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TITLE    (click title to view slides)
2003: Managing Tropical Spiderwort in Roundup Ready Cotton

AUTHOR
T. Flanders, University of Georgia
A. S. Culpepper, University of Georgia
A. C. York, N. C. State University
B. Brecke, University of Florida

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TABLE OF CONTENTS
  1. Managing Tropical Spiderwort in Roundup Ready Cotton
  2. Tropical Spiderwort, Facts
  3. Tropical Spiderwort, Map
  4. Tropical Spiderwort, Asiatic dayflower, Spreading dayflower
  5. Picture - Underground flowers
  6. Picture - Underground fruiting structures
  7. Tropical Spiderwort in Georgia
  8. Spiderwort's rank as Georgia's most troublesome weeds in cotton
  9. Spiderwort response to Roundup UltraMax
  10. Tropical spiderwort infestation
  11. Objectives
  12. Materials and Methods
  13. Application Information
  14. PRE Treatments: GA Locations Only
  15. Tropical Spiderwort Response to PRE herbicides. 3 WAT. 2 GA Loc. 2003.
  16. Early POT Treatments: GA, NC, FL
  17. Cotton Response to Dual or Staple Plus WeatherMax
  18. Percent Tropical Spiderwort Control. 2 Weeks after early POT. 2003.
  19. Early POT Treatments in GA
  20. Percent Tropical Spiderwort Control. 2 Weeks After Early POT. 2003.
  21. Layby Treatments. GA and NC, 2003.
  22. Cotton Response to Directing Command or Spartan plus WeatherMax. Georgia, 2003.
  23. Command directed at Layby in GA. 5 DAT
  24. Tropical Spiderwort Control at 2 Week After Layby.
  25. In Georgia, 1700 plants per meter square emerged.
  26. Late-Season Spiderwort Control Pooled Over 2 GA and 1 NC locations.
  27. Most Consistently Effective Spiderwort Systems at Harvest. Pooled over 3 locations.
  28. Summary
  29. Questions?



SLIDE CONTENTS
  1. Managing Tropical Spiderwort in Roundup Ready Cotton T. Flanders, A. S. Culpepper, A. C. York, and B. Brecke Univ. of Georgia, N. C. State, and Univ. of Florida
  2. Native to Asia and Africa 1928: Introduced to US Mid-1930’s: Common throughout Florida 1983: Federally Noxious Weed TROPICAL SPIDERWORT Commelina benghalensis T. M. Webster and APHIS
  4. Asiatic dayflower Spreading dayflower Tropical spiderwort
  5. Underground flowers 2002 Arlene Mendoza North Carolina State University
  6. above ground below ground seed seed tropical spiderwort below ground fruiting structures
  7. Tropical Spiderwort in Georgia Red = severe Orange = moderate Green = light Yellow = exist Gray = not found 1999 2002
  8. Spiderworts rank as Georgia’s Most troublesome weeds in cotton 1999: not ranked 2001: ninth 2002: number 1 2003: number 1, 2, and 3
  9. Spiderwort response to Roundup UltraMax* *Pictures 15 d after treatment. No plants died from any treatment. Six inch at time of application.
  10. Tropical spiderwort infestation, Cairo, GA, 2001.
  11. Objectives Evaluate PRE, early POST, and layby treatments for the control of tropical spiderwort Determine the most effective systems approach for managing spiderwort.
  12. Materials and Methods Cultivar: various RR cultivars Planted: April 30 – May 9 Plot size: four rows by 20 to 30 feet Design: RCB Reps: 3 rep Fl, 4 reps GA and NC
  13. Application Information Treatments applied at 15 to 20 GPA Treatments applied at 3 to 4 MPH Tropical spiderwort 1 to 4 inches, avg. 2 to 3 inch 175 per sq. m in GA, 7 in FL, and 2 in NC Weed control visually estimated throughout season
  14. PRE Treatments: GA Locations Only Prowl (1 qt) Prowl + Cotoran (1 qt) Prowl + Cotoran + Zorial (1.25 lb)
  15. Tropical Spiderwort Response to PRE herbicides. 3 WAT. 2 GA Loc. 2003. Percent Control a b c
  16. Early POT Treatments: GA, NC, FL Roundup WeatherMax (22 oz) RU + Dual Magnum (1.33 pt) RU + Staple (0.6 oz)
  17. Roundup UltraMax Cotton Response to Dual or Staple Plus WeatherMax. Georgia, 2003. WeatherMax + Dual Magnum WeatherMax + Staple NC: < 5% GA1: 10-12% at 4 d, <2% at 12 d GA2: 12-14% at 4 d, <2% at 12 d NC: < 5% GA1: 17% at 4 d, <2% at 14 d GA2: 34% at 4 d, <5% at 14 d
  18. *Prowl applied PRE. **Statistical comparison within column only. Percent Tropical Spiderwort Control. 2 Weeks after early POT. 2003.*
  19. Between May 28 and June 4, 175 plants per square meter emerged. By June 4, only 30% of our population had emerged. Early POT Treatments in GA Applied on May 24.
  20. Percent Tropical Spiderwort Control. 2 Weeks After Early POT. 2003.* *Prowl applied PRE. Prowl + Cotoran applied PRE. **Statistical comparison within column only.
  21. Layby Treatments. GA and NC, 2003. Roundup WeatherMax (22 oz) RU + Direx (1.5 pt) RU + Command (1.33 pt) RU + Valor (1 oz) RU + Valor (2 oz) RU + Spartan (5.5 to 6.7 oz)
  22. Cotton Response to Directing Command or Spartan plus WeatherMax. Georgia, 2003. Injury less than 8% with all treatments in NC, less than 12% at GA 1, but between 15 and 22% at GA 2. Spartan injury was stem and leaf necrosis, Command injury was..
  23. Command directed at Layby in GA. 5 DAT.
  24. Tropical Spiderwort Control at 2 Week After Layby. >89% in NC with all treatments >90% in GA1 except RU alone >80% in GA2 except RU and RU + Direx alone
  25. In Georgia, 1700 plants per meter square emerged. 65% of these emerged after the layby was applied.
  26. *Statistical differences at P = 0.05. Late-Season Spiderwort Control Pooled Over 2 GA and 1 NC locations.*
  27. Most Consistently Effective Spiderwort Systems at Harvest. Pooled over 3 locations.* *The only treatments that controlled spiderwort greater then 85% at each location.
  28. Summary 1. Cotoran PRE provided fair control for up to 3 weeks. 2. Mixing Dual with RU early POST improved control 17 to 32% in GA, NC, or FL at 2 WAT due to residual control. 3. Roundup + Command or Spartan were the most effective layby materials due to residual control. 4. No labeled treatment provided greater than 85% control at GA1, GA2, and NC.
  29. QUESTIONS?