003)** buckhorn plantain (2003) common ragweed (2004)** giant ragweed (2004)** Palmer amaranth (2005)** common waterhemp (2005)** johnsongrass (2005)** wild poinsettia (2005) sourgrass (2006) junglerice (2007) liverseedgrass (2008) ** 9/15 (60%) can be found in the US
  4. Georgia counties confirmed to be infested with glyphosate-resistant Palmer amaranth. 2004 – 1 county 2005 – 2 counties 2006 – 7 counties 2007 – 10 counties 2008 – screening in progress
  5. GA Confirmed ALS-Resistant Palmer Sites
  6. 2008 Triazine Resistance Survey Macon County 4/20 sites resistant to 10X rate (4,5,15,20) 6/20 sites took 5 qts/A to kill (3,6,8,14,17,19)
  7. A Closer Look (4, 5, 15, 20)
  8. Site 5 – Atrazine Resistance Survey 0 0.1 1 5 10 0 Atrazine (qts/A)
  9. Cotton Herbicides/Corn Rotations Cadre: 9 months Strongarm: 18 months Staple: 9-10 months Envoke: 210 days Reflex: 10 months Reflex Staple
  10. Reflex Carryover in 2008 Early County
  11. Burndown Control Options glyphosate paraquat Ignite (glufosinate) tank-mixes with? 2,4-D atrazine others Aim, ET, Harmony Extra (14 DBP), Express (14 DBP), Clarity, Valor (14 DBP) Need a clean seed-bed at planting
  12. Ryegrass Control - Burndown Hard to kill with 1 shot Ryegrass is most susceptible to glyphosate when applied between boot and early flower stage of growth. Option # 1 Glyphosate @ 1.5 lb ai/A + atrazine 4L @ 3 pts/A Option #2 paraquat @ 0.47 lb ai/A – 2 WBP fb paraquat @ 0.47 lb ai/A + atrazine 4L @ 3 pts/A – at planting RR corn systems Accent???? 1.50 lb ai/A = 35 oz/A of 5.5 lb/gal or 48 oz/A of 4 lb/gal 0.47 lb ai/A = 30 oz/A of 2L or 20 oz/A of 3L
  13. Annual Ryegrass Control with Roundup WM Source: Lins et al. 2007. Weed Technology 21:602-605
  14. Conventional or RR or LL Systems?
  15. Conventional Systems Atrazine still THE major player in any system Prowl in cheap but ……. One of my favorites is Accent + Atrazine If Texas panicum is main problem many Pre-mixes
  16. Accent + Atrazine – 2008 (52 DAT) CN-12-08 Ponder Farm June 13, 2008 NTC Accent 75WG @ 0.67 oz/A Atrazine 4L @ 1.5 qt/A Peptoil @ 1% v/v 96 Bu/A 148 Bu/A
  17. Why do you not want to spend the money on an Accent + Atrazine treatment in field corn? Data from 24 comparisons from field trials conducted in Georgia from 2001-2008. At $3.00 to $4.00/bu, it only takes a 5-7 Bu/A increase to pay for the treatment!!! +56 Bu/A
  18. Corn Yield Response to Various POST Herbicide Treatments Average of 2 tests conducted in 2003 and 2004 (Tifton, Attapulgus) Where Texas panicum is the main weed problem Atrazine PRE @ 1.5 qt/A e d ab a b a a a
  19. Conventional Weed Management Systems Many Pre-Mixes Available Bicep II Magnum (atrazine + Dual II Magnum) Lariat/Bullet (atrazine + Lasso) Lexar (atrazine + Dual Magnum + Callisto) many others preemergence a good choice if many different weed species are present need 0.5” of rainfall or irrigation within 7-10 days for activation
  20. NTC Bicep II Magnum 5.5L @ 2.1 qt/A PRE Macon County – GR Palmer Amaranth June 24, 2008 – 60 DAP CN-01-08
  21. Post-Directed Options for Field Corn Evik Gramoxone Inteon/Firestorm Lorox/Linex Aim tropical spiderwort pigweeds morningglory
  22. U.S. Corn Acres Planted to Herbicide Resistant Hybrids Source: NASS Includes stacked
  23. Should you use the RR corn system? advantages easy Broad spectrum Reduced drift concerns No soil insecticide issues disadvantages No residual over-reliance on a single product Herbicide resistance concerns Volunteer in other RR crops Glyphosate price increases
  24. How would I use RR corn systems? Must use atrazine or another residual 2 applications of glyphosate 1st application: 21-28 DAP + atrazine (1.5-2.0 qt/A) 2nd application: 35-40 DAP Sequence (Dual Magnum + Touchdown) Expert (Dual Magnum + Atrazine + Touchdown) Halex GT (Callisto + Dual Magnum + Touchdown) Do not forget to include extra seed costs/A in your budgets! Irrigated @ 30,000/A = $11.00/A Dryland @ 18,000/A = $7.00/A
  25. Halex GT in Field Corn - 2008 Untreated CN-05-08 6/19/2008 83 DAP Halex GT 4.39L 4 pt/A + NIS (POST)
  26. Corn Grain Yield As Influenced by Glyphosate Timing (35 locations) Gower et al., 2003. Weed Technology 17:821-828.
  27. Texas Panicum Control At Harvest with Single or Split Applications of Roundup WM - II CN-04-04 (Attapulgus) Untreated Roundup WM @ 22 ozs/A 21 DAP Roundup WM @ 22 ozs/A 21 + 35 DAP
  28. Corn Yield Response to Single or Split Applications of glyphosate (4.5 lb ae/gal) @ 22 ozs/A. Average of 7 locations (2003-06) DKC67-60RR
  29. Texas Panicum Control OR About 30% of the time, Accent has provided better control of Texas panicum But, yields have not been different.
  30. What about Liberty-Link Corn? Glufosinate Liberty 1.67SL (30 oz/A) Ignite 2.34SL (22 oz/A) No tech fee up to 24” tall corn or V7 Tank-mix with atrazine Liberty ATZ good on morningglory, Texas millet, sicklepod Hybrid performance Garst 8353CB/LL, Hytest 7729Hx/LL, Pioneer 33M57
  31. RR vs LL Corn - 2008 Untreated Roundup W-Max @ 22 oz/A Atrazine @ 1.5 qt/A Prowl H2O @ 2.1 pt/A (POST) Ignite 2.34 SL @ 23 oz/A Atrazine @ 1.5 qt/A Prowl H2O @ 2.1 pt/A AMS @ 3 lb/A (POST) CN-11-08 6/17/2008 81 DAP
  32. 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 Liberty-Link Corn Systems split applications of glyphosate (RR corn) * 1st application + atrazine Harvest Aids Aim or Sodium Chlorate
  33. Pigweed Control in Corn preemergence Atrazine Dual/generics Outlook postemergence Atrazine Accent Callisto Laudis 2,4-D Permit Aim glyphosate (RR corn) Status Timing is critical!
  34. Corn Yield Losses Caused by Palmer Amaranth Plants When They Emerge with Crop Massinga et al. 2001. Weed Sci. 49:202-208
  35. This is what a 2” pigweed looks like!!!!
  36. NTC Atrazine 4L @ 1 qt/A – PRE Atrazine 4L @ 1.5 qt/A – 30 DAP Peptoil @ 1% v/v – 30 DAP Macon County – GR Palmer Amaranth June 24, 2008 – 60 DAP CN-01-08
  37. GR-Palmer Amaranth Control in Field Corn July 24, 2008 (92 DAP) NTC Roundup PowerMax (22 oz/A) Atrazine (2 qt/A) Prowl H20 (2.1 pt/A) EPOST (21 DAP) CN-01-08
  38. Sicklepod Control in Corn Conventional Systems Atrazine 2,4-D Clarity Status Herbicide-Resistant RR corn system LL corn system
  39. Nutsedge Control not very competitive 800 plants/100 row feet only reduce yields by 2% Eradicane or Sutan - PPI Dual II Magnum or generic – PRE Glyphosate – RR corn Split applications Basagran Permit
  40. Tropical spiderwort (a.k.a. Benghal dayflower) Commelina benghalensis tropical Africa native annual or perennial seeds and rhizomes above and below ground flowers 1,600 seeds/plant alternate host of southern root-knot nematode Reservoir for southern stem blight (white mold)
  41. TSW in Georgia 2004: 29 counties (light blue) 2005: 5 counties (black) 2006: 6 counties (dark blue) 2007: 2 counties (yellow) 2008: 2 counties (red)
  42. TSW Control in Field Corn Depends on planting date 2,4-D or Aim – POST Sequence or Expert in RR corn Aim/Gramoxone/Evik + Dual Magnum – layby Post-harvest may be more important than in-crop Tillage 2 applications of 2,4-D, Gramoxone, or Aim
  43. Tropical Spiderwort Control in Field Corn Untreated Aim 2EC @ 1.5 ozs/A Dual Magnum 7.62EC @ 1.33 pt/A Herbimax @ 1% v/v 34 DAT CN-01-05
  44. Post-Harvest Control of Tropical Spiderwort Untreated 2,4-D @ 1.5 pt/A POST1 + POST 2 ($14.41/A) POST1: 8-10” tall COMBE POST2: 2 weeks later Photo 1 week after POST2
  45. Johnsongrass Control in Corn Accent no OP soil insecticide hybrid tolerance to Accent hybrid resistance to MDMV Glyphosate in RR corn
  46. New (er) Products Callisto Status Resolve Q Laudis Generic Accent’s
  47. Syngenta POST 3 oz/A + COC + UAN or AMS ($12-13/A) Up to 30” tall or 8-leaf corn Palmer amaranth up to 5” Tank-mix with atrazine also good on horsenettle Interaction with OP’s Weak on PANTE and CASOB Good option for atrazine, ALS and GR-Palmer Unique mode of action “Bleacher”
  48. Callisto + Atrazine – 2008 (51 DAT) CN-03-08 06/13/08 NTC Callisto 4SC @ 3 oz/A Atrazine 4L @ 2 qt/A Peptoil @ 1% v/v
  49. Status 56WG BASF dicamba + diflufenzopyr + isoxadifen “Super” Banvel + safener POST 5-10 oz/A ($2.20/oz) broadleaf weed control
  50. GR-Palmer Amaranth Control in Field Corn July 24, 2008 (92 DAP) NTC Status 56WG @ 5 oz/A NIS @ 0.25% v/v AMS @ 3 lb/A EPOST (21 DAP) CN-01-08
  51. Resolve Q Dupont Resolve (rimsulfuron) + Harmony (thifensulfuron) + safener (isoxadifen) 1.25 oz/A + COC or NIS + N POST control but has some residual 20” corn or 7 collars Is it as good as Accent on Texas millet in GA????????
  52. Accent vs. Resolve Q (51 DAT) CN-12-08 Ponder Farm June 13, 2008 NTC Accent 75WG @ 0.67 oz/A Atrazine 4L @ 1.5 qt/A Peptoil @ 1% v/v Resolve Q @ 1.25 oz/A Atrazine 4L @ 1.5 qt/A Peptoil @ 1% v/v
  53. Laudis 3.5SC Bayer Tembotrione + isoxadifen (safener) “Bleacher” POST 3 oz/A Emergence to V8 stage Requires use of MSO and nitrogen Good for pigweed management Also has crabgrass and BL signalgrass listed on label Is it as good as Accent on Texas millet?
  54. Laudis vs. Accent CN-09-08 Attapulgus Farm June 12, 2008 53 DAT NTC Laudis 3.5SC @ 3 oz/A Atrazine 4L @ 1.5 qt/A MSO @ 1% v/v UAN-28% @ 1.5 qt/A Accent 75DG @ 0.67oz/A Atrazine @ 2 qt/A Peptoil @ 1% v/v
  55. Generic Accent’s (nicosulfuron) NIC-IT Cheminova Formulated as 2SC instead of 75WDG Use rate is 2 oz/A Samson UPI 0.33 ai/gal (SC) Use rate is 12 oz/A Both have not yet been tested in GA
  56. Optimum® GAT® Technology Glyphosate-ALS Tolerance Dupont/Pioneer Glyphosate metabolic inactivation mechanism Gene shuffling Insensitive ALS enzyme Soybean 2009/2010 demonstration plots 2011 Commercial introduction Field corn (2010?) What does it bring to the table? Flexibility
  57. Optimum® GAT® Field Corn NTC Touchdown Total - 24 oz/A Classic – 0.188 oz/A Harmony GT – 0.25 oz/A Express – 0.125 oz/A Callisto – 2.5 oz/A All applied at V3 stage CN-06-08 6/13/2008 16 DAT
  58. Potential GAT Corn Products Diligent Classic + Resolve + Valor Freestyle Classic + Harmony + Express Instigate Classic + Resolve + Callisto Traverse Classic + Resolve Trigate Resolve + Express + Callisto
  59. For More Weed Science Info www.gaweed.com www.gaweed.com