1. 2011: Impact of cover crop residue and tillage on the control of glyphosate-resistant Palmer amaranth

2. Staple + Reflex + Direx PRE Roundup WMax + Parrlay POST Direx + MSMA Layby Palmer amaranth control before and after GR Palmer resistance in cotton! Roundup

3. Georgia counties confirmed to be infested with glyphosate-resistant Palmer amaranth. 2004 – 1 county 2005 – 2 counties 2006 – 7 counties 2007 – 11 counties 2008 – 18 counties 2009 – 13 counties

4. 230 K 250 28 K 309 K Giant ragweed 450 K Number of Seed Produced per Plant Glyphosate-Resistant Weeds in US Ragweed = Harrison et al. 2001; johnsongrass = Warwick and Black (1983); horseweed = Regehr and Bazzaz (1979); waterhemp = Nordby and Hartzler (2004); Palmer amaranth = Macrae et al (2009). Johnson -grass HorseweedWaterhempPalmer amaranth

5. Palmer amaranth seed production allows for rapid field domination Year 1Year 3 to 4

6. Role of pollen movement and gene-flow in the spread of herbicide resistance

7. In-field pollen movement

8. Amaranthus rudis Amaranthus palmeri Tennessee Missouri Illinois Mississippi Georgia S Carolina N Carolina Alabama Louisiana Arkansas GR pigweed in the mid-south and southeast Steckel 2010

9. Can not survive with herbicides alone any longer

10. York 2010 Hand Weeding 2010: Herbicide input: $90 million

11. York 2010 Hand Weeding Over $16 million spent during 2010 ($23.70 on 53% of our acres) Over $15 million spend during 2009 92% of GA growers handweeding 53% of the 2010 crop

12. Few growers Most growers by far Grower mentality of tillage vs. conservation tillage

13. 5 % acres *Average of Macon, Taylor, Sumpter, Schley, and Dooly counties Herbicide Incorp. 0 Impact of GR Palmer amaranth in Georgia counties with severe infestations.*

14. Tillage in Cotton During 2010 %PPI tillageGA Counties # 00 1-9 Worth, Pualski, Tift, Berrien, Echols, Turner, Brooks, Pierce, Marion, Grady, 10 10-19 Emanual, Montgomery, Atkins, Coffee, Lowndes, Dooly, Wilcox, Thomas, Crisp, Schley, Webster 11 20-29Bullock, Jefferson, Treutlen, Wheeler, Daugherty5 30-50 Effingham, Telfair, Tattnall, Dodge, Toombs, Jeff Davis, Bleckly, Early, Lanier, Irwin, Colquitt, Lee 13 >50Jenkins, Johnson, Washington, Screven, Wayne, Laurens, Randolf, Decatur, Seminole, Miller, Taylor Ben Hill 12

15. Although the agricultural community is committed to the benefits of conservation tillage, survival of the family farm is more critical. Thus, understanding when tillage is required and determining how to implement tillage to compliment conservation tillage systems while having minimal impacts on the environment are needed if both the family farm and conservation tillage are expected to survive the threat of herbicide resistant weed. LONG TERM GOAL

16. Objective Develop an economically effective integrated program for the control of GR Palmer amaranth in cotton.

17. Roundup applied three times starting on ½ Palmer provided no control

18. Four Tillage Options Deep Inversion (12 to 16 inches) Strip into weeds

19. Four Tillage Options Deep inversion followed by Rye Heavy residue (1.5 bu/A)

22. Staple + Reflex + Direx PRE Roundup WMax + Parrlay POST Direx + MSMA Layby Palmer amaranth control of 95% achieved by herbicide program!

23. GR Palmer amaranth control by tillage and cover crop residue. 2009 & 2010. 21 DAP.* 0 d 50 c 60 b Weeds *No herbicide Inversion + rye Deep inversion 75 a Rye %

24. In the rye, control loss was in the strip

25. GR Palmer amaranth control by tillage, cover crop residue, and herbicides. 2009 & 2010 At harvest.* 76 b 78 b Weeds *RR System: Diuron + Reflex + Staple fb Roundup + Parrlay fb Direx + MSMA Inversion + rye Deep inversion 94 a Rye % 59 c

26. Staple + Reflex + Direx PRE Roundup WMax + Parrlay POST Direx + MSMA Layby WeedsDeep Tillage Palmer amaranth response to deep tillage. Macon County, GA. 2009.

27. Staple + Reflex + Direx PRE Roundup WMax + Parrlay POST Direx + MSMA Layby Weeds Rye cover Palmer amaranth response to cover crops. Macon County, GA. 2009.

28. Staple + Reflex + Direx PRE Roundup WMax + Parrlay POST Direx + MSMA Layby Weeds Palmer amaranth response to deep tillage and cover crops. Macon County, GA. 2009. Deep tillage Rye cover crop

29. GR Palmer amaranth influence on cotton lint yield (lb/A) in the Roundup system.* 592 c 690 b Weeds *RR System: Diuron + Reflex + Staple fb Roundup + Parrlay fb Direx + MSMA Inversion + rye Deep inversion 790 a Rye 480 d

30. Dryland Conservation Tillage Prowl + Reflex PRE Roundup + Dual POST Diuron + MSMA PD Prowl + Reflex PRE Ignite + Dual POST Diuron + MSMA PD

31. Applications must be timely with Ignite

32. GR Palmer amaranth control by tillage, cover crop residue, and herbicides. 2009 & 2010. At harvest.* 99 a Weeds *Ignite System: Diuron + Reflex + Staple fb Ignite + Parrlay fb Direx + MSMA Inversion + rye Deep inversion 99 a Rye % 94 b

33. 680 bc 710 ab Weeds *Ignite System: Diuron + Reflex + Staple fb Ignite + Parrlay fb Direx + MSMA Inversion + rye Deep inversion 770 a Rye % 625 c GR Palmer amaranth influence on cotton lint yield in the Ignite system. 2009 & 2010.*

34. 1. Strip tillage into weeds 2. Strip tillage into rye. 3. Strip tillage into rye/deep turning. ON FARM STUDIES Tillage/Cover Crop Options

35. Influencing Palmer Emergence (On farm study, TN) Weeds Rye (large) Deep Turn + Rye 101 10 sq m 45 10 sq m 44 10 sq m

36. Influencing Palmer Emergence (On farm 10 acre study, Macon Co. Georgia) Weeds Rye (large) Deep Turn + Rye Gram. + Direx BD; Prowl + Reflex PRE; RU + Dual POST; Direx + MSMA layby 8242 plants/A 4371 plants/A 446 plants/A

37. No Deep TillageDeep Turn No Herbicide Treatment Number of Palmer Amaranth Plants During Early Season. Macon Co., Georgia 2008.*

38. Influence of burial depth on Palmer amaranth emergence Keeley et al. (1987) reported 36-44% emergence at 0-1”, 7% at 2”, and 2% at 3”.

40. Palmer amaranth seed germination as affected by length of burial

41. Palmer amaranth seed germination as affected by depth of burial

42. 1.Work together! 2.Integrated programs are required to control GR Palmer amaranth in cotton. 3.Deep turning, rye cover, and deep turing + rye will greatly improve control. 4.Incentives to assist in grower adoption of heavy residue. 5.Find more funds to expand NRCS Pilot Program. SUSTAINING COTTON PRODUCTION

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