News Release Distributed 08/08/14CHASE, La. – Sweet potato farmers got updates on varieties, diseases, weeds and other topics at a field day on Aug. 7 at the LSU AgCenter Sweet Potato Research Station. The event attracted about 140 participants from Louisiana and seven other states.
AgCenter sweet potato breeder Don LaBonte said Orleans, a newer variety whose taste, look and yield are similar to the popular Beauregard, has been gaining traction because of its better shape.
While Beauregard is “a great standby” and Orleans holds promise, LaBonte is also evaluating specialty varieties, which are in increasing demand. Varieties being tested at the station include LA 07-146, which was recently named Bayou Belle and is licensed to ConAgra Lamb Weston; flavorful Evangeline; white-fleshed Bonita; copper-skinned 06-52, which is also high-yielding in sand; and Burgundy, which has deep red skin and exceptional flavor but only decent yields.
Beauregard remains the dominant variety in Louisiana, according to AgCenter sweet potato extension associate Myrl Sistrunk. He said more than 9,000 acres of sweet potatoes have been planted in Louisiana this year, which is up compared to last year’s 7,300 acres.
While planting was delayed because of cold, wet weather, conditions have been mostly favorable throughout the growing season. The crop is slightly ahead of schedule, and Sistrunk predicts harvest will be in full swing in mid-September.
LaBonte said the AgCenter’s sweet potato breeding program is trying to develop varieties that can be planted and harvested earlier.
“They tend not to store as well, but developing earlier varieties still matters because an earlier crop means growers can make money sooner,” he said.
When growing multiple varieties, farmers need to pay attention to the unique needs of each variety, said AgCenter horticulturist Arthur Villordon. He told attendees how nutrients, planting date, planting density and other decisions affect growth and quality of sweet potato roots.
“Evangeline is sensitive to ammonium in pre-plant fertilizers like urea,” he said. “It must be managed differently. Orleans and other varieties are much more versatile in nutrient programs.”
No matter the variety, it is crucial to distribute the appropriate nutrients evenly, Villordon said. Growers should check plants 30 and 60 days after planting to determine the correct inputs – nitrogen helps with size, for example – if any are even needed.
Theresa Arnold, AgCenter research associate, talked about how spacing, planting date and harvest date affect quality of sweet potatoes. Many people are not just selling for the fresh market now, she said, so it is important to identify which combinations of conditions produce potatoes that suit different marketing needs.
AgCenter entomologist Julien Beuzelin said soil insects are a problem for sweet potatoes, so choice of variety and resistance development are important.
In tests last year, the Murasaki variety, which is not widely grown in Louisiana, had only 18 percent injury while more common varieties saw up to 40 percent damage, he said. Newer specialty varieties like Burgundy and Bayou Belle fared better, however.
Beuzelin is also evaluating insecticides. He told growers that if they have been relying on bifenthrin, they should consider other options because lately it has not provided good control of some soil insects, namely the sugarcane beetle.
Tara Smith, resident coordinator at the Sweet Potato Research Station, encouraged farmers to start thinking about nematode management now. Treatments can be expensive, she said, but will pay for themselves in cases of significant nematode pressure.
More sweet potato growers are dealing with nutsedge, a perennial weed that is similar to pigweed, according to AgCenter weed scientist Donnie Miller. There is not much available right now to control it because Sandea is no longer labeled for use on sweet potatoes, but Miller is working to identify options. Dual Magnum has been working, he said, but depending on one herbicide creates potential for resistance.
Miller’s graduate assistant Tommy Batts told attendees about his project on how herbicide drift affects sweet potatoes. Monsanto and Dow are planning to release new technologies that, if used on soybeans and cotton planted near sweet potato fields, could drift and cause damage such as swollen roots.
Miller said it is important to study the effects of the new products’ active ingredients – 2,4-D and dicamba.
AgCenter engineer Randy Price demonstrated and discussed unmanned aerial vehicles, or drones, which can be used to scout fields and monitor irrigation.
Chris Clark, AgCenter plant pathologist, said white rust disease has been showing up on morningglories, and it can spread to sweet potatoes. While the rust doesn’t negatively affect sweet potato yields, he said, the ease with which it spreads highlights the importance of preventing viruses through the AgCenter’s foundation seed program.
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