Producers Warned To Keep Ahead Of Asian Soybean Rust

Matthew E. Baur, Griffin, James L., Padgett, Guy B., Lanclos, David Y., Coolman, Denise  |  1/12/2006 1:50:36 AM

LSU AgCenter Vice Chancellor Paul Coriel speaks to producers during the 2006 Tri-State Soybean Forum held in Delhi Jan. 6. About 200 people attended the forum, which featured speakers from the LSU AgCenter, the University of Arkansas and Mississippi State University. Topics covered during the forum included Asian soybean rust, the importance of verification programs and other subjects of interest to soybean producers.

News Release Distributed 01/11/06

DELHI – Experts say Asian soybean rust is here to stay, which means producers will have to maintain vigilance over their crops to keep the fungus at bay.

That was the message delivered to about 200 participants in the 2006 Soybean Tri-State Soybean Forum held here Friday (Jan. 6) by experts from the LSU AgCenter, University of Arkansas and Mississippi State University.

During the forum, soybean producers were encouraged to keep ahead of the rust to prevent it from becoming a bigger problem for American producers.

"It’s important to keep up with fungicide applications," said Dr. Boyd Padgett, a plant pathologist with the LSU AgCenter. "Once you get behind, it’s a lot harder to catch up."

Proper timing of fungicide applications and using proper equipment are necessary for managing rust, according to Padgett.

"Producers need to be sure they apply fungicides when they are supposed to and use the correct (spray) nozzles to ensure adequate coverage," he said, adding that a recent detection of soybean rust in Texas should concern Louisiana producers.

"Soybean rust thrives in warm, wet weather," Padgett said. "And wind patterns normally blow from the West. Because of the warm temperatures we’ve been having, producers should be extra cautious when examining their fields now."

Dr. Cliff Coker of the University of Arkansas agrees with Padgett.

"This (rust) is a problem we’re going to have to deal with from now on," Coker said. "Early detection is critical. This is one disease producers can’t afford to get behind on."

If a producer thinks soybean rust is present in a field, Coker says to call the local county agent and get an expert’s opinion.

"It’s better to be safe than sorry," he said.

Asian soybean rust was first detected in the United States when it was discovered in a Louisiana field in November 2004. Later investigation regarding the plant disease that previously had come no closer to the United States than South America showed it existed across the southern part of the country.

Rust first shows up as very small brown lesions or specks on the upper leaf surface in the lower plant canopy of soybean plants. To identify the lesions, suspected leaves should be held toward a bright light source, which should allow observers to make an initial identification of the disease. A professional can use a hand lens to look for raised pustules on the lower leaf surface.

In addition to soybean rust, the red-shouldered stink bug, or "Piezodorus guildinii," is another pest soybean producers were warned about during the forum. Dr. Matthew Baur, an LSU AgCenter entomologist, said yield reductions can result from this pest.

"These stinkbugs damage soybeans by reducing yield and quality," Baur said. "They also can cause problems with leaf retention."

The adult of this bug is light green and a little more than a half-inch long – about three-fourths the size of an adult southern green stink bug. They have a reddish-orange band across the back, right behind the head.

The LSU AgCenter recommends using Acephate to control the red-shouldered stink bug and Baythroid to suppress it, Baur said.

Other pests Baur warned about include the bean leaf beetle, the three-cornered alfalfa hopper and the soybean looper.

The use of harvest aids also was discussed. Dr. Jim Griffin, an LSU AgCenter agronomist, said the decrease in costs associated with machinery wear and labor and the increase in grade may warrant the use of harvest aids, especially in early maturing Group 4 varieties.

"Application timing is critical," Griffin said. "Gramoxone or sodium chlorate should be applied once the plant reaches physiological maturity. This is when the seeds in the pods in the top of the plant have filled the pod cavity and are beginning to separate from the pod wall. Application too early can result in decreased yield because of low seed weight. Allow 10 to 14 days between application and harvest to maximize leaf drop."

Recommendations made by LSU AgCenter experts are thoroughly tested and are significant of real life situations, the experts point out. One way this is done is through verification programs.

Dr. David Lanclos, an LSU AgCenter soybean and grain specialist, talked about the Louisiana Soybean Verification Program, which researchers use to develop recommendations they give to Louisiana soybean producers.

"This program was introduced in 1994 by Dr. Walter Morrison," Lanclos said. "Since that time, more than 114 fields in 20 parishes have been involved."

Historically, fields in the program have averaged 12.2 bushels per acre higher than the state average. The objective of the program is to demonstrate to cooperators that by following the LSU AgCenter’s research-based recommendations, yields can be maximized on large farming operations.

The program is supported annually through donations of seed, chemicals and equipment and is funded by the Louisiana Soybean Research Grain and Promotion Board.

To help Louisiana soybean producers grow more profitable crops, the LSU AgCenter has several publications available on its Web site at These publications include The Soybean Handbook, Publication 2624, and Soybean Variety Recommendations, Publication 2269, which are available in print, as well. For printed copies, call the LSU AgCenter Communications Office at (225) 578-2263 or e-mail Another publication, Control Soybean Insects 2005, Publication 2211, also is available on the Web site only.


Matthew Baur at (225) 578-1822 or
Jim Griffin at (225) 578-1768 or
David Lanclos at (318) 473-6530 or
Boyd Padgett at (318) 473-6530 or
A. Denise Coolman at (318) 547-0921 or

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