UK Risk Register Details for Candidatus Phytoplasma asteris in Potato

Common Names

  • Aster yellows
  • AY
  • yellow disease phytoplasmas

Scenario and Pathways

Scenario for Risk Register

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  • Pest is introduced

Pathway Assessed for Entry to UK

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  • Plants for planting (except seeds bulbs and tubers)

Common Pathways

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This section is currently being developed as part of the next phase of the Risk Register.

Risk Ratings and Current Mitigations

Unmitigated Risks

Likelihood [1 - 5] 4
Spread [1 - 5] 3
Impact [1 - 5] 3
Value at Risk [1 - 5] 5
Likelihood x Impact [1 - 25] 12
UK Relative Risk Rating [1 - 125] 60

Current Mitigations

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Key mitigation for pest

EU regulated pest and prohibition of key pathway



Industry Scheme

Contingency Plan



Mitigated Risks

Likelihood [1 - 5] 2
Spread [1 - 5] 3
Impact [1 - 5] 3
Value at Risk [1 - 5] 5
Likelihood x Impact [1 - 25] 6
UK Relative Risk Rating [1 - 125] 30

Proposed Actions

Proposed Actions



Management By Industry

Targeted Survey


Contingency Plan



Distribution and Pest Details


Country Status Notes
United Kingdom Absent
North America
Mexico Present
United States Present
China Present

Type of Pest

  • Phytoplasma

Host or Industry at Risk

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Solanum tuberosum

Major Hosts

  • Solanum tuberosum L.

Threats to Protected Cultivation

Forest Tree Pests and Pathogens

Further Information

PRA Availability

PRA not available

EU and EPPO Listing


Actions Indicated

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Statutory action against findings. A survey to assess the distribution of Ca. Phytoplasma asteris in the UK and which sub-groups are present. Research into whether UK isolates infect potatoes.

General Comments

Phytoplasma pest with a wide host range, present in the UK, elsewhere in Europe and beyond. Not known to infect potato crops in Europe and import prohibitions effectively mitigate the risk of further introductions by this means.Uncertainty about the risk to potatoes are not infected and the role of vectors.