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What attacks birch: pests and diseases the sources name

A register of the borer, the rust and canker fungi, the root rot and the longhorned beetle that Canadian, British and US sources tie to birch: which birches 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. Birches are covered species by species in tree species in the agency records, including paper birch, river birch, sweet birch, silver birch and downy birch.

The register

AgentWhat the sources record
Bronze birch borer, Agrilus anxius. Full profileKind: Wood-boring beetle
Hosts: Natural Resources Canada says it is a specialist on all native and introduced birches in Canada, found commonly on white birch, and that introduced European white birch appears highly susceptible. The Morton Arboretum sorts birches by susceptibility: Himalayan, European white and moor birch highly susceptible; yellow, sweet, paper and gray birch showing some resistance; river birch rarely affected.
Where and status: Native to North America. Natural Resources Canada says planting of introduced birches in cities has extended its range to western and southern North America, and Oregon State University Extension describes birches dying from it in the Pacific Northwest. No page gives a regulated status in Canada, the United States or the United Kingdom. Natural Resources Canada says the European Union declared it a quarantine pest.
Season: Natural Resources Canada says adults emerge over about 6 weeks from May to July. The Morton Arboretum says females lay eggs in cracks in the bark in late May or June, and the larvae tunnel through summer into fall. One generation a year in the south of the range and two years in cooler regions or in vigorous trees, according to Natural Resources Canada.
Birch rust, Melampsoridium betulinum, and canker fungi Discula betulina and Marssonina betulaeKind: Rust fungus and two canker fungi
Hosts: Forest Research says the rust matters on birch in several European countries, where it goes with slower height growth and more deaths. It names the two canker fungi in the dieback of silver birch, and says provenance may be a key factor in susceptibility.
Where and status: The entry for downy birch says widespread and gradual dieback of birch occurs in some areas, especially in young trees 5 to 10 years after planting. It gives no regulated status for these fungi.
Season: No season given on the page read.
Armillaria root rot (honey fungus). Full profileKind: Root-rotting fungus
Hosts: Forest Research rates the genus Betula as very susceptible to it.
Where and status: The Forest Research entry for downy birch names it without a place or status. The profile linked here sets out the agency records for the fungus itself.
Season: No season given on the page read.
Asian longhorned beetle, Anoplophora glabripennis. Full profileKind: Wood-boring beetle
Hosts: The Canadian Food Inspection Agency says birch, poplar and willow are occasionally affected, with maple the group most likely to be affected. Forest Research lists birch (Betula) among known hosts.
Where and status: The Canadian agency says it was eradicated from Mississauga and Toronto in 2020. Forest Research lists it as not present in the United Kingdom and notifiable.
Season: No season given on the pages read for birch.

How the sources describe the effects

The Morton Arboretum says the first warning sign of bronze birch borer is yellowing and thinning of foliage in the upper crown, followed by dieback of the upper branches, and that an infestation can move down the tree and kill it in two to three years. It says the adult beetle feeds only briefly on leaves, and that the damage comes from larvae tunnelling under the bark and cutting off water flow. Natural Resources Canada describes adults leaving D-shaped exit holes and says the beetle generally attacks older and stressed trees, with outbreaks becoming more frequent in periods of widespread birch decline perhaps linked to stress such as drought, age-related senescence and spring thaw-freeze events. Oregon State says a D-shaped exit hole is a certain indicator of buprestid beetles like this one but that other signs, such as a dead branch or stained bark, can come from other causes.

The fungal side is different. Forest Research ties the dieback of silver birch to the two canker fungi, links the rust to slower height growth and more deaths, and says climate also plays a part.

Profiles on this site

The full profiles linked in the table are bronze birch borer, Armillaria root rot and Asian longhorned beetle. The birch rust and canker fungi have only the row above, because the page read gives too few separate facts for a page each. The agency record for the birch the sources call downy birch in Britain is on the downy birch page.

Who the sources say to report to

The Canadian Food Inspection Agency asks that Asian longhorned beetle or signs of it be reported to the agency immediately. Forest Research asks that suspected cases of notifiable pests, including that beetle, be reported in mainland Britain through TreeAlert. The pages read for bronze birch borer and for the birch fungi name no report line. The reporting offices for each country are on the report a pest in Canada and report a pest in the United Kingdom pages.

Sources