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Living and Learning with Herbicide Resistant Weeds

AUTHOR
Eric P. Prostko and A. Stanley Culpepper
Extension Weed Specialists
University of Georgia
Tifton, GA

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TABLE OF CONTENTS
  1. Living and Learning with Herbicide Resistant Weeds
  2. UGA Weed Science Team Supporting Cast & Crew
  3. Palmer Amaranth in Georgia
  4. Do what must be done?
  5. Why Palmer Amaranth (Amaranthus palmeri)?
  6. Herbicide Resistance Concerns in Georgia
  7. Georgia counties confirmed to be infested with glyphosate-resistant Palmer amaranth
  8. GA Confirmed ALS-Resistant Palmer Sites
  9. 2008 Triazine Resistance Survey - Macon County
  10. Site 5 -- Atrazine Resistance Survey
  11. How did this happen to us?????
  12. Palmer Amaranth Biology
  13. Palmer amaranth seed production in Georgia from a single female plant
  14. R-Palmer amaranth seed longevity
  15. Influence of burial depth on Palmer amaranth emergence in Georgia
  16. Herbicide Resistant Weeds - Pollen Drift
  17. In-field Palmer amaranth pollen movement
  18. Cultural Practices
  19. No Deep Tillage vs Deep Turn
  20. Palmer amaranth seedling density as influenced by tillage.
  21. Photo
  22. Dryland Systems
  23. Irrigation in Georgia
  24. May-June 2008 Rainfall Distribution in Midville
  25. Residual herbicides must be activated on a timely basis with a reliable water source
  26. Dryland Systems
  27. Chemical Control Options
  28. Palmer Amaranth Control in Peanuts - Macon County, GA - 2007 (38 DAT)
  29. Palmer Amaranth Control in Peanuts - Macon County, GA - 2007 (38 DAT)
  30. Macon County -- GR Palmer Amaranth
  31. RR vs LL Corn - 2008
  32. Metribuzin Products on Soybeans
  33. GR-Pigweed Control in Soybeans - 2008
  34. GR-Palmer Amaranth Control in Soybeans - 2007
  35. Soybean varieties screened in 2008 that had adequate tolerance to Boundary 6.5EC, Canopy 75DG, and Sencor 75DG.
  36. GR-Pigweed Control in Soybeans - 2008 Macon County
  37. KIH-485
  38. GR-Palmer Amaranth Control in Soybeans with PRE’s (2008) - Macon Co.
  39. Under Utilized Modes of Action
  40. Halex GT in Field Corn - 2008
  41. Don’t forget!!! There are no steel resistant weeds!!!
  42. We are overusing the PPO inhibiting herbicides!!!!!!!!
  43. For More Weed Science Info: www.gaweed.com



SLIDE CONTENTS
  1. Living and Learning with Herbicide Resistant Weeds Eric P. Prostko and A. Stanley Culpepper Extension Weed Specialists Department of Crop & Soil Sciences
  2. UGA Weed Science Team Supporting Cast & Crew UGA Faculty Tim Grey (Tifton) Bill Vencill (Athens) Mark Czarnota (Griffin) Tim Murphy (Griffin) USDA-ARS Carroll Johnson Ted Webster Post-Doc’s Lynn Sosnoskie Valdosta State Univ. Richard Carter Technical Support Charlie Hilton Amy Davis Jesse Parker Kevin Baldree Administrative Dena Watson Graduate Students Rebekah Wallace Trey Cutts Student Workers Too many to mention but Very valuable to program
  3. Palmer Amaranth in Georgia
  4. Do what must be done?
  5. Why Palmer Amaranth (Amaranthus palmeri)? 38 species of Amaranthus in U.S. 27 species found in SE dioacious grows faster than other pigweeds (1-2” per day!!) more competitive than other pigweeds prolific seed producer seed to seed 9-12 WAE 2 generations/year herbicide tolerance
  6. Herbicide Resistance Concerns in Georgia glyphosate ALS herbicides Atrazine Multiple resistance Glyphosate + ALS
  7. Georgia counties confirmed to be infested with glyphosate-resistant Palmer amaranth. 2004 – 1 county 2005 – 2 counties 2006 – 7 counties 2007 – 10 counties 2008 – 6 so far 1-28-09
  8. GA Confirmed ALS-Resistant Palmer Sites
  9. 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)
  10. Site 5 – Atrazine Resistance Survey 0.1 1 5 10 0 Atrazine (qts/A) *Not resistant to Evik (ametryn) or Direx (diuron)
  11. How did this happen to us????? Economics drive farmer decisions No real long-term weed mgt. planning Farm logistics Overuse of glyphosate Overuse of Staple and Cadre Reduced herbicides rates Reduced tillage Reduction in use of residuals Dryland production systems
  12. Palmer Amaranth Biology How many seed? How long can the seed survive in the soil? Where does most of the germination occur? Pollen Drift
  13. # of seeds Palmer amaranth seed production in Georgia from a single female plant when competing with cotton for the season 450,000 Macon Co. 2006 *1,000,000 seed/plant (Keeley et al. 1987. Weed Science 35:199-204) California
  14. R-Palmer amaranth seed longevity Source: Dr. Lynn Sosnoskie - UGA
  15. Influence of burial depth on Palmer amaranth emergence in Georgia Source: Dr. Lynn Sosnoskie - UGA
  16. Herbicide Resistant Weeds Pollen Drift Off-site movement (wind, gravity, insects, man, animal) of resistance trait through pollen Pollen from resistant male fertilizes susceptible female to produce resistant progeny (seed) UGA researchers have documented GR-trait movement of at least 960’ (Palmer amaranth). Palmer Amaranth Pollen Source: Dr. Lynn Sosnoskie
  17. In-field Palmer amaranth pollen movement
  18. Cultural Practices Deep tillage Extreme cover crops
  19. No Deep Tillage Deep Turn No Herbicide Treatment
  20. Palmer amaranth seedling density as influenced by tillage.
  22. Dryland Systems
  23. Irrigation in Georgia Source: Kerry Harrison, UGA Extension Engineer
  24. May-June 2008 Rainfall Distribution in Midville Crops planted from May 21-June 21 did not receive enough rainfall to activate herbicides (0.26” total). June Rainfall = 0.62” which occurred as follows:12 (0.08”); 22 (0.36”); 26 (0.08”); 29 (0.10”)
  25. If residual herbicides are not activated on a timely basis with a reliable water source, pigweed control will be very difficult, maybe even impossible!
  26. Dryland Systems Growers need to think about mechanical herbicide incorporation Will help but not a guarantee Success will depend upon…… operator Implement Soil conditions
  27. Chemical Control Options Valor (flumioxazin) Reflex (fomesafen) Dual Magnum (S-metolachlor) Atrazine Liberty-Link (glufosinate) Sencor products (metribuzin) KIH-485
  28. Palmer Amaranth Control in Peanuts Macon County, GA – 2007 (38 DAT) NTC Valor SX 51WG @ 3 oz/A
  29. Palmer Amaranth Control in Peanuts Macon County, GA – 2007 (38 DAT) NTC Dual Magnum 7.62EC @ 1 pt/A
  30. 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
  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. Metribuzin Products on Soybeans Sencor Boundary Dual Magnum + Sencor Canopy Sencor + Classic Read label Know soil texture and OM Varieties rotations
  33. GR-Pigweed Control in Soybeans - 2008 SB-06-08 Macon County 48 DAP NTC Canopy 75DG @ 6 oz/A + Prowl H2O 3.8ASC @ 2.1 pt/A (PRE)
  34. GR-Palmer Amaranth Control in Soybeans - 2007 SB-01-07 Macon Co. 76 DAP NTC Gramoxone Inteon @ 3 pt/A + Boundary @ 1.8 pt/A + NIS @ 0.25% v/v (7 DBP) Touchdown Total @ 1.5 pt/A (26 DAP)
  35. Soybean varieties screened in 2008 that had adequate tolerance to Boundary 6.5EC (2 pt/A), Canopy 75DG (5 oz/A), and Sencor 75DG (6 oz/A). Ag South AGS 568 Asgrow H7242 Asgrow 4903 RR/STS Delta Pineland DP 5634 Delta Pineland DP 6568 Northrup King NKS 80P2 Northrup King NKS 76L9 Northrup King NKS 78G6 Pioneer 95Y40 Pioneer 95Y70 Pioneer 96M60 Pioneer 97M50 Southern States RT5951 Southern States RT4808 Vigoro V61N9 Vigoro V74N9
  36. GR-Pigweed Control in Soybeans – 2008 Macon County 90% Valor @ 3 oz/A; Envive @ 3 oz/A; Reflex @ 1 pt/A; Prefix @ 2 pt/A; Canopy @ 6 oz/A; Sencor @ 8 oz/A KIH-485 @ 4.2 oz/A; Dual Magnum @ 1 pt/A
  37. KIH-485 Pyroxasulfone Kumiai Developed for corn and soybeans PRE Herbicide Family Sulfonylioxazoline (?) Herbicide Mode of Action (?) plant growth inhibitor that affects apical meristem and coleoptile development of plants after seed germination Low use rates
  38. GR-Palmer Amaranth Control in Soybeans with PRE’s (2008) - Macon Co. NTC KIH-485 85WG @ 4.2 oz/A SB-05-08 48 DAT
  39. Under Utilized Modes of Action HPPD-inhibitors Mesiotrione (Callisto) Tembotrione (Laudis) Topramezone (Impact)
  40. Halex GT in Field Corn - 2008 Untreated CN-05-08 6/19/2008 83 DAP Halex GT 4.39L 4 pt/A + NIS (POST)
  41. Don’t forget!!! There are no steel resistant weeds!!!
  42. We are overusing the PPO inhibiting herbicides!!!!!!!! Resistance has already been reported in other areas!!! Common waterhemp 2001 (Kansas) 2002 (Illinois) 2003 (Missouri) Common ragweed 2005 (Delaware) Wild poinsettia 2004 (Brazil)
  43. For More Weed Science Info: www.gaweed.com eprostko@uga.edu 229-386-3328 (office) 229-392-1034 (cell)