Phytophthora pluvialis is a fungus-like pathogen known to affect a variety of trees including western hemlock, tanoak, pine (Pinus radiata, Pinus patula and Pinus strobus) and Douglas fir. It was originally reported in Oregon, USA in 2013 on tanoak and Douglas fir and was subsequently identified as the pathogen responsible for ‘red needle cast’ of radiata pine in New Zealand.
Phytophthora pluvialis was discovered in a woodland in Cornwall in September 2021, where it was found to be affecting mature western hemlock and Douglas fir trees. This was the first finding of the pathogen in Europe, and precautionary measures were introduced placing movement restrictions on affected areas.
Trade restrictions on conifer trees were subsequently lifted across seven English counties on Wednesday 4 March 2026, after a review concluded that Phytophthora pluvialis no longer met the criteria for quarantine pest status.
Demarcated areas in Cornwall and Devon, Cumbria, Herefordshire, Surrey, Gloucestershire and Shropshire have therefore been revoked, together with the demarcated areas in Scotland and Wales, re-enabling the unrestricted movement of affected conifer species for the forestry and plant trade sector.
The decision to lift restrictions was informed by 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 has concluded that Phytophthora pluvialis poses a low environmental and economic risk.
Further general information about Phytophthora pluvialis is available on GOV.UK.