Mapping the Distribution of Phytophthoras in Britain

Phytophthoras are a group of microscopic fungal pathogens responsible for major plant diseases in many parts of the world, although prior to the 1990s they had relatively little impact in European woodlands. However, over the past two decades this has changed markedly and our aim is to improve understanding of the distribution of Phytophthora species in Britain and the trees they affect.

Research objectives

This project aims to analyse past and current records generated from various Forest Research projects and the Tree Health Diagnostic & Advisory Service  to plot the distribution of the most damaging and best known species in Britain.

Specific objectives are to:

  • Build spatial maps showing the distribution of a range of Phytophthora species.
  • Show the host range of each mapped Phytophthora species, indicating the most common and least common tree hosts.
  • Use the records, behavioral traits of each Phytophthora, and climatic data to predict how distribution may change in the future.

Results so far

Over 3,000 Forest Research records for Phytophthoras which date from 1975 to the present day have been analysed as a precursor to mapping. First draft distribution maps have now been generated for ten Phytophthora species frequently encountered in Britain. These are:

More recently, other less well known Phytophthora species including P. siskiyouensis, P. foliorum and P. gallica have also been found in Britain and research is underway to learn more about their behaviour and potential hosts.


This project started the 1st April 2015 and is ongoing


Joan Webber

Funders and partners

This project is funded jointly through Horizon 2020 and the Forestry Commission as part of the research programme Understanding Threats to Resilience

The research is in line with support to government policies of sustainable forest management as laid out in The UK Forestry Standard and its supporting series of Guidelines.