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2014 Soybean Weed Control Update
Eric P. Prostko
Professor and Extension Weed Specialist
University of Georgia
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PowerPoint - 16.4 MB
PDF - 5.8 MB
TABLE OF CONTENTS
2014 Soybean Weed Control Update
Soybean Weed Control Tips
Narrow Rows and Weed Control - Soybeans
For Growers in Peanut/Cotton Rotations Who Want to Protect Valor and Reflex
Envive Rates/Crop Injury
Soybean Injury Caused by Envive 41.3WG @ 3.5 oz/A 10 DAP
LL-Soybean and Weed Response to Envive SB-02-12
Weed Control in LL Soybeans 2013
Yellow Nutsedge Control in Soybeans
Do early applications of Cobra increase soybean yields?
2014 Pest Control Handbook Additions
Weed Control in Soybeans with Zidua - 2012
GR-Palmer Control in Soybeans with Fierce - 2012
Enlist Herbicide Tolerant Soybean
Enlist Soybeans - 2012
Dicamba-Tolerant (DT) Soybeans
Weed Control in Soybeans with Engenia - 2013
2,4-D and Dicamba Tolerant Soybeans
Volume Median Diameter (VMD)
2,4-D/Dicamba Soybeans- Understanding spray droplet size will be very important!
On the Next Horizon
2014 Soybean Weed Control Update Eric P. Prostko Professor and Extension Weed Specialist Dept. Crop & Soil Sciences
Start clean! 2 residual herbicides Timely POST applications (<3” weeds) narrow row spacing (if you can) Soybean Weed Control Tips
Narrow Rows and Weed Control - Soybeans “A review of row spacing experiments in which an initial weed management practice had been accomplished revealed that in 64% of the cases (72 of 113 site-years), less late-season weed density and/or biomass, or greater late-season weed control, was achieved in narrow- compared to wide-row soybean production systems.” Bradley, K. W. 2006. A review of the effects of row spacing on weed management in corn and soybean. Online. Crop Management doi:10.1094/CM-2006-0227-02-RV.
Just thinking??? Fierce or Valor or Envive or Valor XLT (PRE) followed by Reflex (POST) = great pigweed control but not great ……. Resistance Management PPO followed by PPO Not great in cotton and peanut rotations relying on Valor and Reflex Might be OK in corn/soybean rotation when no PPO is used in corn
For Growers in Peanut/Cotton Rotations Who Want to Protect Valor and Reflex RR Soybeans Warrant or Dual Magnum fb Glyphosate + Reflex (Flexstar GT) Tricor or Boundary or Canopy or Authority MTZ (metribuzin herbicides) fb Glyphosate + Reflex (Flexstar GT) LL Soybeans Warrant or Dual Magnum fb Liberty + Reflex Reflex or Valor fb Liberty + Warrant or Dual Magnum No metribuzin on LL varieties Herbicide Resistance?
Envive Rates/Crop Injury Dupont 41.3% WG Classic – 9.2% Valor – 29.2% Harmony – 2.9% Rate range of 2.5-4.0 oz/A I prefer 2.5 oz/A Similar injury situation occurs with Valor XLT Most likely cause is Classic
Soybean Injury Caused by Envive 41.3WG @ 3.5 oz/A 10 DAP NTC Envive SB-21-11
LL-Soybean and Weed Response to Envive SB-02-12 (June 12) NTC Envive 41.3DG @ 3.5 oz/A (PRE) Liberty 2.34SL @ 22 oz/A (POST)
Liberty-Link® Soybeans Liberty 2.34SL @ 22-36 oz/A VE-R1 2 applications (65 oz/A/year total) Tank-mixes with POST grass herbicides may reduce grass control Assure (10-21%); Fusilade (8-12%); Poast (25-41%); Select (4-22%) Residuals still needed Variety performance? Getting better **Best Results 15 GPA, medium droplet size, small weeds, 9 am - 6 pm
Weed Control in LL Soybeans 2013 SB-23-13 July 17 NTC Dual Magnum @ 16 oz/A (PRE) Liberty @ 29 oz/A (MPOST) Reflex @ 16 oz/A (MPOST)
Yellow Nutsedge Control in Soybeans How competitive? 2.2-13 plants/m2 = 9-34% yield loss Nelson and Smoot (2010) Weed Technol. 24:39-43 Herbicides Dual Magnum – PRE + Classic or Basagran – POST Classic = 3-4” tall Basagran = up to 8”, 2 applications
Do early applications of Cobra increase soybean yields? Nebraska (2013) Decreases in yield were observed by destroying apical meristem by both clipping at V2 and applications of Cobra Arkansas V3 stage 21% increase in yield (2011) No difference in yield (2012) Iowa (2011) V2.5 stage No positive effect Multi-State (MN, WI, MI, IA, KS, IL, IN, AR, KY) 2012 V4 stage No positive effect from Cobra alone Increased yield with SOYA + Cobra (+8.9%) but not different from SOYA alone.
2014 Pest Control Handbook Additions (pyroxasulfone) (Valor + Zidua)
Zidua 85WG Pyroxasulfone Residual control of annual grasses and certain broadleaf weeds including pigweed (beggarweed?) Same MOA as Dual or Warrant but used at lower rates Use rate: 1-2 oz/A (~$6.50/oz)
Weed Control in Soybeans with Zidua - 2012 SB-01-12 August 13 83 DAP NTC Zidua 85WG @ 2 oz/A – PRE Abundit 4SL @ 32 oz/A – POST AMS Xtra @ 2.5% v/v - POST
Fierce 76WDG Valor (33.5%) + Pyroxasulfone (42.5%) preplant or preemergence 3 oz/A on coarse soils (Valor @ 2 oz/A + Pyrox @ 1.5 oz/A) March 2013
GR-Palmer Control in Soybeans with Fierce – 2012 SB-10-12 August 9 78 DAP NTC Fierce 76WG @ 3 oz/A - PRE Roundup WM 5.5SL @ 22 oz/A – POST (June 20)
Future Technologies 2,4-D resistance Dicamba resistance
Enlist™ Herbicide Tolerant Soybean tolerance to 2,4-D + glyphosate + glufosinate (Liberty) Colex-D™ technology 2,4-D choline lower volatility lower drift potential enhanced handling/mixing characteristics reduced odor 1 Burndown/PRE application + 2 POST applications (R2 stage) Enlist™ Duo DMA-Glyphosate (1.71 lb ae/gal) + 2,4-D choline (1.63 lb ae/gal) 3.5 pt/A 2015 Product Launch (MG 3.8) Pioneer License 2,4-D choline
Enlist Soybeans - 2012 NTC Valor SX 51WG @ 2 oz/A – PRE (May 4) Enlist Duo (GF-2726) @ 56 oz/A – MPOST (June 1) N-PAK AMS @ 2.5% v/v - MPOST (June 1) SB-09-12 Planted May 3 Photo: June 29
Dicamba-Tolerant (DT) Soybeans Monsanto/BASF Roundup Ready 2 Xtend (Monsanto) XtendiMax Reduced volatility dicamba Roundup Xtend Reduced volatility dicamba + glyphosate Engenia™ (BASF) Reduced volatility formulation of dicamba Banvel = dicamba-DMA Clarity = dicamba-DGA Engenia = dicamba–BAPMA PRE or POST RESIDUAL STILL NEEDED!!!!!!!!!!!!!!!!!!!!!!! 2015-2016? Engenia™
Weed Control in Soybeans with Engenia - 2013 Newsome July 30, 2013 39 Days after POST NTC Zidua @ 2 oz/A (PRE) Engenia @ 12.8 oz/A (POST) Roundup PowerMax @ 28 oz/A (POST) Induce @ 0.25% v/v (POST)
2,4-D and Dicamba Tolerant Soybeans Still need a residual! Still need to be timely (3-4” tall weeds)! Will also need Ignite! Not on Xtend beans though! Must significantly improve in the areas of drift and sprayer contamination management
Volume Median Diameter (VMD) value where 50% of the total volume or mass of liquid sprayed is made up of droplets larger than this value, and 50% is made up of droplets smaller than this value. Dv0.5 Measured in microns
2,4-D/Dicamba Soybeans Understanding spray droplet size will be very important!
On the Next Horizon HPPD resistant soybeans Bayer/MS Technologies “Balance” beans Glyphosate + isoxaflutole 2015????? Syngenta + Bayer “MGI” beans Mesotrione (Callisto) Glufosinate (Liberty) Isoxaflutole (Balance) 2015-2020????