Phytophthora ramorum and

Phytophthora kernoviae

05/04/20112

Phytophthora ramorum

Causes sudden oak death in USA

First found in Britain in 2002

In Britain until 2009 found on ornamental shrubs in nurseries, gardens, parks in England

Since 2007 found in western Scotland on ornamental shrubs

Rhododendron is a major host – spore production and spread

05/04/20113

Pr on beech

Until 2009:On trees Pr causes bleeding stem cankers as well as leaf and shoot infections

05/04/20114

Bleeding lesions on beech

Inoculum from rhododendrons

Pr

spread to

beech

05/04/20115

Pr

on larch in England

In 2009

Pr reported on Japanese larch in SW England

First finding of infections on Japanese larch

Pr now confirmed on JL at ~70 sites in southern England

Impact on other conifer spp. growing locally (WH, DF, GF)

Removal of larch from FC plantations in West Country

Infected maturing larch commonly 20-25m tall

Young larch (5-8 yr) probably infected from the mature larch

05/04/20117

Multiple stem cankers on larch

05/04/20118

Pr produces spores on foliage –

important source of inoculum

allowing aerial spread of the disease –

felling of infected trees essential

Pr foliar symptoms on larch

05/04/20119

Spores on larch needles

05/04/201110

Pr distribution on larch in UK

In 2010

Pr found on Japanese larch in Wales, Northern Ireland and one site in Scotland

Surveys and river baiting in SW Scotland currently

Regenerating hemlock (4-10yr) amongst young larch

Dieback and resinosis

05/04/201112

Stem symptoms on 5-7 y Douglas fir

05/04/201113

Compare sporulation on JL with R. ponticum, Vaccinium, sweet chestnut, bay laurel –

sporangia and chlamydospores

produced

Compare bark susceptibility of JL, hybrid larch and EL

Persistence of P. ramorum on infected sites

Better/faster diagnostic methods, to assess the presence of the pathogen in samples, logs, residues

Ongoing and future research

05/04/201114

Phytophthora kernoviae

Discovered in woodlands in Cornwall in 2003

Known only in Britain and New Zealand, origin unknown

Infects Rhododendron and other shrubs and can cause lethal stem cankers on beech

In 2008 found in the west of Scotland (mild, moist climatic conditions)

05/04/201115

SW England P. kernoviae site

05/04/201116

Phytophthora kernoviae

In 2008-09

found infecting Vaccinium in Cornwall and on Arran

Causes necrotic lesions, stem dieback and death of above-ground parts

05/04/201117

Pk

infection of Vaccinium

Suitability of the UK climate for Phytophthora ramorum and P. kernoviae

05/04/201119

P. ramorum and

P. kernoviae

• Status report for Scotland available on FC website

• Pr is a quarantine pest and presence on infected shrubs/trees must be reported, Pk

treated as

such in Britain

• Regular inspections and surveys of nurseries/gardens/woodland

• Infected trees must be felled, foliage destroyed and surrounding area surveyed

• Biosecurity

measures in place at infected sites