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UK Risk Register Details for Pityophthorus juglandis

This record was last updated on 28/11/2022

Common Names

  • Walnut Twig Beetle

Scenario and Pathways

Scenario for Risk Register

  • show / hide
  • Pest is introduced with the pathogen

Pathway Assessed for Entry to UK

  • show / hide
  • Plants for planting (except seeds bulbs and tubers)
  • Non-squared wood

Common Pathways

  • show / hide
  • Plants for planting (except seeds bulbs and tubers)
  • Non-squared wood
  • Wood packaging material
  • Firewood

Risk Ratings and Current Mitigations

Unmitigated Risks

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

Current Mitigations

  • show / hide

Key mitigation for pest

Regulated quarantine pest



Industry Scheme

Contingency Plan



Mitigated Risks

Likelihood [1 - 5] 2
Spread [1 - 5] 3
Impact [1 - 5] 4
Value at Risk [1 - 5] 1
Likelihood x Impact [1 - 25] 8
UK Relative Risk Rating [1 - 125] 8

Proposed Actions

Proposed Actions



Management By Industry

Targeted Survey


Contingency Plan



Distribution and Pest Details


Country / Territory Status Notes
Italy Present Present, under eradication
France Present (Limited) Transient, actionable, under eradication.
United Kingdom Absent
North America
Mexico Present
United States Present (Limited)

Type of Pest

  • Insect (Coleoptera)

Host or Industry at Risk

  • show / hide


Major Hosts

  • Juglans ailanthifolia var. ailanthifolia Carr.
  • Juglans californica Wats.
  • Juglans cathayensis Dode
  • Juglans cinerea L.
  • Juglans hindsii Jeps. Ex R.E.Smith
  • Juglans major (Torr.) Heller
  • Juglans mandshurica Maxim.
  • Juglans microcarpa Berlandier
  • Juglans mollis Engelm.
  • Juglans nigra L.
  • Juglans regia L.
  • Juglans
  • Pterocarya Kunth
  • Pterocarya fraxinifolia (Lam./Poir.)Spach
  • Pterocarya rhoifolia Sieb. & Zucc.
  • Pterocarya stenoptera C.Dc.

Threats to Protected Cultivation

Forest Tree Pests and Pathogens

  • Broadleaved

Further Information

PRA Availability

PRA not available

Regulation and EPPO listing

  • show / hide

Regulated quarantine pest, EPPO A2

Actions Indicated

  • show / hide


Statutory action on findings.

General Comments

Insect (which vectors a fungal pest) which together cause ‘thousand cankers disease’ and mortality of walnut in the US and elsewhere. Black walnut is not widespread in the UK but the main walnut species (Juglans regia) is also susceptible. A watching brief will be maintained on the current outbreak in Italy. Industry should also be aware.

Risk Records for this Pest