Advanced Weed Control for Athletic Field Turf

1/9/2015
Advanced Weed Control for Athletic Field Turf
Outline
•
•
•
•
I. What is Properly Managed Turf?
II. Preemergence Herbicides
III. Postemergence Herbicides
IV. Herbicide Resistance Management
Gerald Henry, PhD – University of Georgia
Jared Hoyle, PhD – Kansas State University
Maintaining Healthy Turf
•
•
•
•
•
•
Reduced Light Intensity
Select the right turfgrass species/cultivar
Proper irrigation
Correct mowing height and frequency
Adequate fertility
Cultivation practices
Using weeds as indicators
Selecting the Right Grass
Photo: Jim Brosnan, UT
More than Herbicides Are Needed Here
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‘TifGrand’ Hybrid
Bermudagrass
Hong Kong Gov. Stadium
Use regional NTEP data
Irrigation
Irrigation
• Amount:
– Varies with grass species (rooting, etc.), soil type, and environmental conditions (evapotranspiration)
• Frequency:
– Varies with local conditions
– Standard rule: apply water deeply and infrequently
• Time of day:
– Early morning hours are best ‐ evaporative loss is less and turf is allowed to dry
Irrigation Frequency
Mowing
Frequent
Infrequent and Deep
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Mowing Height
• Each species has its mowing tolerance range • Below this range: – Turf will thin or be overtaken by weeds
• Above this range:
Above this range:
– Increased disease pressure
– Puffiness
Clippings
Mowing Frequency
• Every 5 to 7 days
• Lower height = ↑ frequency
• Rules:
– Never remove > 1/3 leaf /
tissue per mowing
– Avoid mid‐day mowing when heat stress occurs
Effect of Mowing Height on Crabgrass
• Contribute little to thatch
• Can be safely returned if turf is mowed regularly
• Returned clippings can contribute 2 lbs
d li i
ib
2 lb
N/1000 ft2/year in addition to other nutrients
• Clipping removal may reduce weed seed
– Annual bluegrass
Tall Fescue – 4 inch % Crabgras
ss Cover
Effect of Mowing Height on Crabgrass Incidence in Tall Fescue
Hoyle et al. 2009
Tall Fescue – 1 inch
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Mowing to Reduce Weed Colonization
• Mowing depletes carbohydrate reserves through biomass reduction
• Mowing depletes carbohydrate reserves through biomass reduction
Bahiagrass &
Dallisgrass
Mowing Heights (in.)
0.5, 2, 3, and
non-mowed
Henry et al. 2007
Rhizome Weight ((g)
Mowing to Reduce Weed Colonization
Bahiagrass Rhizome Weight (g)
350
300
250
0.5 inch
200
2.0 inch
150
3.0 inch
100
Non‐mowed
50
0
0.5 inch
2.0 inch
3.0 inch
Non‐mowed
N Fertility Programs
• Cool‐season grasses (KBG)
Fertility
Cool‐Season N Program
Timing
Nitrogen (lb N/1000 ft2)
March/April
0.5 – 0.75
May/June
0.5 – 0.75
June/July
0
August
1.0
September
1.0
Late Fall
1.0 – 1.5
– Rates will vary with environmental conditions and soil type
– Lighter N applications in the spring
– Heavier N applications in the fall
– Minimize N applications in the summer
– Fe can be applied for green up
N Fertility Programs
• Warm‐season grasses (Bermudagrass)
– Rates will vary with environmental conditions and soil type
– 1.0 lb N/1000 ft2 is recommended per growing month
– No more than ½ lb N in September to minimize Spring Dead Spot
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Excessive Nitrogen Fertilization
↑ Shoot Growth
Extensive Roots
Cultivation
Cultivation
• Aerification/Verticutting
• Alleviate thatch and soil compaction
– Enhance rooting
E h
ti
– Increase water infiltration
– Increase gas exchange
– Decrease nutrient deficiencies
What are your weeds telling you?
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Weeds as Indicators
• Soil Compaction
– Associated with high traffic, poor water infiltration, etc.
– Presence of prostrate knotweed, goosegrass, annual bluegrass, prostrate spurge, broadleaf plantain, khakiweed, etc.
Weeds as Indicators
• Low Soil Nitrogen Fertility
– Associated with low fertility inputs, sandy soil, etc.
– Presence of clover spp., black medic, common lespedeza, corn speedwell, hawkweed, etc.
Weeds as Indicators
• Wet/Saturated soils
– Associated with poor water infiltration, heavy clay soils, low‐lying areas
– Presence of sedge spp., annual bluegrass, goosegrass, mosses, etc.
Photo: Pete Landschoot, PSU
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Weeds as Indicators
• Low soil pH – red sorrel
• High soil pH – plantains
• Droughty soils –
g y
prostrate spurge, black p
p g ,
medic, knotweed, yellow woodsorrel
• High soil N – annual bluegrass, chickweeds, moss
• Low mowing height – algae, annual bluegrass, moss, chickweeds Preemergence
Herbicides
Preemergence Herbicides
Application Timing
Summer Annuals
Herbicides do not prevent weeds from
germinating, they control weeds as they
grow through the herbicide treated zone
Spring
Winter Annuals
Summer
Fall
Winter
Preemergence Weed Control
• Target species: annual grasses; annual and some perennial broadleaf weeds
• Spring applications
– Initial app. late February to mid‐March
I iti l
l t F b
t
id M h
– Sequential app. approx. 60 days later
• Fall applications
– Mid to late September
Application Technique is Critical
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Preemergence Herbicides
Large gaps in herbicide barriers result in weed escapes
Preemergence Herbicides
Preemergence Herbicides
• More important than ever
• Provide annual grassy weed control ‐
crabgrass, goosegrass, annual bluegrass, etc.
• Preemergence herbicides:
Herbicides do not prevent weeds from germinating, they control weeds as they grow through the herbicide treated zone
– prodiamine (Barricade)
– dithiopyr (Dimension)
– pendimethalin (Pendulum)
– oxadiazon (Ronstar)
– oryzalin (Surflan)*
*Not labeled for use on Kentucky bluegrass
Specticle
Launched in 2010
Active Ingredient – Indaziflam
Chemical Class: Alkylazines
Warm‐season
Warm
season turf tolerance
turf tolerance
Excellent activity on annual bluegrass, crabgrass spp., goosegrass, and broadleaf weeds
• Low application rate
• Long soil residual
• Root absorbed only
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•
•
•
•
4.5 M 5.5 M
UT – J. Brosnan
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Perennial Ryegrass Cover
Specticle
– Ryegrass overseeding
Ryegrass overseeding safety
– Recovery from wear/traffic, stress, and damage
• Spring dead spot disease
32 WAIT
% ryegrass co
over
• Not a good fit for Athletic Field turf!
• Long soil residual/”root pruning” damage
WAIT = Weeks After Initial Treatment
Specticle
DNA Herbicides
Photo: J. Brosnan, UT
Preemergence Herbicides
• Dinitroanalines (DNAs):
– Prodiamine (Barricade, Quali‐Pro Prodiamine)
– Oryzalin (Surflan, Quali
(Surflan, Quali‐Pro
Pro Oryzalin)
Oryzalin)*
– Pendimethalin (Pendulum, Pre‐M, etc.)
– Oryzalin + benefin (XL)*
Rooting/Recovery Concerns
“Root Pruning” Damage
• Warm‐season turf issue – stoloniferous grasses
• Herbicides are predominantly root absorbed
*Not labeled for use on Kentucky bluegrass
Photo: J. Brosnan, U Tenn
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Photo – A. Patton
Preemergence Herbicides
• Oxadiazon (Ronstar, Quali‐Pro Oxadiazon)*
• Predominantly shoot absorbed
• Dithiopyr (Dimension, Quali‐Pro Dithiopyr)
• May cause similar damage to roots as DNA herbicides
*Can be applied safely in the Spring to grasses seeded in the Fall
Swollen roots on a bermudagrass stolon growing into soil where a preemergence herbicide was applied
Bermudagrass Recovery from Spring Dead Spot in
from Spring Dead Spot in Response to Preemergence
Herbicides
% SDS Reco
overy
Bermudagrass Recovery ‐ 2012
Recovery from 4/10 to 6/25
Untreated Check
6/25/2012
Ronstar ‐ Oxadiazon
6/25/2012
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Specticle ‐ Indaziflam
Tower
Active Ingredient – Dimethenamid
Safe on warm and cool‐season turf
Use on established turf
Preemergence broadleaf, grass, and sedge weed control
• Predominantly shoot absorbed
• Freehand* = dimethenamid + pendimethalin
•
•
•
•
6/25/2012
*No cool‐season turf tolerance
Large Crabgrass Control – 21 WAIT
Pendulum – 4.2 pt/A
% Crabgrass Cover
fb Tower – 32 fl oz/A
80
Untreated Check
70
Pendulum fb Tower
60
Tower fb Tower
50
Tower fb Tower fb Tower
fb
fb
40
Freehand fb Freehand ‐
low
Freehand fb Freehand ‐
high
Drive + Tower
30
20
10
Barricade fb Barricade
0
Herbicide Treatments
Sept. 15, 2011
Generic vs. Name Brand
Preemergence Large Crabgrass Control
% Contrrol
5 MAIT
100
80
60
40
20
0
Annual Grass Weed Control
Annual Grass Weed Control
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Crabgrass/Goosegrass Control
• Apply preemergence herbicides in the spring when daytime temperatures reach 65 F for four or more days
• Materials must be watered in (1/2 inch) Materials must be watered in (1/2 inch)
within 7 days after treatment in order to activate the herbicides
Kentucky Bluegrass
Preemergence Herbicides
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•
Benefin (Balan)
Benefin + Trifluralin (Team Pro)
Dithiopyr (Dimension)
Mesotrione (Tenacity) – crabgrass only
Oxadiazon (Ronstar)
Pendimethalin (Pendulum)
Prodiamine (Barricade)
Siduron (Tupersan)
Non‐overseeded Bermudagrass
•
•
•
•
•
•
•
•
•
•
•
Benefin (Balan)
Preemergence
Benefin + Oryzalin (XL)
Herbicides
Benefin + Trifluralin (Team Pro)
Bensulide (Bensumec)
g
/
g
Bensulide + Oxadiazon ((Scott’s Goosegrass/Crabgrass Control)
Dithiopyr (Dimension)
Metolachlor (Pennant)
Oryzalin (Surflan)
Oxadiazon (Ronstar)
Pendimethalin (Pendulum)
Prodiamine (Barricade)
Annual Bluegrass Control
• Apply in late summer – August/September
• Materials must be watered in (1/2 inch) within 7 days after treatment in order to activate the herbicides
activate the herbicides
• Most herbicides labeled for preemergence
control of crabgrass/goosegrass effectively control annual bluegrass
Preemergence Herbicides
Annual Grass Control in Overseeded Bermudagrass
• Balan 2.5G (benefin) – 120 lbs/A
–6 to 8 WBO fb 6 WAO
• Dimension 40WP (dithiopyr) –
(
py ) 1.25 lbs/A
/
–8 WBO
• Barricade 65WG (prodiamine) – 0.38 to 0.75 lbs/A
–8 WBO fb 4 WAO
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Preemergence Herbicides
• Pendulum 60 WDG (pendimethalin) –
3.4 lbs/A
–12 WBO
• Ronstar 2G (oxadiazon) – 100 lbs/A
–16 WBO
Postemergence
Herbicides
Only Provide Fair Control
New Chemistries
Celsius
• Formulation: 68 WG
• Active Ingredients:
– Thiencarbazone
– Iodosulfuron
– Dicamba
• Rate: 2.5 to 7.4 oz/A
• Tolerant Turf Species: bermudagrass
• Target Weeds: POST annual and perennial broadleaf weeds and grasses
Carpetgrass Control
% Conttrol
% Control
Virginia Buttonweed Control
Initial apps. made in July
Initial apps. made in July
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Dallisgrass Control – 37 WAIT
Tribute Total
Rating - June 2011
– Thiencarbazone
– Foramsulfuron
– Halosulfuron
• Rate: 3.2 oz/A
• Tolerant Turf Species: bermudagrass
• Target Weeds: POST sedge, broadleaf weeds, cool‐season grasses, large crabgrass, goosegrass, dallisgrass
% Controll
• Formulation: 60.5 WG
• Active Ingredients:
Tribute Total – 3.2 oz/A – Sept – 37 WAIT
Tropical Signalgrass Control Spot Spray
App. #
% Control
May 5th
June 9th
94
96
3
3x
98
96
4x
100
98
5x
100
100
2x
Trts: Sept. 23; Oct. 7, 21; and Nov. 4 and/or 18. – 0.073 oz Tribute Total/gal water 6/6/2011
McCarty and Estes – GCM Magazine, Sept. 2014
Tribute Total Overseeding Safety
Tribute Total Overseeding Safety
• Tribute Total – 3.2 oz/A
– Applied 8, 6, 4, and 2 WBO
• Perennial ryegrass overseeding
– 8 lbs/1000 ft2 – Oct.
• Evaluated ryegrass cover in mid‐December
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Ryegrass Overseeding Safety
Blindside
% Ryegrasss Cover
• Formulation: 66 WG
• Active Ingredients:
– Sulfentrazone
– Metsulfuron
• Rate: 3.25 to 10 oz/A
• Tolerant Turf Species: bermudagrass and Kentucky bluegrass
• Target Weeds: POST grasses, sedges, and broadleaf weeds
Ground Ivy Control
Khakiweed Control
Blindside – 8 WAT
Blindside – 12 WAIT
SquareOne
• Launched in 2011
• Active Ingredients:
– Carfentrazone
– Quinclorac
Q i l
• Rate: 8 to 18 oz/A
• Tolerant Turf Species: bermudagrass, Kentucky bluegrass, perennial ryegrass
• Broadleaf, sedge, and grassy weed control
• Fast activity
Defendor
• Launched in 2013
• Active Ingredient:
– florasulam
• Turf Tolerant Species: bermudagrass, p
g
,
Kentucky bluegrass, perennial ryegrass, tall fescue
• Target Weeds: annual and perennial blws
• Defendor packaged with Dimension 2EW for early spring dandelion control (Purdue)
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Symptomology from florasulam
Purdue University – April 2, 2012
Photo: A. Patton, Purdue
Photo: A. Patton, Purdue
Dimension 2EW + florasulam applied March 16
Dandelion Control
Photo: A. Patton, Purdue
40
a
% Dandelion cover
35
ab
30
25
20
15
10
abc
cd
cd
e
de
e
e
5
0
100% bloom reduction when applied 2 wks before flowering
Defendor Use Tips
• Early application at least 2 weeks prior to bloom
• Sequential applications to improve control
• Best results
l
– follow first application of Dimension + Defendor
with a broadleaf herbicide (like Triplet or Trimec) after regrowth
A. Patton, Purdue
Defendor Summary
• Fall BDLV herbicide apps work well to control perennials
• Defendor does something unique ‐ keeps dandelions from flowering when applied in early spring
• Timing is early with spring PRE herbicides as a tank‐mix g
g
targeted for crabgrass control
• Defendor’s strength is early season “control” and bloom suppression
• Utility in LCO market
– Reduces call‐backs
– Will delay application of phenoxy herbicides in spring until better conditions for control exist
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Bleaching Pylex
• Greatest bleaching observed during active turfgrass growth periods – spring and fall for cool‐season turf. Less bleaching seen during summer months when turf is growing less • Addition of Turflon® ester and Drive® XLR8 herbicide to Pylex results in a significant reduction in bleaching
• The addition of Turflon and Drive XLR8 act to slow down growth of the target weed resulting in less bleaching
• Launched in 2013
• Active Ingredient:
– Topramazone
• Bleaching herbicide (HPPD inhibitor)
• Turf
Turf Tolerant Species:
Tolerant Species: Kentucky bluegrass, Kentucky bluegrass,
perennial ryegrass, tall fescue
• Bermudagrass and goosegrass control in cool‐
season turf
• Spot spray only for athletic fields
– 1 to 1.5 fl oz/A
98
Tompramazone (14 DAA) Not Treated
Pylex
Turflon
Pylex + Turflon
Goosegrass control: Trts made on July 21 and
August 11 to tillered goosegrass. VT, 2012
Uses • Bermudagrass control
– multiple apps required late summer with Turflon
(triclopyr)
100
90
• Goosegrass control
80
70
% Controll
– tank mix with Drive® or Onetime® to enhance crabgrass control
• Nimblewill or crabgrass control – Pendulum® can be tank mixed for residual crabgrass control
• Weed control at time of seeding
Pylex herbicide 1.5 oz 2
app
60
50
Pylex herbicide 1.5 +
Turflon 32 oz 2 app
40
30
Tenacity 8 oz 2 app
20
10
0
1‐Aug
101
1‐Sep
102
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Comparing Pylex vs. Tenacity
• Pylex herbicide
• Tenacity herbicide
– Very good on bermudagrass
– Excellent on goosegrass
– Better on dandelion
– Weaker on bermudagrass and g
goosegrass
g
– Safer to more grasses – No spot spray restriction
– Poa annua is sensitive
– Moderate activity on nutsedge
Difficult to Control Weeds
Difficult to Control Weeds
• Similar on most broadleaves
• Similar on crabgrass and nimblewill
Controlling Sedge Spp.
Controlling Sedge Spp.
Yellow Nutsedge
Yellow Nutsedge
Yellow Nutsedge
Yellow Nutsedge
• Postemergence Herbicide Options:
– Halosulfuron (Sedgehammer)
• Safe on bermudagrass, Kentucky bluegrass, and perennial ryegrass
and perennial ryegrass
– Imazaquin (Image)
• Safe on bermudagrass
– Sulfosulfuron (Certainty)
• Safe on bermudagrass
• Postemergence Herbicide Options:
– Trifloxysulfuron (Monument)
• Safe on bermudagrass
– Bentazon (Basagran)
(
)
• Safe on bermudagrass, Kentucky bluegrass, and perennial ryegrass
– Sulfentrazone (Dismiss)
• Safe on bermudagrass, Kentucky bluegrass, and perennial ryegrass
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Yellow Nutsedge
• Postemergence Herbicide Options:
– Sulfentrazone + Imazethapyr (Dismiss South)
Yellow Nutsedge Control in Bermudagrass
• Treatments:
– Sedgehammer (1.3 oz/A) applied once or twice
– MSMA (1 oz/1000 ft2) applied once
– MSMA (1 oz/1000 ft
MSMA (1 oz/1000 ft2) + Image (1.3 pt/A) applied ) + Image (1 3 pt/A) applied
once
– Monument (0.53 oz/A) applied once or twice
• Safe on bermudagrass
– Mesotrione (Tenacity)
(
)
• Safe on Kentucky bluegrass and perennial ryegrass
Yellow Nutsedge Control in Bermudagrass
% control
Yellow Nutsedge Control in Bermudagrass
Application dates: May 13, May 26 (MSMA), and Jun 23
Application Timings: July 15, 2009 and August 12, 2009
Sulfentrazone 4 WAT – Aug 4
Purple Nutsedge
p
g
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Purple Nutsedge
Purple Nutsedge
• Tubers linked by chains of rhizomes • Postemergence Herbicide Options:
– Trifloxysulfuron (Monument)
• Safe on bermudagrass
– Sulfosulfuron (Certainty)
(
)
• Safe on bermudagrass
– Sulfentrazone + Imazethapyr (Dismiss South)
• Safe on bermudagrass
Purple Nutsedge
• Postemergence Herbicide Options:
– Imazaquin (Image)
Purple Nutsedge Control in Common Bermudagrass
fl oz or oz/A
• Safety on bermudagrass
– Sulfentrazone (Dismiss)
• Safe on bermudagrass, Kentucky bluegrass, and perennial ryegrass
– Halosulfuron (Sedgehammer)
• Safe on bermudagrass, Kentucky bluegrass, and perennial ryegrass
WAIT = Weeks After Initial Treatment
Certainty – 12 WAIT
Dismiss South – 12 WAIT
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Purple Nutsedge Control with Dismiss
Dallisgrass
Application date: 6/15/2008
Dallisgrass Control ‐ TX
• September Application
– Tribute Total – 2 or 3.2 oz/A + MSO + AMS
• October Application
– Tribute Total Tribute Total – 2 or 3.2 oz/A + MSO + AMS
2 or 3 2 oz/A + MSO + AMS
• Sept fb Oct Application
Results – 37 WAIT
Results 37 WAIT
– Tribute Total – 2 or 3.2 oz/A + MSO + AMS
– Foramsulfuron – 64 fl oz/A
– Dicamba + Iodosulfuron + Thiencarbazone
(Celsius) – 3.6 oz/A + foramsulfuron – 64 fl oz/A
Dallisgrass Control – 37 WAIT
Untreated Check – 37 WAIT
% Controll
Rating - June 2011
6/6/2011
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Tribute Total – 3.2 oz/A – Sept – 37 WAIT
Tribute Total – 3.2 oz/A ‐ Oct – 37 WAIT
6/6/2011
6/6/2011
Cultural + Chemical Control
Dallisgrass Control
• Initial app. – June 14, 2013
• Sequential app. – Aug. 28, 2013
• Herbicide treatments (app. to verticut and non‐verticut):
i )
• Location: Pine Hills GC, Winder, GA
• Trial site was mowed 48 hrs
before study initiation
• Half the site was verticut
two directions – 1 in. depth
• Entire area was raked of debris
–
–
–
–
Dallisgrass Control – 8 WAIT
Before
% Conttrol
2nd App.
Tribute Total – 3.2 oz/A
Celsius – 3.6 oz/A + Revolver – 64 fl oz/A
MSMA – 44 fl oz/A
Certainty – 1.25 oz/A + MSMA – 44 fl oz/A Dallisgrass Control with Pylex
• Option A:
– 3 apps. (1 to 1.3 fl oz/A) 3 ‐ 4 weeks apart
– 1st app. mid‐to‐late summer
• Option B:
– 2 apps. (1.5 fl oz/A) 3 ‐ 4 weeks apart
– 1st app. late summer
Initial apps. made in June
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Crabgrass/Goosegrass
• Typically apply during the months of June and July
Crabgrass/Goosegrass
– Sequential applications may be necessary
• Target immature plants
Target immature plants
– Especially important with goosegrass control
Crabgrass/Goosegrass Control
• Postemergence Herbicide Options:
– Quinclorac (Drive XLR8) – crabgrass only
• Safe on bermudagrass, Kentucky bluegrass, and perennial ryegrass
• Can be applied at overseeding and 28 days after
• Formulated mixtures –
–
–
–
–
Crabgrass/Goosegrass Control
• Postemergence Herbicide Options:
– Fenoxaprop (Acclaim Extra) • Safe on Kentucky bluegrass
quinclorac + sulfentrazone (Solitaire)
quinclorac + sulfentrazone + 2,4‐D + dicamba (Q4 Plus)
quinclorac + 2,4‐D + dicamba (Quincept)
quinclorac + dicamba + MCPP (Onetime)
quinclorac + carfentrazone (Square One)
Mature Large Crabgrass ‐ UGA
• Application time –
July 16, 2012
• Site – mature large crabgrass (multi
crabgrass (multi‐
tillered) maintained at 2 inches
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Herbicide Treatments
Untreated Check – 4 WAT
• Drive XLR8 (64 fl oz/A) + MSO (0.5% v/v)
• Tribute Total (3.2 oz/A) + MSO
• Acclaim Extra (13 oz/A) + NIS (0.25% v/v) + Dimension (0.5 pts/A)
i
i (0
/A)
• Acclaim Extra (20 oz/A) + NIS + Dimension (0.25 pts/A)
• Acclaim Extra (28 oz/A) + NIS Drive XLR8 + MSO – 4 WAT
64 fl oz/A
Crabgrass/Goosegrass Control
• Postemergence Herbicide Options:
– Mesotrione (Tenacity)
• Safe on dormant bermudagrass, Kentucky bluegrass, and perennial ryegrass
– Topramezone (Pylex)
• Safe on Kentucky bluegrass and perennial ryegrass
• Spot spray at 1 to 1.5 fl oz/A
Tribute Total + MSO – 4 WAT
3.2 oz/A
Crabgrass/Goosegrass Control
• Postemergence Herbicide Options:
– Prodiamine + Sulfentrazone (Echelon)
• Safe on bermudagrass, Kentucky bluegrass, and perennial ryegrass
• Early POST control of seedling crabgrass but mainly PRE activity
– Foramsulfuron (Revolver) – goosegrass only
• Safe on bermudagrass
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Khakiweed
% Conttrol
Sequential Apps. for Khakiweed Control
100
90
80
70
60
50
40
30
20
10
0
Speedzone Southern (1x)
Celsius
4Speed XT
Imprelis
Initial app. – 6/1/2010
Pend Aquacap + Onetime
d
i
Pend + BAS 8004H
Pend + Drive XLR8
Blade 0.5 oz
Blade 1.0 oz
Monument 0.35 oz
8 WAIT
Monument 0.53 oz
Sequential apps. made 3 to 5 WAIT
Blade – 0.5 oz/A – 8 WAIT
Monument – 0.35 oz/A – 8 WAIT
Celsius – 0.085 oz/1000 ft2 – 8 WAIT
4Speed XT – 1.1 fl oz/1000 ft2 – 8 WAIT
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Annual Bluegrass Control in Overseeded Bermudagrass
• Postemergence Herbicide Options:
– Foramsulfuron (Revolver) • Apply up to 1 week before overseeding
– Rimsulfuron (TranXit)
• Apply up to 10 to 14 days before overseeding
Annual Bluegrass Control in Overseeded Bermudagrass
• Postemergence Herbicide Options:
– Flazasulfuron (Katana)
• Apply up to 2 to 4 weeks before overseeding
• Control enhanced with addition of urea
– Trifloxysulfuron (Monument)
• Apply up to 3 weeks before overseeding
Annual Bluegrass Control in Overseeded Bermudagrass
• Postemergence Herbicide Options:
– Ethofumesate (Prograss)
• Two apps. in late fall to early winter after overseeding
di
• 1st app. late November with a sequential 3 weeks later
Herbicide Resistance Management
– Bispyribac Sodium (Velocity)
• Two apps. in the spring after overseeding in fall
• 1st app. in late winter/early spring Photo: J. Brosnan ‐ UT
What is herbicide resistance?
• “The ability of a plant to survive and reproduce following exposure to a dose of herbicide normally lethal to the wild type”
Vencill et al. 2012. Weed Science
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Understanding Resistance
• Weeds do not change or mutate to become resistant
• A few weeds may survive exposure to an herbicide due to their genetic makeup
herbicide due to their genetic makeup • When those weeds that survive breed, some of their offspring will inherit the genetic trait that confers resistance
Understanding Resistance
• These weeds will not be affected the next time a similar herbicide is used
• If the same herbicide is applied often, the proportion of less susceptible individuals in
proportion of less‐susceptible individuals in the population will increase
Understanding Resistance
• Higher rates and more frequent applications of the herbicide are often used until eventually the pesticide provides little or no control
• At this point, the population has become resistant….
Why does it happen?
•
•
•
•
•
Herbicide tolerant cropping systems
Lack of diversified weed management
Same Modes of Action (MOA)
Lack of cultural weed management
Weeds have short life cycles, wide geographic ranges, and large populations
– Substantial genetic diversity
Why does it matter?
Herbicide Resistance
• Increased cost to control weeds
• Lost revenue
• Lost herbicidal MOAs
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1/9/2015
Case Studies
Case Studies
Dr. Jim Brosnan, UT
Dinitroanaline Resistance
• Cases of DNA resistance reported in NC and TN
• Two new reports in TN in spring of 2012
Prodiamine (Barricade)
•
•
•
•
Dinitroaniline (DNA)
Mitotic inhibitor
Root absorbed/active
/
Used for PRE control of annual grasses and some broadleaf weeds
Lambert Acres Golf Club
• Maryville‐Alcoa, TN
• Roundup (32 fl oz/A) + Barricade (0.75 lb
ai/A)
• Applied for 10 consecutive years
• No annual bluegrass control reported in 2011
Root growth of
prodiamine
resistant (PR) and
susceptible (SS)
annual bluegrass
in Alcoa, TN
0
0.41
4.1 41 410 4100
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1/9/2015
Biotype is Cross-Resistant to Glyphosate
DNAs = Seedling Root Inhibitors
Susceptible
Resistant
Prodiamine Resistant Goosegrass
Resistant
Root growth after
prodiamine at 1.0 mM
Root growth after
prodiamine at 0.001mM
Susceptible
Root growth after
prodiamine at 1.0 mM
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1/9/2015
What is effective on mature goosegrass POST?
J.T. Brosnan, Ph.D.
University of Tennessee
PR Goosegrass Control with Pylex
•
•
•
•
•
•
Topramezone
HPPD inhibitor
J.T. Brosnan, Ph.D.
Grassy weed control
University of Tennessee
Cool-season grasses
Rates of 0.5 to 2.0 fl oz/A with MSO surfactant
Yearly max at 4 fl oz/A
Goosegrass Co
ontrol (%)
Pylex
Multi‐tillered Plants
100
Pylex+MSO
(0.5 fl oz)
Pylex+MSO
(0.75 fl oz)
Pylex+MSO
(1 fl oz)
Revolver
(17.4 fl oz)
Revolver
(26.2 fl oz)
75
50
25
0
14 DAT 28 DAT 50 DAT
Untreated Check
Pylex (1 fl oz) + MSO ‐ 50 DAT Bermudagrass Injury
Quicker Recovery with Late Summer Apps
Late Summer Apps.
J.T. Brosnan, Ph.D.
University of Tennessee
30
1/9/2015
Options?
It’s not just g
a single product
• Oxadiazon program
• Increased $$
• What do you rotate to from oxadiazon?
p
• No post winter annual
• Tank mix with glufosinate? (access, $$)
• Specticle program
• Increased $$
• Rotation with oxadiazon?
• Traffic recovery issues?
Options?
• ALS or Simazine Programs
• $$
• No residual for summer annuals
Resistance is out there
• Resistance is out there
ALS Inhibitors for POST Poa
POST Poa
Control
Acetolactate Synthase Inhibitors
• Branched chain amino acids
• Low use rates, low mammalian toxicity
• Used for cool‐season grass control in warm‐season turf
• Several golf courses report poor annual bluegrass control in 2012
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1/9/2015
Red = Resistant
Red = Resistant
0 oz
0.06
oz
0.13
oz
0.26
oz
0.53
oz
1.06
oz
4.24
oz
2.12
oz
ALS Resistant POAN 28 DAT with Trifloxysulfuron
139
oz
0 oz
ALS Resistant POAN 28 DAT with Foramsulfuron
Trifloxysulfuron at 4.24 oz/A + NIS at 21 DAT
Resistant
ab
b
b
ab ab
Susceptible
ab
c
bc bc
cdef
cdefg
cdefgdefg
efg
Resistant POAN Control 21 DAT
Options?
ALS Inhibitors for POST Poa
POST Poa
Control
• Move to a PRE program
– MOA mixtures/rotation
– Specticle, Ronstar
• Experiment with glyphosate POST
• Hope for new MOA?
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1/9/2015
Prevention and Management
Prevention and Management
• Proper Turfgrass Management
Prevention and Management
• Proper Turfgrass Management
• Scout for Weed Escapes
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1/9/2015
Prevention and Management
•
•
•
•
Modeled Effects of Rotation on Triazine Resistance
Proper Turfgrass Management
Scout for Weed Escapes
Site Specific Management
Herbicide Rotation/Tank Mixtures
Modeled Effects of Rotation/Mixtures on ALS Resistance
100.0
40.0
Risk of Deve
eloping Resistance in 30 years
Years to develop resistance (30%)
• Proper Turfgrass Management
• Scout for Weed Escapes
• Site Specific Management
Prevention and Management
30.0
20 0
20.0
10.0
0.0
No rotation
2 on : 1 off
1 on: 1 off
1 on : 2 off
75.0
50.0
25.0
0.0
No rotation
ALS + quinclorac
HPPD fb ALS
ALS fb ACCase
*Assumes rate for 95% control, 2 yr seed life, fitness = 1
Resistance (20%) observed within 4 years with ALS only program
Gressel and Segel. 1990. Weed Technol. 4:186‐198
Bagavathiannan et al. 2014. Weed Tech. 28:89‐103
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1/9/2015
Gerald Henry, PhD
gmhenry@uga.edu @UGATurfgrass
Jared Hoyle, PhD
jahoyle@ksu.edu
@KSUTurf
Q
Questions?
i ?
35