Managing glyphosateresistant Palmer amaranth in Liberty Link cotton'

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Managing glyphosate-resistant Palmer amaranth in
Liberty Link cotton.

• A.W. MacRae1, A.S. Culpepper1,
• and J.M. Kichler2
• 1Crop and Soil Sciences Department
• University of Georgia, Tifton, GA
• 2Southwest District - CES
• University of Georgia

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Glyphosate-resistant Palmer amaranth

• Glyphosate resistant Palmer amaranth has been
  found in 4 counties in Georgia.
• There was 144,330 acres planted in these counties
  in 2005 (Georgia/Publications/County_Estimates/200
  6/GaCotton.pdf)
• Roundup Ready technology is used on 98 of
  Georgias acreage

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WMax 22 oz EPOST, 0.5 WMax 22 oz MPOST, 3 WMax
22 oz LPD, 10
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Objective

• Determine the efficacy of Liberty Link cotton
  weed management systems for control of
  glyphosate-resistant Palmer amaranth

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Experimental Design

• Randomized complete block design with 4
  replications.
• Cultivar used FM 988 LLBR
• 4 row plots
• Center two rows used for data collection
• Data collected
• Weed efficacy
• Cotton yield

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Non-treated
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Treatments 1st Set

• PRE Prowl H2O (2 pt/A)
• POST Ignite 280 (23 oz/A), 3 to 4-lf cotton
• PRE
• POST Ignite 280 (29 oz/A), 3 to 4-lf cotton
• POST Ignite 280 (29 oz/A), 11-lf cotton
• PRE
• POST Ignite 280 (29 oz/A), 4 to 5-lf cotton
• POST Ignite 280 (29 oz/A), 11-lf cotton

Layby MSMA (2.7 pt/A) Direx (2 pt/A) NIS
(0.25 v/v)
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Palmer amaranth control (30 DBH)
Layby MSMA Direx NIS
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Ignite (23 oz) at 5 inch Ignite (23 oz) at 5
inch Direx MSMA PD
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Ignite (23 oz) at 2 inch Ignite (23 oz) at 2
inch Direx MSMA PD
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Prowl PRE Ignite (23 oz) at 2 inch Direx MSMA PD
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Seed Cotton Yield
Layby MSMA Direx NIS
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Treatments 2nd Set

• PRE Prowl H2O (2 pt/A)
• POST Ignite 280 (29 oz/A), 3 to 4-lf cotton
• PRE Prowl H2O (2 pt/A)
• POST Ignite 280 (23 oz/A) Staple LX
• (1.7 oz/A), 3 to 4-lf cotton
• PRE Prowl H2O (2 pt/A)
• POST Ignite 280 (23 oz/A) Dual Magnum
• (1 pt/A), 3 to 4-lf cotton
• 4) PRE Prowl H2O (2 pt/A)
• POST Ignite 280 (23 oz/A), 3 to 4-lf cotton
• POST Ignite 280 (23 oz/A), 11-lf cotton

Layby MSMA (2.7 pt/A) Direx (2 pt/A) NIS
(0.25 v/v)
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Palmer amaranth control (30 DBH)
PRE Prowl H2O POST Ignite applied to 3 to
4-lf cotton Layby MSMA Direx NIS
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Prowl PRE Ignite (23 oz) at 2 inch Direx MSMA PD
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Prowl PRE Ignite (29 oz) at 2 inch Direx MSMA PD
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Prowl PRE Ignite (23 oz) Staple at 2 inch Direx
MSMA PD
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Prowl PRE Ignite (23 oz) Dual Mag. at 2
inch Direx MSMA PD
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Prowl PRE Ignite (23 oz) at 2 inch Ignite (23 oz)
at 2 inch Direx MSMA PD
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Seed Cotton Yield
PRE Prowl H2O POST Ignite applied to 3 to
4-lf cotton Layby MSMA Direx NIS
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Treatments 3rd Set

• PRE Prowl H2O (2 pt/A) Reflex (1 pt/A)
• POST Ignite 280 (23 oz/A), 3 to 4-lf cotton
• PRE Prowl H2O (2 pt/A) Reflex (1 pt/A)
• POST Ignite 280 (23 oz/A) Staple LX
• (1.7 oz/A), 3 to 4-lf cotton
• PRE Prowl H2O (2 pt/A) Reflex (1 pt/A)
• POST Ignite 280 (23 oz/A) Dual Magnum
• (1 pt/A), 3 to 4-lf cotton

Layby MSMA (2.7 pt/A) Direx (2 pt/A) NIS
(0.25 v/v)
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Palmer amaranth control (30 DBH)
PRE Prowl H2O POST Ignite applied to 3 to
4-lf cotton Layby MSMA Direx NIS
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Prowl PRE Ignite (23 oz) at 2 inch Direx MSMA PD
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Prowl Reflex PRE Ignite (23 oz) at 2 inch Direx
MSMA PD
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Prowl Reflex PRE Ignite (23 oz) Staple at 2
inch Direx MSMA PD
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Seed Cotton Yield
PRE Prowl H2O POST Ignite applied to 3 to
4-lf cotton Layby MSMA Direx NIS
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Treatments 4th Set

• PRE Prowl H2O (2 pt/A) Cotoran (2.5 pt/A)
• POST Ignite 280 (23 oz/A), 3 to 4-lf cotton
• PRE Prowl H2O (2 pt/A) Cotoran (2.5 pt/A)
• POST Ignite 280 (23 oz/A) Staple LX
• (1.7 oz/A), 3 to 4-lf cotton
• PRE Prowl H2O (2 pt/A) Cotoran (2.5 pt/A)
• POST Ignite 280 (23 oz/A) Dual Magnum
• (1 pt/A), 3 to 4-lf cotton

Layby MSMA (2.7 pt/A) Direx (2 pt/A) NIS
(0.25 v/v)
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Palmer amaranth control (30 DBH)
PRE Prowl H2O POST Ignite applied to 3 to
4-lf cotton Layby MSMA Direx NIS
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Prowl PRE Ignite (23 oz) at 2 inch Direx MSMA PD
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Prowl Cotoran PRE Ignite (23 oz) at 2
inch Direx MSMA PD
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Seed Cotton Yield
PRE Prowl H2O POST Ignite applied to 3 to
4-lf cotton Layby MSMA Direx NIS
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Summary

• 1) Timing of Ignite 280 application is more
  important that rate of Ignite 280 used.
• 2) Palmer amaranth must not be greater than 2
  inches in height to achieve optimum control.
• 3) Applying Prowl H2O PRE produced 220 lbs more
  seed cotton than a second application of Ignite
  280 with no PRE.

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Summary

• 4) The addition of Dual Magnum POST or a second
  shot of Ignite 280 provided 11-12 greater Palmer
  amaranth control (30 DBH) and 350-380 lbs more
  seed cotton.
• 5) The addition of Reflex or Cotoran PRE provided
  18-22 greater Palmer amaranth control (30 DBH)
  and 290-320 lbs more seed cotton.

Based on PRE Prowl H2O POST Ignite 280 at 2
in Palmer, 3 to 4-lf cotton LAYBY MSMA DIREX
NIS
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Summary

• 6) The addition of Dual Magnum or Staple POST to
  applications of Prowl H2O Cotoran or Reflex PRE
  provided no benefit.

Based on PRE Prowl H2O POST Ignite 280 at 2
in Palmer, 3 to 4-lf cotton LAYBY MSMA DIREX
NIS
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Conclusions

• 1) Ignite 280 must be applied timely.
• 2) Preemergence
• a) Yellow herbicide Reflex
• b) Yellow herbicide Cotoran
• c) Yellow herbicide Direx
• 3) Postemergence
• a) Ignite Dual Magnum
• b) Ignite 2 applications
• 4) Layby - MSMA Direx, Valor, Layby Pro, or
  Suprend

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Prowl PRE, Roundup POST Twice
Prowl PRE, Ignite POST Twice
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2006 Georgia OVT
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• Support for this project and my PAYCHECK has been
  provided by
• Georgia Cotton Commission
• Cotton Incorporated
• BASF
• Bayer
• Dupont
• Monsanto
• Syngenta
• Valent

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Questions?
Andrew W. MacRae Post Doctoral Research
Associate Department of Crop and Soil
Sciences University of Georgia, Tifton, GA
UGA Weed Science Website www.gaweed.com