Reproduced by courtesy of the Golf Club Secretary
- Friend or Foe ? __________________________________________________________________
A course management
column by A J Beggs BSc Hons, STRI Manager/R & A Agronomist
our days begin to shorten and the leaves adopt their golden hues, our thoughts
turn from producing the perfect putting surfaces to protecting them from winter
attack is still our biggest concern and the fungus that causes Anthracnose (Colletotrichum
graminicola) is becoming more common on golf greens across the country. At some
Clubs it is now more common than Fusarium and is the major weakening effect on
greens through the autumn and winter. It is the most regularly mis-diagnosed disease
and this can be very damaging for those of you with an abundance of annual meadow
grass (Poa annua) - the host species of the fungus.
Anthracnose can attack the turf at any time of the year but stressed annual meadow
grass plants are particularly vulnerable during the autumn and winter months.
Diseased plants show general yellowing and thinning as the fungus attacks and
rots the crown. Individual plants can be easily removed from the turf and blackened
bases can often be seen by the naked eye. The amount of damage depends on many
factors (see below) but it is important to realise that the disease can be devastating
if the condition and the factors that cause it are ignored.
with all disease management, prevention is better than cure. However, unlike some
other fungal diseases that respond well to chemical attack, Anthracnose often
recurs after treatment. Its spread can be halted by fungicides but if the underlying
causes of the disease are not corrected it will return more aggressively than
following factors are known to contribute and encourage the disease :
Poor surface drainage - there are many possible causes of this including poor
green construction, contour collection, trapped layers of organic matter or thatch
in the upper profile, compaction, etc. Poor drainage induced by compaction is
becoming more common as a result of increased use of sometimes small greens where
pin space is restricted.
Annual meadow grass - the presence of annual meadow grass in itself is not
a cause of the disease. However, the more of this grass a green has, the more
likely Anthracnose will be seen.
Low fertility - Anthracnose is a disease that attacks turf in a state of low
fertility. In this respect it is the opposite of Fusarium, which tends to attack
the over-fed turf.
Over-irrigation - gross over-irrigation or an old system that fails to deliver
in an accurate manner can encourage Anthracnose.
Low mowing - prolonged low mowing, particularly in late summer and autumn,
can pre-dispose the turf to disease especially if annual meadow grass is abundant.
It is a stress factor that can be avoided without compromising pace.
Dry Patch - the link between dry patch and Anthracnose is an interesting one.
it is common to find autumn disease on turf previously affected by Dry Patch.
Clearly Dry patch is not a cause but it may be a pre-cursor having weakened/stressed
the turf through drought.
your Club is familiar with the above issues, it may well be that you have or are
likely to have a problem with Anthracnose. The following cultural initiatives
may help :
It is important that the Club makes the most of its inherent construction type,
maximises the surface flow of water off putting greens and prevents surface flow
onto them. It is also vital that it mitigates the damaging effects of play. This
means effective and timely aeration, regular top dressing and the installation
of extra drainage in some circumstances. Furthermore, do not be frightened of
resting surfaces where necessary.
Turf dominated by annual meadow grass will always be vulnerable to attack by the
Anthracnose fungus. Those that manage for it are asking for trouble. Eradication
may be impossible but good traditional greenkeeping should enable its presence
to be minimised and thereby its vulnerability to Anthracnose.
Aim to apply nitrogen in a balanced fashion through the growing season. Do not
go for too long between applications and with warmer autumns and increased play
there may be a case for Applying that final feed a little later than was the case
twenty years ago. This is particularly true if managing perched water table greens
with a sand dominated root zone.
The importance of effectively removing excess moisture in the form of rainfall
has already been emphasised. It is also vital that the Club does not over apply
its own. If the Club has an automatic watering system ensure that it is operating
effectively and supplement it as necessary with hand irrigation to achieve good
coverage. The gross over-application of irrigation water to some areas of turf
and not enough to others is a sure way of promoting the disease.
Avoid low mowing for long periods. A good greenkeeper knows the heights of cut
his swards will tolerate. Use local knowledge together with modern techniques,
such as improved verticutting and brushing, to maximise pace without over stressing
Use high quality wetting agents in a pro-active manner to prevent Dry Patch during
the summer months. If the greens are particularly prone to this condition, there
may be merit in working a root zone injection treatment into the summer maintenance
is far more than a troublesome disease - it is a biological indicator of trouble
ahead. We live in an age where golf is as popular as it has ever been and some
of our older golf courses on heavier soils are struggling to cope. Increasing
susceptibility to Anthracnose can be a sign that redevelopment or reconstriuction
could be necessary. However, it may also be a sign that the current maintenance
initiatives are inappropriate or insufficiently intensive. Whichever it is, do
not disregard a disease that can be both a friend and a foe. Use the signs it
is giving to the Club's advantage.
Reproduced by courtesy of the
Golf Club Secretary November 2001