Our native ash trees may be affected by a range of disorders whose symptoms often mirror those of ash dieback. Therefore, careful observation of symptoms of suspected dieback is necessary to avoid getting diagnosis wrong.
The Forestry Commission disease identification guide Tree Alert takes users through a key of symptoms to a refined diagnosis.
Common reasons for wrong diagnosis of Ash dieback
- Perennial target cankers may at first glance seem similar to the sunken lesions of ash dieback and patchy crown dieback due to honey fungus may also lead to initial misdiagnosis.
- Ash trees are extremely sensitive to temperature fluctuations and severe winters or late frosts can cause similar symptoms developing as with dieback. Conversely, sparse foliage can be caused by mild winters failing to break dormancy and drought stress can lead to crown dieback.
- The as yet unreported Emerald Ash Borers and Asian Longhorn Beetles both by their tunnelling actions in the phloem lead to similar symptoms of crown decline and epicormic attempts at rejuvenation.
- Human actions of pesticide overspray or deep plough damage can lead to discoloured foliage or crown dieback.