2014 Weed Control Tactics – Alabama Vegetable Conference

Stanley CulpepperUGATifton Campus

Weed Control Responsibilities

Weed Management At Its Best

Mechanical Cultural

Herbicide/Fumigant

Agronomic Weed Control

Mechanical

Cultural

Herbicide

Resistance Impacts Agronomic Crops

Changes in Herbicide Management2002: $24/A 2010: $63/A

Roundup Burndown

Roundup POST 1

Roundup POST 2

Roundup + diuron PD

Roundup + Valor Burndown1

Gramoxone + Reflex + Direx PRE

Roundup + Staple POST 1

Roundup + Dual POST 2

Direx + MSMA PD

Photo by A.C. York 2010

2004: 17% of growers hand-weeded 5% cotton acres at $2.40/A

2010: 92% of growers hand-weeded 52% cotton acres at $23.70/A

Tillage is now a common scene

2004: 13.1% of cotton acres cultivated2010: 32.1% of cotton acres cultivated

Herbicide incorporation: 264,266 A (26.7%) Deep turn: 256,075 A last 3 yr

Weed Management At Its Best

Mechanical Cultural

Herbicide/Fumigant

DIVERSIFICATION

Replacing Methyl Bromide – Great Progress

Breakout session-this afternoon

Herbicides for Specialty Crops

Many believe few options currently available with few

products on the horizon!

New GA Veggie Labels Last 7 Yr

1. Chateau tomato RM

2. Chateau pepper RM

3. Chateau eggplant RM

4. Chateau watermelon RM

5. Chateau cantaloupe RM

6. Chateau cucumber RM

7. Chateau squash RM

8. Dual Magnum pepper topical

9. Dual Magnum broccoli topical

10. Dual Magnum cabbage topical

11. Dual Magnum collards topical

12. Dual Magnum cauliflower topical

13. Reflex tomato preplant

14. Reflex pepper preplant

15. Caparol in Okra

16. Sandea in Okra

17. Dual Mag. Carrot

18. Dual Mag. Watermelon

19. Dual Mag Cantaloupe

20. Dual Mag. Sweet Potato

21. Dual Mag. POST in Tomato

22. Dual Mag. POST in Beans

23. Dual Mag. POST in Kale

24. Dual Mag. POST in Collard

25. Reflex in Watermelon

26. Reflex in Squash

27. Reflex in Pumpkin

28. Treflan - Intercropping

Grower Standard + Future Product?

Grower Standard (not a check!!)

Notice pigweed

Herbicides More Available for GA Vegetable Growers

4 NEW HERBICIDE USES PER YEAR ON

AVERAGE OVER LAST 7 YEARS

Why So Successful?

University/Commodity Commission/Department of Ag

Why So Successful?

University/Commodity Commission/Department of Ag

Syngenta

Indemnified Labels

Valent

3rd party registration

Why So Successful?

University/Commodity Commission/Department of Ag

Syngenta

Indemnified Labels

Valent

3rd party registration

IR-4

Limitations and Concerns

1. Limited number of scientists working in specialty crops.

2. Most growers scared to death of herbicides

Limitations and Concerns

1. Limited number of scientists working in specialty crops.

- most of our labels 10-12 studies

- new corn label 550 studies

Dual PRE Dual POST

Herbicide Injury

Greatly influenced by excess moisture, cold, and incorrect spray calibration.

Herbicides Can Only Be As Good As the Person Applying Them

1. Droplet Size –nozzle, pressure, speed

GreenLeaf TwinJet Air Induction

There is a fine line between drift management and weed control!

Table 1. ASAE S-572.1 Spray Tip Classification by Droplet Size1.

Category Symbol Color CodeApproximate

VMD2

(Microns)

Extremely Fine XF PURPLE ~50

Very Fine VF RED <136

Fine F ORANGE 136-177

Medium M YELLOW 177-218

Coarse C BLUE 218-349

Very Coarse VC GREEN 349-428

Extremely Coarse

XC WHITE 428-622

Ultra Coarse UC BLACK >622

1Source: TeeJet Technologies Catalog 51, page 136.2VMD = Volume median diameter.

Herbicides Can Only Be As Good As the Person Applying Them

1. Droplet Size –nozzle, pressure, speed

2. Adjuvants – some products need

Photo credit: Webster

Herbicides Can Only Be As Good As the Person Applying Them

1. Droplet Size –nozzle, pressure, speed

2. Adjuvants – some products need

3. Persistence

No Reflex Reflex 1 pt/A applied 205 days before transplanting

Herbicides Can Only Be As Good As the Person Applying Them

1. Droplet Size –nozzle, pressure, speed

2. Adjuvants – some products need

3. Persistence

4. Relationship with mulch

Roundup Preplant No Roundup

Sandea Dissipation on Mulch

Event

0 1 2 3 4 5

hal

osu

lfu

ron

ret

ain

ed (

%)

0

20

40

60

80

100

% halosulfuron Dry % halosulfuron Wash off

65%

6%

Herbicides Can Only Be As Good As the Person Applying Them

1. Droplet Size –nozzle, pressure, speed

2. Adjuvants – some products need

3. Persistence

4. Relationship with mulch

5. Labels – www.cdms.net

6. Extension/Manufacture/Dealer

Weed Management At Its Best

Mechanical Cultural

Herbicide/Fumigant

DIVERSIFICATIONMechanical

• Tillage–Pre-plant–cultivation–after harvest

No Deep Tillage Deep Turn

No Herbicide Treatment

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

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

Influence of burial depth on Palmer amaranth emergence

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

Deep Turn Drilled

Nutsedge Number 1 Problem in Plastic

Don’t plow unless you have to!!!!!!!!!!

Weed Management At Its Best

Mechanical Cultural

Herbicide/Fumigant

DIVERSIFICATIONCultural

• Crop rotation• Plant population• Row spacing• Planting date• Cover crops

Rolling Creates a Mulch that is Critical in Reducing Palmer amaranth Emergence

After Cover is Terminated and it Rains; Planting will be Ideal for a Significant Amount of Time

70 to 95% control in

middle

Rye Mulch Reduces Palmer Emergence

Rye/Mulch System

0

20,000

40,000

60,000

80,000

7830 b

88,015 d

30,350 c

no herbicide

no rye

2465 a

Palmer amaranth plants per acre as influenced by herbicide, rye cover crop, and fumigant.

no herbicide

rye

herbicides

no rye

herbicides

rye

0

10,000

20,000

30,000

40,000

50,000

60,000

1740 b

62350 c

2030 b

no herbicide

no rye

435 a

Annual grass plants per acre as influenced by herbicide, rye cover crop, and fumigant.

no herbicide

rye

herbicides

no rye

herbicides

rye

0

10,000

20,000

30,000

40,000

50,000

8845 c

44,805 d

5945 b

no herbicide

no rye

2900 a

Yellow nutsedge plants per acre as influenced by herbicide, rye cover crop, and fumigant.

no herbicide

rye

herbicides

no rye

herbicides

rye

Rye/Mulch System

Fumigant under mulch if wanted

Rye/Mulch System

Two Biggest Challenges:

1.Time required to get rye established2.Delay in maturity

BIOLOGY

Integrated to remain

sustainable

Management

programs

Diversity and Integration = Survival

Rapid Growth Becoming Extremely Large

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

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

Weakness of Pigweeds

1. Emergence depth!

2. Seed life longevity?

3. Light requirement for emergence.

Nutsedge Tuber Production: The Key

YEAR 1: 10 plants (tuber) survive fumigation

35,000 plants ready for year 2

YEAR 2: control = 95% control (1750 plants survive)

6,125,000 plants ready for year 3

YEAR 3: control = 95% control (306,250 plants survive)

1,071,875,000 plants ready for year 4

About 3 wk after emergence = tubers

ROTATE DISKING WITH ROUNDUP EVERY 3 WKS. ADD SANDEA IN WITH ROUNDUP ONCE IF NOT CARRYOVER PROBLEMS

Non-treated control Hoelon 2X rate

Non-treated control PowerFlex 3X rate or Osprey at 3X rate

Non-treated control Axial XL 2X rate

Non-treated control Was A Future Product

EPA will have great influence

1. Regulatory

2. More difficult to get new tools

3. Loss of old tools

4. Media sensitivity

5. More paperwork

6. Required training

INDUSTRY

Georgia Department of Agriculture Commissioner Gary Black

Questions/Comments

Culpepper, University of Georgia, Tifton Campus

Cotton/Melon Intercropping

• Melons planted as normal

• Cotton generally planted about 3 week later.

• GA acreage exceed 3000 during 2013

Cotton/Cucurbit Intercropping

Cantaloupe SquashWatermelon

30 days after transplant

Cantaloupe-Cotton Intercropping

Cantaloupe Cotton

Yield No reduction 0-12% reduction

Crop value 17% increase >1,000 increase

Watermelon-Cotton Intercropping

Watermelon Cotton

Yield No reduction 12-18% reduction

Crop Value 14% increase >1,000 increase

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