Evaluation of K4 for Weed Control in Sandland Sugarcane

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Evaluation of K4 for Weed Control in Sandland
Sugarcane

• C. Rainbolt, L. Baucum, and I. Ezenwa

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Introduction

• K4 herbicide is a commercial mixture of
  hexazinone and diuron
• Preemergence herbicide with some post activity
• Registered for use in Florida sugarcane in 2005
• From the label Do not use DuPont K-4 on
  gravelly or rocky soils, thinly covered subsoils,
  or coarse-textured soils (sands to sandy loams)
  with less than 1 organic matter

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Situation and Objective

• Previous research with K4 in FL has focused on
  muck soils
• Based on chemical and soil properties, ideal use
  rates will likely differ
• Objective determine optimum use patterns and
  rates for weed control and crop safety on
  sandland sugarcane

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Methods

• 5 trials were established on sandland cane in
  2005
• Trial 1- Duda, CP84-1198 ratoon
• Trial 2- Paige Farms, CP84-1198 ratoon
• Trial 3- ALICO, CP84-1198 plant
• Trials 4 5- USSC, CL88-4730 ratoon
• Plots were 4 rows wide x 40 ft long

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Treatments
Treatment Rate/A Timing
K4 NIS 1 lb 0.25 PRE and POST
K4 NIS 2 lb 0.25 PRE and POST
K4 NIS 3 lb 0.25 PRE and POST
K4 Surfix 3 lb 0.25 PRE and POST
Aatrex NIS 4 lb 0.25 PRE and POST
Prowl H2O NIS 7 pt 0.25 PRE and POST
Valor NIS 4 oz 0.25 PRE and POST
Valor NIS 6 oz 0.25 PRE and POST
Aatrex Prowl H2O NIS 4 lb 0.25 PRE and POST
K4 Unison 3 lb 2 pt POST
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Treatment Rate Application Tropical crabgrass
kg/ha timing
hexazinone diuron 0.15 0.53 PRE
hexazinone diuron 0.3 1.05 PRE
hexazinone diuron 0.45 1.6 PRE
atrazine 4.5 PRE
pendimethalin 3.7 PRE
flumioxazin 0.14 PRE
flumioxazin 0.21 PRE
atrazine pendimethalin 4.5 3.7 PRE
hexazinone diuron 0.15 0.53 EPOST
hexazinone diuron 0.3 1.05 EPOST
hexazinone diuron 0.45 1.6 EPOST
atrazine 4.5 EPOST
pendimethalin 3.7 EPOST
flumioxazin 0.14 EPOST
flumioxazin 0.21 EPOST
atrazine pendimethalin 4.5 3.7 EPOST
untreated control
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Duda Moore Haven

• Application information
• Preemergence December 29, 2005
• Crop stage emerging
• Weeds emerging
• Postemergence February 1, 2006
• Crop stage 3-4 inch TVD
• Weeds common ragweed, purple nutsedge, spiny
  amaranth, dayflower, torpedograss, and
  bermudagrass

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Duda Moore HavenPRE Results

• 14 days after PRE treatment (DAPRE), crop injury
  was 3 to 5 with all Valor and K4 treatments
• 34 DAPRE control of tropical crabgrass was 84 to
  94 with all PRE treatments except Valor
• 34 DAPRE all treatments controlled spiny amaranth
  83 to 95

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Duda Moore Haven Results- 26 days after post
treatments (DAPO)

• Control of tropical crabgrass was 85 to 95 with
  K4 and Prowl H2O Aatrex applied PRE
• Treatments with K4 at 2 or 3 lbs/A POST
  controlled tropical crabgrass 95 or better
• Crop injury was 20 or higher with Valor applied
  POST and 5 to 15 with K4 applied POST
• Control of spiny amaranth was 90 or greater with
  all treatments except K4 at 1 lb/A PRE and Prowl
  H2O alone

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Control
K4 at 3 lbs/A 26 DAPOST
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Paige Farms

• Application information
• Preemergence January 31, 2006
• Crop stage emerging
• Weeds emerging
• Postemergence March 1, 2006
• Crop stage 3-4 inch TVD
• Weeds fall panicum, American black nightshade,
  and common ragweed

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Paige FarmsPRE Results 27 DAPRE

• Control of fall panicum was 60, 78, and 90 with
  K4 1, 2, and 3 lbs/A, respectively
• Control of fall panicum with Prowl H2O was 79
• Crop injury with K4 ranged from 0 to 10 and
  increased with higher rates
• American black nightshade and common ragweed
  control were not significantly different between
  treatments

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Paige Farms Results- 41 DAPO

• Control of fall panicum with PRE treatments was
  highest (85) with K4 at 2 and 3 lbs/A
• Fall panicum control with POST treatments was
  highest with treatments containing K4 at 2 and 3
  lbs/A
• Crop injury averaged 10 with treatments
  containing 3 lbs of K4 and 5 with 2 lbs of K4

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Paige Farms 41 DAPO
Control
POST- K4 at 3 lb/A Surfix
POST- Aatrex at 4 lbs/A
PRE- K4 at 3 lbs/A NIS
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ALICO

• Application information
• Preemergence March 1, 2006
• Crop stage emerging
• Weeds emerging
• Postemergence March 27, 2006
• Crop stage 4-5 inch TVD
• Weeds southern crabgrass and common purslane

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ALICOResults 26 DAPRE

• Control of southern crabgrass was highest (88 to
  89) with K4 at 2 and 3 lbs/A and Prowl H2O
  Aatrex
• Common purslane control was 80 or better with
  all treatments except Valor
• Crop injury averaged 5 to 9 with K4 at 2 and 3
  lbs/A and Valor

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ALICO Results- 15 DAPO

• Control of southern crabgrass was still above 80
  with PRE applications of K4 at 2 and 3 lbs/A and
  Prowl H2O Aatrex
• POST treatments were too late for successful
  southern crabgrass control (best control was 65
  with K4 at 3 lbs/A alone and Unison
• Crop injury was 11 to 20 with all K4 treatments

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USSC

• Application information
• Preemergence April 14, 2006
• Crop stage emerging
• Weeds emerging
• Postemergence May 1, 2006
• Crop stage 4-5 inch TVD
• Weeds fall panicum, purple nutsedge, spiny
  amaranth

• Two trials were conducted in adjacent fields
• PRE herbicide performance is negatively impacted
  by dry soils
• One trial was irrigated with 1 inch within 1
  week of herbicide application

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USSC Results

• Data collection and analysis not completed in
  time for presentation
• A report including a full analysis of results
  from all locations will follow in late summer

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Conclusions

• Crop injury tends to be more severe in plant cane
  and larger cane (gt4 to TVD)
• Crop injury may be more severe in warmer
  conditions when cane is growing faster
• Results indicate that 2-3 lbs applied PRE or very
  early POST provides weed control similar or
  better than standard treatments

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Acknowledgements

• Many thanks to
• Paige Farms
• Duda
• USSC
• ALICO
• DuPont