Pivonia S, Yang X B
Iowa State University, Department of Plant Pathology, Ames 50011.
Plant Dis. 2004 May;88(5):523-529. doi: 10.1094/PDIS.2004.88.5.523.
Soybean rust (Phakopsora pachyrhizi Sydow) has been known to occur in eastern Asia and Aus-tralia for decades. In recent years, the disease entered Africa and South America and has spread rapidly in these continents. It has become a concern to the U.S. soybean industry. To assess the threat of soybean rust, we used a modeling approach to determine the potential geographical zones where the fungus might overwinter and serve as source areas for seasonal epidemics. Long-term meteorological averages were used to assess the temperature stresses by using CLIMEX, and the dry stress with an algorithm developed in this study. Integration of stresses was used to predict the likelihood of survival of the rust in a defined location. Our results suggest that the new soybean rust invasions in Africa and South America occurred in the areas where the fungus might persist year-round. The main regions where rust has not been reported but might overwinter are located in the western hemisphere, including northern South America, Central America, the Caribbean, Mexico, southern Texas, and Florida. Southeastern China and neighboring areas are suggested as the primary regions where initial spores for soybean rust epidemics in central China are produced. If the disease is to establish in the United States, it is likely to be restricted to parts of Florida and southern Texas during the winter in the frost-free areas or areas where the fungus could overcome short periods of below-freezing temperatures. Occurrence of rust epidemics within the U.S. soybean belt would depend on south-to-north dispersal of uredospores.
大豆锈病（Phakopsora pachyrhizi Sydow）在东亚和澳大利亚已存在数十年。近年来，这种病害传入非洲和南美洲，并在这些大陆迅速蔓延。它已成为美国大豆产业的一大担忧。为评估大豆锈病的威胁，我们采用建模方法来确定该真菌可能越冬并成为季节性流行病菌源地的潜在地理区域。利用CLIMEX，通过长期气象平均值评估温度胁迫，并运用本研究开发的一种算法评估干旱胁迫。综合胁迫因素来预测锈菌在特定地点存活的可能性。我们的结果表明，非洲和南美洲新出现的大豆锈病入侵发生在真菌可能终年存活的地区。尚未报告但可能越冬的主要区域位于西半球，包括南美洲北部、中美洲、加勒比地区、墨西哥、得克萨斯州南部和佛罗里达州。中国东南部及周边地区被认为是中国中部大豆锈病流行初期孢子的主要产生区域。如果这种病害在美国定殖，冬季可能仅限于佛罗里达州部分地区和得克萨斯州南部无霜区或真菌能够耐受短期低于冰点温度的地区。美国大豆种植带内锈病流行的发生将取决于夏孢子从南向北的传播。
