Asian soybean rust is a fungal disease of leguminous plants that was introduced into the southeastern United States late last year, presumably during the hurricane season (USDA 2004), It is fast-acting and highly contagious, and has plagued agriculture in such countries as Thailand, Taiwan, Japan, and India for years; recently it has spread to Argentina and Brazil (Dorrance, et al. 2005). The damage caused by this disease is defoliation, which can reduce crop yields by up to 80 percent (Stokstad 2004) Soybean rust may be caused by several species of fungi, but the most tenacious, Phakopsora pachyrizi, is now posing a threat to U.S. crops. The dispersal rate of the fungal spores is especially high in windy and rainy weather, and the survivability ofthe pathogen is increased by numerous over wintering hosts, including the ubiquitous southern weed, kudzu. No commercial variety of soybean has shown resistance to the pathogen as of yet, and scientists believe that it may take as long as five years forpathogen-resistant genes to be expressed in modern cultivars (Stokstad 2004 and Ozkan 2005).
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