What we are doing about tree pests and diseases
We are fighting back against pests and diseases. Find out what we're doing to prevent the spread and protect the UK’s trees.Learn more
A fungal disease that attacks cedars and hemlock, Sirococcus tsugae can cause disfigurement and eventually death to shoots and branches.
Credit: Barnaby Wylder / Forestry Commission
Credit: Sam Milner / Forestry Commission
Credit: Ana Perez Sierra / Forest Research
Common name: none
Scientific name: Sirococcus tsugae
What does it affect?: Atlas cedar, deodar cedar, cedar of Lebanon, western hemlock, eastern hemlock, mountain hemlock
Areas affected so far: across the UK
Origin: not known
Sirococcus tsugae is a fungal disease that causes shoot death and cankers on cedar and shoot death on hemlock. Scientists are still investigating the lifecycle of this fungus.
S. tsugae has been known in the US since 1966. In Europe, it was first reported in the UK and Germany in 2014. It is now found in a number of different locations across the UK.
We don’t know how the first introductions happened. It most likely arrived via imported infected trees or possibly via infected imported seeds or cut foliage.
Biosecurity is very important with this type of pathogen. The disease is spread by spores from the needles and bark of the infected tree. Rain and wind spread the spores and they can also be transported on clothing, footwear and vehicle tyres.
To combat pests and diseases like Sirococcus tsugae we have: