What attacks beech: pests and diseases the sources name
A register of the nematode, the scale-and-canker complex, the root and decay fungi and the squirrels that Ontario, New York, Maryland and Forest Research sources tie to beech: which beeches each page names, where it is recorded, the season each source mentions, and where the full profile is.
Checked against the sources at the bottom of this page on October 9, 2026. Rules, fees and pay change: the source has the last word.
This page reports what the named sources say. It is not a diagnosis of any tree and does not say what should be done with one. Each row names its source, all read on October 9, 2026. Where this site has a full profile, the row links it, and the regulated status tables are on the linked pages and are not repeated here. Beech is covered in common beech, from the British and European forestry bodies.
The register
| Agent | What the sources record |
|---|---|
| Beech leaf disease, Litylenchus crenatae mccannii. Full profile | Kind: Nematode, a microscopic worm Hosts: Ontario says it is found in forests with American beech and in plantings of European, Oriental and Chinese beech in North America. The University of Maryland Extension says native beech and non-native varieties such as European beech are susceptible. Where and status: Ontario says it was first detected there in 2017 and is present in the lower half of southern Ontario. Maryland says it was first documented in 2012 in Lake County, northeastern Ohio, and has spread to nine states and Ontario. Neither page gives a regulated status. Season: New York State says leaf symptoms can show from leaf-out in May until leaves fall in October. Ontario says nematodes feed on developing buds in fall and spring, increase in number from spring to fall and overwinter in buds and leaf litter. |
| Beech bark disease, beech scale Cryptococcus fagisuga with the canker fungus Neonectria faginata | Kind: Insect-and-fungus complex Hosts: Ontario says it is found on American and European beech, most often in mixed forests with sugar maple and hemlock present. Where and status: Ontario calls it invasive, native to Europe, and says it is advancing through much of the range of beech in the province. New York State says it is common across the state and not managed by its Department of Environmental Conservation. Neither gives a regulated status. Season: Ontario says small orange-red fruiting bodies are produced in late summer and fall, and that lag times between scale infestation and fungal infection range from about 2 to 10 years. |
| Phytophthora, Meripilus, Ganoderma and Armillaria. Phytophthora profile, Ganoderma profile, Armillaria profile | Kind: Root-rot and decay fungi and water moulds Hosts: Forest Research says beech is susceptible to a wide range of pests and diseases including these, and that many are secondary issues that occur where trees are stressed. Where and status: The entry covers Britain and gives no regulated status for these. Season: No season given on the page read. |
| Grey squirrel bark stripping. Squirrel damage profile | Kind: Mammal Hosts: Forest Research calls beech highly vulnerable to bark stripping by grey squirrels, and says the species is highly palatable to all browsing mammals, with rabbits able to damage the lower stem of young trees. Where and status: Britain. No regulated status. Season: Forest Research puts the risk highest for trees aged 10 to 50 years and after a thinning, when the bark strips more easily. |
How the sources describe the effects
Ontario describes both diseases as deadly. Beech leaf disease causes leaf deformity in beech of all ages, with sapling-sized trees dying within 2 to 5 years and older trees taking longer. The University of Maryland Extension gives 2 to 7 years from infection to death. For beech bark disease Ontario says feeding punctures from the scale kill the living bark and let the fungus in, causing severe cankering, stem deformation and eventually death, usually of large trees first. New York State says most trees die within 10 years of infestation by the insect and fungus.
The sources also separate the look-alikes. New York State lists beech bark disease, erineum patch (caused by eriophyid mites and not typically viewed as a problem) and powdery mildew as other things seen on beech, and says a tree can show beech leaf disease alongside any of them. Forest Research calls the squirrel the biggest threat to growing beech successfully in Britain, ahead of the fungi.
Profiles on this site
The full profiles linked in the table are beech leaf disease, Phytophthora root rots, Ganoderma, Armillaria root rot and tree squirrel damage. Beech bark disease has only the row above, because the pages read give too few separate facts for a page of its own.
Who the sources say to report to
The Forest Research beech entry points to TreeAlert for reporting a suspected case and names no notifiable agent. New York State says it is interested in reports of leaf striping or curling on any beech, and does not manage the other issues in its look-alike table. Ontario names no report line on its two pages. The reporting offices for each country are on the report a pest in Canada, report a pest in the United States and report a pest in the United Kingdom pages.
Sources
- Government of Ontario, Beech leaf disease (updated August 28, 2025), read October 9, 2026
- Government of Ontario, Beech bark disease (updated June 11, 2025), read October 9, 2026
- New York State Department of Environmental Conservation, Beech Leaf Disease, read October 9, 2026
- University of Maryland Extension, Beech Leaf Disease (updated October 21, 2024), read October 9, 2026
- Forest Research, tree species database entry for beech (BE), read October 9, 2026