Emerging Pests and Diseases – A Global Crisis ?

Sarah GreenForest ResearchNorthern Research Station

30/11/20112

Introduction

Global examples of emerging pests and diseases

Six new emerging tree pathogens in Britain since 2000

Phytophthora lateralis as an example of emerging pathogen

Plant trade an important pathway, so what can/should be done ?

30/11/20113

Examples from around the globe……

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Chestnut blight

introduced into North America from China/Japan

An estimated 4 billion American chestnut trees killed since 1910

30/11/20115

Dutch elm disease (Ophiostoma novo-ulmi)

From eastern Asia

Devastated elms in Europe and North America since 1960s

Introduced to UK on elm logs imported from Canada

Spread globally through timber trade

30/11/20116

Phytophthora ramorum on tanoak in California (late 1990s)

Affecting hundreds of kms

of coastal forest in California –

killing 100% of all tanoaks in some areas

Introduced from an unknown location through the nursery trade

30/11/20117

Emerald Ash Borer (Agrilus planipennis)

Native to Asia

Introduced to North America in 2002

Solid wood cargo packaging implicated as pathway

Spread through eastern USA and Canada –killed over 20 million ash trees since 2002

30/11/20118

Ceratocystis platani on Platanus spp. in Europe

Introduced from North America on wood products during WWII

Recent increased spread amongst European countries via nursery trade

30/11/20119

Pitch pine canker (Fusariumcircinatum)

in Spain since late 2000’s

Origin probably Central America

Impact on Pinus radiata in N. Spain but European pine spp. at risk

Spread internationally via transport of contaminated seed and seedlings

30/11/201110

Pine wood nematode(Bursaphelenchus xylophilus)in Portugal since 1999

Native to N. America

Spread to Asia and Europe through trade in woodProducts

46 million m3

pine lost in Japan due to disease

Pine wilt disease now spread across whole of Portugal

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Puccinia psidii on Myrtaceaeincluding Eucalyptus

Native to South and Central America

Spread to Florida then Hawaii

Spreading in Australia since April 2010 -

over 100 potential

hosts to infect in Australia

Trade in live plants implicated in disease spread

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The current situation in Britain……

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Phytophthora austrocedraeon Lawson cypress and Nootka cypress

From ?

Associated with widespread decline of Austrocedrus chilensis in Patagonia(mal del cipres)

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Phytophthora lateralis on Lawson cypress

From SE Asia

Devastated Lawson cypress in Oregon/California since 1950s

Impact in Britain on amenity plantings

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Phytophthora ramorumon larch

Host jump !. Which host next ?

From Eastern Asia via Europe ?

Removal of larch from all FC plantations in SWEngland

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Phytophthora kernoviaeon vaccinium

From Asia via New Zealand ?

Potential impact on native heathland

vegetation

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Dothistroma Needle Blighton pines

From where ?

384 subcompartments

of SPpositive for DNB in 2011

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Pseudomonas syringae pv. aesculi on horse chestnut

From India

In 2007 survey (FR) symptoms on:70% of trees in England36% of trees in Wales42% of trees in Scotland

Further spread in Europe

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Phytophthora lateralis is a fine example of what happens when a pathogen leaves home……

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Phytophthora lateralis

Main host is Lawson cypress – mainly root pathogen

First appeared in Pacific North West of USA in 1920s –

now major

pathogen of Lawson cypress across native range

Recently isolated from old-growth Chamaecyparis forests in Taiwan

Does not cause any significant damage in Taiwan

Has co-evolved with its host

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Global occurrence of P. lateralis

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P. Lateralis outbreaks in UK

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‘UK variant’

found at Balloch

and Kilmaronock-

genetically and phenotypically

unique

‘Oregon variant’

found in Oregon, France, NI, Scotland and England

‘Taiwan variant’

found in Taiwan

Balloch

TGTTTTACATTCATGGGCTATTCCCTCATTAGGTATTAAATTAGATGCTTGTCCAGGACGKilmaronock

TGTTTTACATTCATGGGCTATTCCCTCATTAGGTATTAAATTAGATGCTTGTCCAGGACG Greenock

TGTTTTACATTCATGGGCTATTCCCTCATTAGGTATTAAATTAGATGCTTGTCCTGGACG RoukenGlen

TGTTTTACATTCATGGGCTATTCCCTCATTAGGTATTAAATTAGATGCTTGTCCTGGACG Oregon

TGTTTTACATTCATGGGCTATTCCCTCATTAGGTATTAAATTAGATGCTTGTCCTGGACG France

TGTTTTACATTCATGGGCTATTCCCTCATTAGGTATTAAATTAGATGCTTGTCCTGGACG Taiwan

TGTTTTACATTCATGGGCTATTCCATCATTAGGTATTAAATTAGATGCTTGTCCTGGACG

P. Lateralis : three

‘variants’

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How did P. lateralis get here ?

Two nursery interceptions in 2011 on:

Thuja occidentalisLawson cypress

Plants imported from France and The Netherlands

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How did P. lateralis get here ?

Two P. lateralis outbreaks adjacentto garden centres

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Global trade in plant material

Strong evidence to link treepest and disease outbreaks to global trade in plant material

Increased number of tree pest/pathogen interceptions in the UKFera/FC data

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Montesclaros

Declaration !

“As scientists studying diseases of forest trees, we recognize that the international trade of plant material is increasing the risks to

forest health

worldwide. The evidence for this view is based on the recent, unprecedented rise in numbers of alien pathogens and pests emerging in natural

and planted

forest ecosystems in all parts of the globe. We thus propose a phasing out of

all trade in plants and plant products determined to be of high risk

to forested

ecosystems but low overall economic benefit.”