title: Risk-based management of invading plant disease.
abstract: Effective control of plant disease remains a key challenge. Eradication attempts often involve removal of host plants within a certain radius of detection, targeting asymptomatic infection. Here we develop and test potentially more effective, epidemiologically motivated, control strategies, using a mathematical model previously fitted to the spread of citrus canker in Florida. We test risk-based control, which preferentially removes hosts expected to cause a high number of infections in the remaining host population. Removals then depend on past patterns of pathogen spread and host removal, which might be nontransparent to affected stakeholders. This motivates a variable radius strategy, which approximates risk-based control via removal radii that vary by location, but which are fixed in advance of any epidemic. Risk-based control outperforms variable radius control, which in turn outperforms constant radius removal. This result is robust to changes in disease spread parameters and initial patterns of susceptible host plants. However, efficiency degrades if epidemiological parameters are incorrectly characterised. Risk-based control including additional epidemiology can be used to improve disease management, but it requires good prior knowledge for optimal performance. This focuses attention on gaining maximal information from past epidemics, on understanding model transferability between locations and on adaptive management strategies that change over time.
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
authors.forename: Samuel R
authors.initials: SR
authors.lastname: Hyatt-Twynam
authors.affiliation: School of Environment and Life Sciences, University of Salford, Manchester, M5 4WT, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Parnell
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
authors.forename: Richard O J H
authors.initials: RO
authors.lastname: Stutt
authors.affiliation: USDA Agricultural Research Service, 2001 South Rock Road, Fort Pierce, FL, 34945, USA.
authors.forename: Tim R
authors.initials: TR
authors.lastname: Gottwald
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Gilligan
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
authors.forename: Nik J
authors.initials: NJ
authors.lastname: Cunniffe
mesh_terms: D058865:Introduced Species; D008954:Models, Biological; D010935:Plant Diseases / Q000517:prevention & control* / Q000706:statistics & numerical data; D018570:Risk Assessment
keywords: adaptive control; citrus canker; disease management; eradication; risk-based control; stakeholders; stochastic epidemic model