2011 Glyphosate-Resistant Palmer Amaranth Management in Cotton Culpepper, Steckel, York

Amaranthus rudis Amaranthus palmeri Tennessee Missouri Illinois Mississippi Georgia S Carolina N Carolina Alabama Louisiana Arkansas GR Pigweed in the Mid-south and Southeast Steckel 2010

Managing GR Palmer in Cotton (Southeast and MidSouth)  Weed Control Systems Starting clean At-plant residuals Postemergence options Layby directed and hooded options  Roundup- and Ignite-based program  Building integrated programs Tillage, cover crops, etc

Preplant/PRE herbicides for Palmer amaranth in Roundup Ready Cotton in SE Preplant PRE Valor Direx

Controlling 5 inch Glyphosate-Resistant Palmer amaranth at Burndown. Macon Co., GA 2008.* 0 c 87 b 94 a 58 b RoundupFirestorm 2 pt 70 b Firestorm + 2,4-D (1.5 pt) Firestorm + Clarity (8 oz) Firestorm + Diuron (1.8 pt) *COC included with all Firestorm treatments

Palmer control at planting, burndown applied 17 d earlier. Macon Co., GA b Valor preplant Direx preplant 99 a

2 GR Weeds in the Same Field Steckel 2010

Burndown Programs for GR Horseweed/Palmer Programs: Glyphosate + Clarity (1/2 pt)** + residual herbicide Glyphosate + 2,4-D (2 pt)** + residual herbicide SE residual: Direx or Valor MS residual: Valor

Preplant/PRE herbicides for Palmer amaranth in Roundup Ready Cotton in SE Preplant PRE Valor Prowl + diuron + Staple DirexReflex + Staple Reflex + Cotoran Reflex + diuron Reflex + Prowl Prowl + Cotoran Prowl + diuron *Paraquat included with PRE except conventional till!

Palmer amaranth control by PRE herbicides; 40 days* Cotoran Prowl Valor** Direx Caparol Reflex % control * Average of 5 locations; 2 in GA, 3 in NC. No other herbicides included. ** Applied same time as the PRE herbicides. Staple (ALS susceptible)

GR Weed Management in Cotton Cotoran/Caparol or Reflex on coarse soils 30 to 21 DBPPre Emergence Dicamba + glyphosate or Gramoxone Inteon +/- Valor Near Planting Burndown Reflex apply 14 DBP and ½” of rain

Controlling GR Palmer amaranth in RR cotton SE and MS. POST1 1-lf cotton POST lf cotton Layby RU + Staple (emerged pigweed) RU + Dual or Warrant RU + Dual or Warrant Diuron Suprend Layby Pro + MSMA

Concept of Overlapping Residuals Critical herbicide concentration

Concept of Overlapping Residuals Critical herbicide concentration

Concept of Overlapping Residuals Critical herbicide concentration

Early topical applications with residual needed before Palmer emerges in RR cotton!! Prowl + Reflex PRE, Roundup + Dual Magnum POST 1, Roundup + Warrant POST 2, Direx + MSMA layby POST 1 = 25 days after PREPOST 1 = 17 days after PRE

Hooded Spray or Layby Rig Diuron + MSMA + COC Suprend + MSMA + COC Layby Pro + MSMA + COC Gramoxone + diuron + COC (+ Valor) (still have to direct to row)

Monsanto’s Roundup Ready Cotton Performance Roundup Ready Flex Cotton (Up to $20) Valor 2 oz OR Reflex 1 pt = ($4.00) Cotoran, Cotton Pro, Caparol, diuron 2 pt = ($3.00)* Warrant 3 pt or Dual Magnum 1 pt = ($4.50 or $3.00) Gramoxone Inteon 2 pt = ($1.00) *Will pay on 2 applications

Dryland Conservation Tillage Prowl + Reflex PRE Roundup + Dual POST Diuron + MSMA PD Prowl + Reflex PRE Ignite + Dual POST Diuron + MSMA PD

Palmer response to Ignite WATER VOLUME AND NOZZLE TYPE IS CRITICAL MUST KILL IT WITH THE FIRST APPLICATION

Timing is critical!! 3 to 4 inches for consistent Palmer control. Weed Management in Glufosinate-Tolerant Cotton This is not a 4-inch pigweed!

32 oz/A Gly 4 fb 29 oz/A Ignite on 12” Palmer

7 days after IGN application 20 days after IGN application Palmer amaranth must be small (3 to 4 inches) if consistently controlled by Ignite Whitaker

Controlling GR Palmer amaranth in LL conventional DRYLAND cotton. PREPLANT and PRE POST1 1-lf cotton POST lf cotton Layby 1. diuron + Reflex 2. Cotoran + Reflex 3. Prowl + Reflex 4. Diuron + Staple 5. Cotoran + Staple 6. Diuron PRE 7. Cotoran PRE 8. Treflan PPI Ignite 29 oz + Dual Mag. Ignite 29 oz diuron + MSMA

Phytogen Widestrike Cotton 1.Confers tolerance to Ignite 2.Tolerance not complete; injury will occur and yield loss can occur if you don’t know what you are doing. 3.According to EPA, Ignite can be applied to widestrike cotton. 4.However, grower is liable as neither Bayer, Dow, nor any University recommends or warrant the use of Ignite on Widestrike cotton

Phytogen Widestrike Cotton (treated with Ignite) 2004: 1 plot (researchers playing) 2005: 0.25 acres (research) 2006: 16 acres (research) 2007: <20,000 acres 2008: ~40,000 acres 2009: ~225,000 acres 2010: >750,000 acres

LL WRF Agronomic performanceImprovingProven Grass controlMay need helpCan apply Roundup Morningglory controlExcellentExcellent with Ignite GR horseweed controlGoodGood with Ignite Can apply RoundupNO!Yes Tolerance to IgniteExcellent Acceptable (when follow recommendations) Weed management in LL vs WRF cotton

375 WideStrike Cotton Tolerance to Multiple Applications of Ignite Pounds Lint Cotton Culpepper, York and Steckel 2010 a a a b

375 WideStrike Cotton Tolerance to Multiple Applications of Ignite Pounds Lint Cotton a a b No Ignite Ignite 2 lf and 7 lf Ignite 2 lf, 7 lf, bloom

375 WideStrike Cotton Tolerance to Multiple Applications of Ignite Pounds Lint Cotton a a b No Ignite Ignite 2 lf and 7 lf Ignite 2 lf, 7 lf, bloom

2 lf Photo 5 d after 2 lf application

Photo 5 d after bloom + 2 wk application

Can not survive with herbicides alone any longer

Staple + Reflex + Direx PRE Roundup WMax + Parrlay POST Direx + MSMA Layby What percent Palmer amaranth control?

Developing Integrated Programs

York 2010 Hand Weeding 2010: GA: Herbicide input: $90 million 2010: TN: Herbicide input: $35 million

York 2010 Hand Weeding GA: 92% of growers handweeding 53% of the 2010 crop = $16 million TN: growers handweeding 20% of crop = $3 million

TREFLAN/PROWL PPIPRE

5 % acres *Average of Macon, Taylor, Sumpter, Schley, and Dooly counties Herbicide Incorp. 0 Impact of GR Palmer amaranth in Georgia counties with severe infestations.*

Tillage in Cotton During 2010 %PPI tillageGA Counties # Worth, Pualski, Tift, Berrien, Echols, Turner, Brooks, Pierce, Marion, Grady, Emanual, Montgomery, Atkins, Coffee, Lowndes, Dooly, Wilcox, Thomas, Crisp, Schley, Webster, Colquitt Bullock, Jefferson, Treutlen, Wheeler, Daugherty Effingham, Telfair, Tattnall, Dodge, Toombs, Jeff Davis, Bleckly, Early, Lanier, Irwin, Lee, Macon 13 >50Jenkins, Johnson, Washington, Screven, Wayne, Laurens, Randolf, Decatur, Seminole, Miller, Taylor Ben Hill 12

Most Palmer amaranth emerges from top inch

No Deep TillageDeep Turn No Herbicide Treatment Number of Palmer Amaranth Plants During Early Season. Macon Co., Georgia 2008.*

GR Palmer amaranth control by tillage and cover crop residue * 0 b 50 a Weeds *No herbicide Deep inversion %

Palmer requires a significant amount of sunlight to emerge!!

>90% control in middles

In the rye, control loss was in the strip

Activating our residual herbicides! Palmer free at planting! Ignite resistance management! PPO resistance management! ALS (and other) chemistry resistant mgmt! Tons of Issues/Challenges

Comments or Questions? 2002: $20/A2010: $63/A