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Posted 8 June 2009. PMN Crop News.

Soybean Rust Still Not in State But Is Nearby

Mississippi State University.

Mississippi State, Mississippi (May 28, 2009)–Soybean rust is active on kudzu in Alabama and Louisiana, but the disease has not made it to Mississippi, although rains are creating ideal conditions for its development.


Tom Allen, a plant pathologist with the Mississippi State University Extension Service and the Mississippi Agricultural and Forestry Experiment Station, helps monitor for this disease.

“Rust is active in Louisiana and present but not spreading in Alabama and Florida, but there are no active threats to the state right now,” Allen said. “Conditions are right for the disease to develop in the state, but so far we have no indication of its presence.”

Malcolm Broome is a sentinel plot manager and scout with MSU’s Department of Entomology and Plant Pathology. He is one of three scouts who check systematically for signs of the disease each week in the state’s remaining 21 sentinel plots, key kudzu patches, and commercial soybean fields. This scouting information allows producers to make informed management decisions if rust threatens their crop.

“We got our sentinel plots planted March 1-2. That’s early for soybeans, but we want them to be at least 30 days ahead of the producers’ beans,” Broome said. “The plots essentially are located in counties around the border of Mississippi.”

Broome said the plots are planted with early and late maturity group IVs, a group V and a group VII.

“Both plantings of the group IV beans were blooming last week. The beans become more susceptible to rust after the bloom stage,” Broome said. “From here on, the beans in the sentinel plots will be in the optimum growth stages for rust infection, so they will show us if the disease has made its way to Mississippi.”

Broome said rust can be detected in a field about two weeks after exposure. Because of the spores’ presence in neighboring states, Broome and the other scouts are continuing to monitor the situation and scout Mississippi carefully. Hot, dry weather limits the development of the fungus and spread of the disease, but moisture and cool temperatures promote it.

“We’ve placed our sentinel plots where rust made early appearances last year and in places that provide ideal conditions for rust,” Broome said. “We’re trying to detect rust before it gets to producer fields.”

Producers provide the land for the sentinel plots, but scouting and monitoring efforts are expensive.

“The Mississippi Soybean Promotion Board funded us quite generously and made up for the funding shortfall this year,” Allen said.

Dr. Tom Allen