Amy M. Baetsen|| Dr. John E. KaminskiThe Pennsylvania State University

Thatch Collapse: A New Disease of Golf Course Turf

THATCH COLLAPSE• First Identified on Fine Leaf Fescue in

Northern Scotland Summer 2010– May 2011 Issue of Golf Course Management

• Symptoms Observed at Penn State Research Facility Fall 2010

THATCH COLLAPSE• Believed to be Caused by a Basidiomycete

OVERVIEW OF BASIDIOMYCETES• Yellow Ring (Trechispora alnicola)

– Kentucky Bluegrass • Superficial Fairy Ring (T. cohaerens and

Coprinus kubickae)– Bentgrass, Fescue and Poa

• White Blight (Melanotus phillipsii)– Mainly Fescue but on Bentgrass, Ryegrass and Poa

OVERVIEW OF BASIDIOMYCETES• Fairy Ring (Various Species)

– Type I, II, and III

OVERVIEW OF BASIDIOMYCETES• Localized Dry Spot (Various Species)• Thatch Collapse (Unidentified)

THATCH COLLAPSE SYMPTOMS

• Different From Other Basidiomycetes Diseases– Sunken Circular Patches– Darker Green Turf Within Patches– Mycelium May be Present– On Greens, Tees and Fairways

THATCH DEGRADATION RESULTING IN SUNKEN PATCHES

WHITE MYCELIUM IN THATCH

THATCH COLLAPSE• PATHOGEN: Unknown Basidiomycete

• HOSTS: Creeping Bentgrass, Velvet Bentgrass, others?

• SYMPTOMS: Sunken Green Circular Patches (3” to 1’)

• SIGNS: Mycelium in Thatch and Foliage Following Incubation

SINCE THEN SYMPTOMS HAVE BEEN REPORTED IN…

California

Ohio

Michigan

Montana

Pennsylvania

South Dakota

Australia

New Zealand

HAS OCCURRED ON GOLF COURSES GLOBALLYP

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GENERAL SYMPTOMS DESCRIBED

• Circular Patches 6-18 Inches in Diameter With an Irregular Border– Darker Green Turf from Thatch Degradation– White Mycelia Present on Thatch Layer – Orange Hue within Infested Thatch

• Symptoms Not Limited to One Turf Species– Warm and Cool-Season Turfgrasses

THATCH COLLAPSE SAMPLES WERE INCUBATED

• Consistent Development of Fruiting Bodies Similar to the Artillery Fungus (Sphaerobolus stellatus)

SPHAEROBOLUS STELLATUS

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• White Rot Fungi• Normally Found on Mulch

• Contains Potential Enzymes to Degrade Organic Matter (Valentin et al., 2009)

Valentin, L., B. Kluczek-Turpeinen, P. Oivanen, A. Hatakka, K. Steffen and M Tuomela. 2009. Evaluation of basidiomycetous fungi for pretreatment of contaminated soil. Journal of Chemical Technology and Biotechnology 84:851-858

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OBJECTIVES OF RESEARCH1. Understand Causal Organism

A. Identify Organism by DNA SequencingB. Complete Koch’s PostulatesC. Measure Growth Rates

2. Initiate Management Strategies

CONFIRMATION OF S. STELLATUS• Completed DNA Sequencing • The DNA Sequences Were a 99% Match for

California, Michigan, South Dakota and New Zealand to Known S. stellatus From Mulch.

BUT DOES S. STELLATUS CAUSE THATCH COLLAPSE?

• Completed Koch’s Postulates– Association– Isolation– Inoculation and Symptoms Development– Re-Isolation

KOCH’S POSTULATES• Incubated 12 Mature Penn ‘A-1’ Creeping Bentgrass Plugs at 12°C and 24 hr Light for 6 Weeks• Plugs Inoculated with

– Sterilized Thatch– No Thatch– S. stellatus Infested Thatch

KOCH’S POSTULATES• Data Collection:

– Compressed Thatch Depth Measurement– Percent Total Organic Matter– Means Separated at P < 0.05 According to the Least

Significant Difference Test

FOUND S. STELLATUS CAUSES…• Decreased Thatch Layer from 2.0 cm to 1.45 cm

– Significant Reduction of 28%

0

0.5

1

1.5

2

2.5

A* A

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Compressed Thatch Depth

Un-inoculuated control

Sterilized thatch inoculum

S. stellatus in-fested inoculum

Treatments

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*Combined means followed by the same letter are not significantly different according to LSD test at α = 0.05

FOUND S. STELLATUS CAUSES…• Significant Reduction of Organic Matter 21%

0

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0.6

0.8

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1.2

1.4

1.6

1.8

Organic Matter Content

ControlS. stellatus infested

Treatments

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%)

A*

B

*Combined means followed by the same letter are not significantly different according to LSD test at α = 0.05.

KOCH’S POSTULATES• S. stellatus was Re-isolated from Infested Plugs

Association Isolation

Re-inoculation Re-isolation

GROWTH OF S. STELLATUS• Growth Temperatures

– In Vitro Growth of S. stellatus– Six Temperatures (5, 10, 15, 21, 25 and 30°C)– Radial Mycelia Growth Measured

BIOLOGY OF S. STELLATUS• S. stellatus Optimal Daily Growth Rate at 21-

30°C (70-86°F)

5 10 15 21 25 300

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

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S. stellatus Growth Rate

CAMISD

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SUMMARY • Thatch Collapse Symptoms Observed Globally • S. stellatus Shown to Degrade Organic Matter

– Decreased Thatch Depth 28%– Total Organic Matter Reduced 21%

• Optimal Growth at 70-86°F

FLIED TRIALS FOR MANAGEMENT• Plots Inoculated with S. stellatus Infested

Thatch in May 2012• Developed Symptoms June 2012

FLIED TRIALS FOR MANAGEMENT• Ongoing Trials

– Influence of Nitrogen Sources– Preventive and Curative Fungicidal Control

• Data Collected Through the 2013 Season

Influence of Nitrogen Sources

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16-Aug

21-Aug

26-Aug

31-Aug

5-Sep

10-Sep

15-Sep

20-Sep

25-Sep

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10-Oct

15-Oct

20-Oct

25-Oct

30-Oct4-N

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2

3

4

5

6

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Patch Development Summer 2012

Ammonium NitrateCalcium NitratePotassium NitrateAmmonium SulfateUrea20-20-20

Time

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CURRENT MANAGEMENT SUGGESTIONS• Preventive:

– Manage Thatch Accumulation• Verticut • Aerify• Topdress Regularly

CURRENT MANAGEMENT SUGGESTIONS• After Symptoms Develop

– Topdress for Even Playing Surface• Fungicides?

Common Name Trade Name EC50 (ppm)Polyoxin-D Endorse 2.5 WP 0.201Azoxystrobin Heritage 50WG 0.432Pyraclostrobin Insignia 20WG 0.540Triademifon Bayleton 50DF 0.597Tebuconazole Lynx 45WP (Torque) 0.828Chlorothalonil Daconil Ultrex 82.5 WDG 1.258Flutolanil Prostar 70WP 1.951

Fidanza M. A. and D. D. Davis 2009. In vitro screening of control artillery fungi. J. Environ. Hort. 27:155-158.

CONCLUSIONS• Thatch Collapse is a New Problem in Turf• Sphaerobolus stellatus is a Casual Agent

– Grows Optimally at 70 to 86°F • Possible Management Strategies

– Endorse/Affirm, ProStar, Heritage • Tank Mix with Wetting Agent• Water-in

– Topdress Regularly• Treat Like Fairy Ring

THATCH COLLAPSE RESEARCH• Biology and Epidemiology

• Fungicide Evaluations

• Cultural Management Practices

• Thatch Degrading Enzymes

THATCH DEGRADING ENZYMES• Sidhu et al., 2012 Found Applying Fungal

Laccase Reduced Thatch Layer• S. stellatus Has Similar Enzyme Production• Biodethatching?

Sidhu S. S., Q. Huang, R. N. Carrow and P. L. Raymer. 2012. Use of fungal laccases to facilitate biodethatching: a new approach. Hort Science 47:1536-1542.

Amy M. Baetsen|| Dr. John E. KaminskiThe Pennsylvania State University

Thatch Collapse: A New Disease of Golf Course Turf