Brooks Blanche, LSU AgCenter agronomist, is conducting research on cotton varieties and looking for resiliency across planting dates. (Photo by Bruce Schultz)

Karl Harborth, LSU AgCenter animal scientist, is beginning a study on less stressful weaning methods for Louisiana cattle. (Photo by Bruce Schultz)

Ron Levy, LSU AgCenter soybean specialist, holds up soybean plants for comparison at the Dean Lee Research Station field day on July 28. (Photo by Bruce Schultz)

News Release Distributed 07/29/11

ALEXANDRIA, La. – Nematodes love drought, and some Louisiana soybean and cotton farmers are having problems this year with these microscopic pests that eat away at plant roots.

“We’re in reniform nematode country,” LSU AgCenter agronomist Charles Overstreet told farmers gathered for the annual field day at the Dean Lee Research and Extension Center here on July 28.

The reniform nematode is prevalent across the middle of the state running through Alexandria. Both reniform and root-knot nematodes cause yield loss in the northeast quadrant of the state as well as along the Red River valley, which runs in a diagonal in the northwest part of the state.

Overstreet was one of 12 AgCenter scientists who presented the latest information from research on soybean, cotton and corn production and on cattle production.

The best protection against the build-up of nematodes is crop rotation, Overstreet said. The pests initially got their hold in Louisiana when farmers continuously planted cotton year after year. Once nematodes are established, they never go away. Fortunately, they don’t like corn as well as cotton or soybeans.

“One year of corn will knock them down,” Overstreet said, adding that two years of corn is a good idea for problematic fields.

A symptom of nematode presence is when a field has an “up and down” pattern, Overstreet said, with the stunting of a significant number of plants.

Overstreet recommends that farmers use nematicides – although timing is critical – to help kill this pest, which can cause major yield loss if left uncontrolled.

Daniel Stephenson, LSU AgCenter weed scientist, told the farmers to be on the lookout for herbicide-resistant johnsongrass. This is the latest weed to develop resistance to glyphosate (Roundup) herbicide, which is the herbicide used with Roundup Ready soybeans, which is the dominant type grown in Louisiana.

Weeds, including johnsongrass, had nearly disappeared from soybean fields with the advent of Roundup Ready soybeans 15 years ago, said Jim Griffin, LSU AgCenter weed scientist.

“We could be set back 25 years,” Griffin said. But he and the other AgCenter weed scientists are developing management strategies to help control johnsongrass and pigweed, the other weed that has been found resistant to glyphosate in Louisiana. Meanwhile, he asks that farmers who find johnsongrass in their fields after herbicide treatments report this to their county agents.

Sid DeRouen, LSU AgCenter animal scientist, gave preliminary results of a multi-state study on hair traits of cattle and the relationship to weight gain. So far, he has found that shorter hair with more luster seems to be a desirable trait to breed for.

Karl Harborth, AgCenter animal scientist, is studying two systems for weaning calves that have proven to be less stressful for animals, which, ultimately, affects their weight gain.

Fence-line weaning involves separating the calf from its mother in adjacent pastures with a good fence so they can still have nose-to-nose contact. The other involves a plastic clip inserted in the calf’s nose shortly before weaning so it can’t nurse its mother but can still eat grass and eat feed from a trough.

“Weaning is one of the most stressful events in a calf’s life. Anything that can be done to reduce this stress will be beneficial to your bottom line,” Harborth said.

Growing cotton this year in Louisiana has had its share of challenges, said John Kruse, LSU AgCenter extension cotton and corn specialist.

“Folks planted cotton with jackets on” because of the cool weather, which soon turned hot and stayed hot to create drought conditions, which are still continuing, he said.

Kruse said about 570,000 acres of corn were planted in Louisiana this year, compared to 510,000 acres last year.

Rogers Leonard, LSU AgCenter entomologist, said Temik 15G, the standard soil insecticide for cotton seedlings, has been removed from the market. That leaves insecticide seed treatments, which don’t have the residual control.

“We will be required put out foliar sprays as rescue treatments for treating thrips and cotton aphids in these seedling plants,” he said.

The best time for a foliar spray to manage thrips is between formation of the first and second true leaf stages, he said.

“In 2011, due to the uncommon appearance of western flower thrips, the new insecticide Radiant was the best-performing product we had,” Leonard said, adding that the chemical is expensive.

On soybeans, the use of insecticide seed treatments has been a valuable tool to manage the three-cornered alfalfa hopper and prevent stem girdling on seedlings. Leonard also said girdling of stems is not significant unless the plants lodge, or fall over, during the late season.

Jeff Davis, LSU AgCenter entomologist, said velvetbean caterpillars and soybean loopers will be showing up in soybeans this time of year. Davis said loopers have been found that are resistant to the insecticide Intrepid, and he said the higher rates of 6 ounces, or even 8 ounces, per acre is advised.

He advised scouting not only for insects, but also for canopy defoliation. He said a 20 percent canopy loss can reduce yields by four bushels per acre, which could amount to $52.

Boyd Padgett, LSU AgCenter plant pathologist, said he’s not seeing a lot of disease this year, mainly because of the drought. However, aerial blight has started showing up in soybeans in the coastal parishes.

Brooks Blanche, LSU AgCenter agronomist, is conducting research on cotton varieties and looking for consistency across planting dates.

“We’re looking for the varieties that are resilient across planting dates,” he said.

Dennis Burns, LSU AgCenter extension specialist, helps farmers learn the benefits of precision agriculture, which is the use of computers and digital media to learn more about land and crops. For example, a yield monitor in the tractor gathers precise data about the crop as it’s being harvested. This information is then analyzed and used the next year to determine exactly where fertilizer should be applied.

“To get the most use out of the system, the equipment needs to be calibrated,” Burns said. “That’s not something you do once. You have to do it again and again.”

Burns does not recommend one brand of computer equipment over another, but he does recommend sticking with the same brand for the various components.

“All of the equipment out there is good, but sometimes one system doesn’t communicate well with another system,” he said.

Ron Levy, LSU AgCenter soybean specialist and director of the Dean Lee station, said the United Soybean Board is funding a trial at the station to study what agricultural practices might be used to optimize yields.

Much of the other research at the station would not be possible without funding from Cotton Incorporated and the Louisiana Soybean and Grain Board, Levy said.