Pest or disease?
Disease 

Causal agent:
Unknown, potential association with pathogenic nematode Litylenchus crenatae mccannii

Host trees:
Mainly American beech but symptoms also found on other beech species

Present in the UK?
No

Tree Alert required?
Yes

Beech leaf disease is a newly described disease causing discolouration of beech leaves. 

Beech leaf disease was first observed in Ohio in 2012 and is now found across Eastern USA and Canada. It mainly affects American beech, however symptoms have been observed on other beech species such as European beech and Oriental beech. As a newly described disease the risk to other beech species, the disease biology, and pathogens associated require further research.  

The pathogenic nematode Litylenchus crenatae mccannii has been found in association with beech leaf disease symptoms, however the disease mechanism requires further research. Symptoms include; dark banding and yellowing between the veins of leaves, leaves becoming curled, deformed and shrivelled, premature leaf drop, aborted buds and a thinning canopy. Reduction in canopy can result in death of mature trees in ten years. Observatree is involved in a project with Fera Science Ltd, volunteers collect beech leaves annually for testing for the pathogenic nematode. For more information on beech leaf disease please see the resources below.