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Evaluation of K4 for Weed Control in Sandland Sugarcane. C. Rainbolt, L. Baucum, and I. Ezenwa. 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
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Evaluation of K4 for Weed Control in Sandland Sugarcane C. Rainbolt, L. Baucum, and I. Ezenwa
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”
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
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
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
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%
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
Control K4 at 3 lbs/A 26 DAPOST
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
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
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
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
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
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
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
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
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
Conclusions • Crop injury tends to be more severe in plant cane and larger cane (>4” 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
Acknowledgements • Many thanks to: • Paige Farms • Duda • USSC • ALICO • DuPont