K. M. Eason powerpoint for the Sigma Xi Student Research Showcase

1. Response of Dryland Peanut
Cultivars to Herbicide
Tank-Mixtures
Utilizing Paraquat
K. M. Eason1,
R. S. Tubbs1, T. L. Grey1, X. S. Li2
The University of Georgia1, Auburn University2

2. • Introduction
• Previous Research
• Objective & Hypothesis
• Materials & Methods
• Results
• Summary
• Future Research

3. *Virginia Carolinas peanuts
Background – What is a Peanut?
Here in Georgia, we grow
runner-type peanuts for
peanut butter because of
their high oleic qualities that
are good for PB production!
Peanuts are a legume crop
Their fruit grows underground &
the peanut is grown inside the pod.
There are four types:
Runner
Spanish
Virginia
Valencia
Peanut is an indeterminate crop;
meaning it will continue putting on
pods throughout the entire season.

4. Background, cont.
• In 2016, Georgia farmers produced 1.3 million metric tons of
peanuts (Arachis hypogaea L.)* making it a leading industry in GA.
• Half was produced under non-irrigated (dryland) conditions
• There is little information available on the interaction between herbicides
and peanut cultivars under dryland conditions.
• Farmers want the highest yield possible using the lowest input costs
*USDA National Agricultural Statistics Service 2016 Survey

5. • Weed control is crucial to achieving high yield
• Weeds compete with crops for nutrients, water, and sunlight.
• Weeds in the field can cause:
• Yield reduction, grade/premium decrease, & harvest impediment
Background – The War with Weeds

6. • Currently, weed control programs
in Georgia utilize paraquat as an
effective postemergence herbicide.
• In order to broaden the weed
control spectrum while limiting the
probability of resistance, paraquat
is mixed with other postemergence
herbicides before application.
• Paraquat
• Photosystem I Inhibitor
• Non-selective
• Fast acting / effective
• Affordable
Background –
Paraquat
Paraquat injury (spotty chlorosis & necrosis)

7. Previous Research
The following work has previously been completed. This
research allowed for the creation of my hypothesis:
• Preemergence herbicide testing with paraquat +
bentazon tank-mix1
• Only on ‘Georgia Green’ cultivar
• Different herbicide tank-mixes with paraquat
• Use of bentazon with paraquat to reduce injury2
1 T. L. Grey, & G. R. Wehtje. 2005. Residual Herbicide Weed Control Systems in Peanut. Weed
Technology, 19(3), 560-5671
2 G. R. Wehtje et al. 1992. Influence of Bentazon on the Phytotoxicity of Paraquat to Peanut (Arachis
hypogaea) and Associated Weeds. Weed Science, 40(1), 90-95.

8. Hypothesis
Objectives
• Postemergent herbicide tank-mixes that included
four active ingredients impact yield more, Improve weed control,
& lessen injury when compared to tank-mixes with less than four
active ingredients.
• Evaluate postemergence herbicide tank-mixtures including:
• paraquat, S-metolachlor, acifluorfen + bentazon, acetochlor
• Evaluate the effects on runner-type peanut cultivars under
non-irrigated conditions

9. Experimental Design: Split-Plot design with 4 replications
Main effect: Herbicide Treatment
1. PRE1 + paraquat2 (14 DAP*) + paraquat3 (28 DAP)
2. PRE + paraquat + acifluorfen4 + bentazon5 (28 DAP)
3. PRE + paraquat + acifluorfen + bentazon + S-metolachlor6 (28 DAP)
4. PRE + paraquat + acifluorfen + bentazon + acetochlor7 (28 DAP)
5. PRE + Hand-weed
6. Hand-weed only
1 PRE denotes pendimethalin + flumioxazin applied at planting
Materials & Methods
Herbicide Rates:
2 paraquat (14 DAP) - 0.19 kg AI ha-1 3 paraquat (28 DAP) - 0.29 kg AI ha-1
4 acifluorfen (28 DAP) - 0.28 kg AI ha-1 5 bentazon (28 DAP) - 0.56 kg AI ha-1
6 S-metolachlor (28 DAP) - 0.58 kg AI ha-1 7 acetochlor (28 DAP) - 3.20 kg AI ha-1

10. Materials & Methods
l
Experimental Design: Split-Plot design with 4 replications
Sub-Plot effect: Peanut Cultivar
1. Georgia-06G
2. Georgia-14N
3. TUFRunner™ ‘511’
4. FloRun™ ‘157’ – Plains, GA Only
Data Collected: Visual stunting, visual leaf burn, weed control, & yield (kg/ha).
Weed Species Evaluated: Senna obtusifolia L.(Sicklepod)
Locations: UGA Ponder Farm, TyTy, GA & UGA Southwest REC, Plains, GA.
Data Analysis: PROC GLIMMIX, SAS 9.4
Management: Dryland conditions & according to UGA extension recommendations

11. 2016 Results
It is important to note that there were no interaction
effects. The main effect (herbicides) and the sub-plot
effect (cultivars) were evaluated at an α = 0.05.

12. Leaf Burn - Plains

13. Leaf Burn – Ty Ty

14. Stunting - Plains

15. Stunting – Ty Ty

16. Weed Control - Sicklepod
*Pictures from UGA
Bugwood database
Senna obtusifolia (L.)
• Fabacea family
• Annual
• Common &
Troublesome weed
in peanut fields

17. Weed Control - Sicklepod
Treatment Plains Ty Ty
PRE + par + par 93 ab 93 ab
PRE + par + (a + b) 85 c 93 ab
PRE + par + (a + b) + S-met 95 ab 95 ab
PRE + par + (a + b) + acet 92 b 92 b
The PRE + paraquat + (acifluorfen + bentazon) treatment showed
the lowest amount of control in Plains, Ga.
The PRE + paraquat + (acifluorfen + bentazon) + acetochlor
treatment showed the lowest amount of control in Ty Ty, Ga.

18. Yield (kg/ha)
b
a
ab
a
b
b a aa
a
a a

19. Yield x Cost (Plains, GA)
The red line depicts the price per hectare for each treatment. The blue bars
show the yield per treatment.
Note that with the PRE + par + (a +b) & PRE + par + (a + b) + acet treatments,
the yield is higher than the cost per acre.

20. Plains - Summary
• The bentazon+acifluorfen treatment (B) yielded the highest
(4170 kg ha-1) while the paraquat treatment (A) yielded the
lowest (3250 kg ha-1).
• Cultivars Georgia ‘06G’, Georgia ‘14N’, and TufRunner ‘511’ (3730
kg ha-1 to 4060 kg ha-1) yielded greater than FloRunner ‘157’
(3110 kg ha-1).
• Treatment was significant (p<0.01) to leaf burn and stunting
injury.
• The paraquat treatment (A) resulted in the highest amount of
average leaf burn injury (15%) when compared to the other
treatments (B-D) (5-8%).
• The paraquat treatment (A) resulted in the highest amount of
average stunting injury (20%) when compared to S-metolachlor
(C) (8%) and the other treatments (B & D) (5%).
• In measuring sicklepod control, the bentazon + acifluorfen
treatment (B) produced the lowest amount of average control
(85%) when compared to the other treatments (92-95%).

21. Ty Ty - Summary
• Treatment and cultivars were not significant to the yield.
All treatments yielded between 2960 kg ha-1 and 3340 kg
ha-1 and were not significantly different.
• The paraquat treatment (A) had the greatest amount of
average leaf burn (10%) and average stunting (20%) as
compared to the other treatments.
• The paraquat treatment (A) was significantly (p<0.05)
different than the other treatments.
• The bentazon + acifluorfen treatment (B) resulted in the
lowest amount of average control for sicklepod (85%).

22. Conclusion
The paraquat treatment alone resulted in the lowest
amount of weed control and highest amount of leaf
burn and stunting injury.
This treatment along with FloRunner ‘157’ would
result in the lowest possible yield achievement.
Coupling Georgia 14N or TufRunner ‘511’ with the
bentazon + acifluorfen treatment would produce the
maximum yield while controlling troublesome weeds
and limiting resistance possibilities.

23. Future Research
• Repeat trial in 2017
• Repeat under irrigated conditions
to compare results to this trial
• Evaluate on new cultivars with
different growth characteristics

24. Acknowledgements
- National Peanut Board
- Georgia Peanut Commission
- Georgia Seed Development
Commission
- Dr. Tubbs, Dr. Grey, & Dr. Li
- Chris Cromer, Kristen Pegues,
Hunter Bowen,
Hunter Hayes,
& Sidney Cromer
This project was made possible by: