Xu, Xiang-Ming,
Ridout, Martin S.
(2001)
*
Effects of prevailing wind direction on spatial statistics of plant disease epidemics.
*
Journal of Phytopathology,
149
(3-4).
pp. 155-166.
ISSN 0931-1785.
(doi:10.1046/j.1439-0434.2001.00591.x)
(The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)
(KAR id:9371)

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Official URL http://dx.doi.org/10.1046/j.1439-0434.2001.00591.x |

## Abstract

A stochastic simulation model was used to study the effects of the strength of prevailing wind (W), the size/shape (Q) of sampling quadrats and their orientation in relation to the prevailing wind direction (D) on spatial statistics describing plant diseases. Spore dispersal followed a half-Cauchy distribution with median distance ?, which depended on simulated wind speed. The relationship of spatial autocorrelation at distance k (?k) to disease incidence (p) and distance was well described by a four-parameter (?, ?1, ?2, ?3) power-law model; at a given p, ?k declined exponentially with distance. A total of 35 different quadrat sizes, ranging from 4 to 432 plants, were used to sample the simulated epidemics for estimating intraclass correlation (?). The ?-values decreased exponentially with increasing quadrat size; a binary power law model with three parameters (?1, ?4, ?5) successfully related ? to p. In general, the effect of W and D was greatest on the parameters ?, ?1, ?2 and ?3. The effect of W on ?, ?1, ?2 and ?3 depended critically on the spatial pattern of initial infected plants (Y); W had greatest effect for the random pattern. In contrast, the main effect of D and its interaction with W on the parameters ?, ?1, ?2 and ?3 were large and consistent over different initial conditions. Variations in ?1, ?4 and ?5 were predominantly due to Y and Q. Only for ?5 under the clumped pattern was the effect of W very large. For the parameters ?1, ?4 and ?5 there was a large interaction among W, Q and D for the clumped and regular patterns. As expected, in general, the effect of D increased with increasing prevailing wind strength, quadrat size and quadrat length : width ratio. Using square quadrats reduced significantly the effect of W on the parameters ?1, ?4 and ?5; however, the effect of W on ?5 was still very large for the clumped pattern. Sampling perpendicular to the prevailing wind direction generally resulted in larger differences in the nine estimated parameters.

Item Type: | Article |
---|---|

DOI/Identification number: | 10.1046/j.1439-0434.2001.00591.x |

Subjects: | Q Science > QK Botany |

Divisions: | Divisions > Division of Computing, Engineering and Mathematical Sciences > School of Mathematics, Statistics and Actuarial Science |

Depositing User: | Martin Ridout |

Date Deposited: | 11 Oct 2008 22:18 UTC |

Last Modified: | 16 Feb 2021 12:20 UTC |

Resource URI: | https://kar.kent.ac.uk/id/eprint/9371 (The current URI for this page, for reference purposes) |

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