1. Peanut Weed Management Issues - 2006 Eric P. Prostko Extension Weed Specialist Department of Crop & Soil Sciences The University of Georgia Tifton GA Peanut Farm Show - 2006

2. Topics for Discussion What’s new for 2006? Herbicide resistance –ALS –Glyphosate Tropical spiderwort Reduced tillage systems

3. What is new for 2006?

4. A new formulation of paraquat 2 lbs ai/gallon Safer formulation – alginate – alerting agent (decaying grass odor) – purgative – emetic – green dye

5. G-MaxG-Inteon Lbs ai/gal3.02.0 Normal Rates (peanuts) 5.4-8.0 ozs/A8.0-12.0 ozs/A Maximum/year (in-crop peanuts) 10.8 ozs/a16.0 ozs/A vs.

6. Cadre 70DG vs. Cadre 2AS Cadre 70DGCadre 2AS Normal use rate 1.44 oz/A4.0 oz/A Reduced rate (not supported by BASF) 1.00 oz/A2.8 oz/A

7. What about ALS-resistant pigweed?

8. Causes of Herbicide Failures weed size** moisture temperature humidity rate nozzle type GPA calibration bad luck herbicide resistance All possible reasons for poor performance should be investigated before considering the possibility of resistance!!!

9. Herbicide Resistant Weeds Selection Pressure Source: J.L. Gunsolus. Herbicide Resistant Weeds. 1998. North Central Region Extension Publication 468.

10. Commonly Used ALS Herbicides Accent Ally Beacon Cadre Classic Envoke Exceed Express Finesse FirstRate Harmony Extra Osprey Peak Permit/Sandea Pursuit Python Scepter Staple Strongarm All have the same mode of action!!!!!!!

11. ALS-Resistant pigweed has been identified in at least 4 counties!

12. 2005 ALS-Resistant Pigweed Survey 61 samples, 21 counties

13. If ALS-Resistance is Suspected Prowl or Sonalan –What about DNA- resistance? Cautious use of …… –Classic –Cadre –Pursuit –Strongarm Consider adding….. –Valor –Dual Magnum –Outlook Don’t be afraid of Gramoxone Ultra Blazer or Cobra –Tank-mix with Cadre

14. Do you need Gramoxone? PE-07-05 July 18, 2005 (69 DAP) Ponder Farm Untreated (374 lbs/A) Gramoxone Max + Pledge + NIS @ (15 DAP) Fb Cadre + COC @ (28 DAP) (2170 lbs/A) Cadre + COC @ (28 DAP) (1212 lbs/A)

15. Glyphosate Resistance Around the World (8 species) rigid ryegrass (1996) goosegrass (1997) horseweed (2000) Italian ryegrass (2001) hairy fleabane (2003) buckhorn plantain (2003) common ragweed (2004) Palmer amaranth (2005) –In Central Georgia * Can be found in US

16. WeatherMax 66 oz/A

17. Worried About Hard to Kill Weeds? 67% of 600 Indiana growers are not overly concerned that some weeds are shrugging off Roundup as farmers expect chemical companies to develop new herbicides for weeds that do not respond to Roundup. Purdue University, Nov 29, 2005, Herbicide-defiant weeds causing anxious moments

18. Timeliness the Key!!!!

19. 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)

21. TSW in Georgia Current Known Distribution * confirmed in 29 counties by GA Dept. of Ag and UGA in 2004 (blue) * identified in 4 more counties in 2005 (black)

22. Tropical Spiderwort Control Conventional vs. strip-tilllage Twin rows vs. single rows Prowl or Sonalan (PPI or PRE) Gramoxone Inteon (12 oz/A) + Basagran (8 oz/A) + Dual Magnum (11-16 oz/A) Followed by Cadre (1.44 oz/A) or Strongarm (0.45 oz/A) + Dual Magnum (11-16 oz/A) Cost/A = ~$44-51

23. Tillage Impact on Tropical Spiderwort Cotton & Peanut Rotation Dr. B. Brecke University of Florida 2005 Conventional = Moldboard plow (12”), disk-harrow, field cultivator

24. What have we learned about using yellow herbicides in strip-tillage systems??? (2004-2005) Rate –1.5 lb ai/A > 1.00 lb ai/A Formulation – Prowl EC = Prowl H 2 0 Timing –PRE > 4 WBP > 8 WBP Method –Spray > Fertilizer Fertilizer Rate –500 lbs/A > 250 lbs/A

25. How do we manage the yellow herbicides in strip-tillage systems? Use Prowl/Pendimax Increase rate to at least 3 pts/A Apply broadcast Split application –1 pt/A – Burndown –2 pt/A – at-planting Gramoxone at-plant Will still need a POST grass herbicide

26. Strip-Tillage and Grass Weeds

27. www.gaweed.com