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Soybean rust in state, no action to take now
MISSISSIPPI STATE -- Agriculture officials confirmed the existence of soybean rust in Mississippi Nov. 16 after the fungus was found in one field in Adams County.
Rust was confirmed in Louisiana Nov. 10, and officials immediately increased systematic efforts to search for the soybean disease in Mississippi. The Mississippi Department of Agriculture and Commerce announced its finding Nov. 17. Florida also confirmed rust on Nov. 17.
"Four of five samples taken during an inspection tour in Louisiana and Mississippi on Thursday, Nov. 11, were confirmed today by officials at the U.S. Department of Agriculture as Asian soybean rust, a potentially devastating disease," MDAC said in its announcement. "Based on predictive weather models and spore dispersal patterns, Animal and Plant Health Inspection Service and Agricultural Research Service scientists believe the introduction of the fungus here in the United States was caused by a wind-blown event related to the unusual hurricane season."
Billy Moore, plant pathologist emeritus with Mississippi State University's Extension Service, said the rust was found in a soybean field about 10 miles south of Natchez. It is the only rust confirmed in the state as of Nov. 17.
After soybean rust was confirmed near Baton Rouge, officials concentrated their search around that area. Officials searched the path Hurricane Ivan took in the state, and Moore said the rust found was in the wind path of the hurricane suggested by a computer model.
"Do not panic. That's the main message right now. We do have rust, and yes, we can do something about rust," Moore said. "If they can do something about rust in South America and Africa, we can, too."
While no one in the business wanted rust to arrive, Moore said its arrival at the end of the growing season gives scientists and producers all winter to plan the course of action. A main tool in the upcoming fight will be another round of sentinel plots, or fields of soybeans planted well ahead of any normal planting date and aligned across the state. Weather permitting, Moore said these will be planted March 1.
"We'll monitor these at least once a week, perhaps even more. We'll also monitor soybean fields once farmers start planting," Moore said. "If we find rust, we'll trigger fungicide applications in our soybeans."
Early planted varieties should give growers an advantage in the fight against soybean rust. The fungus cannot overwinter in much of the country, which means it must move in from southern regions each year. Early soybeans might be able to stay in large part ahead of the disease each year.
Alan Blaine, Extension soybean specialist, said the only thing producers can do now is wait.
"We're gathering additional information every day. We have all winter to keep folks tuned to what they need to do," Blaine said. "They probably will hear a lot of mistruths, so they should stay tuned to what's coming out of local universities that are working with state departments of agriculture, the U.S. Department of Agriculture and APHIS."
Alan Henn, Extension plant pathologist, said he and MDAC representatives submitted paperwork earlier this year to the Environmental Protection Agency seeking a special use exemption for certain fungicides that battle rust. Mississippi was one of a group of states that applied together for these permits.
"The approvals for these have been dribbling in over the summer. As EPA gets their data, everyone who applied gets the special use exemption," Henn said.
To date, the state can use approved Section 18 exemption materials, including propiconazole, sold as Tilt and Propimax EC; tebuconazole, sold as Folicur; and myclobutanil, sold as Laredo EC. Henn said the state still awaits exemption to use a fungicide mix of propiconazole and trifloxystrobin, sold as Stratego. Other fungicides that have soybean rust on their regular labeling include azoxystrobin, sold as Quadris, and chlorothalonil, sold as Echo. BASF expects their active ingredient, pyraclostrobin, sold as Headline, to receive full label status by December.