Identification of Diseases in Sports turf

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Identification of Diseases in Sports turf

• Andrew Wight

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Understanding fungal diseases

• Fungi, diverse groups of either single-celled or
  multicellular organisms that obtain food by
  direct absorption of nutrients. Some of these
  fungi are parasitic (feed on living matter) and
  cause serious plant diseases.
• Most fungi reproduce by spores, which are tiny
  particles of protoplasm. The common mushroom may
  form 12 billion or more spores on its fruiting
  body the giant puffball may produce several
  trillion.
• These spores can be spread by the wind,
  machinery, peoples feet etc. The spores and the
  fungi themselves can remain inactive in the soil
  for long periods until conditions are suitable
  for fungal growth. It is for this reason that
  fungal attacks can suddenly appear in turf grass
  swards

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Sports turf diseases

• Diseases come in 3 types
• Fungi
• Bacteria
• Viral
• But in the UK nearly all grass diseases are
  caused by fungi

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Disease Triangle
Host (Grass Plant)
Environment
Pathogen
(Disease that attacks grass)
(Where grass lives)
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Common UK sports turf diseases

• 1) Fusarium patch
• 2) Red thread
• 3) Anthracnose
• 4) Take-all patch
• 5) Leaf spot
• 6) Rust
• 7) Fairy rings
• 8) Grey snow mould

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Fusarium Patch

• Occurs in cool, wet humid conditions
• Orange/brown spots start at 3cm
• Grows to 10cm with outer edge dark brown when
  active
• Causing factors
• Too much Nitrogen fertiliser
• Shade
• Heavy dew
• Poor drainage
• High thatch content
• Poa annua is very susceptible

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Cultural control of fusarium

• The best defence against Fusarium Patch Disease
  is to have healthy turf. This means considering
  the growing environment that the turf is living
  within throughout the seasons.
• Provision of light, air, food and water are
  essential for a healthy sward. Fusarium, like
  most fungi, relishes damp, enclosed, still, and
  low light conditions. If it is possible to
  improve any of these factors this will aid
  disease resistance in the future.
• An appropriate maintenance regime should be
  followed, including correct mowing,
  scarification, feeding, weeding and aeration.

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Red Thread

• Occurs in mild, damp conditions
• Causes
• Low nitrogen levels
• Symptoms
• Long thin red needles in patches of bleached
  straw like turf
• Crown rarely infected so doesnt kill grass
• Control
• Applications of nitrogen fertiliser if
  appropriate for time of the year will help
  control the symptoms

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Anthracnose basal rot

• Symptoms discolored turf rotting of base of
  plant
• Yellowing of youngest leaf
• Occurs in
• Cool wet conditions
• Likes compacted wet root zones that have low
  fertility
• Control
• Improve surface drainage
• Reduce any shade
• Reduce annual meadow grass content of sward

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Take all Patch

• Occurs in summer/autumn months in warm, dry
  weather
• Symptoms
• Patches/rings up to 30cm
• Bent grass mainly affected (often weeds and
  unaffected fescue can be seen in the affected
  areas).
• Small black needles (fruiting bodies of fungus)
  1mm long can sometimes be seen on the leaf
• Control
• Over-seed areas with fescue grasses that are not
  affected by the disease.

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Dollar Spot
The disease shows as 2 to 4 cm diameter bleached
spots which do not increase much in size but
which do coalesce to form large areas of bleached
turf. Dollar spot can develop either during
late spring/early summer or late autumn but more
severe outbreaks appear to develop in the autumn.
Drought-stressed turf is particularly
susceptible to infection but high humidity or
heavy dew are necessary for disease development.
High daytime temperatures and low night time
temperatures, when combined with the presence of
heavy dew, are ideal conditions for this disease.
Turf grass grown under low nitrogen nutrition is
more susceptible to dollar spot but root zone pH
does not appear to influence susceptibility. Remo
val of dew is essential to minimise the chance of
infection. Adequate nitrogen nutrition is
critical both to minimise the onset of the
disease and also to aid recovery of an affected
sward.
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Snow Mould

• Snow mould damage looks like circular patches
  (3"-12") of dead and matted grass. Depending on
  the severity of the outbreak, the circles can
  coalesce and become a large mass.
• Snow mould is a fungal disease that appears in
  the early spring as the snow melts. There are two
  types of snow mould. Grey snow mould (also known
  as Typhula blight) and pink snow mould (sometimes
  referred to as Fusarium patch). Pink snow mould
  infects the crown of the plant and can cause more
  severe injury than grey snow mould which only
  infects the leaf tissue.
• Prevention
• Avoid excessive nitrogen fertilizers in the
• autumn
• Reduce thatch levels

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Type 1 Fairy Ring

• Symptoms
• Ring of dead grass sometimes with mushrooms
• present.
• Cause-
• the fungi in the fairy ring produce a waxy
  substance that coats the soil
• particles in the affected area reducing the
  amount of water that can enter
• the soil. This weakens the grass and the fungi
  attack and break down the
• weakened grass. The bright green grass on either
  side of the dead ring is caused
• by nutrients been released as the fungi break
  down organic matter.
• Control
• Wetting agents can help reduce the impact but to
  control the issue an approved
• fungicide must be used. Attempts can be made to
  remove affected soil by
• digging out the ring but this is rarely
  successful.

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Leaf spot

• Occurs in mild, wet conditions
• Affects mainly Poa grasses but can affect Bents,
  Rye and Fescue
• Leaf tissue has red spots
• Attacks stressed areas of turf first
• Causes
• Nutrient deficiencies
• Cool / warm temperatures
• Moist / wet surfaces
• Over feeding with Nitrogen (creating lush growth)
  
• Over watering
• Close mowing
• Shade
• Poor air movement
• Susceptible grass species
• High soil pH

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Rust

• Symptoms
• Orange lesions on leaf
• Cause one of the main cause is under nourished
  turf.
• Doesnt necessarily kill grass, but is unsightly
  and can stain players clothing
• Rust Disease tends to be present on Rye Grasses
  and Smooth Stalked Meadow Grass. It can be a
  problem on football pitches due to Rye grass
  content.
• Control is not normally required unless outbreak
  is severe in which case an approved fungicide
  should be applied. In addition correct fertiliser
  applications will help avoid the disease

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Conditions that encourage diseases

• 1) Extremes of temperature
• 2) Unsuitable pH
• 3) Shade
• 4) Nutrient imbalance
• 5) Moisture (wetness of surface)

• 6) Soil condition (compaction)
• 7) Grass susceptibility
• 8) Humid conditions (dew)
• 9) Depth of thatch

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Methods of controlling diseases

• 1) Suitable pH in soil
• 2) Improve light (reduce shade)
• 3) Improve air circulation
• 4) Aeration improve root growth and drainage
• 5) Control thatch levels
• 6) Remove surface moisture
• 7) Discourage Annual Meadow grass
• 8) Correct level of fertiliser application
• 9) Reduce grass stress (correct mowing,
  scarifying etc.)
• 10) Use a suitable fungicide control