Woodland managers, landowners, the forest industry and tree nurseries are being urged to remain vigilant after the Forestry Commission (FC) and Forest Research (FR) identified the tree pathogen Phytophthora pluvialis in a woodland in Cornwall.

The UK chief plant health officer has confirmed the finding, following routine Forestry Commission plant health surveillance activities.

Phytophthora pluvialis, is a fungus-like pathogen known to affect a variety of tree species, including western hemlock, Douglas fir, tanoak and several pine species (in particular radiata pine).

It is reported to cause needle cast (where needles turn brown and fall off), shoot dieback and lesions on the stem, branches and roots.

This is the first report of this pathogen in Europe. At this stage, it is unknown if Phytophthora pluvialis is the direct cause of the observed symptoms which have been found on mature western hemlock and Douglas-fir trees.

Further surveillance

Forestry Commission, Forest Research and the Animal and Plant Health Agency are rapidly conducting further surveillance and diagnostic analysis to understand more about the pathogen and ensure that any required control measures are swiftly undertaken to stop its spread.

Nicola Spence, the UK chief plant health officer said:

“We are taking swift and robust action against this finding of Phytophthora pluvialis, as part of our well-established biosecurity protocol used for tree pests and diseases.

I urge all sectors to support efforts to tackle this pathogen by checking the health of western hemlock and Douglas-fir trees. Key symptoms to look for are lesions on the stem, branch or roots.

“Any sightings should be reported to the Forestry Commission via its Tree Alert online portal.”

To protect the country against this pathogen, the Forestry Commission has introduced a demarcated area in Cornwall, to restrict the movement of materials capable of spreading the disease.