Orange rust has been discovered in Louisiana sugarcane. (Photo by Kenneth Gravois. Click on image for downloadable version.)

News Release Distributed 07/09/12

A sugarcane disease new to Louisiana has been identified in two Louisiana fields, according to experts from the LSU AgCenter.

The disease, orange rust, was first identified in the United States in 2007 in Florida, said LSU AgCenter plant pathologist Jeff Hoy.

“We’ve been expecting this disease for several years,” Hoy said. “Now, it has been found.”

The disease is similar to another sugarcane disease, brown rust, Hoy said. It differs by the orange color of leaf lesions and spores the pathogen produces.

The orange rust was detected at low levels in the variety Ho 05-961 at two locations, he said. Researchers and agents are surveying fields to determine if additional sites are infected.

“This is a low level of infection,” Hoy said. “We don’t know what will happen over time.”

The variety, Ho 05-961, has been shown to be susceptible to the disease in plantings in Florida, he said.

Preliminary resistance ratings are available for commercial sugarcane varieties.

The orange rust was found and verified by technicians in the U.S. Department of Agriculture-Agricultural Research Service pathology project under the direction of Mike Grisham.

Agriculture and Forestry Commissioner Mike Strain, D.V.M., said the LDAF has already secured Section 18 exemptions on two fungicides for control of orange rust in sugarcane.

“Once the extent of orange rust has been established, we will tailor a plan to combat the disease,” Strain said.

Rick Bogren