Transcript Pests, Diseases and Disorders of Turf

Pests and Diseases of Turf
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Pests
• The few animal pests that cause damage
to turf can be categorised according to the
nature of the damage.
• Pests either eat live plant tissue or
• Pests that mix or disturb the soil or turf
surface.
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Tissue Eating Pests
• In the main these are species of insects of
which the two most common and
damaging are the
– Leather jacket and the
– Chafer grub
• Letherjackets are the larval form of the
Daddy-Long-Legs. or Crane fly.
• Chafer grub are the larva of the Chafer
Beetle
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Leatherjacket
(Tipula Paludosa)
• Leatherjackets are 20-40mm long brown or
greyish grubs that occur in the surface of the
turf.
• The damage they cause by eating plant roots is
usually first observed by patches of pale-strawbrown grass.
• The grass subsequently dies leaving bare
parches.
• Symptoms are most obvious and severe in dry
sunny weather
• Leatherjackets are common on large open areas
of undisturbed grassland.
• Leatherjackets prefer heaver soils
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Leatherjacket Larva and the Adult
(Tipula Paludosa)
• After heavy rain or having thoroughly
watered any yellow patches in the lawn,
cover them with black plastic sacks and
leave overnight. The leatherjackets will
come to the surface and can be
collected in the morning
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Leatherjacket Control
Treat the lawn with an insecticide
containing imidacloprid from May
to October.
Use the biological control Steinernema feltiae, which should be
applied while the ground is still moist and warm in late-autumn.
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Chafer grubs
(Phyllopertha Horticola)
• Chafer grubs have fat pale waxy bodies
with a characteristic brown head.
• They may be up to 1 ½ inches in length
and are always “comma” shaped.
• Damage is similar to that of the leather
jacket, although they prefer lighter soils.
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Chafer Grub Larva and the Adult
Click Beetle (Phyllopertha
Horticola)
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Chafer Grub Larva Control
• You can buy pathogenic nematodes, Heterorhabditis
megidis, which attack the larvae by infecting them with a
fatal bacterial disease. These can be watered into the soil
during the summer to early autumn when the ground is
moist and soil temperature range between 12-20ºC (5568ºC).
• A pesticide - Provado Lawn Grub Killer - is available to
home gardeners for controlling chafer grubs in lawns.
The product contains imidacloprid.
• The best time for treatment is in June to July, when the
more vulnerable young larvae are present.
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Cutworms (Noctua pronuba)
• Other pests in this category are cutworms
however these rarely need control.
• Cutworms are the larvae (caterpillars) of
several species of night-flying moths.
• There are no approved insecticides
currently available to amateur gardeners
to control cutworms.
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Wireworms (Agriotes species )
• Other pests in this category are wireworms
however these rarely need control.
• Wireworms are the larvae of the click
beetle.
• There are no effective chemicals available
for wireworm control
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Cutworms (Noctua pronuba)
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Wireworm (Agriotes species)
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Soil and Turf Disturbing Pests
• As a pest the most serious one is the
earthworm.
• Occasionally birds such as rooks and
starlings may cause damage to the
surface in their search for grubs and
worms.
• Other pests in this category are mammals
such as moles, rabbits, dogs, foxes and
deer.
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Problems of Worms in Turf
• Casts may smoother turf
grasses
• Casts are unsightly
• Casts smear on the
playing surface
• Casts may contain small
stones which may
damage mowers
• Casts provide an ideal
seed seedbed for
germinating weeds
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• Casts produce an uneven
playing surface
• May produce a squelchy,
slow drying sword
• The presence of worms
may encourage mole
activity
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Control of Earthworms
• Earthworm activity can be reduced by
appropriate cultural methods by
• Reducing soil pH and
• Organic matter content
• Worms do not like acidic conditions and
feed off organic matter.
• Use acidic fertilisers and implement
regular scarification and aeration to
remove thatch and organic matter
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Diseases of Turf Grass
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Diseases of Turf Grass
• In horticulture generally, fungal, bacterial and
viral agents may cause plant disease, however,
in turf fungi cause the vast majority of disease.
• Not all fungi however associated with turf and
soil are harmful. Many are beneficial as they
decompose plant material e.g. thatch and
organic matter in turn releasing nutrients.
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Factors Affecting the Growth of
Fungi
• Temperature – fungi do not grow well
below about five degrees centigrade but
flourish around 20 degrees centigrade
• Moisture – is necessary for germination of
fungal spores. High humidity also
encourages the spread of fungi.
• Light – plants in shade are more prone to
disease because of weak growth.
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Factors Affecting the Growth of
Fungi
• Wind – air movement removes water from
the grass keeping turf dry and less
susceptible to disease.
• Soil pH – can affect fungal growth and
development
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Cultural Control of Turf Grass
Disease
• Maintain a vigorous
growing sward
• Moisture control to avoid
humid surface conditions,
e.g. switching or brushing
• Ensure free movement of
air over turf surface
• Regular aeration
treatments
• Reduce thatch by
scarification/verticutting
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• Box off clippings
• Avoid excessive nitrogen
fertilisers especially in
autumn
• Avoid the use of lime
• Use resistant grass
cultivars
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Chemical Control of Fungal
Disease in Turf
Systemic Fungicides
• Used during periods
of active growth and
are absorbed by the
foliage and
transolicated
throughout the plant
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Contact Fungicides
• These chemicals act
upon the disease on
contact with it
• These are frequently
used during the
dormant growth
periods but can be
used at any time of
the year.
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Fusarium Patch - Snow mould
(Fusarium nivale)
• This is the
commonest fungal
disease of lawns.
• Prevalent in autumn
and in spring.
• In moist weather the
edges of the diseased
areas may be
covered with white or
pale pink fluffy mould.
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• The first signs are of
small areas yellow
grass.
• Patches increase in
size.
• The grass in the
patches is killed.
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Fusarium Patch - Snow mould
(Fusarium nivale)
Avoiding and curing the problem
• Good lawn care is the secret.
• Feed your lawn in spring and autumn.
• Spike the turf and avoid mowing too
closely
• Prevention is better that cure as there are
no fungicides available to the amateur
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Fusarium Patch - Snow mould
(Fusarium nivale)
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Red Thread (Laetisaria fuciformis)
• Fine-leaved grasses
are susceptible to
attack.
• In late summer or
autumn look for
irregular patches of
bleached grass which
later take on a pinkish
tinge.
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• In moist weather you
will find small red
needle like growths
standing up from the
leaves of grass.
• Grass is not killed but
it is unsightly until the
bleached patches
recover
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Red Thread (Laetisaria fuciformis)
Avoiding and curing the problem
• Curing the disease is never easy, avoid
infection.
• Do not use a high nitrogen-rich fertiliser in
autumn or winter, spike the turf regularly
and never walk on the lawn when it is
covered with snow.
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Red Thread (Laetisaria fuciformis)
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Fairy rings (Marasmius oreades)
• Rings develop on the turf which increases
in size as the fungus spreads.
• Around the periphery of the ring one or
more zones of very lush green grass
develop.
• Between the rings the area is dead and
brown.
• Pale brown slender toadstools 4-10cm
high may develop
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Fairy rings (Maramius oreades)
Avoiding and curing the problem
• There is no chemical control available.
• Rake up and dispose of toadstools, before the
caps open and release spores.
• Mow affected area separately collect and burn
mowings.
• Dig out the ring to a depth of 30cm and
extending 30cm beyond the edges of the ring.
• Fill in with new topsoil and re-seed.
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Fairy rings (Maramius oreades)
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Sources of Information
• Rolawn
http://www.rolawndirect.co.uk/./
• Bayer Garden
http://www.bayergarden.co.uk/
• The Maintenance Procedures of Turf
http://www.onlineturf.co.uk/static/Chapter3.pdf
• Hessayon, D. G. (1997) The Lawn Expert. pbi Publications, Waltham
cross.
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