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Abstract Detail



Host/Plant Pathogen Interactions and Plant Health Management

Carisse, Odile [1], McRoberts, Neil [2].

Long term dynamics of Botrytis leaf blight ofonion under management in Quebec.

Data from 19 years of lesion count records for Botrytis leaf blight of onion (Botrytis squamosa) in Quebec province were used to examine the long-term dynamics of the disease. Non-linear time series analysis was used to infer the lag dependence and polynomial degree of non-linearity in the dynamics of epidemics of the disease occurring in the upper and lower canopies of onion crops. These analyses indicated that the lag dependency in leaf blight epidemics was three seasons, but there was no strong evidence for non-linearity in the dependence; the model with highest coefficient of prediction included only first-order polynomial functions of the lagged annual epidemic intensities. Over the time span of the data set there was evidence that increasing sophistication in disease monitoring and targeting of control actions has reduced the amplitudes of oscillations in epidemic intensity around the mean value, while the linear rate of decrease in the mean was 5% per annum. When a stochastic function derived from weather data,, and representing the seasonal probability of Botrytis infection, was used to explain the residual variability from the deterministic time series model, the resulting stochastic model produced dynamics consistent with the observed data. Allowing for the relatively short time series of the data, the analyses are consistent with the hypothesis that the dynamics of Botrytis population in the main onion production in Quebec are regulated around an equilibrium value but subject to inter-seasonal stochasticity, and that management of the disease has increased the level of regulation in the series.


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1 - Agriculture and AgriFood Canada, 430 Gouin Bvl, St-Jean-Richelieu, Qc, J3B 3E6, Canada
2 - University of California, Davis, , Plant Pathology Department,, One Shields Ave.,, Davis, , CA, 95616,, USA

Keywords:
long-term
Disease management
plant diseases.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PPA024
Abstract ID:548
Candidate for Awards:None


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