UK Risk Register Details for Diaspidiotus perniciosus

Common Names

  • Californian scale
  • Pernicious scale
  • San Jose scale

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] 5
Spread [1 - 5] 2
Impact [1 - 5] 2
Value at Risk [1 - 5] 5
Likelihood x Impact [1 - 25] 10
UK Relative Risk Rating [1 - 125] 50

Current Mitigations

  • show / hide

Key mitigation for pest

Special (outdated) EU regulation



Industry Scheme

Contingency Plan



Mitigated Risks

Likelihood [1 - 5] 2
Spread [1 - 5] 2
Impact [1 - 5] 2
Value at Risk [1 - 5] 5
Likelihood x Impact [1 - 25] 4
UK Relative Risk Rating [1 - 125] 20

Proposed Actions

Proposed Actions



Management By Industry

Targeted Survey


Contingency Plan



Distribution and Pest Details


Country Status Notes
Europe Present
Albania Present
Austria Present
Bulgaria Present
Switzerland Present
Czech Republic Present
Germany Present
Spain Present
France Present
United Kingdom Absent
Greece Present
Croatia Present
Hungary Present
Italy Present
Moldova Present
Netherlands Present
Poland Present
Portugal Present
Romania Present
Serbia Present
Russia Present
Sweden Present
Slovenia Present
Slovakia Present
Turkey Present
Ukraine Present
North America Present
Canada Present (Limited)
Cuba Present
Mexico Present
United States Present (Limited)
South America Present
Argentina Present
Bolivia Present
Brazil Present
Chile Present
Ecuador Present
Peru Present
Paraguay Present
Uruguay Present
Venezuela Present
Oceania Present
Australia Present
New Zealand Present
Africa Present
Congo (Democratic Rep.) Present
Algeria Present
Morocco Present
Tunisia Present
South Africa Present
Zimbabwe Present
Asia Present
Afghanistan Present
Azerbaijan Present
China Present
Georgia Present
India Present
Iraq Present
Iran Present
Japan Present
Kyrgyzstan Present
North Korea Present
South Korea Present
Nepal Present
Pakistan Present
Tajikistan Present
Uzbekistan Present
Vietnam Present

Type of Pest

  • Insect (Hemiptera)

Host or Industry at Risk

  • show / hide

Orchard crops, Ribes, Rubus

Major Hosts

  • Malus Mill.
  • Morus L.
  • Prunus L.
  • Pyrus L.
  • Ribes L.
  • Rubus L.
  • Vaccinium L.

Threats to Protected Cultivation

Forest Tree Pests and Pathogens

Further Information

PRA Availability

UK (2009)

EU and EPPO Listing

Council Directive 2006/91/EC, EPPO A2

Actions Indicated

  • show / hide


No current Actions Indicated

General Comments

One of 3 organisms regulated only though there own free standing Directives, and therefore subject to EU discussion to regularise. UK PRA and consultation concluded deregulation could be supported but more precautionary approach might retain some control on planting material.

Risk Records for this Pest