Turfgrass Diseases (Intermediate)

© Myerscough College 2011

J Kno

wles@

myers

coug

h.ac.u

k

Turf G

rass D

isease

Man

agem

ent

The management and control of turf grass diseases starts with the principle understanding of the disease triangle. By understanding and managing the turf environment through physical and cultural applications the use of chemical pesticides can be reduced. This session book promotes working towards sustainable and integrated pest management. The cause and effect of diseases as well as fungicids are detailed here. This session is relevant for the QCF Units 210 (L5.1), 350 (CU80), & NVQ CU110

THIS IS A DRAFT DOCUMENT. THE FORMAT AND

GENERAL IDEA IS UP FOR REVIEW.

Myerscough College St Michaels Road, Bilsbarrow, Preston,

England 01995 642222

[email protected]

©Myerscough College 2011

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Turf Grass Disease Management The Disease Triangle

Disease symptoms occur on grasses as an effect of three associated causes.

These causes are: environmental conditions, type of pathogen and the type of host.

This can be best illustrated as the Disease Triangle.

STRETCH YOUR KNOWLEDGESTRETCH YOUR KNOWLEDGESTRETCH YOUR KNOWLEDGESTRETCH YOUR KNOWLEDGE

� Pathogen is the fungus that attacks the grass plant.

� Environment is the weather, the climate, the micro-climate, turf

environment, and soil environment.

� Host is the particular species of grass.

Symptoms

Host


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A combination of a pathogen, with a favourable environment and an available

host can results in the disease. For example in this cause and effect diagrams;

The disease can change by even a subtle change to one of the causes, as

shown immediately above. Pink Snow Mould, has the same pathogen, same host,

with slightly differnet enviromental conditions to Microdochuim Patch. As the name

suggests, Pink Snow Mould usually occurs under and after a snow covering.

Environment

Temperatures between 0oC to 20oC

Damp

Drizzle

Rasied soil pH

Poor surface drainage

Thatch

Pathogen

Microdochium nivale

Note: for the purposes of diseases analysis the pathogen should always be considered to be available

Host

Annual Meadow Grass

Bent grass

Disease:

Microdochium Patch

Environment

Temperatures between -20oC to 20oC

cold

Rasied soil pH

Poor surface drainage

Thatch

Pathogen

Microdochium nivale

Note: for the purposes of diseases analysis the pathogen should always be considered to be available

Host

Annual Meadow Grass

Bent grass

Disease:

Pink Snow Mould


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Integrated Pest Management It is important to control diseases, especially the diseases that are

detrimental to the playing surface. Grasses are subject to many diseases and

disorders, some are not a problem to sports turf, while others can result in bare

areas and loss of surface.

Reporting and inspecting for diseases is an important part of groundsmanship

and greenkeeping. Inspecting the turf is about being vigilant. There are good

opportunities for inspecting the turf health, for example; while out cutting, changing

holes, divoting, and switching.

By immediately reporting any signs of disease to a senior member of the team

it can save time, resources and money. Importantly, the quality and integrity of the

playing surface can be upheld. This close monitoring forms the essence of an

integrated management control for diseases. The procedure for controlling diseases

is illustrated below. This procedure also forms part of an Integrated Pest

Management (IPM) monitoring role.

Importantly, this procedure is not exclusive to pesticide application and treatment

must be interpreted as cultural, physical and chemical.

Identification &

record

report to an

appropriate person

identification

confirmed by

appropriate person

treatment planning.

Including risk,

LERAP and COSHH

assessments

record details of

treatment

review the

effectiveness of the

treatment


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Treatments Controlling and managing the onset of any threat to turf health is the

continuing role of the Greenkeeper and Groundsman. The head Greenkeeper or

groundsman will spend much of their time planning and preparing the surface for

play and continued (sustainable) health.

Physical Many tasks and routine operations are considered as pro-active physical and

cultural management against the onset of a turf health threat. Here are examples of

physical controls, clearly these are not distinct from cultural methods:

• aeration • switching

• top-dressing • scarifying

• drainage installation • cutting blades are sharp

Cultural By changing the culture of the turf it is described as a cultural treatment. For

example; introducing grass species that are resistant or less susceptible to the

diseases that are most detrimental to sports turf, see the susceptible Species

section. Increasing the beneficial soil bacteria (organic fertiliser) populations to

antagonise pathogenic fungi has been proven as a method to reduce disease

incidence.

Plant Protection Products (Chemical) The use of plant protection products include the use of pesticides, otherwise

known as a chemical control. There are additional chemicals that are not pesticides

that are used to control fungi. An example of this is the application of surfactants

(wetting agents).

All use of pesticides as defined by Chemicals Regulation Directorate, will need

applying and recording in line with the relevant legislation and codes of practice e.g.

the Control of Pesticides Regulations Act.

These methods of treatment are linked with the associated causes as

described on page one. By intervening on the associated causes it can disrupt the

association and prevent disease onset.


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Susceptible Species The following table gives an overview of diseases along with the species that

are susceptible.

STRETCH YOUR KNOWLSTRETCH YOUR KNOWLSTRETCH YOUR KNOWLSTRETCH YOUR KNOWLEDGEEDGEEDGEEDGE

Diseases of turfgrass are can either be bacterial, viral or fungal. Here we are mainly

concerned with fungal infections as these are most common in sports turf. The

facultative parasitic fungi of turf obtain their nutrition from the host plant, in many

cases of the diseases will die when the host plant dies. Saprophytic fungi (Fairy ring

and Thatch Fungus) feed on decaying organic matter, such as underlying decaying

tree roots and thatch.

Disease

Susceptible Turfgrasses*

Poa

pratensis

Poa annua

Agrostis

stolonifera

Agrostis

capillaris

Festuca

rubra ssp.

Lolium

arundinaceu

m

Lolium

perenne

Anthracnose x xx x xx xx

Brown Patch x xx xx xx x xx xx

Fairy ring x x x x x x x

Leaf spot xx xx xx x xx x x

Microdochium Patch x xx xx xx x x x

Phythium Blight x xx xx xx x x xx

Pink Snow Mould x xx xx xx x x x

Red Thread xx x x xx xx

Stem Rust xx x x x

Take-All Patch xx xx

Thatch Fungus (disorder) x x x x x x x

Yellow Tuft x x x x x x x

*

X Susceptable under certain conditions or of minor importance

XX Disease is of primary importance

Adapted from: Turgeon, A. 1996. Turfgrass management (4th Ed.) p.258-259


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Fungicides The following table is an overview of the common fungicides that are

protective and curative against turfgrass diseases. The fungicide product label will

give detailed information on application rates and which diseases it can control.

If unsure, as to the identity or which chemical to use it is advisable to seek

the advice of a BASIS registered Turfgrass Agronomist.

Active Ingredient Mode of Action

Chlorothalonil

contact

Iprodione

local penetrant

Inhibits spore germination and growth

Pyraclostrobin

local penetrant

Prevents electron transfer in mitochondria – leads to insufficient energy and so prevents growth

Trifloxystrobin

local penetrant

Carbendazim

Acropetal penetrant

Affects fungal cell division – prevents growth and germination

Thiophanate-methyl

Acropetal penetrant

Fenarimol

Acropetal penetrant

Disrupts ergosterol production – prevents growth

Mycobutanil

Acropetal penetrant

Azoxystrobin

Acropetal penetrant

Prevents electron transfer


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Summary The principle of the diseases triangle is the underpinning knowledge for

sustainable turf management and applying the fundamentals is the basis for

Integrated Pest Management.

By understanding and managing the turf environment through physical and

cultural applications, the use of chemical pesticides can be reduced.

Fundamental skills in turf disease identification are necessary skills for the

modern Greenkeeper and Groundsman. Along with good skills in identifying turf

diseases accurately, it is also necessary to know the integrated management controls

to reduce disease incidence.

Links The UK Turfgrass Disease Centre

http://www.ukturfgrassdiseasecentre.co.uk

Penn State Univesity (Managing Turfgrass Diseases)

http://cropsoil.psu.edu/turf/extension/factsheets/managing-diseases

Bibilography Turgeon. A. 1996. Turfgrass management (4th Ed.). Prentice hall

York, C. 1998. Turfgrass Diseases & Associated Disorders. STRI

Mann, R. 2009. Approved Turfgrass Fungicides. STRI (accessed online 28/10/11)


8

Author Jonathan Knowles is a Training Co-ordinator working in the Skills & Enterprise

Directorate at Myerscough College. Contact Jonathan on email;

[email protected] , or by phone 01995 642222.

Documents

Turfgrass Diseases (Intermediate)