Phytophthora ramorum in a Larch tree

Last week we posted a piece on the Fingle Woods blog about an outbreak of the virus like disease Phytothphora ramorum which affects a variety of trees including larch – see here. We have now had a second outbreak confirmed in Halls Cleave Wood which is part of Fingle Woods. The Forestry Commission’s Plant Health scientists were out this week to sample another Japanese larch they had identified from a aerial survey. I visited the area yesterday to see it for myself.

P ramorum 4
This is Halls Cleave Wood from the bottom track – all the conifers in this picture are Japanese larch

P ramorum 2
This is the infected tree which has now been felled. You can see the characteristic sap bleed which is the tree’s response – infections start at the top of the tree and work down

P ramorum 1
Here is a close up of the sap bleed – it is very characteristic

P ramorum 3This is the surrounding area – all the larch trees will have to be removed with 100 metres of the infected tree. This work will start very soon. Fortunately the stand does contain a good understory of bilberry and various native broadleaves so we are hoping that the remedial works won’t be too damaging – indeed they could be seen as part of the woodland restoration.

P. ramorum is very infectious and is spread by aerial spores so we will have to keep a close eye over the coming months and years on adjacent stands of larch and act accordingly. Rather worryingly P. ramorum can also infect bilberry – that is why we are acting very quickly. P. ramorum is a notifiable disease and we will soon receive a notice from the Forestry Commission instructing us to remove the surrounding trees.

P. ramorum is endemic now in the south west and elsewhere in the UK and is having a devastating impact on conifers and other species particularly ornamental shrubs such as Rhododendrons in formal gardens.

For more information on this tree disease see the dedicated Forestry Commission web site – here.


You can also watch this video which details the symptoms – if you find what you think is an infected tree contact the Forestry Commission

3 thoughts on “Phytophthora ramorum in a Larch tree

  1. Pingback: Forestry Advisors come to Fingle Woods | A Dartmoor blog

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