Research On Cotton Corn and Soybeans Highlighted At Dean Lee Field Day

Tobie Blanchard  |  8/26/2006 1:54:36 AM

LSU AgCenter soybean and corn specialist Dr. David Lanclos reported on Asian soybean rust, aerial blight and Cercospora leaf blight during the AgCenter's Dean Lee Research and Extension Center Row Crop Field Day Aug. 24.

News Release Distributed 08/25/06

Participants heard about a variety of studies involving cotton, corn and soybeans during the Dean Lee Research and Extension Center Row Crop Field Day Thursday (Aug. 24).

The field day focused on weed control in cotton, corn and soybeans, as well as defoliation and insect control methods in cotton production. The participants also heard about the disease that has been on many researchers’ and soybean growers’ minds – Asian soybean rust.

"Rust is real," Dr. David Lanclos, LSU AgCenter’s soybean and corn specialist, told producers.

Asian soybean rust has been confirmed in eight Louisiana parishes.

"This weather is perfect for the development of rust," Lanclos said, referring to conditions of low humidity, high moisture and moderate temperatures.

Lanclos commended soybean growers for being vigilant and using preventative spraying to stop rust from spreading.

"We can control rust," he said. "But we have got to spray."

Around 50 percent of Louisiana’s soybean crop has been harvested, but Lanclos warned, "There is still a tremendous amount of acres out there that are still vulnerable to rust."

Lanclos reminded growers there also are other diseases that threaten soybeans. "We have other diseases that if left untreated are just as bad as Asian soybean rust," he said. "I’m talking about aerial blight and Cercospora leaf blight."

While diseases concerned soybean growers, insects are the worry for cotton growers, according to experts.

"2006 has been the most demanding year from an entomology standpoint," LSU AgCenter entomologist Dr. Ralph Bagwell said during the field day.

The tarnished plant bug has been a problem for some growers, but their populations vary greatly from field to field.

"You can have 800 acres with just one tarnished plant bug, and then you see them in high densities in a 4-foot area," Bagwell said.

Bagwell said he is trying to answer questions on sampling of insects, control issues and thresholds.

"Thresholds are very dynamic this year," he explained. "We have periods when we need to get good control and others times we don’t need that much."

Defoliation is another topic important to cotton growers and critical to a good harvest.

"By taking off the leaves, you facilitate spindle picking, you take trash out of the cotton and you generally get better grades," said LSU AgCenter cotton specialist Dr. Sandy Stewart.

Stewart told cotton growers what worked last year or even yesterday may not work today.

"Defoliation is more like an art rather than a science," Stewart said. "There are many chemical combinations available, but environmental conditions are a factor in defoliation."

Every year is different as to how the cotton will respond to the chemicals, and temperature plays a big role in how the leaves drop, Stewart explained.

In Louisiana, growers usually have to make two applications of defoliants, with the first application 12 days to 14 days before harvest and a follow-up application about a week after the first application.

Stewart also encouraged growers to take a hard look at variety evaluations from different sources. He said looking at all the data will help them make informed decisions when planting.

Producers also heard from researchers about weed control. Glyphosate-resistant weeds are becoming a problem in other states, and LSU AgCenter researcher Dr. Donnie Miller warned growers it could happen here.

"We need to stay on top of this," Miller said. "The problem is compounded with the overuse of glyphostate."

Miller encouraged growers to use a variety of herbicides. He also spoke to growers about volunteer weeds in Roundup Ready crops.

"You need to be aggressive in taking these weeds out when they are small," Miller said.

Dr. Steve Moore spoke to producers about his research on reducing aflatoxin and performance test evaluations. Moore is looking at the effects of glufosinate on corn. Glufosinate is an herbicide that causes plants to produce ammonia, and the ammonia can cause aflatoxin to break down.

Moore collected data from his performance tests and discouraged soybean growers from growing maturity group III soybeans.

"Group IIIs will always put you at a yield disadvantage," Moore said. "I don’t know a time when you wouldn’t be better off planting another group."

Approximately 170 growers from across Central Louisiana attended the field day.


Writer: Tobie Blanchard at (225) 578-5649 or

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