Chalara dieback of ash in Great Britain.
You'll probably have seen in the press or on television or heard on radio that there is a
serious fungal disease of ash trees that has appeared in Britain probably brought from
continental Europe where the disease has caused the widespread death of ash. Articles in
papers such as the Sunday Times have called it a threat equivalent to the outbreak of the
virulent Dutch Elm disease in the 1960s and 70s but as ash occurs in both woodland and
hedges, unlike elm that was more common in hedges, the potential change to our
landscape is much greater.
The disease causes leaf loss and crown dieback. Unfortunately the symptoms for
Chalara may also be caused by other ash problems; physical damage, other fungi
and a bud moth as well as frost damage so viewing the pictures on the F.C. website
We need to be very vigilant about the disease it seems to be spreading fast
although at the moment its nearest point to us is just north of Watford it could
easily and rapidly spread though the mechanism for this is not yet understood. The
Forestry Commission are treating the disease very seriously and will use statutory
plant health notices to enforce its control as well as prevent movement of ash
seeds and plants.
The Forestry Commission has produced information sheets and a pictorial guide to
the symptoms of the disease caused by a fungus called Chalara fraxinii and these
are available at www.forestry.gov.uk/England – Chalara. To report the disease the
number for the Forestry Commission is 0117 3721070.
Ash dieback progress.
The University of Exeter and a consortium of other universities and organisations in
the UK and in Europe have been granted money for research on the fungus that
causes Ash dieback. This research will examine the genes of Ash trees to find out
how susceptible and resistant trees differ, the interaction between the fungus and
trees and help develop effective control strategies. At present little is known about
the fungus and why it is so aggressive. The aim is to get research underway very
quickly so the results can be applied to help save our third most common broadleaf
It is hoped this research might also help understand fungal diseases affecting a
range of trees and other plants.
It looks as if in 2019 we will see a major loss of Ash trees in Dorset as many are
already showing poor development of new leaves. It is estimated that up to 80% of
ash trees will be lost but if 20% survive they will hopefully be resistant to the
fungus and will in time the off spring of these will replace the losses. Dont fell ash
before they show signs of the disease as they may be among the resistant ones!