Farm Progress

Sweet potato grower adapts with information, innovationSweet potato grower adapts with information, innovation

Roy Roberson 2

December 6, 2006

8 Min Read

Bailey, N.C., sweet potato grower Jim Jones doesn't consider himself to be a pioneer in the industry, but his innovations with equipment, seed technology and pest management have put him near the head of the pack among upper Southeast growers.

He cut his teeth growing yams in the truck middles of his grandfather's tobacco crop.

When he was 14 years old, Jones grew his first sweet potato crop. Today his micro-propagation cuttings are grown across the Southeast, his sweetpotatoes sold up and down the east coast, and his name has become synonymous with sweet potatoes in North Carolina.

“Micropropagation is the name of the game in sweetpotatoes,” Jones says. The propagation lab at North Carolina State University takes cuttings off the mother stock plants that are known to be free of insects and diseases. Jones buys cuttings, also called mother plants, in clay pots the last week of January to the first week of February.

He has a separate greenhouse for each variety he gets from the North Carolina State University Micropropagation Unit. A wood-frame greenhouse — 20'X80' — one-third center area is screened in for mother plants. Each greenhouse features electricity on thermostats and automatic timers for water and fertilizing.

Before entering each greenhouse, everyone goes though a double entry area for sterilization with a fogging system that completely covers the body to eliminate insects and diseases getting into the greenhouse. “We don't feel it's enough to just step in a clorox-filled tub,” he says

“At the start of each growing season, we sterilize everything with a Clorox/Oxidate/fungicide/spore killer mixture to make sure everything is spic ‘n’ span and ready for new mother plants to be micropropagated.”

He transplants the mother plants in hanging baskets inside a screened cage in one of his greenhouses. As the plants grow vines, he cuts the 12-14-inch long vines into two-node cuttings, continuing until he fills each greenhouse with a specific variety. He currently grows five varieties of sweet potatoes, with one greenhouse generally designated for a specific variety.

By the time he gets his five greenhouses filled with cuttings, he begins planting in the field. Each house will generate a new crop of cuttings six or seven times a year, up until the third week of July.

“We take 100 daughter plants that all came from one mother plant, and by doing so you have the same plant with the same momma and daddy. The heredity should all be the same. The bottom line is a very uniform crop. It doesn't always work out as the ideal because of weather and other conditions, but in general we get a very uniform crop,” Jones says.

Since he started in the mid 1990s with micropropagation, Jones has become one of the largest suppliers of sweet potato cuttings in the Southeast.

“It all started when a scientist from North Carolina State brought me a grocery bag of micropropagated sweet potatoes. They did so much better than the plants that came from our traditional certified seed,” he says.

Jones was one of the first growers to use micropropagated sweet potatoes. From the farmer's perspective, he took the first chance with the grocery bag full of sweet potatoes. Now, virtually 100 percent of North Carolina growers raise micropropagated sweet potatoes.

Jones also helped design an innovative planter/sprayer that is now being copied by growers across the state. Built by Strickland Brothers Equipment in Spring Hope, N.C., the big rig allows him to go into land that is bedded up, with a knockoff bar that takes the row down to planting depths. A middle buster opens the row back up to the root zone.

Capture is applied by two fan-tip nozzles that spray the open row, plus the dirt thrown out of the row. Capture insecticide is primarily to control wireworms, which is the leading pest for Southeastern sweet potato growers. Capture is a product that has replaced a number of foliar applications.

“In working with North Carolina State in the Sweet potato IPM Project, we discovered our foliar sprays weren't working, so we switched to Capture, which is a pyrethroid insecticide widely used on corn and other small grain crops. “Based on results so far this year, I would say we are getting much better insect control and much less damage to our sweet potatoes,” Jones says.

For the past three years, Jones has participated in a regional sweet potato IPM project that has made his operation more efficient and economical. The project is part of a cooperative IPM program with sweet potato growers in Louisiana, Mississippi and Alabama.

Mark Abney became project leader of the multi-disciplinary program in 2005. From the entomology side of the program, in 2006, 16 North Carolina sweet potato growers participated in the field research component of the program.

Growers participating in the project agree to leave 16 rows of sweet potatoes that are not treated with any insecticide or nematicide. The IPM Team put in tests in 35 grower fields in the four cooperating states to compare treated and untreated sweet potatoes.

“What it allows us to do is compare treated and untreated strips. When we harvest the sweet potatoes, we get a good range of insecticide use and amounts. By comparing different treatments, different rates and different application methods, we can tell what is and what isn't working,” Abney says.

“Some guys are putting on bare minimum insecticides, while others are using a number of different sprays. Looking at it across the whole spectrum, you can see treated versus untreated and the different chemicals and determine the level of insect damage based on the management practices used,” Abney explains.

The program worked well for Jones, who was quick to adapt the IPM practices to his 560 acres of sweet potatoes. In the past we sprayed every 7-10 days with different foliar insecticides. Now, we put on Capture with the big cultivator and at lay-by we will come back apply the second half of our Capture.

“This year, we have seen less than five percent damage, and in some cases zero damage from wireworms. On a bad year, we have seen 50 percent or more damage. So, if Capture continues to work as well as it has this year, it will be a big economic saving both in terms of cost of insecticides and application, plus the better quality of our sweet potatoes,” Jones explains.

Information from the IPM program is closely tied to the use of his new cultivator/planter. Behind the fan-tip nozzles are rolling spiders that are set at angles and throw treated soil back into the row. This helps blend the mixture in the soil. The spider tips are followed by a cultipacker that knocks the row back flat for planting.

He comes back with Valor herbicide, banded across the top of the row and over-the-top of that with the transplanter. The idea is to disturb the bedded plant as little as possible, Jones explains.

“We can run this rig about four miles per hour and prepare and plant four rows at a time. We try to stay about an acre ahead of the transplanter. We can plant nine acres a day with a four-row transplanter, but we sometimes run two or three transplanters. We stay as close behind the cultivator as possible with the transplanter to avoid losing moisture in the plant beds,” Jones explains.

His big problem with weeds comes from pigweed. “All the other weeds combined don't worry me as much as pigweed,” he says. After trying a number of herbicides, he contends his best control for pigweed comes from waiting till they get above the sweet potatoes and using a wick bar coated with glyphosate.

Though more attention has been given to pigweed resistance in the major row crops planted to Roundup Ready seeds, Jones says he has seen indications of glyphosate resistance in lambsquarters. It's not just the cotton and soybean growers that will be affected by resistance problems, he says. In one field he sprayed lambquarters with glyphosate pre-planting and came back and wicked it with glyphosate and still didn't kill the weeds, he laments.

Jones only grows sweet potatoes, but rotates his crop with neighboring farmers who grow cotton, soybeans, corn, tobacco and other traditional row crops. If farmers growing Roundup Ready cotton and soybeans get glyphosate resistance in the fields he will later plant to sweet potatoes, Jones says he will have an even bigger pigweed problem.

His innovative growing techniques in sweet potatoes got Jones and his wife Barbara interested in micro-propagated blackberries. “Blackberries happened really by chance. A man in Charlotte, N.C., who operates a market and grows some of his own produce, called me to inquire about buying sweet potatoes. Subsequently, we became friends. He had seen our greenhouse operation for sweet potatoes, and suggested we could grow blackberry plants the same way,” Jones recalls.

At the time there was no source of blackberry plants and there was no protocol for certified blackberries in the Southeast. “We ended up working with a blackberry breeder in Arkansas and the bramble and sweet potato specialists at North Carolina State,” he says. We have had no problem selling all our blackberry plants and the four acres of blackberries that we grow here,” Jones concludes.

Micropropagation, IPM programs and innovative new equipment have helped place Jim Jones among the country's most elite sweet potato growers. The real secret though may be his devotion to a single crop and his ability to adapt new things to the art and science of growing sweet potatoes.

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