Reassessing the threat posed by pine wood nematode to UK forestry

Project leads  Dr Sarah Facey | Forest Research; Talor Whitham | PhD Student, Forest Research and University of Reading

Lead organisation  Forest Research
Project status  Active (Duration 3 years)
Project funding  £210,000
Research outcome  Response
Context

Pine wilt disease (PWD) is a lethal wilting disease recognised as one of the most serious threats to conifer forestry worldwide. The disease is caused by the pine wood nematode (PWN) (Bursaphelenchus xylophilus), which travels between trees on the bodies of Cerambycidae monochamus beetles. PWN enter trees through beetle feeding wounds and egg notches, grow inside the trees and gather on developing beetles inside the wood, before the beetle emerges and travels to feed and mate, spreading the nematode further.

PWN has been intercepted on infested packaging material coming through UK ports and processors and could arrive in the UK. The UK has no indigenous Monochamus species, however, PWN is known to have formed new associations with native Monochamus beetles in countries outside of its native North American range. Other beetles in the UK display similar life history behaviours to Monochamus beetles and there is concern that they could act as alternative vectors for PWN. This is a horizon scanning PhD project that seeks to inform future forestry about the risks posed if PWN arrives in the UK.

Research aims and objectives
Aim

The project examines the relationship between Monochamus and PWN and assess the risk of UK longhorn and bark beetles as potential vectors of PWN.

Objectives:
  • Survey UK pine wood samples and associated beetles to assess the native nematode species present in the environment currently.
  • Characterise and compare the volatile organic cuticular compounds (VOCCs) to those found in Monochamus.
  • Perform experiments exposing PWN to a range of UK beetle cuticular extractions, both with and without the co-presence of Monochamus extractions to assess nematode responses to chemical cues.
  • Draw up actionable recommendations for PWN.
Expected outcomes
  • Peer reviewed journal articles.
  • Recommendations for policies regarding PWN in the UK.
Further resources linked to this project
News: CFP PhD Student wins first prize at a conference (Published: 15 December 2023)

News article: CFP PhD Student wins first prize at a conference

Talor Witham, PhD student with the Centre for Forest Protection at Forest Research and Reading University presented at a specialist conference in Nanjing.

Intern Diary: Josh - 2024/25 (Published: 14 May 2025)

Blog: Intern diary – Josh the nematode nerd

Josh spent his six month internship with the Centre for Forest Protection learning all about identifying nematodes. He worked with PhD student Talor in the Holt Lab containment facility at Forest Research and became quite an expert in identifying the different parts of these microscopic worms.

Microscope image of a nematode worm

Pine wood nematode (PWN) under a microscope.

Glossary & Key Terms
Cerambycidae monochamus beetle

A genus of longhorn beetles within the family Cerambycidae, known for their role as vectors of the pine wood nematode (Bursaphelenchus xylophilus), the causal agent of pine wilt disease (PWD). It is not known to be present in the UK.

Conifer (Pinophyta)

Cone-bearing and usually evergreen trees. They are a distinct group of trees that are economically significant due to their ability to grow quickly even on poor soils and in harsh climates. These trees yield timber that is highly suitable for industrial use, which has led to their widespread planting and management across many countries. Examples of conifer trees found in the UK include Scots pine, Douglas fir, and Norway spruce.

Cuticular extractions

The process of removing the cuticle, or outer layer, of a plant or insect, or the extraction of cuticular waxes from these cuticles.

Horizon scanning

The systematic process of identifying and asessing potential threats from non-native tree pests and diseases before they become significant problems.

Pine (Pinus)

Evergreen conifer trees belonging to the genus Pinus, identified by their needle‑shaped leaves and woody cones, and are widely grown in British forests for timber and ecological value. For more information, see Pine - Forest Research.

Pine wilt disease (PWD)

A serious disease of pine trees caused by the pine wood nematode (Bursaphelenchus xylophilus), a microscopic worm that blocks the tree’s water‑conducting tissues, causing rapid wilting, needle browning and usually death of the tree. It is not known to be present in the UK. For more information, see Pine wood nematode (Bursaphelenchus xylophilus) - Forest Research.

Pine wood nematode (Bursaphelenchus xylophilus)

A microscopic, worm‑like organism that infects pine and other conifer trees, causing a deadly disease known as pine wilt, which disrupts water movement in the tree and often leads to rapid tree death. It is not known to be present in the UK. For more information, see Pine wood nematode (Bursaphelenchus xylophilus) - Forest Research.

Vector

An organism that transmits a pathogen, disease, or parasite from one animal or plant to another.

Volatile Organic Cuticular Compounds (VOCCs)

Carbon-based chemicals produced by living organisms, that evaporate into the air at room temperature.

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