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

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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?