Boning Li, State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China;
Xueren Cao, State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, and Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture, Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571001, China;
Lin Chen, Ningxia Entry-Exit Inspection and Quarantine Bureau, Yinchuan 750002, China;
Yilin Zhou and
Xiayu Duan, State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences;
Yong Luo, Department of Plant Pathology, China Agricultural University, Beijing 100193;
Bruce D. L. Fitt, University of Hertfordshire, Hatfield, Hertfordshire AL10 9AB, UK;
Xiangming Xu, Horticulture Research International, East Matting, West Matting, Kent ME19 6BJ, UK;
Yuli Song, Institute of Plant Protection, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China;
Baotong Wang, College of Plant Protection, Northwest Agriculture and Forestry University, Yangling 712100, China; and
Shiqin Cao, Institute of Plant Protection, Gansu Academy of Agricultural Sciences, Lanzhou 730070, China
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Accepted for publication 10 February 2013.
Blumeria graminis f. sp. tritici, the pathogen that causes wheat powdery mildew, can oversummer as mycelia or conidia on leaves of volunteer wheat plants in cool mountainous areas in China. In this study, the regions in China where B. graminis f. sp. tritici can oversummer were identified on the basis of the probability that temperature remains below a critical temperature that is lethal to B. graminis f. sp. tritici. Two methods, one describing the relationship between the average temperature (20 to 26°C) in a given continuous 10-day period and wheat powdery mildew severity, the other describing the relationship between the average temperature (26 to 33°C) and the number of lethal days on powdery mildew development, were used to calculate the oversummering probability using weather data for 743 sites across China. Spatial interpolation based on the ordinary kriging method was conducted for the regions without observation. Oversummering probability values were similar for most locations estimated between the two methods. The B. graminis f. sp. tritici oversummering regions in China were identified to be in mountainous or high-elevation areas, including most regions of Yunnan, west and central areas of Guizhou, south and northwest Sichuan, south and east Gansu, south Ningxia, north and west Shaanxi, central-north Shanxi, west Henan and Hubei, and some regions in Qinghai, Tibet, and Xinjiang. When the oversummering sites from this study were compared with observed survey data for some of these sites, about 90% of sites where B. graminis f. sp. tritici oversummering was observed had been found suitable by both methods. The coincidence frequency and the area under the receiver operating characteristic curve for model 2 were higher, albeit only slightly, than those for model 1. Thus, both methods may be used to assist in disease management and further investigation on pathogen oversummering.
© 2013 The American Phytopathological Society