1. Giant Ragweed Control in Cotton
Larry Steckel and Chris Main
University of Tennessee

2. Giant Ragweed Moves into Fields from Borders

3. Giant Ragweed Begins to Spread

4. 2 Shots of Roundup Original Max

5. Spreads Throughout the Field

7. 40 (2”) + 88 (6”) + 88 (18”) oz/A Roundup WM

8. 2008 Weed Control Manual for Tennessee
Field Crops • Forage Crops • Pastures • Farm Ponds • Harvest Aids
Contents 4
Burndown Herbicides 6
Tobacco 56
Calibration 83
Resistant Horseweed 7
Wheat 59
Herbicide Drift 87
Corn 10
Sunflowers 63
Grazing Restrictions 96
Grain Sorghum 23
Forage & Pastures 66
Price List
104
Cotton 29
Farm Ponds 79
Rotation Restrictions
108
Soybeans 47
Sprayer Cleaning 82
Herbicide Index
114

9. Giant Ragweed Biology

10. Giant Ragweed Moves into Fields from Borders

11. Objectives
Evaluate several Pre applied herbicides for giant ragweed control
Caparol, Cotoran, Direx and Staple
Determine if Envoke or Staple applied Post-emergence could help provide giant ragweed control

12. Application Information & Design Pre Study
Randomized Complete Block
4 replications
Herbicides were applied with backpack CO2 charged sprayer
10 gpa
80015VS
Applications were made:
Pre - May 1
Horseweed control ratings taken 7, 21 and 40 DAT

13. Objectives
Evaluate several Pre applied herbicides for giant ragweed control
Can Pre applied herbicides provide giant ragweed control?
Determine if Envoke or Staple applied Post-emergence could help provide giant ragweed control

14. NO…Not in 2007!

15. Objectives
Evaluate several Pre applied herbicides for giant ragweed control
Determine if Envoke or Staple applied Post-emergence could help provide giant ragweed control

16. Application Information & Design Post Study
Randomized Complete Block
4 replications
Herbicides were applied with backpack CO2 charged sprayer
10 gpa
80015VS
Applications were made:
Roundup WeatherMax applications OT applied 1st and 4th cotton node
Post – June 1
Hooded – June 25
Horseweed control ratings taken 7, 14, 21, 30 and 40 DAT

17. Giant Ragweed Control Applications made to 8 node cotton 20 40 60 80
Roundup WeatherMax applied at 22 ozs/A at 1st and 4th nodes
Applications made to 8 node cotton
Staple LX 3.8 oz/A
Envoke 0.15 oz/A
LSD = 13 20 40 60 80
100
% Control 40 DAT

18. Staple LX

19. Summary of Post Applications
Envoke and Staple LX provided about 60 to 70% control
Not enough
Would that much control help with follow-up hooded Ignite applications?

20. Envoke over the top + Ignite hooded

21. 22 oz/RWM 1st/4th nodes fb 0.15 oz Envoke fb 29 oz Ignite hooded
22 oz/RWM 1st/4th nodes fb Ignite hooded
22 oz/RWM 1st/4th nodes fb 0.15 oz Envoke fb 29 oz Ignite hooded

22. Summary of Timing
Envoke or Staple LX provided enough giant ragweed suppression to allow better control with follow-up hooded applications of Ignite
Ignite in mid-summer applications can provide very effective control of giant ragweed
Post direct
Over the top of LL varieties

23. County Std. Test #1 Main et al 2007 Gin Turnout Lint Yield Length
Strength
Uni-formity
Leaf
Loan Value
Rank
Company
Variety
(%)
(lb./acre)
Mic
(inches)
(g/tex)
Grade
(¢/lb.) 1
Phytogen
310 R
39.2
771
3.8
1.04
26.3
80.3 4
48.76 2
Delta & Pine Land
444 BG/RR
39.0
769
3.5
1.06
26.8
79.5
49.53 3
370 WR
38.6
740
3.9
26.5
80.4
48.15
445 BG/RR
39.5
725
3.7
1.07
29.2
80.1
51.35 5
Stoneville
4554 B2RF
36.6
712
27.5
80.9
49.05 6
4427 B2RF
37.3
705
3.6
26.1
47.08 7
Croplan Genetics
3520 B2RF
36.4
644
3.4
1.08
24.2
79.7
46.16 8
Americot
1532 B2RF
36.3
641
80.2
47.32 9
Dyna-Gro
2242 B2RF
35.7
635
24.1
46.14 10
2100 B2RF
34.7
604
3.2
1.05
24.0
79.0
45.84 11
4020 B2RF
35.4
572
47.14 12
117 B2RF
37.9
560
27.3
80.5
44.26
Mean
37.2
673
25.9
80.0
47.57
LSD (0.05)
1.4 56
0.1
0.01
0.9
0.6
0.38
2.37 CV
7.06
35.08
12.10
3.43
9.31
1.40
19.20
10.03
Main et al 2007 23

24. County Std. Test #3 Main et al 2007 Gin Turnout Lint Yield Length
Strength
Uni-formity
Leaf
Loan Value
Rank
Company
Variety
(%)
(lb./acre)
Mic
(inches)
(g/tex)
Grade
(¢/lb.) 1
FiberMax
1600 LL
34.0
645
3.7
1.11
27.8
80.6 4
51.43 2
1735 LLB2
29.9
586
3.4
29.0
80.3
49.58 3
955 LL
29.7
527
3.6
1.07
30.8
80.9
50.96
958 LL
30.4
500
1.10
80.7
52.90 5
966 LL
30.1
469
1.09
30.2
80.8
52.75
Mean
545
29.5
51.55
LSD (0.05)
3.3
108
0.1
0.22
2.3
0.9
0.39
1.92 CV
11.16
36.46
17.49
3.72
9.36
0.97
16.57
7.24
Main et al 2007 24

25. Giant Ragweed Management
Contain it at the field edges!!!
Staple and Envoke can help control giant ragweed
Ignite is the most effective post option in cotton
Post direct
Post over the top (variety selection issues)

26. Questions