2001 Cotton Production Workshop

transcript

Waiting until spring to control weeds

glyphosate or paraquat

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

Average of 12 trials, 1999-2001.

Roundup UltraMax 1.6 pt

14 days after treatment 28 days after treatment

100Gly alone

Gly + 1/2 ozHarmony ExtraGly + 1 pt 2,4-D%

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100Gly alone

Gly + 2-3 ozResourceGly + 1 pt 2,4-D%

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Glyphosate Tank Mixes on Cutleaf Eveningprimrose. GA data.

100Gly alone

Gly + 1 ozValorGly + 1 pt 2,4-D%

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Average of 1 trials, 2001.

• 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

100Gly alone

Gly + 2 ozValorGly + 1 pt 2,4-D%

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Roundup UltraMax 1.6 pt + Valor 1 oz

14 days after treatment 28 days after treatment

100 Gly alone

Gly + 1 pt Goal

Gly + 1 pt 2,4-D

Glyphosate Tank Mixes on Cutleaf Eveningprimrose. NC data.

100 Gly alone

Gly + 1/2 pt Clarity

Gly + 1 pt 2,4-D

Glyphosate Tank Mixes on Cutleaf Eveningprimrose. NC data.

100 Gly alone

Gly + 2/3 ozAim

Gly + 1 pt 2,4-D

100 Gly alone

Gly + 1 ptDirex

Gly + 1 pt 2,4-D%

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Glyphosate Tank Mixes on Cutleaf Eveningprimrose. GA data.

Relative Response of Cutleaf Eveningprimrose to Glyphosate Tank Mixes.*

*Estimates based on GA and NC data from 1999 to 2001.

Roundup

+ Direx Roundup

On farm, Grady County, 2001.

Roundup UltraMax (1.6 pt) + 1.5 pt Caparol

Wheat Response to Glyphosate Applied Alone and in Mixture with Caparol. Ponder Farm, 2001; 16 DAT.

100Boa 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

Paraquat Tank Mixes on Cutleaf Eveningprimrose. GA data.

LSD = 13

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

100 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

71 73 7769

Tank Mixes with Glyphosate on Wild Radish. GA data, Tift County, 2001.

LSD = 12

100Boa 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.

67 70 68 67

Tank Mixes with Paraquat on Wild Radish. GA data, Tift County, 2001.

LSD = 12

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 21 14 7 0

Cotton Injury to Valor Applied Less Than 30 Days Before Planting. TyTy, 2001

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.1

1 OT 2 OT

1490 a

1070 b

1998 1999

1460 a

1560 a

1 OT 2 OT

1560 a

1420 a

1600 a

No PRE Avg. 10 PRE’s

1Study 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 IsEarly 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 IsEarly Season Weed Competition?

About 33 to 66% of the time we can initiate

weed control at the 3 to 4 leaf stage of cotton.

If in doubt, apply DNA + Cotoran or Staple

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, 1999 -2000.

No MSMA + MSMA 1.3 pt

Roundup Ultra (pt)

*Control 30 DAT.

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, 1999.

0 0.5 1 1.5 2

No MSMA + MSMA 1.3 pt

Roundup Ultra (pt)

*Injury by tank mix significantly greater than Roundup applied alone

2025 27

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 73 55 89

Glyphosate + Staple 93 76 97

Pitted Smallflower

morningglory 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, 2001.

Roundup Original 1.5 pt + Staple 0.8 oz

Glyphosate/Staple Tank Mixtures

DuPont new label allows 0.8 oz of Staple to be applied in mixture with glyphosate.

Controlling Extremely Large Morningglory

Hemp Sesbania Control by Glyphosate. Tifton, 2000.*

*Roundup Ultra applied at 2 pt/A. Experiment conducted under center irrigation.

3 inches 7 inches

Tropical spiderwort, Cairo, GA, 2001. 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

glyphosate @ 4 lf + 1 pt Dual MagnumAttapulgus, 2001

*Irrigated within 48 hrs.

PalmerT. panicumpusleyy. nutsedge

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

GA Locations Taken to Yield in 2001.

Midville

TiftonTyTy

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 optionslittle to no residual possible residual

glyphosate

glyphosate + Aim

Layby Herbicide Options

• label claims control of:

pigweed species lambsquarters

cocklebur morningglory

velvetleaf spurred anoda

smartweed hemp sesbania

common ragweed

Aim Postemergence-directed

• 0.5 to 1 oz/A (40 DF)

• 1% COC

• Alone or mixed with any registered herbicide

• timing of application:

- cotton at least 6 inches if NO spray contact

- cotton at least 12 inches with minimal contact

Cotton Response to Aim Directed. Cotton 12 to 24 inches.

% cotton injury

Location 1, NC Location 2, NC

DAT DAT

Treatment 5 12 3 11

R’up alone 0 0 0 0

+ 0.6 oz Aim 2 1 12* 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

DAT DAT

Treatment 5 14 35 8 23 36

R’up alone 0 0 0 0 0 0

+ 0.6 oz Aim 25 18 0 33 13 2

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

Treatment 36 DAT 14 DAT

R’up alone 82 92

+ 0.6 oz Aim 95 100

glyphosate

glyphosate + Aim

glyphosate + Harvade

Common Layby Herbicide Options

Morningglory Control with Roundup + Harvade.

% control

pitted smallflower

Treatment morningglory morningglory

R’up alone 82 92

+ 8 oz Harvade 95 100

*Add COC in with Harvade.

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

+ 1.5 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

4. 14 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, 2001.

7BLEBD LEBD 7ALEBD 14ALEBD 20% Crack None

*Significantly less than all other treatments.

Glyphosate

Paraquat

Harvade vs. Aim

Weed Control at Defoliation

Morninglory Leaf and Vine Desiccation. Moultrie, 2001.

Finsh + Harvade +Aim Finish + Harvade + Aim

2 day after treatment

Leaf Vine

Finish applied at 21 oz/A, Aim at 0.66 oz/A, Harvade 10 oz/A.

Morninglory Leaf and Vine Desiccation. Moultrie, 2001.

Finsh + Harvade +Aim Finish + Harvade + Aim

Leaf Vine

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

2001 Cotton Production Workshop

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