Slide Presentation

TITLE    (click title to view slides)
2007 Corn Weed Control Update

AUTHOR
Eric P. Prostko
Extension Weed Specialist
University of Georgia
Tifton, GA

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TABLE OF CONTENTS
  1. 2007 Corn Weed Control Update
  2. Changes in 2007 Pest Control Handbook
  3. Burndown Control Options
  4. Ryegrass Control - Burndown
  5. Conventional or RR Systems?
  6. Conventional Systems
  7. Why do you not want to spend the money on an Accent + Atrazine treatment in field corn?
  8. Corn Yield Response to Various POST Herbicide Treatments
  9. Conventional Weed Management Systems - Many Pre-Mixes Available
  10. Post-Directed Options for Field Corn
  11. Should you use the RR corn system?
  12. How would I use RR corn systems?
  13. Texas Panicum Control At Harvest with Single or Split Applications of Roundup WM - II
  14. Corn Yield Response to Single or Split Applications of glyphosate
  15. Glyphosate Resistance Around the World (12 species)
  16. 2005 GR-Pigweed Survey
  17. Preserving the Value of Glyphosate
  18. New Products that have been tested
  19. Callisto
  20. Texas Panicum Control
  21. What about Liberty-Link Corn?
  22. Don’t Forget Liberty-Link Corn!
  23. Morningglory Control in Corn
  24. Pigweed Control in Corn
  25. Sicklepod Control in Corn
  26. Nutsedge Control
  27. Tropical spiderwort (a.k.a. Benghal dayflower) Commelina benghalensis
  28. TSW in Georgia
  29. TSW Control in Field Corn
  30. Post-Harvest Control of Tropical Spiderwort
  31. Post-Harvest Control of Tropical Spiderwort
  32. Johnsongrass Control in Corn
  33. New Products Tested in 2006
  34. Resolve 25WG (rimsulfuron) Injury to Field Corn
  35. Stout Injury on Pioneer 3167 - 6 DAT
  36. Future Products
  37. www.gaweed.com



SLIDE CONTENTS
  1. 2007 Corn Weed Control Update Eric P. Prostko Extension Weed Specialist Department of Crop & Soil Sciences - UGA
  2. Changes in 2007 Pest Control Handbook Added Sequence Added Expert Added generic metolachlors but still included the following warning: The generic formulations of metolachlor (Parallel, Stalwart, Me-Too-Lachlor) have not provided the same length of residual control of certain weeds as similar rates of Dual Magnum formulations in some UGA field trials. Added Firestorm Added rain-free periods Added a burndown table for reduced tillage. Added Propel Post-harvest control rec's for tropical spiderwort Table of metolachlor and s-metolachlor products Added Callisto to POST section Table for ALS/GR-resistant pigweed
  3. Burndown Control Options glyphosate Paraquat Ignite (glufosinate) tank-mixes with? 2,4-D atrazine Need a clean seed-bed at planting
  4. Ryegrass Control - Burndown Hard to kill with 1 shot Option # 1 Glyphosate @ 1.125 lb ae/A + atrazine @ 3 pts/A Option #2 Gramoxone Inteon @ 1.9 pts/A – 2 WBP fb Gramoxone Inteon @ 1.9 pts/A + atrazine @ 3 pts/A - planting RR corn systems Accent????
  5. Conventional or RR Systems?
  6. 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
  7. Why do you not want to spend the money on an Accent + Atrazine treatment in field corn? Data from 18 irrigated weed control trials conducted in Georgia from 2001-2006. At $2.00 to 3.00/bu, it only takes a 9 to 14 bu/A increase to pay for the treatment!!!
  8. 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
  9. 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
  10. Post-Directed Options for Field Corn Evik Gramoxone Inteon/Firestorm Lorox/Linex Aim tropical spiderwort pigweeds morningglory
  11. Should you use the RR corn system? advantages Inexpensive 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
  12. How would I use RR corn systems? If you are unwilling to use a PRE application of atrazine or something else…. 2 applications of glyphosate 1st application: 21-28 DAP + atrazine (1.5-2.0 qt/A) 2nd application: 35-40 DAP Sequence (s-metolachlor + glyphosate) Expert (s-metolachlor + atrazine + glyphosate) Do not forget to include extra seed costs/A in your budgets! Irrigated @ 30,000/A = $12-13.00/A Dryland @ 18,000/A = $7-8.00/A
  13. 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
  14. 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
  15. Glyphosate Resistance Around the World (12 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) ** Can be found in the US
  16. 2005 GR-Pigweed Survey 47 of 100 sites With Confirmed Resistance to glyphosate!! 1 location in Lee County Confirmed in 2006 *
  17. Preserving the Value of Glyphosate tank-mix 2,4-D in burndown when glyphosate will be used in-crop Consider paraquat or Ignite if appropriate Alternate glyphosate use with other herbicide modes of action Tank-mix with atrazine Use other practices such as cultivation Do not allow weed escapes to produce seed
  18. New Products that have been tested
  19. Syngenta POST 3 oz/A + COC + UAN or AMS ($13-15/A) Up to 30” tall or 8-leaf corn Palmer amaranth up to 5” If 2,4-D is undesirable or ALS-resistance Tank-mix with atrazine also good on horsenettle Interaction with OP’s
  20. Texas Panicum Control OR About 30% of the time, Accent has provided better control of Texas panicum But, yields have not been different.
  21. What about Liberty-Link Corn? Glufosinate Liberty (corn) Ignite (cotton) 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 2007 Rebate Program * Up to $6.25/A
  22. Don’t Forget Liberty-Link Corn! Untreated Liberty 1.67SL @ 32 ozs/A Atrazine @ 90WG @ 1.0 lb/A AMS @ 3 lbs/A Applied 26 DAP CN-10-06 (Croplan Genetics 731 HX/LL) Ponder Farm 52 DAP 83 Bu/A 114 Bu/A
  23. Morningglory Control in Corn as much atrazine as possible 1.0 lb/A – PRE fb 1.5 lb/A – POST small grain rotations tank-mix with Aim (POST) 2,4-D, Clarity Liberty-Link Corn Systems split applications of glyphosate (RR corn) * 1st application + atrazine
  24. Pigweed Control in Corn preemergence Atrazine Dual/generics Outlook postemergence Atrazine Accent Callisto 2,4-D Permit Aim glyphosate (RR corn) Timing is critical!
  25. Sicklepod Control in Corn Conventional Systems Atrazine 2,4-D Clarity Herbicide-Resistant RR corn system LL corn system
  26. 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
  27. 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)
  28. TSW in Georgia * confirmed in 29 counties by GA Dept. of Ag and UGA in 2004 (light blue) * identified in 4 more counties in 2005 (black) *identified in 6 more counties in 2006 (dark blue)
  29. 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
  30. 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
  31. Post-Harvest Control of Tropical Spiderwort Untreated Gramoxone Inteon @ 1 qt/A + COC POST1 + POST2 ($25.40/A) POST1: 8-10” tall COMBE POST2: 2 weeks later Photo 1 week after POST2
  32. Johnsongrass Control in Corn Accent no OP soil insecticide hybrid tolerance to Accent hybrid resistance to MDMV Glyphosate in RR corn
  33. New Products Tested in 2006 Impact (toprazamene) Amvac POST Poor control of Texas panicum and sicklepod Resolve (rimsulfuron) DuPont PRE and POST Crop Injury problems Stout (Accent + Harmony GT) DuPont POST Crop Injury problems
  34. Resolve 25WG (rimsulfuron) Injury to Field Corn 1.0 oz/A Applied PRE Pictures @ 18 DAT
  35. Stout Injury on Pioneer 3167 - 6 DAT CN-08B-06 Attapulgus, GA
  36. Future Products KIH-485 Kumiai similar activity to Dual and Prowl but different structure and lower use rates good on Palmer amaranth Not yet been tested in Georgia Source: Steele et al. 2005. Weed Technology 19:866-869
  37. www.gaweed.com