(09/06/16) CHASE, La. – A newer sweet potato variety has finally overtaken a tried-and-true industry standard in terms of acreage grown in Louisiana, producers heard at the LSU AgCenter Sweet Potato Research Station field day on Aug. 31.

Louisiana sweet potato farmers now grow more acres of the Orleans variety than the Beauregard, which the AgCenter developed in the 1980s. Orleans is similar to the popular Beauregard but has a more uniform shape that offers a 10 to 15 percent gain in premium grade quality, said AgCenter sweet potato breeder Don LaBonte.

It is easy for producers to transition from Beauregard to Orleans, he said, because there is virtually no difference in production practices.

Another recently released variety, the copper-skinner Bellevue, is a “breakthrough variety,” LaBonte said. It has high yields, great shape and good late-storing qualities. Bellevue potatoes stay solid and keep their weight in the May-to-July season that is important for the fresh market, LaBonte said.

Others topics at the field day included pest management and updates on the industry and AgCenter research and outreach efforts. About 135 people attended the event, including several from out of state and foreign countries.

Wet weather in the spring meant some acres of sweet potatoes never got planted, said AgCenter extension associate Myrl Sistrunk. While acreage in Mississippi in North Carolina grew this year, Louisiana acreage remained about the same as last year at 9,300 acres. Now rain is delaying harvest, especially in south Louisiana.

“If you could describe this year in a word, it would be ‘wet,’” Sistrunk said.

Some damage to sweet potatoes as result of the August flooding in south Louisiana is anticipated, he said, although the extent will vary from field to field and won’t be clear until harvest. Recent rains have kept farmers from making timely pesticide applications to control late-season insects and weeds, including loopers and sedges, but Sistrunk said he doesn’t expect they will cause yield-reducing problems.

AgCenter agronomist Arthur Villordon said new data suggest that phosphorus applications not only provide nutrients for sweet potato growth but also may improve the length and shape of the root. But too much phosphorus can reduce a plant’s ability to take up iron and zinc, he warned, adding that applications should be adjusted according to the variety and soil phosphorous content.

“We shouldn’t be applying more than 120 pounds per acre of phosphorus in addition to what’s in the soil because it tends to reduce the yield of the crop,” Villordon said.

Two new weed control technologies expected to become commercially available next year present new concerns about herbicide drift and damage to sweet potatoes, said AgCenter weed scientist Donnie Miller. Growers who plan to use the new Enlist and Xtend cropping systems, which allow 2,4-D and dicamba, respectively, to be sprayed on emerged row crops, must carefully follow application regulations to avoid herbicide drift and make sure they clean out spray tanks, he said.

Miller showed field day attendees test plots of sweet potatoes that were sprayed with one tenth of the rate of either 2,4-D or dicamba 30 days after planting and had severe damage that prevented plants from developing any potatoes. As little as a hundredth of the rate of either herbicide can affect plants, he said.

Bruce Garner, AgCenter agent in West Carroll Parish, said computerized hole-selection software, surge valves and soil moisture sensors are all options growers should consider to irrigate more efficiently.

AgCenter irrigation engineer Stacia Davis said the software and surge valves control how much and where water is used, while sensors help determine when to irrigate.

“We’re trying to use technologies so irrigation can be the most conservative and cost you the least amount of money while still being effective and having good quality and good yields,” she said.

AgCenter research associate Theresa Arnold explained the lengthy process of sweet potato variety development, which requires trials in Louisiana and several other states — including Alabama, Mississippi, Arkansas and California — before a variety is identified that can be introduced commercially. Newer varieties such as Bellevue and Orleans were evaluated for seven to nine years before they were officially released, Arnold said.

Funding from the National Clean Plant Network has benefitted virus testing work in the sweet potato foundation seed program, said AgCenter plant pathologist Chris Clark. He is studying how viruses spread and finding ways to produce cleaner seed, to test seed to improve quality and to screen seeds for resistance to diseases.

AgCenter entomologist Jeff Davis said the AgCenter recently began collaborating with AgBiome, a North Carolina biotechnology company, to identify biological controls for the sweetpotato weevil.

AgCenter entomologist Julien Beuzelin said the sugarcane beetle has been a major concern for sweet potato growers in the past decade, although populations have been low in the past two years. Treatment with Belay, a neonicotinoid insecticide, prior to planting or at lay-by helps control sugarcane beetles as well as banded cucumber beetles, he said.

Tara Smith, director of the Sweet Potato Research Station, said cucumber beetles have been challenging to control in sweet potato fields this year, and some producers have struggled to maintain populations below threshold levels. Spring rains also prevented timely applications of Telone, one of the many products the AgCenter is evaluating for nematode control, she said.

AgCenter pesticide safety coordinator Kim Pope Brown reviewed recently updated worker protection standards, which now include more record keeping, changes to minimum age requirements, annual retraining of workers, and oral and posted notification of restricted entry intervals for pesticide applications. Full compliance will be required by January 2018.

Glen Gentry, an animal scientist at the AgCenter Bob R. Jones-Idlewild Research Station, told about his research looking for effective controls for feral hogs, including sodium nitrite and traps. The hogs, which reproduce quickly and can adapt to many environments, root up crops and cause other problems for farmers in Louisiana.

U.S. Sweet Potato Council director Kay Rentzel told attendees the Food and Drug Administration has extended the compliance period for the Food Safety and Modernization Act. She said U.S. Rep. Ralph Abraham, of Mangham, plans to hold a briefing for members of the House Agricultural Committee in late September to address labor and water issues facing the sweet potato industry.

Rogers Leonard, AgCenter associate vice president, said recent flooding, along with reduced funding for the TOPS scholarship program, could worsen LSU’s already less-than-ideal budget outlook. The College of Agriculture will be affected because of the potential for a decline in student enrollment, and the AgCenter is continuing to look for ways to make more efficient use of its employees and facilities, he said.

LSU AgCenter sweet potato breeder Don LaBonte, left, talks about traits of different sweet potato varieties on display during a field day at the Sweet Potato Research Station in Chase, Louisiana, on Aug. 31. Photo by Olivia McClure/LSU AgCenter

LSU AgCenter agronomist Arthur Villordon discusses how nutrients such as phosphorous affect sweet potato development during a field day at the Sweet Potato Research Station in Chase, Louisiana, on Aug. 31. Photo by Olivia McClure/LSU AgCenter

LSU AgCenter animal scientist Glen Gentry, left, tells attendees of an Aug. 31 field day at the Sweet Potato Research Station about feral hogs and possible control methods that he is studying. Photo by Craig Gautreaux/LSU AgCenter

Attendees of an Aug. 31 field day at the Sweet Potato Research Station listen as LSU AgCenter entomologists Julien Beuzelin, far right in yellow shirt, and Jeff Davis, right in purple shirt, give a presentation on their research. Photo by Karol Osborne/LSU AgCenter