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UK Risk Register Details for Phytophthora alni

Pest has been archived

This pest has been assessed for the Risk Register and is considered to pose a low risk to the UK. The information on this pest was correct as of 20/05/2020, but is no longer actively maintained. It will only be updated if new information is received which indicates the potential for a significant increase in risk to the UK.

This record was last updated on 08/06/2022

Common Names

  • Alder bleeding canker
  • Alder Phytophthora root disease

Scenario and Pathways

Scenario for Risk Register

  • show / hide
  • Pest spreads to maximum extent

Pathway Assessed for Entry to UK

  • show / hide

Common Pathways

  • show / hide
  • Plants for planting (except seeds bulbs and tubers)
  • Soil/growing medium
  • Natural spread

Risk Ratings and Current Mitigations

Unmitigated Risks

Likelihood [1 - 5] 4
Spread [1 - 5] 4
Impact [1 - 5] 4
Value at Risk [1 - 5] 3
Likelihood x Impact [1 - 25] 16
UK Relative Risk Rating [1 - 125] 48

Current Mitigations

  • show / hide

Key mitigation for pest



Industry Scheme

Contingency Plan



Mitigated Risks

Likelihood [1 - 5] 4
Spread [1 - 5] 4
Impact [1 - 5] 4
Value at Risk [1 - 5] 3
Likelihood x Impact [1 - 25] 16
UK Relative Risk Rating [1 - 125] 48

Proposed Actions

Proposed Actions



Management By Industry

Targeted Survey


Contingency Plan



Distribution and Pest Details


Country / Territory Status Notes
United Kingdom Present (Widespread)
Austria Present
Belgium Present
Czech Republic Present
France Present
Germany Present
Hungary Present
Ireland Present
Italy Present
Lithuania Present
Netherlands Present
Poland Present
Slovakia Present
Slovenia Present
Spain Present
Sweden Present
Latvia Present
Belarus Present
North America
United States Present (Limited)

Type of Pest

  • Oomycete

Host or Industry at Risk

  • show / hide


Major Hosts

  • Alnus Mill.
  • Alnus cordata (Loisel.) Loisel./Desf./Duby
  • Alnus glutinosa (L.) Gaertn.
  • Alnus incana (L.) Moench
  • Alnus viridis (Chaix) Dc.

Threats to Protected Cultivation

Forest Tree Pests and Pathogens

  • Broadleaved

Further Information

PRA Availability

PRA not available

Regulation and EPPO listing

  • show / hide

Not currently listed

Actions Indicated

  • show / hide


No statutory action against findings. Actions to be considered alongside those for Alder rust, including value of any surveillance or changes to Forestry Commission grant-aid for planting.

General Comments

Damaging pathogen of alder, first detected in the UK in 1993, which has subsequently spread to most areas of the UK. Alders are important in the context of watercourse management. No prospect of eradication or containment but possible co-ordinated action to mitigate impacts to be considered with stakeholders.

Risk Records for this Pest