Clayton Hollier, Schultz, Bruce | 9/19/2006 2:19:52 AM
LSU AgCenter scientists confirmed Monday (Sept. 18) that Asian soybean rust has been detected in a commercial field in Assumption Parish – the 13th Louisiana parish where the disease has been found this year.
Dr. Clayton Hollier, an LSU AgCenter pathologist, said leaves of some of the plants in the 60-acre field were completely covered with the disease, but the crop is far enough along that the disease won’t have any overall impact.
"It’s almost ready to be harvested," Hollier said.
The late occurrence of Asian soybean rust this year means the disease has had minimal effects where it’s been found throughout the state, Hollier said.
"None of it is to the degree that it is a threat to yield," he said.
Last week, the disease was found in a research plot in Jefferson Davis Parish and in a commercial field in Iberville Parish.
Regarding one of those cases, Hollier said the research plot where the disease was found had not been sprayed with a fungicide, but adjacent plots that had been treated with fungicides didn’t have rust.
The Iberville Parish field had been abandoned for problems not related to rust, he said.
Other parishes where the disease has been found include Iberia, Lafayette, St. Mary, Washington, Avoyelles, Rapides, Natchitoches, Catahoula, Concordia and Tensas.
Not all of those discoveries were in soybean production fields, however. Asian soybean rust has been found in patches of kudzu and in sentinel plots intended to pick up early signs of the disease, Hollier said. Many discoveries were in moist, shaded areas, he said.
Other states where the disease has been found this year include Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina and Texas.
Hollier said dry weather in early summer could have helped delay the disease in Louisiana.
"If we had early showers, we might have seen it earlier," Hollier said. "The delay has been to the advantage of the growers."
He said many fields were protected after farmers took a proactive approach and sprayed fungicides as a preventive measure.
"I think that helped," he said.
Asian soybean rust, which spreads by windborne spores, has been around since the early part of the 20th century, but it had been confined to Asia until fairly recently – when it spread to Africa and then on to South America.
Since the first discoveries in the Western Hemisphere in 2000, the disease has proven to be devastating to soybean crops in Brazil. So far, however, since first moving into the United States in 2004, outbreaks in Louisiana have come relatively late in the growing season and haven’t had significant effects on the state’s crop, experts say.