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Posted 19 November 2004. PMN Crop News.

Soybean Rust Confirmed In Florida

Florida Department of Agriculture and Consumer Services

Tallahassee, FL (November 17, 2004) - Florida Agriculture Commissioner Charles H. Bronson announced today that a U.S. Department of Agriculture (USDA) laboratory in Beltsville, MD confirmed soybean rust on samples taken from an experimental test plot managed by the University of Florida/Institute of Food & Agricultural Sciences (UF/IFAS) in Quincy, Florida. The disease was also found and confirmed several days earlier in Louisiana and Mississippi. These southeast U.S. discoveries are the first occurrences of soybean rust in North America. Pathologists strongly suspect that Hurricane Ivan that hit the panhandle of Florida in mid September is responsible for the spread of the disease from South America.

UF/IFAS extension agents were prompted to look in their soybean test plots because of notification by Louisiana State University that soybean rust had been found in their extension service test plots.

The soybean rust pathogen (Phakopsora pachyrhizi), which is easily spread through wind-borne spores, is a fungus that causes small pustular lesions on the foliage and pods of soybeans and several other legume hosts, including lima beans. Soybean rust also infects kudzu, the exotic nuisance weed that has spread throughout Florida. While the health of the kudzu plant is not severely impacted by the disease, it serves as a reservoir for the soybean rust pathogen. Forage legumes, such as yellow sweet clover also serve as a refuge for the pathogen in the off season.

The disease was first recorded in Japan in 1903, and identified for the first time in the Western Hemisphere in Hawaii in 1994. Severe outbreaks in the last few years in South America have heightened concern for the spread of the disease to the North American soybean growers. In other countries, it is not unusual for this pathogen to reduce yields by half or more.

Florida grows approximately 11,000 acres of soybean. While this is the first instance of soybean rust to be found in the United States, the detection comes at a time when most soybeans have been harvested in the state. As a result, the impact of the fungus this season should be minimal. The timing also gives the Department, USDA, and UF/IFAS scientists time to prepare a management strategy for the 2005 crop year.

The Department is working jointly with the University of Florida/IFAS and the USDA to mobilize survey efforts to immediately determine the extent of the disease occurrence, coordinate diagnostic activities and conduct training of both surveyors and growers for accurate detection of the disease.

Current management strategies include emphasis on early detection and timely fungicide applications. Over time, soybean rust-resistant varieties may become available.

A coordinated approach will be required by all soybean producing states to effectively manage this disease.

Typical symptoms on leaves include raised, small brown pustules on the undersurface of the soybean leaf as seen in the attached photos. If you think your plants may be infected with soybean rust, we urge you to visit our Web site to learn more information about the disease and to call the Departmentís toll-free helpline number at (888) 397-1517 to arrange for an inspection of your plants.


Denise Feiber
(352) 235-0036 (cell)