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University, Extension workers mount campaigns against soybean rust

If Asian soybean rust slips up undetected on Mid-South farmers in 2005, it won’t be due to a lack of trying by Mid-South Extension Service and university specialists.

From early-planted sentinel plots to county agent scouting to sophisticated testing for rust proteins, university and Extension personnel are preparing for one of the most intensive manhunts, or rust hunts, ever mounted in U.S. agriculture.

Given the ample warning from last November’s discoveries of soybean rust, specialists spent the winter conducting extensive training sessions, preparing publications and Web sites and planning early warning systems for the disease.

Most states will be participating in a national soybean rust plant disease surveillance and monitoring network being organized by USDA’s Animal Plant Health Inspection Service and other agencies. But some states are busily setting up sentinel plot networks of their own.

“We kept hearing about the sentinel plots coming down from APHIS,” said Alan Blaine, Extension soybean specialist with Mississippi State University. “We didn’t think they were coming fast enough, so we decided we had better go ahead and do something.”

Blaine said the Mississippi Extension Service will have 17 sentinel plots going from north of Mobile Bay across to the Louisiana line in south Mississippi. Eleven of those had already been planted when Blaine spoke at the Mid-South Farm and Gin Show in early March.

“Louisiana is doing the same thing, and I talked to a gentleman at Auburn who is going to be doing this also,” said Blaine. Other plots will be located south of I-20 and along the Mississippi River from Natchez to the Tennessee line at 50- to 100-mile intervals.

The Arkansas Extension Service is locating 56 sentinel plots across the state with a “high concentration” in the Delta, the Grand Prairie region and in southeast and southwest Arkansas, said Chris Tingle, Extension soybean specialist with the University of Arkansas.

“These will be monitored weekly or bi-weekly throughout the season to help determine when and if soybean rust shows up,” said Tingle, who also spoke at a soybean rust seminar at the Gin Show.

University of Missouri specialists will be trying a slightly different tack, according to Allen Wrather, plant pathologist with the university’s Delta Center at Portageville, Mo.

“With funding from checkoff dollars, county Extension agents will be scouting a field every 30 miles each Monday, Wednesday and Friday,” he said. “As soon as they find something, we’ll have people stationed there for the next three or four days to show you what rust looks like.

“There won’t be any speeches or anything like that. You can ask questions, and we’ll show you what we’ve found.”

University of Tennessee scientists will plant between 30 and 50 sentinel plots and monitor them for soybean rust symptoms throughout the growing season, said Melvin Newman, Extension plant pathologist with the West Tennessee Experiment Station in Jackson, Tenn.

“We plan to have an extensive network that will go all the way from the Smoky Mountains to Memphis,” said Newman. “In fact, that’s where we found the first rust in Tennessee, in Memphis.”

Newman said University of Tennessee researchers will take their surveillance a step further and will run soybean leaves from the sentinel plots through a DNA test called a PCR. The testing will be funded by a grant from the Tennessee Soybean Promotion Board.

“The PCR test can detect extremely small amounts of rust,” he said. “If there is any rust protein there, even if it is barely detectable with the naked eye or even a microscope, PCR can find it. Hopefully, that will provide our growers with a few extra days to prepare for applications of fungicides.”

Blaine said Mississippi’s sentinel plots are being planted earlier than the normal planting dates for the state’s soybean crop. “If we can find it, hopefully we can give you a two- to three- or four-week heads up on what we’re seeing.

“We’re planting a late Maturity Group 3, a late Group 4, a mid Group 5 and a late Group 5,” he said. “That will give us a very long reproductive period, which the USDA specialists say is the most susceptible timeframe for soybean rust.”

Mississippi State University plans to go back three weeks after the first plots go in and do an additional plantings with the same maturity groups.

Tingle said his state formed an Arkansas Rust Working Group consisting of plant pathologists, Extension and Experiment Station researchers, agronomists and IPM coordinators in 2003.

“Once the disease was confirmed in the United States last November, we began a tremendous educational effort for first detectors,” he said. “We conducted 10 training sessions that has reached over 500 people consultants, seed salesmen, chemical consultants and so on.” (Funding was provided by the Arkansas Soybean Promotion Board.)

Blaine said Mississippi specialists have also been conducting training sessions and preparing a soybean rust bulletin and developing a rust Web site to help prepare farmers for dealing with the disease.

“One thing that concerns us is scouting for this disease,” he said. “I think Monte Miles will tell you this is a very difficult disease to scout for and to recognize. I don’t think producers are going to be able to do that, and we hope the sentinel plots we have in the South will help us.”

(Blaine was referring to Monte Miles, plant pathologist with USDA’s Agricultural Research Service, who also spoke at the seminar in Memphis.)

Newman said because Tennessee farmers have become accustomed to spraying for other soybean diseases, applying fungicides for Asian rust may not take much of an adjustment.

“We have a whole array of other diseases, including frogeye leaf spot, anthracnose and brown spot,” he noted. “We’ve been spraying for these diseases for many, many years, and, in some counties, we have as many as 50 percent of the acres already being sprayed.”

The fungicide applications have helped growers harvest 5 to 15 bushels more of soybeans per acre, he said. “Most of our farmers know that if an application has to be made, they will make their money back on that first application.”

Although soybean rust may be one of the most devastating diseases farmers have faced, farmers don’t have many options for dealing with it.

“In my view, you will have three choices to make,” said Wrather. “You can decide to ignore it, and, hopefully, you won’t do that. You can decide that when it’s in the area you will spray every soybean plant that’s blooming. Or you can decide to come see what it looks like and scout your own fields and make the decision that’s most appropriate.”


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