Beech trees at risk as new disease discovered in Europe after being unnoticed for 12 years

Helena Horton
A beech tree affected by the disease
A beech tree affected by the disease

Beech trees are at risk from a newly-discovered disease which has lain unnoticed in Europe for the past 12 years.

Research by the Forestry Commission has found that Petrakia liobae may have been present in Europe for at least 12 years but had previously gone unnoticed. 

The fungus causes leaves to have unsightly brown splotches and could pose a risk to young saplings.

The disease is relatively slow-spreading and unlikely to result in the death of mature trees, but experts warned that it reduces tree health and visual appeal, especially in newly planted trees.

Walkers have been urged to keep an eye out for trees with signs of the disease and report it to the Forestry Commission.

Simon Honey, from the Forestry Commission, said: "nfected trees develop brown, irregular leaf spots with sharp, dark borders. These necrotic spots are around 1-50mm in diameter and may merge in cases of heavy infection. Mature lesions may also have fluffy white propagules (detachable spores) associated with the leaf spot. Look for symptoms in the lower canopy (1.5m – 2mm from the ground) as the P. liobae overwinters in leaf litter and re-infects nearby beech trees in the spring."

The fungal pathogen was first discovered in Switzerland in 2008, followed by findings in Germany, Austria, Slovakia and most recently Slovenia in 2018. It was thought originally to be a fungal disease from Japan, but has now been found to be native to Europe.

The quick succession of these findings, along with their locations strengthen suggestions that the disease has probably been present in central Europe for a long time.

The disease has not yet been spotted in the UK but there are fears that imported trees could spread the fungus to our native Beech, as has happened with other diseases which have impacted trees including elm, ash and oak.

Mr Honey added: "The focus is on younger hedging specimens imported from central Europe. Due to the unsightly nature of the disease, infected stock is usually graded out during quality checks. However, there is the possibility that the disease is already present within the UK but remains undiscovered – as was the case in central Europe."