Predicting the Benefits of Banana Bunchy Top Virus Exclusion from Commercial Plantations in Australia David Cook Department of Agriculture and Food Western Australia biosecurity built on science Cooperative Research Centre for National Plant Biosecurity
biosecurity built on science
biosecurity built on science
Outline Banana Bunchy Top Virus (BBTV) □ The issue □ Impact and management of the virus Estimating the benefits of an exclusion policy □ Model in brief □ Results Conclusions
biosecurity built on science
The Issue Regional economic significance □ Australia contributes less than 0.5% of global production; □ In 2010, Qld., NSW, NT and WA produced 301,450T of bananas with a gross value of $492.2 million. BBTV is one of the most economically significant diseases of bananas □ Present in eastern Australia since the early 1900s; □ In 1993, a five-year Banana Plant Health Improvement Project was initiated by the industry aimed at eradicating BBTV from Australia; □ Substantial reductions in BBTV prevalence in commercial plantations was achieved, but not eradication due to externalities and incentive misalignment; □ Currently an exclusion management approach is being considered. biosecurity built on science
BBTV Management Established throughout Southeast Asia, the Philippines, Taiwan, most of the south Pacific Islands, and parts of India, Africa and Australia (NSW and Qld.); The destructive effects of the virus were demonstrated in NSW in the 1920s when approximately 90% of the area under banana cropping was forced out of production. The banana aphid (Pentalonia nigronervosa), established in most banana growing regions throughout the world, transmits BBTV; Control within plantations involves insecticide treatments (2 × dimethoate applications, approx. $150/ha); Since there are no known treatments against BBTV once infection has occurred, exclusion from commercial plantations involves destruction of affected plants and creation of a buffer zone (i.e. “cookie cutter” approach, approx. $15,000/ha); biosecurity built on science
Conceptual Model p
h(q) g(q)
p1
BBBTV = ΔPS - c(s,a)
p0
f(q) q1
q0
q biosecurity built on science
Impact Simulation Model Psat = µA
Pent
New satellite population
Pest Parameters:
Established population
A = 4 Dπrt
2
N=
K
Pent - Entry probability Pest - Establishment probability Parameters: A - Area infected DetectionDprobability = Binomial(1.0, - Diffusion coefficient 0.6) r - Intrinsic rate of population Probability of eradication an infected & densitygiven increase -0.15×A area, A = e N - Local population density Nmin - Initial population density K - Carrying capacity Psat - Satellite probability µ - Rate of new satellite − rt generation t - Time period biosecurity built on science
− 1e 1 + K N min
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041
Area Affected by BBTV (Ha)
BBTV Spread
12,000
10,000
8,000
Nil Management
6,000 95%
75%
Mean
4,000 25%
5%
2,000
Active Containment
0
Year
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Benefits of Exclusion
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Conclusions Biosecurity risk management decisions are highly uncertain □ Any model is a simplification of reality. There appear to be substantial production benefits from adopting an active containment policy for BBTV □ $16-27 million per year. The other component of CUBA – the spatial incursion management tool □ Recently showcased in a war games workshop in Melbourne using the example fire blight; □ A model demonstration will be held at morning tea and lunch time. Thank you to all CUBA project team members, past and present! □ Jean-Philippe Aurambout, Art Diggle, Jacqueline Edwards, Michael Hurley, Darren Kriticos, Shuang Liu, Kim Lowell, Abu-Baker Siddique and Oscar Villalta. biosecurity built on science
Thank You
LONG LIVE CUBA!! Dr David Cook
Senior Economist South West Agricultural Region Department of Agriculture and Food Western Australia PO Box 1231 BUNBURY WA 6231 T: +61 8 9780 6179 M: +61 477 302245 E: david.cook@agric.wa.gov.au W: www.agric.wa.gov.au/
biosecurity built on science