2001 Cotton Production Workshop

Waiting until spring to control weeds glyphosate or paraquat PLUS Aim, Caparol, Clarity, Direx, Harmony Extra, Goal, Resource, Valor, and 2,4-D

Glyphosate Tank Mixes on Cutleaf Eveningprimrose. GA & NC data Gly alone Gly + 1 pt 2,4-D % control, days Average of 12 trials,

Roundup UltraMax 1.6 pt 14 days after treatment 28 days after treatment

Glyphosate Tank Mixes on Cutleaf Eveningprimrose. GA & NC data Gly alone Gly + 1/2 oz Harmony Extra Gly + 1 pt 2,4-D % control, days Average of 12 trials,

Glyphosate Tank Mixes on Cutleaf Eveningprimrose. GA & NC data Gly alone Gly oz Resource Gly + 1 pt 2,4-D % control, days Average of 4 trials,

Glyphosate Tank Mixes on Cutleaf Eveningprimrose. GA data Gly alone Gly + 1 oz Valor Gly + 1 pt 2,4-D % control, days Average of 1 trials,

flumioxazin change from WDG to WP 1 to 2 oz/A mixed with glyphosate – much quicker burndown – residual activity if contacts soil (good for pusley) – enhanced geranium, radish, and primrose control Valor for Burndown

Glyphosate Tank Mixes on Cutleaf Eveningprimrose. GA & NC data Gly alone Gly + 2 oz Valor Gly + 1 pt 2,4-D % control, days Average of 8 trials,

Roundup UltraMax 1.6 pt + Valor 1 oz 14 days after treatment 28 days after treatment

Gly alone Gly + 1 pt Goal Gly + 1 pt 2,4-D Average of 5 trials, % control, days Glyphosate Tank Mixes on Cutleaf Eveningprimrose. NC data.

Gly alone Gly + 1/2 pt Clarity Gly + 1 pt 2,4-D Average of 6 trials, % control, days Glyphosate Tank Mixes on Cutleaf Eveningprimrose. NC data.

Gly alone Gly + 2/3 oz Aim Gly + 1 pt 2,4-D Average of 3 trials, % control, days Glyphosate Tank Mixes on Cutleaf Eveningprimrose. GA & NC data.

Gly alone Gly + 1 pt Direx Gly + 1 pt 2,4-D % control, days Average of 1 trials, Glyphosate Tank Mixes on Cutleaf Eveningprimrose. GA data.

Relative Response of Cutleaf Eveningprimrose to Glyphosate Tank Mixes.* Alone Harmony GT Aim Harmony Extra Goal ResourceValorClarity 2,4-D *Estimates based on GA and NC data from 1999 to 2001.

Roundup + Direx Roundup On farm, Grady County, 2001.

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

Boa alone + 1 oz Valor + 2 oz Valor + 4 oz Resource + 2/3 oz Aim + 1 pt Direx + 1 pt Caparol + 1 pt 2,4-D + 1/2 oz Harmony Ex % control, days Paraquat Tank Mixes on Cutleaf Eveningprimrose. GA data. LSD = Average of 1 trials, 2001.

Summary - Cutleaf Eveningprimrose 1. 2,4-D, glyphosate + 2,4-D, paraquat + 2,4-D 2. glyphosate + Valor or Clarity 3. paraquat + Direx, Valor, Harmony Extra or glyphosate + Aim, Caparol, Direx

Wild Radish

Roundup UltraMax + 1 oz Valor + 2 oz Valor + 4 oz Resource + 2/3 oz Aim + 1 pt Direx + 1 pt Caparol + 1 pt 2,4-D + 1/2 oz Harmony Ext % control, days Tank Mixes with Glyphosate on Wild Radish. GA data, Tift County, LSD = 12 93

Boa alone + 1 oz Valor + 2 oz Valor + 4 oz Resource + 2/3 oz Aim + 1 pt Direx + 1 pt Caparol + 1 pt 2,4-D + 1/2 oz Harmony Ext. % control, days Tank Mixes with Paraquat on Wild Radish. GA data, Tift County, LSD = 12 99

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

2,4-D = preferably 45 days Aim = nothing on label Clarity = 21 d after 1” rainfall Direx = 15 d prior to planting Goal = 30 d or at least three 0.25” rainfalls Harmony Extra = 45 d prior to planting Valor = 30 d prior to planting Plant Back Restriction for Burndown Herbicides

none Cotton Injury to Valor Applied Less Than 30 Days Before Planting. TyTy, 2001 % cotton injury, 18 DAP days before planting *Irrigated at cotton emergence. No weeds present at time of application.

Georgia Cotton - Cultivar Selection* 86.9% transgenic; 12.1% conventional 40.8% Roundup Ready 41.5% stacked gene 4.6% Bollgard *USDA Agricultural Marketing Service Survey, August 2001.

The first 4 to 5 weeks of cotton development is the most critical.

Effect of PRE Herbicides on RR Seedcotton Yield lb/A 1 OT2 OT 1490 a 1070 b a 1560 a 1 OT2 OT 635 b 1560 a 1420 a 1600 a No PREAvg. 10 PRE’s 1 Study in 1998 conducted at Goldsboro, NC. Studies in 1999 conducted at Goldsboro, NC and Tifton, GA. Data pooled over both locations in 1999.

How Important Is Early Season Weed Competition? Can one wait until 4-leaf stage of cotton to initiate weed control? Depends upon: Weed species Weed density Growing conditions

How Important Is Early Season Weed Competition? u About 33 to 66% of the time we can initiate weed control at the 3 to 4 leaf stage of cotton. u If in doubt, apply DNA + Cotoran or Staple u The other 33 to 66% of the time we need a soil- applied herbicide or 2 overtop RU applications.

Weeds Difficult to Control by Glyphosate?

Controlling Yellow and Purple Nutsedge? Nutsedge Control Programs: 1) 2 applications of glyphosate prior to 5th leaf followed by conventional chemistry including 2 lb ai MSMA directed 2) 1 application of glyphosate or Staple Plus prior to 5th leaf followed by 2 lb ai MSMA directed or glyphosate 3) Zorial or Staple?????

Yellow Nutsedge Control by R’up/MSMA Mixtures. 2 Locs, No MSMA+ MSMA 1.3 pt Roundup Ultra (pt) *Control 30 DAT % control

Glyphosate 0.75 lb ae/A+ MSMA 1.3 pt 30 days after treatment

Cotton Injury 10 DAT with R’up/MSMA Mixtures. 2 Locs, No MSMA+ MSMA 1.3 pt Roundup Ultra (pt) *Injury by tank mix significantly greater than Roundup applied alone * % injury * * * *

Weeds Difficult to Control by Glyphosate?

Mid-Season Morningglory Control by Glyphosate & Glyphosate/Staple Mixtures. Things to consider? 1. Morningglory size at time of application (5+ inches here). 2. Will you post-direct with conventional chemistry or glyphosate? Glyphosate Glyphosate + Staple Pitted Smallflower morningglory Loc 1 Loc 2 Loc 1

Roundup Ultra 1.5 pt + Staple 0.6 oz 24 days after treatment - Irrigated, Moultrie, 2000.

18 days after treatment - Irrigated, TyTy, Roundup Original 1.5 pt + Staple 0.8 oz

Glyphosate/Staple Tank Mixtures u DuPont new label allows 0.8 oz of Staple to be applied in mixture with glyphosate.

Controlling Extremely Large Morningglory

Weeds Difficult to Control by Glyphosate?

Hemp Sesbania Control by Glyphosate. Tifton, 2000.* % control *Roundup Ultra applied at 2 pt/A. Experiment conducted under center irrigation. 3 inches7 inches 86 59

Tropical spiderwort, Cairo, GA, Cooperative work with Tim Flanders

Fairly common scene at harvest across the state

present label = –may be applied overtop of 3-12 inch cotton alone –may be directed in mixture with glyphosate in RR cotton but “do not allow spray solution to contact cotton leaves” residual control for Amaranthus, grasses, tropical spiderwort Dual Magnum + Glyphosate Label

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

Palmer T. panicum pusley y. nutsedge % control, late-season LSD ranged from 9 to 12 TD 1 lf TD 1 lf TD 1 lf TD 4 lf TD 4 lf TD + Dual Mag. 4 lf TD timely PD TD 11 d delay TD 11 d delay Weed Response to Touchdown (TD)/Dual Magnum Systems. Attapulgus, 2001.

present label = –may be applied overtop of 3-12 inch cotton alone –may be directed in mixture with glyphosate in RR cotton but “do not allow spray solution to contact cotton leaves” residual control for Amaranthus, annual grasses, tropical spiderwort any concerns?????? Dual Magnum + Glyphosate Label

Roundup UltraMax + 1 pt Dual Magnum POST

GA Locations Taken to Yield in * ** * * * Midville Tifton TyTy Moultrie Attapulgus No negative effect from Dual plus glyphosate applied overtop of 3- to 4-leaf cotton. No negative effect noted in 15 locations in NC.

Conventional options: Caparol + MSMA Cobra + MSMA Cotoran + MSMA Direx + MSMA Linex + MSMA (not labeled) Common Layby Herbicide Options

RR options little to no residualpossible residual glyphosate glyphosate + Aim Layby Herbicide Options

label claims control of: pigweed specieslambsquarters cockleburmorningglory velvetleafspurred anoda smartweedhemp sesbania common ragweed Aim Postemergence-directed

0.5 to 1 oz/A (40 DF) 1% COC Alone or mixed with any registered herbicide Aim Postemergence-directed

timing of application: - cotton at least 6 inches if NO spray contact - cotton at least 12 inches with minimal contact Aim Postemergence-directed

Cotton Response to Aim Directed. Cotton 12 to 24 inches. % cotton injury Location 1, NC Location 2, NC DAT Treatment R’up alone oz Aim * 4 *Primarily injury to cotton stems; stems not “woody”.

Cotton Response to Aim Directed. Cotton 12 to 24 inches. % cotton injury Location 1, GA Location 2, GA DATDAT Treatment R’up alone oz Aim Primarily injury to cotton stems; stems not “woody”. Yield unaffected.

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

Morningglory Control with Roundup + Aim. % control Location 1, GA Location 1, NC Treatment36 DAT14 DAT R’up alone oz Aim

RR options little to no residualpossible residual glyphosate glyphosate + Aim glyphosate + Harvade Common Layby Herbicide Options

Morningglory Control with Roundup + Harvade. % control pitted smallflower Treatment morningglory morningglory R’up alone oz Harvade *Add COC in with Harvade.

RR options little to no residualpossible residual glyphosate glyphosate + Caparol glyphosate + Aim glyphosate + Direx glyphosate + Harvade Layby Herbicide Options

Late-season Effect of Direx Applied with Glyphosate in 14” Cotton Texas panicum smallflower morningglory bristly starbur Florida pusley glyphosate pt Direx Glyphosate applied at 1 and 4 leaf cotton. Attapulgus, 2001.

Label requires 20% boll opening in RR cotton Is there any potential for an earlier application? Pre-Harvest Glyphosate Applications

8 trials conducted in LA, GA, and NC glyphosate applied 1. 7 d prior to last effective bloom date 2. on last effective bloom date 3. 7 d after last effective bloom date d after last effective bloom date 5. 20% boll crack 6. no glyphosate RR Cotton Response to Glyphosate Applied Prior to 20% Boll Opening

7 of 8 trials no negative responses RR Cotton Response to Glyphosate Applied Prior to 20% Boll Opening

RR Cotton Response to Glyphosate Applied Prior to 20% Boll Opening. Tifton, BLEBDLEBD7ALEBD14ALEBD20% CrackNone * *Significantly less than all other treatments. Lint yield/A

Glyphosate Paraquat Harvade vs. Aim Weed Control at Defoliation

Morninglory Leaf and Vine Desiccation. Moultrie, Finsh+ Harvade+AimFinish+ Harvade+ Aim Percent 2 day after treatment LeafVine Finish applied at 21 oz/A, Aim at 0.66 oz/A, Harvade 10 oz/A.

Morninglory Leaf and Vine Desiccation. Moultrie, Finsh+ Harvade+AimFinish+ Harvade+ Aim Percent 7 day after treatment LeafVine 14 day after treatment Finish applied at 21 oz/A, Aim at 0.66 oz/A, Harvade 10 oz/A.

Treat bermudagrass and other perennials Weed Control After Harvest