2011: impact of cover crop residue and tillage on the control of glyphosate-resistant palmer...

2011: Impact of cover crop residue and tillage on the control of glyphosate-resistant Palmer amaranth

Staple + Reflex + Direx PRE

Roundup WMax + Parrlay POST

Direx + MSMA Layby

Palmer amaranth control before and after GR Palmer resistance in cotton!

Roundup

Roundup

Roundup

Georgia counties confirmed to be infested with glyphosate-resistant Palmer amaranth.

2004 – 1 county

2005 – 2 counties

2006 – 7 counties

2007 – 11 counties

2008 – 18 counties

2009 – 13 counties

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

500,000

230 K

25028 K

309 K

Giant ragweed

450 K

Number of Seed Produced per Plant Glyphosate-Resistant Weeds in US

Ragweed = Harrison et al. 2001; johnsongrass = Warwick and Black (1983); horseweed = Regehr and Bazzaz (1979); waterhemp = Nordby and Hartzler (2004); Palmer amaranth = Macrae et al (2009).

Johnson-grass

Horseweed Waterhemp Palmer amaranth

Palmer amaranth seed production allows for rapid field domination

Year 1 Year 3 to 4

Role of pollen movement and gene-flow in the spread of herbicide resistance

In-field pollen movement

Distance (m) from source of resistance

1 5 10 25 50 75 100 150 200 250 300

% R

esis

tan

t o

ffsp

rin

g p

er p

aren

t p

lan

t

0

20

40

60

80

100

20062007

Amaranthus rudis Amaranthus palmeri

Tennessee

Missouri

Illinois

MississippiGeorgia

S Carolina

N Carolina

Alabama

Louisiana

Arkansas

GR pigweed in the mid-south and southeast

Steckel 2010

Can not survive with herbicides alone any longer

York 2010

Hand WeedingHand Weeding

2010: Herbicide input: $90 million

York 2010Hand WeedingHand Weeding

Over $16 million spent during 2010 ($23.70 on 53% of our acres)

Over $15 million spend during 2009

92% of GA growers handweeding 53% of the 2010 crop

Few growers Few growers

Most growers by far

Grower mentality of tillage vs. conservation tillage

0

20

40

60

80

100

Before (2004) After (2008)

5

% a

cres

*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

tillage GA Counties#

0 0

1-9 Worth, Pualski, Tift, Berrien, Echols, Turner, Brooks, Pierce,

Marion, Grady,

10

10-19 Emanual, Montgomery, Atkins, Coffee, Lowndes, Dooly, Wilcox,

Thomas, Crisp, Schley, Webster

11

20-29 Bullock, Jefferson, Treutlen, Wheeler, Daugherty 5

30-50 Effingham, Telfair, Tattnall, Dodge, Toombs, Jeff Davis, Bleckly,

Early, Lanier, Irwin, Colquitt, Lee

13

>50 Jenkins, Johnson, Washington, Screven, Wayne, Laurens, Randolf,

Decatur, Seminole, Miller, Taylor Ben Hill

12

Although the agricultural community is committed to the benefits of conservation tillage, survival of the family farm is more critical.

Thus, understanding when tillage is required and determining how to implement tillage to compliment conservation tillage systems while having minimal impacts on the environment are needed if both the family farm and conservation tillage are expected to survive the threat of herbicide resistant weed.

LONG TERM GOAL

Objective

Develop an economically effective integrated program for the control of

GR Palmer amaranth in cotton.

Roundup applied three times starting on ½ Palmer provided no control

Four Tillage Options

Deep Inversion

(12 to 16 inches)

Strip into weeds

Four Tillage Options

Deep inversion

followed by RyeHeavy residue

(1.5 bu/A)

Staple + Reflex + Direx PRE

Roundup WMax + Parrlay POST

Direx + MSMA Layby

Palmer amaranth control of 95% achieved by herbicide program!

GR Palmer amaranth control by tillage and cover crop residue. 2009 & 2010. 21 DAP.*

0

20

40

60

80

100

0 d

50 c60 b

Weeds

*No herbicide

Inversion + rye

Deep inversion

75 a

Rye

%

In the rye, control loss was in the strip

GR Palmer amaranth control by tillage, cover crop residue, and herbicides. 2009 & 2010 At harvest.*

0

20

40

60

80

100

76 b 78 b

Weeds

*RR System: Diuron + Reflex + Staple fb Roundup + Parrlay fb Direx + MSMA

Inversion + rye

Deep inversion

94 a

Rye

%59 c

Staple + Reflex + Direx PRE

Roundup WMax + Parrlay POST

Direx + MSMA Layby

Weeds Deep Tillage

Palmer amaranth response to deep tillage. Macon County, GA. 2009.

Staple + Reflex + Direx PRE

Roundup WMax + Parrlay POST

Direx + MSMA Layby

Weeds Rye cover

Palmer amaranth response to cover crops. Macon County, GA. 2009.

Staple + Reflex + Direx PRE

Roundup WMax + Parrlay POST

Direx + MSMA Layby

Weeds

Palmer amaranth response to deep tillage and cover crops. Macon County, GA. 2009.

Deep tillage

Rye cover crop

GR Palmer amaranth influence on cotton lint yield (lb/A) in the Roundup system.*

0

200

400

600

800

592 c690 b

Weeds

*RR System: Diuron + Reflex + Staple fb Roundup + Parrlay fb Direx + MSMA

Inversion + rye

Deep inversion

790 a

Rye

480 d

Dryland Conservation Tillage

Prowl + Reflex PRE

Roundup + Dual POST

Diuron + MSMA PD

Prowl + Reflex PRE

Ignite + Dual POST

Diuron + MSMA PD

Applications must be timely with Ignite

GR Palmer amaranth control by tillage, cover crop residue, and herbicides. 2009 & 2010. At harvest.*

0

20

40

60

80

10099 a 99 a

Weeds

*Ignite System: Diuron + Reflex + Staple fb Ignite + Parrlay fb Direx + MSMA

Inversion + rye

Deep inversion

99 a

Rye

%

94 b

0

200

400

600

800

680 bc710 ab

Weeds

*Ignite System: Diuron + Reflex + Staple fb Ignite + Parrlay fb Direx + MSMA

Inversion + rye

Deep inversion

770 a

Rye

%

625 c

GR Palmer amaranth influence on cotton lint yield in the Ignite system. 2009 & 2010.*

1. Strip tillage into weeds

2. Strip tillage into rye.

3. Strip tillage into rye/deep turning.

ON FARM STUDIES

Tillage/Cover Crop Options

Influencing Palmer Emergence(On farm study, TN)

WeedsRye

(large)

Deep Turn

+ Rye

101

10 sq m

45

10 sq m

44

10 sq m

Influencing Palmer Emergence(On farm 10 acre study, Macon Co. Georgia)

WeedsRye

(large)

Deep Turn

+ Rye

Gram. + Direx BD; Prowl + Reflex PRE; RU + Dual POST;

Direx + MSMA layby

8242

plants/A

4371

plants/A

446

plants/A

No Deep Tillage Deep Turn

No Herbicide Treatment

Number of Palmer Amaranth Plants During Early Season. Macon Co., Georgia 2008.*

Influence of burial depth on Palmer amaranth emergence

Depth of burial (inches)

0.5" 1" 4" 16"

Pe

rce

nt (

%)

em

erg

en

ce

0

10

20

30

40

50S-Palmer amaranthR-Palmer amaranth

Keeley et al. (1987) reported 36-44% emergence at 0-1”, 7% at 2”, and 2% at 3”.

Length of burial (months)

0 6 12 18 24 30

Per

cent

(%

) ge

rmin

atio

n

0

20

40

60

80

100

Palmer amaranth seed germination as affected by length of burial

Depth of burial (inches)

0.5 1 4 16

Per

cent

(%

) ge

rmin

atio

n

30

40

50

60

70

Palmer amaranth seed germination as affected by depth of burial

1.Work together!

2. Integrated programs are required to control GR Palmer amaranth in cotton.

3.Deep turning, rye cover, and deep turing + rye will greatly improve control.

4. Incentives to assist in grower adoption of heavy residue.

5.Find more funds to expand NRCS Pilot Program.

SUSTAINING COTTON PRODUCTION

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