Slide Presentation
TITLE
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Managing Tropical Spiderwort With Sequential Dual Applications During 2005
AUTHOR
T. Flanders,
A.S. Culpepper
, W. Duffle, and A.C. York
University of Georgia and NC State
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TABLE OF CONTENTS
Managing Tropical Spiderwort With Sequential Dual Applications During 2005
Tropical Spiderwort in Georgia
Tropical Spiderwort
Tropical Spiderwort County Map
Why Does Tropical Spiderwort Continue to Spread Through Georgia?
In Georgia, 1105 plants per meter square emerged after early June.
August 1 emergence after controlling 10 days earlier
Why Does Tropical Spiderwort Continue to Spread Through Georgia?
Spiderwort Response to Roundup
Why Does Tropical Spiderwort Continue to Spread Through Georgia?
Estimated Glyphosate-Resistant Planted Acres.
The Benefits from Reduced Tillage Currently Outweigh the Troubles of Tropical Spiderwort
Objectives
Materials and Methods
Application Information
Exp 1: Most effective use of Dual
Dual PRE not labeled on Georgia Soils
Tropical Spiderwort Control at Late-Season. Grady County,
Control 17 Days After Layby
Tropical Spiderwort Size at Time of Layby Application
Control 17 Days After Layby
Control 17 Days After Treatment
RR Visual Cotton Response to Herbicide Treatments 4 d
Exp 2: Most Effective Layby Option
Percent Tropical Spiderwort Control at 9 d after Layby
Percent Tropical Spiderwort Control at Harvest
Percent Tropical Spiderwort Control at Harvest
Summary
Summary
Questions?
SLIDE CONTENTS
Managing Tropical Spiderwort With Sequential Dual Applications During 2005 T. Flanders, A. S. Culpepper, W. Duffie, and A. C. York Univ. of Georgia and N. C. State
Tropical Spiderwort in Georgia 1999 2004 2004 map confirmed by the GA Dept of Ag
Blue = 2004 sites confirmed Black = 2005 sites confirmed
Why Does Tropical Spiderwort Continue to Spread Through Georgia? Emergence pattern
In Georgia, 1105 plants per meter square emerged after early June. Webster, 2004
August 1 emergence after controlling 10 days earlier
Why Does Tropical Spiderwort Continue to Spread Through Georgia? Emergence pattern Lack of residual herbicides
Spiderwort Response to Roundup* *Pictures 15 d after treatment. No plants died from any treatment. Six inch at time of application.
Why Does Tropical Spiderwort Continue to Spread Through Georgia? Emergence pattern Lack of residual herbicides Lack of tillage
Estimated Glyphosate-Resistant Planted Acres. % Acres
The Benefits from Reduced Tillage Currently Outweigh the Troubles of Tropical Spiderwort (at least for the short term)!
Objectives Determine the most effective application rates and timings for Dual Magnum Determine the most effective layby treatment
Materials and Methods Cairo * DP 555 BRR Cotton 2004 and 2005 Planted early May RCB design Four rows by 25 feet Four replications
Application Information Treatments applied at 15 GPA and 3 MPH Tropical spiderwort 1 to 5 inches, avg. 2 to 3 inch 225 per sq. yard Weed control visually estimated throughout season
Exp 1: Most Effective Use of Dual* 4-5 leaf** 12 leaf directed RU RU RU + Dual 16 oz RU RU RU + Dual 16 oz RU + Dual 8 oz RU + Dual 8 oz RU + Dual 12 oz RU + Dual 12 oz RU + Dual 16 oz RU + Dual 16 oz *Prowl PRE applied over trial area; RU = WeatherMax 22 oz/A. Dual = Dual Magnum.
Dual Magnum PRE Dual PRE not labeled on Georgia Soils
Tropical Spiderwort Control at Late-Season. Grady County, Averaged over 2004 and 2005.* *Prowl PRE over trial area.
RU EPOT fb RU Layby Control 17 Days After Layby. Non-treated Control
Tropical Spiderwort Size at Time of Layby Application Roundup Roundup + Dual
RU + Dual EPOT fb RU Layby Control 17 Days After Layby. RU EPOT fb RU + Dual Layby
RU + Dual 8 oz Sequentially RU + Dual 12 oz Sequentially Control 17 Days After Treatment.
RR Visual Cotton Response to Herbicide Treatments 4 d, Avg over 2004 and 2005.* *Prowl PRE over trial area.
Exp 2: Most Effective Layby Option* Factorial of RU RU + Aim (1.5 oz) RU + Valor (1 oz) MSMA + Direx (2 pt) MSMA + Valor (2 oz) *Prowl PRE, Roundup + Dual Magnum 12 oz EPOT; RU = WeatherMax 22 oz/A; MSMA = 2 lb ai/A. No Dual Magnum Dual Magnum 16 oz/A
Percent Tropical Spiderwort Control at 9 d after Layby. Avg. over 2004 and 2005* *Prowl PRE followed by Roundup + Dual Mag (12 oz) EPOST.
Percent Tropical Spiderwort Control at at Harvest. Avg. over 2004 and 2005* *Prowl PRE followed by Roundup + Dual Mag (12 oz) EPOST.
Percent Tropical Spiderwort Control at at Harvest. Avg. over 2004 and 2005* *Prowl PRE followed by Roundup + Dual Mag (12 oz) EPOST.
Summary Sequential applications of Dual Magnum are more effective than single applications. Control by sequential applications tended to be greater with Dual Magnum rates of 12 to 16 oz. Layby applications of Roundup or MSMA plus Valor or Direx as well as Roundup plus Aim offer growers effective burndown of emerged plants at layby
Summary Dual Magnum will be needed with layby applications in heavily infested fields. Current labels are prohibitive for mixing Dual Magnum with several of these options. Programs will be costly and if it don’t rain it don’t work. If it rains too much, the Dual Magnum may last less than 3 weeks.
QUESTIONS?