Current threats
If you report any sightings of the below threats then please report these through TreeAlert.
More information about current and past threats is available on the Forest Research website.
Phytophthora pluvialis
Phytophthora pluvialis is present in the UK and internationally.
Known hosts: wide range of conifer species.
Ash dieback (Hymenoscyphus fraxineus)
Ash dieback is present throughout Scotland.
Known hosts: ash species.
Conifer root and butt rot (Heterobasidion annosum)
Present throughout Scotland.
Known hosts: wide range of conifer species.
Dothistroma needle blight (Dothistroma septosporum)
Dothistroma needle blight is present throughout Scotland.
Known hosts: pine species including Corsican pine, lodgepole pine and Scots pine. Can also infect other conifer species.
Great spruce bark beetle (Dendroctonus micans)
Great spruce bark beetle is present in southern Scotland.
Known hosts: spruce species and very occasionally pine.
Large pine weevil (Hylobius abietis)
Present throughout Scotland.
Known hosts: young conifers including pine and spruce species and young broadleaves.
Oak processionary moth (Thaumetopoea processionea)
A small number of recent introductions on large trees for landscaping are currently thought to have been eradicated in Scotland (monitoring continues).
Known hosts: oak trees.
Phytophthora disease of alder (Phytophthora alni)
A small number of recent introductions on large trees for landscaping are currently thought to have been eradicated in Scotland (monitoring continues).
Known hosts: oak trees.
Phytophthora austrocedri
Present throughout Scotland, particularly uplands.
Known hosts: juniper and cypress species.
Pine tree lappet moth (Dendrolimus pini)
Pine tree lappet moth is present in a limited area in the Beauly catchment.
Known hosts: several conifer species, but mainly Scots pine.
Ramorum disease on larch (Phytophthora ramorum)
Ramorum disease is present in Scotland. Most problematic in the wetter, western regions.
Known hosts: larch species are the most susceptible. Can also infect other conifer and broadleaf species.
Future Threats
Asian longhorn beetle (Anoplophora glabripennis)
Ramorum disease is present in Scotland. Most problematic in the wetter, western regions.
Not now known to be present in the UK (an outbreak in Kent in 2012 was eradicated).
Known hosts: wide range of broadleaf tree species.
Bronze birch borer (Agrilus anxius)
Not known to be present in the UK.
Known hosts: all species of birch.
Citrus longhorn beetle (Anoplophora chinensis)
Not known to be present in the UK.
Known hosts: wide range of broadleaf tree and shrub species.
Elm zigzag sawfly (Aproceros leucopoda)
Present in the UK. Not known to be present in Scotland.
Known hosts: several species of elm tree.
Emerald ash borer (Agrilus planipennis)
Not known to be present in the UK.
Known hosts: several species of ash tree.
Larger eight-toothed European spruce bark beetle (Ips typographus)
Known to be present (and breeding) in a 2018/19 outbreak in Kent and east Sussex, this now being subject to statutory eradication action. Not known to be present in Scotland.
Known hosts: most species of spruce tree and some other conifers.
Pine wood nematode (Bursaphelenchus xylophilus)
Not known to be present in the UK.
Known hosts: most conifers, especially pine species including Scots pine.
Pitch canker of pine (Fusarium circinatum)
Not known to be present in the UK.
Known hosts: pine trees and Douglas fir.
Siberian silk moth (Dendrolimus sibiricus)
Not known to be present in the UK.
Known hosts: wide range of conifer tree species.
Xylella (Xylella fastidiosa)
Not known to be present in the UK.
Known hosts: very wide range of plants including several species of broadleaf tree.