Farmers growing soybeans this year should be on alert, but not panicked, after last week’s discovery of Asian soybean rust in a kudzu patch in Iberia Parish.
“Right now, it’s just sit and watch and wait,” said Dr. Clayton Hollier, LSU AgCenter plant pathologist. “We’re telling them it’s a little too early to do anything.”
Whether Asian soybean rust is a major problem in Louisiana this year depends on the weather, Hollier said. Regular rainfall in South Louisiana so far this spring could set the stage for the disease to spread. Rust did not show up last year until late in the growing season because of the dry summer.
“As we continue to have those showers, the more chances are of having problems this year,” Hollier said, adding that if the disease becomes a significant problem, farmers may have to use two applications of fungicides, considerably reducing profits.
“Just the fact that it was found so early compared to last year is alarming,” Hollier said.
The first discovery of 2006 was 53 days later than the confirmed finding of Asian soybean rust in kudzu this year.
Soybeans that have emerged are still in the vegetative phase, and ASR is more of an issue for the later reproductive stages, he said, noting that monitoring for the disease goes on year-round.
“We’re doubling our efforts now,” he said.
Several other fungal diseases, such as aerial blight, cercospera and pod stem blight, are also devastating for soybeans.
“I don’t want people to forget about those diseases just because this disease has raised its ugly head,” Hollier said, adding that farmers across the state treated their crop for those diseases last year, and the effort probably was a factor in suppressing Asian soybean rust.
Hollier said his research associate, Rose Berggren, found the rust on May 8 in an area where it was found last year, but he said confirmation of the disease was necessary before releasing word of the discovery.
“Because of these implications and the fact that our strategies may have to change because of ASR’s earlier presence, the delay in announcement has everything to do with making certain that the diagnosis was correct. Initial microscopic observations indicated to us that ASR was present, but there were some abnormally shaped spores present,” he said.
Adding to the delay was the requirement that two separate tests be used to confirm the disease.
“Future diagnoses will not take so long because of our knowledge of ASR presence,” he said.
The U.S. Department of Agriculture (USDA) reports that in addition to the Iberia Parish find, Asian soybean rust has been detected in 10 counties in Florida and five counties each in Georgia and Alabama.
According to the USDA, soybean rust is still active in six counties in Florida. Conditions in Louisiana are wetter than those in Florida, where most of the state is under drought conditions. The disease was also detected on soybeans in one county in Texas, but that field has since been cultivated and planted with corn.
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