2011 Corn Weed 2011 Corn Weed Control Update Control Update Eric - PowerPoint PPT Presentation

2011 Corn Weed 2011 Corn Weed Control Update Control Update Eric P. Prostko Extension Weed Specialist Dept. Crop & Soil Sciences

Topics for Discussion Topics for Discussion t Atrazine Review t RR Corn Control (replant) t Steadfast Q t LL Corn t Palmer Amaranth t New (er) Products

Atrazine Evaluation Update Atrazine Evaluation Update t October 2009 – EPA calls for New Evaluation t Scientific Advisory Panel (SAP) Meetings è Human Health Effects è February, April, September (2010) è At September meeting, results of NCI Agricultural Health Study were not available è Additional SAP meeting sometime in 2011 è Then, SAP review of atrazine effects on amphibians and aquatic ecosystems t Registration review in 2013?

2007, 2008, 2010 M acon County Triazine-Resistance Survey

Macon County Resistance Survey Macon County Resistance Survey Location Atrazine Glyphosate Staple Cadre 1 Y ? ? ? 3 Y ? ? ? 4 Y ? ? ? 5 Y ? ? ? 6 Y ? ? ? 7 N ? ? ? 8 Y ? ? ? 9 N ? ? ? 10 N ? ? ? 11 N ? ? ? 12 N ? ? ? 13 N ? ? ? 14 Y ? ? ? 15 Y ? ? ? 16 N ? ? ? 17 Y ? ? ? 18 N ? ? ? 19 Y ? ? ? 20 Y ? ? ? 21 N Y Y N 22 23 Y Y Y Y 24 Y N Y Y 25 N Y Y N

Macon County Resistance Survey Macon County Resistance Survey Location Atrazine Glyphosate Staple Cadre 26 27 28 29 30 Y Y Y Y 31 N Y Y Y 32 33 N ? N Y 34 Y Y Y N 35 36 N Y Y Y 37 38 39 40 41 N Y N N 42 43

RR Corn Control (Pioneer 33M57) RR Corn Control (Pioneer 33M57) 7 DAT - - 2010 2010 7 DAT SelectMax 0.97EC @ 6 oz/A NTC Gramoxone Inteon 2SL @ 40 oz/A Induce @ 0.25% v/v Atrazine 4L @ 32 oz/A AMS X-TRA @ 2.5% v/v Agridex @ 1% v/v

RR Corn Control (Pioneer 33M57) RR Corn Control (Pioneer 33M57) 40 DAT - -2010 2010 40 DAT NTC SelectMax 0.97EC @ 6 oz/A Gramoxone Inteon 2SL @ 40 oz/A Induce @ 0.25% v/v Atrazine 4L @ 32 oz/A (123 Bu/A) AMS X-TRA @ 2.5% v/v Agridex @ 1% v/v (0 Bu/A) (27 Bu/A)

Q Products Q Products Steadfast Q 37.7DG Steadfast Q 37.7DG Accent 75DG Accent 75DG 1.5 oz/A 1.5 oz/A 0.67 oz/A 0.67 oz/A Accent (0.024 lb ai/A) i.e. 0.5 oz/A Accent (0.024 lb ai/A) i.e. 0.5 oz/A (0.031 lb ai/A) (0.031 lb ai/A) Resolve (0.012 lb ai/A) Resolve (0.012 lb ai/A) Isoxadifen (safener) Isoxadifen (safener)

Accent vs. Steadfast Q - - 2010 2010 Accent vs. Steadfast Q Accent 75 WDG @ 0.67 oz/A NTC Accent 75 WDG @ 0.67 oz/A Steadfast Q 37.7WDG @ Steadfast Q 37.7WDG @ 1.5 oz/A 1.5 oz/A NTC Atrazine 4L @ 48 oz/A Atrazine 4L @ 48 oz/A Atrazine 4L @ 48 oz/A Atrazine 4L @ 48 oz/A Primary @ 1% v/v Primary @ 1% v/v Primary @ 1% v/v Primary @ 1% v/v CN-04-10 June 4 53 DAT

What about Liberty- -Link Corn? Link Corn? What about Liberty (different mode of action compared to glyphosate) (different mode of action compared to glyphosate) t Glufosinate è Ignite 2.34SL (22 oz/A) è 44 oz/A year (total) t up to 24” or V7 (OT) or 24”-36” (drops) t Tank-mix with atrazine t good on morningglory, Texas millet, sicklepod, small Palmer (3” or less)

Weed Control in LL- -Field Corn Field Corn - - 2010 2010 Weed Control in LL Macon County - - 47 DAP 47 DAP Macon County Ignite 280 2.34SL @ 22 oz/A NTC Atrazine 4L @ 1 qt/A N-Pak AMS @ 2.5% v/v Applied 24 DAP

Concerns About LL Crops Concerns About LL Crops t Residual Important è 1 may not be enough t Abuse of Ignite è LL cotton, corn, soybeans è may jeopardize future technologies (DHT, Dicamba) t Current Resistant Weed s è Goosegrass (Malaysia)

GR- Amaranthus sp. Amaranthus palmeri Illinois Missouri Kentucky N Carolina Tennessee Arkansas Amaranthus rudis S Carolina 4 Counties in Mid-South Mississippi Georgia m a A l a b a Louisiana Larry Steckel (UT) September 2010

Palmer Amaranth Control Tactics – – Field Corn Field Corn Palmer Amaranth Control Tactics t Start Clean!!!!! t Irrigation t Tillage t Extreme Cover Crops t Residual Herbicides è More than 1 t Timely POST’s t Post-Harvest

Palmer Control in Field Corn Palmer Control in Field Corn t Residuals è Atrazine è Dual Magnum/Generics è Micro-Tech t RR corn è Glyphosate + atrazine + Prowl è Expert è Halex GT ( + atrazine?) t LL Corn è Ignite + atrazine + Prowl(?) t Conventional è Steadfast Q + atrazine (ALS?) è Laudis + atrazine è Callisto + atrazine

Roundup + Atrazine + Prowl - - 2010 2010 Roundup + Atrazine + Prowl NTC RUWM 5.5SL @ 22 oz/A CN-04-10 Atrazine 4L @ 1.5 qt/A June 4 Prowl H 2 0 @ 1 qt/A 53 DAT

Halex GT - - 2010 2010 Halex GT Halex GT 4.39SC @ 3.6 pt/A NTC 80/20 @ 0.25% v/v AMS X-TRA @ 2.5% v/v CN-14-10 June 3, 2010 51 DAT

Post- -Harvest AMAPA Problems Harvest AMAPA Problems Post t Decreasing daylight hastens flower and seed production è Flowering (3-4 weeks) è Seed production (2-3 weeks) è Some germination at 41 0 F (8%) t Control Options è Mowing è Tillage è Herbicides • paraquat + 2,4-D amine or dicamba • Residuals i.e Dual Magnum? t When can we stop worrying about seed production? Keeley et al. 1987. Weed Science 35:199-204 Steckel et al., 2004. Weed Science 52:217-221

When can we stop worrying about Palmer seed production? Year First Frost Date FFD-35 (FFD) 2005 Dec 20 Nov 15 2006 Nov 20 Oct 16 2007 Nov 8 Oct 4 2008 Nov 19 Oct 15 2009 Dec 21 Nov 16 2010 Dec 2 Oct 27 Source: UGA Automated Environmental Monitoring Network Tifton Campus Conference Center

Other Herbicides We Might Need to More Other Herbicides We Might Need to More Seriously Consider in GA Field Corn? Seriously Consider in GA Field Corn?

Callisto 4SC Callisto 4SC t Syngenta t POST t 3 oz/A + COC + UAN or AMS ($12-13/A) t Up to 30” tall or 8-leaf corn t Palmer amaranth up to 5” t Tank-mix with atrazine è Callisto Xtra t also good on horsenettle t Interaction with OP’s t Weak on PANTE and CASOB t Good option for atrazine, ALS and GR-Palmer t Unique mode of action è “Bleacher”

Callisto Callisto 7 DAT 7 DAT Callisto 4SC @ 4 oz/A NTC Agrioil @ 1% v/v AMS @ 1.28 lb/A CN-01-09

Laudis 3.5SC Laudis 3.5SC t Bayer t Tembotrione + isoxadifen (safener) t “Bleacher” t POST è 3 oz/A è Emergence to V8 stage t Requires use of MSO and nitrogen t Good for pigweed management t Also has crabgrass and BL signalgrass listed on label t No OP interaction t Is it as good as Accent/Steadfast Q on Texas millet?

Laudis – – 2010 2010 Laudis 51 DAT 51 DAT Laudis 3.5SC @ 3 oz/A NTC Atrazine 4L @ 16 oz/A MSO @ 1% v/v CN-14-10 AMS @ 2.5% v/v

Status 56WG Status 56WG t BASF t dicamba + diflufenzopyr + isoxadifen t “Super” Banvel + safener t POST t 5-10 oz/A ($2.20/oz) t broadleaf weed control only t no residual

GR- GR -Palmer Amaranth Control in Field Corn with Status Palmer Amaranth Control in Field Corn with Status (70 DAT) Status 56WG @ 5 oz/A NTC NIS @ 0.25% v/v AMS @ 3 lb/A EPOST (21 DAP) CN-01-08

On the Horizon On the Horizon t DHT Corn è DowAgroScience Herbicide Tolerance è Enhanced tolerance to 2,4-D and “fops” è Stacked with glyphosate è 2013? t Herbicides è Zidua (pyroxasulfone) - BASF è Capreno (Laudis + thiencarbazone + isoxadifen) - Bayer

DHT Corn DHT Corn

DHT Systems– – 2010 2010 DHT Systems Palmer Amaranth (GR) + Crabgrass NTC Durango DMA 4SL @ 16 oz/A Weedar 64 3.8SL @ 17 oz/A CN-10-10 N-PAK AMS @ 2.5% v/v 9 DAT

Weed Control in Georgia Field Corn with Zidua Weed Control in Georgia Field Corn with Applied PRE (Photo @ 32 DAT) Applied PRE (Photo @ 32 DAT) Zidua 85WG @ 1.67 oz/A NTC Atrazine 4L @ 1.5 qt/A (0.09 lb ai/A) CN-02-08

Capreno (3 oz/A) + COC (1% v/v) + 28% UAN Capreno (3 oz/A) + COC (1% v/v) + 28% UAN (2.5% v/v) (2.5% v/v) NTC EPOST (14 DAP) MPOST (23 DAP) CN-13-10 May 13 43 DAP

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