Dollar Spot lawn disease
With the right lawn care program dollar spot should not be a problem
and it is more often or not the result of a neglected lawn. Dollar
spot is a serious lawn disease as it can effect and kill the whole
of the grass plant including the roots. This means that affected
areas of the lawn will often need reseeding. Dollar spot will infect
a large number of different grass varieties.
Dollar spot symptoms
As its name suggests Dollar Spot is a lawn disease that results
in silver / grey spots appearing on your lawn. These spots can vary
from 1 to 6 inches in diameter and the spots can also overlap to
form larger patches of diseased lawn.
The fungus that causes dollar spot will result in the grass blades
having tell tale tan coloured legions with red / brown edges that
have an hour glass shape.
Dollar spot causes
Dollar spot is caused by a fungus. The fungus survives over winter
by taking hold on plant matter that appears in the layer of thatch
that occurs in the lawn, it also inhabits plant matter in the soil.
In winter time the fungus is not actively growing but when the warmer
temperatures (70-90° F) are reached in spring the fungus
will start growing and spreading.
So what are the environmental conditions that are ideal for growth
of the fungus and therefore the source of the cause of dollar spot?
- Lack of soil moisture - dollar spot will thrive in lawns which
aren't watered properly. A low soil moisture content will help
dollar spot continue its advance.
- Lack of Nitrogen - lawns require Nitrogen for leaf growth and
a lawn that has adequate nitrogen levels in it will be more vigorous
and resistant to disease.
- High levels of thatch - prevent water penetrating into the soil
and provide good conditions for the disease to survive over winter.
Another contributing factor to the onset of dollar spot is mowing
the grass to too short a length in dry periods when there are slow
rates of grass growth. The lawn is more at risk from disease and
weed infestation at these times.
The disease is spread across the lawn by foot and vehicle traffic,
watering, rain and dew.
Treatment of dollar spot
As with nearly all lawn diseases prevention is better than the
cure and if you follow a good lawn care
programme then you should not be bothered by this problem.
Watering the lawn at the correct
intervals is one of the keys to preventing dollar spot as it will
help the soil retain moisture. Remember it is best to water thoroughly
at intermediate intervals rather than watering sparingly at short
You should aim to water the lawn in the morning as the grass should
be dry before nightfall so that optimum conditions for fungus growth
are avoided. Dispersal via water is one of the ways that the disease
travels across a lawn so watering should be done with care.
Removing / reducing the layer of thatch will help water penetrate
the lawn and reach the soil. Use a lawn scarifier every autumn to
dethatch the lawn.
Ensure your lawn has adequate nitrogen levels by applying a suitable
lawn fertiliser at the correct
As a last resort Fungicides are available for the treatment of
Because dollar spot can kill the whole of the grass plant you may
need to reseed areas of the lawn even if you have eradicated the