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Oral: Risk Assessment


Spatio-temporal analysis of rice blast incidence in China
F. Guo (1), M. Lu (2), B. Wu (1), F. Guo (1) (1) China Agricultural University, China; (2) National Agro-tech Extension and Service Center, China

Rice blast caused by Magnaporthe oryzae is a devastating disease worldwide. Knowledge on the spatial and temporal patterns of disease risk at regional scale is important to understand its epidemic. In this study, rice blast incidence was surveyed in the main rice production areas in China between June 10 and September 10 from 2009 to 2014. Rice blast often had two peaks each year, and was highest in 2012 among these years. For the major production areas other than north eastern China, the disease incidence was highest in the Yunnan-Guizhou plateau, followed by Sichuan Basin and southern China, and lowest in central and eastern China. Spatial autocorrelation analysis revealed a significant correlation at distances ranging from 110KM to 340KM. Results of iso cluster unsupervised classification conducted in GIS on interpolated incidence on different dates could classify rice production areas into low and high disease risk regions. Although the regions with high disease risk varied among years, some regions frequently had high disease risk, such as areas along the border of Yunnan and Guangxi, the border of Sichuan and Chongqing, the border of Fujian and Guangdong, and the junction of Jiangxi, Anhui, and Zhejiang. The results of hot spot analysis were consistent with those of cluster analysis. The spatial and temporal patterns of rice blast obtained from this study provided a reference to efficiently organize resources for better management of the disease in China.