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
Comments?