Soybean rust

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%. In 2002, USDA reported 10-60% of yield losses in South America and Africa.

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, leguminous forage crops such as trefoil and sweet clover and weeds such as kudzu.