Presented by:

Simone Tuten on behalf of the Department of Agriculture, Western Australia Plant Biosecurity Team.

International Plant Health Risk Analysis Workshop Niagara Falls, October 2005

A new semi-quantitative model to determine pest A new semi-quantitative model to determine pest introduction frequencyintroduction frequency

Please note:

The research reported here is in progress and is not finalised. The study results have not been subjected to scientific peer review and are presented purely as a demonstration of the authors’ current thinking. This presentation reflects the authors’ opinions and does not necessarily reflect the opinions of the Department of Agriculture, Western Australia. Additionally this research has been undertaken by the Western Australian State Department of Agriculture and not by National Government Departments. Any reliance on the information presented here is entirely at your own risk and the Department of Agriculture, Western Australia takes no responsibility whatsoever for the results of your doing so.

BackgroundBackground

Western Australia

BackgroundBackground

• Deserts

BackgroundBackground

• Deserts

• Limited road access

BackgroundBackground

• Deserts

• Limited road access

• check points

• 20

points

BackgroundBackground

• Deserts

• Limited road access

• check points

• Ports

BackgroundBackground

• Pest and disease freedoms

• Codling moth (Cydia pomonella )

• Oriental fruit moth (Grapholita molesta)

• Apple scab (Venturia inaequali)

Background – Australia’s quarantine Background – Australia’s quarantine systemsystem

Quarantine continuum

• Partnership

• States/Territories

• Interstate trade

• National

• International trade

Background – Australia’s quarantine Background – Australia’s quarantine systemsystem

Memorandum of Understanding

• Agreement

• Enables SPS compliance

• Consistency

Background – WA Plant BiosecurityBackground – WA Plant Biosecurity

• State pest risk analyses

• Market access

• National pest risk analyses

Background – WA Plant BiosecurityBackground – WA Plant Biosecurity

Important considerations

• integration of consequences and PEES

• impact of volume

• multiple pathways

The Model - FeaturesThe Model - Features

• Enhances existing methodology

• Incorporates

• variable input data

• trade volume

• complex scenarios

• multiple pathways

• Pest initiated is best

The Model - PathwayThe Model - Pathway

Simplistic schematic

Pest Present in Source Orchard

Yes = Imp1

No = 1 - Imp1

Harvested Fruit Infected

Yes = Imp2

No = 1 – Imp2

Pest Survives Pack House

Yes = Imp3

No = 1 – Imp3

Pest Survives Transport

Yes = Imp4

No = 1 – Imp4

Pest Survives Quarantine Clearance No = 1 – Imp5

Yes = Imp5

Importation of Pest

P1 Proportion of Fruit Purchased by Retailers

P2 Proportion Purchased by Consumers from Retailers

P3 Proportion of Fruit Discarded as Waste

P4 Pest Viability

Viable Waste from Consumers

Exp1 -

Exposure of Commercial Hosts

PPDc Partial Probability of Distribution to Commercial Hosts

Partial Probability of Establishment

Partial Probability of Establishment

Partial Probability of Establishment

PPDh Partial Probability of Distribution to Household Hosts

PPDw Partial Probability of Distribution to Wild Hosts

Exp2 -

Exposure of Household Hosts

Exp3 -

Exposure of Wild Hosts

ImportationDistribution

The Model – OutputThe Model – Output

Years before 1st introduction = 1+RiskGeomet(PEEannual)

1+RiskGeomet(PEEannual)

Introduction frequency = 1/PEEannual

The Model – OutputThe Model – Output

1/PEEannual

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 10 100 1000 10000 100000 1000000 10000000 100000000 1E+09

Volume of trade (units)

An

nu

al r

isk

(

PE

E an

nu

al =

1-(

1-P

EE u

nit)v

olu

me)

High (0.58)

Moderate (0.5)

Low (0.175)

Very low (0.0255)

Extremely low(0.0005005)Negligible (0.0000005)

Unit Risk

Volume and riskVolume and risk

• Non linear

• high unit risk rapid increase at low volumes

• low unit risk rapid increase occurs later

• Consider all pathways and total volume

• Monitor phytosanitary measures efficacy

Volume and riskVolume and risk

Introduction frequency - applicationsIntroduction frequency - applications

Risk Communication

• Tangible

ALOP

• Defining

Consequences

• integrating consequences with PEES

• how often is too often?

Introduction frequency - applicationsIntroduction frequency - applications

Management strategies

• phytosanitary measures efficacy

Non-SPS application

• development of policy

• business planning

• strategy planning to minimise impact of trade

Where to from here?Where to from here?

Validation

• Check model assumptions

• using data collected during 2 seasons

• review and release model

Risk assessment

• Link between introduction frequency and

• consequences

• ALOP

The plant biosecurity team

Director Plant Biosecurity – Dr Shashi Sharma ssharma@agric.wa.gov.au

Activity Specialist/Policy – Mr Mark Stuart mstuart@agric.wa.gov.au

Pathologist/modelling – Ms Nichole Burges nburges@agric.wa.gov.au

Pathologist – Dr Satendra Kumar skumar@agric.wa.gov.au

Entomology/climate modelling – Mr Marc Poole mpoole@agric.wa.gov.au

Entomology – Dr John Botha jbotha@agric.wa.gov.au

Biometrics – Ms Jane Speijers jspeijers@agric.wa.gov.au

Policy – Ms Simone Tuten stuten@agric.wa.gov.au