The Rapid Movement of the Soybean Rust Pathogen
Soybean rust, caused by the fungus Phakopsora pachyrhizi, results in soybean yield losses of up to 80%. Rust diseases are named for the orange powdery spores produced in leaf pustules. They are easily airborne from plant to plant.
Although the disease does not occur in the continental U.S.A., projected losses of $7.1 billion per year were estimated in a 1984 economic risk analysis. The first report of the disease was from Japan in 1902. By the 1950s the disease was reported in most Asian countries. It was not until the 1990s that the disease was confirmed in the Western Hemisphere. The first report was from Hawaii in 1994. The disease was first found in South America after 1999 and is now in four countries. The continental U.S. is the only major soybean producing area in the world where soybean rust has not been found.
The rapid spread of P. pachyrhizi and its potential to cause severe yield losses makes this the most destructive foliar disease of soybean and could have a major impact on soybean production in the U.S.A.
