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Risk-based management of plant disease

last modified Mar 28, 2017 02:50 PM

A new study in New Phytologist from Nik Cunniffe's group shows how disease management strategies based on epidemiological risk can lead to successful control of plant disease invasions. A number of plant diseases are currently the subject of high-profile attempted management. Examples include Xylella fastidiosa on olives in Italy, and Phytophthora ramorum in forests in the UK and USA. Disease control most often turns on removing all hosts within a certain radius of detected infection. The underpinning idea is that such a strategy can outpace the wave of asymptomatic cryptic infection surrounding symptomatic hosts. However, by always controlling using the same fixed radius, these strategies are potentially inefficient, since they take no account of the effect of the level of disease or local host density on the potential for future spread.

The paper focuses on more sophisticated control strategies based on the idea of epidemiological risk. These strategies remove host plants that are expected to cause to a large number of infections, accounting for the chance of a host being asymptomatically infected as well as the number of infections it would then cause. The paper uses the relatively recent attempt to eradicate citrus canker from Florida (1996-2006) as a case study to show how risk-based disease management can be effective. It also shows how complex control strategies can be translated into simpler variable radius strategies, which would be sufficiently transparent to be acceptable to affected stakeholders.

The first author on the paper was Sam Hyatt Twynam, who did the initial work as part of his prize-winning Part III Physics project, and has subsequently gone on to work in sports betting (via a cameo role on BBC's Saturday night show Britain's Brightest). Richard Stutt and Chris Gilligan were also involved in the study, as was Stephen Parnell (at Salford University) and Tim Gottwald (at USDA in Florida).

Hyatt-Twynam, S. R., Parnell, S., Stutt, R. O. J. H., Gottwald, T. R., Gilligan, C. A. and Cunniffe, N. J. (2017), Risk-based management of invading plant disease. New Phytol. doi:10.1111/nph.14488