Improving the use of pheromone traps to monitor oak processionary moth

This project aims to improve the effectiveness of commercially available pheromone traps for monitoring populations of oak processionary moth (OPM), and to integrate their use within the wider management programme for this important forest pest.

Research objectives

Specific research objectives are to:

  • determine the optimum placement of traps within the tree canopy
  • compare the efficiency of different types of traps and pheromone lures (sex attractant) obtained from different sources
  • determine the influence of other factors, such as habitat, tree density and weather conditions, on numbers of moths caught
  • establish relationships between the numbers of moths caught in pheromone traps and OPM population densities in the surrounding area.

Results so far

Field trials have shown that the type of trap (Delta or funnel), the pheromone lure and the position of the trap in the tree can all affect the numbers of OPM caught in pheromone traps, and therefore influence the quality of monitoring. Significantly more male moths were captured in traps placed in the upper canopy of oak trees (77%) compared with the mid-canopy (19%) or lower canopy (5%). Funnel traps also caught six times more male OPM than Delta traps, and chemical analysis revealed considerable differences between three commercially available pheromone lures.


This project started in 2010 and is ongoing.

Related Resources

How to identify Oak Processionary Moth

Native species that can be mistaken for Oak Processionary Moth

Other oak defoliators

Forestry Commission webpages on OPM 

Pest Risk Analysis of Oak Processionary Moth


Williams DT, Straw N, Townsend M, Wilkinson AS and Mullins A. (2013). Monitoring oak processionary moth Thaumetopoea processionea L. using pheromone traps: the influence of pheromone lure source, trap design and height above the ground on capture rates. Agricultural and Forest Entomology 15, pp126—134. 

Straw, N., Williams, D. & Tilbury, C. (2013) Monitoring the Oak Processionary Moth with Pheromone Traps. Forestry Commission Practice Note 20. Forestry Commission, Edinburgh.


Dr David Williams

Funders and partners

This research is currently funded by the Forestry Commission under the Programme Advice and Scientific Support for Tree Health

Early trials work was also part funded by Defra

Forestry Commission policy
This research underpins the evidence base for the delivery of healthy and resilient forests and wider ecosystems which is part of the Tree Health and Plant Biosecurity Action Plan

Current action against OPM