Containment and Eradication of Phytophthora kernoviae

in the UK

Karen PughDefra

Plant Health & Seeds Inspectorate

Phytophthora kernoviaeDiary of main events

October 2003• New, unknown Phytophthora isolated from Rhododendron and Fagus (beech tree) at two separate sites in

Cornwall, south west of EnglandDecember 2003• CSL begins testing all PHSI samples for the new Phytophthora as well as for Phytophthora ramorumMarch 2004• Working name of Phytophthora taxon C (PtC) used for organismJune 2004• First finding on MagnoliaJuly 2004• P. kernoviae found on Rhododendron at three sites in South Wales• First findings on Gevuina avellana (Chilean hazelnut), Liriodendron tulipifera (tulip tree) and Michelia sp.August 2004• Two woods with very high levels of infection in Rhododendron understorey and several infected Fagus trees

found in Cornwall - further surveys later revealed a cluster of outbreaks in the Redruth area of Cornwall • First finding on Quercus ilexSeptember 2004• First finding on Pieris• First finding on a nursery in CheshireOctober 2004• Phytophthora kernoviae proposed as the name of the organismDecember 2004• Legislation introduced establishing a Pk management zone in Redruth area of Cornwall to contain disease2005/2006• Ongoing surveys found new outbreaks in woodlands and gardens in west Cornwall and south Wales

Phytophthora kernoviaeoutbreaks

33 Outbreaks• 26 in Cornwall (1 nursery finding)• 1 in Devon• 5 in South Wales (4 Swansea; 1 Cardiff)• 1 in Cheshire (nursery finding)

Climatic Comparison betweenthe Oregon SOD Location and

the UK 5 km 1961-2000 long term averageusing CLIMEX

CLIMEX Match Index35 - 5050.001 - 5555.001 - 6060.001 - 6565.001 - 7070.001 - 7575.001 - 80

Phytophthora ramorum findings#S

Host range of P. kernoviae: 5 plant familiesTrees

Ornamentals

Ericaceae:PierisRhododendron* Magnoliaceae:

LiriodendronMagnolia (8 spp.)*Michelia*

Fagaceae:Fagus (50 trees)*Quercus ilex*Q. robur*Common to Pr and Pk

Proteaceae - GevuinaWinteraceae - Drimys

Foliar disease symptoms

Foliage blight

Shoot tip dieback symptoms

petiole necrosis

Foliar disease symptoms

Leaf spot or blotch

Bleeding canker symptoms

Inner bark necrosis

P. kernoviae – Disease Management Zone

• Objective: to eradicate disease over an agreed period and to contain the disease whilst eradication is in progress

• Measures will take account of local needs

• Zone consists of– an area to which control

measures apply– a surrounding host free strip

which is monitored• Zone defined accurately and

shown clearly on a map

P. kernoviae – Disease Management Zone

Containment measures• Controls on movement of susceptible

plants/plant parts– Woodland and gardens – prohibition – Commercial nurseries

• Movement only under official control• Regular programme of inspection and testing• Consignment freedom• Removal of plant debris from all pots

P. kernoviae – Disease Management Zone Proposals

Containment measures• Biosecurity measures

– Woodland • Public notices• Advise/prohibit access (people and dogs)• Advise cleaning footwear

– Public gardens/nurseries• Hygiene protocol for staff• Close/re-route paths; re-surface paths; regular removal

of plant debris• Cordon-sanitaire around premises

P. kernoviae – Disease Management Zone Proposals

Containment measures• Host-free strip

– Boundary of Zone to consist of an area free from susceptible hosts

– Make use of arable/grass fields or roads– Boundary to be monitored closely

What Does The Future Hold?

Clearance of high risk sites

Monitor outbreak sites & disease development

Maintain management zone & continue survey work

Carry out further research

Trap plants as indicators of pathogen activity in the field

….this green and pleasant land