Sweet chestnut blight is a destructive disease of sweet chestnut trees (trees in the Castanea genus) caused by the fungus Cryphonectria‘Cryphonectria parasitica.parasitica’.

ItSweet ischestnut regulatedblight asis a regulated quarantine pest in Greatthe Britain,UK, meaning it is under official control measures and cannot be introduced, moved, multiplied or released without prior authorisation.

It is not native to the UK, although it is now widespread in Europe. Since 2011, the disease has been found at a small number of sites in England, which are subject to statutory control measures.

Symptoms and identification

Sweet chestnut blight attacks the bark of sweet chestnut trees, entering through fissures or wounds. All symptoms on infected trees occur above ground.

The fungus canspreads spread so rapidly through infected bark,bark causing stems or branches to become girdledgirdled. –This meaningmeans the flow of nutrients is eventually cut off to the sections of the tree sections above the infection. This kills the tree above ground level, and the dead bark becomes visible as a sunken canker.

Orange fruiting bodies, which produce the spores that spread sweet chestnut blight are also visible on the bark. These erupt through lenticels (raised openings) and release long, orange-yellow tendrils of spores in moist weather.

When the canker girdles the stem leaves wilt and turn brown but remain hanging on the tree. Below the canker, branches retain healthy foliage and new shoots are produced after a short time. It is common to find many cankers on a single tree.

Young trees may die within a year of infection. Mature trees may take several years or more to decline and die. 

The fungus can occasionally affect some species of oak when they are growing in very close proximity to heavily infected sweet chestnut trees, especially when they are significantly stressed. The disease does not affect horse chestnut (conker) trees.

ReportHow to report sightings

SweetLook chestnutout blight has been found at a number of sites in the United Kingdom, principally in central and southern England.

Please remain vigilant for signs of sweet chestnut blight. If you think you have spotted signs of this disease anywhere in Great Britain, report it using using:

• TreeAlert.
  (Great Britain)
• Treecheck (Northern Ireland)

ReportRefer suspectedto sightingsForest inResearch’s Northernmaps Irelandof usingconfirmed Treechecklocations, which shows sweet chestnut blight has been found at many sites in the all-IrelandUK. treeMostly pestin reportingcentral tool.and southern England.

If you trade in plants in England or Wales and suspect sweet chestnut blight on your site, please contact your local Animal &and Plant Health Agency (APHA)(APHA) plant health and seeds inspector or contactemail planthealth.info@apha.gov.uk.

ManagementHow to manage infected trees or sites

Sweet chestnut blight is a notifiable plant disease. If you suspect it, you must be report it immediately to the relevant plant health authorityauthority. –Do do not wait for confirmation before doing so.

YouDo must not destroy or move any infected plants, bark or wood unless you have been instructed to do so by the Forestry Commission or APHA.APHA.

Demarcated area restrictions apply to parts of England where specific controls are in place to prevent spread. Read more and refer to the demarcated area map.

RegulationImport restrictions and regulations

Cryphonectria parasitica is a regulated pest in the UK. Import restrictions apply to  sweet chestnut material from all third countries outside the UK, including plants for planting, wood and bark. These restrictions are intended to minimise the risk of further introductions of the disease.

UK legislation also requires the use of UK plant passports for the movement of all Castanea species, including sweet chestnut, with bark and isolated bark of these species.

Plant health notice (sweet chestnut blight)

ToThe protect England against sweet chestnut blight, the Forestry Commission has introduced a demarcated area around the Devon outbreak site under powers conferred by The Official Controls (Plant Health and Genetically Modified Organisms) (England) Regulations 2019.

DemarcatedSweet Areachestnut No.1blight Noticenotice comesno.2 came into force 226 AprilAugust 2026 and applies to the partsareas ofin Devon and Cornwall within the boundaries showndescribed in the notice and describedshown in the notice.‘Sweet chestnut blight demarcated area map’:

Sweet chestnut blight notice 19 August 2026 (PDF, 725 KB, 5 pages)

The notice:

• restricts the felling or killing of any trees of the genus Castanea without prior notification to the Forestry Commission
• restricts the movement of materials capable of spreading the disease both within and out of the demarcated area, including wood, chips and isolated bark

Provision is made within the notice to enable plant health inspectors to authorise movements and processing of material from the demarcated area where this can be achieved without risking the spread of sweet chestnut blight.

Landowners must provide notice of their intention to fell relevant material at least 30 days in advance of any felling in the demarcated areas. Felling may only commence once written authorisation is provided the Forestry Commission.

You can refer to the previous notice sweet chestnut blight notice 1 (March 2026) and previous demarcated area map (March 2026).

Contact us

ForEmail us at sweetchestnutblight.authorisation@forestrycommission.gov.uk for all enquiriessweet pleasechestnut contactblight sweetchestnutblight.authorisation@forestrycommission.gov.ukqueries.

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