Soybean rust is a disease that affects soybeans and other legumes. It is caused by two types of fungi, Phakopsora pachyrhizi, commonly known as Asian soybean rust, and Phakopsora meibomiae, commonly known as New World soybean rust. P. meibomiae is the weaker pathogen of the two and generally does not cause widespread problems. The disease has been reported across Asia, Australia, Africa, South America and the United States. Importance Soybean is one of the most important commercial crops around the world and in the United States. Asian soybean rust is the major disease that affects soybeans. It causes lesions on the leaves of soybean plants and eventually kills the plants. The disease has caused serious yield loss of soybeans. In the areas where this disease is common, the yield losses can be up to 80%. The first reported cases in the United States occurred in 2004. This population originated in northern South America or the Caribbean. The spores were most likely spread by Hurricane Ivan. In 2002, USDA reported 10-60% yield losses in South America and Africa. in countries were this pathogen is established, estimated losses are between 10 to 80% depending on the inoculation and environmental conditions. Host and symptoms Soybean rust is caused by two types of fungi, Phakopsora pachyrhizi and Phakopsora meibomiae. It affects several important commercial plants, however, most notable for soybeans. Asian Soybean Rust can infect and reproduce on 90 known plant species, 20 of which are found in the United States, such as, soybeans, dry beans, kidney beans, peas. asian soybean rust also infects yellow sweet lover, vetch, medic, lupine, green and kidney bean, and lima and butter bean.leguminous forage crops such as trefoil and sweet clover and weeds such as kudzu. At the early stage of Asian Soybean Rust, it causes yellow mosaic discoloration on the upper surfaces of older foliage. At this stage, it is usually hard to identify since the symptoms are relatively small and poorly defined. Later as the disease continues to progress, the leaves will turn yellow and there will be lesions mostly on the undersides of the leaves and sometimes on petioles, stems or pods and premature defoliation can also be observed. In Phakopsora pachyrhizi will begin to form small brown and brick red sports on the lower canopy of the leaves that will begin to turn into lesions. Asian Soybean Rust produces two types of lesions. Lesions