Ash dieback was first identified in the UK in 2012. The disease is well established throughout mainland Europe, where it is responsible for losses of commercial and amenity tree planting.
Spread by a fungus called Hymenoscyphus fraxineus, the disease is often simply referred to as ‘ash dieback’ due to the symptoms on infected trees: leaf loss, crown dieback and bark lesions.
Once infected, trees are likely to die either as a direct result of the disease or will succumb to other diseases. Three tree and shrub species in the same family (Oleaceae) as ash, including mock privet, narrow-leaved mock privet and white fringe tree are also susceptible to the disease.