Stevia is so new to North Carolina that researchers and farmers say there are far more questions than answers on producing the crop, but because of an established market and growing demand, they are committed to expanding acreage in the Tar Heel State.
Stevia uses similar production practices as tobacco, which makes it a good joint crop with tobacco in North Carolina. However, David Shew, professor of plant pathology at North Carolina State University, said farmers must do their homework before deciding to grow stevia. It’s not for everybody.
“You need to start with the idea that you are willing to accept a challenge because there are unknowns at this point, but stevia does have a lot of potential in our climate,” Shew explained at a stevia field day held at Carter Farms in Eagle Springs, N.C., on June 24.
“Our goal when we started this program two years ago was to branch out throughout the Coastal Plains to get it exposed to growers in the state so people can make up their own minds,” Shew said. "They can see the crop, they can see what it takes to grow it, and they can get an idea of what their returns may be. They need to find out is this for them.”
Stevia (Stevia rebaundia) is an herbaceous perennial native to Paraguay. It is a rapidly emerging specialty crop in the United States as more companies seek improved sugar substitutes. Stevia leaves contain glycosides up to 300 times sweeter than sugar that can be extracted for use as a nonnutritive sweetener. The plant has been used in other countries for many years as an all-natural, no-calories sweetener.
The United States banned stevia usage in the early 1990s, unless labeled as a dietary supplement. But in 2008 USDA approved stevia for use as a food additive. Since then, stevia products have mushroomed at retail outlets across the United States with such brands as Truvia, Zevia, Sweet Leaf and Stevia in the Raw.
Hal Teegarden, vice president of agricultural operations of Sweet Green Fields, which is currently the only source of stevia seed and transplants in North Carolina, noted that demand for stevia is strong and growing. The United States is the largest single market for high purity stevia extracts at approximately 300 metric tons of finished products annually. This represents roughly 65 percent of the global market for high purity stevia extracts in 2011.
“Yes there are challenges to growing stevia, but we are really excited about where we find ourselves today,” Teegarden said. “It’s a growing crop, it’s a growing industry, and it’s a growing market. It certainly represents an opportunity for U.S. growers as the industry grows and demand grows.”
Acreage expanding each year
Stevia production began in North Carolina in 2011 with a few test acres in Bertie County. Acreage has increased each year since then and stevia is now grown on nearly 400 acres in 10 counties in eastern North Carolina. Production can now be found in Bertie, Halifax, Nash, Johnston, Chatham, Hartnett, Hoke, Roberson, Moore and Randolph counties. Shew said most of the fields are in sandy soils, but there is potential for stevia in clay soils as well.
Stevia begins as a seed, is seeded into float trays, and is then grown in float bays that are used for production of tobacco transplants. Cuttings can also be used to start plants. Plants are grown for 10 to 12 weeks before transplanting to the field, similar to transplanting tobacco seedlings.
There are currently no herbicides labeled for use on stevia, except Roundup prior to emergence of established crops. “We are pursuing labels for use in North Carolina,” Shew said.
To date, two stem rot diseases have been identified as potential limiting factors in production. “These pathogens are well known to growers in the state as they also cause diseases of many row and vegetable crops,” Shew said. “Germplasm of stevia is being screened for resistance to these diseases as well as other known pathogens of field crops in North Carolina.”
A big plus for stevia is that insects have yet to be a problem for the crop in North Carolina. Additionally, none of the major tobacco diseases attack stevia. And, deer don’t like the crop. In fact, Billy Carter, who produces stevia in Moore County, where the field day was held, said deer wouldn’t touch his stevia plants last year.
“We have a lot of deer pressure on this farm, but we didn’t have any deer pressure on our stevia field,” Carter said.