1. Dr. Eric P. Prostko Extension Weed Specialist Dept. Crop & Soil Sciences University of Georgia December 2004 2005 Weed Control Update (Peanut, Field Corn, Soybeans, Sunflowers)

2. Peanuts t Spartan t Cobra t newer metolachlor formulations t Valor Issues t others issues

3. Spartan in Peanut t Labeled in 2004 3not in FL t 4F formulation t 4.8 to 8.0 ozs/A t soil-applied t broadleaf weed control t nutsedge t cotton rotation concerns t crop injury on lighter soils t PPO inhibitor

4. Spartan Rotation Restrictions

5. Spartan Injury

6. Cobra in Peanut t Labeled in Fall 2004 t postemergence 36 leaf peanut 390 day PHI t 12.5 ozs/A t broadleaf weed control t a hotter Blazer t tank-mixes with Basagran, Cadre, Pursuit, Select, 2,4- DB t PPO inhibitor

7. Metolachlor Mysteries? t 9 formulations in marketplace t new metolachlors (88% s + 12% r) 3Dual Magnum, Dual II Magnum (Syngenta) 3Cinch (DuPont) t old metolachlors (50% s + 50% r) 3Stalwart, Stalwart C (Sipcam) 3Me-Too-Lachlor, Me-Too-Lachlor II (Drexel) 3 Parallel PCS, Parallel (Makhteshim-Agan)

8. Metolachlor Prices *only labeled for use in field corn and popcorn

9. Tropical Spiderwort

10. Tropical Spiderwort Response to Dual Magnum and Stalwart, Grady Co., 2004 - I Applied PRE at 1 pt/A. *

11. Tropical Spiderwort Response to Dual Magnum and Stalwart, Grady Co., 2004 - II Applied POST at 1 pt/A with glyphosate to 3” tall COMBE. *

12. Valor Issues: Is that hose clean? Tank/Line RinsateLine in Glyphosate

13. Valor and Sprayer Cleanup

14. Which plot had AMS? Which plot had AMS? (Both had Cadre at 1.44 ozs/A + Agrioil @ 1% v/v applied 24 DAP) PE-08-04 July 1,2004 28 DAT

15. Which plot had AMS? PE-08-04 August 3, 2004 54 DAT 403404

16. Field Corn t Option vs. Accent t RR corn issues 3glyphosate timings

17. Field Corn Option vs. Accent t POST grass control t except crabgrass t OP/SU interaction t roughly same cost/A t 2004 Option was less effective than Accent

18. Texas Panicum Control - I Accent vs Option - 2004 CN-03-04 (Ponder Farm) Applied 22 DAP PANTE = 1”, 3-4 leaf a a abc bcd b cc d

19. Texas Panicum Control - II Accent vs Option - 2004 CN-04-04 (Attapulgus) Applied 21 DAP PANTE = 1-2”, 2-4 leaf ab b a b a b a b

20. Texas Panicum Control - III Accent vs Option - 2004 CN-06-04 (Attapulgus) Applied 21 DAP PANTE = 1-2”, 3-4 leaf ab abc a ab a bcd

21. Texas Panicum Control (104 DAT) - II Accent vs Option - 2004 CN-04-04 (Attapulgus) Applied 21 DAP PANTE = 1-2”, 2-4 leaf Untreated Accent @ 0.67 ozs/A Agrioil @ 1% v/v Option @ 1.5 ozs/A MSO @ 1.25% v/v AMS @ 3 lbs/A

22. Conventional or RR Systems?

23. Are the RR hybrids any good? CN-07-04 b b a aa a a

24. Use Rates for Glyphosate in RR Corn

25. Soybeans t Nutsedge control in RR beans t RR cotton in RR soybeans t Mn tank-mixes t Sequence t tropical spiderwort t glyphosate timings

26. Nutsedge Management in RR Soybeans t split applications of glyphosate 3better on purple than yellow t tank-mix with Classic 3controls yellow suppresses purple t tank-mix with Pursuit 3better on purple than yellow 3 rotations/cost

27. Controlling RR Cotton in RR Soybeans t Canopy - PRE 3metribuzin + chlorimuron 38 ozs/A t POST glyphosate tank- mixes 3Resource (4 ozs/A) 3Reflex (12 ozs/A) 3Classic (0.33 ozs/A) t need PRE fb POST to be most effective

28. Glyphosate/Manganese Tank-Mixes t research from VA has shown that Mn will reduce weed control when tank-mixed with glyphosate 3 9 to 38% reductions depending upon species t Mn not a problem with Blazer, Classic, Pursuit, or Basagran. Sources: Bailey et al., 2002 (Weed Technology 16:792-799) and Heckman et al., 1999 (Journal of Production Agriculture 12:445-448)

29. Sequence for Weed Control in RR Soybeans t label in October 2004 t mixture of glyphosate -K + Dual Magnum t 2.5 -3.0 pts/A 3$/15-18/A 30.70 ae + 0.94 ai (2.5 pts) 30.84 ae + 1.13 ai (3.0 pts) t prior to 3rd trifoliate t tropical spiderwort?

30. Tropical Spiderwort Management in RR Soybeans t Use Dual Magnum or generic PRE in known fields t tank-mix Pursuit or Classic with glyphosate t Extreme 2.17SC @ 3 pts/A = glyphosate (0.75 lb ai/A) + Pursuit (0.063 lb ai/A)

31. To Prevent Yield Loss in RR Soybeans  control weeds by 4-5 weeks after planting or  control weeds before they reach 6-9” in height or  control weeds before the V3 stage Source: Purdue University Extension Weed Science Group, 2004 (4.7 million acres of RR soybeans planted)

32. Sunflowers t Spartan t PPI or PRE t 4F @ 3-3.75 ozs/A t only soil applied broadleaf herbicide registered

33. University of Georgia Extension Weed Science (gaweed.com)