Long-Distance Spore Transport of Wheat Stripe Rust Pathogen from Sichuan, Yunnan, and Guizhou in Southwestern China.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is the most devastating wheat disease in China. Although pathogens oversummering and overwintering in many regions of southwestern China have been studied, spore exchange among these regions is largely unknown. It is especially important to study the role of Sichuan, Yunnan, and Guizhou provinces in southwestern China in contributing to regional disease outbreaks in the major wheat-growing areas of China. Long-distance transport of P. striiformis f. sp. tritici urediniospores after oversummering and overwintering in Sichuan, Yunnan, and Guizhou was investigated using the HYSPLIT-4 model based on meteorological data. Results suggest that the pathogen spores can interchange frequently among Sichuan, Yunnan, and Guizhou in both spring and autumn. The sources of inoculum in Sichuan, Yunnan, and Guizhou have a high probability of impacting the epidemics in northern, northwestern, and southwestern China. In particular, disease epidemics in Guizhou can be affected not only by local inoculum but also by that from Yunnan in the spring.