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Science Exchange 2015 | Conference Handbook 89
With the benefit of hindsight: a bioeconomic analysis of past pest incursions (1033)Dr m. Chalak1,2, Assoc Prof B. White1,2 and Miss C. Day1,2 1Plant Biosecurity Cooperative Research Centre, 2University of Western Australia
The potato cyst nematode (PCN) (Globodera rostochiensis) is a serious pest of potatoes that causes significant crop damage in Australia and worldwide. PCN was discovered in Wandin Victoria in 1991 and then spread slowly to other regions in the state up to the present day. The aim of this study is to analyse the costs and benefits of past policy and management decisions in response to the incursion of PCN in Victoria. To do this we first estimate the probability of spread for different control strategies using information about the location and the date of spread of PCN in Victoria as well as the location of PCN-free potato farms. We use Monte Carlo simulation to compare the Net
Present Value for the cost of different decisions. Our analysis shows that the lowest economic costs are achieved if PCN is eradicated from the state and PCN infested farms were converted to other enterprises. This decision minimises the soil movement and spread of PCN. However, the decision by the Victorian Government was to contain PCN within infestation zones and allow potato production to continue at PCN infested farms. Containment has relatively higher economic costs because it results in a higher spread rate for PCN and has larger containment and transaction costs due to requirements for surveillance and movement licences.
Presenting authors biography
Morteza Chalak is a Research Assistant Professor at the University of Western Australia, School of Agricultural and Resource Economics. His research interests include bioeconomic analysis of biosecurity issues, economic modelling and optimisation for the control of pest and disease in Australia. He has been working at the University of Western Australia since 2009. In 2009 he graduated from his PhD from Wageningen University, the Netherlands. The title of his PhD
thesis was Economics of controlling invasive species.
Dr Morteza Chalak 08 6488 5508 [email protected]
Assoc Prof Ben White Project leader 08 6488 3409 [email protected]
More information
www.pbcrc.com.au/research/project/1033
biosecurity built on science
With the benefit of hindsight: a bioeconomic analysis of past pest
incursions
Morteza ChalakResearch Assistant Professor
Plant Biosecurity Cooperative Research Centre
biosecurity built on science
Problem being addressed
Potato Cyst Nematode (PCN) (Globodera rostochiensis) is a serious pest of potatoes that has caused significant crop damage in Australia and worldwide
biosecurity built on science
Problem being addressed
Low levels of infestation are difficult to detect PCN can survive in soil in the absence of a host plant for 20-30
years
biosecurity built on science
Problem being addressed
PCN can be dispersed through movement of soil by human The maximum loss of potato production has ranged from 60%
to 97%
biosecurity built on science
Problem being addressed
PCN was found in Victoria in 1991
biosecurity built on science
Problem being addressed
Potato industry in Victoria Fresh potato: 99,584 tons Potato processing: 137,135 tons Seed production: 39,919 tons
biosecurity built on science
Problem being addressed
Policies optionsPolicy 1: Current (containment while allowing potato production on infested farms)
Policy 2: Containment and not allowing potato production on infested farms
Policy 3: Early eradication attempt
Policy 4: No control and not allowing potato production on infested farms
Policy 5: No control and allowing potato production on PCN infested farms
biosecurity built on science
Problem being addressed
Institutional costs
Fumigation costs
Market restrictions
Surveillances Yield loss
Containment costs
Early Eradication
No control
biosecurity built on science
Problem being addressed
Question: is the current policy cost-effective compared to alternative policies?
Containment
PCN
biosecurity built on science
Spread of PCN
PCN was discovered in Victoria in 1991 in Wandin and then spread slowly to other regions in the state up to the present day.
biosecurity built on science
Spread of PCN
We estimate the location of potato farms using Australian Bureau of Statistics (2011), Basemaps aerial photos, soil and slope maps.
biosecurity built on science
Spread of PCNProbability of spread
PS: probability that an uninfested potato farm is infested by an infested farm
d: the distance of the uninfested potato farm from the infested farm
a: spread coefficient
+
=i
ii da
dPC 1
+=
dad
PS 1
biosecurity built on science
Spread of PCN
a (spread coefficient)Mean
2.376
Average for 1.046 and 2.376
1.7065
Minimum value for 95% confidence interval
1.046
Maximum value for 95% confidence interval
5.556
Maximum value for 99% confidence interval
6.24
Mean
2.376
Average for 1.046 and 2.376
1.7065
Minimum value for 95% confidence interval
1.046
Maximum value for 95% confidence interval
5.556
Maximum value for 99% confidence interval
6.24
biosecurity built on science
Spread of PCN
a (spread coefficient assumptions)Mean
Policy: Current (containment while allowing potato production)
2.376
Average for 1.046 and 2.376
Policy: Containment and not allowing potato production on infested farms
1.7065
Minimum value for 95% confidence interval
Policy: Early eradication attempt
1.046
Maximum value for 95% confidence interval
Policy: No control and not allowing potato production on infested farms
5.556
Maximum value for 99% confidence interval
Policy: No control and allowing potato production on infested farms
6.24
biosecurity built on science
Spread of PCN
0
10
20
30
40
50
60
0 10 20 30
num
ber
of in
fest
ed f
arm
s
Years
6.24
5.556
2.376
1.7065
1.046
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 10 20 30
New
infe
stat
ions
Years
6.24
5.556
2.376
1.7065
1.046
biosecurity built on science
Model We use the earliest infestation (Wandin in 1991) as the
initial condition and simulated the spread of PCN for different policy scenarios for 24 years (T, 1991 to 2015).
Monte Carlo simulation using 1000 random draws from a binomial distribution.
+
=i
ii da
dPC 1
biosecurity built on science
Results Policy cost
Policy 1: Current (containment while allowing potato production)
Benefit loss per farm= $137,000, a=2.376, NPV loss for all farms=$2.9m
Containment cost=$4.7m. SD: 1,075,373.
$7.6m
Policy 2: Containment and no potato production on infested farm
Benefit loss per farm= $194,000, a=1.076, NPV loss for all farms=$3.9m
Containment cost=$4.7m. SD: 1,260,438.
$8.6m
Policy 3: Early eradication attempt
Benefit loss per farm= $194,000, a=1.046, NPV loss for all farms=$3.7m
Eradication cost=$0.8m. SD: 882,583.
$4.5m
Policy 4: No control and no potato production on infested farms
Benefit loss per farm= $194,000, a=5.556, NPV loss for all farms=$5.7m
Control cost=0. SD: 5,737,055.
$5.7m
Policy 5: No control and allowing potato production on PCN infested farms
Benefit loss per farm= $132,000, a=6.24, NPV loss for all farms=$4.6m
Control cost=0. SD: 5,880,363.
$4.6m
biosecurity built on science
Results
0
200
400
600
800
1000
7.2
8.1
8.7
9.9
10.8
11.1
12.3
15.4
Mor
e13
.215
.1
Num
ber o
f sim
ulat
ions
Present value of economic costs ($million
0
200
400
600
800
1000
4.3
6.6
7.3
6.4
7.5
5.9
8.2
8.9
10.8
10.1
11.0
Num
ber o
f sim
ulat
ions
Present value of economic costs ($million)
0
200
400
600
2.4
7.4
15.7
17.3
22.3
30.7
37.3
35.6
50.6
44.0
49.0
Num
ber o
f sim
ulat
ions
Present value of economic costs ($million)
Containment
No control
Early eradication attempt
biosecurity built on science
Who will directly benefit from the research?
Government organisations including Departments of Environment and Primary Industries
Potato growers
biosecurity built on science
Challenges and issues arising from the research
General challenges dealing with new incursions: Availability of recorded data to estimate spread model. Short time frames for quick policy responses.
biosecurity built on science
Impact delivery plan
State departments of agricultureare advised to consider a rapid eradication response if PCN is detected in new regions.
biosecurity built on science
The End-User Advocates perspective
The director of Plant Biosecurity for the Department of Agriculture and Food, John van Schagen. General support with the project Interest in the results found Applicability of the results with the new incursion of similar
pests
biosecurity built on science
Thank you
For more information, please email [email protected]
Thanks to Ben White (UWA), Michael Renton (UWA), Cheryl Day (UWA), Maggie Triska (UWA), Sarah Collins (DAFWA), Jacque Edwards (DEDJTR, Victoria), John Van Shagen (DAFWA), Jacquie Edwards (DEPI Victoria), Mike Hodda (CSIRO), David Cook (DAFWA).
mailto:[email protected]
With the benefit of hindsight: a bioeconomic analysis of past pest incursionsProblem being addressedProblem being addressedProblem being addressedProblem being addressedProblem being addressedProblem being addressedProblem being addressedProblem being addressedSpread of PCNSpread of PCNSpread of PCNSpread of PCNSpread of PCNSpread of PCNModelResultsResultsWho will directly benefit from the research?Challenges and issues arising from the researchImpact delivery planThe End-User Advocates perspectiveThank you