UK Risk Register Details for Adelges tsugae

Common Names

  • Hemlock chermes
  • Hemlock Woolly Adelgid

Scenario and Pathways

Scenario for Risk Register

  • show / hide
  • Pest is introduced

Pathway Assessed for Entry to UK

  • show / hide
  • Plants for planting (except seeds bulbs and tubers)

Common Pathways

  • show / hide
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] 3
Spread [1 - 5] 3
Impact [1 - 5] 5
Value at Risk [1 - 5] 2
Likelihood x Impact [1 - 25] 15
UK Relative Risk Rating [1 - 125] 30

Current Mitigations

  • show / hide

Key mitigation for pest

EU prohibition of key pathway



Industry Scheme

Contingency Plan



Mitigated Risks

Likelihood [1 - 5] 1
Spread [1 - 5] 3
Impact [1 - 5] 5
Value at Risk [1 - 5] 2
Likelihood x Impact [1 - 25] 5
UK Relative Risk Rating [1 - 125] 10

Proposed Actions

Proposed Actions



Management By Industry

Targeted Survey


Contingency Plan



Distribution and Pest Details


Country Status Notes
United Kingdom Absent
North America
Canada Present (Limited)
United States Present (Limited)
China Present
India Present
Japan Present
Taiwan Present

Type of Pest

  • Insect (Hemiptera)

Host or Industry at Risk

  • show / hide

Arboretum or ornamental trees

Major Hosts

  • Picea polita (Sieb. & Zucc.) Carr.
  • Tsuga canadensis (L.) Carr.
  • Tsuga diversifolia (Maxim.) Mast.
  • Tsuga sieboldii Carr.

Threats to Protected Cultivation

Forest Tree Pests and Pathogens

  • Coniferous

Further Information

PRA Availability

PRA not available

EU and EPPO Listing

Not currently listed

Actions Indicated

  • show / hide


No current Actions Indicated

General Comments

Pest of Tsuga and Picea with limited effects in its native range, but which has been very damaging to Eastern Hemlock in North America. Prohibition in place to prevent entry of susceptible tree species from outside Europe. Sentinel project will be helpful in monitoring developments elsewhere.

Risk Records for this Pest