EPPO Platform
on PRAs

Express PRA for Citrus bark cracking viroid


Overall assessment of risk: The occurrence of CBCVd on hop presents an exemplary case of transmission of a less significant viroid on citruses to a new host, causing severe disease and high economic loss. 

The likelihood of entry is estimated as moderate because the import of citrus plants is prohibited in most EPPO countries. Fruits of citruses are a very suitable entry pathway, and there is trade. Establishment is likely, where host plants are grown in the EPPO region, and CBCVd is already present in some citrus growing countries in the Mediterranean basin and in hop in Slovenia. 

Risk of spreading of CBCVd into hop growing areas is evaluated as low, when good agronomic practice measures are implemented, as well as appropriate handling of organic (citrus fruit) waste. In case of noncompliance with these measures in hop growing areas, the risk may increase. There is limited trade in hop plants for planting between countries. Hop growing areas are not interfering with citrus growing areas. There is a low possibility for spreading of CBCVd from citrus growing areas to hop growing areas. 

In case of transmission to hop, local rapid spread of CBCVd is possible through intensive and specific hop cultivation that provides ideal conditions for mechanic transmission at the time of vegetation. The EWG considered that potential impact in the absence of phytosanitary measures for hop would be high.


  • Citrus bark cracking viroid


  • Humulus lupulus


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Pest Risk Analysis Download 856,74kB

PRA Area

  • Slovenia