DATE: 1/14/05

CONTACT: Dr. John Mueller, (803) 284-3343, ext. 223

WRITER: Tom Lollis, (803) 284-3343, ext. 241

S.C. soybean growers told to take Fife approach with rust: ‘Nip it!’

BLACKVILLE – Asian Soybean Rust, a disease that can defoliate a field of beans within two weeks, left its calling card in South Carolina late in the growing season in 2004, blowing in from South America on Hurricane Ivan too late to affect the crop.

While nothing is certain, Clemson University scientists fear that, like the movie killer machine in “The Terminator,” rust “will be back.”

“It’s not a disease you can take a ‘wait and see’ attitude with,” said John Mueller, Extension and research nematologist at Clemson University’s Edisto Research and Education Center, where about 50 Extension personnel, industry representatives and a few growers met Jan. 11 to hear about strategies for dealing with rust.

“You have to follow Barney Fife’s advice and ‘nip it in the bud,’” said Mueller.

“Beans are susceptible to rust the second they come out of the ground,” he said. Fortunately South Carolina will begin the 2005 season clean, since the fungus that was found in several locations last fall is expected to be killed by cold winter temperatures.

Unfortunately rust will probably survive in places where winters aren’t as harsh, like south Florida and the Rio Grande Valley in Texas.

“If it can blow in from Brazil, it’s no problem to come in from Orlando,” said Mueller.

He said that growers who can’t afford up to $24 for two fungicide sprays should think twice about growing soybeans. Only producers who traditionally make good yields – 25-30 bushels an acre and more – should plant soybeans this year. Fungicides are the only way to fight the fungus, since no resistant or tolerant variety has been found. The two-spray scenario applies only if the fungus arrives after flowering.

“If we’re at flowering in mid-July and rust doesn’t show up until mid-August, then one spray with a combination of protective and curative fungicides will go a long way,” Mueller said.

“If the fungus shows up early, however, control will require more than two sprays, which will not be profitable,” he said. “A grower could still lose his crop. In that case, he could still be protected if he has crop insurance. To collect, however, he will have to properly apply the appropriate fungicides.”

Of the 540,000 acres of soybeans planted in South Carolina last year, 458,459 were insured, according to Charles Curtis, Clemson Extension agricultural economist.

Protective fungicides labeled for use on soybeans include Quadris and Headline from the family of chemicals known as strobilurins. Bravo, a chlorothalonil product, is also registered. Other chlorothalonil products available are forms of Equus and Echo.

Emergency section 18 labels have been approved or are pending for the following curative fungicides, which are locally systemic: Tilt, Propimax, Bumper, Folicur, Loredo, Stratego, Pristine and Domark.

Rust puts growers between a rock and a hard place, according to Mueller. Many are reluctant to plant corn because nitrogen costs are so high and prices are poor for cotton.

“If not for rust, you would probably see a significant increase in soybean acres this year,” he said. “With rust, acreage could drop. How much remains to be seen.”

David Howle, assistant director for Regulatory and Public Service Programs at Clemson, said that controlling rust will be made even more difficult by the fact that more than 90 species of legumes serve as hosts. Kudzu is a host, and it is found across most of the state.

He said that the federal Animal and Plant Health Inspection Service (APHIS) plans an Internet-based system for communicating rust updates during the growing season. Updates will be provided weekly or more often as needed.

“Clemson will establish plots to monitor for rust’s arrival, and the impact it may have on edible beans, winter legumes and wildlife food plots and the impact those crops may have as inoculum generators,” Howle said.

Meg Williamson from the Plant Problem Clinic at Clemson said that producers and county agents who send suspected rust samples for laboratory diagnosis need to follow proper protocols to get good results.

“Place leaves between dry paper towels or sheets of paper to keep them flat and double bag them in plastic bags,” she said. “Keep the samples cool or at ambient temperatures until refrigeration is available.”

Williamson said that it will be important to make certain the outsides of the sample bags aren’t contaminated with spores.

“Wipe the bags and your hands, because people can be carriers of rust, too,” she said. Good records are important. Record the date, host plant, and the collector’s name, the exact location of the field and the location of the sample within the field on PPQ Form 391, which will be available through Clemson Extension offices.

The meeting at Edisto REC was just the first of several scheduled for growers and others in agriculture during January to update the rust situation. Meetings were held Jan. 13 at the Pee Dee REC and in Alcolu.

Other meetings are scheduled for Jan 18 at 9 a.m. at the Tractor Pull Arena in Saluda and at 2:30 p.m. at the Furman Methodist Church Social Hall in Furman; Jan. 19 at 9 a.m. at the Ramada Inn in Santee, at 2 p.m. at Young’s Plantation in Florence, and at 6 p.m. at the Charcoal Grill in Dillon; Jan. 20 at 9 a.m. at the Horry County Extension office in Conway and Jan. 24 at noon at the State Cotton Museum in Bishopville.

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