New tree disease affecting St Helena’s endemic trees

St Helena Government has been collaborating with its project partners at the Centre for Agriculture and Bioscience International (CABI) and the Birmingham Institute of Forest Research (BIFoR) at the University of Birmingham since April 2021 to implement the Darwin Plus funded project ‘Managing the pathogens threatening St Helena’s biodiversity and food security’.

What’s happening?

Through recent surveys on the Peaks and in other areas where endemic trees are growing, it has been found that a number of trees appear to be dying as a result of Phytophthora infection. Phytopthora is a water mould which looks and behaves like a fungus, despite not actually being a fungus.

It is spread via water, and can be carried by the movement of water through soil (during periods of high rainfall) and movement of contaminated soil (e.g. the mud on boots, equipment and vehicles) or from the movement of plants.

There are many different species of Phytopthora that are known to have a devastating effect on trees and crops around the world. On St Helena farmers might have come across the scientific name because Phytopthora infestans is a disease known to affect potatoes, and its common name is late blight.

St Helena is not alone in being affected by tree disease. The increase in ability to detect and record new species; the increase in trade in plants; the increase in movement of invasive species; the increased movement of people and access to the countryside and climate change are all contributing to the increase in reporting of plant disease around the world. In the UK Phytophthora ramorum is killing larch trees and in America it is the cause of sudden oak die back.

We don’t know which species of Phytophthora is affecting the endemic trees yet but it is now considered beyond reasonable doubt that it is the cause of tree death in some trees. The discovery of Phytopthora on St Helena is very significant, but we don’t yet know if it is the only pathogen causing to tree death.

What are we doing?

The early warning of the presence of Phytophthora and its spread is being treated seriously and the Environment, Natural Resources & Planning Portfolio has established a small Task Group to secure further information on species of Phytophthora, learn more about the range of species affected and the area over which infection occurs, and to develop and implement a rapid response to reduce the rate and risk of spread of the pathogen 

Stopping the spread of the disease is the most important thing to be done at this stage, and unfortunately people are one of the best ways to carry the infection from one area to another.

As a result of identifying Phytopthora in sensitive conservation sites that hold unique and rare biodiversity which are now at risk, a number of restrictions will be implemented with regards to access to the Peaks and areas of endemic planting.

As a first step, the George Benjamin Arboretum, She Cabbage and False Gumwood gene bank at Casons (near the carpark), and the Ginger Patch at High Peak, will be closed to public access with immediate effect and foot washing stations will be installed across the Peaks. 

What can you do?

It is important that when and wherever you walk on St Helena you keep to the paths, and especially so in the Peaks National Park where the disease is most prevalent.

Footbaths for washing shoes and boots will be installed at the entrances to the National Park, and within it, so that all visitors to the Park can wash their boots on the way in, during their visit and on the way out. This will help to reduce the risk of spreading the disease within the Peaks and beyond.

The public are asked to give their full co-operation to all disease notices and signs where restrictions are required. Further information and guidance will be provided to the public shortly.

For further information in the meantime, please contact ENRP Portfolio Director, Darren Duncan, at or on telephone via 24724.

#Phytopthora #CABI


10 November 2022

St Helena Government Communications Hub

Telephone: 22470