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The Sensitivity of the Epidemic Growth Rate to Weather Variables, with an Application to Yellow Rust on Wheat

February 2007 , Volume 97 , Number  2
Pages  202 - 210

Konstantina Papastamati and Frank van den Bosch

Biomathematics and Bioinformatics Division, Rothamsted Research, Harpenden, Herts. AL5 2JQ, UK

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Accepted for publication 13 July 2006.

We first show how to estimate the exponential epidemic growth rate, r, for different combinations of three weather variables. Then we derive a method to quantify the sensitivity of r to a weather variable as a function of the pathogen life cycle variables of latent period, basic reproductive number, and the mean and standard deviation of the sporulation curve. The method can be used to identify the most important weather variable and pathogen life cycle component in terms of epidemic progress. The method is applied to yellow rust, caused by Puccinia striiformis, on winter wheat. We conclude that the most important weather variable for the progress of yellow rust is temperature, followed by dew period and light quantity. By far, the most important pathogen life cycle component is the basic reproductive number, especially at low and high temperatures. This disagrees with the general view that latent period is the most important variable at low temperatures. We discuss explanations of this.

Additional keywords: exponential growth rate, sensitivity analysis.

© 2007 The American Phytopathological Society