Managing Dollar Spot, Anthracnose and
Summer Patch
Bruce B. Clarke, Ph.D.
Extension Specialist in Turfgrass Pathology
School of Environmental and Biological Sciences
Rutgers University
Dollar Spot Disease
• Most common fungal disease of cool-season turfgrasses
• Distributed worldwide, on both warm- and cool-season
turfgrass hosts
• More fungicides used to control/manage dollar spot than any
other fungal disease of turfgrass
The Causal Agent
• Described as Sclerotinia
homoeocarpa by F.T. Bennett in
1937
• True Sclerotinia species produce
fertile apothecia from tuberoid
sclerotia
• The dollar spot pathogen
produces sterile apothecia from
substratal stroma
• DNA sequence data suggests this
pathogen belongs in the
Rutstroemiaceae family
APSNET
Poculum sp. D1172Lambertella viburni CBS 200.47
Poculum sp. D796Poculum sp. D797
Rutstroemia macrospora D1068Poculum sp. D1273Lanzia berggrenii var. metrosideri D1039
Rutstroemia macrospora D2125Ciboria peckiana AK1074
Ciboria peckiana AK1063Ciboria peckiana AK1146Lanzia griseliniae SB118Lanzia allantospora D804Poculum sp. D1295
Rutstroemia sp. SA195
Lambertella subrenispora CBS 811.85 Rutstroemia sydowiana CBS 115975
Sclerotinia echinophila CBS 111549Rutstroemia firma CBS 115.86Rutstroemia firma CBS 341.62
Rutstroemia sydowiana CBS 115928
Sclerotinia homoeocarpa 236935Sclerotinia homoeocarpa PSFFB3
Sclerotinia homoeocarpa CPB17Sclerotinia homoeocarpa 31037Sclerotinia homoeocarpa PSFFB1Sclerotinia homoeocarpa CPB5
Rutstroemia cunicularia CBS 465.73Sclerotinia homoeocarpa 30937Rutstroemia paludosa CBS 464.73Sclerotinia homoeocarpa 236938Sclerotinia homoeocarpa 236941Sclerotinia homoeocarpa SH44Sclerotinia homoeocarpa 51089Sclerotinia homoeocarpa RE18638Sclerotinia homoeocarpa A4Sclerotinia homoeocarpa 235856Sclerotinia homoeocarpa 235854
Sclerotinia homoeocarpa LWC10Lanzia griseliniae D1041Lanzia aureus D1400
Lambertella pruni CBS 199.47Lambertella hicoriae CBS 294.54
Rutstroemia conformata CBS 518.75
Rutstroemia calopus CBS 854.97Sclerotinia homoeocarpa SE16F4Monilinia vaccinii-corymbosi SSI1Monilinia vaccinii-corymbosi SSI2
Ciboria aestivalis CBS 119.47Sclerotinia minor 7440203Sclerotinia sclerotiorum SS5Sclerotinia sclerotiorum SS4Sclerotinia sclerotiorum SS1
1
1
1
0.51
0.92
0.99
1
1
1 10.53
0.86
1
10.75
1
0.57
0.69
1
0.94
0.94
11
11
11
1
0.48
1
1
1
0.53
1
1
Sclerotinia homoeocarpa 31159
0.08
Mcm7 tree
Dollar spot fungus samples
Bennett’s 1937 dollar spot samples
Dollar Spot Taxonomy: Genus Level
• Proposed New Name: Clarireedia
homoeocarpa (F.T. Bennett) Beirn, Clarke,
& Crouch.
• ‘Clarus’ Latin for famous, ‘reedia’ in honor
of Dr.C. Reed Funk, world-renown
plant breeder, turfgrass scientist,
and humanitarian
Dr. C. Reed Funk (1928-2012)
Dollar Spot
Conditions
Favoring
Disease :
Overwinters as Sclerotia /
Mycelium
Resumes Growth at 590 F
Optimum Disease 70 – 840 F
High RH (> 85% Night)
Thick Thatch (> 0.5 – 0.75 in.)
Low Soil Moisture
Extended Dew
Low N Fertility
Cultural Management of Dollar
Spot
Maintain balanced N,P,K fertility
Maintain adequate N when $ spot is active
Light, frequent N applications
Avoid drought stress
Do not irrigate toward dusk
Remove dew by mowing, poling, or rolling
Remove trees to provide good air circulation
Aerify to reduce compaction and thatch
Dragging fairways
Image courtesy Keith Happ
Management of Dollar Spot- continued
Organic fertilizers and composts can reduce dollar spot but this is due more to increased N availability than to
enhanced microbial activity in the soil (Dernoeden, 2003)
Some biocontrol agents have been shown to reduce
dollar spot in the field (Enterobacter cloacae and
Bacillus subtilis)
Microbial products containing Trichoderma harzianum
(Root Shield), Bacillus licheniformis (Ecoguard), and
Pseudomonas aureofaciens strain TX-1 can reduce
dollar spot but often not to commercially acceptable
levels alone
Use new improved bentgrass cultivars whenever possible
Bentgrass Cultivar Classification of Dollar Spot Resistance*
Most Tolerant Moderate Tolerant
Moderate Susceptible
Highly Susceptible
007 Authority Alpha Century
1-3M L-93 Bengal Crenshaw
Benchmk DSR Penn A-1 Backspin Imperial
Declaration Penn A-2 Grand Prix Independence
Kingpin Penncross Mackenzie 18th Green
Pennlinks II Pennlinks Penn A-4
Memorial Seaside PenneagleII
Seaside II Penn G
SR 1150 Princeville
Providence
Southshore
SR 1119
*Table developed from data from NTEP *and bentgrass trials at Rutgers University
18th
Green Declaration
(HTE)
Chemical Control of Dollar Spot
I. Benzimidazoles
Fungo, Cleary 3336
II. Demethylation Inhibitors(Sterol Inhibitors)
Banner, Bayleton,
Eagle, Triton, Trinity,
Torque
III. Dicarboximides
Chipco 26GT
Curalan, Touche, Vorlan
IV. Dithiocarbamates
Fore, Dithane, Pentathlon, Protect
V. Nitriles
Daconil, Echo,
VI. Carboximides
Emerald
VII. QoI’s (Strobilurins) Insignia, Disarm
Compass
VIII. Premixes
Controlling of Dollar Spot on
Putting Greens
Effect of Selected Fungicides on Dollar Spot Development of
a Creeping Bentgrass Green : Rutgers 2009
Treatments applied on 14-day interval beginning on 21 May to 30 July Interface (Iprodione + Trifloxystrobin)
Effect of Selected Fungicides on Turf Quality of a Creeping
Bentgrass Green : Rutgers, 10 August, 2009
Treatments applied on 14-day interval beginning on 271May to 30 JulyTurf Quality 1-9 Scale ( 9 = Best, 5 = Acceptable)
Influence of Fungicides on Dollar Spot (Green) : Rutgers, 2011*
*Fungicides applied from May 24 to August 23
Controlling of Dollar Spot on
Golf Course Fairways
Effect of Selected Fungicides on Dollar Spot Control of a
Creeping Bentgrass Fairway : Rutgers 2010
Treatments applied on 14-day interval beginning on 26 May to 4 August
Dollar Spot Trial 2011: Rutgers UniversityCrenshaw Creeping Bentgrass (Fairway Height)
0
20
40
60
80
100
120
7-Jun 14-Jun 21-Jun 28-Jun 5-Jul 12-Jul 19-Jul 26-Jul 2-Aug 9-Aug 16-Aug 23-Aug
Nu
mb
er
of
Lesi
on
Ce
nte
r/P
lot
Secure (0.5 )* Banner MAXX (1.0) Emerald (0.13)
26GT (2.0) Chlorothalonil 6SC (2.0) UTC
Applications: May 24; June 7, 21; Jul 5, 19; Aug 2, 16.
*Rate per 1,000 ft².
Evaluating Tank Mixtures for
the Control of Dollar Spot
Dollar Spot Trials - 2011 Rutgers University Greens Height Creeping Bentgrass ‘Crenshaw’,
applications made on May 24, June 6 & 21, July 5 & 19.
2012 Dollar Spot Control - Rutgers University
Treatments applied at 14-day intervals starting May 10
1 10 10
7
0 0
54
61
0
10
20
30
40
50
60
70
11-Jun 21-Jul
Do
llar
spo
t le
sio
ns
Dac Action 3.5 fl oz + Appear 3 fl oz
Dac Action 3.5 fl oz + Appear 3 fl oz
Signature 4 oz + Chl 3.6 fl oz
Signature 4 oz + Dac Ultrex 3.2 oz
Untreated
What’s New with Best Management Practices for the Control of Anthracnose
Bruce Clarke and James Murphy
John Inguagiato, Joseph Roberts, Charles Schmid, James Hempfling,
and Ruying Wang
• turf.rutgers.edu (May 2012 GCM)
Anthracnose Symptomology
Acervuli on Infected
Poa annua Tillers
Chlorotic
Leaves
Photo: Landschoot,
APS Press
Cultural Management Strategies
for the Control of Anthracnose
0.141-inch 0.110-inch
31 August 2005
Mowing Height
The Take-Home message is …
… you can significantly reduce anthracnose and
maintain green speed (ball roll distance) by:
(1) increasing heights of cut AND either
(2) increasing mowing frequency, and/or
(3) initiating frequent lightweight rolling
Best Management Practices
Irrigation
Avoid excessively wet or wilt stress
conditions to reduce anthracnose
Irrigate at 80% of ET₀or
60% of ET₀ and timely hand watering to
avoid wilt stress
Best Management Practices
Verti-cutting and other cultivation
CANNOT confirm that wounding from
these practices increases disease
Do not avoid the use of verti-cutting or
other cultivation practices if needed
Best Management Practices
Plant Growth Regulators
Use for better turf and playing quality
They will not increase and may reduce anthracnose severity
1)Proxy (ethephon) or Embark (melfluidide) at label rates during March/April for seedhead control
2)Primo MAXX (trinexapac-ethyl) every 7 to 14 days at 0.1 to 0. 2 fl oz per 1000-ft2 during growing season
Sand Topdressing
Modify thatch/soil
Smooth the surface
Crown protection
Winter protection
Southern Hills CC, Oklahoma
No
Sand
Sand
1 ft3/1000-ft2
2.0 ft3/1000-ft21.0 ft3/1000-ft2No Sand
Topdressing improves surface characteristics
Firmer surface raises effective height of cut
Deeper crowns reducing stress
0
2
4
6
8
10
12
14
0 1 2 3 4 5 6 7
AU
DP
C
Sand L m-2
Anthracnose severity response (AUDPC) to total amount of sand applied (L m-2) during 2009
•1
,00
0 lb
per
1,0
00
ft2
•2
,00
0 lb
per
1,0
00
ft2
Best Management Practices
Nitrogen Fertility – maintain turf vigor
Emphasize Spring N – 1 to 2 lb / 1000-ft2
At higher rates, include slow release
nitrogen
Begin light-frequent N early in the year
(May) at 0.1 to 2 lb of N / 1000 ft2 per wk
Anthracnose severity response to total N applied
on annual bluegrass in 2009, 2010 and 2011
Total N (lb 1000 ft-2
)
0 2 4 6
AU
DP
C
0
10
20
30
40
50
2010
2011
2009
Nitrogen Source & Anthracnose
Recent studies indicate that N Source
affects anthracnose severity
EFFECT OF NITROGEN FORM ON DISEASE SEVERITY
0
20
40
60
80
1-Jun 15-Jun 29-Jun 13-Jul 27-Jul 10-Aug 24-Aug
Dis
eas
e S
eve
rity
(%
)
Date
Potassium Nitrate
Ammonium Sulfate
Ammonium Nitrate
Calcium Nitrate
Urea
Untreated Control*
* Untreated control not included in statistical analysis
2012
Why Does Nitrogen Source Affect?
- N form- Ammoniacal vs. Nitrate - not solely responsible
- Potassium- May help uptake of N
- Stress tolerance
- Soil pH- Ammonium acidifies soil
Potassium can improve winter hardiness and reduce winter injury
Ammonium Sulfate
Potassium Nitrate
Snow Melt / Ice Damage (2011 Rutgers Univ.)
POTASSSIUM SOURCE STUDY 2012
0
10
20
30
40
50
60
1-Jun 15-Jun 29-Jun 13-Jul 27-Jul 10-Aug 24-Aug 7-Sep
Dis
eas
e S
eve
rity
(%
)
Date
N, no K (1:0)
KCl, no N (0:1)
KCl (1:1)
KCl (2:1)
KCl (4:1)
K2SO4 (1:1)
K2SO4 (2:1)
K2SO4 (4:1)
K2CO3 (1:1)
KNO3 (1:1)
First year data
CONVERSION CHART POTASSIUM RATIOS
Elemental ratio Ratio by Wt. Ratio by Wt. Pounds of K2O Pounds of K2O
N : K N : K N : K2O per application* per year *(16 apps)
1 : 1 1 : 2.8 1 : 3.3 0.34 5.38
2 : 1 1 : 1.4 1 : 1.7 0.17 2.69
4 : 1 1 : 0.7 1 : 0.8 0.08 1.34
* Per 1000-ft2
Typical potassium recommendation 1 : 1 (N : K2O by weight)
ANTHRACNOSE POTASSIUM STUDY10 SEPT. 2012
K2SO4 (1:1)
No Potassium
Controlling Anthracnose Basal Rot with
a Sound Fungicide Program
Chemical Control of AnthracnoseI. Demethylation
Inhibitors(Sterol Inhibitors)
Banner, Bayleton,Eagle, Torque, Tourney, Trinity, Triton
II. Strobilurins Heritage, Compass
Insignia, Disarm
III. Antibiotic Endorse, Affirm
IV. Benzimidazoles
Fungo, 3336
V. Nitriles
Daconil, ChloroStar, Echo, Concorde
Combinations (III/IV, I/II, & I/ IV)
ConSyst, Spectro,
Headway, Tartan , Reserve, Renown,
Pillar, Interface, Concert, Disarm C
Efficacy of DMIs on Anthracnose of ABG
Green – Rutgers 2009
% Turf Area Infested
Applied @ 14 day (15 May – 21 Aug)
c
Good Control of ABR until Late August
٠Phosphonate – fosetyl-Al
• Chipco Signature 80WG (4.0 oz)
٠DMI – myclobutanil
• Eagle 40W (1.0 oz)
٠Dicarboximide – iprodione
• Chipco 26GT 2SC (4 fl oz)
٠Phenylpyrrole - fludioxonil
• Medallion 50W (0.25 oz)
◊ Civitas, Daconil Action, Velista?14 – d interval
Evaluating Tank Mixtures for
the Control of Anthracnose
Wong et al (2002) Plant Dis Mgm’t Rpt 1:T064
Applied every 14 days from 15 Jun – 1 Sept
Rated on 24 July
Curative Control of Anthracnose Basal Rot on an
Annual Bluegrass Green – Univ. Riverside, CA
www.turfpathology.ucr.edu
Signature Tank Mix Performance
0
10
20
30
40
50
60
70
2004 2005 2006
An
thra
cn
ose s
everi
ty
Signature 4.0 oz +Daconil Ultrex 3.2 oz
Signature 4.0 oz +Medallion 0.33 oz
Signature 4.0 oz +26 GT 4.0 fl oz
Signature 4.0 oz
Check
a a a
b
a
b
c
d
a a
b
2012 Anthracnose Control - Rutgers University
Treatments applied at 14-day intervals starting May 17; plots evaluated on Sep 2
68.8
5.3
11.316.8
31
20
9.59.36
43.8
63.8
0
10
20
30
40
50
60
70
18-Jun 20-Jul
Anthracnose (%)
Chipco Signature 4 oz +Daconil Ultrex® 3.2 oz
Tartan 2 fl oz
Insignia® 0.7 fl oz
Daconil Action™ 3 fl oz + Briskway™ 0.5 fl oz
Syngenta Program
Untreated
Syngenta Program consisted of tank mixing and alternating with Headway, Daconil Action, Appear, Medallion, Secure, and Briskwayl.lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
A Programmatic Approach to
Controlling Anthracnose Basal Rot
2011 Rutgers University Anthracnose ControlDr. Bruce Clarke
Treatments applied at 14-day intervals starting May 17; plots evaluated on Sep 2
33.3
18.5
613.5
91.5
0102030405060708090
100
Daconil Ultrex3.2 oz
Insignia0.7 fl oz +
Trinity® 1 fl oz
Bayer Program#1
Bayer Program#2
Untreated
% Anthracnose
Bayer Program #1 Signature, Triton FLO, alternated with Signature + Daconil Ultrex; Bayer Program #2 Signature + Triton FLO alternated w/ Signature + Interface
Objective: To determine the effect of best management practices (BMPs) on fungicide efficacy.
Factors:Mowing Height
0.090 vs. 0.125 inch
N Fertility
2.05 vs. 4.1 lb N per 1000 ft2 per yr
Fungicide Program
- Calendar-based 14-day interval at 100%, 75%, 50% and 25% rates of fungicides (3.2 oz/M Dac Ult + 4 oz/M Signature)
- Threshold-based schedule at 100% rate of fungicides
- None
Putting It All Together
BMPs Effect on Fungicide Efficacy -2012
0
5
10
15
20
25
30
35
40
7-Jun 5-Jul 2-Aug 30-Aug 27-Sep 25-Oct
% D
ise
ase
0.090 in
0.125 in
7-Jun 5-Jul 2-Aug 30-Aug 27-Sep 25-Oct
Low N
High N
Fig. 2. Anthracnose severity affected by nitrogen fertilityFig. 1. Anthracnose severity affected by mowing height
N fertility had a greater effect on disease severity
than mowing height.
N fertility interacted with fungicide program, which
means the effectiveness of a fungicide program
depended on the level of N fertility!
50% less fungicide than calendar-based schedule
Low Mow(0.090 in )
High Mow(0.125 in)
Low N(2.05 lbs N 1000 ft-2 yr-1)
9 9
High N(4.1 lbs N 1000 ft-2 yr-1)
5 2
TOTAL # OF FUNGICIDE APPLICATIONS (MAY- SEPT 2012):COMPARISON OF THRESHOLD APPLICATIONS TO COMBINATIONS
OF NITROGEN PROGRAMS AND MOWING HEIGHTS
80% less fungicide than calendar-based schedule10% less fungicide than calendar-based schedule
Summer Patch
Causal Organism :
Magnaporthe poae
Susceptible Hosts :
Annual Bluegrass Poa annua
Kentucky Bluegrass Poa pretensis
Fine Fescue Festuca spp.
Bentgrass Agrostis spp.
Richard Smiley
Conditions Favoring
Summer Patch
Hot, Humid Weather
Excessive Soil Moisture
Low Mowing Height
Soil Compaction / Poor Drainage
Sources of Nitrogen
Urea
Sulfur - Coated Urea
Ammonium Sulfate
Ammonium Chloride
Calcium Nitrate
Potassium Nitrate
Nutralene
Nitroform
Acidification of Soil by Nitrogen Source
4 lb N/1000 sq. ft / year
5 5.5 6 6.5 7
Amm. Sulfate
Amm. Chloride
SCU
Nitroform
Nutralene
Urea
No Nitrogen
Ca. Nitrate
Pot. Nitrate
Summer Patch Management
Aerify and Improve Drainage
Raise Mowing Height during Heat Stress
Overseed with Perennial Ryegrass, Tall Fescue, or Bentgrass
Fertilize with Ammonium Sources, SCU; Avoid using Nitrate Source
Maintain pH at or Below 6.0
Apply Pentrant Fungicides (2 - 4 gal water)
Control of Summer Patch
I DMIs :
- Banner, Bayleton, Eagle,
Trinity, Triton, Tourney, Torque
II Benzimidazoles :
- Cleary 3336
III Strobilurins (QoI):
- Compass, Disarm, Heritage, Insignia
- Headway and Tartan
IV Carboximides: Xzemplar (fluxapyroxad)
Control of Summer Patch on Kentucky
Bluegrass
0
10
20
30
40
50
60
70
80
2-Aug 17-Aug 28-Aug 9-Sep
Rating Date
% D
isease
Banner 2.0 fl oz 14dHeritage 0.2 oz 14dHeritage 0.4 oz 28d
Insignia 0.5 oz 28dAmmonium Sulfate 0.2 lb N onceDaconil Ultrex 3.2 oz 14dUntreated Check
Rutgers 2002
2012 Michigan State University Data, Dr. J. M. VargasTreatments were applied preventively at 96 gallons per acre. Chipco Triton FLO was
applied May 23, June 18 and July 17; other treatments were applied May 23, June 12, July 3 and July 24.
0
10
20
30
40
50
60
5-Jul 10-Jul 15-Jul 20-Jul 25-Jul 30-Jul 4-Aug 9-Aug 14-Aug 19-Aug 24-Aug
Sum
me
r p
atch
se
veri
ty (
%)
Untreated
Triton FLO 0.75 fl oz
Banner MAXX® II 1 fl oz
Heritage® TL 1 fl oz
Effect of Fungicides on Summer Patch – Kentucky Bluegrass :
Rutgers, 2011*
*Fungicides applied from May 27 to August 15, every 14 d
Dis
ease
sev
erit
y i
nd
ex /
plo
t
Summer Patch Chemical Control
DMIs, Benzimidazoles, Strobilurins,
and certain Carboximides
Use full label rates – 3 times / season in
areas with a history of summer patch
Apply in 2 - 4 gal water / 1000 ft2 or
Irrigate mmediately after spraying
Timing – Soil temp. 65o F @ 2” depth for 5
to 7 consecutive days
Thank you for your attention!
Questions?
Top Related