International Plant Health Risk Analysis Workshop Niagara Falls, Canada, 24 - 28 October 2005
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Page 1 International Plant Health Risk Analysis Workshop Niagara Falls, Canada, 24 - 28 October 2005 David Cook A Stochastic Bioeconomic Model to Demonstrate the Benefits of Pest Exclusion The Case of the Varroa Bee Mite
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A Stochastic Bioeconomic Model to Demonstrate the Benefits of Pest Exclusion The Case of the Varroa Bee Mite. International Plant Health Risk Analysis Workshop Niagara Falls, Canada, 24 - 28 October 2005 David Cook. Outline. Introduction - Cost sharing arrangements for invasive species - PowerPoint PPT Presentation
Transcript of International Plant Health Risk Analysis Workshop Niagara Falls, Canada, 24 - 28 October 2005
Page 1
International Plant Health Risk Analysis WorkshopNiagara Falls, Canada, 24 - 28 October 2005
David Cook
A Stochastic Bioeconomic Model to Demonstrate the Benefits of Pest Exclusion
The Case of the Varroa Bee Mite
Page 2
• Introduction
- Cost sharing arrangements for invasive species
- The role of economics in risk assessment
- The Varroa Bee Mite
• The model
- Framework
- Assumptions
- Outputs & Interpretation
• Results
- Implications for cost sharing arrangements
• Conclusions
Outline
Page 3
Biosecurity Service Provision in Australia
• Two “emergency response” cost sharing agreements:
– Emergency Animal Disease Response Agreement (EADRA)
– Emergency Plant Pest Response Deed (EPPRD)
• Cost share categories, public vs. private benefit of eradication:
Public Private
Category 1 100% 0%
Category 2 80% 20%
Category 3 50% 50%
Category 3 20% 80%Varroa
(EADRA)
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Varroa Mite
S. Bauer, ARS/USDA D. Anderson, CSIRO Entomology
• V. destructor is a parasitic mite that attacks adult honeybees and their developing larvae;
• Infestations result in the production of deformed bees, reduced longevity of individuals and slow death of the colony;
• Present throughout much of the world, but has yet to be detected in Australia;
• Spread between colonies usually high;
• Can be controlled in the beekeeping industry (at considerable cost), but wild European honeybees are severely affected.
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Previous Estimates
• Industries Assistance Commission (1985)
– <A$160 million
• Gill (1989), Gibbs and Muirhead (1998)
– Between A$0.6 billion and $1.2 billion
• Gordon and Davis (2003)
– A$1.7 billion
• Robinson et al (1989) - US$9.3 billion
Morse and Calderone (2000) - US$14.6 billion
Muth and Thurman (1995) - US$600 million.
• Pollination benefits ≠ expected Varroa damage.
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Parameters:
Parr - Arrival probability
Pest - Establishment probability
D - Diffusion coefficient
r - Intrinsic rate of density increase
K - Carrying capacity
N - Local population density
µ - Rate of new satellite generation
Amax - Total host area
Amin - Initial area affected
g - Rate of spread
Total area summed across all satellites increases until reaching Amax, at which point it remains constant
The Model
gte
.1A
A1
AA
min
max
max
New satellite population
Established population
NATIONAL BOUNDARY
rteNK
KN
11
min
APsat
estPentP
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Interpretation
• Framework provides a base-case entry scenario where spread and impact are severe
• In the event of a ‘real’ incursion, results represent the benefits of eradication over time
i.e. one half on a benefit cost analysis
• The model says nothing of efficiency in managing risk over time.
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Cost & Revenue Implications
• 25 crops used in the analysis
• Crops used were placed in one of four categories roughly proportional to pollinator reliance
– Low (0-5% yield loss)– Moderate (0-10%)– High (0-20%)– Very High (10-30%)
• Number of additional commercial hives required varied between 0 and 5 per hectare, depending on the crop
• Additional costs per hive estimated between A$90-120/yr.
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Expected Economic Impact (A$/Yr) – 30 Year Average
= $36,657,900
X <= $51,382,30095.0%
X <= $21,933,5005.0%
0 10 20 30 40 50 60 70
Values in $ Millions
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Cost/time Relationship Over 30 Years
5%
Mean
95%
0
10
20
30
40
50
60
0 10 20 30
Year
Ave
rag
e A
nn
ual
Exp
ecte
d B
enef
its
fro
m
V
. d
estr
uct
or
Exc
lusi
on
($'
000,
000)
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Pollination Benefits by Industry
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
Es
tim
ate
d A
ve
rag
e P
olli
na
tio
n B
en
efi
t A
ttri
bu
tab
le t
o E
xc
lus
ion
($
'00
0/y
r)
Alm
ond
Blueberry
Sunflow
er
Pum
pkin
Cherry
Cucum
ber
Apple
Plum
Apricot
Nectarine
Peach
Field P
ea
Macadam
ia Nut
Pear (N
ot Nashi)
Straw
berry
Mandarin
Orange
Mangoes
Lemon &
Lime
Canola
Lupin
Avocado
Waterm
elon
Rockm
elon
Zucchini
Plant Industry
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Sensitivity Analysis
• Probability of entry
– Prevention better than cure?
• Intrinsic rate of population growth
– Implies high returns to investment in R&D activities concerning the control of inter-colony spread
• Yield Loss
• Discount rate
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Conclusions
• Estimate that annual benefits of exclusion to Australian plant industries of between A$21.9 million and A$51.4 million;
• Results far less than previous estimates, but are nonetheless indicative of an extremely destructive pest;
• Cost sharing arrangements in Australia relating to the eradication of Varroa may be inappropriate.
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Contact CSIRO
Phone 1300 363 400
+61 3 9545 2176
Email [email protected]
Web www.csiro.au
Thank You
ContactName David Cook
Title Research Economist
Phone +61 2 6246 4093
Email [email protected]
Web www.csiro.au
