Trade restrictions on conifer trees have been lifted across seven English counties today (Wednesday 4 March) after a review that concluded the tree disease Phytophthora pluvialis no longer meets the criteria for quarantine pest status.
Demarcated areas in Cornwall and Devon, Cumbria, Herefordshire, Surrey, Gloucestershire and Shropshire have been revoked with immediate effect, enabling the unrestricted movement of affected conifer species for the forestry and plant trade sector.
Phytophthora pluvialis is a fungus-like pathogen primarily affecting Douglas fir and Western hemlock. It was first identified in Great Britain on Western hemlock in Cornwall in September 2021, the first finding of the pathogen in Europe, and precautionary measures were introduced placing movement restrictions on affected areas.
The decision to lift restrictions follows four years of scientific study primarily undertaken by Forest Research to better understand the risk of the disease. Taken together with surveillance data that confirmed no positive findings had been identified at any nursery sites in the restricted areas, the UK’s Plant Health Risk Group concluded the disease poses a low environmental and economic risk.
Demarcated areas in Scotland and Wales will also be lifted, reflecting a coordinated GB-wide approach to plant health policy.
Professor Nicola Spence, Defra Chief Plant Health Officer, said
“This is a positive outcome for the forestry and plant trade sector, and underlines the importance of our robust, evidence-led plant health surveillance and research programmes.
“When this was first identified in Great Britain in 2021 there were significant uncertainties regarding its impact. Four years of Defra-funded research have shown Phytophthora pluvialis does not pose the level of risk to justify continued quarantine measures and has allowed us to now reassess the risk of this pathogen.
“However, we urge continued vigilance and cooperation from the public and trade by reporting any suspected findings via TreeAlert.”
Andrea Deol, Forestry Commission Head of Plant Health Forestry, said
“Following four years of detailed research and surveillance, we are pleased to confirm that demarcated area restrictions across the affected counties in England have been revoked.
“I would encourage woodland owners to continue to look for signs of this disease and follow good biosecurity practices to reduce the risk of spread of pests and diseases to help us continue to protect the country’s trees and woodland”.
Further information, including updated guidance, is available at GOV.UK.
Additional information
· Phytophthora pluvialis is a fungus-like pathogen primarily affecting Douglas fir and Western hemlock conifers.
· All six demarcated areas previously in place have now been revoked Cornwall and Devon, Cumbria, Herefordshire, Surrey, Gloucestershire and Shropshire.
· The UK Plant Health Risk Group is the scientific advisory body responsible for assessing the risk posed by plant pests and pathogens in Great Britain.
· Approximately 52 nurseries fall within the former demarcated areas; restrictions had previously affected around 21 which historically grew host plants.
· No positive detections have been recorded at any GB nursery site, including during targeted testing at nurseries within the demarcated areas, reducing the perceived risk of spread via the plant trade.
· The research also found that comparatively, the pathogen causes less severe symptoms than the regulated pathogen Phytophthora ramorum across a range of tested species, and that penetration and damage into timber wood is largely superficial.
· Demarcated areas in Scotland and Wales will also be lifted, reflecting cross-border research and a coordinated GB-wide approach to plant health policy.
· Forest Research is Great Britain’s principal organisation for forestry and tree-related research. The extensive programme of research to investigate the pathogen in GB was led by Forest Research pathologists specialising in Phytophthora diseases.