MISSISSIPPI STATE -- Soybean rust, a devastating fungal disease, was discovered Nov. 7 in the United States, but officials have not yet detected it in Mississippi.

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service announced Wednesday that it had confirmed Asian soybean rust in two Louisiana State University research plots near Baton Rouge. The disease was spotted Sunday and officially confirmed three days later. This is the first appearance of rust in the United States, which previously had not been found closer than Central America.

"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 across the country. As a result of the harvest, the impact of the fungus should be minimal this year," USDA said in its written announcement.

Alan Blaine, soybean specialist with the Mississippi State University Extension Service, said the arrival of soybean rust is significant, and experts hope the disease is confined to a very small area this year. He urged growers not to panic, but to wait until more information is known and a plan of action can be plotted.

"If it had to enter the United States, this is probably a much more opportune time than during the peak of the growing season," Blaine said.

As part of the early battle against soybean rust, Mississippi had six sentinel plots of soybeans on a line across the state from Natchez to Mobile Bay. These were surveyed bi-weekly along with patches of kudzu, a host for the disease, throughout this year's growing season.

"As of today, no incidence of rust has been detected in Mississippi," Blaine said. "We are conducting a survey down the Mississippi/Alabama line evaluating kudzu and some soybeans for rust. This is the path Hurricane Ivan took when it entered the United States, and this is the third survey of that path we have made since it hit in September."

Blaine said MSU officials will survey fields on the western side of the state Friday with officials from the Department of Agriculture and APHIS.

Soybean rust is a fungal disease spread by spores. It can be carried by wind for hundreds of miles, transported on people or machinery, or spread by infected plant material. Left untreated, it completely defoliates and often kills a plant, reducing yields by as much as 80 percent.

"Soybean rust can be managed with the judicious use of fungicides. However, early detection is required for the most effective management of soybean rust. Monitoring soybean fields and adjacent areas is recommended throughout the growing season," USDA officials said.

Officials believe this year's active hurricane season may have carried the spores to U.S. soil. Charles Wax, state climatologist at MSU, said 2004 was a very active hurricane year with 14 named storms. The long-term average is less than 10 named storms a year.

"Four of these storms made landfall as tropical storms and five were hurricanes when they landed," Wax said. "It was an above-average year, and the major reason was a combination of meteorological features that came into play just right."

These features aligned to draw tropical storms into the Gulf of Mexico and then north to make landfall in the United States. Wax said some hurricane season analysts predict that these controlling conditions will remain similar for the next several years, potentially keeping the number of land-falling hurricanes above normal.

Agronomists knew it was simply a matter of time before the disease made its appearance in the United States, but it arrived sooner than they anticipated. They had hoped for more time to develop resistant soybean varieties.

There are two strains of soybean rust, but only an aggressive Asian strain is a threat to the United States. The Asian strain was discovered in Japan in 1902 and quickly spread throughout the rest of Asia. It moved to Australia, and from there to Africa in 1996. A cyclone spread rust to the rest of the continent's soybean-growing areas shortly after it arrived in Southern Africa.

In 2001, it was found in South America, and now Brazil, Argentina, Paraguay and Bolivia are fighting the disease.