(12/04/24) BATON ROUGE, La. — A disease called false smut is posing a growing threat to the global rice crop, and LSU AgCenter scientists are part of an international group working to learn more about the problem.

Felipe Dalla Lana, a plant pathologist at the AgCenter H. Rouse Caffey Rice Research Station near Crowley, and Vinson Doyle, a mycologist based on the LSU campus in Baton Rouge, are working with colleagues from more than 20 institutions worldwide through the International Rice False Smut Consortium. They recently traveled to the International Rice Research Institute in the Philippines to meet with fellow consortium members for a workshop.

While false smut is not unheard of in Louisiana rice fields and has been in the state since at least the 1920s, the disease is not currently a major concern for farmers here. False smut can be found in many rice-growing countries and is particularly problematic in China and India. And the disease is expanding its range.

“In other parts of the world, we are seeing a shift,” Dalla Lana said. “Where this disease is usually not a problem, now it has become more prevalent.”

False smut, which is caused by a fungus that replaces the kernels of rice plants with fungal structures, reduces yields and quality. It is similar to kernel smut, which is more common in Louisiana.

Dalla Lana and Doyle — along with their research partners around the globe — want to find out why false smut, which was first discovered in India in the late 1800s, has become such a big problem lately.

Dalla Lana is researching the disease’s behavior and how factors like weather, soil and rice variety might affect it.

“What we are trying to do is understand why we have outbreaks, why we don't have outbreaks, what makes the shift from it being a minor problem to being a major problem,” he said.

Doyle plans to examine both historical and recent false smut-infected specimens to learn more about the disease, how it has changed over time and how it has spread around the world. He believes historical patterns can shed light on the disease and possible management strategies.

“Historically, this disease has been associated with really good harvests. When farmers in India saw this disease, they knew it was indicative that a ‘golden harvest’ was coming,” he said. “And there's been some associations with elevated nutrient levels. So maybe when you've got adequate nutrients in the soil and you get a good harvest, that also ends up inducing this disease to emerge.”

False smut damage seems to be worse in fields planted with high-yielding varieties, Doyle said. Many modern varieties grown in Louisiana have been bred with high yields in mind.

“What’s happening in other parts of the world, we can use as a warning for what might start happening here,” he said. “We certainly have to pay attention to it.”

Both researchers hope the work of the international consortium will uncover much-needed information about this emerging disease threat and speed up the process of identifying solutions.

“Because we work within the global research group, we can have data from different environments and different conditions that we cannot replicate here,” Dalla Lana said. “We can have a better understanding of the pathogen and try to anticipate changes that might happen here in Louisiana and have a plan before it becomes a major problem.”

“We've got dozens and dozens, if not more, questions that need to be answered. And oftentimes, one of those question takes a whole research lab several years to address,” Doyle added. “When you can put a team of researchers together like the several dozen that are in this consortium, you can start to tackle lots of different questions simultaneously.”

LSU AgCenter researchers are part of an international team studying false smut, a disease affecting rice. Photo by Felipe Dalla Lana/LSU AgCenter

Rice plants affected by false smut. Photo by Felipe Dalla Lana/LSU AgCenter

Felipe Dalla Lana, left, and Vinson Doyle, both of the LSU AgCenter, look at rice plants in a greenhouse while visiting the Philippines for an International Rice False Smut Consortium workshop. Photo provided by the International Rice Research Institute

Members of the International Rice False Smut Consortium recently gathered for a workshop at the International Rice Research Institute in the Philippines. Photo provided by the International Rice Research Institute