"On November 9, 2004, Asian soybean rust (ASR) was discovered in the United States in an experimental field in Louisiana. In the following three weeks, it was discovered in eight additional southern states -- Alabama, Arkansas, Florida, Georgia, Mississippi, Missouri, South Carolina, and Tennessee. Because ASR's arrival in the United States came late in the crop year, it is not thought to have had any measurable effect on 2004 soybean production. Furthermore, its detection has provided an early warning and has given the U.S. soybean sector time to prepare strategies to guard against possible ASR damage to the 2005 soybean crop. ASR is a harmful fungal disease that affects the growth of several commercial plants, most notably soybeans. The rust spores, once windborne, can spread rapidly and have been known to infect an entire region the same year the disease is first detected. ASR has reduced soybean yields by 10% to 80% in infected areas. The disease's rapid transmission rate coupled with an abundance of host species suggests that eradication would be unlikely once the fungus is established in the United States. As a result, the most effective treatment is thought to be the development and use of resistant plant varieties. However, no commercial U.S. soybean cultivar is resistant to or tolerant of ASR. In the short term, the only effective responses are costly fungicides and the use of early-maturing soybean cultivars."
CRS Report for Congress, RL32225
National Agricultural Law Center: http://www.nationalaglawcenter.org/crs/