Facts about Asian soybean rust
Some facts and figures about Asian soybean rust:
NAME: Phakospora pachyrhizi, commonly known as Asian soybean rust.
DISCOVERED: Rust is believed to have originated in Australia. It was first spotted in the United States in 1994, when it was found in Hawaii. The first discovery in the continental U.S. mainland was late in 2004 in Louisiana and the disease was found in 138 counties in nine states in 2005.
SYMPTOMS: First appears as small, irregularly shaped spots on the leaves of soybean plants. The spots gradually increase in size and turn brown or reddish as the disease progresses. Soybean rust causes premature leaf loss, leading to a smaller number of bean pods, fewer seeds per pod, and early maturity, all of which adds up to lost crop yield.
TREATMENT: The disease usually infects lower leaves first and moves up the plant, so scouting involves reaching to the lower leaves and using a magnifying glass to search for signs of the rust spores. Several plant fungicides have proved effective in counteracting soybean rust, but they must be applied immediately after the disease is detected and at its early stages of infection.
Sources: U.S. Department of Agriculture, National Soybean Research Laboratory, University of Illinois Extension.