Weed Management for “Newer” Peanut Counties

1. Weed Management for “Newer” Peanut Counties Dr. Eric P. Prostko Extension Weed Specialist Dept. of Crop & Soil Sciences University of Georgia Tifton April 2004

2. Some things to think about…. • know your weeds • rotational crops • field by field treatments?? • weed competition

3. Weed Competition • 100% weed control is not practical • 1st 4-6 weeks most important • later emerging weeds usually do not cause yield losses (harvest problems) • all weeds are not created equal • generally, grass weeds more competitive than broadleaf weeds

4. Peanut yield losses (%) caused by various weeds at a density of 1 plant/meter of crop row. Source: Thomas et al., 2004, Weed Technology 18:119-123

5. PPI/PRE Sonalan Prowl/Pendimax Dual Magnum Frontier/Outlook Pursuit Strongarm Valor Zorial POST Gramoxone Max Basagran Ultra Blazer Cadre Classic Poast Pursuit Select/Arrow Storm 2,4-DB The Peanut Weed Control Toolbox16 active ingredients

6. The foundation of weed management in peanuts is the yellow/DNA herbicides! • Sonalan, Prowl, Pendimax , Prowl H2O • inexpensive • Texas panicum • Florida pusley • must be incorporated by tillage or irrigation

7. Herbicide Incorporation • type of equipment • number of passes • soil condition • too wet • reduce soil movement • clods • increase in volatility • too dry • reduced adsorption • increased soil flow

8. Herbicide Incorporation

9. Herbicide Incorporation or Equally as effective Center-pivot irrigation is $2-7/A cheaper!

10. Strongarm or Valor • soil-applied • broadleaf weed • both weak on sicklepod • crop injury • rotation restrictions • price/A

11. Strongarm vs. Valor

12. Avoid Valor Injury • read entire label!! • calibrate sprayer • plant at least 1.5” deep • apply immediately after planting • rainfall at-cracking will cause injury • clean sprayer before treating cotton

13. Valor Clean-Up Procedures • tank vs. hose issue • polyurethane vs. rubber • anti-drip systems with diaphragms • flush hoses after use • release pressure • delay spraying for 20-30 seconds

14. Valor Rotation Restrictions

15. Strongarm Rotational Restrictions

16. Consider Using Paraquat • less than $2.00/A • if not using Valor or Strongarm • if beggarweed, sicklepod and t. panicum are main problems • apply early • tank-mixes with Basagran, Storm, 2,4-D, Dual

17. Gramoxone Max 10 ozs/A + Storm (1.5 pt/A) Gramoxone Max 8 ozs/A 1 DAT

18. Consider Using Cadre • controls most weeds except ragweed, croton, bristly starbur • Is it worth the rotational crop risk??

19. Cadre Rotational Restrictions

20. When is the best time to use Cadre? • following an “at-crack” application of paraquat or • following a PRE application of Valor or Strongarm

21. If you cannot use Cadre…... • weed control costs will probably be higher • purple nutsedge will not be controlled • Dual Magnum ($10-14/A) but not as effective. • Older herbicides (Basagran, Blazer, Storm) effective but have some weaknesses

22. Enemies of POST Herbicides • dry weather • big weeds

23. Get the most from your Posts! • can’t do much about the weather but • can greatly influence application * calibration * timing * adjuvants * nozzle selection * spray volume * antagonism

24. Optimum Timing of POST Applications definitely No way!!! probably

25. Weed control programs for $355/ton peanuts?(approximate costs/A)

26. Program 1(15 GAP, not including application)

27. Program 2(15 GAP, not including application) * weed resistance potential increased with this program

28. Program 3(15 GAP, not including application)

29. Program 4(15 GAP, not including application)

30. What herbicides do the top “older” peanut growers use? • 2003 Peanut Achievement Club • 16 Farms • average farm size • 454 acres • average yield • 5141 lbs/A • Top 5 herbicides used • Sonalan = 94% • Cadre = 81% • Gramoxone Max = 56% • 2,4-DB = 50% • Valor, Basagran = 37%