1. 2016 Wheat Weed Control Treated Untreated A. Stanley Culpepper
University of Georgia
Tifton, GA

2. Discussion Topics 1. Review traditional control methods
2. Discuss new approaches
1. Broadleaf control
2. Ryegrass control

3. Controlling Broadleaf Weeds
1. Harmony Extra fb MCPA or 2,4-D
2. Harmony Extra + MCPA or 2,4-D
3. 2,4-D alone
4. MCPA alone
5. Harmony Extra alone
Most effective program
Least effective program

4. Controlling Broadleaf Weeds
1. Harmony fb MCPA or 2,4-D
2. Harmony TS + MCPA or 2,4-D
3. 2,4-D alone
4. MCPA alone
5. Harmony Extra alone
Most effective program
Least effective program

5. MCPA vs 2,4-D CROP RESPONSE: MCPA: 2 tiller to full tiller wheat
2,4-D: full tiller wheat
WEED RESPONSE:
Similar on small weeds; 2,4-D better on larger weeds. Both outstanding on radish.

6. Ryegrass Control in Wheat
1. A genetic stud– will develop resistance to ALL herbicides more quickly than any other known plant.
2. Extremely competitive with grain production.
3. Great options available ……….

7. IF YOU DON’T HAVE RESISTANCE
Ryegrass Control in Wheat
1. A genetic stud– will develop resistance to ALL herbicides more quickly than any other known plant
2. Extremely competitive with grain production.
3. Great options available ……….
IF YOU DON’T HAVE RESISTANCE

8. Non-treated control
Hoelon 2X rate

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

10. Non-treated control
Axial XL 2X rate

11. Annual Ryegrass – In Crop
ACCase Inhibition
Holeon
Axial
ALS Inhibition
Osprey
PowerFlex
PSII and VLCFA
Axiom
Inhibit Microtubule
Prowl

12. Resistance management:
Ryegrass Control in Wheat
Resistance management:
Axial and Hoelon have same mode of action. Treat a field only once every two years with either.
Osprey and PowerFlex have same mode of action. Treat a field only once every two years with either.
Timeliness is critical
ACY
Again, our concern with Hoelon in much of NC, especially in the Piedmont, is resistance.

13. Proper Timing of POST Materials Timeliness is critical !!!
With normal planting date, generally
best to apply around Christmas
ACY

14. Ryegrass Resistant to ALL POST’S
Efforts underway to understand impacts of deep turning.

15. Ryegrass planted 0.5 inch followed by deep turning.
Ryegrass planted 0.5 inch without tillage.

16. Deep turning reduces ryegrass emergence. Webster, 2014.
809,000
Plant/A
1210
Plant/A
Control
Deep Turn
Ryegrass was planted with a grain drill at a depth of 0.5 inch followed by no tillage (control) or by deep turning seeds 10 to 12 inches deep. Plant/A are the number of plants that emerged by late-season.

17. Ryegrass Resistant to ALL POST’S
Efforts underway to understand impacts of deep turning.
New products:
Zidua
Fierce (section 24 c)

18. Zidua: Effective on Ryegrass
Outstanding residual ryegrass control!
Suppression of few broadleaf weeds.
If Zidua is activated prior to ryegrass emergence, excellent control expected! If ryegrass is up when applied then control of emerged plants not likely.

19. Zidua: Effective on Ryegrass
Delayed preemergence:
Seed planted at least 0.75” deep
80% of seed germinated with 0.5” shoot
0.75 to 1 oz (sands); 1 to 1.25 oz (med texture)
Early POST (spike through 4-tiller):
Seed planted at least 0.5” deep
1 to 2 oz/A

20. UGA Data With Zidua on Ryegrass
Ryegrass control; Zidua 1 oz/A activated before emergence.
Loc 1 2 3 4 5 6
Avg % 92 93 99 96
W2-11; W3-11; W14-11; W5-12; W13-12, W1-13

21. UGA Data With Zidua on Ryegrass
Ryegrass control; Zidua 1 oz/A activated before emergence.
Loc 1 2 3 4 5 6
Avg % 92 93 99 96
Ryegrass control; Zidua 1 oz/A applied to spike wheat.
Loc 1 2 3 4 5 6 7 8
Avg % 87
100 71 74 77 59 82 78
W2-11; W3-11; W14-11; W5-12; W13-12, W1-13
W11-12; W14-12; W1-12; W7-12; W8-12; W1-13; W2-13; W7-13

22. Fierce (Section 24 c GA Label)
Good ryegrass & I think broadleaf control!
Must walk slowly with injury concerns.

23. Fierce (Section 24 c GA Label)
Outstanding ryegrass & I think broadleaf control!
Must walk slowly with injury concerns.
Application between spike and 2 lf wheat:
Seed planted between 1 and 1.5 inch deep
Apply at 1.5 oz/A
Do not apply on sands!!!!
Do not mix with anything but water!!!
MUST BE ACTIVATED PRIOR TO WEEDS ½”

24. UGA Data With Fierce on Ryegrass
Ryegrass control with Fierce applied spike to wheat.
Loc 1 2 3 4 5 6
Avg %
100 95 99 97
Residual component must be activated for
acceptable control. (100 vs 71)
W7-12; W8-12; W3-13; W4-13; W7-13; W11-13

25. UGA Data With Fierce on Radish
Radish control with Fierce applied spike to wheat.
Loc 1 2 3 4
Avg % 92
100 99 98 97
Residual component must be activated for
acceptable control.
W3-13; W4-13; W7-13; W11-13

26. Summary 1. Great options for broadleaves
Using same herbicide MOA on a piece of ground guarantees resistance in 3 yr
Walk slowly with Fierce!
Do not treat the same ground 2 years in a row with Fierce or Zidua!