session 5: with the benefit of hindsight: a bioeconomic analysis of past pest incursions

biosecurity built on science

Project: 1033 With the benefit of hindsight:

a bioeconomic analysis of past pest incursions

Assoc. Prof. Ben White UWA, Cheryl Day UWA

Plant Biosecurity Cooperative Research Centre


Hindsight: Understanding of a situation or event only after it has happened or developed

With the benefit of hindsight


With the benefit of hindsight

GrowthSpreadJumpDamage

NaturalPassiveActivePrecautionary

InterstateInternationalProducer welfareConsumer welfare

AdaptationTransactionLossesTrade


Incursion data and spread models Define:

- a policy set- rules about how information determines actions

Estimate costs and benefits

Steps in developing a bioeconomic model


𝑡1𝐼𝑛𝑐 𝑡1𝐷𝑒𝑡 , 𝑁𝑆𝑡 2𝐷𝑒𝑡 ,𝑃 𝑆0

Dam

age

cost

per

uni

t tim

e

Popu

latio

n (x

it)

Time

xPS

xNS

𝑡 2𝐷𝑒𝑡 ,𝑁𝑆𝑡 2𝐼𝑛𝑐

Incursion property 2

Incursion property 1

triggers eradication

Precautionary surveillance detects pest earlier than natural detection

Jump

and precautionary surveillance

Natural detection

NS - Natural surveillance

PS - Precautionary surveillance

Surveillance, detection and eradication


WA Khapra beetle (Trogoderma granarium) Victoria Potato cyst nematode (Globodera rostochiensis)

Surrounding metropolitan properties

How the model is applied to the case studies


Containment $Eradication $

Do nothing

Optimal policy set


Natural surveillance $0

Maximum surveillance$611/visit

1.0

Larger soil sampling grid

Smaller soil sampling grid

Khapra beetle trap density and frequency of checking

Potato cyst nematode density of samplingNatural surveillance $0

Maximum surveillance$118/ha

1.0

Surveillance intensity – transaction costs


Precautionary eradication – eradication without detection

Precautionary surveillance

up to 500 m

Surveillance and eradication cut-off distances


Wider industry costs


PCN results – Optimal policyPolicy

Average cost ($m)

No farmsInfested

(505 max)

No control 121.5 294

1 km + 2 km 17.8 78

10 km + 2 km 14.6 70

20 km + 2 km 18.0 79

0

50

100

150

200

Status

No.

of p

rope

rties

InfestedLinked

Present value at 3%, annual time step over 30 years 1991-2021,50 replicates for each policy


Khapra beetle results – Optimal policyPolicy Average cost

($m)Non-eradication

after 2 yrs

Wrap + spray eradication 11.2 5%

Wrap + spray eradication 5 weeks delay 83.9 32%

Spray only 14.3 9%

Policy variable Optimal

Eradication Wrap + spray

Eradication cut-off House only

Surveillance intensity 0.74

Surveillance cut-off 70 m (10 houses)

Surveillance stand down 0.82

Present value at 5%, weekly time step over 2 years, 500 replicates for each policy


Better decisions for regulators and industry- Sally Troy, emphasized the importance of estimating and

comparing risks – our methods do just that- John van Schagen DAFWA End-user Advocate

Future - Citrus canker, grape phylloxera and wheat

streak mosaic virus- Economic assessment template to provide

a set of economic rules

Beneficiaries, delivery and users


Information - Preparedness for incursions Costs of delay are significant Risk management - Analyse outcomes as probability

distributions Importance of passive surveillance linked to education Incentives for producers to be vigilant and report incursions

quickly, even if it costs them.

Conclusions


For more information, please email [email protected]

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session 5: with the benefit of hindsight: a bioeconomic analysis of past pest incursions

Science