Turf Disease

Welcome to the Turf Disease course.

Please study all the Turf Disease information below, understanding the symptoms, host and management.

Lesson Notes

Turf disease - Carefully study the Turf disease introduction section to learn about what turf diseases are, when they occur and why what to do when they do appear.

Grass species - learn which type of grass species are more susceptible to certain turf diseases.

Other factors - understand how other factors increase the likelihood of turf disease.

Control - learn different types of maintenance procedures that help control and reduce the incidence of disease.

Fungicide treatments - for each listed disease, study the various active ingredients available that help prevent and cure turf disease

Introduction to Turf Disease

What

There are a number of turf diseases that can occur on turf in the UK, some more common than others. The vast majority are caused by pathogenic fungi that are present in the soil or on surrounding vegetation.

An important role of the greenkeeper / groundsman is to manage turf health on a regular basis creating an environment less susceptible to disease. It's important to recognise the symptoms, understand the factors that encourage the pathogen to spread and know how to control them with both cultural measures and, as a last resort, the use of an appropriate fungicide.

When

Turf diseases can occur at most times of the year. Best practise is to apply the right products at the right time such as fertilisers, bio-stimulants and pgr's in line with weather conditions optimising turf health that may prevent disease occuring. The most critical time for this is during the late autumn and early spring when grass growth is slow or non-existent due to low-temperature and light levels. At these times of the year any damage done to the grass will persist for many weeks until conditions for stronger growth return to the spring.

Why

Turf disease can sometimes kill grasses and seriously affects the playability and appearance of the turf. Surfaces can become slippery due to the slimy nature of the fungal pathogen that is present on the leaf and also as a result of exposing moist soil and mud where the grass is killed or thinned by the effects of the disease.

Forcing grass to grow at certain times of the year can produce soft growth that is more vulnerable to attack by the fungus. Injury to the grass leaf caused by mowing, aeration procedures, foot traffic, machinery and abrasive top dressings can provide an easy access point for the invading fungal pathogen. We must also manage moisture levels, soil pH and thatch levels to further prevent disease occurrence while ensuring all nutrutional requirements are met by conducting a soil analysis.

Weather can also assist in the development of turf disease causing abiotic stresses on the plant. Abiotic stresses, such as low or high temperature, deficient or excessive water, high salinity, heavy metals, and ultraviolet radiation, are hostile to plant growth and development.

Injury to grass plants can also be caused by parasitic insects feeding on the roots and stems which can open the way to invading fungi.

How

Managing turf surfaces calls for knowledge of each of the main diseases that can affect the playing surface. In the following section we will cover each disease from the identification through to the cure - detailing the symptoms, factors affecting spread, time of year and both cultural and chemical control measures.

Turf Disease ID

Study each turf disease below, this will be on the test.

Fusarium Patch

Microdochium nivale

  • Most damaging disease that occurs on sports turf

Caused by the fungal pathogen Microdochium nivale

Symptoms

  • Small orange/ brown spots that can go on to produce much larger irregular scars

  • Spores may give a slimy feel to the disease

  • Dark brown on outer margin when disease is active

  • Pink or white mycelium may be seen around the edge

  • Pale or straw-coloured and dry when inactive

HOST-All major turf species attacked

Conditions which favour the disease

  • Combination of humid conditions and moist turf surfaces

  • Poor drainage

  • Excessive thatch

  • High soil pH

  • Excessive top dressing

  • Excessive nitrogen input

Management

  • Moisture control

  • Address drainage issues

  • Regular aeration

  • Thatch reduction

Anthracnose

Colletotrichum spp.

Caused by the fungus Colletotrichum graminicola. The pathogen can result in two types of disease: foliar blight and basal rot.

Symptoms

  • Usually seen in late summer but can also be found all year round

  • Yellow individual plants are seen or single leaf infected

  • Distinct rotting at the base

  • Small black pin head structures appear these are the spore structures

  • Infected plants come away easily

Host

Anthracnose can effect all turf species but is predominately prevalent in Poa annua dominant swards in the UK. but can occur on ryegrass and fescue

Conditions which favour the disease

  • Compaction e.g. around the pin positions

  • Low soil fertility

  • Prolonged soil wetness

  • Most prevalent during the summer and early autumn months

Management

  • Reduce compaction

  • Regular aeration

  • Timely and moderate nitrogen applications – Agrovista Amenity Fertiliser tank mixes

  • Overseed with fescue and bent grass cultivars

  • Fungicide

Red Thread

Laetisaria fuciformis

  • Symptoms

  • Usually seen during the summer and autumn months but can be all year round

  • Damage grass with pink or red appearance

  • Red needles are the survival phase of the fungus

  • Leaves die back from the tip and damage is usually superficial

Host

All cool season grasses – particularly ryegrass and red fescue

Conditions which favour the disease

  • Mild temperature (20C)

  • Damp turf surface

  • Wide pH values 3.5-7.5

  • Often associated with turf of low fertility, particularly nitrogen

Management

  • Select lower resistance cultivars (BSPB Turfgrass seed guide)

  • Apply a nitrogen fertiliser

  • Fungicide

Take-all patch

Gaeumannomyces graminis

  • Caused by Gaeumannomyces graminis

Symptoms

  • Usually appears during summer months through in to the late autumn

  • Saucer shaped

  • Slightly depressed areas of infected grass appearing bronze in colour

  • Saucers can be up to 0.3m in diameter

  • The bent dies and resistant plants remain e.g. Poa, fescue and weeds

  • Blackened roots and rhizomes of infected bent grass due to fungus

Host

Only bent grass

Conditions which favour the disease

  • Excessive thatch

  • Poor drainage

  • High soil pH levels

Management

  • Take-all decline

  • pH adjustment

  • Build up of microbes in sand greens

  • Avoid high pH top dressing material

  • Sulphate of iron

  • Water pH

  • Sulphate of iron

  • Overseed with fescue

  • Fungicide

Dollar spot

Sclerotinia homoeocarpa

  • Symptoms

  • Usually tiny spots approximately 10-20 mm in diameter

  • Usually distinct and circular but can form larger infected areas

  • Usually dry, bleached white appearance or straw-coloured

Host

Fescue / bent

Conditions which favour the disease

  • Susceptible grasses

  • Low fertility

  • Warm humid environmental conditions 16-27

Management

  • Maintain adequate fertility, especially nitrogen

  • Adequate water

  • Overseed with more disease tolerant varieties

  • Sloww release feed

  • Remove dew

  • Trees / shrub trimming around greens to imporve air circulation and increase turf drying

  • Fungicide application

Leaf Spot / Melting Out

Drechslera poae

  • Very common and only occasionally causes serious damage

Symptoms

  • Overall decline in the quality of the sward resulting in streaks or patches of affected grass

  • Mottled yellow from the tip downwards

  • A red / brown border separating the affected and healthy tissue

  • Melting out- severe foliage dieback or melting out

Host

Most if not all turf grass

Conditions which favour the disease

  • warm humid conditions

  • Rainfall and irrigation are important in the spread of these diseases as spores disseminated by water splash

  • Stressed or senescing leaf tissue is often prone to disease

Management

  • Avoid over application of fertiliser but encourage moderate growth

  • Raise height of cut

  • Keep thatch depth to a minimum

  • Keep the surface dry – good air movement

Brown Patch

Rhizoctonia solani

  • Symptoms

  • Soil borne fungus

  • Water soaked patches

  • Greyish purple smoke ring to patches

  • Brown or straw-coloured

  • Generally restricted to leaf tissue but can kill under favourable conditions

Host

  • All species but mainly bents

Conditions which favour the disease

  • Warm humid weather giving prolonged periods of leaf wetness

  • High nitrogen input

Management

  • Good water management - avoid overwatering

  • Water early in the day, so grass dries well by night

  • Switching to remove dew

  • Avoid excessive nitrogen fertiliser applications

  • Work to reduce thatch

  • Contact fungicide to prevent spread through the turf

Etiolated growth

Ghost Grass

Symptoms are etiolation / white leaves possible dilution of chlorophyll

The disease may be creating or causing the release of gibberellic compounds. Seen usually after several days of cloudy and overcast conditions. Also, in shady areas

Yellow Tuft

Sclerophthora macrospora

Sclerophthora macrospora

  • Small yellow patches up to 30 mm in diameter

  • Shoots easily detached from the turf

  • All grasses particularly bent

  • Usually seen in late spring and autumn during cool and wet weather

  • Avoid excessive fertiliser application

Fairy Rings

Symptoms

  • Start from a central point and grow outwards

  • A number of causal fungi

  • Rate of growth will depend on soil structure and the presence of organic matter

  • For convenience grouped as either type 1,2 or 3 but also superficial or thatch fungi


Superficial fairy rings

  • caused by a non sporing basidiomycetes

  • damage mostly discolouration

  • mostly during summer and autumn

  • can identify fungal mycelia within the thatch layer

  • musty smell

  • Fungi will break down the thatch and will cause a depression

  • Can appear yellow or bleached

  • May not see entire ring

  • Mainly on fine turf

  • Use iron to disguise rings

  • Top dress

Type 1 Fairy Ring

Type 1

  • Usually seen in fairway or out-field areas but generally not fine turf

  • Seen as dead or severely stressed turf

  • Characteristic musty smell in soil

  • Rings that touch each other will disappear where they touch as they mutually inhibit each other

Type 2 Fairy Ring

  • Common on areas of fine turf – seen as areas of stimulated grass growth. Faster growing than unaffected turf

  • Apply a nitrogen or iron based feed to mask discoloration on turf.

Type 3 Fairy Ring

  • Very common with no major detrimental effects to turf health.

  • Only seen when fruiting bodies are present and generally in the autumn.

  • No control necessary

All course information and chemical recommendations are taken from product labels and are not based on agrovista amenity advice. This information is correct and true as of 28/4/21.