Sweet Chestnut Blight

Sweet Chestnut Blight in Devon

Posted on April 12, 2017

Hot on the heels of the devastating news about Ash Dieback in the UK are recent reports of the spread of Sweet Chestnut Blight – with new cases being reported and quarantined areas set up here in Devon in Southwest England.

What is Sweet Chestnut Blight?

Sweet Chestnut Blight is a fungal disease caused by the pathogen Cryphonectria parasitica. Here in the UK this particular disease poses a huge threat to approximately 12,000 hectares of woodland where Sweet Chestnut (Castanea sativa) is the dominant tree species. A large proportion of these spaces are located in the Southwest of the UK.

The disease was first identified in the UK in 2011 and there have been recent cases identified in 2016 and 2017 in Devon which highlight the spread and potential threat posed by the pathogen.

Introduced from Eastern Asia, Chestnut blight caused catastrophic losses to the tree population in North America in the early part of the 20th century and the disease has been tracked across Continental Europe since it was first identified in Italy in 1938.

Although often referred to as a ‘Chestnut’ – the Horse Chestnut or Conker Tree is unrelated to the Castanea and is unaffected. The blight can sometimes affect Oak trees where Sweet Chestnuts and Oaks are in close proximity but the pathogen is not fatal to Oaks and the damage is often minimal.

Recent Developments:

In early March 2017 the number of quarantined zones in Devon and the Southwest was increased to 4 after additional confirmed outbreaks. Initially 2 areas in Devon were affected – a zone around the Exe Estuary focusing on the village of Starcross and also an area of coastal North Devon between Ilfracombe and Braunton. The 2 new areas are an area around Willand in central Devon and also an area between Yeovil and Sherborne. There is a Prohibition in these areas.

What does Prohibition mean?

‘A prohibition makes it illegal to move sweet chestnut (Castanea sativa) material including plants, logs, branches, foliage and firewood out of, or inside, zones within a 5km radius of the sites, with a 1km radius for oak.’

You can find out more on the Forestry Commission Website.

Things to look out for when identifying Sweet Chestnut Blight:

Bright orange pustules are produced throughout the year on affected trees – most notable after wet weather in mild conditions.

Cankers (swollen or sunken) on stems, branches and trunks

Wilting of leaves/foliage

Dieback of the stems

Who to Contact if you believe you have identified Sweet Chestnut Blight:

Food and Environment Research Agency on 01904 465625 

or the Forestry Commission on 0131 314 6414.