Phytophthora austrocedri

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Phytophthora austrocedrae is a pathogen with potential to cause significant biodiversity damage (Photo: M Elliot/WTML)

Phytophthora austrocedri is a damaging plant pathogen that was first seen in the UK in 2011.

What is Phytophthora austrocedri?

Phytophthora austrocedri is particularly worrying because it affects juniper, one of our most rare native trees. There are only around 400 hectares of juniper woodland in Britain, mostly in Scotland. It supports a specialised group of insects, fungi and lichens, as well as birds such as goldcrest, and provides winter cover for black grouse. The disease often causes death of the host tree.

Symptoms

  • Dieback of foliage, stem and collar lesions
  • Foliage appears lighter colour than that of healthy trees, but later withers and turns bronze, then brown
  • Can be confused with symptoms of other infections

Causes

  • Fungus like pathogen Phytophthora austrocedri thought to be present in Argentina and Chile for at least 50 years

Outlook

  • Confirmed in juniper at the Upper Teesdale National Nature Reserve (the largest area of native juniper woodland in England) in the North Pennines in 2011, and in Lawson cypress and Nootka cypress trees at two sites in Scotland
  • Found at over 100 juniper sites, most in Scotland but also a number in Cumbria, and Devon by 2015
  • Likely to spread slowly by natural means but has also been found in plant nursery stock

Report it

If you think you’ve spotted this disease please inform the Forestry Commission using the Tree Alert reporting tool. Three good-quality digital photographs are required to aid identification.

For more information visit the Forestry Commission.

Trees face huge challenges

With more new pests and diseases reaching our shores tackling pests and diseases is now an urgent priority

Learn about the threats