This follow-on project builds on the work of PHC2022/07 (Understanding an emerging health threat to Caledonian Scots pine) and seeks to understand the emergence and impact of Curreya pithyophila, a previously rare fungal pathogen now affecting Scots pine (Pinus sylvestris) across Scotland. The disease appears to involve an unusual interaction between two fungal spore types (phragmospore and dictyospore forms of C. pithyophila) and the native adelgid Pineus pini, with subsequent colonisation by the canker-causing Crumenulopsis sororia. Preliminary investigations have shown the problem is widespread, yet its drivers remain unclear.

The project aims to: (1) determine the genetic structure and possible introduction pathways of the fungal types; (2) compare UK specimens with international herbarium records to establish origin; (3) assess disease presence and severity in Caledonian pine populations at key sites; (4) evaluate resistance across different pine provenances; and (5) test whether the fungus can infect Scots pine without P. pini through inoculation trials.

Expected outcomes include a clearer understanding of the pathogen’s origin and spread, identification of susceptible pine populations, and improved risk assessments for Caledonian pine. Outputs will include genomic data, scientific publications, stakeholder webinars, and practical management recommendations. This research will inform conservation strategies for one of Scotland’s most iconic native tree species.

Image of Curreya pithyophila colonising Scots Pine by Sarah Green from Forest Research © Crown Copyright