effects of postemergence herbicides on centipedegrass seed production j. a. ferrell, t. r. murphy,...
TRANSCRIPT
![Page 1: Effects of Postemergence Herbicides on Centipedegrass Seed Production J. A. Ferrell, T. R. Murphy, W. K. Vencill University of Georgia](https://reader035.vdocument.in/reader035/viewer/2022081506/5697bf9c1a28abf838c93617/html5/thumbnails/1.jpg)
Effects of Postemergence Herbicides on Centipedegrass
Seed Production
J. A. Ferrell, T. R. Murphy,
W. K. Vencill
University of Georgia
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Centipedegrass popularity
• Propagated via seed or sod
• Low maintenance– Slow growth– Low nitrogen requirement
• Herbicide tolerance– Sethoxydim and clethodim– Halosulfuron
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Changing Needs
Traditional Emphasis
• Color
• Seedhead Suppression
• Weed Control
Production Emphasis
• Seed Yield
• Seed Quality
• Weed Control
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Digitaria sanguinalis
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Cyperus esculentus
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Objectives
Determine the impact of herbicide and treatment timing on:
• Seedhead suppression
• Seed yield
• Seed quality
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Herbicide Treatments
Herbicides
• Clethodim
• Sethoxydim
• Halosulfuron
Spray Timing
• -4 WPS*• -2 WPS
• 0 WPS (Late July)
• 2 WPS
• 4 WPS
* Weeks post seedhead emergence
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Materials and Methods
• Macon County, Georgia seed farm– Greenville clay loam
• Established centipedegrass (cv. ‘TifBlair’)
• Irrigated, weed-free site
• Plot size – 6’ X 20’
• 3 replications
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Materials and Methods
• Clethodim – 0.25 lb ai A-1 + 0.25% v/v NIS
• Sethoxydim – 0.28 lb ai A-1
• Halosulfuron – 0.062 lb ai A-1 + 0.5% v/v NIS
• 25 GPA, flat fan nozzles, CO2 backpack
• Seedhead suppression –0 to 100 scale• 3 x 5 factorial
• Analysis: herbicide within treatment timing
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Seedhead Suppression
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Seedhead Suppression
Timing Clethodim Sethoxydim Halosulfuron
4 WBS NS NS NS
2 WBS NS NS NS
0 WBS NS
2 WPS NS
4 WPS NS NS NS
NS – non significant
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Seedhead Suppression (0 WPS)
Herbicide 2 WAT 4 WAT
2001 2002 2001 2002
%
Clethodim 50 12 31 0
Sethoxydim 21 3 3 3
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Seedhead Suppression (2 WPS)
Herbicide 2 WAT 4 WAT
2001 2002 2001 2002
%
Clethodim 33 16 23 5
Sethoxydim 18 0 13 0
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Seed Yield
•October 10, 2001
•Harvested 2 randomly selected m2 quadrants
•Seeds removed from heads with mechanical thrasher
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Seed Yield
20
40
60
80
100
120
-4 -2 0 2 4
Weeks Before Seeding
% o
f u
ntr
eate
d
Clethodim
Sethoxydim
Halosulfuron
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Seed Germination
• Conducted by Georgia State Seed Test Lab
• Conditions:– Covered petri dish with moist paper– Temperature – 20 to 35o C– Counts – 7 and 21 days
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Seed Germination
70
80
90
100
110
-4 -2 0 2 4
Weeks Before Seeding
% o
f u
ntr
eate
d
Clethodim
Sethoxydim
Halosulfuron
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Conclusions
• Halosulfuron does not affect centipedegrass seed yield or germination
• Apply clethodim or sethoxydim as early as possible (minimum 4 WBS)
• Once seedheads emerge, use of clethodim or sethoxydim is not advisable
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Future Centipedegrass Research
• Investigate effect of clethodim and sethoxydim in salvage situations (6, 8, 10 WPS)
• Effect of other commonly used herbicides on seed yield and quality
• Develop weed management systems in seedling centipedegrass
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Acknowledgements
• Valent USA
• The Turfgrass Group
• Bill Nutt - technical assistance
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www.bmen.tulane.edu/~mroberts
Any Questions?