How to Manage Hard to Control (Escaped) Mid-Season Grasses when
Herbicide Programs Don’t Go As Planned
Barnyard-grass
Amazonsprangletop
Nealley’ssprangletop
Fall panicum
Broadleaf signalgrass
Creepingrivergrass
Brookspaspalum
Water paspalum Knotgrass
Beyond C S S S C S T S S
Bolero + Pro S S S S S T T S S
Clearpath C S S S C T T C S
Clincher C C S C C S T C C
Facet C T T S C T T T T
Grasp C T T T T S T T T
Newpath S S S S C S T C S
Obey C S T S S T T T S
Propanil S S S S S T T S S
RebelEx C* C* S* S* S* S* T S* C*
Regiment C T T T T T T T T
RiceBeaux S S S S S T T S S
RiceStar HT C C C S C S T C C
Strada S T T S T T T T T
C – Control; S – Suppression; T – Tolerant; * Potential for antagonism
Mid-Season Grass Management
Profit over Herbicide Cost vs. Newpath Application Timing
100
150
200
250
300
350
400
450
500
550
Newpath Early fbNewpath 2 WAE
Newpath 1 WAE fbNewpath 3 WAE
Newpath 2 WAE fbNewpath 4 WAE
Newpath 3 WAE fbNewpath 5 WAE
Newpath 4 WAE fbNewpath 6 WAE
$304/A
$198/A$235/A
$186/A
5349
6788
60105916 5922
55955516
6310
5000
5250
5500
5750
6000
6250
6500
6750
7000
NT 1 2 3 4 5 6 WF
Rice Yield following RiceStar HT Timings on Nealley’s Sprangletop
RiceStar HT Application - Weeks after Emergence
lb/A
Nealley’s Sprangletop• Annual • Is often a perennial is south Louisiana • Prolific seed producer• Seed viable at maturity• Not extremely competitive• Must apply herbicides early - Previous slide delaying RiceStar HT
application from 1-6 wk, lose 32 lb/day or 1120 lb/A• Program approach is best• Postemergence 24 oz/A RiceStar HT
Different Propanil Formulations Applied in the Early or Late Newpath Application
2000
3000
4000
5000
6000
7000
No Propanil Stam EC RiceShot EC Stam SC SuperWham Stam EDF
Early LateYield lb/A
Different Propanil Formulations Applied in the Early or Late NewpathApplication, Net returns over Herbicide Costs
400
450
500
550
600
650
700
750
800
No Propanil Stam EC RiceShot EC Stam SC SuperWham Stam EDF
Early Late
$36.5/A
$52.6/A $56.7/A $64.8/A $60.7/A $93.1/A
163%
121%
170%
129%
116%
111%
154%
140%
148%
113%
Residual Herbicides Evaluated
Yield of Clearfield Rice Treated with Residual Herbicides
5000
5200
5400
5600
5800
6000
6200
6400
6600
6800
7000
7200
No Residual Command Facet Grasp Prowl H2O
Ric
e Yi
eld
(lb/A
)
Newpath Beyond
Residual Herbicides Evaluated
Net Returns over Herbicide Cost
600
625
650
675
700
725
750
775
800
825
850
No Residual Command Facet Grasp Prowl H2O
Newpath Beyond
Ret
urns
($/A
) ove
r her
bici
de c
ost
0%
111%
106%
114%
121%122%123%
121%
114%
112%
$14/A $35/A $33/A $11/A
Louisiana Long Grain Rice Acreage as Percent of Total Crop
0
20
40
60
80
100
120
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Conventional ClearfieldC
ypre
ss
Cyp
ress
Coc
odrie
Coc
odrie
Coc
odrie
Coc
odrie
Coc
odrie
Coc
odrie
Che
nier
e
Che
nier
e
CL
151
CL
151
CL
151
Coc
odrie
Che
nier
eC
L 11
1CL
151
Che
nier
e
Che
nier
e
CL
111
Che
nier
eC
L 13
1C
ocod
rieC
L 16
1
CL
121
CL
161
CL
161 C
L 16
1
Che
nier
eC
L 11
1CL
151
Average Rice Yields in Louisiana from 1990 to 2015
4000
4500
5000
5500
6000
6500
7000
7500
310 lb/A550 lb/A
820 lb/A
400 lb/A
1200 lb/A
1910 lb/A970 lb/A
Data from www.nass.usda.gov
Long grain Rice Acreage as Percent of Total Crop vs. Yield Increase
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Conventional ClearfieldC
ypre
ss
Cyp
ress
Coc
odrie
Coc
odrie
Coc
odrie
Coc
odrie
Coc
odrie
Coc
odrie
Che
nier
e
Che
nier
e
CL
151
CL
151
CL
151
Coc
odrie
Che
nier
eC
L 11
1CL
151
Che
nier
e
Che
nier
e
CL
111
Che
nier
eC
L 13
1C
ocod
rieC
L 16
1
CL
121
CL
161
CL
161 C
L 16
1
Che
nier
eC
L 11
1CL
151
4500
5000
5500
6000
6500
7000
7500
• Cutting herbicide rates to save money• Delaying application timing, want to do it one time • Reduced rates often costs more
• Added applications• Reduced control from added applications • Often get into salvage situations – nobody wins• Yield loss due to lack of control
• Realized red rice not eliminated• New/old weed problems you forgot about
Things that Occurred this Year
• A herbicide is not always the best option• Cutting herbicide rates to save money is not a good idea• Nealley’s sprangletop management is not cheap• Apply POST herbicides to small weeds• Know what goes in tank and why• Coverage is important, higher speed, less coverage• Will Provisia rice help? Be prepared to follow stewardship• We have resistance but we can manage it• If you think you have resistance, assume you have it• Rice weed management in Louisiana some of best in last
2-3 years
Conclusion