Jason Jenkins
Senior Information Specialist
573-882-2980
JenkinsJL@missouri.edu
May 27, 2004
Don’t let your soybean disease
knowledge get ‘rusty,’ says MU specialist
Though soybean rust has not yet been reported in the continental United States, its arrival could have significant impacts on U.S. soybean yields, said Laura Sweets, extension plant pathologist with the MU Commercial Agriculture Program.
“With all the press that soybean rust is getting, it’s sure to be on producers’ mind when they’re out scouting fields this season,” she said. “It’s important they remember that we have foliar diseases that could be mistaken for rust, and that those diseases can be managed.”
Even for a trained pathologist, identifying Asian soybean rust in the field can be difficult. Sweets herself found it troublesome earlier this year when she attended the World Soybean Research Conference in Brazil.
“We took a soybean rust tour, and we started by looking at some research plots infected with rust,” she said. “We all felt confident that we could identify it based on those plots, but when we went out into actual production fields where rust wasn’t the only disease present, it was much harder to distinguish.”
Soybean rust symptoms include tan to reddish brown lesions, leaf yellowing and defoliation, Sweets said. “These also are symptoms of Septoria brown spot, bacterial blight, bacterial pustule and frogeye leaf spot, all of which are present in Missouri.”
She added that “hot spots” for these endemic diseases include fields where the disease was present the year before, river bottom fields, fields where air circulation is reduced by surrounding forested areas, and fields that “have been grown to soybeans in consecutive years without rotation.”
Producers who find diseased plants that they can’t identify should contact their local extension agronomist, who will help them send a sample to the MU Extension Plant Diagnostic Clinic in Columbia for positive identification.
“Rust has become widespread throughout Brazil and other South American countries in a very short period of time, and it’s theorized that wind currents will eventually bring the disease to the states,” she said. “The Brazilian producers I spoke with seem to be taking it in stride, and they’ve really adapted. I have no doubt Missouri producers also will adapt.”
The impact of soybean rust in the United States will vary greatly depending on when and under what weather conditions it arrives, Sweets said. “Moisture is the key. A growing season like we had across much of Missouri last year wouldn’t be conducive for rust.”
For more information about soybean diseases in Missouri, download the MU Integrated Pest Management publication, “Soybean Diseases,” which is online at http://muextension.missouri.edu/explorepdf/agguides/pests/IPM1002.pdf. Printed copies are available, for a small charge, from Extension Publications, 2800 Maguire Blvd., Columbia, MO 65211 or phone 1-800-292-0960.
The North Central Integrated Pest Management Center also has an online publication about Asian soybean rust, available at http://www.ncpmc.org/soybeanrust/.
Source: Laura Sweets (573) 884-7307
| Return to Current News Releases | |
|
College of Agriculture Food and Natural Resources
AgEBB |