2002 Cotton Production Workshop Tifton, GA Culpepper and York

Topics for Discussion Burndown for conservation tillage Liberty Link Technology Roundup Ready Flex Early-season weed competition Touchdown + Dual Magnum CGA 362622 = Envoke; Suprend Aim (directed treatments Valor (directed treatments) Roundup resistance concerns Tropical spiderwort Morningglory Palmer amaranth Glyphosate formulations Topics for Discussion

Cotton Burndown

Cotton Burndown Focus: cutleaf eveningprimrose Put 2,4-D out in Feb/March followed by glyphosate or paraquat near planting 2. Apply glyphosate or paraquat + 2,4-D near planting (be aware of plant back interval)

Cotton Burndown Put 2,4-D out in Feb/March followed by glyphosate or paraquat near planting a) better weed coverage, smaller weeds b) very flexible at planting c) no plant back issues d) tank hopefully cleaned out by now e) two trips are necessary

Cotton Burndown Apply glyphosate or paraquat + 2,4-D near planting (be aware of plant back interval) plant back restrictions weed coverage questionable tank cleanout more of an issue single application

If you want use 2,4-D then *Beware of plant back restrictions Glyphosate plus Clarity* Or Glyphosate plus Valor* *Beware of plant back restrictions

Relative Response of Cutleaf Eveningprimrose to Glyphosate Tank Mixes.* Harmony Extra Alone Aim Goal Resource Valor Clarity 2,4-D 16 6 13 6 6 12 7 16 # of trials *Estimates based on GA and NC data 30 DAT from 1999 to 2002.

Wheat Response to Glyphosate Applied Alone and in Mixture with Caparol Wheat Response to Glyphosate Applied Alone and in Mixture with Caparol. Ponder Farm, 2001; 16 DAT. Roundup UltraMax (1.6 pt) + 1.5 pt Caparol

Summary - cutleaf eveningprimrose 1. 2,4-D, glyphosate + 2,4-D, paraquat + 2,4-D 2. glyphosate + Valor or Clarity

Percent primrose control by Liberty. Tifton, 2002 Percent primrose control by Liberty. Tifton, 2002. 33 day after treatment.* 93 85 56 20 oz 27 oz 32 oz Liberty *Not an economical option at this time.

Wild Radish

Wild Radish Impact on Cotton Emergence Wild radish Cotton stand residue* reduction 0.5 29 1.0 78 1.5 100 2.0 100 *percent of soil by weight. Jason Norsworthy, Clemson University.

Summary - Wild radish 1. glyphosate + 2,4-D, Harmony Extra paraquat + 2,4-D, Direx, Harmony Extra 2. glyphosate + Valor, Direx 3. glyphosate

Liberty Link Cotton

Liberty Link (2003) Approximately 15 bags per sales rep 2 cultivars: 989 and 966 series, no Bt

Liberty Link (2004) Liberty is expensive…..how will it compete

Liberty Link (2004) – One Possibility Roundup Ready Seed + 2 application of glyphosate equals (approximately) Liberty Link Seed + 2 applications of Liberty (32 oz)

Liberty vs. Roundup* Weed Liberty Roundup Application window + - Eveningprimrose + - Goosegrass - + Large grasses - + Morningglory + - Nutsedge - + Palmer amaranth - + Perennial grasses - + Volunteer peanut + - *Control of many weeds is similar. Assuming proper rates and application.

Pitted Morningglory Response to Liberty and Glyphosate Pitted Morningglory Response to Liberty and Glyphosate. Moultrie, GA, 2001. non-treated Liberty glyphosate (27 oz/A) (0.75 lb ae/A)

non-treated Liberty (27.4 oz/A) LL cotton trial, TyTy, 2001.

Palmer must be small for Liberty

Possible Liberty Link Systems Yellow herbicide at plant, Liberty 1-2 leaf topical, Liberty 6-8 leaf topical, timely directed 2. Yellow plus Cotoran or Staple, Liberty timely 3- 6 leaf,

Roundup Ready Flex Will contain new transformation event Greater gene expression in floral parts Greater tolerance to later overtop applications 2006???

Roundup Ready Flex tolerance study. 2002 Roundup Ready Flex tolerance study. 2002. Mechanically harvested seed cotton yield. lb ae/A* *Applied overtop 3-, 6-, 10-, and 14-leaf. **Not in commercial variety.

Early Season Weed Competition 2 inch weeds 5 inch weeds 8 inch weeds Application Timing

Early Season Competition First 4 to 6 weeks still most important for weeds 2. Approximately 40% of time use PRE or be willing to make 2 topical applications following label recommendations.

Effect of PRE Herbicides on RR Seedcotton Yield.1 No PRE Avg. 10 PRE’s 1460 a 1070 b 1Study in 1998 conducted at Goldsboro, NC.

Trifloxysulfuron-sodium Trifloxysulfuron-sodium is a post-emergence, broad-spectrum, ALS inhibitor herbicide Trifloxysulfuron will be marketed in two brands: Envoke – 75WG trifloxysulfuron Suprend – trifloxysulfuron + prometryn

Envoke New product from Syngenta Fourth quarter EPA work plan Broadleaf and sedge herbicide, do NOT mix with graminicides Short soil residual; limited PRE activity

Envoke vs. Staple* Weed Envoke Staple Application window + Dayflower species ++ Morningglory + Nutsedge ++ Palmer amaranth + Prickly sida ++ Sicklepod ++ Smallflower mg** ++ Tall morningglory ++ *Assuming proper postemergence rates and application. **Absolutely no control by Envoke

Zorial PRE + Envoke 0.0047 LB A/A 14 DAT

Envoke applied under Envoke applied under favorable conditions dry conditions 14 DAT

Smallflower Morningglory Control. 14 DAT. glyphosate Envoke

Mix with Staple or glyphosate: Envoke Mix with Staple or glyphosate: Apparently NO

Where might Syngenta promote the herbicide? Envoke Where might Syngenta promote the herbicide?

Syngenta RR Cotton Herbicide Program plus

Nutsedge Control with Envoke Untreated check Glyphosate + Dual 1- to 2-leaf Envoke 5- to 8-leaf

Injury Issues with Envoke Expect some injury. Usually moderate but occasionally severe. Recovers quickly with no yield loss in most studies across Southeast. Envoke 0.0047 lb/A OT 4-lf Non-treated Control

New cotton herbicide from Syngenta Suprend New cotton herbicide from Syngenta Contains trifloxysulfuron-sodium + prometryn at 1:133 ratio Formulated as 80% WDG Applied postemergence-directed Use rate of 1 to 1.5 lb/acre 1.0 lb Suprend 1.6 pt Caparol 1.5 lb Suprend 2.4 pt Caparol Broadleaf weeds and nutsedge; weak on grasses ~ ~

Syngenta Cotton Herbicide Program + Dual MAGNUM

Touchdown plus Dual Magnum Apply to cotton > 3” but before 5 leaf stage Do not use ANY additive, avoid dew

From glyphosate plus Dual Injury Range From glyphosate plus Dual

Cotton Response to Glyphosate + Dual* heavy dew no dew *Application with dew applied 7 am. Application without dew applied 11 am.

Touchdown plus Dual Magnum Apply to cotton > 3” but before 5 leaf stage Do not use ANY additives, avoid dew Do not mix with staple

Do not apply Dual and Staple within a couple of days of each other glyphosate + Dual glyphosate + Dual + Staple

Touchdown plus Dual Magnum Apply to cotton > 3” but before 5 leaf stage Do not use ANY additives, avoid dew Do not mix with staple Residual weed control of pigweeds, grasses, pusley, and spiderwort

glyphosate @ 4 leaf cotton + Dual Magnum 1 pt/A 1) Dayflower emerged 3 to 7 day after 4 leaf application. Rain 3 d after application. 2) Prowl applied PRE. No layby.

glyphosate @ 4 lf + 1 pt Dual Magnum Attapulgus, 2001 *Irrigated within 48 hrs.

Dual vs. Staple in Glyphosate Topical Mixture* Weed Dual Staple Annual grasses ++ Dayflower species ++ + Florida pusley + Morningglory ++ Nutsedge + Palmer amaranth ++ ++ Sicklepod Cost of treatment ++ *Assuming proper postemergence rates and application.

Do Not Use Dual PRE on Georgia Soils Dual Magnum PRE

Aim Postemergence-directed label claims control of: pigweed species lambsquarters cocklebur morningglory velvetleaf spurred anoda smartweed hemp sesbania common ragweed

Tank mix with glyphosate to improve morningglory control Most Likely Fit for Aim in Cotton Tank mix with glyphosate to improve morningglory control

Large Morningglory Response to Layby Herbicides. 5 DAT. Irwin Co Large Morningglory Response to Layby Herbicides. 5 DAT. Irwin Co., GA, 2001. Roundup UltraMax 1.6 pt + Aim 0.6 oz/A *Trial conducted on farm in Irwin County with Gibbs Wilson.

Most Likely Fit for Aim in Cotton What about tank mixing with other products for morningglory control?

Glyphosate + Aim Glyphosate alone directed applications

Plant terminal response to Aim “running” the stem

Aim Application Timing Treat Aim as a true layby directed herbicide applying when cotton is at least 16 inches tall and the stem is completely woody.

Valor for Layby (2004) 4th quarter 2003 EPA workplan 18 inch cotton or larger, completely “woody” glyphosate plus 1-2 oz per acre MSMA plus 2 oz per acre postemergence control of most weeds residual control of many weeds

Large Morningglory Response to Layby Herbicides. 5 DAT. Irwin Co Large Morningglory Response to Layby Herbicides. 5 DAT. Irwin Co., GA, 2001. Roundup UltraMax 1.6 pt UltraMax 1.6 pt + Valor 1 oz *Trial conducted on farm in Irwin County with Gibbs Wilson.

Valor for Layby (2004) Off-labeled use of this product in 2003 could jeopardize the potential for a 2004 label

Weed Resistance to Glyphosate

Weed Resistance to Glyphosate: Should We Be Concerned?

Weed Resistance to Glyphosate: Should We Be Concerned? ABSOLUTELY!

Known Cases of Resistance to Glyphosate Species Location Goosegrass Malaysia Rigid ryegrass California, Australia, South Africa Italian ryegrass Chile Horseweed Tennessee, Delaware

HORSEWEED

How Can We Deal With Resistance? 1. Take your chances, deal with it if and when it happens Manage to avoid it, or at least delay its development

Practical Things to Help Avoid Resistance 1. Avoid over-reliance on same mode of action a. Rotate modes of action b. Use more than one MOA Tank mixes, sequential applications

Practical Things to Help Avoid Resistance 1. Avoid over-reliance on same mode of action a. Rotate modes of action MOA tables in Extension pubs or online b. Use more than one MOA Tank mixes, sequential applications 2. Integrate non-chemical control, such as cultivation and primary tillage, where practical

Detecting Herbicide Resistance Most control failures NOT due to resistance Eliminate other possible causes first Inadequate herbicide rate Poor/improper application Poor timing of application Unfavorable weather Later weed flushes Antagonism by other pesticides

Indicators of Resistance Performance poor on one species, other species controlled well Product normally controls weed in question Poor control confined to spots in field Some plants of species in question controlled well, others controlled poorly

Year 1 Progression of Herbicide Resistance Year 3 Year 2 Year 4 Year 5

Weed Shifts are a greater issue at this time in Georgia cotton

Tropical spiderwort Asiatic dayflower Spreading dayflower

below ground fruiting structures above ground below ground seed seed

Spiderworts rank as Georgia’s Most troublesome weeds in cotton 1999: not ranked 2001: ninth 2003: number 1

Spiderwort response to Roundup UltraMax* 20 oz 0 oz 30 oz 0 oz 40 oz 0 oz 50 oz 0 oz *Pictures 15 d after treatment. No plants died from any treatment.

37 “systems” evaluated at 2 locations to control tropical spiderwort in 2002. Control at harvest: < 50% control: 49 50 to 80% control: 19 80-90% control: 5 >90% control: 1

Grady Co. 2002

What do we know from 2002? Greater than 85% residual control at 30 days: Command Dual (can not use at plant) Greater than 70% residual control at 30 days: Cotoran Direx* Zorial *Caparol or Cotton-Pro not included in trial.

What do we know from 2002? Postemergence control (<3 inch): 1. Paraquat (Gramoxone, Boa) (>90%) 2. MSMA (2 lb/A) tank mixes (80-90%) 3. Glyphosate + Aim, Direx, Staple (70-85%)

What do we know from 2001-2002? Best system so far: Prowl/Treflan at plant (no effect on spiderwort) Glyphosate + Dual early POST Direx (1 qt) + MSMA (2 lb/A) directed All applications were EXTREMELY timely.

Percent tropical spiderwort control at cotton harvest Percent tropical spiderwort control at cotton harvest. Grady County, 2001-2002. 95 87 78 57 Yellow herbicide at plant; glyphosate + Dual early Post; Direx + MSMA directed

What do we know from 2002? We must get more residual in the program Where do we put the residual We must learn spiderwort emergence pattern If you don’t have the weed; make sure you don’t get it.

Tropical Spiderwort Infestation Red = severe Orange = moderate Green = light Yellow = exist Gray = not found

Morningglory Continues to be Troublesome to Georgia Growers? WHY??????

Morningglory Continues to be Troublesome to Georgia Growers? At plant: Cotoran, Direx, Staple Early Post: Glyphosate, Staple, Staple Plus Directed: MSMA plus Caparol, Cobra, Cotoran, Direx, Staple, glyphosate plus Aim, Caparol, Direx, Harvade, Staple

Morningglory Continues to be Troublesome to Georgia Growers? Timeliness of application (i.e. large at time of application) No residual in the system

Residual Morningglory Control? Cotoran Direx Staple Caparol

Fairly common scene at harvest across the state

Two Possible Issues? Pigweed is to large at time of layby Pigweed comes up after layby

Two Possible Issues? Pigweed is to large at time of layby a) add a preemergence herbicide such a yellow herbicide, Cotoran, Staple b) Add Dual or Staple in at early POST

Two Possible Issues? 2. Pigweed comes up after layby a) use layby option with residual activity such as Direx, Caparol, Prowl

Glyphosate Formulations

Glyphosate Formulations Numerous brands available All registered for burndown, selective applicators, and preharvest Most, but not all, registered for use in RR crops

Registered Uses on Roundup Ready Crops Brand Soybean Corn Cotton Clearout 41 Plus Yes Yes Yes Gly-4 Yes Yes Yes Gly-4 Plus Yes Yes Yes Gly-Flo No Yes No Glyfos Yes Yes Yes Glyfos X-TRA Yes Yes Yes Glyphomax Yes Yes Yes Glyphomax Plus Yes Yes Yes Gly Star Original Yes Yes Yes Gly Star Plus Yes Yes Yes Roundup Original Yes Yes No Roundup UltraMax Yes Yes Yes Roundup WeatherMax Yes Yes Yes Touchdown Yes Yes Yes

Glyphosate Formulations Numerous brands available Three basic formulations

O O O O O O CH3 O O HO-C-CH2-N-CH2-P-OH H3NO-C-CH2-N-CH2-P-ONH3 Glyphosate acid O O H3NO-C-CH2-N-CH2-P-ONH3 Glyphosate diammonium salt = = = = O O CH3 HO-C-CH2-N-CH2-P-OH2N-CH CH3 Glyphosate isopropylamne salt O O HO-C-CH2-N-CH2-P-OK Glyphosate potassium salt = = = =

Glyphosate Formulations Some brands are “loaded”, some require surfactant; AMS and drift control agent can be added to any Formulations and concentrations vary; only way to compare use rates is on the basis of acid equivalence

Basic Glyphosate Formulations Formulation Brand lb salt/gal lb ae/gal diammonium Touchdown 3.57 3.0 salt potassium Roundup 5.5 4.5 salt WeatherMax isopropylamine All except 4.0 3.0 salt the above 5.0 3.7 5.4 4.0

Formulation lb salt/gal lb ae/gal Comparative rates IPA salt 4.0 3.0 0.375 lb ae = 16 fl oz 0.563 lb ae = 24 fl oz 0.750 lb ae = 32 fl oz IPA salt 5.0 3.7 0.375 lb ae = 13.0 fl oz 0.563 lb ae = 19.5 fl oz 0.750 lb ae = 26.0 fl oz DA salt 3.57 3.0 0.375 lb ae = 16 fl oz K salt 5.5 4.5 0.375 lb ae = 10.7 fl oz 0.563 lb ae = 16.0 fl oz 0.750 lb ae = 21.3 fl oz

So, which brand of glyphosate should you use?

So, which brand of glyphosate should you use? 1. Crop and weeds apparently don’t care

So, which brand of glyphosate should you use? 1. Crop and weeds apparently don’t care 2. Pricing is important

So, which brand of glyphosate should you use? 1. Crop and weeds apparently don’t care 2. Pricing is important 3. Also consider service and guarantees

So, which brand of glyphosate should you use? 1. Crop and weeds apparently don’t care 2. Pricing is important 3. Also consider service and guarantees 4. Should you consider future developments in technology?

Roundup WeatherMax 1. Replacing UltraMax 2. Potassium salt 5.5 lb salt/gal; 4.5 lb ae/gal 3. 30-min rainfree warranty 4. Claim better activity under marginal conditions 5. Better bulk handling characteristics

2002 Cotton Production Workshop Tifton, GA Culpepper and York