Reviewed September 2026
Sweet chestnut blight is a disease caused by the fungus Cryphonectria parasitica. It damages the bark of sweet chestnut trees and can cause branches or whole trees to decline. It does not affect horse chestnut trees, also known as conker trees. GOV.UK
Signs of sweet chestnut blight
Look for cracked or sunken areas of bark, known as cankers. Small orange growths can appear on the bark. Leaves above an affected area might wilt, turn brown and remain attached to the branch. New shoots sometimes grow below the damaged area. Other tree problems can cause similar symptoms, so appearance alone does not confirm the disease. GOV.UK
What should you do if you suspect it?
Report a suspected case promptly through Forest Research’s TreeAlert service. Do not move or dispose of material you believe is infected, including wood and bark, unless the Forestry Commission or Animal and Plant Health Agency instructs you to do so. GOV.UK
If you are concerned about the safety or condition of a sweet chestnut tree, contact ICS Tree Services. We can discuss the tree with you and advise on the next steps. Please report suspected blight through TreeAlert even if you also contact us.
Check the latest movement restrictions
The movement rules described in our original 2017 article are out of date. The Forestry Commission introduced updated restrictions in 2026 for specified areas of Devon and Cornwall. Boundaries and requirements depend on the current plant health notice. Before felling a sweet chestnut tree or moving material from an affected area, check the Forestry Commission’s latest guidance and map. GOV.UK
For more photographs and identification advice, see Forest Research’s sweet chestnut blight guide.