phytophthora ramorum and phytophthora kernoviae · causes sudden oak death in usa. ... origin...
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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